The Atlas West quartz-chalcedony breccia zone is underlain by andesitic volcanics belonging to the Early Jurassic Toodoggone Formation.
The Atlas West prospect is underlain by crystal lapilli tuff, breccia and derived sediments contained within a fault bound panel of the Saunders Member, Toodoggone Formation. The volcanics are characterized by plagioclase and minor potassic feldspar phenocrysts. These are intruded by porphyry dikes. Fracture controlled propylitic and argillic alteration are common. These are surrounded by volcanics of the Metsantan Member, Toodoggone Formation.
The Atlas West prospect consists of a quartz-chalcedony-amethyst breccia zone, hosted in feldspar porphyry andesite. The groundmass is moderately to intensely altered to chlorite and clay minerals throughout the whole breccia zone. Feldspar phenocrysts are generally altered to sericite and other secondary minerals, possibly a bright orange zeolite. Two trenches have revealed three or more generations of veining and brecciation. Vein materials include black chalcedony, milky white or grey chalcedony, clear to amethystine cockscomb quartz and rare pyrite. The veins are commonly laminated. Wallrock in the breccia zone may or may not be silicified. In Trench 2, the host rock is strongly clay altered and contains specularite. Vein orientations are generally not well defined. The dominant trend appears to be 125 to 135 degrees, parallel to a fault zone.
Significant assay results were obtained from Trench 2 where there was greater than 50 per cent vein material. Grades averaged 91.54 grams per tonne silver over 7 metres and 0.82 gram per tonne over 5 metres (Assessment Report 10326). The best 1-metre interval assay was 147.1 grams per tonne silver and 0.99 gram per tonne gold (Assessment Report 10326).
In 1991, two grab samples (AH5 and AH6) assayed 0.705 and 0.685 gram per tonne gold with 4.0 and 75.6 grams per tonne silver, respectively (Assessment Report 22248).
In 1993, samples (SP-12 to -15) of epithermal style-veining from former trenches yielded values up to 0.850 gram per tonne gold and 74.2 grams per tonne silver (Assessment Report 23313).
In 2003, a chip sample (RB03PN019) from a former trench assayed 1.07 grams per tonne gold and 122.8 grams per tonne silver over 3.0 metres (Assessment Report 27310).
In 2004, grab sampling of the former trenches yielded up to 1.59 grams per tonne gold and 131 grams per tonne silver (Sample TD64; Assessment Report 27602).
In 2004, Finlay Minerals mapped and sampled the Atlas West trenches and examined the geology and some gossanous outcrops in the surrounding area. This reconnaissance work included the collection of rock, soil and silt samples at both the Atlas West and Atlas East, which are approximately 700 metres apart. Grab samples from the Atlas West trenches gave maximum assay values of 1.58 grams per tonne gold and 140 grams per tonne silver, while gossanous float taken down-slope from the Atlas East gossan contained up to 3.2 grams per tonne gold and 80 grams per tonne silver (Assessment Report 27602).
In 2006, two holes were drilled in the Atlas West zone to test the epithermal mineralization exposed by historic (Serem) and more recent trenching. Both holes intersected Toodoggone (Metsantan) volcanics over their entire length but did not intersect the type of silicification, veining or brecciation seen in the overlying trenches. Amethyst was noted at 72.8 to 78.0 metres and in a silicified, veined and brecciated zone at 95.4 metres. All core samples however contain less than 0.5 gram per tonne gold and 5.0 grams per tonne silver (Assessment Report 28984).
Other zones of mineralization have been identified over approximately 400-metre strike length to the east-northeast along ‘SEREM’ ridge and comprise float and outcrop exposures of quartz-carbonate veins with variable amounts of pyrite, galena, chalcocite and malachite and a narrow, 0.25-metre wide, dike hosting chalcopyrite with ‘exotic’ copper-secondary minerals. The dike cuts well-bedded Pillar Member volcanic rocks and strikes 290 degrees with a 57-degree dip north.
In 2004, samples from the quartz-carbonate veins yielded up to 0.528 per cent copper, 0.244 gram per tonne gold and 8.6 grams per tonne silver, and a sample from the mineralized dike yielded 0.952 per cent copper and 22.3 grams per tonne silver (Assessment Report 27602).
In 2006, numerous angular fragments of often containing native copper were traced over an area of at least 100 by 150 metres with a composite sample (Tan 001) of blue-green epithermal (?) quartz being collected yielding 0.477 gram per tonne gold, 11.2 grams per tonne silver and 0.116 per cent copper (Assessment Report 28984). This float was traced up to but does not source from the breccia dikes identified in 2004. A 25-centimetre chip sample (Tan 003) across the breccia dike assayed 16.8 grams per tonne silver and 0.83 per cent copper (Assessment Report 28984).
Work History
In 1967, Cordilleran Engineering drilled two holes in the northwest part of the Pil property.
In 1969, Cominco explored a copper porphyry target on the south part of the Pil property.
In 1980 and 1981, SEREM Ltd. completed programs of prospecting, geological mapping, trenching and geochemical (rock, silt and soil) sampling on the area as the Atlas and Hercules claims. In 1985, SEREM Ltd. completed a further program of prospecting, geological mapping and a ground electromagnetic survey on the Atlas and Hercules claims.
In 1986, the Toodoggone Syndicate completed a 75 line-kilometre airborne geophysical survey on the area as the Daniel, Anna and Michel claims.
In 1991, six rock samples (all grabs) were collected from the Atlas and Hercules claims on behalf of Cheni Gold.
During 1992 through 1998, Electrum Resources Corp acquired the Pil claims and began a long methodical period of stream sediment, soil sampling, prospecting, rock sampling, Landsat imaging, and limited geophysical (VLF and magnetics) work (Assessment Reports 22750, 23313, 24356, 25054, 25282, 25811, 26104, 26383).
The Pil property of Electrum and Finlay changed in outline and contained at various times (and most recently (2014)): 094E 007 (Spartan), 094E 029 (Theban), 094E 083 (Arg), 094E 089 (Sun), 094E 147 (Pillar), 094E 200 (Reef), 094E 201 (Paul), 094E 202 (Ian), 094E 209 (Bishop), 094E 214 (GWP), 094E 213 (Atlas), 094E 215 (Michel), 094E 216 (Brook) and 094E 217 (Lar).
In 1999, Finlay Minerals purchased the property and conducted a major exploration effort including IP and magnetic surveys, soil/rock sampling and detailed geological mapping.
In 2000, rock sampling and hand trenching on the Pil South area.
In 2001, work focused on Pil North area with the completion of 8.3 kilometres of induced polarization (IP) and magnetic surveys, soil and rock sampling, and geological mapping.
In 2002, Finlay Minerals continued exploration efforts on Pil North (Assessment Report 27055) with the completion of 13.1 kilometres of induced polarization and magnetic geophysical surveys soil and rock sampling, trenching and geological mapping. Late in 2002 a lead-zinc silica-barite occurrence (WG Zone) was explored by hand and blast trenching. Prospecting in the area led to the discovery of quartz float containing 4.93 grams per tonne gold (Assessment Report 27055).
In 2003 Finlay Minerals completed a helicopter supported drill program consisting of four NQ holes totalling 707 metres on the Pil South property. Drilling targets were geophysical and geochemical anomalies. Results were inconclusive and did not fully explain the geochemical and geophysical anomalous zones. A total of 16.6 km of IP and soil sampling were completed along eight newly cut lines on the Pil North property. Prospecting, mapping and hand trenching were completed on the Pil North property. Gold bearing float discovered at the WG Zone in late 2002 was traced easterly for 300 metres. Additional quartz float containing visible gold and grading up to 16.8 grams per tonne was discovered nearly one kilometre east (WG-Gold Zone) (Assessment Report 27055, 27310).
In 2004, Finlay Minerals constructed a 7.5 kilometre access road, a fully serviced camp and 13.9 kilometres of drill access (exploration) trails. A reconnaissance diamond drilling program of 26 holes totalling 6,168 metres focused on five zones referred to as the Northeast, WG Zones, Northwest (NW), Milky Creek and Central Zones. Exploration targets were: (1) copper-gold porphyry deposits and (2) epithermal gold-silver deposits. Geological mapping and sampling were conducted over much of the property. Prospecting late in the season resulted in the discovery of boulders grading up to 3.22 grams per tonne gold and 80.6 grams per tonne silver near a large gossanous zone 800 metres east of the Serem trenches (Assessment Report 27602). This new area is referred to as the Atlas East Zone.
In 2005, Finlay Minerals constructed 5 kilometres of drill access roads on the NW Zone and established 10 kilometre of grid along which prospecting, soil and rock sampling were completed. Geophysical surveys (Magnetometer, VLF-EM) were completed along new and historic grid lines from the Silver Ridge Zone to the NW Zone. Geological mapping was completed on the NW, Silver Ridge, NE, WG Upper and Atlas East zones. Diamond drilling consisted of 12 holes totalling 3,090 metres were completed on the NW, Silver Ridge, and Atlas East zones. Ten drill sites and 3.3 km of roads from 2004 were reclaimed. Fill-in soil sampling was conducted on the existing grid from the Silver Ridge zone to the NW zone. Stream sampling follow-up of historic anomalies was completed. Detailed soil and rock sampling completed on the Atlas East zone identified numerous float and bedrock occurrences of epithermal gold and silver mineralization.
In 2006, Finlay Minerals constructed access road to Atlas East and West zones. Grid based soil, magnetic and VLF-EM surveys over a portion of the Atlas zones along with geological mapping and prospecting. Fourteen diamond drill holes (1945 metres) completed with twelve drilled on the Atlas and two on NW zones.
In 2015, Finlay Minerals completed a program of geological mapping and geochemical (rock and soil) sampling on the Pil claims.
