The Fors occurrence is located approximately 1.7 kilometres west of the southern end of Monroe Lake.
The area is underlain by clastic rocks of the Helikian Purcell Supergroup. The units are dominantly siliclastic sedimentary rocks of the Lower and Middle Aldridge formations. In the south east, the right-lateral reverse Moyie fault juxtaposes Aldridge rocks with a conformable package of younger Creston Formation siltstones and argillites. The Proterozoic Moyie Intrusions are gabbro sills and intrude the Lower Aldridge Formation and the lower part of the Middle Aldridge Formation. Regional metamorphism is upper greenschist facies.
Two styles of mineralization are documented on the property. The first style comprises base metal sulphide mineralization related to a shear zone in Middle Aldridge Formation quartzite and quartz- feldspar arenite with minor argillaceous intercalations. The shear zone strikes 035-045 degrees and dips approximately 40 degrees northwest. The sulphide mineralization and related silicification at the Main showing occur together and are generally restricted to the zone of shearing or within a few metres of it. Argillic and sericitic alteration of the clastic rocks is common and consists of weak to complete replacement of feldspar in the matrix by white mica and clay minerals. The sulphides occur as bedding parallel disseminations and replacement patches and comprise pyrite, pyrrhotite, sphalerite, galena and chalcopyrite, in decreasing order of abundance.
The second style of mineralization comprises minor sulphide mineralization (dominantly pyrite and sphalerite with minor chalcopyrite) occurring in quartz veins hosted by Moyie metagabbro sills and to a lesser extent in Aldridge units. The vein material is typically vuggy, medium to coarse- grained and highly fractured, with much iron and manganese staining.
Grab samples from the Main showing assayed a range of values: 15 to 130 grams per tonne silver, 0.41 to 4.2 per cent lead, 0.21 to 7.1 per cent zinc and 0.024 to 1.45 per cent antimony (Assessment Report 19809).
In 1966, Cominco completed a program of silt and soil sampling, geological mapping and an 8.2 line-kilometre ground electromagnetic survey on the area as the Helga claims. In 1978, a program of geological mapping and two diamond drill holes, totalling 628.0 metres, were completed on the Vine 29 claim. In 1979, a 47.8 line-kilometre ground electromagnetic survey was completed. In 1984, a soil sampling program was completed. In 1988, the area was prospected as the Puma claims. The following year, Placer Dome completed a program of geological mapping and rock, silt and soil sampling. In 1990, the area immediately east was prospected as the Cougar 4-6 claims.
In 1992, drilling intersected exhalative massive sulphides and a large hydrothermal alteration zone of the type associated with the Sullivan deposit. Sulphide mineralogy in a zone of strong mineralization consists of pyrrhotite, pyrite, galena and sphalerite and appears to be banded in places and oriented at a high angle to the core axis. Arsenopyrite and scheelite have also been identified in core. A 1 metre intersection of massive sulphides assayed 1.3 per cent zinc, 9.8 per cent lead and 100.09 grams per tonne silver (George Cross News Letter No. 222 (November 17, 1992)).
The drillhole was oriented northeast along a direction of fractures associated with surface mineralization to determine if these fractures represented seepage of mineral from depth. The collar of the hole was set up directly on the surface showing and drilled northeast (045 degrees), down slope and down-section into the Aldridge Formation. There are no structural features within the core to indicate the hole was collared in or drilled along a shear zone (George Cross News Letter No. 220 (November 16, 1992)).
In 1996 and 1997, Citation Resources Inc. drilled greater than 13,000 metres in 17 very deep holes without intersecting any significant mineralization. In 2006, Saint Eugene Mining completed 697 line-kilometres of airborne combined magnetic and electromagnetic surveys on the area. In 2013 and 2014, PJX Resources completed gravity surveys on the area as the West Basin property.
