Finlay’s 100%-owned ATTY property covers 33.93 km2 of sub-alpine terrain in the southern Toodoggone region. The Toodoggone is a northwest-trending belt of Triassic to Jurassic arc terranes that hosts numerous significant porphyry Cu-Au ± Ag and associated epithermal Au-Ag deposits (Fig. 1). Several epithermal-style Ag ± Au ± Cu ± base-metal veins are exposed on the Property, and geochemical and geophysical work have outlined at least two promising porphyry targets. The ATTY Property adjoins Centerra Gold’s Kemess property, which hosts the past-producing Kemess South porphyry Cu-Au-Mo-Ag deposit, the Kemess Underground deposit (positive Feasibility study 2016), and the Kemess East deposit (positive PEA 2017). ATTY covers several high-potential and under-explored porphyry and epithermal exploration targets.
ATTY is underlain predominantly by two volcanic sequences of the Upper Triassic Takla Group : 1) pyroxene-phyric mafic flows interbedded with subordinate mafic ash tuffs and volcanic wackes; and 2) a unit of massive mafic lapilli fragmental volcanics. Lying unconformably on top of Takla units are four sub-units of the Lower Jurassic Hazelton Group, which are composed of, from bottom to top, 1) a mafic volcaniclastic and epiclastic unit with course fragments and clasts of Takla Group units, 2) mafic tuffs, 3) intermediate volcaniclastics and epiclastics, and 4) hematitic mafic crystal tuffs.
The volcanic units at ATTY are intruded by granodiorite, monzonite, and syenite of the Lower Jurassic Black Lake Suite. These units are relatively weakly altered medium-grained intrusions containing quartz, plagioclase and hornblende. Takla volcanic and sedimentary units are consistently upright and young toward the northeast, however Jurassic units appear relatively flat lying, occurring as roof pendants on local mountain peaks in the central ATTY area.
The northwest-trending Saunders Fault transects the property, and several parallel structures are observed elsewhere. The dominant northwest-trending structural grain is truncated by mesoscale northeast-trending structures and several smaller scale east-west trending faults that are interpreted as forming horst-and-graben style block faulting. While they have not been explicitly mapped, it is considered likely that late (Eocene) shallowly dipping north-vergent thrusts are present.
The ATTY property hosts seven (7) known mineral occurrences, consisting mainly of sub-metre to m-scale veins of quartz ± carbonate ± pyrite - galena-sphalerite-chalcopyrite-barite that can be traced along-strike for tens to hundreds of metres. The veins and associated mineralization appear to be controlled by both NW-trending and E-W trending structures and are interpreted based on regional correlations to be Lower Jurassic in age. Proximity to the Kemess deposits, widespread epithermal mineralization, and various geophysical and geochemical anomalies suggest the potential for Cu-Au porphyry mineralization on the property.
The Wrich target area lies in the NW corner of the ATTY / ATG property, where 2021 soil sampling identified a Au-Mo anomaly in the vicinity of the Wrich 1 showing, an Au-Ag epithermal system that yielded up to 0.54 g/t Au; 99.7 g/t Ag in vuggy quartz vein grab samples. Immediately west of Wrich, Amarc’s Takla SW target yields Cu and Au-in-soil anomalies.
At the Attycelley showing, at least two ENE-striking dm- to metre-scale quartz-galena-sphalerite-chalcopyrite-barite veins can be traced for up to 470 m along strike. Several samples have yielded ore-grade Ag, Cu, and Pb. A 1990 grab sample yielded 240.6 g/t Ag, 0.22 g/t Au, 0.385% Cu, and 9.1% Pb. Grab samples collected in 2021 from the Attycelley vein system (n=13) assayed an average of 73 ppb Au, 32.0 g/t Ag, 0.18% Cu, 1.68% Pb, and 1.30% Zn. The vein system is open along-strike, and a continuous soil geochemical anomaly suggests strong potential for its continuation.
The Attycelley showing is a set of large quartz-galena-sphalerite-chalcopyrite-barite veins that can be traced for up to 500 m along strike. Several samples have yielded ore-grade Ag, Cu, Pb and Zn.
Attycelley Zone: Zinc Rock, Soil and Trench Results
In 2022 a Trench yielded 32.4 g/t Ag, 0.34 % Cu, 1.07 % Pb, 2.98 % Zn and 0.04 g/t Au over 11m including a 1m sample yielding 198 g/t Ag, 1.62 % Cu, 8.23 % Pb, 0.88 % Zn, and 0.18 g/t Au.
ATTY 2022 Trench # 2 (7-8 metres)
ATTY 2022 Trench # 2 (10-11 metres)
2022 Attycelley Sample F927487: 87.0 g/t Ag, 0.78% Cu, 2.62% Pb, 2.17% Zn and 0.32 g/t Au
Grab samples collected in 2021 from the Attycelley vein system (n=13) assayed an average of 73 ppb Au, 32.0 g/t Ag, 0.18 % Cu, 1.68 % Pb, and 1.30 % Zn. The vein system is open along-strike, and a continuous soil geochemical anomaly suggests strong potential for its continuation.
2021 Attycelley Sample C114872: 50.3 g/t Ag, 0.16% Cu, 8.66% Pb, 1.76% Zn, 0.06 g/t Au
2021 Attycelley Sample C114877: 55.8 g/t Ag, 0.46% Cu, 4.55% Pb, 10.50% Zn and 0.03 g/t Au
The KEM showing consists of a <4 metre-wide, moderately south-dipping, quartz-carbonate-chalcopyrite-pyrite-hematite-magnetite vein that can be traced for >150 m along-strike. A 1982 chip sample of this vein yielded 29.95 g/t Ag, 0.442 g/t Au, 4.24 % Cu, 0.8 % Pb, and 0.2 % Zn.
KEM Zone: Copper Rock and Soil Results
In 2021, workers identified a 0.5 – 1.0 m zone of massive magnetite with pods of massive sulphide and K-feldspar-actinolite selvedge, which they traced for over 200 m along-strike. Samples from this structure assayed up to 1.01 % Cu and 8.76 g/t Ag.
In 2022, field work expanded the extent of the known mineralization and further supports the potential for a porphyry system at the KEM Target. Alteration mapping north of historic drilling showed a gradational increase in the intensity of propylitic alteration northward, with exposures of weak potassic alteration assemblages in the far north. Multiphase quartz-carbonate-chalcopyrite-malachite-pyrite veins range in thickness from 5 cm – 2.0 m and trend subparallel to topography for > 1 kilometre. Samples yielded up to 0.61 g/t Au, 49.5 g/t Ag, and 1.10 % Cu. Average assay values for the rock samples were 0.11 g/t Au, 0.29 % Cu, and 14.9 g/t Ag.
The visually prominent, orange-brown weathered ATTY Gossan surrounding the KEM showing has been hypothesized to reflect the effects of a buried and mineralized intrusion, analogous to the large (~800 x 3,300 m) well-developed east-west trending gossanous zone that overlies the nearby Kemess North deposit. The ATTY Gossan and KEM target areas may represent the continuation of the Kemess North Trend. The presence of magnetite both within the main KEM vein as well as in veinlets with pyrite ± chalcopyrite in depth at drill core has been interpreted as a possible indicator of porphyry mineralization at depth.
2022 KEM Sample #F927464
2022 KEM Sample #F927466
2022 KEM Sample #F927467
K2022 KEM Sample #F927478
Airborne radiometric and magnetic surveys can provide useful exploration tools for porphyry deposits, which generally exhibit characteristic alteration aureoles. Typically, a potassic core (K-feldspar-biotite-magnetite-quartz-pyrite) is surrounded by a phyllic (quartz-sericite-pyrite) shell within regional propylitic (chlorite-epidote-quartz ± magnetite ± pyrite) alteration. Potassium enrichment in the core of a deposit may result in an anomaly in radiometric imagery (K, Th/K). Similarly, hydrothermal magnetite in the potassic zone may result in a magnetic high, generally surrounded by relatively low magnetic field intensities in the shell which exhibits magnetite-destructive phyllic alteration.
The Geoscience BC 2004 Toodoggone airborne survey revealed several, predominantly NW-trending, magnetic high anomalies on the ATTY property. The most intense magnetic high anomaly underlies the Kem target, consistent with abundant observed magnetite.
Ground-based induced polarization (IP) surveys are a common and effective method of identifying sulphide mineralization, intrusive bodies, and major structures at depth. Several ground-based IP campaigns on the ATTY property have successfully identified blind intrusions and associated pyrite.
In 2007, a Quantec Titan 24 IP survey was completed across the southern portion of the ATTY claims in the vicinity of the Kem prospect, which directly neighbors the Kemess Underground and East deposits. A similar deep-sensing IP program east of Kemess North that same year resulted in the exploration drilling at the Kemess East deposit. The 2007 survey identified a significant chargeability anomaly (>20 mV/V).
In 2018, Serengeti Resources optioned the ATTY property and completed ~20 line-km of ground-based IP in 7 lines over the Kem area. Three of the 2018 lines identified the 2007 Titan anomaly, expanding it to an area measuring ~600 x 600 m.
Further IP surveys by Serengeti in 2019 identified two additional targets - all three geophysical targets consist of coincident chargeability and resistivity anomalies in areas with favourable geological and geochemical conditions.
In 2019, three IP lines along the Attycelley River valley identified a large (~1600 m x 800 m), strong (up to 56 mV/V) sub-horizontal chargeability high with a coincident magnetic signature. Below the eastern portion of the chargeability anomaly lies a resistive feature (up to 2500 Ohm-m) with a co-located increase in magnetic intensity which was hypothesized to represent an intrusive plug. Drilling of the chargeability in two drillholes (AT-19-09 & -10) intersected pyritized andesite and monzonitic plugs with sporadic anomalous Cu and Au.
Three IP lines over the FogMess area in 2019 defined a chargeability anomaly (up to 28 mV/V) and associated resistivity feature (up to 2500 Ohm-m) below elevated Au and Ag surface sampling results from 2018. The area is defined by intense silica alteration and flooding with local, structurally hosted pyrite-chalcopyrite-Cu-oxide mineralization. Work by Dr. Jim Oliver in 2018 suggests that this surface mineralization may be related to a porphyry system at depth. A single hole (AT-19-11) was drilled in the to test the IP signature, intersecting intermittent epithermal-style veining with modest mineralization.
In 2004, Finlay completed 1,653 m of diamond drilling in seven holes to test coincident geochemical and geophysical anomalies at the ATTY Gossan (Kem) zone. In 2018, Serengeti Resources Ltd. optioned the property, re-logged and sampled the 2004 core, and completed geological mapping and IP programs to target a drill program the following year. The first phase of the 2019 IP campaign identified both the large Valley Target along the Attycelley Creek and an IP anomaly in the FogMess area in a zone highlighted by Dr. Jim Oliver during the 2018 mapping program (“Boundary Target”). In 2019, Serengeti Resources drill-tested the ATTY Gossan, Valley Target, and FogMess area with 2,318 m in 6 drill holes.
The final drill hole of the 2004 campaign at Kem (AT-04-07) intersected sheeted pyrite veins and veinlets transitioning to sheeted magnetite-chalcopyrite veinlets with K-feldspar halos towards the EOH at 304 m. Infill sampling during the 2018 program combined with prior results indicates a 36.11 m interval near the end of this hole assaying 0.10% Cu and 0.12 g/t Au. AT-19-08 was drilled ~385 m southeast of AT-04-07 to test the area down-dip of observed mineralization, as well as the 2007 Titan IP target and the block immediately adjacent to the NNW-trending fault that truncates the Kemess East deposit. Results were disappointing, though did indicate a broadly anomalous Au (e.g., 0.14 g/t Au over 87.70 m) in potassically altered andesite.
Drill holes AT-19-09 and -10 were drilled ~1135 m apart along the Attycelley Creek valley, targeting an intense chargeability anomaly identified in Phase 1 of the 2019 IP program. Hole AT-19-09 intersected significant pyrite in Takla Group rocks but did not intersect any intrusive bodies, whereas AT-19-10 intersected a coarse-grained monzonite for most of the length of the hole.
In AT-19-09, pyrite (1 – >5%) occurs as veinlets and disseminated in mafic pyroclastics and augite- and feldspar-phyric volcanics of the Takla Group, and corresponds well to the observed chargeability high. Volcanic wall rock exhibits pervasive moderate propylitic and phyllic alteration. Alteration minerals include pervasive epidote, magnetite, and pyrite, with intermittent sericite and K-feldspar. Pyrite content remained consistently above 1 – 5 % with trace chalcopyrite until 427 m. Mineralization was restricted to 0.20 % Cu and 0.4 g/t Ag over 3.7 m of quartz-sericite-pyrite altered andesite with blebby chalcopyrite hosted in pyrite veinlets and finely disseminated in the groundmass below a dm-scale shear from 214.3 –218.0 m.
AT-19-10, collared 1135 m southwest of AT-19-09, collared into monzonite with moderate phyllic alteration and pyrite veinlets, which it remained in until 59.0 m, where a silica- K-feldspar breccia over several metres gives way to laminated ash of the Takla Group with weak propylitic and potassic (silica-K-feldspar-magnetite-chlorite-biotite) alteration. From 403.0 – 496.0 m (EOH) medium- to coarse-grained salmon-coloured quartz monzonite exhibits intermittent zones of brittle shear and calcite-zeolite vein stockwork. Calcite-zeolite veining is dominant throughout AT-19-10, comprising ~1 – 5 %; lesser vein phases include quartz-carbonate, quartz-pyrite ± chalcopyrite and pyrite ± chalcopyrite veinlets, which generally occur as < 1% of the core. Weak Au-Cu-Ag mineralization was intersected in several m- to dm-scale intervals in AT-19-10 (Table 1). Broad Au anomalies are an encouraging sign of porphyry potential.
The presence of quartz-pyrite ± chalcopyrite and pyrite-chalcopyrite veining in AT-19-10 indicate potential for porphyry-style mineralization. The 2019 IP and drilling were the first work done on the Valley Target and the results warrant further work.
Drillhole AT-19-11 drilled below an area of silica-flooded pyrite-chalcopyrite-Cu-oxide bearing zone and strong chargeability anomaly identified by 2018 mapping (Jim Oliver) and Phase I IP surveys near the Fog-Mess Minfile occurrences. The hole intersected several intervals with elevated Au-Ag-Pb-Zn, predominantly in epithermal-style veins and vein breccias cutting propylitically altered Takla Group volcanics.
From 166.3 – 174.5 m, a steeply WNW-dipping hydrothermal breccia zone (grading 0.01 % Cu, 0.07 g/t Au, and 4.9 g/t Ag over 8.2 m) separates augite-phyric andesite from a mafic lapilli to block agglomerate below which continues to EOH. From 231.7 – 232.7 m, a brecciated agglomerate yielded 0.39 g/t Au, 26.81 g/t Ag, 0.01% Cu, 0.06 % Pb, and 0.36 % Zn over 1.0 m.
No intrusive rocks are intersected in AT-19-11 but several m-scale sections of hydrothermal breccia host barite and quartz ± carbonate ± pyrite ± sphalerite ± galena ± chalcopyrite veining. Structural measurements from AT-19-11 (n=77) reveal a dominantly northwest-trending structural grain, with most structures dipping steeply to the southwest.