The Alwin deposit is located immediately east of Little O.K. Lake in the Highland Valley.
The area is situated within the central core of the early Jurassic–late Triassic Guichon Creek Batholith. It is hosted entirely by Bethsaida phase granodiorite, which is locally fractured and altered by potassium feldspar and sericite, causing red and green discolouration, respectively. Steep-dipping aplite dikes and lenses, visible in the first 210 metres of the adit, strike east and northeast. Elsewhere and locally, they form a network of veins in brecciated granodiorite. Quartz-plagioclase porphyry dikes, up to 6 metres wide, strike north and dip steeply east. These dikes are sericite and calcite-altered, weakly mineralized and offset by east- striking ‘ore faults’.
Regional faults near the Alwin mine strike north and east. In the mine, faults range from narrow shears to “strong gougy faults” up to 60 centimetres wide. The largest fault is north- and northeast-striking, moderately dipping, 60 centimetres wide, and offsets ore zones as well as ‘ore faults’. ‘Ore faults’ contain a sericitic or clay gouge, strike east and dip steeply within high-grade bodies.
Fractures occur in two main sets; one strikes north-northeast and dips moderately east, the other strikes east and is nearly vertical. The fractures may or may not be mineralized. East-dipping fractures locally contain mineralized quartz veins up to 10 centimetres wide.
The deposit is defined as an east-trending, steeply dipping zone or lens, approximately 457 metres in length by 152 metres in width and 244 metres in depth and is open at depth and to the east. At least six ore zones have been identified with two dominant trends: 075 to 090 degrees and 290 to 305 degrees. In plan and section, the zones pinch, swell and digitate; mined widths range from 1.5 to 10.7 metres. Chalcopyrite and bornite occur as disseminations, clots and discontinuous massive veins and veinlets with minor pyrite and trace chalcocite. Small amounts of gold and silver are reported (Exploration in British Columbia 1980). Gangue minerals are mainly flaky sericite and quartz with lesser amounts of chlorite, specularite, calcite and tetrahedrite-tennantite. Occasional massive epidote pods are found adjacent to ore. Post-ore iron carbonate veins are common in ore zones. Locally, north-trending and east-dipping porphyry dikes, up to 6 metres in width, offset the ore zones vertically and laterally.
Lower- grade mineralization is related to fracturing. Mineralized fractures contain minor chalcopyrite, bornite, molybdenite, pyrite, specularite and in one place galena in vuggy quartz and calcite veins. Potassium feldspar, chlorite, sericite and possibly kaolinite occur as gangue minerals.
The surface projection of the No. 4 North zone, as exposed by trenching on the IOU claim, consists of malachite with lesser azurite and minor disseminated chalcopyrite mineralization adjacent to a sericite- and clay-altered, limonite-stained shear zone in a sericite- and silica-altered granodiorite. The zone has been followed continuously for a width of up to 7 metres and for 84 metres along a strike of 105 degrees that dips nearly vertically. In 1993, trench T93-04 yielded 1.09 per cent copper and 1.25 grams per tonne silver over 6 metres (Assessment Report 23151).
Chalcopyrite and bornite mineralization are also reported to be exposed in trenches, southwest of the Alwin adit, on the Apex (L.3645) Crown grant.
Underground development on the O.K. (L.3644), I.O.U. (L.3643) and Apex (L.3645) Crown-granted claims includes three adit portals at elevations of approximately 1405, 1540 and 1600 metres; a shaft at 1635 metres and approximately 2700 metres of drifting and stoping occurring on at least seven levels or sub-levels, including incline and decline drifts between the 1540 metre level adit and the surface. The lower adit portal, referred to as the Alwin adit, is located on the eastern side of the Apex (L.3645) Crown grant, whereas the upper two adits (Upper and Lower O.K. adits) are located to the northeast on the eastern side of the O.K. (L.3644) Crown grant. Open stopes, on the 5 and 3 East zones, have been driven to the surface on the O.K. (L.3644) and I.O.U. (L.3643) Crown grants.
The presence of high-grade copper mineralization was first noted on the Alwin property in the late 1800’s. Early production during 1916 through 1918, under the name of the Chataway Mine, totalled 1372 tonnes yielding 240,288 kilograms of copper and 27.03 kilograms of silver. By 1919, development included a 66-metre adit, a 60-metre winze and a total of 225 metres of underground development.
In 1961, Royal Canadian Ventures completed a program of geological mapping and ground magnetic surveys on the area. In 1967, Arlington Silver completed an induced polarization survey on the area. During 1967 through 1970, Alwin Mining Co. completed a program of extensive surface and underground diamond drilling, including 119 holes and 1400 metres of underground development. In 1971, drilled ore reserves were reported to total 1,078,742 tonnes grading 2.33 per cent copper, 11.8 grams per tonne silver and 0.10 gram per tonne gold (Property File - Alwin Mining Company Ltd. [1970-05-01]: Feasibility Report for 500 Ton Per Day Mining and Concentrating Plant with Related Services and Facilities - Alwin). In 1971 and 1972, production briefly resumed and a total of 75,852 tonnes were milled and mined yielding 5.69 kilograms of gold, 618.55 kilograms of silver and 1,151,858 kilograms of copper. Also, during this time, 1000 metres of underground development and 4375 metres of underground diamond drilling were completed.
In 1973, Selco Mining Corp. optioned the property and completed 11 underground drill holes, totalling 905 metres. During 1974 through 1979, the O.K. Syndicate completed an additional 205 underground drill holes, totalling 10,330 metres.
In 1980 and 1981, DeKalb Mining Corporation produced at a rate of 700 to 800 tons per day with underground production totalling 155,352 tonnes yielding 40.544 kilograms of gold, 2074.33 kilograms of silver and 2,394,090 kilograms of copper. During this time, underground development extended down to the 1400 metre elevation, 270 metres below surface; 67 underground drill holes, totalling 3935 metres, and 9 surface drill holes, totalling 905 metres, were completed. Reserves, upon closing, were reported at 262,667 tonnes grading 3.21 per cent copper (Assessment Report 23151). Other reports indicate that an estimated diluted mineable reserve of 390,010 tonnes grading 2.5 per cent copper remained in the No. 4 North zone (Property File - The Northern Miner [1995-01-23]: News Clipping - Claimstaker moves underground at Alwin). The property was subsequently purchased by F.D. Miller and stripped of buildings and machinery. The land was reclaimed and the mine openings sealed.
In 1993, J-Pacific Gold Inc. (then, Claimstaker Resources) optioned the Alwin property and subsequently earned a 100 per cent interest, subject to a 2.5 per cent net smelter return royalty payable to F.D. Miller. J-Pacific trenched the projected surface exposure of the No. 4 North zone. In January 1995, the underground workings were re-opened and 30.4 metres of development was completed to help prepare the No. 4 - North orebody for future production. Two composite bulk samples, weighing approximately 110 kilograms each, were collected from the 54-75 and 53-50 raises on the No. 4 North zone.
In 1995, Claimstaker Resources Ltd. shipped approximately 2,720 tonnes of oversize, high-grade boulders containing 1.3 per cent copper to Afton (Information Circular 1996-1, page 17). Existing ore reserves are 390,053 tonnes grading 2.5 per cent copper (T. Schroeter, personal communication, 1995).
In 2000, Claimstaker Resources completed a 3.1 line-kilometre ground magnetic survey. In 2002, the Alwin property was reported to have an inferred resource of 390,090 tonnes of ore, using a 25 per cent dilution factor, grading 2.5 per cent copper, 11.7 grams per tonne silver and 0.69 gram per tonne gold (J-Pacific Gold website, March 2002). This resource requires confirmation.
In 2006, Max Investments Ltd. completed a program of soil sampling and a 35.0 line-kilometre induced polarization survey on the area. Four rock samples were collected at this time and yielded 1.76 per cent copper from the Upper Adit portal, 2.38 per cent copper from a trench and 12.26 per cent copper, 12.8 grams per tonne silver and 0.10 gram per tonne gold from a dump sample (Assessment Report 28783).
In 2008, San Marco Resources Inc. completed seven surface diamond drill holes, totalling 1304.5 metres, on the area. This work extended the known mineralized structure along strike to the east (holes 08-01 and 08-02) and at depth (holes 08-03 and 08-04), though intersections to the east were reported to be less than the grade-thickness of the historic main zone, whereas at depth the grade-thickness was equal or better than those historically mined. The best hole (08-04) yielded 1.51 per cent copper over 19.6 metres, including 6.34 per cent copper over 3.6 metres, before intersecting underground workings, while intercepts in hole 08-02 included 0.90 per cent copper over 6.7 metres, 0.48 per cent copper over 4.0 metres and 0.25 per cent copper over 10.5 metres (Assessment Report 30283).
