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Occurrence Details


Occurrence Number
105I 053
Occurrence Name
Op Zones
Occurrence Type
Hard-rock
Status
Deposit


General Information

Primary Commodities: zinc, lead
Aliases: Howards Pass, Selwyn Project, Op West
Deposit Type(s): Sediment hosted Sedimentary Exhalative Zn-Pb-Ag (Sedex)
Location(s): 62.597780 N, -129.652220 W
NTS Mapsheet(s): 105I12
Location Comments: .5 Kilometres
Hand Samples Available at YGS: No

Capsule

Work History

Staked within a large block of OP claims (Y64837) beginning in Sep/72 by Canex Placer Ltd, a wholly owned subsidiary of Placer Development Ltd, following the regional geochemical program that led to the discovery of the Howard's Pass deposit (Minfile Occurrence 105I 012). The property was explored in a joint venture with Essex Minerals Company (U.S. Steel Western Hemisphere Inc) with grid geochemical sampling and mapping in 1973 and 1974. The companies’ staked additional OP claims in Oct/75, and April and May/76 and drilled 2 diamond drill holes (249.9 m) in the summer of 1976 and 7 diamond drill holes (583.7 m) in 1978. Essex's interest was transferred to Cygnus Mines Ltd in Apr/82.

An economic analysis completed at the end of 1982 by Placer and Cygnus concluded that mining the various Howard’s Pass deposits was not economically viable at that time. Placer Development Ltd was amalgamated into Placer Dome Inc in Aug/87. Placer Dome performed cleanup work on the property in 1991.
In Jul/2000 Copper Ridge Explorations Inc acquired an option to purchase a 100% interest in the Howard's Pass property, including this occurrence. The agreement called for a 150 day due diligence followed by a pre-feasibility study. In Sep/2000 Copper Ridge signed a letter of agreement with Billiton Metals Canada Inc for a joint evaluation and possible development of the property. Billiton provided Copper Ridge with $200,000.00 through a private placement, which Copper Ridge used to fund a diamond drill program. Copper Ridge collared 8 diamond drill holes (717 m) on the Anniv Central and Don (Minfile Occurrences 105I 037 and 068) showings as part of their due diligence. In Nov/2000 Billiton informed Copper Ridge that they would not proceed with the proposed joint venture. In Dec/2000 Copper Ridge failed to make a payment as required by the option agreement and the agreement was cancelled.

In May/2005 Pacifica Resources Ltd entered into a Letter of Intent to purchase a 100% interest in the Howard's Pass property for the sum of $10 000 00 spread over 7 years and a commitment to spend a minimum of $3,500,000.00 in exploration expenditures. The agreement was signed between Pacifica and Placer Dome (CLA) a wholly owned subsidiary of Placer Dome Inc (51% owner) and Cygnus Mines Ltd (49% owner). The agreement was formally approved in Aug/2005.
Pacifica Resources drilled 53 diamond drill holes (8,286.9 m) on the Howard's Pass property in 2005. Four holes (668.4 m) were collared on the OP zone to test historical soil sample anomalies and targets unveiled by new geological mapping. The company also carried out Dense Media Separation test work on grab samples collected during previous underground mining programs and from diamond drill core samples. Elsewhere on the property the company carried out regional mapping and soil sampling programs.

In Mar/2006 Barrick Gold Corporation acquired Placer Dome Inc. In May 2006 Barrick sold Placer Dome's 51% interest and other mines and exploration properties to Goldcorp Inc. In Jul/2006 Goldcorp sold Placer Dome's 51% interest in the Howard's Pass property to Terrane Metals Corp. During 2006 Pacifica completed 191 diamond drill holes (40,096.5 m). Six holes (919.4 m) targeted the OP showing. The company also continued Dense Media Separation test work, geochemical sampling, commenced baseline environmental and engineering studies and surveyed all previous drill hole locations, roads and grids in order to digitize and compile all historical geological data.
In Jan/2007 Pacifica released a preliminary assessment report for the development of the Howard's Pass project. The assessment indicates excellent potential for a long life mine, having large-scale, low cost zinc and lead production. The company used the results to help plan future exploration and engineering work.

On January 29, 2007 Pacifica Resources announced a plan of re-organization in which the Howard's Pass project would be spun off to a new company, Selwyn Resources Ltd and the company's remaining properties would be transferred to a new company Savant Exploration Ltd. Pacifica shareholders received shares in Savant Exploration as compensation for the transfer of assets from Pacifica to Savant. The agreement was approved on May 31, 2007 and completed on June 6, 2007 at which time control of the Howard's Pass property, commonly referred to as the Selwyn Project was transferred to Selwyn Resources and the charter of Pacifica Resources was cancelled.
In 2007 Selwyn collared 106 diamond drill holes (37,208.6 m) on the Selwyn Project. Five holes (767 m) targeted the OP showing and one hole (152.4 m) targeted the OP West showing. The company continued environmental and engineering studies, opened a new camp in the Don Valley and closed the camp located near the XY central zone.

On Jan 29, 2008 Selwyn Resources announced an initial mineral resource estimate for the newly designated OP and OP West zones (Pearson and O'Donnell, March 2008), which are still current as of March 2014 (this update). Selwyn collared 13 diamond drill holes (3,856.9 m) on the Howard’s Pass property in 2008 and 10 diamond drill holes (4,214 m) in 2009. None of the holes targeted the OP and OP West zones.

In mid-2009 Selwyn opened discussions with various companies regarding the formation of a possible strategic partnership. The company announced in Dec/2009 that they had signed a binding Framework Agreement with Yunnan Chihong Zinc & Germanium Company Ltd (China), whereby both companies would form a joint venture company to hold all assets associated with the Selwyn project. In return for a 50% interest in the joint venture Yunnan Chihong deposited 100 million dollars in cash irrevocably to a bank account for the joint venture to use to fund development of the Selwyn project. As part of the agreement Yunnan Chihong agreed to fund all of Selwyn Resources direct costs incurred from July 1, 2009 on the Selwyn project.

On January 5, 2010 Selwyn Resources announced that they had engaged Wardrop Engineering Inc to start a Phase 1 work program leading to the completion of a National Instrument 43-101 compliant feasibility study on the Selwyn project. The company hopes to complete the study by the end of 2010.

On August 18, 2010 Selwyn announced the completion of the joint venture with Yunnan Chihong and the formation of a new company Selwyn Chihong Mining Ltd. Selwyn Resources transferred all Selwyn Project claims, equipment, permits and licenses to the new company. At the same time the joint management committee approved in principal a predevelopment budget of 89 million dollars for 2010 and 2011. The money will be directed to the advancement of permitting, completion of the feasibility study and related engineering and resource definition drilling various surface and underground deposits.

A September 2012 report by Kirkham Geosystems lists a global resource for the Selwyn Project, which includes the 2008 estimate for the OP deposits.

Capsule Geology

The Selwyn project (Howard’s Pass project) is located in eastern Yukon and straddles the Northwest Territories border, approximately 350 km northeast of Whitehorse, Yukon and approximately 80 km north-northwest of the former mining town of Tungsten. Over ninety percent of the property lies in the Yukon. To date Selwyn Resources Ltd has identified 15 lead-zinc deposits over a strike length of 37.5 km.

The Selwyn Basin is a region of deep-water offshelf sedimentation that persisted from Late Precambrian to Middle Devonian time. Its basal deposits consist of late Precambrian rift (-) clastics; it is overlain by rift clastics of late Devonian age. On its north-eastern side are time-equivalent shallow shelf strata of Mackenzie Platform. Along its southwestern margin there developed in the Silurian to Devonian a carbonate-clastic shelf the Cassiar Platform. Its southwestern limit is essentially the limit of the miogeocline as presently preserved in the Yukon.

Geological mapping in the Howard’s Pass area has changed significantly since Pacifica/Selwyn Resources Ltd has acquired control of the entire area. Based on various reports released by the companies stratigraphy in the Howard’s Pass area can be summarized as follows. Regionally, Selwyn Basin stratigraphy overlies a basement of Upper Proterozoic to Lower Cambrian maroon to dark blue-grey weathering shale assigned to the Narchilla Formation of the Hyland Group. This unit is conformably overlain by the Upper Cambrian to Lower Ordovician Rabbitkettle Formation. The Rabbitkettle Formation is comprised of an Upper member consisting of grey weathering fine crystalline nodular limestone and a Lower member consisting of grey orange weathering, argillaceous to silty limestones usually limited to beds of less than 10 cm.
Pacifica/Selwyn Resources report the presence of a Transition Formation between the Rabbitkettle Formation and the overlying Duo Formation. This unit identified in drill core, consists of thin interlaminations of grey limestone and buff coloured shale, generally well cleaved.

The Transition Formation is overlain by the Ordovician to Middle Silurian Road River Group which is divided into the Duo Lake and Steel Formations. Various operators working in the area have locally renamed the Duo Formation the Howard’s Pass Formation and have subdivided it into various units. Currently Pacifica/Selwyn Resources have divided the Dou Formation into five member units measuring 300 m thick. The lowest member is a pyritic siliceous shale member, which is overlain by a calcareous mudstone member and a lower cherty mudstone member. These members are overlain by the Active member, a heterogeneous mudstone, limestone, chert that hosts the region’s abundant sulphide mineralization in lamella within a poorly preserved graptolite horizon. An upper siliceous mudstone member tops the formation. The Steel Formation which measures approximately 140 m thick and consisting of a flaggy mudstone containing orange weathered siliceous argillite in beds 10-80 cm thick overlies the Howard’s Pass Formation.

The Road River Group is overlain by the Lower to Upper Devonian Portrait Lake Formation of the Lower Earn Group. The Portrait Lake Formation is comprised of a Lower, Middle and Upper member. The Lower Member consists of a dark brown weathering, silty shale and shale in beds up to 420 m thick. The Middle member consists of a black weathering, massive pebble conglomerate up to 195 m thick and the Upper Member consists of a gun-blue weathering black platy siltstone up to 260 m thick.
The Portrait Lake Formation is overlain by the Upper Devonian to Middle Mississippian Prevost Formation of the Upper Earn Group. It also divided into Lower, Middle and Upper members. The Lower member consists of a grey weathering, dark grey, medium to coarse-grained chert-quartz sandstone up to 160 m thick. The Middle member consists of brown weathering, dark grey, thin bedded shale and siltstone measuring up to 90 m thick and an Upper member consisting of coarse-grained, poorly sorted, chert-quartz sandstone and conglomerate in beds up to 300 m thick. The entire sequence is intruded by various Middle to Late Cretaceous stocks and batholiths ranging in composition from intermediate to granitic assigned to the Selwyn plutonic suite.

Historical drilling and geological mapping carried out by Placer Development suggested that the Anniv and the XY (Minfile Occurrences 105I 037 and 012) sedimentary-exhalative deposits occurred in separate sub-basins along the base of a paleo-slope of the eastern Selwyn Basin. New geological mapping and diamond drilling carried by Pacifica/Selwyn Resources indicates the lead-zinc mineralization hosted by the Selwyn project (Howard’s Pass property) was part of a long-lived, single mineralizing event. As proof of this theory the companies report that the sulphide textures, mineralogy and thickness are similar in each of the 15 deposits identified to date. The hydrothermal fluids that formed the different deposits are also isotopically identical throughout the property. The companies believe the strataform and tabular Active Member was affected by post-depositional structural deformation which likely accounts for the thickening and thinning of the Active Member across the property. Understanding the timing of the faults with respect to each other will aid future exploration programs in locating extensions of the known deposits and locating new resources.

Zinc and lead mineralization at the Selwyn project is hosted in the Active Member and consists of alternating layers of carbonaceous mudstone, limestone and chert, interlayered with stratobound laminated sulphide rich bands. The sulphides are fine grained and dominantly sphalerite and galena with minor pyrite. The mineralized horizon is generally 20 to 30 m thick and is texturally and mineralogically consistent throughout the property.

Ongoing metallurgical test work has confirmed that high-grade zinc and lead concentrate can be achieved. These concentrates have low levels of deleterious elements. Floatation test work indicates that a zinc concentrate grading 55 to 57% can be produced with an overall recovery of about 80% and a lead concentrate grading 65 to 70% lead with a recovery of approximately 70%. The ore will require fine grinding and floatation processing which will include the removal of carbon prior to producing high grade concentrates. Test work completed to date on the application of dense media separation indicates that simple gravity processing could provide an effective means of upgrading run-of-mine ores.

This occurrence consists of the OP zone (occurrence A) and the OP West zone (occurrence B). Both occurrences are located on the western end of the property approximately 30 km west of the Yukon-Northwest Territories border. Canex/Placer Development discovered zinc-lead mineralization similar to the XY deposit (Minfile Occurrence 105I 012) by prospecting in 1975. Follow-up diamond drilling targeted a series of surface showings located at the OP zone. The 1976 drill holes failed to reach their target depths. The 1978 drill holes were more successful with drill hole OP-8 intersecting 4.08% zinc and 1.04% lead over 4.6 m.

Pacifica/Selwyn Resources targeted their diamond drill program to test historical soil geochemical anomalies overlying favourable stratigraphy at the OP zone. Hole OP- 11 intersected 8.3 m grading 2.84% zinc and 1.50% lead. Later holes were completed away from known mineralization and either intersected the hanging wall or low level mineralization within the Active Member. Examination of drill core suggests that the Active Member could be intersected with deeper drilling. Drilling to date has shown that the OP zone dips moderately southwest and is cut by numerous imbricate southwest dipping faults that break up the zone. The OP zone is open in all directions.
The OP West zone is located 3.5 km northwest of the OP zone and has been defined by a single drill hole (OP-017) drilled in 2006, which intersected 8.9 m grading 2.64% zinc and 0.85% lead. Although the grades of the OP and OP West zones are considered lower than other areas of the property, test work demonstrates that dense media separation provides an effective way to increase the over grade.

As of Jan/2008 Selwyn Resources calculated that the OP zone hosts an inferred mineral resource of 1,770,000 tonnes grading 4.18% zinc and 1.29% lead (report by Pearson and O'Donnell, March 2008). The OP West zone hosts an inferred mineral resource of 1 380 000 tonnes grading 2.67% zinc and 0.86% lead. Both calculations employ a 2% zinc grade cut-off.

As of Sep/2010 the entire Howard’s Pass property (consisting of 15 individual deposits) hosts an indicated resource (using a 2% zinc cut-off) of 154,350,000 tonnes grading 5.35% zinc and 1.86% lead and an inferred resource of 234,150,000 tonnes grading 4.54% zinc and 1.41% lead.

A September 2012 report by Kirkham Geosystems lists a global resource for the Selwyn Project, which includes the 2008 estimate for the OP deposits. Calculated at a 2% Zn cut-off grade, the Global INDICATED Mineral Resource for the Selwyn Project is calculated at 185,570,000 tonnes grading 5.2% Zn and 1.79% Pb for a contained total of 21.26B lbs (9.64B kg) Zn and 7.3B lbs (3.3B kg) Pb. The Global INFERRED resource is listed at 237,860,000 tonnes grading 4.47% Zn and 1.38% Pb for a contained total of 23.45B lbs (10.63B kg) Zn and 7.22B lbs (3.27B kg) Pb.

Location Map

Last Updated: Aug 2, 2018

Work History

Year Work Type Comment
2012 Studies: Resource Estimate Kirkham Geosystems, Sept 27 2012. Includes global resource for Selwyn Project.
2010 Studies: Feasibility
2008 Studies: Resource Estimate Pearson and O'Donnell, March 2008. Resource still current as of March 2014.
2007 Drilling: Diamond 6 holes, 919.4 m. Five holes collared on OP zone, one hole collared on OP West zone.
2006 Drilling: Diamond 6 holes, 919.4 m
2006 Lab Work/Physical Studies: Metallurgical Tests Dense Media Separation testing of samples from OP zone.
2005 Drilling: Diamond 4 holes, 668.4 m
2005 Geochemistry: Soil Property wide.
2005 Geology: Bedrock Mapping Property wide.
2000 Drilling: Diamond 8 holes, 717 m Conducted by Copper Ridge on other parts of property as part of due diligence.
1982 Pre-existing Data: Research/Summarize Economic analysis concluded that mining was not economic at that time.
1978 Drilling: Diamond 7 holes, 583.7 m
1976 Drilling: Diamond 2 holes, 249.9 m
1973 Geology: Bedrock Mapping
1973 Other
1972 Other

Regional Geology - Terrane

Group: Ancestral North America
Affinity: W Laurentia
Name: North America - basinal strata
Realm: Laurentia


Regional Geology - Bedrock

Supergroup:
Group/Suite: Earn
Formation: Portrait Lake/Prevost
Member:
Terrane: Laurentia
Period Max: Devonian
Age Max: 385 MA
Period Min: Carboniferous
Age Min: 345 MA
Rock Major: siltstone/sandstone/conglo
Rock Minor: barite/limestone
Reference: Gordey (1992) - GSC Map 1762A
Geological Unit (1M): DME
Geological Unit (250K): DME1

Assessment Reports that overlap occurrence

Report Number Year Title Worktypes Holes Drilled Meters Drilled
092875 1978 [Diamond Drilling on OP Claims] Diamond Drilling 6 498
090312 1977 Report on Geological Mapping and Geochemical Surveys Silt Geochemistry, Soil Geochemistry, Bedrock Mapping Geology
097005 1976 Final Report on the 1976 Exploration Program at Howards Pass, Yukon Access Road Development, Surface, Diamond Drilling, Soil Geochemistry, Bedrock Mapping Geology, EM Ground Geophysics, Gravity Survey Ground Geophysics, Surveying Other, Mechanical Trenching 70 9501.23
097007 1975 Final Report on the 1975 Exploration Program at Howards Pass, Yukon Air Strip Development, Surface, Diamond Drilling, Soil Geochemistry, Bedrock Mapping Geology, Prospecting Other, Mechanical Trenching 19 4013.45
061275 1973 Report on the Geology and Mineralization Summit Lake Area, Y.T.-N.W.T. Silt Geochemistry, Soil Geochemistry, Regional Bedrock Mapping Geology

Related References

Number Title Page(s) Document Type
ARMC008071 Compilation map outlining geology and mineral deposits in Selwyn Basin - Selwyn project Geochemical Map
ARMC016512 Geochemical results overlay map - 105I/12 Geochemical Map
ARMC016513 Geochemical sample stations overlay map - 105I/12 Geochemical Map
ARMC016514 Geochem samples overlay maps - 105I/12 Geochemical Map
094637 Assessment Report Describing Prospecting, Geochemical Sampling and Diamond Drilling on the Selwyn Project Assessment Report
094657 Assessment Report Describing Prospecting, Geochemical Sampling and Diamond Drilling on the Selwyn Project Property Assessment Report
092875 [Diamond Drilling on OP Claims] Assessment Report
Citations
Dawson, K.M., 1990. Regional geological setting of selected mineral deposits of the Northern Cordillera. In: Mineral Deposits of the Northern Canadian Cordillera, Yukon-Northeastern British Columbia, J.G. Abbott and R.J.W. Turner (eds), 8th IAGOD Symposium, Field Trip NO. 14 Guidebook, Geological Survey of Canada Open File 2169, p. 6.
Goodfellow, W.D. and Jonasson, I.R., 1983. Environment of formation of the Howard's Pass (XY) Zn-Pb deposit, Selwyn Basin, Yukon. In: Mineral Deposits of Northern Cordillera, J.A. Morin (ed.), Canadian Institute of Mining and Metallurgy, Special Volume 37, p. 19-50.
Jonasson, I.R. and Goodfellow, W.D., 1983. Sedimentary and digenetic textures, and deformation structures within the sulphide zone of the Howard's Pass (XY) Zn-Pub deposit, Yukon and Northwest Territories. In: Mineral Deposits of Northern Cordillera, J.A. Morin (ed.), Canadian Institute of Mining and Metallurgy, Special Volume 37, p. 51-70.
Kirkham Geosystems, Sept 27 2012. Update for Don Deposit Mineral Resource Estimate, for Selwyn Resources Ltd.
Morganti, J.M., 1979. The geology and ore deposits of the Howard's Pass area. Unpublished Ph.D. thesis, University of British Columbia.
Pearson and O'Donnell, March 2008.Update Resource Estimate Report for the Selwyn Project, Yukon-NWT Canada, for Selwyn Resources Ltd.
Last Updated: Aug 2, 2018

Resource/Reserve

Year Zone Type Commodity Grade Tonnage Amount Reported Amount 43-101 Compliant Cut-off
2012 Selwyn Global Resource (Open Pit & Underground) Indicated zinc 5.2 % 185,570,000 9,643,373,786 Yes Yes 2% Zn
2012 Selwyn Global Resource (Open Pit & Underground) Inferred zinc 4.47 % 237,860,000 10,636,741,076 Yes Yes 2% Zn
2012 Selwyn Global Resource (Open Pit & Underground) Inferred lead 1.38 % 237,860,000 3,274,936,911 Yes Yes 2% Zn
2012 Selwyn Global Resource (Open Pit & Underground) Indicated lead 1.79 % 185,570,000 3,311,224,301 Yes Yes 2% Zn
2008 OP WEST ZONE (OPEN PIT) Inferred zinc 2.67 % 1,380,000 36,287,389 Yes Yes 2% Zn
2008 OP WEST ZONE (OPEN PIT) Inferred lead .86 % 1,380,000 13,607,771 Yes Yes 2% Zn
2008 OP ZONE (OPEN PIT) Inferred zinc 4.18 % 1,770,000 72,574,779 No Unknown 2% Zn
2008 OP ZONE (OPEN PIT) Inferred lead 1.29 % 1,770,000 22,679,618 Yes Yes 2% Zn

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