The NE zone area is underlain by Early Jurassic andesitic and dacitic flows and tuffs of the Toodogone Formation (Hazelton group) which overlie altered intrusive rock. The intrusion is composed of syenite to quartz monzonite and granodiorite to quartz diorite of the Early Jurassic Black Lake Intrusive Suite.
Several proximal to distal alteration zones are recognized which show some similarities to those associated with many porphyry copper. Drill holes PN04-13 to PN04-16 on the NE zone in 2004 demonstrated that the high IP chargeability anomalies reflect barren pyritic units that could be either pyritic haloes or pyritic centers to a porphyry system. However, surface copper showings are rare, the copper soil geochemical data is weak and only minor amounts of copper mineralization were intersected in holes PN-04 13 to 16. By contrast, a gold-in-soil anomaly is present on the southern side of the ridge, about 200 to 300 metres south and southwest of drill hole PN04-16.
Hole PN04-16 intersected A 3.0 metre interval containing 0.20 per cent zinc (Assessment Report 27602). Sporadic and narrow zones of copper-lead and zinc were reported are present in holes 15 and 16. Gold content with the exception of one spot high in hole PN04-14 (0.438 gram per tonne) is usually less than 0.1 gram per tonne (Assessment Report 27602). Rock intersected in the holes is reported to be mainly andesitic flows and monzonite. Drillhole PN04-13 yielded 2.27 per cent zinc, 0.480 per cent copper and 0.033 per cent tungsten over 1.80 metres (Assessment Report 27602).
Despite the extensive alteration, copper mineralization was only seen at three localities 1) UTM 622340E, 6358896N: minor malachite along a northeast striking fault that cuts monzonites structurally underlying the altered volcanic cap-rocks,
2) UTM 623086E, 6359160N: malachite and minor chalcopyrite hosted by a sheared monzonite dike,
3) UTM 623054N, 6359216N: a road cut exposes extremely clay-silica plus/minus sericite-altered volcanics with a glassy green mineral (crysocolla?).
Another zone of chalcopyrite mineralization, referred to as the Xenos occurrence, is reported approximately 1.7 kilometres to the northeast. A long electromagnetic conductor is reported associated with the occurrence.
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. conducted detailed stream sediment and contour soil sampling with exploration culminating in hand trenching an epithermal gold-silver prospect (now called Atlas West). A rock sample (SC-31-80-13) of volcanic rock with quartz and pyrite veining, taken approximately 1.5 kilometres to the east from an area hosting minor chalcopyrite, yielded 0.07 gram per tonne gold, 0.021 per cent copper and 0.19 per cent lead (Assessment Report 9001).
In 1985 and 1986, Rhyolite Resources Inc. completed programs of geological mapping, trenching and geochemical (heavy mineral, rock and soil) sampling on the Adrian, Argus, Ian, Otto and Paul claims. Also at this time, Kelly-Kerr Energy Corp. completed a program of geological mapping and geochemical (rock and soil) sampling on the area immediately east as the Debra Lynn claim. Also in 1986, the Toodoggone Syndicate completed an airborne geophysical survey on the area.
In early 1987, Rhyolite Resources Inc commissioned Western Geophysical Aero Data Ltd. to process and interpret magnetometer and VLF-electromagnetometer data gathered across the Argus claim group. The data was gathered as part of a regional program completed in early spring of 1986. Five areas of interest were outlined. Later in 1987 Rhyolite conducted a regional program consisting of geologic mapping, multipole induced polarization and geochemical sampling. In 1990, Rhyolite conducted a soil geochemical sampling program to extend the coverage of an existing survey grid and to explore a new area within the claim group.
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 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). Lloyd geophysics conducted a ground magnetometer and induced polarization (IP) and resistivity survey over a copper-gold porphyry prospect, on the Pil North claim group (Assessment Report 27055B). Geophysical surveying in 2002, on more closely spaced lines, has confirmed the continuity and size of both the Northeast and West Central high chargeability zones.
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). Examination and reporting on the Central-Milky zones were reported. It was reported in 2003 that geochemically, as well as geophysically the Milky Creek and Central zones merge, giving a combined target of about 4000 metres length. A grab sample (RB03PN27) of monzonite with quartz veinlets, taken approximately 1 kilometre to the northeast, assayed 0.191 gram per tonne gold (Assessment Report 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 focussed 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. Two rock samples (GRR05-06 and -07) altered diorite with disseminated pyrite yielded 0.113 and 0.200 gram per tonne gold (Assessment Report 28083).
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 2007, Finlay Minerals Ltd continued exploration of its Pil property, concentrating on the Atlas East epithermal gold-silver target. Soil and rock geochemistry, and an IP program, provided context to a 7 hole, 2410 metres drilling program, the results of which have not yet been released.
In 2015, Finlay Minerals completed a program of geological mapping and geochemical (rock and soil) sampling on the Pil claims.