The 100% owned Tanacross Project covers 45,900 hectares of prospective ground in the Yukon-Tanana Terrane, which hosts the Casino porphyry Cu-Au-Mo-Ag deposit and the Coffee & Pogo orogenic Au deposits. Widespread hydrothermal alteration and several notable occurrences of porphyry style mineralization have been recognized on the property including the advanced stage East Taurus porphyry Cu-Au-Mo-Ag system.
Location and Access
The Tanacross Project is located in eastern Alaska, 80 kilometers to the northeast of Tok, near the Yukon-Alaska border. The property can be accessed by fixed wing aircraft to one of three gravel airstrips located at the East Taurus, West Taurus and Bluff prospects or by a winter access road which connects to the Taylor Highway near the town of Tok. A 25-person semi-permanent camp is located next to the 600 meter airstrip at West Taurus.
Geology and Mineralisation
The regional geology of the Tanacross area is dominated by middle to upper Paleozoic metamorphic rocks of the Yukon-Tanana terrane which have been intruded by Mesozoic to Tertiary felsic to intermediate plutonic rocks. The project is located at the intersection between two major terrane-scale structures: the NW trending, arc-parallel Big Creek Fault and the NE trending, arc-perpendicular Sixtymile-Pika Fault.
Geology within the Tanacross Project includes a series of Late Cretaceous intrusive stocks, dykes and breccias emplaced into the metamorphic Lake George assemblage basement rock. Intrusive phases include granite, gabbro, pegmatite dykes, quartz-latite, monzonite, quartz-monzonite, quartz-monzonite porphyry, feldspar-porphyry, quartz- feldspar porphyry, intrusion breccia, granodiorite and diorite porphyry. The metamorphosed basement rocks intersected in drilling include orthogneiss, paragneiss, augen gneiss, schist, amphibolite and heterolithic gneiss breccia.
Historical exploration on the Tanacross Property has identified several target areas with known mineralisation including East Taurus, West Taurus, Bluff, East Denison, Pushbush and Big Creek. The more advanced prospects which have been the focus of historical drilling include East Taurus, West Taurus, and Bluff.
East Taurus has seen the most significant amount of historical drilling and hosts a well mineralised multi-phase porphyry Cu-Au-Mo-Ag system with a core of potassic alteration (k-feldspar-biotite-magnetite) and quartz stockwork surrounded and overprinted by later quartz-sericite-pyrite ± chlorite-illite alteration. The core zone of potassic alteration is elongated in an east-northeast to west-southwest direction, and Cu-Au-Mo-Ag mineralisation has been intersected by drilling over an 800m length, varying from 100 to 200m in width.
West Taurus encompasses a significant area of quartz-chlorite-sericite-pyrite-magnetite with local K-feldspar alteration containing quartz – molybdenite ± chalcopyrite stockwork veining hosted within intrusion breccias and quartz latite rocks. The system zones outward into widespread quartz-sericite-pyrite alteration.
The Bluff target contains a large alteration system characterised by overprinting zones of quartz-sericite-pyrite, chlorite-sericite, silicification, tourmaline, and rarely identified Kspar-biotite alteration. Intrusive rocks include a quartz-latite porphyry, feldspar porphyry, and tourmaline breccia pipes.
The paragenetic relationships and morphology between lithologies, style of mineralisation and alteration zonation on the Tanacross Project is typical of many calc-alkaline related porphyry copper-gold-molybdenum-silver systems. Age dating and lithological relationships suggest the intrusions, alteration and mineralisation forming the Taurus-Bluff mineralised centers spanned over approximately five million years from 67Ma to 73Ma. Significant Late Cretaceous calc-alkaline high level porphyry stocks occur elsewhere within the Yukon Tanana Terrane, including the Casino porphyry Cu-Mo-Au deposit (74.3 ± 0.5Ma), located along the Big Creek Fault system to the southeast in Yukon, Canada.
Copper mineralisation was first discovered in the area in 1970 by International Minerals and Chemicals Corp which led to the discovery of the Taurus Cu-Mo-Au-Ag porphyry system. The USGS conducted regional stream sediment sampling for the Tanacross quadrangle in the mid 1970’s, stimulating further exploration activity within the vicinity of the project area. Subsequent exploration programs focused on additional stream sediment and soil sampling, along with geologic mapping and prospecting, identifying several porphyry Cu-Mo and banded Pb-Zn-Ag-Au prospects. In general, follow-up was limited to shallow drilling on a number of these prospects, with the exception of the East Taurus system which has seen several drill campaigns since the initial discovery.
From 1971 to 2011 nine different companies drilled a total of 52 combined reverse circulation and diamond drill holes (8,019m) on the Tanacross property. The drill campaigns assayed for various elements including Cu, Mo, Au, Ag, Pb and Zn, however analyses prior to 1979 were not assayed for Au. These holes mainly focussed on porphyry Cu-Mo-Au style mineralisation at East and West Taurus with historical highlights including:
- 96DDH030: 174.96m at 0.31 % Cu, 0.10 g/t Au, 0.032 % Mo
- 96DDH032: 208.48m at 0.23 % Cu, 0.14 g/t Au, 0.032 % Mo
- 08DDH040: 232.56m at 0.31 % Cu, 0.25 g/t Au, 0.036% Mo
Despite these early campaigns, the extensive 45,000 hectare Tanacross Project remains largely under-explored and untested. More recent tectonic and metallogenic work completed by the Mineral Deposit Research Unit (MDRU) at the University of British Columbia as part of the Yukon-Alaska Metallogeny Project, as well as regional campaigns undertaken by the USGS have greatly added to the understanding of structural and temporal controls of various deposit types throughout the region.
Summary of exploration activities conducted by Kenorland Minerals
The Tanacross Project was acquired through physical staking in February, 2017 along with the purchase of claims covering two historically known porphyry copper (gold-molybdenum) occurrences, including East Taurus and West Taurus, in June, 2017.
In the summer of 2017 Kenorland carried out geologic mapping and soil sampling around the Taurus-Bluff area as well as a limited regional ridge and spur soil sampling program covering areas away from the known mineralised centers.
In 2018 Kenorland and Freeport-McMoRan (Freeport) entered an earn-in to joint venture agreement with Freeport funding exploration and Kenorland as operator. In the summer of 2018 additional ridge and spur soil sampling was carried out extending coverage over the entire 45,900 hectare property.
In summer of 2019 a 9,057 meter diamond drill program was completed targeting known porphyry mineralisation at the East Taurus, West Taurus, and Bluff prospects. In addition to drilling, a property-wide helicopter-borne ZTEM and magnetic survey was flown to identify geophysical expressions of buried porphyry or skarn systems located elsewhere on the property. The drill program expanded the known mineralised footprints within the East Taurus, West Taurus, and Bluff target areas with highlights including:
- 19ETD050: 285.00m at 0.23% Cu, 0.16 g/t Au, 0.036% Mo, 1.08 g/t Ag
- 19ETD051: 412.37m at 0.11% Cu, 0.12 g/t Au, 0.015% Mo, 1.17 g/t Ag
In March 2020, Freeport terminated the option agreement resulting in Kenorland maintaining 100% ownership of the Tanacross Project.
In 2021, the Company completed various surveys including detailed mapping, soil sampling, and geophysics. Detailed soil sampling and rock chip mapping was carried out over the East Taurus, West Taurus, South Taurus target areas, covering an area of approximately 25 square kilometers. An additional detailed soil sampling and mapping grid was completed over the Big Creek target area within the southern portion of the property. In total 1,474 samples were collected between the two grids. High-resolution drone magnetic surveys were carried out over the same areas covering East, West and South Taurus as well as Big Creek. In addition, a Titan™ high-powered IP, and magnetotelluric (MT) survey, was completed along a five kilometer survey line over the South Taurus target area