by John W. Lydon

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Seven mineral deposit types have contributed over 90% of the value of non-ferrous metalliferous mineral production in Canada. Based on average 1996 to 2005 inflation-adjusted metal prices, to the end of 2005 the most productive mineral deposit types have been

1. magmatic Ni-Cu deposits (>$372 billion), mainly from Proterozoic rocks in the Sudbury and Thompson areas;
2. volcanogenic massive sulphide (VMS) deposits ($192 billion), mainly from Archean greenstone belts of Quebec and Ontario, the Proterozoic volcanic belts of Manitoba, and Paleozoic volcanic rocks of New Brunswick; and
3. lode gold deposits ($132 billion), mainly from quartz-carbonate veins of Archean greenstone belts of Quebec and Ontario. Collectively, porphyry, sedimentary exhalative (SEDEX), Mississippi Valley, and uranium deposit types have contributed about $140 billion, and diamonds, a relatively new but growing mineral commodity for Canada, has contributed $8 billion.

The dollar equivalent of metal contents per tonne of ore mined over the past five years range from about $130/t to about $350/t for most underground base metal and diamond mines, and $90/t to $300/t for most underground Au mines. Dollar equivalent of metal contents exceed $450/t only in a few metal mines. The average ore dollar equivalent of metal contents range from $10/t to $45/t for open pit metal mines. The most valuable ores are those of U deposits of the Athabasca Basin, where past production has averaged dollar equivalent of metal contents of $540/t, and current reserves are worth $1,000/t to $11,000/t, based on the ten year average value for U, or over three times these values based on the average 2006 uranium price.

About 50% of production and 57% of the $1.57 trillion of the non-ferrous metal and diamond content of total mineral resources are associated with volcanic arcs and back-arcs that were accreted to, or built upon, continental margins during the assembly of supercontinents. Deposit types include VMS, porphyry, komatiitic Ni-Cu deposits, and intrusion-associated Au, as well as orogenic lode gold deposits associated with collisional tectonism. Mineral deposits of mafic-ultramafic magmas, whose emplacement is associated with structures that dislocate or perforate continental crust and penetrate the mantle, and include magmatic Ni-Cu and kimberlite diamond deposits, account for 40% of production and 33% of total mineral resources. Mineral deposits associated with intracontinental or epicontinental sedimentary basins account for the remaining 10% of both production and total mineral resources.

One of the objectives of the Geological Survey of Canada's (GSC)Consolidation of Canada's Geoscience Knowledge (CCGK) program was to establish a national Cooperative Geological Mapping Strategy (CGMS) agreed to by the federal and provincial governments. In order to facilitate discussions among non-technical decision-makers in governments to achieve the program's objective, a resource required in the early stages in its mandate was an overview of Canada's mineral resources that emphasized their socio-economic contexts. This overview was delivered to the program in October 2003 and subsequently released to the public as GSC Open File 4668 (Lydon et al., 2004).

The interest shown by the geoscience community in this overview of Canada's mineral resources, especially by those geoscientists whose expertise is other than in mineral deposits, has prompted the update and expansion of the information contained in GSC Open File 4668 presented here. The main revisions include

1. An update of production and reserve statistics to December 2005.
2. Realignment of categories of mineral resources to more closely conform to CIM standards established by the Canadian Institute of Mining (CIM) Standing Committee on Reserve Definitions and published in the CIM Bulletin, October, 2000. The major impact of this was to reduce the amount of metal contained in the “resources not being mined” category of GSC Open File 4668, especially for those deposits whose resources have been re-estimated since the introduction of National Instrument 43-101 by the Canadian Securities administrators in 2001.
3. Reconciliation of the databases used for GSC Open File 4668 with those expert databases of Appendix 1, which resulted in the addition of deposits, mainly of the lode gold deposit type, to the database.
4. The addition of some other deposit types to the database, namely Ag-rich veins, W skarns, and diagenetic Cu.

Objectives

Non-technical decision-makers in government need to know the socio-economic impacts of mining and in particular their geographical distribution, the contribution of mining to the economy, where new development could take place, and how governments can influence the discovery and development of new mineral deposits. Geoscientists who are not expert in mineral deposits need sufficient understanding of the geological attributes and settings of mineral deposits in order to place them in the context of their own fields of expertise, so that their knowledge can be applied to problems of mineral resources. These two sets of information are the essence of economic geology. The one emphasizes that the right economic conditions must be in place before a mineral deposit becomes an economic resource, and the second emphasizes that mineral deposits only occur where the right geological conditions exist, and not where economic or political priorities would like them to be. In attempting to combine both the economic and geological aspects of mineral resources, this article is divided into three parts:

1. An outline of the range of factors that influence mineral resources statistics.
2. A summary of current and historical contributions by mineral resources to Canada's economy, and a brief description of the relationship between the geographical distribution of mineral resources and the geological architecture of Canada.
3. A brief description of each mineral deposit type of economic importance to Canada, concentrating on its most significant economic and geological characteristics.

Dollar Equivalent of Metal Contents

It is difficult to directly compare the economic value of different resource categories of different mineral deposits using conventionally reported statistics because different mineral deposit types are mined for different commodities and different units of measurement are employed for different commodities and resource categories. Production from metalliferous mineral deposits is usually reported as the quantities of metal produced and/or the values of metal recovered (e.g. Fig. 1). In contrast, mineral reserves and mineral resources are usually reported as tonnages of ores, and the grades of the economic components that those ores contain. Comparisons are further complicated by the use of different weight units: metric tonnes (t), short tons, or pounds for base metals; troy ounces, grams, or kilograms for precious metals; and specialized units such as short ton units or metric tonne units of WO3 for tungsten (containing 15.86 lbs and 7.93 kg of tungsten, respectively). In order to allow a more direct comparison between different deposits, the unit of measurement of mineral resources used here is the dollar equivalent ($Eq) of the metals contained in the ores. This number is obtained by multiplying the amount of metal contained in a metric tonne of ore by the average inflationadjusted ten year price of the metal (Table 1). Thus production from, or mineral resources in, a deposit is expressed as a single dollar equivalent number for each resource category, and represents the sum of the dollar equivalents of all economic commodities contained in the category. Grades are expressed as $Eq/t, which again is a sum of the dollar equivalents of all economic commodities contained in a tonne of ore.

Although a ‘dollar equivalent value' has the advantage of giving a direct indication of the magnitude of the economic worth of a mineral deposit, it is not a measure of the actual and current economic value of a mineral resource. It does not take into account that only a certain proportion of a mineral deposit can be mined (because of engineering and other factors), and that only a proportion of the metals contained in the ores can be recovered by the mineral beneficiation process. Furthermore, the dollar equivalent value of a deposit or its ores does not provide an indication of the profitability of the mining ventures, because costs of mining, beneficiation, transport, smelting, etc. vary widely depending on the mining methods and the metallurgical properties of the ores. Finally, because the prices of metals vary over time, the dollar equivalent value of resources reported here can be taken only as the maximum value that could have been derived from the deposit if it were completely mined out over the period 1995 to 2005.

Definitions

The amount of the valuable commodity(ies) that may be potentially mined at a profit are calculated using a mathematical model of the mineral deposit based on a systematic sampling by drill cores. The model contains assumptions on a range of factors that include

1. the validity of the geological model used to interpolate between sampling points;
2. the choice of cut-off grades that define the boundaries of the mineral resource;
3. the mining method, which determines what parts of the deposit are feasible to mine and the amount of ore dilution by unmineralized host rocks that will take place;
4. the mineral beneficiation methods, which determine the proportion of the ore minerals that can be recovered from the ores;
5. various other economic, marketing, legal, environmental, social, and governmental factors that affect a potential mining operation.

The grade and amount of the valuable commodities estimated for a mineral deposit are classified as ‘mineral reserves' only if technical studies and tests have shown that it would be feasible and economically viable to mine the mineral deposit and deliver the products to a treatment plant. Otherwise, the estimated grades and tonnage of a mineral deposit are classified as ‘mineral resources'. In most cases, mineral resources are considered to be mineral reserves only if they are part of a mineral deposit that is being actively mined, or the mineral deposit is under active development in preparation for mining. Even so, part of the mineral inventory of a mineral deposit that is being actively mined may be classified as mineral resources if, at the time of reporting, that part of the deposit in which they occur has not been included in the current mining plan.

In Canada, the criteria for reporting and classifying mineral resources are stipulated by National Instrument 43-101 (NI 43-101), which was introduced by the Canadian Securities Administrators in 2001. National Instrument 43- 101 uses the definitions of different categories of mineral reserves and resources formulated by the Canadian Institute of Mining Standing Committee on Reserve Definitions (CIM Standards, CIM Bulletin, October 2000). The CIM Standard subdivides mineral reserves into “proven” and “probable” according to the degree of certainty of whether they will be mined, and mineral resources into “measured”, “indicated”, and “inferred” according to the degree of certainty of their existence. The criteria for establishing the degree of certainty of existence of mineral resources are not specifically defined by the CIM Standards and it is left to the professional judgment of the “qualified person” calculating the quantities and grades of a mineral resource to decide whether they are classified as measured, indicated, or inferred. Hence, the statistics for mineral resources contain an element of subjectivity. The grades and tonnages for mineral reserves and mineral resources are very changeable, especially for active mines. As mining progresses, reserves are diminished but these may be replaced as continued mine development allows mineral resources to be reclassified as mineral reserves and, in turn, continued exploration discovers new mineral resources. Similarly, changing economic, social, or political conditions, or improvements in geological knowledge of the mineral deposit, may change the parameters of the mathematical mine model referred to above. Modifications to the mine model may cause an upward or downward revision to the grades and tonnages of all mineral resource categories. Thus, there is not a single objective set of tonnage and grade statistics for a single mineral deposit because the statistics are specific for a particular time and a specific qualified person.

Production usually refers to the amount of metal in the product that is delivered by a mine to a smelter or refinery. In order to fully reconcile production statistics with statistics for reserves and resources, it is necessary to know the amount and grades of the ore that is mined, that is in stockpiles, and that is milled, and also the recovery rates for each commodity by the beneficiation process. Although a most corporations now report the amount and grade of ore milled and recovery rates, and some also report the amount of ore mined in a reconciliation of reserve data, the lack of ready public availability of all the information that is needed to calculate the amount of metal contained in ores mined has necessitated author's estimates in the compilation of statistics presented here.

Compilation of Statistics

Geoscientists and mineral explorationists are primarily interested in tonnages and grades of mineral resources, whereas economists and financial specialists are more interested in the amounts and values of metals produced. The two sets of statistics are related by the amounts and grades of mill feed, the recovery efficiency of the concentrating process, and metal prices. Both sets of statistics are given in Appendix 1 (see accompanying DVD), which attempts to list all non-ferrous metal and diamond deposits in Canada for which a resource has been measured (Fig. 2). A summary of these statistics, in terms of quantities of contained metals for each deposit-type is given in Table 2, and a summary of the dollar equivalent metal content is given in Table 3.

Statistics for production were compiled by a variety of methods. For deposits mined since 1970, production statistics were obtained by adding annual production statistics compiled in digital format by provincial and the federal governments and, particularly for deposits mined since 2000, from corporate annual reports or annual information forms filed with the Canadian Securities Commission (www.SEDAR.com). The data used as production are, in most cases, for “ore milled”, which is more consistently reported than “ore mined”. Where mill head grades were not reported, they were estimated using average recovery rates for the deposit type (Fig. 3). If only the amount of metal recovered is reported, the tonnage and grade of the mill feed is estimated based on average recovery rates and the grade of the previous year-end reserves. Large corporations in particular tend to report production as rounded amounts of major commodities, and include all minor or by-product commodities in an umbrella “other revenues” category. Where there is sufficient reason to suppose recovery of these minor components (e.g. platinum group elements in Sudbury ores), estimates are made based on the ratios of minor components to major components in the previous year-end reserves, or in other cases (e.g. Eskay Creek) on metal ratios of the pre-production estimates of the total mineral resource.

For deposits mined prior to 1970, data were obtained from compilations by provincial governments, the World Minerals Geoscience Database of the Geological Survey of Canada, the compilations of the various deposit types in appendices to this volume, the Canada Minerals Yearbook for the years 1955 to 1970, Cranstone (2002), and Gosselin and Dubé (2005). For these deposits, it has been assumed, unless there is information to the contrary, that the resource reported for the deposit in the general literature was the amount that was mined. For deposits or districts that were mined prior to 1951 and whose cumulative production records are not in provincial databases (such as the Ni-Cu mining of the Sudbury district), estimates of pre-1951 production were based on the annual graphs of Cranstone (2002). Data for reserves are from corporate annual information forms filed with the Canadian Securities Commission (www.SEDAR.com) and corporate annual reports. Data for measured, indicated, and inferred resources for deposits mined since 2002 are from corporate annual information forms.

For deposits not mined since 2002 or that have never been mined, most of the data are historical estimates of resources that do not conform to CIM Standards as required by NI 43- 101. These historical estimates of ‘reserves' are all included in the measured and indicated resources category used here. Data for these historical estimates of resources were obtained from the compilations mentioned above and Natural Resources Canada (1990). An attempt was made to update estimates for mineral deposits not being mined, but re-assessed since the introduction of NI 43-101. Most of these deposits, reflecting mineral exploration priorities of the time, are of the lode gold type. However, the attempt was not systematic or complete.

For purposes of this article, measured resources and indicated resources are combined into a single ‘measured and indicated resources' category, and like the ‘production', ‘reserves', and ‘inferred resources' categories, are used here in the sense that the data incorporates estimates by the author or refers to dollar equivalent values, unless otherwise stated.

IMPORTANT NOTICE: As noted above, the data reported in Appendix 1 (DVD) contain estimates made by the author, and so should be treated only as approximations of the production and mineral resources of the deposits listed. Typographic errors may have occurred in transcription and mistakes made in calculations, and so caution should be exercised in using the data for purposes other than the one here, which is to obtain an overall approximation of the quantity and distribution of Canada's non-ferrous metal and diamond resources.

Metal Prices

Most of the metal prices used here are the 10 year (1996- 2005) averages of the average annual prices reported by the United States Geological Survey Annual Commodity Reviews. These reviews compile data from a variety of sources including Metal Week, Platt's Metals Week, Metal Bulletin, and Engineering and Mining Journal, which collectively report data from a variety of metal exchanges. For base metals, the United States Geological Survey Annual Commodity Reviews uses United States domestic producer prices, which tend to be 5 to 10% higher than prices averaged from the London Metal Exchange (for Pb, the prices are up to 40% higher, and so the London Metal Exchange price for Pb is used in Table 1). These prices have been converted into metric units, inflation-adjusted by using the inflation indices reported by the U.S. Department of Labor, and converted into 2005 Canadian dollars by using the historical annual average exchange rates between the United States' dollar and Canadian dollar as compiled by Werner Antweiler, University of British Columbia, (http://fx.sauder.ubc.ca, last accessed 2007). Prices of U (since 1988) are those compiled by Cameco Corporation (http://www.cameco.com, last accessed 2007).

Socio-economic Contexts of Metalliferous Mining in Canada

In 2004, Canada's non-fuel mineral production was worth $21.7 billion (Fig. 1; McMullen and Birchfield, 2005). This production consists of 23 mineral categories of which 12 are metals, 1 is diamonds, and the rest consist of a range of industrial and construction commodities and Fe ore (Fig. 1). The commodities dealt with in this article are the non-ferrous metals (i.e. all metal categories exclusive of Fe ore in Fig. 1) and diamonds, which together accounted for $12.9 billion or 59.5% of Canada's non-fuel mineral production in 2004.

In 2005, the value of Canada's non-fuel mineral production rose by 7.7% to $13.3 billion, due mainly to an increase in the price of metals led by a 65.4% increase in the price of U (Birchfield, 2006). In terms of quantities of metals, production of Zn and Ag actually decreased by about 15% and Au by 8%. The value of diamond production fell by 19.7%, due in part to the increase in the value of the Canadian dollar against the United States dollar and in part due to the lower quality of diamonds mined during the year. The mining industry contributed $42 billion, or 3.9% of Canada's gross domestic product, in 2005 of which mining contributed 23.7%, primary metal manufacturing (smelting, refining, etc.) 29.2%, metal fabrication 33.7%, and the remaining 13.4% was contributed by non-metallic mineral fabrication. Crude minerals, smelted and refined outputs, and mineral products contributed $64.2 billion to the value of Canada's exports in 2005. This represented 14.7% of Canada's total domestic exports of $435.8 billion. Metallic mineral and mineral product exports accounted for 75.8% ($48.7 billion) of the total value, non-metal exports accounted for 18.8% ($12.1 billion), and coal and coke accounted for 5.4% ($3.5 billion) (Birchfield, 2006).

Employment in the metal mining industry in 2005 included 21,519 employees in mining, which spawned an additional 84,000 jobs in primary metal manufacturing and 199,000 jobs in metal fabricating. Most of the people employed in mining and primary metal manufacturing live in northern communities of Canada's provinces and territories, particularly those that historically owe their founding to the mining industry, such as Timmins in Ontario, Noranda in Quebec, Flin Flon in Manitoba, and Yellowknife in Northwest Territories, as well as over 100 other communities. The number of people involved in mining in 2005 was 4.8% lower than in 2004, continuing a 10 year trend of declining employment as the number of mines being operated in Canada continues to decline. In 2005, four metal-producing mines closed and only one (Voisey's Bay Ni-Cu mine in Labrador) opened.

On the brighter side, the potential for new mines in Canada was given a strong vote of confidence by the international mineral exploration industry with an investment of $1.3 billion in 2005, doubling the amount that was invested in 2000 (Bouchard, 2006). This makes Canada the preferred destination for exploration dollars for the third consecutive year, ahead of South America and Australia. Of this total, $949 million was spent in searching for new mineral deposits, $225 million on appraising known deposits with a view to a production decision, and $130 million in exploration at existing mines. Of the $949 million spent on looking for new mineral deposits, $381.6 million (40%) was for precious metals, particularly Au, $206.8 million (22%) for diamonds, $196.7 million (21%) for base metals, and $86.5 million (9%) for U. About 80% ($761.8 million) of this exploration expenditure was more or less evenly spread across Ontario, Nunavut, British Columbia, Quebec, and Saskatchewan, with each jurisdiction receiving between $126.5 and $168.3 million in exploration investment. Exploration expenditures make substantial contributions to the economies of northern and remote communities, which are used as logistical support and supply centres, and provide employment opportunities for the local residents.

Junior mining companies were responsible for attracting 58% of the 2005 mineral exploration investment in Canada, for the second year in a row surpassing the investment made by the major mining companies, a situation not encountered since 1987 (Bouchard, 2006). The success in attracting this investment capital has been helped, since October 2000, by the 15% federal investment tax credit tied to the flowthrough- share mechanism, and similar tax credits and other measures in different provinces and territories (Bouchard, 2006).

Canada is the world's leading producer of potash (not dealt with here) and U, and third in the production of Ni, platinum group elements (PGE), and diamonds. Canada is no longer one of the top three producers of Zn, Pb, Cu, or Au, more because Canadian production of these commodities has gradually declined over the past decade rather than increased production by other countries.

Economic Characteristics of Mineral Deposit Types

The total value of non-ferrous metal and diamond ores mined in Canada to date is here estimated to be $Eq845.7 billion, based on the data compilation and processing methodologies described above. This number is a minimum, because it does not include many of the smaller deposits mined in the 19th and the beginning of the 20th centuries, and because the production records for some mines are incomplete. However, insomuch as >95% of the metals produced in Canada has taken place since 1920 (see plots in Cranstone, 2002), this number probably accounts for well over 90% of the metals that have been mined and also captures all diamond production.

Different metals (Fig. 1) tend to occur in different deposit types (Fig. 4). The great majority of non-ferrous metal and diamond production in Canada has been derived from eleven mineral deposit types (Fig. 5), of which only six are currently being mined (Fig. 6). Although most deposit types produce more than one metal, either as co-products or byproducts, some deposit types, such as lode gold and uranium deposits, are essentially monometallic with >95% of the value of the ores being supplied by one commodity (Fig. 5). The geological characteristics of these deposit types are described and discussed in detail elsewhere in this volume (Dubé and Gosselin, 2007; Eckstrand and Hulbert; 2007; Galley et al., 2007a; etc.), but are briefly summarized, together with their economic characteristics, in later sections of this article.

Production

The main changes that have contributed to the differences in the relative importance of metal sources between historical (Fig. 4A) and current (Fig. 4B) mineral production has been the decline in the number of volcanogenic massive sulphide (VMS) deposits being mined, and the cessation of mining from sedimentary exhalative (SEDEX), Mississippi Valley-type (MVT), paleoplacer U, and most vein deposits. These changes have mainly impacted the sources for Zn, Pb, Ag, and, to a lesser extent, Cu (Fig. 4). By far the major contributor to the value of Canada's non-ferrous metal and diamond production has been magmatic Ni-Cu deposits (Fig. 5), whose $Eq372.1 billion metal content represents 44% of Canada's total non-ferrous metal and diamond primary production and 34% of 2005 production with most of this value (65%) being attributable to Ni (Fig. 5). Magmatic Ni-Cu deposits have historically produced (Fig. 4A), and currently account (Fig. 4B) for nearly all of Canada's Ni, Co, and PGE primary output.

Volcanogenic massive sulphide and lode gold deposits have been the mainstay of the Canadian metal mining industry, having supported 153 and 194 mines, respectively, across the country from Newfoundland to Vancouver Island. The $Eq192.3 billion of production makes VMS deposits the second most productive mineral deposit type (Fig. 5), and accounts for 23% of total Canadian historical non-ferrous metal and diamond production and 20% of 2005 production (Fig. 4). This deposit type has produced 68% of Canada's Zn, 52% of its Ag, 40% of its Cu, 32% of its Pb, and 13% of its Au (Fig. 4A), and currently produces virtually all of its Zn, Pb, and Ag (Fig. 4B). Lode gold deposits are Canada's third most valuable mineral deposit type, having produced $Eq131.6 billion of metal, of which 98% is attributable to Au (Fig. 5). Lode gold deposits account for 80% of Canada's Au production. The amount of Au produced (Table 2) is understated because it does not include small mines, especially those of the 19th and early part of the 20th century for which records are sparse, and the amount of byproduct metal is also understated, because most lode gold producers report only the amount of Au.

Porphyry deposits in Canada did not make a significant contribution to Canada's mineral production until the early 1970s, and their $Eq48.5 billion of production is only 5.7% of total Canadian non-ferrous metal and diamond production (Fig. 5; Table 2) but 22% of all Cu production (Fig. 4A). About 70% of the value of production from porphyry deposits is attributable to Cu, 14% to Mo, 13% to Au, and 2.5% to Ag. Production from SEDEX deposits has totaled $Eq40.8 billion (Fig. 5), and supplied 19% of the Zn, 54% of the Pb, and 13% of the Ag (Fig. 4A) produced in Canada to the end of 2005. Mississippi Valley-type deposits have contributed $Eq19.0 billion in production, mainly from the Zn content, and about 12% of both Canada's Zn and Pb production (Fig. 4A).

Total U production from the Athabasca Basin to the end of 2005 was $Eq10.7 billion, about $1.0 billion less than the total amount of U that has been produced in all other parts of Canada (Fig. 5). However, with reserves (Fig. 6) sufficient for another 25 years of production at 2005 rates of mining, production of U from the Athabasca Basin will far surpass production from other areas in the future. Despite the world-leading production and the very high values of the ores, U production from the Athabasca Basin contributed only 11% of Canada's non-ferrous metal and diamond production in 2005, because the quantities of U produced are relatively small. Veins, together with skarn deposits, mined mainly in the early part of the 20th century, have contributed about $Eq10.0 billion in production, about 57% of this value being attributable to Ag (Fig. 5; Table 3). Production of diamonds in Canada began in 1998 and to the end of 2005 had a value of $Eq8.2 billion (Fig. 5). Production of diamonds during 2005 was $1.4 billion or 11% of Canada's total non-ferrous metal and diamond production (Fig. 1).

Reserves

Magmatic Ni-Cu deposits also dominate Canada's non-ferrous metal and diamond reserves as well as past and current production, containing 53% ($Eq82.5 billion) of Canada's $Eq182.3 billion total (Fig. 6; Table3). About 67% of the value Magmatic Ni-Cu reserves is attributable to the Ni content. VMS deposits, with $Eq20.0 billion of reserves, has the second highest reserve value and represents about 13% of the value of Canada's total non-ferrous metal and diamond reserves. Remaining reserves are distributed between Porphyry deposits ($Eq15.6 billion), U deposits of the Athabasca basin ($14.6 billion), Kimberlite diamonds ($Eq11.8 billion), Lode Gold deposits ($Eq9.6 billion), and a small amount in tungsten skarns (<$Eq0.1 billion). Almost 50% the value of VMS reserves is in their Zn content, and 67 % of the value of Porphyry deposit reserves is in their Cu content (Fig.6; Table 3). Lode Gold deposits contain only 54% of Canadian Au reserves (Fig. 6; Table 3). At 2005 rates of production, the reserves for Lode Gold deposits are sufficient for only four more years of mining, which forecasts impending mine closures and decreased production, unless the concerted exploration efforts ($381.6 million in 2005) to find new deposits meet with significant success.

Measured and Indicated Resources

Measured and indicated resources are the inventory from which the next generation of Canada's mines is likely to be developed. The resources are spread over every mineral deposit type (Fig. 7), but many of these resources are in frontier areas and their future development at this time is uncertain. The statistics for this category include historical estimates of resources, which if re-estimated to NI 43-101 requirements may be reclassified differently, such as to inferred resources or to an informal category such as “potential resources”.

Porphyry deposits are the major repository for Canada's un-mined mineral resources, containing $Eq185.3 billion (Fig. 7; Table 3) or 40% of the $Eq463.3 billion of all Canadian mineral resources in this category, including 100% of its Mo, 68% of its Cu, 53% of its Au, and 14% of its Ag, as well as significant quantities of W and Sn. Most of these resources are in British Columbia. Measured and indicated resources of $Eq94.9 billion in Magmatic Ni-Cu deposits and $Eq78.8 billion in VMS deposits represent 20% and 17%, respectively, of Canada's total of this mineral resource category (Fig. 7; Table 3). There are $Eq32.5 billion Zn, Pb and Ag in measured and indicated resources in SEDEX deposits, mainly in theYukon and British Columbia, with most of this value being in their Zn content. Measured and indicated Lode Gold resources of $Eq27.9 billion contain 37% of Canada's Au resources (Fig. 7). Measured and indicated resources of Kimberlite diamonds ($Eq15.6 billion) are mainly in Ekati and in the three deposits currently at the advanced exploration stage (Victor, Snap Lake, Gaché Hue) prior to production decisions which may result in them being reclassified as reserves. Most of Canada's un-mined $Eq15.5 billion mineral resources of MVT deposits are in the western part of Northwest Territories. All other mineral deposit types contribute 3.7 % to the measured and indicated resource category.

Inferred Resources

The statistics for this resource category applies only to those deposits whose mineral resources have been estimated to NI 43-101 requirements. Insomuch as most exploration effort over the past decade has been directed towards diamonds, Au, Ni and U deposits, the proportion of mineral resources in the inferred resources category is valid on ly for the Magmatic Ni-Cu, Lode Gold, Uranium, and kimberlite diamond mineral deposit types.

Magmatic Ni-Cu deposits dominate the inferred resources category (Fig. 8), constituting 47% of the $Eq105.1 billion total (Fig. 8; Table 3). Lode Gold deposits contain $Eg19.5 billion in inferred resources, SEDEX deposits $13.4 billion (the result of a recent re-estimation of resources at Howards Pass), and kimberlite diamonds $9.7 billion (Fig. 8). Volcanogenic massive sulphide, MVT,and Athabasca basin U, deposits all have inferred resources in the $Eq3.9 billion to $Eq4.7 billion range (Fig. 8; Table 3).

Values per Tonne

The average values per tonne statistics for the different resource categories (Figs. 9, 10, 11, and 12) are proxies for the grades of ores. The Athabasca Basin deposits contain the world's richest U ores, with reserves containing a phenomenal average $Eq5,190/t in sufficient quantities for another 25 years of production at 2005 rates of mining. The average equivalent dollars per tonne for magmatic Ni-Cu ores are $Eq272/t for production (Fig. 9) and $Eq294/t for reserves (Fig. 10), which are the highest amongst all base metal mineral deposits types currently being mined. Average grades of VMS ores that have been mined at $Eq174/t is about the same as other Zn-rich underground base metal mineral deposit types (Fig. 9) but, as discussed later, there is a large range from deposit to deposit, both in dollar equivalents of ore per tonne and the relative proportions of different metals.

The low $Eq15.7/t for production (Fig. 9), $Eq13.4/t for reserves (Fig. 10), $Eq28.1/t for measured and indicated resources (Fig. 11), and $Eq18.4/t for inferred resources (Fig. 12), reflect the low grade of porphyry deposits in general. These large low-grade deposits are currently mined only by the low-cost open-pit method, but on-going research into developing underground mining methods and technology that would rival open-pit costs gives hope that in the future porphyry deposits can be mined without the environmental concerns associated with open-pit mining (Morgan, 2005).

The $Eq157.9/t metal content of measured and indicated resources for SEDEX deposits (Fig. 11) is only slightly lower than the $Eq171.1/t content of ores that have been mined, suggesting that at least part of these resources are marginal to being economically mineable, if a suitable surface transportation and power infrastructure were in place. The average $Eq173.8/t for production from MVT deposits is about the same for other deposit types mined for Cu, Zn, and/or Pb by underground methods (Fig. 9), but the average $Eq117.0/t for measured and indicated resources (Fig. 11) is lower, largely because of the influence of the large tonnages but lower grades of the Gayna River deposits.

Unlike metals, the value of kimberlite diamond ores depends on the quality of the diamonds as well as its grade. The average value of ores produced from the Ekati mine has been $253/tonne and that of Diavik $366/tonne. Reserves at Ekati are estimated to have an in situ value of $91/tonne, at Diavik $256/tonne and at Jericho $117/tonne, based on the very tenuous assumptions that the average value of diamonds at the three mines are $133/ct, $80/ct, and $81/ct respectively.

Geological Environments of Mineral Resources

There is increasing acceptance that plate tectonics and the supercontinent cycle operated back into the Archean (e.g. Kerrich and Polat, 2006). The most productive geological environments for the formation of metalliferous mineral deposits are in volcanic arcs and back arcs that were built upon, or accreted to, continental margins during supercontinent assembly (e.g. Barley and Groves, 1992) (Figs. 13, 14). Most of the mineral deposit types, particularly porphyry deposits (Sinclair, 2007) and intrusion-related and epigenetic lode gold subtypes (Dubé and Gosselin, 2007; Hart, 2007) in subaerial arcs, and VMS deposits (Galley et al., 2007a) in submarine arcs and back arcs, are directly related to magmatic and/or associated convective hydrothermal systems (e.g. Lydon, 1996). The age of these deposits (Fig. 16) correspond to periods of subduction, which in the case of deposits formed in oceanic arcs or continental arcs of microcontinents may be up to a few tens of millions of years prior to accretion (e.g. Percival, 2007; van Staal, 2007). The orogenic subtype of lode gold deposits (Dubé and Gosselin, 2007) is related to hydrothermal systems generated by collisional tectono-thermal processes.

Spreading centres in oceanic crust are not highly productive for mineral deposits, even though mid-oceanic spreading centres are the most common site for modern metalliferous hydrothermal deposition. Ophiolites, which generally are oceanic crust generated at back-arc spreading centres (Fig. 14) and obducted onto continents, contain only the relatively small Cyprus-type VMS deposits and podiform chromite deposits (Bédard et al., 2007). However, old oceanic crust, formed during the Paleoproterozoic or earlier, contains Ni-Cu deposits associated with komatiitic lava flows, such as the Archean deposits of the Abitibi Belt and possibly those of the Thompson Belt (Eckstrand and Hulbert, 2007).

Mineral deposit types that form in or on continental crust (Fig. 15) during the long periods of supercontinent cohesion can be divided into two major categories:

1. Mineral deposits of mafic-ultramafic magmas, whose emplacement is along structures that dislocate or perforate continental crust and penetrate the mantle. Most of these structures have their origins in tensile stresses produced by lateral spreading at the head of mantle plumes, which allows the upwelling of mantle magmas into the continental crust (Ernst, 2007). Magmatic Ni-Cu deposits that segregated from these magmas are the major mineral deposit type, but the crustal perforation that produced Canada's most productive deposits of this type was due to a large meteorite impact (Ames and Fallow, 2007; Eckstrand and Hulbert, 2007). Diamondiferous kimberlite diatremes and dykes (Kjarsgaard, 2007) are the other major mineral deposit type in this category.
2. Mineral deposits of intracontinental and epicontinental sedimentary basins. Intracontinental sedimentary basins accumulate in depressions of continental crust caused either by rifting or by crustal warping in the foreland of thrust belts, and epicontinental sedimentary basins are the successors to the rifts along which oceans initially opened. Rifting in these sedimentary basins may be reactivated by far field extensional tectonics related to an approaching subduction zone during the initial stages of the accretionary phase of the supercontinent cycle (Fig. 15). These extensional synsedimentary faults are the conduits for basinal brines to the seafloor to form SEDEX Zn-Pb-Ag deposits (Goodfellow and Lydon, 2007), whereas MVT Zn-Pb deposits (Paradis et al., 2007) are formed by the migrations of basinal brines from epicontinental sedimentary basins into adjacent platformal carbonates in response to tectonic basin inversion during continental accretion. Unconformityrelated U deposits (Jefferson et al., 2007) and diagenetic Cu deposits (e.g. Kirkham, 1996a,b) are likewise formed by the migration of basin or basement groundwaters across a groundwater redox boundary. Paleoplacers (e.g. Roscoe, 1996), the most important source for South Africa's world-leading Au production and for Canada's Elliot Lake former U production, accumulate as heavy mineral concentrations at the edges of sedimentary basins in fluviatile or estuarine sediments.

Geochronology of Canada's Mineral Deposits

The age of a mineral deposit is critical to relating ore formation to tectonic and geological processes. The ages of mineralization for deposits that are coeval with magmatic host rocks (VMS, magmatic Ni-Cu-PGE, porphyry deposits) are relatively well known because of a rapidly expanding database of U-Pb ages of magmatic zircon, particularly the National Geochronological Knowledge Base (www.ims1. ess.nrcan.gc.ca/geochron). The ages of synsedimentary deposits (SEDEX) can be estimated from paleontological dating or by bracketing the stratigraphic horizon hosting the deposit by radiometric dating of any intercalated volcanic rocks. The ages of epigenetic deposits (lode gold and MVT) requires specific dating of gangue, alteration, or ore minerals (Dubé and Gosselin, 2007; Paradis et al, 2007), and as a result of the far fewer geochronological studies of this nature, the age distribution of epigenetic deposits is less well documented than mineral deposits that were formed at about the same time as their host rocks (Figs. 16, 17).

With some caveats, the geochronological distribution of mineral deposits in Canada (Figs. 16, 17) conforms to the timing of global supercontinent cycles (e.g. Hoffman, 1988; McCulloch and Bennett, 1994; Taylor and McLennan, 1995; Rogers and Santosh, 2003; Hawkesworth and Kemp, 2006) and correlate with the age spans of the geological environments described above that these cycles control. The geochronological distribution of VMS deposits (Fig. 16) marks the relatively short periods of supercontinent assembly over the entire span of preserved geological history, but spatially (Fig. 2) are confined to the margins of ancient continents whose growth involved the accretion of oceanic arcs/back-arcs and the construction of submarine continental arcs/back-arcs. Orogens formed by continent-continent collision, such as the Grenville (Figs. 2, 16) (Corriveau et al., 2007) or by intracrustal melting, such as the Taltson-Thelon magmatic zone (Chacko et al., 2000) (Fig. 2) lack a significant VMS resource. Orogenic lode gold deposits, associated with collisional tectonism and its aftermath (Fig. 13, 14) have approximately the same geographic distribution as VMS deposits (Fig. 2), but are generally tens of millions of years younger (Fig. 16) (e.g. Percival, 2007). Porphyry deposits also mark continental arc construction during supercontinent assembly but their incidence, like other high-level deposits (e.g. epithermal Au, Figs. 13, 14), decreases with age (Fig. 16) due to the deepening of the erosion level with time.

The geochronological distribution of some mineral deposit types reflects evolutionary changes to the lithosphere, oceans, or atmosphere that exert an impact on the geological environments in which mineral deposits are formed. Magmatic Ni-Cu deposits in komatiitic lava flows and related sills or dykes, which constitute the majority of Ni-Cu deposits in Figure 16, are confined to rocks older than about 1800 Ma (Eckstrand and Hulbert, 2007), when the Earth's crust was thinner, heat flow higher, and the mantle less depleted (e.g. Taylor and McLennan, 1995). SEDEX deposits (Fig. 17) globally are confined to sedimentary basins younger than 1800 Ma (i.e. on the Nuna or later supercontinents). MVT deposits, which, like SEDEX deposits, are also genetically related to the migration of basinal brines of marine sedimentary basins (Paradis et al., 2007) are nearly all of Phanerozoic age (Fig. 17). The key explanation to this difference in geochronological distribution may be related to the erosion-prone geological setting of MVT deposits in the forelands of thrust and fold belts, which has resulted in the destruction of Proterozoic deposits. Placer U deposits are known only on the Kenorland supercontinent when the atmosphere lacked significant free oxygen.

Distribution of Mineral Deposits in Canada

The geographical distribution of all mineral deposits with respect to orogens and continental interiors of supercontinental cycles are shown in Fig. 2 and a summary of resources by geological environment and supercontinent cycle in Table 4. Mineral deposits of orogens have contributed $Eq417.8 billion (49.4%) of production and account for $Eq843.1 billion (53.6%) of total resources (Table 4). Exclusive of the deposits related to the Sudbury meteorite impact structure (which are not related to the supercontinent cycle) the proportions rise to 81.2% of production and 74.4% of total resources. The distribution of accreted oceanic arcs, continental arcs, and major structural dislocations at continental margins are therefore the main control on the distribution of the bulk of mineral deposits.

Kenorland

Fragments of a single Kenorland (Williams et al., 1991), or more than one smaller Archean- Paleoproterozoic supercontinent( s) such as Sclavia and Superia (Bleeker, 2003), are preserved as the Superior, Slave, Churchill (now Rae, Hearne, Wyoming, and Eastern Churchill subprovinces), Nain, and Makkovik geological provinces and form the central core of Canada's land mass (Fig. 2). These Archean cratons consist of ca. 2700 to 2800 Ma oceanic arcs and backarc basins that aggregated, together with fragments of ca. 3400 to 2800 Ma continental crust (e.g. David et al., 2003) possibly derived from an earlier Ur supercontinent (Rogers, 1996) via successive collisional events over the ca. 2700 to 2650 Ma time interval (e.g. Bleeker and Hall, 2007; Percival, 2007). Continental arcs and associated back-arc basins formed at the margins of the oceanic arc nuclei both before and during collisional events, and shed detritus to form sedimentary basins both between and within volcanic arcs. Synand post-orogenic plutons, dominantly of tonalite, granodiorite, and granite (TGG) composition, invaded the volcanosedimentary complexes of the newly aggregated crust to become the dominant lithology over large areas. Most tectonic and magmatic activity came to an end by about 2650 Ma (e.g. Bleeker and Hall, 2007; Percival, 2007). The geological architecture of Kenorland is thus very different from later supercontinents in that it may be viewed as an aggregation of newly formed orogens over its entire area, whereas later supercontinents that consist of a cratonic interior and orogens are restricted to linear to arcuate belts along their contemporary margins.

By far the economically most productive geological environments of the Archean provinces are the greenstone belts, which represent the remains of the tholeiitic or calc-alkaline volcanic arcs that have been preserved between tonalitetrondhjemite- granodiorite (TTG) intrusions and not buried by sedimentary basins. These greenstone belts have produced $Eq115.8 billion from lode gold deposits and $Eq102.6 billion from VMS deposits, which together represent 92.1% of production from Kenorland mineral deposits and separately account for 88.0% and 53.4%, respectively, of total Canadian production from these deposit types. The most productive area is the Abitibi greenstone belt in the Superior Province (Card and Poulsen, 1998) of Quebec and Ontario (Fig. 2), but lode gold and VMS deposits occur elsewhere, particularly in the western part of the Superior Province and the Slave Province (Fig. 2). If there is a geological reason for the high metal endowment of the Abitibi belt in comparison to other Archean greenstone belts, it needs to be determined in order to evaluate whether other Archean greenstone belts of Canada have a comparable potential. Magmatic Cu-Ni deposits in komatiite lavas of back-arc basins (Eckstrand and Hulbert, 2007), particularly of the Timmins area, Ontario, and the Val d'Or area, Quebec (Fig. 2), and porphyry deposits (Sinclair, 2007) in the general Chibougamau area, Quebec, and the Timmins and Matachewan areas, Ontario, have produced $Eq2.6 billion and $Eq2.1 billion, respectively, and together account for 1.3% of production from Kenorland mineral deposits.

Deposits associated with anorogenic mafic-ultramafic intrusions include the 2738 Ma Lac des Isles PGE-rich deposit in western Ontario, the low-grade and large-tonnage Dumont sill in western Quebec, and the closed Rankin Inlet mine in Nunavut (Eckstrand and Hulbert, 2007). Perhaps the Ag-rich veins of the highly productive Cobalt district in eastern Ontario (Ruzicka and Thorpe, 1996a), which are associated with the rifting event marked by the ca. 2200 Ma (Andrews et al., 1986) Nipissing diabase sills (Fig. 2), should also be included in this category. Collectively, these deposits have contributed $Eq6.3 billion or 2.7% of Kenorland mineral production. Mineral deposits of Kenorland sedimentary basins consist mainly of the ca. 2450 Ma uraniferous paleoplacers of Elliot Lake (Roscoe, 1996) at the base of the Huronian Supergroup in western Ontario, which have produced $Eq7.7 billion or 3.3% of Kenorland mineral production. The general lack of a platformal cover on Archean cratons led Hoffman (1990) to suggest that the assembly of these cratons produced an anomalously thick continental keel, which may give the Canadian Shield its prospectivity for diamonds (Kjarsgaard, 2007).

Nuna

Break-up of the Archean supercontinent occurred during 2170 to 1920 Ma and assembly of the Nuna supercontinent was completed by about 1830 Ma (Hoffman, 1988, 1989) along the Torngat, New Quebec, Ungava, Trans-Hudson, Taltson-Thelon, and Wopmay orogenic belts (from east to west, Fig. 2) (St-Onge and Lucas, 1996). The most productive of these Nuna orogens is the complex Trans-Hudson Orogen (Corrigan et al., 2007) containing the magmatic Ni- Cu deposits of the Thompson belt of Manitoba hosted by 1883 Ma komatiitic sills of a rifted foreland margin (Eckstrand and Hulbert, 2007; Layton-Matthews et al., 2007) and VMS deposits of the Flin Flon and Snow Lake mining districts in Manitoba and Saskatchewan (Galley et al., 2007b) in the Reindeer Zone, a collage of of Archean crustal fragments, 1920 to 1869 Ma oceanic arcs, and 1870 to 1830 post-accretion continental arcs.

The rifted continental margin of the Ungava Orogen, which represents a ca. 1800 Ma arc-continent collision (St. Onge and Lucas, 1996) contains the 1918 to 1883 Ma magmatic Ni-Cu in komatiitic sills that are being mined in northern Quebec (Lesher, 2007) (Fig. 2). The New Quebec Orogen (Fig. 2), forming the zone between the Superior Province and the southeast Churchill Province, contains small magmatic Ni-Cu-PGE deposits in sills of a ca. 2170 Ma sediment-sill complex associated with rifting of the Superior Craton, and small VMS deposits in a younger ca. 1880 Ma sediment-volcanic sequence (Wardle and Hall, 2002) (Fig. 2). Low-grade U deposits are hosted by felsic volcanics of the 1805 to 1860 Ma Aillik Group (Gandhi and Bell, 1996) that formed during the 1700 to 1900 Ma Makkovikian Orogeny marking the collision of the Makkovik Province with the Nain Province.

The 1910 to 1860 Ma calc-alkaline plutonic rocks of the Torngat Orogen (St-Onge and Lucas, 1996) and the 2000 to 1900 Ma, highly deformed, dioritic to granitic plutons of the Taltson-Thelon magmatic zone (Hoffman, 1988) are both interpreted to be the roots of a magmatic arc and do not preserve the shallow levels of arcs that are the most favourable for the formation of mineral deposits. The Taltson-Thelon magmatic zone may, alternatively, reflect intracrustal melting and not a continental suture between the Rae subprovince in the east and the Slave Province in the west (Chacko et al., 2000; De et al., 2000). The Wopmay Orogen preserves the western rifted Proterozoic passive margin (Coronation Supergroup) of the Slave Province with subsidence beginning about 1970 Ma (Hoffman, 1989), which was translated eastwards over the Slave craton as a fold and thrust belt by the collision of the 1950 to 1910 Ma Hottah arc and was followed by development of the 1880 to 1860 Ma calc-alkaline Great Bear magmatic arc above an east-dipping subduction zone. The Great Bear magmatic zone contains Canada's two principal deposits suggested to be iron oxide copper-gold type (Corriveau, 2007) (Fig. 2).

Several major metallogenic events are associated with episodic rifting of the Nuna supercontinent (Fig. 17). The magmatic Cu-Ni deposits include Voisey's Bay (Naldrett and Li, 2007), hosted by 1290 to 1340 Ma troctolite intrusions associated with the anorogenic Nain plutonic suite, those of the 1108 Ma Crystal Lake gabbro, and those in the Marathon area that are associated with the mid-continental rift. Although there are a number of Paleoproterozoic and Mesoproterozoic sedimentary basins preserved from this time period, only two have produced mineral deposits of economic significance. The ca. 1500 to 1320 Ma Belt- Purcell sedimentary basin of southeastern British Columbia (Lydon, 2007) is a sedimented continental rift that hosts the large Sullivan SEDEX deposit. The ca. 1750 to 1650 Ma Athabasca Basin (Jefferson et al., 2007) has produced the very rich unconformity-associated U deposits of Saskatchewan, which formed by the circulation of basinal and basement fluids at 1500 and 1350 Ma, times which coincide with continental extensional events (Fig. 17).

By far the most significant metallogenetic event in the Nuna supercontinent was the 1850 Ma meteorite impact that produced the Sudbury structure which contains 64.2% of Nuna's $Eq686.6 billion and 28.0% of Canada's $1574 billion total non-ferrous metal and diamond resources. The timing of the impact during accretion of Nuna may have been a factor in its prodigious Ni-Cu endowment.

Although major mineral deposit types of the orogens of Nuna (VMS, lode gold, and komatiite-associated Ni-Cu deposits) are the same as for the greenstone belts of Kenorland, their values (Table 4) and relative proportions are very different. VMS, lode gold, and Cu-Ni deposits constitute 33.2%, 4.8%, and 59.8%, respectively, of Nuna's $Eq125.2 billion total resource in orogens, whereas the comparable statistics for Kenorland are 44.0%, 49.9%, and 2.4%, respectively, of a $322.6 billion total resource in greenstone belts. The large increase in the ratio of komatiitic Ni-Cu to VMS resources but major decrease in ratio of lode gold to VMS resources obviously reflect a dramatic change to the architecture of and/or to the processes of continental accretion between the Archean and the Paleoproterozoic. Another major change from the Archean to Paleoproterozoic that continues into younger supercontinents is the increase in the relative amount of resources contained in supracrustal sedimentary basins (Table 4), presumably mainly due to the increase with decreasing age of the area of supracrustal rocks that have been preserved (Fig. 2).

Rodinia / Laurentia

Accretion continued intermittently along the southeastern margin of the Nuna supercontinent from the end of the Paleoproterozoic to the end of the Mesoproterozoic (e.g. Zhao et al., 2004), culminating with the 1250 to 980 Ma (Rivers et al., 2002) arc-continent and continent-continent collisions of the Grenville Orogeny to form the Rodinia supercontinent. The earliest of three major accretionary events is represented by 1677 to 1646 Ma calc-alkaline to alkaline plutonism and volcanism of the Trans-Labrador arc and related 1650 to 1620 Ma trimodal mafic-anorthositicmonzogranitic magmatism on which were developed 1600 to 1510 Ma successor sedimentary basins (Wakeham Bay Group and correlatives) (Gower and Krogh, 2002). The second major event involved the accretion of a ca. 1500 Ma oceanic arc as the Quebecia terrane (Martin and Dickin, 2005) and a 1514 to 1493 Ma granitic continental arc of the Pinwarian Orogeny (Gower and Krogh, 2002). Post- Pinwarian 1450 to 1250 Ma continental arc volcanics and back arc or intracontinental sedimented rifts with associated carbonate platforms, occurring mainly in the western part of the Canadian portion of the Grenville Orogen, are host to small VMS and SEDEX/MVT deposits (Gauthier and Chartrand, 2005). Important ilmenite deposits (not compiled here) are associated with 1180 to 950 Ma (Davidson, 1998) anorthosites of western Quebec.

Rifting, which led to the break-up of Rodinia and the spawning of Laurentia, started at about 730 Ma in western Canada and 615 Ma in eastern Canada. Neoproterozoic sedimentary basins that filled these rifts are preserved at the western, northern, and eastern margins of what was to become Laurentia. The major mineral deposit of these basins occur in western Canada, notably the diagenetic Cu redstone deposit of western Northwest Territories near the base of the Windemere Supergroup (Figs. 2, 17) and possibly the highly metamorphosed Zn-Pb deposits of presumed Neoproterozoic age in the Shuswap complex of southern British Columbia (Höy, 1982). Final continental separation of Siberia from Laurentia probably did not take place until the Cambrian (Sears and Price, 2000, 2003), but rifting of the western Laurentian continental margin with associated SEDEX deposits continued through the Paleozoic (Fig. 17) until Devonian 390 to 320 Ma arc magmatism and Early Mississippian back-arc spreading (Nelson and Colpron, 2007). This semi-permanent rifting of the western margin of Laurentia illustrates that epicontinental rifting associated with continental separation may be difficult to distinguish from epicontinental rifting caused by far-field extensional tectonics prior to arc accretion, and opens to debate the geotectonic setting of SEDEX deposits in general.

The total non-ferrous metal and diamond resources of Rodinia are very small compared to other supercontinental cycles, mainly because of the extremely small inventory for deposits of its orogens. A major reason for this may be that the high-grade metamorphism generally prevalent throughout the Grenville Orogen may have hindered the recognition of geological environments and hydrothermal alteration patterns favourable for mineralization (Corriveau et al., 2007).

Pangea

The assembly of Pangea, in contrast to the assembly of older supercontinents, did not involve significant generation of new continental lithosphere (e.g. Kemp et al., 2006). The Appalachian Orogen (van Staal, 2007) records the rifting of Rodinia starting at 615 Ma; the closure of an arm of the Iapetus Ocean with the docking of the Avalonia terrane of Gondwanaland origin at ca. 425 Ma; the closure of the Rheic Ocean with the accretion of the Meguma terrane, also of peri-Gondwanaland origin at ca. 395 Ma; and the final collision of Laurentia and Gondwanaland during the Carboniferous-Permian to form the Pangea supercontinent. By far the most important mineral production from the Appalachian Orogen (Table 4) has come from VMS deposits of accreted 485 to 435 Ma arc and back arc, and 510 to 477 Ma ocean tract environments that formed within the realm of the Iapetus Ocean. The most important are those of the Bathurst mining camp of New Brunswick (Goodfellow, 2007a) in the 480 to 455 Ma Tetagouche-Exploits back arc of peri-Gondwanaland (Ganderian) origin (van Staal, 2007) and deposits in the central mineral belt of Newfoundland of peri-Laurentia origin, including the Buchans district in the 481 to 460 Ma Annieopsquotch accretionary tract and the Ducks Pond deposit (currently entering production) in the 513 to 486 Ma Penobscot arc/back arc (van Staal, 2007). A modest production has come from lode gold deposits, notably the Hope Brook mine of Newfoundland in an accreted Neoproterozoic continental fragment, deposits of the Meguma area of Nova Scotia (Sangster and Smith, 2007) associated with ca. 370 Ma orogenic tectonism and magmatism (van Staal, 2007), and smaller deposits associated with ca. 440 to 420 Ma Salinic and ca. 420 to 390 Ma Acadian tectonism and magmatism, such as those of the Baie Verte Peninsula in Newfoundland (Sangster et al., 2007). Porphyry deposits are associated with Middle Devonian to Early Carboniferous Neo-Acadian granites, especially the Gaspé porphyry Cu deposit and associated skarns of Quebec and the Mount Pleasant Sn-W porphyry of New Brunswick, and small magmatic Ni-Cu deposits occur in Early Devonian layered mafic-ultramafic intrusions in New Brunswick. The economically important asbestos deposits (not compiled here) of the eastern townships of Quebec occur in 489 to 477 Ma ophiolites that formed during the separation of the Dashwoods microcontinent from the Laurentia supercontinent and later obducted onto the supercontinent's margin at ca. 425 Ma (van Staal, 2007).

The northern margin of Laurentia was mainly passive from the beginning of its rifting at 723 Ma and accumulated up to 6000 m of Neoproterozoic to Silurian sediments prior to accretion of the Mesoproterozoic-Silurian Pearya microcontinent and the subsequent late Silurian – early Devonian Boothia uplift (Dewing et al., 2007). Rocks of arc or oceanic tract affinity, but without mineral deposits, are known only in the accreted Pearya fragment. Similarly, at the western margin of Laurentia, the evidence for offshore or continentmargin arcs prior to Devonian time is very limited, and it too was the site of continuous sediment accumulation, albeit with semi-continuous rifting, from the Neoproterozoic to the beginning of arc activity of the Cordilleran Orogeny in the Middle to Late Devonian (Nelson and Colpron, 2007). These epicontinental sedimentary basins contain 62.7% of Canada's total SEDEX-type mineral resource, notably in the Selwyn Basin of Yukon (Goodfellow, 2007b), and the Kechika trough and Kootenay arc of British Columbia (Fig. 2). Their coeval platformal sedimentary sequences, together with successor sedimentary basins on the Appalachian Orogen, contain 92.8% of Canada's total MVT mineral resource, notably in the Polaris deposit of Nunavut, the Pine Pont deposits of Northwest Territories, and deposits along the western margin of the Cordillera (Fig. 2). The ratio of mineral resources in sedimentary basins to mineral resources of orogens for the Pangea continental cycle is three times higher than for the Nuna supercontinent cycle (Table 4), and is probably more a reflection of the relative amounts of preservation of sedimentary basins in the two supercontinent cycles (Fig. 2) than global evolution of geological processes. The mineral resources of Pangean sedimentary basins are dominated by Zn and Pb, in contrast to U for Nuna, which, considering that the world's major U deposits are all of Proterozoic age (Jefferson et al., 2007), is largely a reflection of increasing free-oxygen levels with time. It is debatable whether MVT deposits (Paradis et al, 2007) should be considered to be among the earliest (because they are generally thought to have been formed by the migration of basinal brines from sedimentary basins of ‘passive' margins in response to uplift by a developing orogen) or among the latest (because they are products of sedimentary basins formed prior to the beginning of new accretion) deposits of a supercontinent cycle. Insomuch as both the break-up of Pangea with the opening of the Atlantic and the earliest accretion of exotic terranes in the Cordillera occur in the late Permian, MVT deposits formed earlier are here considered to be Pangean deposits (Fig. 17).

North America

The North America cycle (Figs. 16, 17) cannot be regarded to be of the same geotectonic significance as the Nuna or Rodinia supercontinent cycle because it had not yet culminated in the assembly of a supercontinent. Mineral resources are dominated by deposits of the Cordilleran Orogen ($Eq347.2 billion) with kimberlite diamonds ($Eq54.8 billion) being the next most important resource (Table 4). To the end of 2005, porphyry deposits (Sinclair, 2007) have contributed 62.4% of the $Eq66.4 billion of production from the Cordilleran Orogen, followed by lode gold (19.4%), VMS deposits (11.9%), and veins, skarns, etc. (6.4%). The same deposit types account for 83.8%, 5.5%, 7.4%, and 2.5%, respectively, of the $Eq347.2 billion of total non-ferrous metal and diamond resources, the remaining 0.8% by Ni-Cu deposits. The preponderance of porphyry deposits and intrusion-related and epithermal lode gold deposits is a reflection of the youth of the orogen and the preservation of high-level deposits of subaerial arc magmatism. The $Eq26.6 billion of total VMS resources is substantially less than for both Nuna and Pangea, and perhaps reflects the smaller proportion of oceanic arcs compared to continental arcs in the Cordilleran Orogen (Fig. 2).

Volcanogenic massive sulphide deposits of the Findlayson Lake area of southern Yukon (Peter et al., 2007), the Tusequah Chief deposit in northwest British Columbia, and deposits in the Eagle Bay assemblage in southeastern British Columbia (Fig. 2) are associated with arc-related bimodal 360 to 350 Ma magmatism developed on both the continental margin and the attenuated crust of the peri-Laurentia terranes. These peri-Laurentia terranes were formed by the separation of ribbon continents during the period of rifting with which the youngest mid-Devonian SEDEX deposits of the Selwyn Basin and Kechika trough are associated (Nelson and Colpron, 2007). The ca. 370 Ma Myra Falls VMS deposits on Vancouver Island in the Devonian Sicker Group, although of similar age, belong to Wrangellia, a terrane with peri-Siberian linkages, accreted to Intermontane terranes during mid-Jurassic and to North America prior to the Eocene (Nelson and Colpron, 2007) (Fig. 2). Similarly, the very large 217 Ma Windy Craggy VMS deposit of northeastern British Columbia and the high-grade Greens Creek VMS deposit of Alaska are hosted in a Late Triassic rift of the Alexander terrane, also with peri-Siberian linkages (Nelson and Colpron, 2007).

Most of the porphyry and epithermal, intrusion-related, and mesothermal lode gold deposits are related to arc magmatism and collisional tectonics of the Laurentian margin. Closure of marginal basins and accretion of the peri- Laurentia terranes began during the late Permian to early Triassic with the accretion of the innermost pericratonic terranes (Slide Mountain, Quesnel, and Yukon-Tanana), but voluminous arc magmatism, including the Takla and Nicola groups, did not begin until the late Triassic. Early Jurassic arcs were superimposed on Triassic architecture and in Quesnel and Yukon-Tanana terranes, and migrated eastwards towards the continent. In the Stikine terrane, Lower Jurassic volcanogenic strata of the Hazelton Group are widespread. Late Triassic to Early Jurassic, ca. 210 to 185 Ma (Fig. 16) Cu-Au and Cu-Mo porphyry deposits of Stikine and Quesnel terranes are the most important group of deposits in British Columbia (Fig. 2) and include producers such as Highland Valley, Gibraltar, Mt. Polley, and Kemess. This metallogenic province extends into the Yukon-Tanana terrane of Yukon (Fig. 2).

In mid-Jurassic time, the Stikine crustal block collided with the already-accreted Quesnel terrane and western North America, terminating the Quesnel and eastern Stikine (Hazelton) arcs, and trapping the Cache Creek accretionary prism and ocean floor between them (Nelson and Colpron, 2007). Just prior to collision, the narrow Eskay rift developed in the Stikine crustal block and became filled with clastic sediments and a ca. 175 Ma bimodal volcanic suite that hosts the Au-rich Eskay Creek VMS deposit.

Following the mid-Jurassic accretionary event, the accreted terranes and epicontinental miocline were tectonically translated eastwards over the cratonic margin, forming a thickening crust on which later Jurassic through Tertiary arcs were built. Four major metallogenic events are associated with these Jurassic through Tertiary arcs. Late Jurassic- Early Cretaceous plutonism produced the 140 Ma Endako porphyry Mo deposit, which is Canada's main source of Mo. The mid-Cretaceous period of 130 to 90 Ma produced the first plutons making up the Coast Plutonic Complex, and a cluster of younger 97 to 92 Ma plutons that gave rise to porphyry Au deposits such as Brewery Creek in Yukon (Hart, 2007); the tungsten skarn deposits of Cantung and Mactung near the Yukon-Northwest Territories boundary (Fig. 2); the Pb-Zn veins of the Keno Hill district; and the Zn-Pb replacements of the Sa Dena Hes deposit of Yukon. One of the largest lode Au resources in the Cordillera, the Bralorne Pioneer mesothermal vein deposit, is associated with mid Cretaceous thrusting. Late Cretaceous 90 to 65 Ma plutons produced significant porphyry Au deposits in Alaska, the 73 Ma Casino porphyry Cu-Mo-Au deposit, the 70 Ma Ruby Creek porphyry Mo deposits in Yukon, and the currently producing 82 Ma Huckleberry porphyry Cu-Mo deposit in central British Columbia. Porphyry Mo deposits were the most common metallogenic expression during 65 to 37 Ma plutonism and volcanism, and include the past-producing Bell and Granisle deposits, and the coastal Kitsault deposit. The 58 Ma Logtung porphyry W-Mo deposit, located near the British Columbia-Yukon border, also belongs to this metallogenic episode. The youngest Porphyry deposit in the Canadian Cordillera is the 37 Ma Catface Cu-Mo deposit on Vancouver Island (Sinclair, 2007). Epithermal lode gold deposits, such as the Grew Creek deposit in Yukon, formed during this 65 to 37 Ma time period, which coincided with 430 km dextral movement along the Tintina fault system. Dextral fault movement, mainly on the Queen Charlotte fault system, and the formation of the Cinola epithermal lode gold deposit on Graham Island (Fig. 2) were the main tectonic and metallogenic events since 37 Ma in the Canadian Cordillera, after which the magmatic arcs shifted mainly to the Aleutian arc of Alaska (Nelson and Colpron, 2007).

The distribution of the various mineral deposit types is illustrated here as a series of maps (e.g. Fig. 18) showing their location with respect to the dominant geological environment of supercontinent cycles and equivalent billion dollar values of the different categories of resources. In order to avoid excessive superposition of the pie diagram symbols on these maps, deposits of the same type and approximately the same age occurring in the same area have been grouped into districts. On each map, only the ten or so districts (or in some cases single isolated deposits) with the greatest values are labeled.

Magmatic Ni-Cu-Platinum Group Element Deposits

Geological Contexts and Distribution

Magmatic Ni-Cu-PGE deposits consist of sulphides associated with mafic and ultramafic igneous rocks whose magmas originate in the upper mantle. The orebodies originate as segregations of Fe sulphide melts from the magma that, because of their high density, have gravitationally settled and concentrated near the base of the magma body (Barnes and Lightfoot, 2005; Eckstrand and Hulbert, 2007). Economic deposits are most likely to occur if the magmas have been contaminated with crustal sulphur (Eckstrand and Hulbert, 2007) and, for komatiite-hosted deposits, are in the magnesium- rich part of their compositional range (Barrie et al., 1993). The main economic commodities are Ni, Cu, and platinum group elements, particularly Pd and Pt. The orebodies are classified into two main types, depending on whether Ni-Cu or PGE are the main economic commodities, and into subtypes depending on their geological setting (Eckstrand and Hulbert, 2007).

Astrobleme-impact melt sheet: The basal part of the 1850 Ma meteorite-impact melt sheet of the Sudbury Igneous Complex (Ames and Farrow, 2007) is the only example of this subtype in the world and contains about 74% of Canada's magmatic Ni-Cu total resources. Its original 200 km wide crater was near the boundary of ca. 2711 Ma Neoarchean gneisses to the north and ca. 2450 Ma volcanosedimentary rocks of the Huronian Supergroup to the south (Fig. 8). This unique event was very fortuitous for Canada's Ni endowment, with Sudbury ores contributing 89% of production, 60% of 2005 reserves, 34% of measured and indicated resources, and 74% of inferred resources of the magmatic Ni-Cu type of mineral deposit in Canada (data in Appendix 1, DVD).

Komatiitic volcanic flows and related intrusions: Paleoproterozoic komatiitic flows and associated intrusions of the 1883 Ma Thompson Nickel Belt of Manitoba (Layton- Matthews et al., 2007) and the 1918 Ma Raglan Horizon of the Cape Smith-Wakeham Bay belt in northern Quebec (Lesher, 2007) (Fig. 18) constitute the second most productive group of magmatic Ni-Cu deposits in Canada, contributing, respectively, 8.3% and 0.8% of the production, 9.1% and 9.0% of the reserves, and 10.6% and 1.5% of the measured and indicated resources. Magmatic Ni-Cu deposits of Archean komatiitic flows are most common in the Abitibi greenstone belt of Ontario and Quebec (Fig. 18), and some, such as the Alexo, Langmuir, Marbridge, Redstone, and Texmont deposits, have been mined. However, production from these deposits has been relatively minor, amounting to about $Eq0.57 billion or 0.15% of the total production from Canadian magmatic Ni-Cu deposits. A large resource of Ni is contained in the Dumont Sill (Fig. 18) but at a very low grade of 0.5% Ni.

Ni-Cu rift-associated mafic sills and dykes: The 1108 Ma Crystal Lakes gabbro (Fig. 18) in western Ontario, which is probably a northern extension of the Duluth Complex of Minnesota (Eckstrand, 1996), is Canada's only example of a magmatic Ni-Cu deposit associated with rifting and flood basalts. The 1270 Ma Muskox intrusion and associated Coppermine flood basalts in the Slave Province of Nunavut, though of the right geological environment, has so far not revealed substantial Ni-Cu sulphide segregations.

Ni-Cu in other mafic/ultramafic intrusions: The Voisey's Bay deposit (Naldrett and Li, 2007) came into production during 2005, and contains 19.5% of the equivalent dollar metal content of reserves and 14.7% of the equivalent dollar value of measured and indicated resources of Canadian magmatic Ni-Cu deposits. The deposit is associated with 1290 to 1340 Ma troctolites of the anorogenic Nain Plutonic Suite in Labrador (Fig. 18) that were emplaced at the 1850 Ma collisional contact between the Archean Nain Province in the east and the Churchill (Rae) Province to the west (Eckstrand and Hulbert, 2007).

Magmatic Cu-Ni deposits associated with tholeiitic intrusions are usually hosted by an ultramafic phase. The deposits range in age from Archean to Mesozoic and have been found across Canada from the 396 Ma St. Stephen deposit in New Brunswick in the east to the 232 Ma Wellgreen and Canask deposits in the west. The Proterozoic Lyn Lake deposit in Manitoba, with about $Eq3.1 billion of production, and the Archean Montcalm deposit in the Abitibi belt near Timmins (Fig. 18), with about $Eq0.2 billion in production and $Eq0.9 billion in reserves, are the most notable examples of this mineral deposit subtype. The Ferguson Lake deposit in Nunavut (Fig. 18), which has the largest single Ni resource in Canada outside of mining areas, appears to be of the tholeiite intrusion type (Carter, 2006).

PGE magmatic breccias of mafic/ultramafic stocks and sills: The Lac des Isles deposit in western Ontario (Fig. 18) is Canada's only deposit that has been mined primarily for its PGE content, consisting mainly of Pd, although subordinate Pt, Ni, and Cu are also produced. The deposit is associated with a 2738 Ma multiphase stock, one of a 30 km diameter ring of similar intrusions in the area.

There are no examples of reef-type or stratiform deposits of well layered, differentiated mafic/ultramafic intrusions in Canada, for which the deposits of the Bushveld Complex of South Africa are the prime examples of this PGE subtype.

Economic Context and Statistics

Magmatic Ni-Cu deposits provide most of the world's Ni supply, though Ni laterite deposits formed by the weathering of ultramafic rocks will probably in time become the main source of Ni (Eckstrand and Hulbert, 2007). The magmatic Ni-Cu mineral deposit type is extremely important to Canada, having produced ores with $Eq372.1 billion metal content (Figs. 5, 18) or about 44% of all non-ferrous metal and diamond production in Canada. Most of this value (65%) is attributable to Ni (Fig. 5) with 15% coming from Cu, 11% from PGE (Pt+Pd), and 8% from Co. Magmatic Ni- Cu deposits have historically produced (Fig. 4A) and currently account (Fig. 4B) for nearly all of Canada's Ni, Co, and PGE primary output. During 2004, the Ni alone produced from magmatic Ni-Cu deposits accounted for 15% of the value of Canada's total non-fuel mineral production (Fig. 1). Combined with all PGE and Co production, and about 28% of all Cu production, the proportion contributed by magmatic Ni-Cu deposits rises to about 21%. The Ni production is about 12% of the world's 2004 Ni supply, making Canada the third most important Ni producer (McMullen and Birchfield, 2005).

Magmatic Ni-Cu deposits contain a greater value of economic commodities than any other mineral deposit type in Canada in all mineral resource categories (Figs. 5, 6, 8), except in the measured and indicated resource category which is dominated by porphyry deposits (Fig. 7). As a proportion of Canada's total non-ferrous metal and diamond resources, magmatic Ni-Cu deposits comprise 45% ($Eq82.5 billion) of reserves, 21% ($Eq95.0 billion) of measured and indicated resources, and 51% ($Eq49.7 billion) of inferred resources (Fig. 18).

The main economic attraction of magmatic Ni-Cu deposits is the high average value of the ores, with about 65% of this value, on average, being in the Ni content (Figs. 9, 10, 11). The weighted average values per tonne for magmatic Ni-Cu deposits are $Eq272/t for production (Fig. 9) and $Eq294/t for reserves (Fig. 10). The lower $Eq135/t for measured and indicated resources (Fig. 11) and $Eq280/t for inferred resources (Fig. 12) are due to the lower grade resources of undeveloped deposits such as the Dumont Sill in Quebec. The average value per tonne of ores milled (Fig. 9) or in reserves (Fig. 10) is the highest for all mineral deposit types, except for the high-grade U ores of the Athabasca Basin and some high-grade Ag veins. Production from individual districts range from a low of $Eq41/t for the open pit Lac des Iles Pd-Pt deposit (but note that this value is still much higher than most porphyry open pit mines) to $Eq599/t for the recently opened Voisey's Bay mine (where, as is common practice, the higher grade ores are mined first). Ores from currently producing underground mines have a metal content of more than $Eq220 (Fig. 19A). The dollar equivalent per tonne of metal content of reserves (Fig. 19B) are approximately the same as for production (Fig. 19A), with the exception of the 50% increase in the value for Lac des Isles reserves ($Eq73/t), which includes a higher grade resource to be mined by underground methods. The dollar equivalent of metal content of measured and indicated resources (Fig. 19C) have a very high value of in excess of $Eq300/t for all producing districts with the exception of the Thompson district ($Eq104/t) and the open pit resources at Lac des Isles ($Eq43/t). The measured and indicated resources for most other magmatic Ni-Cu deposits that are not being mined are in the range of $Eq100/t to $Eq150/t (Fig 19C). This is about $Eq50/t higher than for other massive sulphide deposits such as VMS deposits, which are also most commonly mined by underground methods, making the magmatic Ni-Cu deposits a potentially more attractive exploration target than the more common VMS type of deposit.

VMS Deposits

Geological Contexts and Distribution

Volcanogenic massive sulphide deposits are lenses of Fe, Cu, Zn, and sometimes Pb sulphides, usually with valuable amounts of Ag and Au, that were formed on the seafloor by hot springs on and around submarine volcanoes (Galley et al., 2007a). The amount of sulphide in a single deposit, which may consist of several lenses, averages between 5 and 10 Mt depending upon the VMS subtype, but ranges from tens of thousands to hundreds of millions of tonnes (Galley et al., 2007a). VMS deposits are hosted by submarine volcanic rocks, especially lavas or volcaniclastic sediments of felsic compositions. This spatial association of VMS deposits with felsic volcanic centres is illustrated, for example, by the Abitibi Belt (Fig. 2) where felsic volcanics, although forming only about 6% of the total volume of volcanic rocks, host about 90% of the ore tonnage (Barrie et al., 1993). Volcanogenic massive sulphide deposits clustering around these felsic volcanic centres, which average about 30 km in diameter (Sangster, 1980; Galley et al., 2007a), form distinct mining districts containing ten or more deposits, such as at Noranda (Gibson and Galley, 2007), Matagami, and Bathurst (Goodfellow, 2007a) districts (Fig. 2). Volcanogenic massive sulphide districts associated with felsic volcanic centres are likely the submarine equivalent of subaerial porphyry systems with the bulk of the economic metals supplied by magmatic hydrothermal fluids (Lydon, 1996). The leaching of metals from footwall rocks by convection of heated seawater, the prevalent genetic model for VMS deposits (Franklin et al, 2005; Galley et al., 2007a), probably supplied only a minor proportion of metals in these geological settings. However, convection of seawater formed the overprint of hydrothermal alteration typical of VMS deposits (Galley et al., 2007a) and supplied all the metals for convection systems driven by the heat of anhydrous magmas, such as Cyprus-type VMS deposits of back-arc spreading centres (Fig. 14).

A total of 153 VMS deposits have been mined in all provinces and territories of Canada with the only exceptions being Prince Edward Island and Alberta. Their distribution (Fig. 20) reflects the distribution of ancient orogens (Fig. 20), particularly 2600 to 2800 Ma volcanic belts of the Archean Superior Craton of Quebec and Ontario, and Slave Craton of Nunavut and Northwest Territories; 1800 to 1900 Ma volcanic arcs of the Trans-Hudson Orogen in Manitoba and Saskatchewan; 460 to 500 Ma volcanic belts of the Appalachian Orogen in New Brunswick, Newfoundland, and the eastern townships of Quebec; and 130 to 390 Ma volcanic belts of the Cordilleran Orogen in British Columbia and Yukon (Figs. 16, 20).

Over half of Canadian production from VMS deposits has come from Archean rocks (Fig. 21). The Abitibi Belt has supplied $Eq91.3 billion of the $Eq102.6 billion of metals mined from Archean rocks, of which $Eq33.17 billion has been contributed by the giant Kidd Creek deposit. The Appalachian Orogen has been the second most productive metallogenetic province in Canada, but here again it is a single giant deposit, the Brunswick No. 12, that has contributed $Eq26.7 billion of a total $Eq46.8 billion. The Proterozoic deposits of Manitoba and Saskatchewan at $Eq29.9 billion rank third (Fig. 21), of which $Eq12.9 billion was contributed by the Flin Flon deposit. The geological age distribution for reserves follows the same pattern as for production (Fig. 21) but measured, indicated, and inferred resources are dominated by the $Eq15.4 billion contained in the Mesozoic Windy Craggy deposit of British Columbia and the $Eq12.6 billion of measured and indicated resources of the Archean Slave Province (Fig. 20).

Economic Context and Statistics

Volcanogenic massive sulphide deposits have been a mainstay of the Canadian metalliferous mining industry, the $Eq192.4 billion of metals that have been mined being second only to magmatic Ni-Cu deposits for a single deposit type (Fig. 5). As a proportion of Canada's total non-ferrous metal and diamond wealth, VMS deposits account for 23% of production, 11% ($Eq20.1 billion) of reserves, 17% ($Eq78.7 billion) of measured and indicated resources, and 4% ($Eq4.0) of inferred resources (Table 3). Volcanogenic massive sulphide deposits have been the source for 68% of Canada's Zn, 52% of its Ag, 40% of its Cu, 32% of its Pb, and 13% of its Au production (Fig. 4A), and currently produces virtually all of its Zn, Pb, and Ag, and 22% of its Cu (Fig. 4B). On average, 46.0% of their value has been contributed by Zn, 31.5% by Cu, 10.8% by Au, 8.1% by Ag, and 3.6% by Pb, but the relative proportion of the different metals within individual deposits varies widely and the amount of metal contained in different deposits varies over four orders of magnitude (Fig. 22). Some VMS deposits are so rich in Au that it is the main economic commodity (Fig. 22) and have been classified as a separate mineral deposit type (Dubé et al., 2007), although some deposits may have been enriched in Au by the superimposition of epigenetic Au-rich mineralization (Mercier-Langevin et al., 2007).

An alarming statistic is that reserves at $Eq20.1.0 billion (Fig. 6) are sufficient only for four more years of mining at the 2005 rate, and all currently producing VMS deposits will be mined out in less than a decade (with the possible exception of the 777/Callinan mine near the Saskatchewan-Manitoba border). Thus, production from this deposit type will continue to rapidly decline unless some of its $Eq78 billion in measured and indicated resources (Fig. 7) are converted into reserves by the opening of new mines. Outside of the Windy Craggy deposit, which is not likely to be mined in the near future because of environmental issues, the largest resources are in the Hackett River-Izok Lake areas of Northwest Territories, which are also unlikely to be mined until a surface transportation infrastructure is established, such as the proposed Bathurst Inlet port and road project (e.g. Nunavut Impact Review Board, ftp.nunavut.ca/nirb/nirb_reviews/current_ reviews/03UN114-BIPAR_PROJECT/02-REVIEW, last accessed March 2007). The relatively recent discovery of the McFauld Lake and Coulon deposits (Fig. 20) demonstrates the potential of the Superior Province to the north of the Abitibi Belt. Furthermore, the relatively recent discovery of the Ansil West deposit in the Noranda camp and the Bracemac deposit in the Matagami camp demonstrates that additional deposits may still be found in established mining areas.

The main attraction in exploring for VMS deposits is the reasonably high value of their ores (Figs. 5, 23) and the high level of understanding, compared to other deposit types, of geological, geochemical, and geophysical vectors to their ores. Their polymetallic composition provides the added economic benefit of being a buffer against fluctuations in prices for any one metal. The weighted average metal content per tonne of ore is $Eq174/t for production (Fig. 9), $Eq185/t for reserves (Fig. 10), $Eq96/t for measured and indicated resources (Fig. 11), and $Eq186 for inferred resources (Fig. 12). The average value per tonne for production is at the low end of the range of ores mined during the past five years (Fig. 23A), which suggests that most deposits mined in the past with ore values of less than $Eq150/t may not be economically mineable today (except those mined by open pit). Deposits with metal contents per tonne of more than $Eq400/t include deposits unusually rich in precious metals (e.g. Eskay Creek and Homestake) and those poor in Fe sulphides (deposits of the Buchans district). Values of the metal contents for reserves (Fig. 23B) are generally lower than those for production (Fig. 23A), a reflection of most VMS producing mines coming to the end of their mining lives when lower grade ores are last to be mined. The bulk of VMS measured and indicated resources have metal contents less than $Eq150/t (Fig. 23C) and, like low-value past producers, may also not be candidates for mining under modern economic conditions.

Lode Gold Deposits

Geological Characteristics and Distribution

A lode gold deposit is a hydrothermal deposit whose principal commodity is Au. Sixteen subtypes of lode gold deposits (Poulsen et al., 2000) can be distinguished among three main groups:

1. Those formed at depths of 5 to 10 km, and variably termed orogenic, mesothermal, shear zone-related, or greenstone-related quartz-carbonate vein deposits; these deposits consist of structurally controlled quartz-carbonate veins and typically occur in greenschist-facies metamorphic rocks of orogenic belts (Robert, 1996; Dubé and Gosselin, 2007). The majority of deposits are adjacent to major, deep-seated reverse-oblique faults, particularly dilational zones (Hodgson, 1989) and were probably originally related to collision, obduction, and/or transtensional tectonics, but have a complex and long-lived structural history (Goldfarb et al., 2005). The mineralization generally took place during the later stages of orogenic crustal shortening, post-dating peak metamorphism of the host rocks. The mineralization is generally coeval with felsic to intermediate intrusions of the lode Au district and it is debated whether the genesis of the Au deposits is related to these intrusions or whether both are different expressions of the same deep crustal thermal event (Goldfarb et al., 2005). The Au deposits are associated with large-scale carbonate alteration, particularly along major faults, throughout the district (Dubé and Gosselin, 2007). This group of lode Au deposits accounts for 83.5% of Canada's total lode Au resources.
2. Intrusion-related deposits formed at 1 to 5 km depth, generally in the same way as porphyry deposits, and include the same range of mineral deposit styles, such as sulphide-rich veins, breccia pipes, skarns, etc. (Poulsen et al., 2000). Almost half the Canadian deposits of this type occur in Archean rocks (Appendix 1, DVD) with most of the remainder occurring in Mesozoic rocks of the Cordillera. It should be noted that this definition of ‘intrusive-related Au deposits', also used by Dubé and Gosselin (2007, Appendix 1, DVD) is not the same as that used by Goldfarb et al. (2005) and Groves et al. (2005) who restrict the term to generally low-grade deposits associated with reduced granitoids that occur on the foreland side of Phanerozoic continental arcs. Intrusion-related lode Au deposits accounts for 14.6% of Canada's total lode Au resources.
3. Epithermal deposits formed at less than 1 km depth and typically consist of quartz-bearing veins or low-grade precious metal disseminations formed from acid (quartz-alunite-kaolinite subtype) or neutral-alkaline (quartz-carbonate-adularia subtype) hydrothermal fluids generated by the devolatilization of felsic magmas and mixing of the magmatic fluids with meteoric waters in subaerial or shallow-water environments associated with calc-alkaline to alkaline volcanos of continental arcs and back arcs (Taylor, 1996; Simmons et al., 2005). Most preserved epithermal deposits in Canada are Mesozoic or younger in age and occur in the Cordillera because the shallow parts of continental arcs are not commonly preserved in older orogens. Epithermal lode gold deposits account for 2.8% of Canada's total lode gold resources.

Gold-rich VMS deposits (Dubé et al., 2007) and Au-rich porphyry deposits in lode gold deposits, are here included with VMS deposits and porphyry deposits, respectively

Most orogenic lode gold deposits in the world were formed during the intervals 2800 to 2550 Ma, 2100 to 1800 Ma, and 600 to 50 Ma, and most epithermal deposits that have been preserved were formed during the less than 50 Ma period (Goldfarb et al., 2005). Canadian lode gold deposits have a similar chronological distribution, which corresponds to the major periods of continental accretion (Fig. 16). The most productive lode hold districts in Canada are of the orogenic lode gold type, led by the Timmins, Kirkland Lake, and Val d'Or-Noranda mining centres in the Abitibi Belt in Ontario and Quebec (Fig. 24). Although age dating of deposits is sparse, most seem to have formed in the interval 2740 to 2620 Ma, up to 100 Ma later than their host rocks (Dubé and Gosselin, 2007). Like the age of their host rocks, they show a general decrease in age from north to south (Percival, 2007). The largest unmined orogenic Au resources are in the Tundra deposit of the Mackenzie district, the Meadowbank and the Hope Bay deposits, occurring in the Archean Slave Province of Nunavut (Fig. 24). The major Proterozoic orogenic lode gold deposits are in the Lynn Lake and Flin Flon areas of Manitoba and adjacent areas in Saskatchewan, though with a total resource metal content of about $Eq4.5 billion, are small compared to the $Eq143.6 billion content in Archean deposits. Similarly, Phanerozoic orogenic lode gold deposits of the Appalachians ($Eq2.0 billion) in the east and the Cordillera ($Eq5.3 billion) in the west, are similarly small in comparison. The largest intrusion- related deposits are those of the Hemlo district in western Ontario with a total resource of $Eq11.0 billion (Fig. 24).

Economic Context and Statistics

Orogenic lode gold deposits have supplied 80% of Canada's historic lode Au production (Fig. 4A) and in 2004 contributed 77% of the Au produced in Canada, which in turn accounted for 10% of Canada's total non-fuel mineral production (Fig. 1). With over 280 deposits that have been mined in Canada, lode Au deposits have not only been a major employer in the mining industry but the economic base for the establishment of northern communities, such as Timmins in Ontario and Val d'Or in Quebec. Supporting 27 different mining operations during 2003 to 2005,which is more than any other deposit type, and attracting 49.5% if the $1.1 billion invested in mineral exploration during 2005 (Natural Resources Canada, 2006), lode gold deposits continue to underpin a major part of the socio-economic infra structure of the Canadian mining and exploration industries. The development of lode gold deposits has often been the vanguard in the opening of new districts to the exploration for other mineral deposit types, so the planned opening of Meadowbank deposits in Nunavut may very well be the harbinger of increased economic prosperity to that territory.

Canada's total production from lode gold deposits to the end of 2005 is $Eq131.62 billion, representing 15.6% of total non-ferrous production. Lode gold is the third most economically productive deposit type after magmatic Ni-Cu and VMS deposits (Fig. 5, Table 3). On average, almost 95% of the contained Au is recovered (Fig. 3), this high recovery rate compared to base metals recovery rates (Fig. 3) being due to the chemical leaching methods for Au compared to the mechanical differential flotation methods for metal sulphide ore minerals. Nearly all the value (98%) of production from lode gold deposits (Fig. 5) comes from the Au content, but this proportion may be somewhat overstated because Auproducing mining companies usually do not report the amount of byproduct metals, such as Ag or Cu, unless they make a substantial contribution to total revenues. The total amount of Au produced (Table 2) is also understated because it does not include all small mines, especially those of the 19th and early part of the 20th century for which records are sparse. The metal content of reserves in lode gold deposits at $Eq9.63 billion is the lowest of all deposit types currently being mined (Fig. 6) and represents only 5.3% of Canada's total non-ferrous metal and diamond reserves. More lode gold deposits have been re-evaluated than other deposit types since the introduction of the NI 43-101 reporting standard. This has had the effect of reclassifying a higher proportion of historical ‘reserve' estimates for lode gold deposits as inferred resources in comparison to the arbitrary reassignment of most historical reserves for other deposit types to measured and indicated resources in Appendix 1 (DVD). It also explains why the $Eq27.9 billion for lode gold (Table 3) represents only 6.1% of Canada's total nonferrous metal and diamond measured and indicated resources but the $Eq19.49 billion for lode gold (Table 3) is a much higher 20.2% of Canada's total non-ferrous metal and diamond inferred resources.

The weighted average metal content per tonne of ore is $Eq132/t for production, $Eq69.4/t for reserves, $Eq48.8/t for measured and indicated resources, and $Eq70.1 for inferred resources (Figs. 5, 6, 7, and 8, respectively). These are the lowest dollar equivalent of metal contents of all mineral deposit types exploited by underground mining. The relatively low ore values are economic to mine because recovery rates of Au from lode gold deposits average 93.4%, which is much higher than the recovery rates for base metals (Fig. 3), and the beneficiation process produces Au bars at the mine site, which avoids both the transportation costs of bulky base metal sulphide concentrates and smelting charges. In contrast to other deposit types, dollar equivalent per tonne values for reserves (Fig. 10) and resources categories (Figs. 11, 12) are very low compared to production values (Fig. 9). This is because the tonnage of the reserves and resources categories are dominated by those reported for the Porcupine joint venture, aimed at open-pit mining of remaining low-grade (1.2-2.6 g/t Au) resources in the Timmins area, particularly around the Dome mine (Appendix 1, DVD). Though low for lode gold deposits in general, the $ $Eq29/t to $Eq65/t of these open-pit lode gold ores is high compared to the open pit ores of porphyry mineral deposits (Figs. 9, 10, 11, 12).

As with other deposit types, there is a large range in the dollar equivalent of metal content in the mineral resource categories for different deposits ranging from about $Eq20/t to over $Eq450/t (Fig. 25). Most deposits fall in the $Eq50/t to $Eq150/t range (Fig. 25A,C). Deposits mined during the 2002 to 2005 period have much the same range of dollar equivalent per tonne of metal grades as those mined prior to 2005 (Fig. 25A), indicating that there has not been a major shift in mineral deposit economics over the past 50 years, presumably because higher labour costs have been offset by more efficient mining techniques.

Porphyry Deposits

Geological Context and Distribution

Porphyry deposits are large, low-grade Cu, Mo, Au, Ag, W, and/or Sn magmatic-hydrothermal deposits spatially associated with felsic to intermediate porphyritic intrusions within 1 to 6 km of the paleosurface that formed in continental- and island-arc geological settings (Kirkham, 1972; Kirkham and Sinclair, 1995; Seedorf et al., 2005; Sinclair, 2007). The deposits typically contain hundreds of millions of tonnes of ore but the grades are generally <1% Cu and <0.1% Mo so that they can only be economically mined by open pit methods. Porphyry Cu deposits generally occur above magma cupolas in the root zones of subaerial andesitic to dacitic stratovolcanoes (Seedorf et al., 2005). Porphyry Mo deposits are typically associated with A-type granites of back-arc continental extensional geological environments, and porphyry Au deposits have an affinity with alkaline intrusions (Sinclair, 2007).

The volume of rocks mineralized by ore-bearing veins and replacements is up to 4 km3, with the deposit generally zoned from a barren core, through an interior shell of veins rich in metal sulphides, to upper and outer zones containing Pb-, Zn-, Ag-, and/or Au-rich skarns, mantos, and epithermal veins (Einaudi, 1982; Jones, 1992; Kirkham and Sinclair, 1995; Seedorf et al., 2005; Sinclair, 2007). The shallow part of the porphyry system may be capped by a zone of siliceous quartz-alunite-pyrite alteration formed by ultra-acidic hot spring and fumarolic activity.

The great bulk of Canadian porphyry mineral resources are in British Columbia (Fig. 26), which accounts for about 85% of production and 87% of total porphyry mineral resources. This is because they are most abundantly preserved in the younger orogens where the depth of erosion has not reached the lower depth limits of porphyry formation. Yukon accounts for only 0.5% of production and 5% of total resources. Outside of the Cordillera, porphyry deposits occur in the Archean of the Superior Province and in the Appalachian Orogen (Fig. 26). Of these, the Appalachian Gaspé copper and the Archean Troilus deposits in Quebec, have been the most important producers with production estimated as $Eq11.8 billion and $Eq2.4billion, respectively (Fig. 26).

Economic Context and Statistics

Porphyry deposits provide about 60% of the world's primary Cu and virtually all the world's Mo and Re, as well as significant proportions of primary Au, Ag, and Sn (Sinclair, 2007). Most of this production comes from circum-Pacific Mesozoic to Cenozoic orogenic belts as well as scattered deposits from the Mesozoic Alpine-Tethyan Orogen of Europe and Asia, and other orogens as old as Archean. Increasing interest and exploration efforts are being directed towards central Asia following the discovery during 1998 to 2003 of the 2.5 billion tonne Oyu Tolgoi deposit in the Paleozoic Tuva Mongol arc, Mongolia (Perelló et al., 2001).

The main economic attraction of porphyry deposits is their very large tonnages that provide the long mine life preferred for corporate planning and stability purposes. However, the capital investment required for the development of such large-scale operations is correspondingly large. For example, estimates for preproduction development costs are over $1.1 billion for the Galore Creek deposit in British Columbia (NovaGold Resources Inc., 2006) and over $1.4 billion for the Oyu Tolgoi deposit in Mongolia (Ivanhoe Mines Ltd., 2006). An important factor for the development of porphyry deposits is the presence of a higher grade (2-4% Cu) supergene zone of secondary Cu enrichment, which allows the accelerated repayment of the large preproduction investment. Mitigating against the development of porphyry deposits, is the social factor of a widespread public perception of the negative environmental impacts of open-pit mining, and this has prompted some major mining companies to research methods of bulk underground mining methods that could compete with the low mining costs of the open-pit method (Morgan, 2005)

The value of metals mined from Canadian porphyry deposits is about $Eq48.5billion with about 70% of this value being attributable to Cu, 14% to Mo, 13% to Au, and 2.5% to Ag. In 2005, porphyry deposits accounted for 100% of the Mo, 50% of the Cu, and 9% of the Au produced in Canada (Fig. 4B). Other metals, particularly W, Sn, and In from the East Kemptville and Mount Pleasant deposits, have contributed <1% of total production value. The contribution of Re, currently worth about $1200/kg and recovered from Mo concentrates, is not reported. On average, 83.4% of the Cu, 68% of the Au, and 51% of the Mo are recovered, so overall 75% of the metal value of porphyry ores is converted into economic wealth. The majority of Canadian porphyry resources contain less than $Eq20/t (Fig. 27), which is less than 10% the value of ores for other base metal mineral deposit types, and so is dependent on the economies of largescale mining to be economically viable.

Porphyry reserves contain about $Eq15.6 billion in metal value (Fig. 6), the main contrast to past production (Fig. 5) being the larger proportion (21%) contributed by Au. Measured and indicated resources (Fig. 7) are estimated to contain about $Eq185.3 billion of metal based mainly on historical estimates, the great bulk of which are in British Columbia (Fig. 26), which represents 40% of Canada's total in this resource category.

Sedimentary Exhalative Deposits

Geological Contexts and Distribution

SEDEX deposits are stratiform to stratabound layers or lenses of Fe, Zn, and Pb sulphides, usually with a significant Ag content, that occur in sedimentary basins and were formed by the submarine venting of hydrothermal fluids (Goodfellow and Lydon, 2007). The sequence of sedimentary rocks that hosts the deposits are typically the sag phase of an intra- or epicontinental rift though some deposits (e.g. Sullivan, British Columbia) occur in the rift-fill part of the sequence. The question as to whether the lithospheric extension causing the rifting is related to mantle plume-head spreading or far-field back-arc extension has not as yet been addressed. Sedimentary exhalative deposits are typically much larger than VMS deposits and those that have been mined generally contain about 50 to more than 100 Mt of ore (Goodfellow and Lydon, 2007).

Most of Canada’s SEDEX deposits are in British Columbia and Yukon (Fig. 28), where they occur in the Mesoproterozoic Belt-Purcell basin (Lydon, 2007) and in basinal facies of the Paleozoic miogeocline, notably the Selwyn Basin (Goodfellow, 2007b). A number of small Zn- Pb deposits in Cambrian carbonate rocks of the Kootenay arc and eastern Shuswap metamorphic complex in southern British Columbia may be of the SEDEX type. However, the high degree of deformation in these areas, which has transposed both compositional layering and sulphide mineralization into the foliation, leaves doubt as to whether these carbonate- hosted deposits are Irish-type SEDEX deposits or Mississippi Valley type. The same enigma applies to Zn-Pb occurrences in marble-rich sequences of Mesoproterozoic- Neoproterozoic supracrustal sedimentary basins of the Grenville Province in Ontario and Quebec (Corriveau et al., 2007), which have geological and metallogenetic affinities to the large Zn-Pb deposits of the Balmat-Edwards area of northern New York State. In the eastern part of Canada, the Walton deposit and MVT deposits (Paradis et al., 2007) of the Mississippian Windsor Basin may represent the transatlantic equivalent of the highly productive Irish ore-forming environment that produced deposits with both seafloor (SEDEX) and epigenetic (MVT) characteristics.

Economic Context and Statistics

Sedimentary exhalative deposits are an important source for Zn, Pb, and Ag. Judging from global production statistics for Zn (Jorgenson, 2004) and Pb (Smith, 2003), and with the caveat of the uncertainty of the mineral deposit types from which China obtains its world-leading 23.5% supply of primary Zn and 22.4% of primary Pb supply, it is estimated that SEDEX deposits provide more than 30% of the world’s Zn and more than 40% of the world’s Pb primary metal supply. The Mt. Isa, George Fisher, Cannington, McArthur River, and Broken Hill mines of Australia and the Red Dog mine of Alaska are the current major SEDEX producers. The main economic attractions of SEDEX deposits are the potential for very large tonnages of ore and that a high proportion of deposits of this type are strongly zoned with a high-grade core passing laterally into lower grade mineralization. Mining of these high-grade ores early in the mining operation allows for a shorter pay-back period.

The major production in Canada from SEDEX deposits came from the Sullivan deposit in British Columbia, which closed in 2001, and the Anvil Range deposits of Yukon, which last produced in 1996. Total production from SEDEX deposits has totaled $Eq41 billion (Fig. 5), and supplied 19% of the Zn, 54% of the Pb, and 13% of the Ag (Fig. 4A) produced in Canada to the end of 2005. There are $Eq32.5 billion Zn, Pb, and Ag in measured and indicated resources (Fig. 7) and $Eg13.4 billion in inferred resources (Fig. 8) of this deposit type, mainly in Yukon and British Columbia, notably the deposits of the Howards Pass, MacMillan Pass, and the Gataga districts (Fig. 28). The $Eq157.9/t metal content of measured and indicated resources is only slightly lower than the $Eq171.1/t content of ores that have been mined (Fig. 29), suggesting that at least part of these resources are marginal to being economically mineable, if a suitable surface transportation and power infrastructure were in place. The value of the average Canadian SEDEX mineral resource ($Eq155/t) is higher than the value of the average global SEDEX mineral resource ($Eq135/t), which gives Canadian deposits a competitive edge in attracting development investment when the high-grade deposits currently being mined in other countries become exhausted. Recent exploration drilling in the Howards Pass district has shown that mineralization occurs in the area between the XY and Anniv deposits, which will likely lead to an increase in the amount of mineral resources currently estimated for the district.

The $Eq171/t average value for Canadian production from SEDEX deposits is about 30% less than the global production average value (Fig. 29). One reason for this is that mining of large foreign deposits has largely been restricted to the higher grade cores that do not include the lower grade surrounding zone(s). For example, the approximately 124 Mt of production from the Mt. Isa mine has an average grade of 6.7% Zn, 6.3% Pb, and 150 g/t Ag (Perkins, 1990), or about $Eq223/t, but the average grade of the 367 Mt of the remaining mineral resources (that is potentially mineable at the Black Star and Mount Isa open pits) is about 4.2 % Zn, 3.2% Pb, and 68 g/t Ag (Xstrata Report, 2006), or about $Eq125/t. Another reason is that the global production average includes deposits with large tonnages of exceptionally high-grade ore, such as the 150 Mt of $Eq256/t that has been mined at Broken Hill, Australia (Mackenzie and Davies, 1990) and the 72 Mt of $Eq327/t being mined at Red Dog, Alaska (TeckCominco Annual Report for 2005). Examples of large deposits with exceptionally high grades have not yet been found in Canada.

Mississippi Valley-Type Deposits

Geological Context and Distribution

Mississippi Valley-type (MVT) deposits are irregular stratabound to discordant epigenetic replacements and/or open-space fillings of carbonate sedimentary rocks by Zn and Pb sulphides (Leach et al., 2005; Paradis et al., 2007). Individual bodies are generally scattered over a district that may be hundreds of square kilometres in area and contain tens to hundreds of individual deposits (Leach et al., 2005) and range from a few hundred thousand of tonnes to tens of million of tonnes (Paradis et al., 2007). Mississippi Valleytype deposits tend to occur in platformal carbonate sequences situated in the foreland regions of orogens, a geotectonic setting thought to reflect the zone of tectonically induced migration of metalliferous brines from basins of the continental margin into carbonate aquifers of the platformal sequences (e.g. Garven, 1985; Leach et al., 2001, 2005; Paradis et al., 2007). Most MVT deposits in Canada (Fig. 30) are foreland to the Cordilleran Orogen of Yukon and Northwest Territories where they occur in Neoproterozoic to Devonian carbonates. Those of the Maritimes occur in Ordovician to Mississippian carbonates adjacent to the Appalachian Orogen. Polaris, in Ordovician carbonates, is related to the Paleozoic Ellesmerian tectonism (Symons and Sangster, 1992) as may Nanisivik in Neoproterozoic carbonates, though there is debate that it may be related to Grenville-age compressional tectonics (Dewing et al., 2007). The Gays River mineralization was formed by the ca. 297 Ma (Kontak et al., 1994) Pennsylvanian-Permian migration of basinal brines, presumably under the influence of Alleghanian tectonism.

Economic Context and Statistics

The mining of MVT deposits was especially important to Canada during the 1980s when production from the deposits at Pine Point in Northwest Territories, Polaris on Little Cornwallis Island, Nanisivik on Baffin Island, and Newfoundland Zinc (Daniel’s Harbour) in western Newfoundland, contributed about 27% of the Zn and 15% of the Pb to Canada’s primary production of these metals. This production declined to 20% of the Zn and 8% of the Pb during the 1990s until the closure of the Polaris and Nanisivik mines in 2002, when all production in Canada from this deposit type came to an end. Although the value of the metal content of the ores are comparable to that of both the VMS and the SEDEX deposit types (Fig. 9), MVT ores tend to be coarser grained and the carbonate host rocks relatively soft, both of which decrease beneficiation costs. The carbonate host rocks, while advantageous in averting acid mine drainage, tend to be highly productive aquifers increasing water-control costs, which can be a major factor, as at the Pine Point and Newfoundland Zinc deposits.

Canadian production from MVT has totaled about $Eq19.0 billion, 95% of it coming from just three mines: Pine Point at $Eq9.1 billion, Polaris at $Eq5.6 billion, and Nanisivik at $Eq3.2 billion. The average value of MVT ores that have been mined is $Eq173.8/t, about the same for other deposit types mined for Cu, Zn, and/or Pb by underground methods (Fig. 9), but ranges from $Eq81/t for the 741,000 tonnes of ore mined at Gays River to $Eq278/t for the ores from Pine Point. For all deposits, most of this value is attributable to the Zn content and the remainder mainly to Pb (Fig. 5). In contrast to other deposit types from which galena is mined (VMS, SEDEX, and some vein types), MVT deposits on average do not seem to have a significant Ag content. The low Ag value in ores for MVT deposits (Fig. 9) is because Ag grades for production are reported for only two of the fourteen deposits contributing to these statistics. Similarly, the compilation of Leach et al. (2005) reports Ag grades for only 22 of 88 deposits with reported Zn and Pb grades.

Mississippi Valley-type measured and indicated resources are estimated at $Eq10.7 billion (Fig. 7), and like past production, most of this value is from the Zn content. Measured and indicated resources have an average value of $Eq117/t (Fig. 11) and is much lower than for other base metal deposits mined by underground methods because about 40% of the resources are contributed by the low-grade ($Eq88/t) deposits of the Gayna River district of Northwest Territories (Fig. 30). The highest grade measured and indicated resources are in the Prairie Creek deposit ($Eq353/t), which has unusually high Ag and Cu contents. The Prairie Creek deposit, with its estimated minimum total $Eq4.5 billion of measured, indicated, and inferred resources (Fig. 30) has already undergone most of its preproduction development, but actual production is awaiting resolution of land-use issues. Ground water management is likely to be a major negative factor for development of the $Eq2 billion of measured and indicated resources remaining in the Pine Point district (Fig. 30) that are largely on the Great Slave Reef property (Hannigan, 2007), and the low grades and remote location are likewise negative factors for the development of the Gayna River resources.

Uranium Deposits

Geological Context and Distribution

Most of Canada’s U resources are related to the global phenomenon of U concentration during the Proterozoic, starting with the U paleoplacers of Elliot Lake at the beginning of the Paleoproterozoic and culminating in the hydrodynamic events during the Mesoproterozoic that formed the epigenetic deposits of the Athabasca sedimentary basins. Other types of U deposits include veins, pegmatites, and sandstone-hosted deposits.

Unconformity-related uranium deposits: The unconformity- related deposits of the Athabasca Basin (Jefferson et al., 2007) (Fig. 31) contain more than ten times the amount mined from other deposit types and currently contribute all of Canada’s substantial uranium production. The deposits tend to be small (0.1 to 5.0 Mt), but with grades ranging up to 20% U contain very valuable ores (Figs. 9, 10). The ores are thought to have been formed during the exchange of groundwaters between the hydrochemical environment of basement rocks and the different hydrochemical environment of the overlying Athabasca Group sedimentary rocks, with U deposition taking place close to the unconformity surface presumable due to redox reactions. There is strong evidence of a spatial relationship between U deposits and graphite-bearing lithological units in the basement (Jefferson et al., 2007). Polymetallic deposits contain significant Ni, Co, Cu, Pb, Zn, Mo, and in some cases Au, Ag, and PGE in addition to U. These polymetallic deposits typically occur in basal sandstones and conglomerates of the Athabasca Group where the unconformity surface has been displaced by local faults and where groundwater from the Paleoproterozoic basement flowed upwards into the Athabasca Group (Jefferson et al., 2007). Monometallic deposits, containing only U in significant concentrations, typically occur along fracture, shear, or breccia zones for up to 400 m into the basement below the unconformity and are thought to have formed by the ingress of formational waters of the Athabasca Group downward into the basement (Jefferson et al., 2007). Sedimentation in the Athabasca Basin began at 1730 to 1750 Ma and continued to at least 1650 Ma. Formation of the U deposits occurred during one or both of two major hydrothermal events at about 1500 and 1350 Ma (Fig. 17) with remobilization events at 1176, 900, and 300 Ma (Jefferson et al., 2007). Other examples of unconformityrelated uranium deposits are known at the base of the Thelon Basin in Nunavut (Fig. 31).

Paleoplacer uranium deposits: Pyritic quartz pebble conglomerates in the Matinenda Formation near the base of the Proterozoic Huronian Supergroup are host to the paleoplacer uraninite deposits mined in the Elliot Lake district (Roscoe, 1996) during the period of 1957 to 1992. The age of the Huronian paleoplacers (Fig. 17) of the Elliot Lake district are approximately that of the felsic volcanic rocks of the Coppercliff Formation near the base of the Huronian Supergroup, which have been dated at 2450 Ma (Roscoe, 1996).

Other uranium deposits: The veins of the Beaverlodge district (Fig. 31) are mostly hosted by the Paleoproterozoic Tazin Group and are close to the contact with the overlying Mesoproterozoic Martin Formation of the Athabasca Group. The ore mineralogy of the veins in the Beaverlodge district (Fig. 31) is generally monometallic, consisting of pitchblende and lesser brannerite with carbonate gangue (Ruzicka, 1996). Classified by Ruzicka (1996) as “veins in shear zones” they may be exhumed representatives of the monometallic basement vein variety of unconformity-associated uranium deposits (Mazimhaka and Hendry, 1989; Jefferson et al., 2007). Similarly, the veins of the Eldorado area (Fig. 31), hosted by 1860 to 1875 Ma volcanic rocks of the Great Bear magmatic zone but with a mineralization occurring over the interval 1775 to 1665Ma with Pb isotope resetting at 1500 and 1420 Ma (Ruzicka and Thorpe, 1996b), may represent exhumed veins that formed below the unconformity at the base of the Hornby Bay Basin. The disseminated pitchblende, breccia fillings, and veins of the Makkovic area (Fig. 31) are hosted by aerially extensive flows, tuffs, and volcaniclastic sequences formed during the 1700 to 1900 Ma Makkovikian Orogeny (Gandhi and Bell, 1996). The mineralization occurs in felsic volcanic rocks that dominate the bimodal upper part of the 1805 to 1860 Ma Aillik Group. Isotopic ages of the deposits are between 1750 and 1800 Ma (Ghandi and Bell, 1996).

Pegmatite-associated and disseminated uraninite and uranothorite in Grenvillian rocks of the Bancroft area, Ontario, are associated with granitic to syenitic pegmatites but also occur in siliceous sulphidic marbles and calc-silicate skarns (Carter and Colvine, 1985). Low-grade uranium phosphate mineralization occurs in Miocene and surficial sediments near Kelowna, British Columbia, and in sandstones of the Proterozoic Hornby Basin in Nunavut.

Economic Context and Statistics

Most of Canada’s uranium production prior to 1984 came from the low-grade paleoplacer ores of the Elliot Lake district in Ontario, with a smaller amount produced from veins of the Beaverlodge district of Saskatchewan. Over their total production history, these deposits produced $Eq10.8 billion, almost totally as uranium (Fig. 5). However, the average $Eq59.5/t of these ores (Fig. 9) could not compete on the opened market with the much higher grade $Eq539.3/t grades of the unconformity-related deposits of the Athabasca Basin of Saskatchewan, resulting in the closure of the Elliot Lake mines in 1996 (Leadbeater, 1998) after producing about 144,000 t of U ($Eq7.7 billion) in 160 Mt of ore at a grade of about 0.9%U. Production of U from fault-associated veins of the Beaverlodge area amounted to about $Eq3.2 billion (Fig. 31) and about 6000 t of uranium ($Eq0.5 billion) was recovered at the Eldorado Ag-rich polymetallic veins (Ruzicka and Thorpe, 1996b). The amount of ore mined from individual mineral deposits of the Athabasca Basin is generally small, so that their overall contribution to the value of national mineral resource inventory is also relatively small, contributing only 3% of Canada’s total non-fuel mineral production in 2004 (Fig. 1) and only 1.27% of total historic non-ferrous metal and diamond production (Table 3), but obviously will far exceed the combined production from other areas when currently known reserves and resources have been mined. The $Eq14.6 billion of reserves in the Athabasca Basin deposits constitute 8% of Canada’s nonferrous metal and diamond reserves (Table 3). Unlike other deposit types, most of the unmined mineral resources of the Athabasca Basin are classified as reserves, leaving only $Eq2.6 billion as measured and indicated resources, which constitute only 0.6% of Canada’s mineral resources in this category. Known reserves and resources in the Athabasca Basin are sufficient for another 25 years of mining (Saskatchewan Interactive, 2006). Uranium in paleoplacers, veins, and pegmatites is generally considered to be of too low a grade or too low a tonnage to economically compete with the unconformity-associated type of U deposit. However, this outlook may change if the price of U continues its upward trend of the past two years.

Uranium has a much higher value than other non-precious metals (Table 1), which accounts for the unconformityrelated ores of the Athabasca Basin having the highest weighted average value per tonne of all mineral deposit types at $Eq540/t for production (Fig. 9) and $Eq5190/t for reserves (Fig. 10). Due to the rapid rise in the price of U during 2004 and 2005 (and continuing through 2006), the dollar equivalent value for U ores would be more than double the figures given here if the current U price were used rather than its 10 year average price. As with other deposit types, there is a great deal of variation between deposits, ranging from a high of over $Eq10,000/t for production (and reserves) at the high-grade McArthur River deposit, down to about $Eq300/t at the Rabbit Lake and Cluff Lake deposits. The very high value per tonne for reserves of $Eq5190/t (Fig. 10) is because nearly half the tonnage of current reserves is in the very high-grade McArthur River and Cigar Lake deposits (Appendix 1, DVD). The relatively low value of $Eq293/t for measured and indicated resources of the Athabasca Basin U deposits (Fig. 11) is because the bulk of the resources are in the low-grade (0.12% U) deposits of the Hidden Bay area.

Outside of the Athabasca Basin, significant (>$Eq0.1 billion) U resources are restricted to the Kiggavik deposits of the Thelon Basin, deposits in the Makkovic area of Labrador, and deposits in Miocene sediments near Kelowna, British Columbia (Fig. 31). The Kiggavik Main deposit, with nearly 2.5 Mt of ore valued at $Eq264/t, seems to have better economic prospects than the 1.9 Mt Blizzard deposit in British Columbia, valued at $Eq112/t, or the 6.2 Mt Michelin deposit in Labrador, valued at $Eq54/t.

Miscellaneous Deposits

Geological Contexts and Distribution

Various mineral deposit types, which occur in Canada and are economically important elsewhere in the world, are either included in the seven deposit types outlined above nor, except for iron oxide copper-gold deposits (IOCG; Corriveau, 2007), described or compiled elsewhere in this volume. They are grouped here as veins, IOCG, skarns, and diagenetic copper.

Veins are infillings of fractures by ore minerals, and although veins form at least part of the mineralization of various deposit types, particularly lode gold and porphyry deposits, some are wide enough and rich enough to have been mined for metals other than Au. The economically most important of these vein deposits are Ag-rich and represented in Canada by the Ag-Co-Sb veins of the Cobalt area of Ontario, the Ag-Pb-Zn veins of the Elsa (Keno Hill) area of Yukon, and the Ag-U veins of the eastern Great Slave Lake area, Northwest Territories. The Ag veins of the Cobalt area (Fig. 32) generally occur within a few hundred metres of the Nipissing diabase sills and the unconformity between the Huronian Supergroup and metavolcanics of the Archean basement (Marshall and Watkinson, 2000). U-Pb ages of baddelyite from the Nipissing diabase and vein-related rutile have similar ages of 2219 and 2217 Ma, respectively (Andrews et al., 1986), and led Marshall and Watkinson (2000) to suggest that the two events are genetically related. Most deposits of the Elsa area occur in Mississippian Keno Hill quartzite and are zoned with respect to the Mayo Lakes pluton. Sinclair et al. (1980) obtained a 90 Ma K-Ar age for the mineralized veins, which probably represents distal veins of intrusion-related lode Au systems of the Cretaceous Tintina Au province (Lynch, 1989; Lynch et al., 1990; Groves et al., 2003).

Iron oxide copper-gold deposits (Corriveau, 2007) are a relatively new mineral deposit type (Hitzman et al., 1992) inspired by the 1975 discovery of the immense Cu-Au-U-Ag- REE Olympic Dam deposit in the Gawler Craton of South Australia (Roberts and Hudson, 1983). The debate continues as to whether hematite/magnetite-rich deposits with Cu, Au, and other metal enrichments are a distinct genetic class or whether they are local variants of other deposit types, particularly porphyry deposits (Williams et al., 2005; Corriveau, 2007) formed by magmas or magmatic-hydrothermal systems interacting with pre-existing highly saline sulphate-rich groundwaters (e.g. Barton and Johnson, 2000). The only IOCG deposits in Canada with a measured resource are the Sue-Diane and NICO deposits of the 1850 to 1880 Ma Great Bear Magmatic Zone of the Northwest Territories (Fig. 32). The 1600 Ma Wernecke breccias in the Wernecke and Ogilvie mountains, Yukon, in places, are mineralized with hematite/magnetite and associated Cu-Co-Au-Ag-U enrichments (Thorkelson et al., 2001; Hunt et al., 2005)

Skarn deposits are characterized by Fe-enriched pervasive alteration of carbonate-rich rocks by magmatic hydrothermal fluids at the margins of felsic plutons that contain metals in economic concentrations. Although skarns are usually a part of the mineralization associated with porphyry Cu and Mo deposits, some skarn deposits seem to have been formed in the absence of porphyry-type mineralization. Of particular interest are the W-rich skarns (Dawson, 1996) associated with Cretaceous stocks of Yukon and Northwest Territories and the Cu-rich skarns of the Whitehorse copper belt, Yukon (Dawson and Kirkham, 1996).

Diagenetic copper deposits include the Kuperschiefertype, redbed copper and volcanic redbed copper deposit types of Kirkham (1996a,b). Although there has been no production from this type of deposit in Canada, elsewhere in the world they have been prolific producers, notably in the central African copper belt and in the Kuperschiefer of Poland. Deposits commonly contain >1 Mt of Cu. They are formed when oxidized fluids carrying soluble cupric compounds enter a reducing, H2S-rich environment and precipitate as Cu sulphides or in some cases as native Cu. They are usually thin but widespread sheets that mark the interface between oxidizing and reducing conditions during basinal dewatering stages of diagenesis. The two examples of diagenetic copper deposits, the Redstone deposit in Neoproterozoic sediments of the western Northwest Territories and the Zone (or Dot) 47 deposit in shear zones within the Coppermine basalts of Nunavut (Fig. 32), have not been mined, but remain potentially large but remote Cu resources.

Economic Context and Statistics

Veins: The mining of veins was ideally suited to the mining methods of the 19th and early 20th century, and therefore was important to Canada’s mining history. Mining of Agrich veins in the Cobalt area of Ontario (Fig. 32) produced $Eq4.7 billion and during its peak production in 1908 supported 34 different mines (Udd, 2000). Mining at Cobalt attracted the investments to develop a railroads transportation infrastructure northward from the Great Lakes – St. Lawrence corridor, which in turn provided the means for settlement in these areas and helped set the scene for the discovery of the mineral deposits of the prolific Abitibi belt to the north. The Keno Hill deposits of the Elsa area were discovered in 1906 in the wake of the Klondike Au rush and 16 deposits from the area were intermittently mined during the period of 1921 to 1988, producing ores with Ag, Pb, and Zn contents of about $Eq2.4 billion. The opening of the mines provided a much needed economic boost at a time when the population of Yukon had declined to 4,157 people in 1921 with the decline of Klondike placer Au mining. The Echo Bay and Camsell River area Ag-rich polymetallic (Ag-UCu- Co-Ni-Bi-Sb-Pb-Zn) veins at the east end of Great Bear Lake together produced metals with a value of about $Eq0.85 billion, with about half the metal value derived from Ag. However, the area has historical importance, not because of its Ag production but for its U production from the Eldorado mine. First opened in 1933 as a source of Ra, it closed in 1940 only to be re-opened in 1942 as a source of U for the Manhattan Project that led to the development of nuclear arms. Copper-Au veins are currently being mined in the Chibougamau district of Quebec.

Iron oxide copper-gold deposits: The NICO and Sue- Diane deposits together have a metal content of $Eq2.3 billion, which is a negligible proportion (0.15%) of Canada’s total non-ferrous metal and diamond resources. Most of the value in the $Eq1.8 billion NICO deposit lies in its Co content (74%), with the remainder contributed by Au (24%) and Bi (2%). At the $Eq0.6 billion Sue-Dianne deposit, most of the value is contributed by Cu (89%) and the remainder by Mo (8%) and Ag (3%).

Skarns: Although skarns are commonly a part of the mineralization styles included in porphyry deposits, the W-bearing skarns along the Yukon-Northwest Territories boundary (Fig. 2) are not part of recognized porphyry systems. They are economically and strategically important because they are the repository of the western world’s largest tungsten resource. Only the $Eq0.8 billion Cantung deposit, with a $Eq111.6/t resource, has been mined but the much larger $Eq4.8 billion Mactung deposit has not, perhaps mainly because of its lower grade $Eq60.2/t resource. The mining of small amounts of W in Canada was part of the war effort both during 1914 to 18 (Burnt Hill, Nova Scotia) and during 1939 to 1945 (Indian Path, Nova Scotia; Outpost Island, Northwest Territories; Emerald, British Columbia) (Udd, 2000). During the 1950s, the Emerald (Fig. 33), and nearby Dodger and Feeney skarn deposits were important sources of W in the free world (Udd, 2000). Canada’s position as a western world leader in W production seemed to have been consolidated by the discovery in 1954 and start of production in 1962 of the Cantung skarn deposit in Northwest Territories near the Yukon-Northwest Territories border (Fig. 32) and by the 1962 discovery of the large Mactung deposit and the 1984 start of W production from the Mount Pleasant porphyry deposit in New Brunswick (Fig. 26). Until 1986, Canada was producing about 8% of the world’s W supply, but in 1986 low-priced W exports from the People’s Republic of China forced the closure of Canadian W mines (Natural Resources Canada, 2004).

Diagenetic copper deposits are an important source of Cu in other parts of the world. In Canada, the Redstone deposit in the western part of Northwest Territories, with a $Eq5.1 billion resource, is Canada’s prime example, and there is a high potential for increasing the $Eq0.4 billion known resources of the Coppermine River area of Nunavut.

Kimberlite Diamond Deposits

Geological Context and Distribution

Kimberlite diamond deposits (Kjarsgaard, 2007) are diatremes and craters of kimberlite that contain diamond xenocrysts of sufficient grade and stone quality to be economic. The great majority of kimberlite pipes do not contain diamonds. Kimberlites (Skinner and Clement, 1979; Mitchell, 1986) are thought to have formed by the partial melting of carbonated garnet lherzolite in the asthenosphere at pressures of more than 5 GPa (~150 km depth). Kimberlites acquire their diamond content as their magmas rise through the subcontinental lithospheric mantle where diamonds may have previously formed in peridotite (mainly harzburgite) or eclogite of old lithospheric mantle under conditions of high pressure (>150 km depth) but relatively low temperature (<1200ºC) (Boyd et al., 1985). The formation of diamonds appears to have been episodic over Earth’s history, with major diamond-forming events occurring at 3.2 to 3.6 Ga, 2.7 to 2.9 Ga, 1.6 to 2.0 Ga, and 1.0 to 1.2 Ga (data in Gurney et. al., 2005), which broadly coincides with the time periods of major supercontinent assembly and generation of new continental crust (e.g. Kemp et al., 2006). Melting of the asthenosphere is thought to be triggered by tensile tectonic stresses and kimberlites reach the surface along upward propagating, fluid-filled fractures (Gurney et al., 2005). Lamproites, which may contain diamonds but are only of minor economic importance, are generated by partial melting of lithospheric mantle under conditions of greater hydrous content than kimberlites (Foley et al., 1987).

Diamond-bearing kimberlite (and lamproite) diatreme events also appear to have been episodic, occurring in the intervals 1140 to 1200 Ma, 456 to 542 Ma, 340 to 260 Ma, 147 to 173 Ma, 53 to 124 Ma, and 20 to 22 Ma (data in Gurney et. al., 2005). Most of these events are restricted to specific regions, whereas others occurred contemporaneously on different continents (Kjarsgaard, 2007).

The pressure-temperature stability field of diamonds mentioned above is met only in the environment of low geothermal gradients in the mantle root zones of thick old continental lithosphere of continental nuclei, giving rise to “Clifford’s Rule” that diamond deposits are found only in terranes older than 1.5 Ga (Clifford, 1966), particularly Archean cratons (Janse, 1984). Most of Canada’s diamond resources are in the Archean Slave Province of Northwest Territories and Nunavut (Fig. 33), with kimberlite eruptive events occurring during the Cambrian (Snap Lake at 523- 535 Ma; Gacho Kue at 542 Ma), the Jurassic (Jericho at 172 Ma), and Paleogene (Ekati at 53-56 Ma) (Kjarsgaard, 2007). The Archean Superior Province hosts the Victor kimberlite cluster of Ontario, probably of Jurassic age, and the Foxtrot (Renard), Quebec, of Neoproterozoic age (ca. 630 Ma) (Kjarsgaard, 2007). The Archean Sask Craton underlies the Fort à la Corne cluster of Upper Cretaceous age (95-105 Ma). Kimberlites have been found in the Arctic areas of the Archean/Paleoproterozoic Churchill Province and the Paleoproterozoic (1.8-2.4 Ga) of Alberta, as well as in probable Paleoproterozoic terranes of southeastern British Columbia and Nunavut (Kjarsgaard, 2007) but their diamond potential has yet to be determined.

Economic Context and Statistics

Although diamonds had been discovered in glacial drift south of the Great Lakes in the 19th century and in the Peterborough (prior to 1920) and Porcupine (1971) areas of Ontario, and the first in situ diamonds were questionably recovered from the Pain de Sucre kimberlite dyke just west of Montreal in 1967 by de Beers, it was the discovery of the Ekati diamond-bearing cluster of kimberlite pipes in the Lac de Gras area that started the largest staking rush in Canadian history (Brummer, 1978). The attraction in exploring for diamonds is their very high value and the fact mines can be developed in areas without a permanent surface transportation infrastructure because the mine product has very little bulk and can be transported by air. World-wide, the value of diamondiferous kimberlites ranges up to about $800/t though the majority of kimberlite ores are in the $50/t to $100/t range (Kjarsgaard, 2007). Canadian mines rank amongst the world’s most valuable with production to date averaging $267/t (Fig. 9), and reserves averaging about $150/t (Fig. 10). In 2005, Canadian production accounted for approximately 13.5% of world output on a value basis, making Canada the world’s third largest producer by value. With the scheduled openings of the Snap Lake mine in 2007, the Victor mine in 2008, and the Gacho Kué mine in 2011, Canada’s share of world diamond production is expected to increase to over 20% (Perron, 2006).

Diamond mines are the largest private employers in the Northwest Territories, with the creation to 2005 of about 6700 direct and indirect jobs, and have also resulted in the creation of several hundred companies by Aboriginals (Perron, 2006). About $250.7 million was spent on diamond exploration during 2005 (Bouchard, 2006), accounting for 19.3% of total mineral exploration investment attracted to Canada. The bulk of this was directed towards Northwest Territories and Nunavut, again bringing more economic activity to northern communities.

The value of diamond resources is more difficult to calculate than metal resources because the value of the contained commodity is dependent not only on grade and recovery rate but also on quality. The value of recovered diamonds per carat can vary widely between different kimberlite pipes and even within a single pipe. For example, production at Ekati has averaged about $Eq133/t whereas at Diavik it has averaged $Eq366/t. The average value per tonne of ore at the Ekati mine varies from US$40 in the Pigeon pipe to US$186 in the Panda pipe (Kjarsgaard, 2007). To the end of 2005, Canada’s diamond production has been $Eq8.2 billion (Fig. 5), with reserves at $Eq11.8 billion (Fig. 6), and measured and indicated resources are estimated at an additional $Eq15.6 billion (Fig. 7). With additional promising kimberlite pipe clusters under current evaluation, such as at the Fort a la Corne, Saskatchewan and the Foxtrot (Renard), Quebec properties, these resource estimates are likely to substantially increase in the future.

In terms of the value of economic commodities of their ores, magmatic Ni-Cu is the most important deposit type to Canada, thanks mainly to the giant 1850 Ma meteorite impact that produced the unique Sudbury structure. Based on the inflation-adjusted average 1996 to 2005 metal prices, magmatic Ni-Cu deposits have contributed $Eq372.1 billion or 44% of Canada’s total non-ferrous metal and diamond production and $Eq82.5 billion or 45% of 2005 reserves. However, porphyry deposits, mainly of British Columbia, contain the bulk of the measured and indicated resources categories, which amount to $186.4 billion or 44% of Canada’s total. Volcanogenic massive sulphide and lode gold deposits have been the mainstay of Canada’s mining industry and together have supported at least 347 significant mines located in all provinces of Canada except Alberta and Prince Edward Island. Production from VMS and lode gold deposits has amounted to $Eq192.3 billion and $Eq131.6 billion, respectively. Kimberlite diamond deposits, a relatively new mineral deposit type to be mined in Canada, contributed 11% of Canada’s total non-ferrous metal and diamond production in 2005. With several deposits at an advanced stage of evaluation and the deposit type attracting 22% of the $949 million dollars spent on exploration for new deposits in 2005, mining of kimberlite diamonds will be of increasing economic importance in the future. The most valuable ores are the unconformity-related U deposits of the Athabasca Basin, with average production at $Eq540/t and reserves at $Eq4,590/t, compared to the average $Eq130-$Eq180/t for production from underground base metal and gold mines.

The most productive geological environments for mineral deposits are in orogens formed by the collision and accretion of volcanic arcs during the assembly of supercontinents, and this setting hosts nearly all VMS, lode gold, porphyry, and komatiite-associated Ni-Cu deposits. Exclusive of the Sudbury impact structure, mineral deposits of orogens have accounted for 81% of production with 51% coming from Archean greenstone belts. Deposits of epicontinental and intracontinental sedimentary basins account for 16% of production, mainly from Proterozoic U and SEDEX deposits, and Phanerozoic SEDEX and MVT deposits. Deposits associated with anorogenic mafic-ultramafic magmatism, including kimberlite intrusion, account for the remaining 3%.

There has been no production from SEDEX and MVT since 2001, when the Sullivan SEDEX mine closed. Over the past decade the number of VMS and lode gold mine closures has greatly outstripped mine openings for both deposit types, so that at current rates of production reserves for both types will be depleted within ten years. A single mineral deposit is a finite mining resource and it may take decades to unravel the geological complexity of an area to discover new resources to replace them. Providing the geoscience infrastructure necessary for the discovery of new mineral deposits in such a large country as Canada is the key to narrowing the search areas and to attracting the exploration investment to bring about a replenishment of mineral resources.

Many colleagues of the Consolidation of Canada’s Geoscience Knowledge Minerals Synthesis Project contributed either directly or indirectly to this overview of Canada’s mineral resources by freely sharing their expert knowledge and compilations of the various mineral deposit types. The list would include nearly all authors of this volume. Judy Goodwin is thanked for her technical editing and M.D. Thomas and W.D. Goodfellow for their reviews of an early version of the manuscript.

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• Table 1
• Table 2
• Table 3
• Table 4

[Click on an image thumbnail to view a larger image, notice]

 

	Figure 1 Canadian production of non-fuel mineral resources during 2004 by commodity. Only non-ferrous metals and diamonds are discussed in this article. Data from McMullen and Birchfield (2005).
	Figure 2 Simplified geological map of Canada showing geological domains by supercontinent cycle and the distribution of non-ferrous metalliferous and kimberlite diamond deposits. Deposits are colour coded by mineral deposit types and shapes of symbol reflect production status. Only deposits for which a mineral resource has been measured are plotted (see Appendix 1, DVD).
	Figure 3 Recovery rates of metals for different deposit types mined in Canada during the 2002 to 2005 period. The average recovery rate indicated is the value used to calculate mill-head grades from metal production statistics in cases where ore grades or mill-head grades are not reported in conjunction with tonnes of ore milled. Note that there was no production from sedimentary or Mississippi Valley-type deposits during 2002 to 2005 and therefore recovery rates for these deposit types have not been compiled.
	Figure 4 Distribution of metals by deposit type for ores mined in Canada up to the end of 2005. Distribution of metals by deposit type for ores mined in Canada during 2005.
	Figure 5 Stacked bar graphs showing the dollar-equivalent metal content of Canadian ores that were mined up to the end of 2005.
	Figure 6 Stacked bar graphs showing the dollar-equivalent metal content of Canadian ore reserves by deposit type at the end of 2005.
	Figure 7 Stacked bar graphs showing the dollar-equivalent metal content of Canadian measured and indicated mineral resources by deposit type at the end of 2005. These statistics include deposits whose historical 'reserves' were reported prior to 2001 and are not compliant with National Instrument 43-101 Standards.
	Figure 8 Stacked bar graphs showing the dollar equivalent of metal content of Canadian inferred mineral resources by deposit type at the end of 2005.
	Figure 9 Stacked bar graphs showing the dollar equivalent of the average metal content per tonne of ore for Canadian production up to the end of 2005.
	Figure 10 Stacked bar graphs showing the dollar-equivalent of the average metal content per tonne of ore for Canadian reserves at the end of 2005.
	Figure 11 Stacked bar graphs showing the dollar-equivalent of the average metal content per tonne of ore for Canadian measured and indicated resources at the end of 2005.
	Figure 12 Stacked bar graphs showing the dollar-equivalent of the average metal content per tonne of ore for Canadian measured and indicated resources at the end of 2005. These statistics include deposits whose historical ‘reserves’ were reported prior to 2001 and are not compliant with National Instrument 43-101 Standards.
	Figure 13 Schematic illustration of the major geological characteristics of major mineral deposit types that typically occur in continental arc and back-arc environments.
	Figure 14 Schematic illustration of the major geological characteristics of mineral deposit types that typically occur in oceanic arc environment and back-arc spreading centres.
	Figure 15 Schematic illustration of the major geological characteristics of mineral deposit types that typically occur in ore-forming environments within the interior regions of continents.
	Figure 16 Plots of ages versus dollar-equivalent of the total metal contents of deposits of orogens (volcanogenic, lode gold, porphyry) and anorogenic mafic magmatism (magmatic Ni-Cu-PGE), showing the relationships between the geochronological distribution of mineral deposits, major tectonic/magmatic events, and the supercontinent cycle. Ages of magmatic host rocks are from the National Geochronological Knowledge Base (www.ims1.ess.nrcan.gc.ca/geochron), and the remainder is from the databases of Appendix 1 (DVD). Deposits or districts referred to in text are labeled.
	Figure 17 Plots of ages versus dollar-equivalent of the total metal contents of deposits related to combinations of sedimentary process and tectono-thermal events (sedimentary exhalative, Mississippi Valley-type, uranium) and miscellaneous deposits of orogens and intracontinental environments. See text for discussions. Ages are from the databases of Appendix 1 (DVD).
	Figure 18 Geological map of Canada showing the distribution of magmatic Ni-Cu districts and deposits. Legend for the map is as for Figure 2. The diameter of each pie chart is proportional to the dollar equivalent of total metal contained in the district or deposit, and the subdivisions of the pie charts represent the relative amounts in the different categories of mineral resources. A district represents the combined totals of deposits of similar mineral deposit type and age that occur in the same area. The names and total dollar-equivalent metal content are indicated only for districts or deposits with the highest metal contents.
	Figure 19 Histograms showing the distribution by $50/t increments of the average weighted grades of magmatic Ni-Cu deposits for A) production to the end of 2005; B) reserves at the end of 2005; C) measured and indicated resources at the end of 2005.
	Figure 20 Geological map of Canada showing the distribution of volcanogenic massive sulphide districts and deposits. Legend for the map is as for Figure 2. The diameter of each pie chart is proportional to the dollar equivalent of total metal contained in the district or deposit, and the subdivisions of the pie charts represent the relative amounts in the different categories of mineral resources. A district represents the combined totals of deposits of similar mineral deposit type and age that occur in the same area. The names and total dollar-equivalent metal content are indicated only for districts or deposits with the highest metal contents.
	Figure 21 Stacked bar graphs showing the dollar equivalent of the metal content of different resource categories for volcanogenic massive sulphide deposits in Canada for the major geological time intervals. The geographical areas in which most of the deposits in each time category occur are indicated in italics.
	Figure 22 Histograms showing the distribution by $50/t increments of the average weighted grades of volcanogenic massive sulphide deposits for A) pduction to the end of 2005; B reserves at the end of 2005; C) measured and indicated resources at the end of 2005.
	Figure 23 Stacked bar charts for all volcanogenic massive sulphide deposits in Appendix 1 (DVD) showing the dollar-equivalent metal content of total metal resources. Note the difference in scale between (A), (B) and (C). The deposits are arranged in order of dollar-equivalent value. Note the large variation in the relative economic importance of the different metals in different deposits and the lack of correlation between the size (total dollar-equivalent value) and relative metal values.
	Figure 24 Geological map of Canada showing the distribution of lode gold districts and deposits. Legend for the map is as for Figure 2. The diameter of each pie chart is proportional to the dollar equivalent quivalent of total metal contained in the district or deposit and the subdivisions of the pie charts represent the relative amounts in the different categories of mineral resources. A district represents the combined totals of deposits of similar mineral deposit type and age that occur in the same area. The names and total dollar-equivalent metal content are indicated only for districts or deposits with the highest metal contents.
	Figure 25 Histograms showing the distribution by $50/t increments of the average weighted grades of lode gold deposits for A) production to the end of 2005; B) reserves at the end of 2005; C) measured and indicated resources at the end of 2005.
	Figure 26 Geological map of Canada showing the distribution of porphyry districts and deposits. Legend for the map is as for Figure 2. The diameter of each pie chart is proportional to the dollar equivalent of total metal contained in the district or deposit, and the subdivisions of the pie charts represent the relative amounts in the different categories of mineral resources. A district represents the combined totals of deposits of similar mineral deposit type and age that occur in the same area. The names and total dollar-equivalent metal content are indicated only for districts or deposits with the highest metal contents.
	Figure 27 Histograms showing the distribution by $50/t increments of the average weighted grades of porphyry deposits for A) production to the end of 2005; B) reserves at the end of 2005; C) measured and indicated resources at the end of 2005.
	Figure 28 Geological map of Canada showing the distribution of sedimentary exhalative districts and deposits. Legend for the map is as for Figure 2. The diameter of each pie chart is proportional to the dollar equivalent of total metal contained in the district or deposit, and the subdivisions of the pie charts represent the relative amounts in the different categories of mineral resources. A district represents the combined totals of deposits of similar mineral deposit type and age that occur in the same area. The names and total dollar-equivalent metal content are indicated only for districts or deposits with the highest metal contents.
	Figure 29 Bar charts comparing the average weighted grades, expressed as dollar equivalent per tonne, of Canadian sedimentary exhalative deposits with the world-wide average.
	Figure 30 Geological map of Canada showing the distribution of Mississippi Valley-type districts and deposits. Legend for the map is as for Figure 2. The diameter of each pie chart is proportional to the dollar equivalent of total metal contained in the district or deposit, and the subdivisions of the pie charts represent the relative amounts in the different categories of mineral resources. A district represents the combined totals of deposits of similar mineral deposit-type and age that occur in the same area. The names and total $Equivalent metal content are indicated only for districts or deposits with the highest metal contents.
	Figure 31 Geological map of Canada showing the distribution of uranium districts and deposits. Legend for the map is as for Figure 2. The diameter of each pie chart is proportional to the dollar equivalent of total metal contained in the district or deposit, and the subdivisions of the pie charts represent the relative amounts in the different categories of mineral resources. A district represents the combined totals of deposits of similar mineral deposit type and age that occur in the same area. The names and total dollar-equivalent metal content are indicated only for districts or deposits with the highest metal contents.
	Figure 32 Geological map of Canada showing the distribution of selected veins, skarns, iron oxide copper-gold and diagenetic copper deposits. Legend for the map is as for Figure 2. The diameter of each pie chart is proportional to the dollar equivalent of total metal contained in the district or deposit, and the subdivisions of the pie charts represent the relative amounts in the different categories of mineral resources. A district represents the combined totals of deposits of similar mineral deposit type and age that occur in the same area. The names and total dollar-equivalent metal content are indicated only for districts or deposits with the highest metal contents.
	Figure 33 Geological map of Canada showing the distribution of kimberlite diamond deposits and other kimberlite pipes. Legend for the map is as for Figure 2. The diameter of each pie chart is proportional to the dollar equivalent of total metal contained in the district or deposit, and the subdivisions of the pie charts represent the relative amounts in the different categories of mineral resources. A district represents the combined totals of deposits of similar mineral deposit type and age that occur in the same area.