Petrographic analysis of sample W16R-30 in 2016 describes the rock as a hypabyssal (shallow depth) feldspar ± biotite porphyry of about monzonite composition. It is cut by strongly developed stockwork of chalcopyrite-minor bornite-pyrite veinlets associated with quartz, alkali feldspar suggesting this is alkaline porphyry copper-type mineralization in a low iron/high copper system. Interestingly the petrographic descriptions of Copper Cliff rocks suggest that magnetite is absent or altered to hematite.
These results are very encouraging as they describe a new and previously unrecognized type of copper mineralization occurring in high level intrusive and related (co-magmatic?) volcanic rocks.
The presence of intrusive rocks at Pillar East is considered very significant. In the Toodoggone region, porphyry copper mineralization is spatially and genetically associated with intrusive rocks, their co-magmatic (related) volcanics and adjacent volcanics such as the Takla Group (i.e. Kemess). At Pillar East, a small body of Early Jurassic age Black Lake diorite is mapped by the BC Geological Survey near the northern portion of the epithermal Au-Ag zone. In addition, a breccia dike found in 2006 approximately 1.5 km west-northwesterly in the Atlas East Zone contains fragments of granitic rock and copper mineralized volcanics. This could indicate that geologically prospective intrusive rocks underlie the Pillar and Atlas Zones.
Previous multisensor surveys over similar BC porphyry type copper deposits such as Afton and Mt. Milligan have yielded positive results. Radiometric (Potassium, Thorium/Potassium ratio) and magnetic (total field and calculated vertical gradient) maps are particularly useful in identifying potassic alteration and magnetite enrichment/depletion zones associated with these porphyry deposits and in mapping bedrock lithologies and structures.
The Pillar East mineralized zones when plotted on the airborne survey maps coincide with distinct geophysical features. On the magnetic calculated vertical gradient map, the mineralized zones occur proximal to a magnetic low centered within a prominent, nearly circular two-kilometer diameter magnetic high. This may reflect magnetite destruction resulting from 1) hydrothermal effects of the epithermal Au-Ag zone and 2) alteration of the hypabyssal intrusive and adjacent volcanics associated with the Copper Cliff Zone.
Epithermal Gold-Silver Quartz Vein System -
The 2016 exploration objectives were to further trace and sample epithermal style precious metal mineralization first identified in 2006-07 by highly anomalous gold and silver (Au, Ag) in soil, silt and rocks 1.5 km east of the Company’s Atlas East epithermal Au-Ag zone. Some of the most anomalous soil samples from the 2007 work assayed >1.0g/t Au with one containing 6.75g/t Au. Panning of rusty, crumbly surface material from a small outcrop revealed very fine-grained, angular gold suggesting a local bedrock source. Similar angular gold was also panned from creeks several hundred meters to the north-northeast. In 2015 the rusty outcrop was tested with a three meter, steeply angled drill hole. All but one sample (wall rock) returned strongly anomalous gold and silver (results reported in April 29, 2016 news release). Angular talus fragments of rusty, epithermal style quartz collected 25 meters north of the 6.75g/t Au soil returned 8.3g/t Au and 39.7g/t Ag. The 2015 work concluded that this mineralization represents a volcanic hosted, north-northeast trending and steeply dipping epithermal structure nearly 500 meters long and of indeterminate width.
Work in 2016 tested many of the strongest gold-in-soil and rock sample anomalies from the previous programs. In virtually every case anomalous gold-in-soil was confirmed by evidence of quartz veining, stockwork or quartz breccias. Close spaced soil samples collected across the gold anomalies returned from background to 2.88 g/t Au. Of the ten soil samples containing >0.1g/t Au, nine yielded from 1.1 to 50.3g/t Ag with one soil sample assaying 232g/t Ag. Twelve of the sixteen rock samples collected during the follow-up work returned anomalous Au and Ag ranging from background to 6.57g/t Au and background to 69.7g/t Ag respectively. Many of the most anomalous soil and rock samples also contain significant amounts of lead (Pb) and zinc (Zn) with some rock samples occasionally grading over 0.5% combined Pb-Zn.
Significant Rock Samples from Pillar East Epithermal Au-Ag Zone
|Sample||Sample Type||Length (m)||Au (g/t)||Ag (g/t)||Pb (ppm)||Zn (ppm)|
|W16R-05||Bedrock chip of rusty zone||0.75||1.57||16.3||1,403||485|
|W16R-07||Composite chips of angular float||0.50||6.57||13.1||1,531||1,727|
|W16R-09||Chip sample of rusty zone||2.50||1.07||13.0||467||798|
|W16R-10||Composite rock chips across talus slope||15.0||1.25||69.7||2,724||4,449|
To date the geological and geochemical evidence and data indicate that the Pillar East Epithermal Au-Ag Zone is approximately 800 meters long and of unknown width. It is open along strike with the possible strike extensions especially to the south obscured by talus.
Given the positive exploration results, the Company anticipates continued work and plans more extensive exploration including further prospecting, sampling, mapping, Induced Polarization (IP) geophysical surveys and ASTER satellite imagery of these new mineralized zones. The results of this work will help define future drill targets.
Warner Gruenwald, P.Geo. and Vice President, Exploration for Finlay Minerals Ltd. is the Qualified Person as defined by National Instrument 43-101 and he supervised the exploration work and has prepared the above material. Sample analysis was conducted by Bureau Veritas (formerly Acme Labs.) in Vancouver, BC. Seven rock samples reporting >4,000 ppm (0.4% Cu) were re-analyzed by Bureau Veritas using method MA401, a multi-acid, ore grade classical wet assay method that utilizes a four acid digestion followed by an Atomic Absorption Finish.