The COSMOPOLITAN prospect is located in the northern region of the 4.5 kilometre long Bralorne Gold Mines deposit trend, approximately 1 kilometre west of Mead Lake and 1.7 kilometres north-northeast of Bralorne, B.C.

The Bralorne-Pioneer gold deposit is considered to belong to the mesothermal, orogenic, or greenstone-hosted quartz-carbonate gold vein deposits. These deposits form within metamorphic rocks in shallow to mid crustal depths of 5 to 15 kilometres. Quartz-carbonate veins are hosted in moderately to steeply dipping brittle-ductile shear zones and locally in shallow dipping extensional fractures. The approximately 4.5 kilometre long Bralorne-Pioneer gold-bearing vein system is a structurally-controlled hydrothermal gold deposit developed within a lensoidal block of relatively competent host rocks bounded by regional scale faults and less competent rocks.

The King Block area, including the King mine and Cosmopolitan prospect, consists mainly of Bralorne Diorite and lesser bedded mudstone and metasediments. Minor lenses of volcanic greenstone and sheared ultramafic rocks are also present. The deposit is truncated to the northwest by a major north-trending fault. Pre-mineralization mafic to felsic fine-grained dikes are common. Banded quartz veins are typically hosted within the diorite and sometimes in the sediments or at contacts between the two. The major historically known veins in the King Block are the King Vein, the C Vein, the Shaft Vein and the North Vein (Assessment Report 40623).

The area of the Peter Vein is underlain by Mississippian to Jurassic Bridge River Complex (Group) and Upper Triassic Cadwallader Group sediments and volcanics which are transected by a major north trending, steeply southwest dipping fault known as the Cadwallader Break. The fault is a deep-seated crustal structure related to the Fraser fault system to the south. The fault is intruded by small granitic to ultramafic stocks and dikes. Diorite to gabbro of the Permian Bralorne Igneous Complex, in which most of the quartz veins are hosted, intrudes the Cadwallader Break as an elongate body.

In 1973 additional work was started in the area of the Peter Vein where surface work indicated potential mineralized structures. Surface drilling and trenching located the Peter Vein and in 1987 an adit was collared to intersect the structure about 33 metres below surface; 65 metres of drifting on the vein averaged 13 grams per tonne gold across an average width of 3.4 feet (Assessment Report 27355).

The Peter Vein was first opened up on surface in 1987, but apparently had been known from the underground development of the Bralorne mine's King Vein. Trenching has now traced the vein along its northwest strike for over 550 metres, with widths varying from a few centimetres to 3 metres. One sample graded 102.86 grams per tonne gold over 2.8 metres (George Cross News Letter No.111, June 10, 1991). The best intersection from 14 holes drilled on the vein graded 16.46 grams per tonne gold over 2.7 metres (George Cross News Letter No.111, 1991). Further drilling proved the existence of the vein to a depth of 167 metres.

Two veins on the Loco (Cosmopolitan) prospect are estimated to contain 362,800 tonnes grading 17.2 grams per tonne gold (Information Circular 1995-1, page 15). The Peter Vein was drifted along a strike length of 35 metres on the 800 level, 305 metres below the surface (T. Schroeter, personal communication, 1996). About 1814 tonnes of ore were extracted from surface on this zone late in 1996 with grades of 3.4 to 10.2 grams per tonne gold. Included in this material is unknown tonnage of sulphide enriched quartz vein material assaying 572.4 grams per tonne gold with silver values of 1371 grams per tonne.

The parallel Millchuk Vein, 300 metres to the north, has been traced by trenching for 670 metres, with the best chip sample grading 10.29 grams per tonne gold over 1.5 metres (George Cross News Letter No.111, 1991).

In 1995, Bralorne Pioneer Gold Mines Ltd., and partner International Avino Mines Ltd., with support from the Explore B.C. Program, carried out an extensive exploration program including trenching and 650 metres of surface diamond drilling in 7 holes on the Maddie zone resulting in the discovery of new veins. Underground work on the 800-level consisting of 233 metres of drifting, 100 metres of crosscuts and 544 metres of diamond drilling in 4 holes traced the Peter and Big Solly veins to and beyond a crossfault (Explore B.C. Program 95/96 - A32).

Bralorne-Pioneer Gold Mines Ltd. performed trenching exploration during 2002 and extended the Peter Vein by 366 metres to the west. Drilling began on the Peter Vein in November, 2002 and 9 holes were completed. Hole #8 returned an assay of 52.28 grams per tonne gold over 1.37 metres.

In 2003, Bralorne-Pioneer Gold Mines Ltd resumed construction of a 125 tonne-per-day pilot plant test mill and began construction of a tailings pond. Trenching and drilling were done in the area of the Peter, Cosmopolitan and Big Solly veins on the Loco property. Bralorne also did rehabilitation work on the 800 level in the Bralorne mine. In 2004, a drilling program consisted of 15 NQ holes totaling 1751.5 metres and was designed to provide additional information on the Peter Vein and associated structures in the area beneath the upper level workings and also along strike to the north and south. Bralorne also did underground development to prepare a stope on the Peter Vein on the 800 level of the King mine workings, and drove a decline from the 4230 level to access a new level 30 metres deeper.

In 2004, Bralorne completed construction of a tailings pond to allow five years of production, and began test milling using a small (approximately 100 tonne-per-day) gravity/flotation pilot plant. As of mid-August more than 10 000 tonnes had been processed through the plant, producing about 141 dry tonnes of concentrate. Most of the material processed was from low-grade stockpiles with some additional material coming from the Upper Peter Vein (4230 adit) on the Loco (or Cosmopolitan) property. A small amount of dore gold was produced onsite, and about 20 tonnes of flotation concentrate was shipped. Bralorne also did underground development to prepare a stope on the Peter Vein on the 800 level of the King mine workings, and drove a decline from the 4230 level to access a new level 30 metres deeper.

The following resource estimates were reported in The Northern Miner (April 4, 2005). It is not known if they are NI 43-101 compliant. The measured resource in the Peter Vein comprises 3,425 tonnes grading 8.4 grams gold per tonne. The Peter vein has been drifted on top and bottom with samples taken at 1.8 metre intervals across the exposed vein. The upper Peter Vein contains another 22,738 tonnes grading 9.7 grams gold in the inferred category.

In 2015, the focus of the underground development was initially to advance the BK Mine 3750 and 3850 Level access drifts towards the Alhambra Vein. Three drill holes targeted the Alhambra Vein extensions to the West for a total of 371.25 metres. Drilling highlights include an intercept of 17.45 grams per tonne gold over a core length of 0.3 metres (0.2 metres true width) in hole SB15-001 on the Alhambra vein (Kirkham, G. (2016-10-20): NI 43-101 Technical Report – Bralorne Gold Mine).

In 2018, Bralorne Gold Mines (Talisker Resources) ran aggressive programs to evaluate the potential of underexplored portions of the property, including digitization of known information, data mining and integration into 3D visualization software. Thirteen diamond drill holes in the Bralorne East and Pioneer Blocks (Ida May, Coronation and Pioneer areas) were completed from surface, totaling 3045.87 metres to delineate new resources on existing veins within the inferred resources category (Assessment Report 38967).

In 2021, Talisker drilled 31 diamond drill holes totaling 16,814.5 metres and 3 reverse circulation holes totaling 1,343 metres in the BRX and Bralorne Mine blocks, as well as an airborne magnetic, VLF-EM and radiometric surveys. In 2022, a further 34,425.1 metres of infill drilling in 80 holes were completed extending from the B King area (approximately 750 metres southwest of the Cosmopolitan) in the northwest to the Pioneer Block in the southeast (Assessment Report 40623). In latter 2022, 2458 metres were drilled in 3 holes to extend boundaries of known veins along strike and at depth (Assessment Report 41719).

*Note that the Cosmopolitan prospect has vein systems in common with the King/BK mine. See B King Minfile.

*See BRALORNE (Minfile 092JNE001) for more on exploration, geology and mineral resource estimates for the Bralorne Gold deposit belt.