Intrusive Related Gold Deposits

October 2005 Issue 87

Classifying, Distinguishing and Exploring for Intrusion-Related Gold Systems Craig J.R. Hart Yukon Geological Survey P.O. Box 2703 (K-102) Whitehorse, Yukon, Y1A 2C6 Canada E-mail: [email protected] Introduction Intrusion-related gold systems (IRGS) are a newly-defined (1999) deposit classification (based mainly on well-studied deposits in Alaska and Yukon) that is already mired in confusion, nomenclature uncertainty and misapplication. Increasingly, gold deposits are mis-assigned an IRGS classification because: 1) the nomenclature of intrusion-related gold models has been rapidly evolving; 2) the characteristics of the classification are broadly defined to include a wide range of deposit types that overlap with other gold deposit types; and 3) granitoid intrusions are common features of orogenic belts and are an obvious fluid source for any proximal gold occurrence. Ambiguous, poorly understood or poorly-defined deposit model classifications are an economic geologist’s greatest weakness as they result in ineffective exploration strategies. Deposit classifications can be better differentiated from others by using a set of distinguishing features and not characteristics that may be common to many hydrothermal deposit types. Herein, the historical historical evolution evolution of intrusion-related gold deposit concepts is briefly presented, followed by a statement of the current state of intrusion-related gold models, and concluded with a set of characteristics by which IRGS can be

distinguished from other gold deposit types in similar geological settings. Evolution of Intrusion-Related Gold Classifications Intrusion-related gold classifications imply a genetic connection between gold ores and granitic plutons. plutons. These associations rocks have been long recognized (e.g., Agricola, 1556; DeLaunay, 1900; Lindgren, 1933, Spurr, 1923; Niggli, 1929; Emmons, 1926, 1933), but the contemporary geological literature prior to 1990 was essentially devoid of intrusion-related gold models. For example, there is no mention of such milestone contributions on mineral deposit types in models such as the 75th Anniversary Volume of Economic Geology (Skinner, 1981), the U.S. Geological Survey’s Ore Deposit Models (Cox & Singer, 1986), GAC Ore Deposit Models volumes (Roberts and Sheahan, 1988, 1994) or the British Columbia Geological Survey’s original Mineral Deposit Profiles (http://

www.em.gov.bc.ca/mining/GeolSurv/ MetallicMinerals/MineralDepositProfiles/ default.htm). The lack of progress resulted, in part, from the dearth of gold deposit research prior to its price increase in 1980. There were were of course gold-rich skarn deposits, which, by their very nature are intrusion-related, and of course, gold was recognized at Bingham porphyry since mining started in 1906, but Sillitoe (1979) was among the first to emphasize a gold-rich porphyry classification. Early intrusion-related gold classifications were based on a porphyry copper classification. Gold-rich and gold-only porphyry copper systems had been long recognized and were identified and documented by Sillitoe Sillitoe (1979, 1995). Sillitoe (1995) recognized that they represented gold-rich end members and were not a new classification. The “porphyry” nomenclature was exported to refer to intrusion-hosted, low-grade, gold-only deposits at Fort Knox (Hollister, 1992; Bakke,

Inside this issue: 2006 Derry & Gross Winners

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Editorial - D. Duff

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Book Review - Inco comes to Labrador

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Calendar of Events

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Figure 1. Broad distribution of the the Tintina Gold Province (TGP) across Alaska Alaska and Yukon showing individual gold deposits (stars) and notable occurrences mentioned in the text that are considered to be of intrusion-related origin. origin. However, many deposits deposits are not intrusion-related intrusion-related or are at least controversial. The TGP is composed of numerous different gold districts districts with varying forms and ages of mineralization. (Continued on page 4)

2005 2005--2006 GAC MINERAL DEPOSITS DIVISION EXECUTIVE LIST Chairperson: Jan Peter Geological Survey of Canada, 601 Booth Street, Ottawa, ON K1A 0E8; Tel: (613) 992-2376; Fax: (613) 996-3726 Email: [email protected]

Past Chairperson: Hendrik Falck C.S. Lord Northern Geoscience Centre, Box 1500, 4601-B , 52 Avenue, Yellowknife, NT X1A 2R3; Tel: (867) 669-2636; Fax: (867) 669-2725 Email: [email protected]

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Ross Sherlock (2003-2006)

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New Brunswick Department of Natural Resources, P.O. Box 50, 495 Riverside Drive, Bathurst, NB; Tel: (506) 547-2070; Fax (506) 547-7694 Email: [email protected] •

Gema Olivo (2003-2006)

Geological Sciences, Queens University, Tel: (613) 533-6998; Fax: (613) 533-6592 Email: [email protected] •

Kingston,

Bob Cathro (2004-2007)

Cathro Exploration Corporation, 3230 Dogwood Road, RR #1 Chemainus, BC, V0R 1K2; Tel: (250) 246-4738; Fax: (250) 246-4738 Email: [email protected] •

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Rebecca Sproule (2004-2007)

Department of Earth Sciences, Laurentian University, Sudbury, ON, P3E 2C6; Tel: (705) 675-1151, ext. 1325; Fax: (705) 675-4898 Email: [email protected] •

Craig Hart (2004-2007)

Yukon Geological Survey, Box 2703 (K-10), Whitehorse, YK, X1A 2C6; Tel: (867) 667-8508; Fax: (867) 393-6232 Email: [email protected]

Robert Carpenter (2005-2008)

Short Course Coordinator: Steve Piercey

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Mineral Exploration Research Centre, Dept. of Earth Sciences, Laurentian University, Ramsey Lake Road, Sudbury, ON P3E 2C6; Tel: (705) 675-1151 ext. 2364; Fax: (705) 675-4898 Email: [email protected]

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TECK COMINCO Limited, #600 - 200 Burrard Street, Vancouver, BC V6C 3L9; Tel: (604) 640-5373; Fax: (604) 685-3069 Email: [email protected]

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2005 2005--2006 CIM GEOLOGICAL SOCIETY EXECUTIVE LIST President: Damien Duff Ontario Ministry of Northern Development and Mines Willett Green Miller Centre, 933 Ramsey Lake Road Sudbury, ON, P3E 6B5; Tel: (705) 670-5876; Fax: (705) 670-581 Email: [email protected]

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Publications: David Sinclair Geological Survey of Canada, 601 Booth S treet, 6th Floor, Room 675, Ottawa, ON, K1A 0E8; Tel: (613) 992-9810; Fax: (613) 996-3726 Email: [email protected]

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Reg Olson (Awards)

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Andrew Conly (Mineral Deposits search/University Visiting Lecturer)

Re-

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British Columbia Geological Survey, Vancouver Mineral Development Office, Mining and Minerals Division, Suite 300-865 Hornby Street, Vancouver, BC, V6Z 2G3; Tel: (604) 660-2812 Email: Tom. [email protected] •

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1995) and Dublin Gulch (Hitchins and Ossrich, 1995). These examples however, lack numerous defining features of porphyry deposits, such as multidirectional stockworks, disseminations, hydrothermal breccias, and widespread and concentric alteration shells, but served to emphasize the differences in the physical and chemical processes involved in their formation compared to typical porphyry systems. Most of these distinctions result from their deeper level of intrusion compared to porphyry systems. Both Lang et al. (2000) and Rombach and Newberry (2001) recognized that shallower IRGS, such as Shotgun, had characteristics more similar to typical porphyry systems, and therefore emphasized the depth control on intrusion-related characteristics. Sillitoe (1991) first established an intrusion-related classification by defining a “broad spectrum of gold mineralization styles” within epizonal environments. He showed clear evidence of deposit variability and interrelationships within an intrusion-related environment and identified six classes: porphyry, skarn, intrusion-hosted, carbonate-replacement, breccia and vein. Most examples were associated with porphyry copper-style mineralization in magnetite-series (oxidized), I-type intrusions in circum-Pacific island arc settings. As such, these deposits largely represent an “oxidized” intrusion-related gold classification. Newberry et al. (1995) introduced plutonic-hosted gold deposits emphasizing Bi and Te enrichments and correlations with “intrinsic” or genetically-associated gold deposits. Similarly, McCoy et al. (1997) used the term plutonic-related gold deposits to classify a wide range of gold deposit types from several districts through Alaska, and emphasized magmatic fluid evolution of, and differences from, porphyry systems. Their efforts assembled a broad array of characteristics into a single model over a range of depths. Wall and Taylor (1990) and Wall (1999) created a Thermal Aureole Gold model that emphasized proximity to plutons as favourable mineralizing sites due to structures, steep fluid, temperature and chemical gradients and other features. The model indicated numerous possible fluid sources for the deposits, but didn’t specifically imply a direct genetic association with the pluton. An intrusion-related gold vein classification indicated by Sillitoe (1991) was further amplified by Sillitoe and Thompson (1998). The examples used are wide-ranging, and thought to reflect differences in magma chemistry and oxidation state. The broad variations in associated characteristics partly overlap those of orogenic gold veins (Groves et al., 1998) and further emphasize the need for distinguishing characteristics between these two classifications, as was discussed by Sillitoe and Thompson (1998) and Groves et al. (2003). A new intrusion-related class introduced by Thompson et al. (1999) emphasized intrusion-related gold mineralization in regions lacking copper, but known for W and Sn deposits, and having an associated Bi-Te-As-Mo-Sb metal tenor. The deposits are associated with intrusions that are more felsic and more reduced than those highlighted by Sillitoe (1991, 1995) and are partly of Stype character. These systems are clearly distinct from intrusion-related gold deposits associated with chalcophile oxidized magmas. In order to differentiate between the two types, Lang et al. (2000) introduced the term intrusion-related gold “systems” (IRGS), and provided perhaps the clearest refinement of defining characteristics. “System” was emphasized to highlight the wide range of associated gold deposit styles within this scheme. The contribution by Thompson and Newberry (2000) further emphasized the difference between the two classifications by calling them “reduced” IRGS to emphasize the importance of the reduced oxidation state of the associated granitoids and exsolved fluids. Some examples of reduced IRGS granitoids may not be strongly reduced, but are s ignificantly less oxidized than typical granitoids associated with porphyry occurrences. Although gold is traditionally considered to be associated with oxidized intrusions and chalcophile enrichments (e.g., Ishihara, 1981), the reduced character of some gold-related intrusions had been previously recognized for Alaskan examples by Leveille et al. (1988) who also indicated an alkalic association, and by Keith and Swan (1987) for intrusion-related gold deposits in the southwestern USA. A reduced intrusion-related mineral class was also recognized by Rowins (2000) who introduced “reduced porphyry Cu-Au deposits”, using Fort Knox, Shotgun and Telfer as examples, emphasizing them as a base-metal depleted variation of the traditional porphyry theme. Robert (2001) reintroduced syenite-associated gold deposits as Archean examples, but these appear unrelated to other intrusion-related classifications. The reduced IRGS model was mainly developed in response to observations, exploration, discoveries, and research on gold systems across central Alaska and Yukon where they are part of the Tintina Gold Province (TGP) (Figs. 1 & 2), and includes wellstudied examples such as Fort Knox (Bakke, 1995), Dublin Gulch (Maloof et al., 2001), Clear Creek (Marsh et al., 2003), and Scheelite Dome (Mair, 2004). The association of the Tintina Gold Province with intrusion-related gold systems was crystallized by Tucker and Smith (2000) such that TGP gold deposits are broadly considered be entirely intrusion-related. This led Hart et al. (2002) to emphasize that TGP deposits comprise parts of numerous gold districts that formed at several times during the Mesozoic in response to different geological events. They further emphasized that only some of the mineralization is unequivocally intrusion-related, and that many deposits are better characterized as epizonal or shear-hosted because they lack most intrusionrelated characteristics and a causal pluton is not apparent. Hart et al. (2004a) further showed that the TGP is underlain by several different plutonic suites with different metallogenic expressions with the best intrusion-related gold systems (e.g., Fort Knox, Dublin Gulch) being related to the once c ontinuous Fairbanks-Tombstone-Mayo plutonic suite. Misclassified Deposits? Despite the confusion, or perhaps because of it, this recently-developed intrusion-related gold classification is extremely appealing and has been broadly adopted in exploration and research circles. It is the topic of special volumes (Tucker and Smith, 2000; Lang and Baker, 2001), and intrusion-related models have been called upon to describe the genesis of an increasing number of gold deposits and districts throughout the world. The proliferation of the classification has resulted firstly because of the ease of associating a gold deposit with any proximal intrusion, but secondly because the classification is commonly confused and mixed with characteristics of the oxidized intrusion-related gold deposits classification of Sillitoe (1991). The resultant large range of intrusion-related characteristics span a wide range of hydrothermal mineralization characteristics and have resulted in


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Table 1. Historical Development of Intrusion-related Nomenclature and concepts

Name

Main Features

Notable Examples

Reference

Gold-rich porphyry copper deposits

• Recognized gold enrichments as part of porphyry spectrum

Bingham, Marte, Lepanto, Skouries

Sillitoe, 1993

Intrusion-related gold deposits

• Wide variety of epizonal mineralization in the porphyry to epithermal transition

Kidston, Boddington, Salave, Kori Kollo, Muruntau

Sillitoe, 1991

• Six types - skarn, porphyry, replacement, breccia, vein • Chalcophile metal association • Associated with oxidized, I-type intrusions Gold porphyry

• Included as porphyry due to the intrusionhosted, bulk tonnage, low grade nature

Fort Knox, Dublin Gulch,

Bakke, 1995; Hitchins and Orrsich, 1995; Schroeter, 1995

Thermal Aureole Gold

• Proximity to plutons provides structurally favourable sites for mineralization due to thermal and chemical fluxes and multiple fluid sources

Fort Knox, Donlin Creek, Muruntau, Callie, Telfer, Sukhoi Log, Kumtor

Wall and Taylor, 1990; Wall,1999

Plutonic hosted gold, intrinsic

• Noted Bi and Te enrichments and correlations with intrusion-hosted gold deposits

Fort Knox, Ryan Lode, Circle, Vinasale

Newberry et al., 1995

Plutonic related gold

• Emphasized fluid differences from porphyry deposits

Fort Knox, Ryan Lode, Pogo, Cleary Hill, Nixon Fork, Shotgun, True North, Donlin Creek

McCoy, 1997

Intrusion-related gold veins

• Broad spectrum of characteristics reflect the nature of associated magma

Linglong, Ryan Lode, Dongping, Snip

Sillitoe and Thompson, 1998

Syenite-associated

• Archean examples in greenstone belt

Malartic, Beattie, HoltMcDermott

Robert, 2001

Fort Knox, Kidston, Timbarra, Kori Kollo, Mokrsko, Salave

Thompson et al., 1999

• Cu-rich sulphide disseminations Intrusion-related gold deposits in Sn-W provinces

• Included a wide range of deposit styles

Tintina Gold Belt

• Selected papers on a wide range of gold deposits in Alaska and Yukon i ncluded as intrusion-related

Fort Knox, Shotgun, Scheelite Dome, Longline, Pogo, Donlin Creek

Tucker and Smith, 2000

Intrusion-related gold systems

• Emphasis on “Systems”, and differences from porphyry deposits

Fort Knox, Pogo, Brewery Creek, Mokrsko, Salave, Kidston, Timbarra, Vasilkovskoe

Lang et al., 2000

Reduced Cu-Au porphyry

• Copper depleted Cu-Au porphyry

Fort Knox, Shotgun

Rowins, 2000

Reduced intrusion-related gold systems

• Reduced primary oxidation state of intrusion

Fort Knox, Pogo, Donlin Creek, Dublin Gulch

Thompson and Newberry, 2000

Tintina Gold Province

• Excluded gold districts and deposits from intrusion-related classification

Fort Knox, Dublin Gulch, Clear Creek, Scheelite Dome

Hart et al., 2002

• Gold associated with lithophile metal signature

• Divided Tintina Gold Province mineralization into intrusion-related, epizonal and shear hosted (Continued on page 6)


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(Continued from page 5)

numerous vein deposits being assigned an intrusion-related classification. For example, intrusion-related gold mineralization is interpreted within turbidite-hosted orogenic gold systems in the western Lachlan fold belt of Victoria (Miller and Wilson, 2004; Bierlein and McKnight, 2005), in New Zealand’s Otago region (de Ronde et al., 2000), and in the Meguma terrane of Nova S cotia (Kontak et al., 2004). Similarly, intrusion-related gold deposit models have been attributed to deposits in Archean orogenic gold camps including Wallaby (Hall et al., 2001), and some of the Golden Mile orebody (Walshe et al., 2005), both in the Yilgarn craton. Other Phanerozoic examples of intrusion-hosted gold have been stated, such as vein deposits in China’s Shandong Penninsula (e.g., Linglong; Wang et al., 1998) and many deposits (e.g., Donping) along the northern margin of the North China craton (Nie et al., 2004). Even major deposits within the world’s largest orogenic gold province of central Asia, such as Jilau (Cole et al., 2000) and Muruntau (Wall et al., 2004), have been re-interpreted as having intrusion-related origins. These controversial associations of classification are problematic, but are not surprising, as even key deposits within the TGP are controversial. Hart et al. (2002) suggested that this problem resulted from the inclusion of too many deposit types within a single, complex model and suggested a more-refined intrusion-related gold model that excluded controversial epizonal (e.g., Donlin Creek) and shear-hosted (e.g., Pogo) deposits. Both Pogo and Donlin Creek have been variably considered to be orogenic (Goldfarb et al., 2000, 2004, 2005; Groves et al., 2003), and intrusion-related deposits (Newberry et al., 1995; McCoy et al., 1997; Ebert et al., 2000; Smith et al., 1999; Thompson and Newberry, 2000; Rhys et al., 2003) and as such highlight the classification conundrum. The Current Situation Intrusion-related gold deposits, as currently utilized in the geological literature, refer to an incoherent group of deposits with wide-ranging characteristics, granitoid associations and tectonic settings. Beyond those deposits associated with oxidized porphyry-copper systems, the most coherent classification is for reduced IRGS. The characteristics of reduced IRGS deposits, as compiled from Lang and Baker (2001), with contributions from Lang et al. (2000) and Thompson and Newberry (2000) are listed below. Emphasis is on well-studied examples from Alaska and Yukon. A plan perspective of the model presented in Figure 2.

1. 2. 3.

metaluminous, subalkalic intrusion of intermediate to felsic compositions that lie near the boundary between ilmenite and magnetite series; carbonic hydrothermal fluids; a metal assemblage that variably combines gold with elevated Bi, W, As, Mo, Te, and/or Sb and low concentrations of base metals;

Figure 2. General plan model of intrusion-related gold systems from the Tintina Gold Province. Note the wide range of mineralization styles and geochemical variations that vary predictably outward from a central pluton (modified from Hart et al., 2002).


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A

B

Figure 3. Outcrop scale exposure of A) an array of auriferous sheeted quartz veins in the apex of the pluton at Clear Creek, Yukon. Alteration is limited to narrow selvages adjacent to the vein. Marker for scale. B) Sheeted veins at the Fort Knox gold deposit in Alaska, here shown offset slightly by a fracture, are less parallel and slightly more irregular but still do not form multi-directional stockworks, thus distinguishing this deposit type from porphyry deposits. Alteration is limited to thin selvages adjacent to the veins.

4. 5. 6. 7.

a low sulphide mineral content, mostly <5 vol%, with a reduced ore mineral assemblage that typically comprises arsenopyrite, pyrrhotite and pyrite and lacks magnetite or hematite; areally restricted, commonly weak hydrothermal alteration; a tectonic setting well inboard of inferred or recognized convergent plate boundaries; a location in magmatic provinces best or formerly known for tungsten and/or tin deposits

Distinguishing Characteristics of Reduced IRGS Among those characteristics listed above, the first four are common features associated with orogenic deposits and therein lays the potential for misclassification. Only the final two are potentially diagnostic. Below, other distinguishing characteristics are presented. They are mostly designed to differentiate intrusion-related gold deposits, which are a product of local-scale fluids derived from a cooling pluton, from orogenic deposits that are considered to result from crustal-scale fluids derived through metamorphic dehydration (Groves et al., 1998; Stuwe, 1998). Some features exclusively differentiate reduced IRGS. No single characteristic is diagnostic, but a suite of features is most effective to provide evidence of intrusion-related origin. Tectonic Setting Reduced IRGS deposits are best developed in intrusions that were emplaced into ancient continental margins behind accretionary or collisional orogens and subduction-related magmatic arcs. Preferred host strata include reducing basinal miogeoclinal sedimentary or metasedimentary rocks. Gold-related intrusions in Yukon are undeformed as they were intruded millions of years after regional deformation. Metal Zoning Thermal gradients surrounding cooling plutons are steep and result in temperature-dependent concentric metal zones that develop outward from pluton margins for distances up to a few kilometres, or just beyond the thermal aureole. Pluton-proximal gold mineralization may be associated with Bi, Te, and W aureole-hosted mineralization will have an As or Sb tenor, and distal mineralization may be related to Ag-Pb-Zn (Fig. 2). Diverse Deposits Fluids exsolving from cooling plutons are opportunistic and cool quickly, thus depositing metals in several available geological settings. Resulting mineralization is commonly of several different styles: variably intrusion and country-rock hosted consisting of skarns, replacements, disseminations, stockworks and veins (Fig. 2). Gold mineralization is characterized by a wide range of gold grades, with bulk mineable volumes present at the 0.8 to 1.5 gram per tonne level (e.g., Fort Knox). Sheeted Veins The most distinctive style of gold mineralization in reduced IRGS are sheeted arrays of parallel, low-sulphide, single-stage quartz veins which are found over 10s to 100s of metres and preferentially located in the pluton’s cupola (Fig. 3). These veins are unlike multidirectional interconnected stockworks characteristic of porphyry systems or antithetic tensional vein arrays typical of (Continued on page 8)

October 2005 – Gangue No. 87

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orogenic deposits. Pluton Features Mineralizing plutons have “smoking gun” characteristics that indicate the likelihood of generation of hydrothermal fluids. Physical features and geochemical support should exist for high volatile contents, fluid exsolution, evidence of rapid fractionation, zoned plutons, porphyry textures, presence of aplite and pegmatite dykes, quartz and tourmaline veins, greisen alteration, miarolitic cavities and/or unidirectional-solidification textures, preferably in the plutons’ apices (Fig. 4). Redox State Reduced IRGS are associated with felsic, ilmenite-series plutons that lack magnetite, have low magnetic susceptibilities and aeromagnetic response, and have low ferric:ferrous ratios of <0.3. These types of plutons are uncommon in arc and fore-arc settings where orogenic gold deposits are most common. Timing Intrusion-related deposits are coeval (± 2 m.y.) with their associated, causative pluton (i.e., Hart et al., 2004b). Conclusions Beyond the debates and genetic controversies that take place in the geological literature, the main reason for distinguishing between intrusion-related and orogenic gold classifications is the fundamentally different approaches to gold exploration methodology required by each model. Intrusion-related gold classifications are highly varied, mostly poorly constrained and share a large number of associated features with orogenic gold systems. The reduced IRGS model is among the best classified of intrusion-related models and is easily differentiated from other gold deposit classifications for a set of distinguishing characteristics that are particular to fluid generation in a cooling pluton. Acknowledgements This work benefits from discussions and contributions from Richard Goldfarb, John Mair, David Groves and my colleagues at the Yukon Geological Survey. Additionally, comments and a review by Lara Lewis is appreciated. References Agricola, G., 1556. De Re Metallica: Froben Press, Basel; translated into English by Hoover, Herbert Clark and Lou. Henry Hoover; Mining Magazine, London, 1912; (reprinted by Dover Publications, Inc., New York, 1950). Bakke, A.A., 1995. The Fort Knox “porphyry” gold deposit - Structurally controlled stockwork and shear quartz vein, sulphide-poor mineralization hosted by Late Cretaceous pluton, east-central Alaska, in Schroeter, T.A., ed., Porphyry Deposits of Northwestern Cordillera of North America. Canadian Institute of Mining and Metallurgy Special Volume 46, p. 795-802. Bierlein, F.P. & McKnight, S., 2005. Possible intrusion-related gold systems in the Western Lachlan Orogen, southeast Australia. Economic Geology, v. 100, p. 385-398. Cole, A., Wilkinson, J.J., Halls, C. & Serenko, T.J., 2000. Geological characteristics, tectonic setting and preliminary interpretations of the Jilau gold-quartz vein deposit, Tajikistan. Mineralium Deposita, v. 35, p. 600-618. Cox, D.P. & Singer, D.A. (eds.), 1986. Mineral deposit models. U.S. Geological Survey Bulletin 1693, 379 p. de Ronde, C.E.J., Faure, K., Bray, C.J. & Whitford, D.J., 2000. Round Hill Shear Zone-Hosted Gold Deposit, Macraes Flat, Otago, New Zealand: Evidence of a Magmatic Ore Fluid. Economic Geology, v. 95, p. 1025-1048.


Figure 4. Vug at Fort Knox pluton filled with coarse-grained quartz, feldspar, and amphibole. Features such as this are indicative of the pluton having reached fluid saturation and having produced a hydrothermal fluid and typically occur proximal to pegmatitic or aplitic dykes. DeLaunay, L., 1900. Les variations de felons métallifères en profondeur. Reviews Géneral de Science, v. 11, p. 575-580. Ebert, S., Miller, L., Petsel, S., Dodd, S., & Kowalcyk, P., 2000. Geology, mineralization, and exploration at the Donlin Creek project, southwestern Alaska. The Tintina Gold Belt: Concepts, Exploration and Discoveries, British Columbia and Yukon Chamber of Mines, Special Volume 2, p. 99-114. Emmons, W.H., 1926. Relations of metalliferous lode systems to igneous intrusions. Transactions of the American Institute of Mining, Metallurgy and Engineering, v. 74, p. 29-70. Emmons, W.H., 1933. On the mechanism of the deposition of certain metalliferous lode systems associated with granitic batholiths, in Ore deposits of the western States: New York, American Institute of Mining and Metallurgical Engineers, p. 327–349. Goldfarb, R.J., Ayuso, R., Miller, M.L., Ebert, S.W., Marsh, E.E., Petsel, S.A., Miller, L.D., Bradley, D., Johnson, C. & McClelland, W., 2004. The Late Cretaceous Donlin Creek deposit, southwestern Alaska—controls on epizonal formation. Economic Geology, v. 99, p. 643-671. Goldfarb, R.J., Baker, T., Dubé, B., Groves, D.I., Hart, C.J.R. & Gosselin, P., 2005. Distribution, Character, and Genesis of Gold Deposits in Metamorphic Terranes. Society of Economic Geologists, Economic Geology 100th Anniversary Volume. Goldfarb, R.J., Hart, C.J.R., Miller, M., Miller, L., Farmer, G.L. & Groves, D.I., 2000. The Tintina Gold Belt: A global perspective. British Columbia and Yukon Chamber of Mines, Special Volume 2, p. 534. Groves, D.I., Goldfarb, R.J., Robert, F. & Hart, C.J.R., 2003. Gold deposits in metamorphic belts: Overview of current understanding, outstanding problems, future research, and exploration significance. Economic Geology, v. 98, p. 1-29. Groves, D.I., Goldfarb, R.J., Gebre-Mariam, M., Hagemann, S.G. & Robert, F., 1998. Orogenic gold deposits: A proposed classification in the context of their crustal distribution and relationships to other deposit types. Ore Geology Reviews, v. 13, p. 7-27. Hart, C.J.R., McCoy, D., Goldfarb, R.J., Smith, M., Roberts, P., Hulstein, R., Bakke, A.A. & Bundtzen, T.K., 2002. Geology, exploration and discovery in the Tintina gold province, Alaska and Yukon. Society of Economic Geologists Special Publication 9, p. 241-274. Hart, C.J.R., Goldfarb, R.J., Lewis, L.L & Mair, J.L., 2004a. The Northern Cordillera Mid-Cretaceous Plutonic Province: Ilmenite/ Magnetite-Series Granitoids and Intrusion-Related Mineralisation. A Special Issue of Granites and Metallogeny : The Ishihara Volume, Resource Geology, v. 54, no. 3, p. 253-280. Hart, C.J.R., Villeneuve, M.E., Mair, J.L., Goldfarb, R.J., Selby, D.,

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Creaser R.A. & Wijns, C., 2004b. Comparative U–Pb, Re–Os and Ar–Ar geochronology of mineralizing plutons in Yukon and Alaska. SEG 2004 Predictive Mineral Discovery Under Cover, Extended Abstract, J. Muhling et al. (eds.), Perth, Australia, p. 347-349. Hitchins, A.C. & Ossrich, C.N., 1995. The Eagle zone gold-tungsten sheeted vein porphyry deposit and related mineralization, Dublin Gulch, Yukon Territory, in Schroeter, T., ed., Canadian Institute of Mining and Metallurgy, Special Volume 46, p. 803-810. Hollister, V.F., 1992. On a proposed plutonic porphyry gold deposit model. Non-renewable Resources, v. 1, p. 293-302. Ishihara, 1981. The granitoid series and mineralization, in Skinner, B., ed., Economic Geology 75 th Anniversary Volume, p. 458-484. Keith, S.B. & Swan, M.M., 1987. Oxidation state of magma series in the southwestern U.S.: Implications of geographic distribution of base, precious and lithophile metal metallogeny. Geological Society of America Abstracts with Programs, v. 19, p. 723-724. Kontak, D.J., O'Reilly, G.A., MacDonald, M.A., Horne, R.J. & Smith, P.K., 2004. Gold in the Meguma Terrane, southern Nova Scotia. Is there a continuum between mesothermal lode gold and intrusion-related gold systems? Geological Association of CanadaMineralogical Association of Canada Joint Annual Meeting, St. Catharines, Ontario, May 2004, Abstracts Volume 29, p. 374. Lang, J.R. & Baker, T. 2001. Intrusion-related gold systems: the present level of understanding. Mineralium Deposita, v. 36, p. 477-489. Lang, J.R., Baker, T., Hart, C.J.R. & Mortensen, J.K., 2000. An exploration model for intrusion-related gold systems. Society of Economic Geologists Newsletter 40, p.1-15. Leveille, R.A., Newberry, R.J. & Bull, K.F., 1988. An oxidation statealkalinity diagram for discriminating some gold-favorable plutons: an empirical and phenomenological approach. Geological Association of America Abstracts with Program, v. 20, p. A142. Lindgren, W., 1933. Mineral Deposits. McGraw Hill, New York and London, 930 p. Mair, J.L., 2004. Tectonic setting, magmatism and magmatichydrothermal systems at Scheelite Dome, Tombstone Gold Belt, Yukon: Critical constraints on intrusion-related gold-systems. Unpublished PhD thesis, The University of Western Australia, Perth, 197 p., plus appendices. Maloof, T.L., Baker, T. & Thompson, J.F.H., 2001. The Dublin Gulch intrusion-hosted gold deposit, Tombstone plutonic suite, Yukon Territory, Canada. Mineralium Deposita, v. 36, p. 583-593. Marsh, E.E., Goldfarb, R.J., Hart, C.J.R. & Johnson, C.A., 2003. Geology and geochemistry of the Clear Creek intrusion-related gold occurrences, Tintina Gold Province, Yukon, Canada. Canadian Journal of Earth Sciences, v. 40, p. 681-699. McCoy, D., Newberry, R.J., Layer, P., DiMarchi, J.J., Bakke, A., Masterman, J.S. & Minehane, D.L., 1997. Plutonic-related gold deposits of interior Alaska. Economic Geology Monograph 9, p. 191-241. Miller, J. McL & Wilson, C.J.L., 2004. Stress Controls on IntrusionRelated Gold Lodes: Wonga Gold Mine, Stawell, Western Lachlan Fold Belt, Southeastern Australia. Economic Geology, v. 99, p. 941-963. Newberry, R. J., McCoy, D.T. & Brew, D.A., 1995. Plutonic-hosted gold ores in Alaska: Igneous vs. metamorphic origins. Resource Geology Special Issue 18, p. 57-100. Nie, F.J., Jiang, S.H. & Liu, Y., 2004. Intrusion-related gold deposits of North China Craton, People’s Republic of China. A Special Issue of Granites and Metallogeny : The Ishihara Volume, Resource Geology, v. 54, p. 299-324. Niggli, P., 1929. Ore deposits of magmatic origin. Thomas Murby and Co., London, England. Rhys, D., DiMarchi, J., Smith M., Friesen, R. & Rombach, C., 2003. Structural setting, style and timing of vein-hosted gold mineralization at the Pogo deposit, east central Alaska. Mineralium Deposita, v. 38, p. 863-875 Robert, F., 2001. Syenite-associated disseminated gold deposits in the Abitibi greenstone belt, Canada. Mineralium Deposita, v. 36, p. 503-516. Roberts, R.G., & Sheahan, P.A., 1988 (eds). Ore Deposit Models. Geoscience Canada, Reprint Series 3, Geological Association of Canada, 194 p.


Roberts, R.G. & Sheahan, P.A., 1994 (eds). Ore Deposit Models II. Geoscience Canada, Reprint Series 6, Geological Association of Canada, 194 p. Rowins, S.M., 2000. Reduced porphyry copper-gold deposits: A new variation on an old theme. Geology, v. 28, p. 491-494. Rombach, C.S. & Newberry, R.J., 2001. Genesis and mineralization of the Shotgun deposit, southwestern Alaska. Mineralium Deposita, v. 36, p. 607-621. Schroeter, T.G., 1995 (ed.). Porphyry Deposits of the Northwestern Cordillera of North America. Canadian Institute of Mining and Metallurgy, Special Volume 46, 888 p. Sillitoe, R.H., 1979. Some thoughts on gold-rich porphyry copper deposits. Mineralium Deposita, v. 14, p. 161-174. Sillitoe, R.H., 1991. Intrusion-related gold deposits, in Foster, R.P. (ed.), Gold Metallogeny and Exploration, Blackie, Glasgow, p. 165-209. Sillitoe, R.H., 1995. Gold-rich porphyry copper deposits: Geological model and exploration implications, in Kirkham, R.V, Sinclair, W.D., Thorpe, R.I., & Duke, J.M. (eds.), Mineral Deposit Modeling, Geological Association of Canada, Special Paper 40, p. 465- 478. Sillitoe, R.H. & Thompson, J.F.H., 1998. Intrusion-related vein gold deposits: types, tectono-magmatic settings and difficulties of distinction from orogenic gold deposits. Resource Geology, v. 48, p. 237-250. Skinner, B.J. (ed.), 1981. Economic geology seventy-fifth anniversary volume. The Economic Geology Publishing Company, Lancaster, Pa., 964 p. Smith, M.T., Thompson, J.F.H., Bressler, J., Layer, P., Mortensen, J.K., Abe, I. & Takaoka, H., 1999. Geology of the Liese Zone, Pogo property, east-central Alaska. Society of Economic Geologists Newsletter 38:1, p. 12-21. Spurr, J.E., 1923. The Ore Magmas: A Series of Essays on Ore Deposition. McGraw-Hill, New York, 915 p. Stuwe, K., 1998. Tectonic constraints on the timing relationships of metamorphism, fluid production and gold-bearing quartz vein emplacement. Ore Geology Reviews v. 13, p. 219-228. Thompson, J.F.H. & Newberry, R.J., 2000. Gold deposits related to reduced granitic intrusions. Reviews in Economic Geology, v. 13, p. 377-400. Thompson, J.F.H, Sillitoe, R.H., Baker, T., Lang, J.R. & Mortensen, J.K., 1999. Intrusion-related gold deposits associated with tungsten-tin provinces. Mineralium Deposita, v. 34, p. 197-217. Tucker, T.L. & Smith, M.T. (chairs), 2000. The Tintina Gold Belt: Concepts, exploration and discoveries. British Columbia Chamber of Mines, Special Volume 2, 225 p. Wall, V.J., 1999. Pluton-related (thermal Aureole) gold. Short Course Notes, Yukon Geoscience Forum. Wall, V.J., Graupner, T., Yantsen, V., Seltmann, R. & Hall, G.C., 2004. Muruntau, Uzbekistan: a giant thermal aureole gold (TAG) system, in Muhling, J., Goldfarb, R.J., Vielreicher, N., Bierlein, F.P., Stumpfl, E.F., Groves, D.I., & Kenworthy, S. (eds.), SEG 2004: Predictive Mineral Discovery Under Cover; Extended Abstracts, Centre for Global Metallogeny, The University of Western Australia, Publication no. 33, p. 199-203. Wall, V.J. & Taylor, J.R., 1990. Granite emplacement and temporally related gold mineralization. Geological Society of Australia, Abstract Series 25, p. 264-265. Walshe, J.L., Neumayr, P. & Cooke, D.R., 2005. Two boxes we don’t need—orogenic and intrusion-related gold systems, in Hancock, H. et al. (eds.), STOMP 2005, ERGU Contribution 64, p. 143. Wang, L.G., Qiu, Y.M., McNaughton, N.J., Groves, D.I., Luo, Z.K., Huang, J.Z., Miao, L.C. & Liu, Y.K., 1998. Constraints on crustal evolution and gold metallogeny in the Northwestern Jiaodong Peninsula, China, from SHRIMP U-Pb zircon studies of granitoids. Ore Geology Reviews, v. 13, p. 275-292. Editor’s Note: This article is a synopsis of the Boldy award winning paper given at the 2005 GAC-MAC Annual Meeting in Halifax, NS

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AWARD WINNERS Congratulations to the 2006 MDD Award Winners! DUNCAN DERRY AWARD: HOWARD POULSEN , GEOLOGICAL CONSULTANT WILLIAM HARVEY GROSS AWARD: STEPHEN PIERCEY, LAURENTIAN UNIVERSITY These prestigious awards are granted annually by the MDD of GAC and will be presented to the winners at the MDD luncheon to be held at the Annual General Meeting in Montreal (May 2006).


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Volume 13 (2004) of is now available. Future volumes will include special volumes on mineral deposits of the Bathurst Mining Camp, pegmatites, and Proterozoic gold deposits. Volumes 11, 12, and 13 are available to members of MDD at a special affiliated rate of . To purchase these volumes, contact Jo-Anne Watier at CIM (Tel.: 514-939-2710 ext 1311; email: [email protected]).

An Update on the Geology of the Lupin Gold Mine, Nunavut, Canada P.A. Geusebroek and N.A. Duke

An Overview of the ULU Gold Deposit, High Lake Volcanic Belt, Nunavut, Canada E. Flood, P. Kleespies, M. Tansey, H. Muntanion, and R. Carpenter

Geology of the Izok Massive Sulfide Deposit, Nunavut Territory, Canada I.R. Morrison

The Geology and Mineralization of the High Lake Volcanic-hosted Massive Sulfide Deposit, Nunavut C.A. Petch

Geological Setting of the West Meliadine Gold Deposits, Western Churchill Province, Nunavut, Canada R.L. Carpenter and N.A. Duke

Geological Setting of the Meadowbank Gold Deposits, Woodburn Lake Group, Nunavut R. Sherlock, S. Pehrsson, A.V. Logan, R.B. Hrabi, and W.J. Davis

The Setting and Age of the Bermuda Zn-Pb Showing, Grinnell Peninsula, Devon Island: Implications for MVT Mineralization in the Canadian Arctic I. Mitchell, R.L. Linnen, and R.A. Creaser

Nanisivik Mine―A Profitability Comparison of Actual Mining to the Expectations of the Feasibility Study N.R. Burns and M. Doggett

Conjugate Oblique-Extension Veins in Shear and Tensile Fracture Systems at the Komis Gold Mine and Mufferaw Gold Prospect, Northern Saskatchewan B. Lafrance

Get: A Function for Preferential Site Selection of Additional Borehole Drilling A.A. Hassanipak and M. Sharafodin


11

AN OPINION IN PRAISE OF ACTION Various initiatives are underway and being planned to re-vitalize “The North” through geoscience Damien J. Duff, P.Geo CIM Geological Society President Canada’s commodity-based economy has always relied on “The North” as a supplier of base and precious metals to meet global demand. To this end, established mining camps in northwestern Québec, northeastern Ontario, and the NWT, to name just a few, have sustained production at a world-class scale throughout their histories. The Timmins Camp alone is now approaching its 65 th million ounce of gold production, while the storied Kidd Creek Cu-Zn operation proudly recorded its 130 millionth tonne of ore milled in 2005. The problem is, however, that a number of factors are in play across our industry that place continued production at current rates in all our jurisdictions in jeopardy. Increasing energy costs, human resource shortages, capital item purchase delays among others, immediately come to mind as important risks, no question. Less evident to some people, however, may be the risk posed by reserve depletion, particularly in our base metal sector but also in our precious metal mines. Our mines are being depleted at a higher rate than they can replace reserves (Table 1). Further, these existing reserves are saddled by additional challenges, most notably those associated with their increasing mining depth and tough economics. To compound matters, new mines are not being found at a sufficient rate to keep pace. Statistics show that the rate of new discoveries in Canada has dropped significantly in the period 1997-2004 (Figure 1). Faced with these difficulties, I’m glad to report that the Canadian mining industry is not sitting on its hands. Who would have expected it to really? You don’t become best in the world at anything by being paralyzed with fear when the chips are down. Goldcorp in Red Lake, Falconbridge in Timmins, and Inco in Sudbury, to name but a few, can all cite examples of how conditions have forced them to do the “undo-able” (particularly in the field of deep mining) in order to secure the future of some of their best operations. But, interestingly, the public sector is helping too. Initiatives at the municipal, provincial and federal levels are all being undertaken, or are in the advanced planning stages, to help address the problem of reserve depletion and the need for geoscience database enhancement. They have largely been focused in established mining camps, or areas to which I would refer as the near north. Some of the most exciting amongst these many initiatives with which I have some experience are: the Discover Abitibi and Lake Nipigon Geoscience Initiatives in Ontario. Both are a product of an unprecedented level of cooperation among the public and private sectors. In excess of $16 million has been raised to complete a huge number of high value regional surveys in the fabled Timmins-Kirkland Lake corridor as well as the highly prospective geological terrains around Lake Nipigon in northwestern Ontario. The amount of company interest in the results has been significant and, already, diamond discoveries are being directly attributed to results of the former initiative. The amount of support likewise at the municipal level for these projects has been phenomenal. On other fronts as well, the Ontario and federal governments have similarly been pulling their weight. In 2005, the Ontario Budget announced a funding commitment of $15M over three years for geological mapping in the Far North Table 1. Mineral Reserve Levels in Canada (Source: MAC)

Figure 1. New Discoveries in Canada (1997-2004); source PDAC.


Copper

-51%

10.5

Nickel

-31%

21

Lead

-89%

5.5

Zinc

-70%

7

Silver

-65%

7

Gold

-42%

15

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(Figure 2). This area has been generally neglected by all sectors, but new discoveries clearly indicate that the area has immense future mineral potential. For example, De Beers Canada is on track to open a diamond mine 90 km west of Attiwapiskat in 2008, which, when in production, will permanently employ 400 people. As well, some truly phenomenal base metal results are being reported in the same general area by Spider Resources and KWG. My personal view is that The North in all regions of Canada is still a cornerstone for us as an industry. And whereas it is fair to say that our existing camps are becoming more mature, with thus perhaps a lesser chance of significant new exploration success, elsewhere in The North-particularly north of 50 with its huge area of untapped potential, represents the next frontier. But how do we best take advantage of the obvious opportunities it presents? First, we take all necessary steps to document and understand the geology of The North so that we can optimize our chances of economic success. Of necessity, governments must take the lead on this. Where they go, industry will follow. Second, at the municipal level at least, we Figure 2. Far North Mapping Initiative Location. Source: OGS must start thinking of these more remote regions as extensions or even “ catchment areas” around our established mining communities. By this I mean that these communities may have to begin recognizing that decisions made at the higher levels to devote funds and other resources to The North in fact benefit them as well. As an example, the current building boom in Timmins is based in part on the economic spin-offs of the Victor Mine project some 500 km to the north. By helping others in The North, existing mining communities can help themselves. Third, other new opportunities in The North are enhanced by a complimentary infrastructure development plan. Power, roads, and ports are just a few examples of the infrastructure elements, which if available in the North, change everything. The Ontario Mining Association, in its comments to the Ontario Government on the New Mineral Development Strategy for Ontario discussion paper states: “[the strategy] needs to be part of an overall industrial strategy for Ontario, which includes as a component an energy policy and infrastructure enhancement and development (plan) in the Far North”. This is all great stuff admittedly but we geoscientists are really into improving our geoscience d ata collection everywhere, right? Well, here’s the really exciting thing. With the support of the National Geological Surveys Committee (or NGSC for short), and the support of all of Canada’s Mines Ministers, Natural Resources Canada has launched a two year pro ject called Cooperative Geological Mapping Strategies across Canada “to formulate and communicate the federal component of a 10-year implementation plan for CGMS”. This will be, when finally approved, a multi-million dollar commitment (possibly up to $500m over 10 years!) to geoscience. The main strategic goal is: “contributing to new resource-based regional economic development opportunities in frontier areas and the North”. In Ontario at least, this represents a huge opportunity to compliment the Far North Initiative. Kudos all the way around on this one! At the same time, Targeted Geoscience Initiative #3 (TGI-3) is in the planning stages (a MegaTEM survey is already being flown in Québec). This is another federal government-funded initiative “with a focus on base metal reserves in established mining communities” across Canada. The provinces are undertaking their own initiatives in concert with the federal government (the OGS has come out of the gate fast as has, I understand, the Ministére in ˚

(Continued on page 14)


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Québec. I’d be very surprised if other provinces, Manitoba for example, were not also chomping at the bit to attempt to compliment this effort in their respective jurisdictions, and expected total funding levels are $25 million over five years. Technical review sessions have already been held in various locations to discuss possible projects and, pending final budget clearance at the federal level, further work in earnest should commence soon. So, what can we infer from all of these positive developments? Well, the planets seem to be lining up finally (did I also mention that 61% of Canadians, in a poll recently commissioned by the Mining Association of Canada, stated that “the mining industry makes a positive contribution”?!). All the players with an interest in ensuring Canada remains at the forefront of the pack of preferred mining and exploration jurisdictions around the globe are planning and working diligently together. They are addressing geoscience data shortages and other de-enablers to develop ment. As geoscientists with a vested interest in mineral deposits in this country, we all should be adding our voices of support to all levels of government while at the same time ensuring that we convince the powers that be at our respective workplaces of the benefits associated with all of these (and other) initiatives. Our great country and industry were opened up by pioneers and risk takers. Let’s now carry on in this proud tradition by using 21st century tools in conjunction with a 21 st century cooperative spirit and attitude. The challenges to success in The North will always be significant. We need to lay the groundwork now, however, to help overcome them. Through collaboration we all stand a better than reasonable chance of success. Let’s also look for ways to both attract youth to our industry, and nurture and support students of the earth sciences. And finally, let’s be sure to continue to work together to open up The North and help e nsure a bright future for generations present and future !


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The following Symposia are sponsored by the Mineral Deposits Division of the Geological Association of Canada:

SM-2

Diversification of mineral exploration Michel Jébrak (UQAM), Michel Malo (INRS) Contact: [email protected] Sponsored by : Mineral Deposits Division and Divex Description: During the final 20 years of the 20th Century, mineral exploration in Canada, and specifically in Abitibi (Quebec and Ontario), was oriented towards discovering new gold deposits. Meanwhile, production of base metals declined. At the turn of the century, investment in exploration and the rate of new discoveries were also very low. In order to stay competitive, the mineral industry must diversify its exploration strategies and needs new metallogenic models, new tools and new technology. Finding new mines in Canada, including in the little-explored northern latitudes, is more than ever a challenge for the industry. The symposium seeks contributions from researchers in economic geology under the four sub-themes listed below, with the aim to contribute to the diversification of mineral exploration. SM-2A Hydrothermal ore deposits in high-grade metamorphic environments Patrice Roy (MRNFQ), Louise Corriveau (CGC-Québec) SM-2B Sedimentary rock hosted mineral deposits Georges Beaudoin (Université Laval) SM-2C Ore deposits in brecciated rocks (Iron oxide, uranium, porphyry) Michel Jébrak (UQAM) SM-2D New tools and new technologies for mineral exploration Michel Chouteau (École Polytechnique)

SM-2A Hydrothermal ore deposits in high-grade metamorphic environments Patrice Roy (MRNFQ), Louise Corriveau (CGC-Québec) Contact: [email protected]

SM-2B Sedimentary rock hosted mineral deposits Georges Beaudoin (Université Laval) Contact: [email protected]

SM-2C Ore deposits in brecciated rocks (Iron oxide, uranium, porphyry) Michel Jébrak (UQAM) Contact: [email protected]

SM-2D New tools and new technologies for mineral exploration Michel Chouteau (École Polytechnique) Contact: [email protected]

SM-3

Precambrian evolution and mineral deposits of the Canadian and Brazilian shields: similarities and differences Nuno Machado (GEOTOP-UQAM), Gema Olivo (Queen's U.) Contact: [email protected] Sponsored by : Mineral Deposits Division; CAMECO Corporation

FOR MORE INFORMATION ON THE GAC-MAC CONFERENCE , VISIT THE WEBSITE : WWW.ER.UQAM.CA /NOBEL /GACMAC /WELCOME .HTML

October2005– 2005– Gangue October Gangue No.No. 87 87

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CIM GEOSOC Delivering Satisfaction through Quality

GEOSOC PULLS TOGETHER WORLD-CLASS PROGRAM AT 2006 CIM CONVENTION May 14-16th Vancouver Convention Centre Check out one of the premier geological programs anywhere.

Highlights

It takes place over 3 days in May 2006 in downtown Vancouver. Eight technical sessions are being planned covering:

•

Eight ore deposit-type technical sessions

IOCG, Diamonds, Porphyry, Archaean Gold, Uranium, SEDEX , VMS and world-class Nickel deposits. These will be compli-

•

Two (2-day) post conference field trips in British Columbia

mented by two (2-day) post-conference fieldtrips. •

•

•

Student Poster Session Fabulous networking opportunity World-Class Exhibition

Contact person: [email protected] General Contact: [email protected]


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BOOK REVIEW INCO COMES TO LABRADOR Author: Raymond Goldie Published by: Flanker Press Ltd., St. John’s, NL, 2005 Reviewed by: Peter M. Dimmell, P.Geo., St. John’s, NL

“Inco Comes to Labrador ” is another in a long line of books, which describe the discovery and subsequent development of some of the major deposits (and supposed deposits) that have been found over the past twenty to thirty years. Many of these books are written by reporters who covered the stories as they developed such as the Busang “gold deposit” of BreX, the diamond discoveries in the Northwest Territories, or Voisey’s Bay, the subject of this book. Ray Goldie, the author of “ Inco Comes to Labrador ”, is a geologist and a mining analyst with project evaluation training. He therefore brings a different approach and view to the subject that is more related to the movement of share prices and the trials and tribulations of the takeover and development process than other authors who have written on the sub ject. The book also highlights two of the most important aspects of exploration – geological mapping and the work of prospectors. The book starts with a short history of the author, from his education in New Zealand, to his subsequent move to Canada, his work experience, first as a bush geologist with Kennco and others, and then with various “mining houses” as a mining analyst on Bay Street in Toronto. He describes how he learned to value properties and the valuation of pro jects/companies, tongue in cheek, as being a “simple process”. He then describes how it is done by estimating the net present value of various parts of the companies / projects, assuming certain prices and milestones – anything but simple and dependent upon timing. Early nickel/copper/PGE exploration in Labrador by Kennco in the 1970’s, which the author was part of, is described, first in the Kiglaplaits and then in the Harp Lake intrusion where “colour anomalies” (gossans), located by helicopter were followed up, resulting in the discovery of a number of sulphide occurrences, most carrying minor nickel-copper mineralization. This part of the book was interesting to me as I had evaluated much of the assessment work in Labrador as a project geologist for Noranda. I had looked at the Kennco work in the Harp Lake intrusion and had been impressed by the helicopter mapping of the gossans as a simple but expedient way of quickly evaluating areas where there is little tree cover. Goldie also recognized the value of the early mapping work done by geologists Bruce Ryan and Dan Lee who first mapped the Nain Plutonic Suite (NPS) and actually discovered and described the gossan on Discovery Hill, by dedicating the book to them. This gossan, when sampled by Al Chislett and Chris Verbiski in 1993, resulted in the discovery of the Voisey’s Bay deposit. The book provides a good study of stock prices related to various phases of the exploration/acquisition/negotiation process and shows how native/indigenous peoples can delay development unless they are brought into the process early on. He also shows how politics, especially economic nationalism, can affect the development of a deposit and how “expectations” can be raised by promoters such as Robert Friedland, who wanted to get the most for the deposit and politicians such as Clyde Wells and Brian Tobin, who used the discovery to improve their position at the polls and in Tobin’s case, to get himself elected for a second term. The history of the processing part of the project through a smelter/refinery, first promised by Inco, then rescinded, then replaced by the Hydromet process pilot plant, and planned commercial plant, is described and put in the global context of nickel supply and demand. I didn’t particularly like the conversational style of the book whereby the author talks to composite characters, such as Patricia, about the stock price, timing of announcements, etc., feeling that it might have detracted from the story. Also my recollections of various aspects of the discovery and development of Voisey’s Bay, living in Newfoundland and Labrador and being part of the Voisey’s Bay staking rush and subsequent exploration, are sometimes slightly at odds to the author’s. That said, the book is a good summary of the ups and downs related to the development of one of the major nickel-copper deposits in the world today and most likely a new “camp” of deposits, where discoveries will be made for the next 50 plus years. I recommend the book to anyone who wants to look beyond the rhetoric of the politicians and promoters, you will get a better insight into the process of development of a deposit and the pitfalls along the way.

October2005– 2005– Gangue October Gangue No.No. 87 87

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2006 •

March 5-8 - PDAC 2006 International Convention, Metro Toronto Convention Centre, Toronto, Ontario; http://www.pdac/conv/index.html

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April 2-16 - Modular Course in Exploration for Magmatic Ore Deposits , Mineral Exploration Research Centre, Department of Earth Sciences, Laurentian University, Sudbury, Ontario; http://earthsciences.laurentian.ca; contact: [email protected]

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May 14-17 - GAC/MAC Annual Meeting 2006, Université du Québec, Montreal, Québec; http://www.gacmac2006.ca

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May 14-17- Canadian Institute of Mining, Metallurgy, and Petroleum Conference and Exhibition 2006 , Vancouver Convention Center, Vancouver, BC; http://www.cim.org/vancouver2006/

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May 17-21 - Geofluids V, University of Windsor, Windsor, Ontario; http://www.geofluids5.org

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August 21-24 - 12th Quadrennial IAGOD Symposium , “Understanding the Genesis of Ore Deposits - to meet the Demands of the 21st Century,” Moscow, Russia; http://www.iagod.sgm.ru/; contact: [email protected]

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October 22-25 - Geological Society of America Annual Conference , Philadelphia, PA; http://www.geosociety.org/meetings

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September 10-12 - CIM Geological Society Field Conference; Uranium: Athabasca Deposits and Analogues , Saskatoon, SK; http://www.saskuranium2006.ca

2007 •

January 29-February 1 - Mineral Exploration Roundup 2007, The Westin Bayshore, Vancouver, BC; http://www.amebc.ca/roundupoverview.htm; contact: [email protected]

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March 4-7 - PDAC 2007 International Convention, Metro Toronto Convention Centre, Toronto, Ontario; http://www.pdac/conv/index.html

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May 23-25 - GAC/MAC Annual Meeting 2007, Yellowknife, NWT; http://www.nwtgeoscience.ca/gac_mac

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August 20-24 - 9th Biennial SGA Meeting , Dublin, Ireland; http://www.e-sga.org/sga.html

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September 24-30 - Ores and orogenesis: Circum-Pacific Tectonics, Geological Evolution, and Ore Deposits , Tucson, Arizona; http://www.agssymposium.org/

Information for Contributors: The Gangue began as a quarterly publication assembled by the Mineral Deposits Division of GAC, which was distributed to its members in hard copy form. In 2005, MDD and the Geological Society of CIM decided to join forces and jointly publish the Gangue. The Gangue is currently distributed to members of MDD and CIM-GeolSoc as an online publication. The Mineral Deposits Division of the Geological Association of Canada is Canada’s foremost society for promoting the study of mineral deposits by supporting local and national meetings, symposia, short courses and field trips. We sponsor the publication of research relating to ore deposits and metallogeny, and recognize the contributions of outstanding Canadian economic geologists by annually awarding the Duncan Derry and William Harvey Gross medals and the Julian Boldy Certificate.

Publication Schedule: SUBMISSION December 15 March 15 June 15 September 15

DATE January April July October


The objective of this newsletter is primarily to provide a forum for MDD and CIM-Geological Society members and other professionals to voice new ideas, describe interesting mineral occurrences or expound on deposit models. Articles on ore deposits, deposit models, news events, field trips, book reviews, conferences, reprints of presentations to companies, mining groups or conferences, or other material which may be of interest to the economic geology community are welcome. Manuscripts should be submitted by email in WP or WORD format. A printed version should be mailed or FAXed. Illustrations should be camera-ready (ideally as CDR digital files); photos should be of good quality. Short items dealing with news events or meetings can be submitted by FAX, postal mail or email. Contributions may be edited for clarity or brevity.

For Information & Submissions: Kay Thorne — THE GANGUE NB DNR-Minerals PO Box 6000, Room 150 Fredericton, NB E3B 5H1 Email: [email protected] Tel: (506) 453-2206 Fax: (506) 453-3671

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