The FS (Chase Silica) occurrence is located on Niskonlith Creek, approximately 10 kilometres west- south west of the community of Chase.
The area is underlain by schist, amphibolite and greenstone of the Hadrynian and/or Paleozoic Silver Creek Formation (Mount Ida Group). These have been intruded by Cretaceous granodioritic intrusive rocks to the south and east. Sediments and volcanics of the Upper Triassic Nicola Group outcrop to the west.
Locally, two exposures of thick, milky white quartz veins are separated by approximately 400 metres in a north-south direction. The quartz veining appears to be hosted in a fault zone near the contact between the Silver Creek Formation rocks and a Cretaceous granite. Drilling, in 1981, is reported to have established continuity between the two outcrops.
At the southern outcrop, the quartz vein strikes northwest-southeast at approximately 330 degrees and dips steeply from 60 to 70 degrees to the north east. The vein varies from 1 to 20 metres in width and has been traced for 600 metres. Surrounding rocks are mainly felsic schists and amphibolites. The quartz is milky white and coarse- grained, with occasional well-formed crystals reaching 10 to 20 centimetres in length. Minor impurities that are present throughout the width of the vein include seams of fuchsite and reddish, rust-stained patches. A zone of impure vein quartz, up to 7.5 metres wide, is transitional to extensive quartz stockwork in altered country rock on either side of the main vein. The pit walls contain variable amounts of quartz stockwork veining. The hanging wall of the main vein is mineralized with galena, sphalerite, chalcopyrite, pyrite, tetrahedrite, pyrrhotite and magnetite with hematite and limonite alteration. The sulphides occur as blebs, patches and veinlets over a width of 25 to 75 centimetres and have been traced along strike for greater than 30 metres in the quarry. Scheelite and possibly tungstenite mineralization are also reported.
In 1981, diamond drilling (hole S-80-5) yielded values up to 520.2 grams per tonne silver, 1.49 per cent lead and 1.60 per cent zinc over 1.8 metres, while a 10.2- metre section averaged 116.3 grams per tonne silver, 0.164 per cent zinc and 0.156 per cent lead (Assessment Report 9529).
In 1996, three channel samples (S-2, S-4, S-6) averaged 377.2 grams per tonne silver, 1.7 per cent lead and 0.08 per cent zinc over 3.51 metres, while a grab sample, taken along strike 360 metres away, assayed 80.0 grams per tonne silver (Assessment Report 25115). Diamond drilling, performed the same year, intersected a quartz zone hosting 5 to 15 per cent sulphides over 35.25 metres. A 3.0- metre section, near the end of the zone, assayed 9.1 grams per tonne silver (Assessment Report 25115).
In 2015, a grab samples (M-4) across 1.5 metres of a mineralized quartz vein assayed 758 grams per tonne silver and 3.10 per cent lead (Assessment Report 36150).
At the northern outcrop (granite dome outcrop), a quartz vein striking 040 degrees with a steep dip occurs within leucocratic granitic rocks. The vein is 20 metres wide. The quartz is coarse- grained, massive and milky white. Minor yellow and orange rust staining occurs on fractures and rare grains of sulphides are present in the quartz. Quartz stockwork veining occurs throughout the granite. In 1969, a random chip sample assayed 99.74 per cent silicon dioxide, 0.064 per cent total iron, trace aluminum oxide and nil calcium oxide (Open File 1987-15, page 29).
Several shipments were made from a quarry on the southern outcrop to silicon and silicon carbide plants in Oregon but no production figures are available. In 1980 and 1981, Interior Stone and Marble completed 14 diamond drill holes, totalling 1242.8 metres. In 1982, the north-south– elongated quarry measured 110 by 35 metres. In 1996, AFF Automated Fast Foods completed a single diamond drill hole, totalling 217.7 metres. In 2014 and 2015, the area was prospected as the Mick claims.
