The stratigraphic top of the Lower Jurassic Mount Dilworth formation (Hazelton Group) comprises intermediate lapilli fragmental with clasts and matrix containing carbonate and up to 40 per cent disseminated and massive volcanogenic pyrite. This pyritic horizon which is approximately 30 metres thick and at least 100 metres long, occurs in contact with overlying black pyritic mudstone of the Lower Jurassic Salmon River formation (Hazelton Group). Mineralized angular talus boulders located along the trace of this contact comprise up to 30 centimetre thick quartz lenses with 40 per cent disseminated and layered pyrite. A rock sample of this material contained 478 parts per billion gold, 9.7 parts per million silver with elevated arsenic and antimony concentrations (Assessment Report 22501). Although these values are low, they are considered to represent evidence of gold and silver bearing massive sulphide mineralization at this important stratigraphic horizon.
In addition, 350 metres north of the Slide zone, a rock sample of a pyrite-quartz lamination from the basal, pyritic black mudstone unit of the Salmon River formation also contained elevated silver, arsenic and antimony concentrations.
Work History
Reconnaissance soil sampling in 1988 identified a southwesterly trending multi-element, arsenic-antimony-lead-copper-gold-silver anomaly in the northwest corner of the Polo 5 claim (as reported in Assessment Report 22591).
It was reported that in 1989 Aerodat Ltd conducted a 200 line kilometre combined helicopter airborne magnetic, electromagnetic and VLF survey of the Polo claims for American Fibre Corporation (as reported in Assessment Report 22591).
In 1990, prospecting near the centre of the Polo 7 claim located hydrothermally altered, pyritic and silicified tuffs which yielded 1.38 grams per tonne gold and 0.2 per cent arsenic from a grab sample; near the north end of the Polo 5 claim, a silt sample contained an anomalously high of 0.27 gram per tonne gold and 0.03 per cent arsenic (as reported in Assessment Report 22591).
In 1991, reconnaissance geological mapping, prospecting and geochemical sampling were performed on portions of the Polo 7 and 8 claims by American Fibre Corporation and Heritage Petroleum Inc. Rock grab samples from the Club zone assayed up to 3.81 grams per tonne gold and 86.06 grams per tonne silver; soil and rock samples anomalous in gold, arsenic, silver and antimony were obtained from the Bluff zone (as reported in Assessment Report 22591).
The 1992 exploration program on the Polo 7, 8 and Fog 1 to 6 claims included approximately 39.5 kilometers of line cutting and grid preparation, 1:5000 scale geological mapping, 41.6 kilometres of magnetometer and very low frequency (VLF) electromagnetic surveying, and the collection of 1,518 soil samples and 22 rock samples.
In 2004, an airborne EM-magnetic survey was flown late in the field season as part of a larger program encompassing all the Heritage Explorations Ltd claims in the Eskay area. By 2005, Heritage had acquired mineral rights over an extensive area (53,283 hectares) in the Eskay Creek region of north-western BC. In 2005, seven conductive anomalies were selected for drilling from the 2004 results, based on conductive response, stratigraphic position, local geochemical anomalism and depth. Drill holes PO-05-01 and PO-05-02 were collared at UTM coordinate 409547 East, 6271491 North to test a flat lying EM anomaly on the west side of the Unuk River (Assessment Report 28338). Pyrite occurs as disseminations and minor graded beds in the upper regions of both holes; and massive pyrite clasts as debris flows in argillaceous sediments are prevalent at the interface with amygdaloidal flows. These clastic zones have high levels of mercury associated with them.
In 2020, Eskay Mining Corp. completed a program of prospecting, rock sampling, ground and airborne geophysical surveys and 4335 metres of diamond drilling in 20 holes on the area as part of the Sib-Corey-North Mitchell property. The geophysical surveys consisted of a 911.7 line-kilometre airborne electromagnetic survey, a 55.85 line-kilometre induced polarization survey and a 43.19 line-kilometre magnetotelluric survey. Drilling was performed on the TV (MINFILE 104B 385) and Jeff (MINFILE 104B 525) occurrences.
