Old workings of the Gold Hill prospect occur on the east flank of a north-trending ridge separating Whistle and Henri creeks, 5.0 kilometres west-southwest of Hedley.
The area is underlain by Upper Triassic Nicola Group volcaniclastics and sediments which are separated into the younger Whistle Creek Formation and the older Hedley Formation. These rocks are intruded by Early Jurassic hornblende porphyritic diorites of the Hedley Intrusions. A second plutonic suite of the Cahill Creek pluton also intrudes these rocks and consists of massive, biotite or hornblende granodiorites which are Middle Jurassic in age.
Mineralization is primarily hosted in interbedded tuffaceous siltstone, argillite and andesite ash tuff of the Whistle Creek Formation. This sequence is intruded by dykes and sills of fine-grained and coarse hornblende porphyritic diorite of the Hedley Intrusions. The dykes and sills locally carry disseminated pyrite and arsenopyrite. The sedimentary beds generally strike 180 to 185 degrees, dip vertically and are locally tightly folded.
Trenching and stripping has exposed a breccia zone over a 30 by 25 metre area comprised of sedimentary fragments in a calcite-quartz matrix. Fine-grained sediments, containing conformable bands of calcite 1 to 5 centimetres wide, appear to underlie the breccia zone. Locally, the carbonate vein margins are densely packed with elongate, interlocking sharply angular brecciated fragments of hornfelsed and skarn-altered wallrock up to 15 centimetres long. These clasts are rimmed by two generations of carbonate growth, an early, brown- coloured possibly ankeritic carbonate and a later phase of white crystalline calcite. An adit, 40 metres below surface exposures, intersected similar calcite-quartz breccia and calcite-banded wallrock over a distance of 20 metres. The breccia, and to a lesser degree the banded rocks, are mineralized with coarse masses of pyrite, small blebs of black sphalerite, and minor arsenopyrite, chalcopyrite and galena in surface and underground exposures. A grab sample of bedded, fine-grained sediment interlayered with calcite, containing pyrite and coarse sphalerite, assayed 8.85 grams per tonne gold and 7.9 grams per tonne silver (Assessment Report 10882, page 28, sample 48584).
To the southeast, a northwest-striking shear zone has been traced by two short adits over a distance of 20 metres to within 20 metres of the brecciated sediments. The zone contains coarse masses of silvery pyrite (arsenopyrite?) in leached and vuggy quartz. A sample of massive pyrite with quartz assayed 4.32 grams per tonne gold and 16 grams per tonne silver (Assessment Report 10882, page 27, sample 48570).
This prospect was first explored in the mid-1930's, by Hedley Gold Hill Mining Company Ltd., by several short adits and shafts, one long adit and a number of trenches and opencuts. Between 1982 and 1989 Philex Gold and Energy Corporation has carried out soil and geophysical surveys, geological mapping and sampling over the old workings.