Eaglehead is an advanced exploration stage polymetallic porphyry copper project (16,492.6 ha) located in the Liard Mining District of British Columbia, approximately 50 kilometers (kms) east of Dease Lake in Tahltan territory. The project hosts two open-ended deposits, two areas of widespread mineralization and 176 additional copper showings.
The project is underlain by Quesnel terrane, Mesozoic island-arc assemblages comprising volcanic and sedimentary rocks and associated intrusions. The I-type, calc-alkalic Lower Jurassic (195 Ma) Eaglehead stock is the main intrusive underlying the Eaglehead project. The project is located close to the boundary between the Quesnel and the Cache Creek terranes and is underlain by a substantial portion of the Eaglehead stock. The Quesnel terrane hosts numberous copper deposits and mines including Highland Valley, Mt. Milligan, and Mount Polly in British Columbia.
Eaglehead is a multi-phase intrusive exhibiting several texturally and compositionally distinct intrusive facies are recognized in the Eaglehead Intrusive. Older marginal and equigranular mafic rocks of Quartz diroite composition have been intruded by younger, centrally located, inequigranular to porphyritic felsic intrusives of granodioritic composition.
Age dating (U/Pb zircon) of the Eaglehead Intrusive yielded a Lower Jurassic age for the Quartz diortie at 195.1+/-0.13 Ma and 194.8+/-0.1 Ma for the granodirite; comparable in age to other calc-alkalic copper porphyry systems in British Columbia. Age dating (Re-Os) of molybdenite mineralization yielded a 194.2+/-0.9 Ma date indicating emplacement of the porphyry copper-molybdenum-gold-silver mineralization occurred 500,000 to 700,000 years after crystalliztaion of the Eaglehead Intrusive.
In April 2021, Copper Fox purchased a 100% working interest in the Eaglehead project for CA$1.2 million, $200,000 was paid upon signing the Agreement with the remaining $1 million to be paid in three installments on each anniversary date following the closing. The Agreement also grants a 0.5% net smelter return (NSR) royalty over the Property, half of which can be purchased for $1 million at any time up until the second anniversary of commercial production. Certain mineral tenures covering the Property are subject to various NSR royalties, of which from 50% to 75% can be purchased for amounts ranging from $1 to $2 million.
- 8km long porphyry footprint
- 126 diamond drillholes (36,605m) of which 120 drillholes contain significant intervals of copper mineralization with low but significant concentrations of molybdenum-gold-silver
- Three stages of copper mineralization
- Mineralization hosted in granodioritic, Quartz diorite, late-stage Quartz Feldspar porphyry dikes and mafic volcanics of Kutcho Formation
- Preliminary metallurgical testwork produced a clean, bulk copper-molybdenite concentrate with good metal recoveries
- Sr/Y and V/Sc ratios indicate that certain phases of the Eaglehead intrusive are prospective for large copper (+- gold) deposits
- Untested 10km long semi-continuous copper-molybdenum soil geochemical anomaly and coincident 6km long open-ended positive chargeability anomaly
The field mapping, geological modelling and age dating of major lithologies completed in 2021 and 2022 has redefined the geology of the southwest portion of the Eaglehead Intrusive. Quartz diorite is the oldest unit within the Eaglehead Intrusive. The Quartz porphyry is granodiorite in composition and the most abundant unit within the Eaglehead Intrusive. The youngest unit is granodiorite in composition located between the Quartz porphyry and the Quartz diorite. Late-stage aplite, quartz feldspar porphyry and mafic dikes have also been identified.
The mineralization and alteration intersected in drillholes and in outcrop represents the upper levels of a paragenetically, homogeneous, large porphyry system. The porphyry mineralization chargeability signatures, mineralized outcrops and Cu-Mo geochemical anomalies are located within a specific fault-controlled block measuring approximately 8km long by 3km wide. The strong spatial association of the mineralized zones to the regional scale Thibert Fault represents a structural setting like that at the Red Chris deposit.
Historical drilling resulted in a 500m long interval between the Bornite and East mineralized zones that has never been tested by diamond drilling. The chargeability signature in this interval suggests continuity of the mineralization and that the Bornite and East zones could be the same mineralized zone.
The 2022 program initially included a 2,500m drilling program to test the 500m interval between the Bornite and East zones. The delay in the receipt of the Mines Act Permit (received November 2022) and onset of winter weather conditions delayed the drill program until 2023. Field activities conducted in 2022 included re-logging and sampling of historical drillholes, water sampling, outcrop mapping and updating of the geological model for the mineralized zones. Results of these activities are outlined below.
The geological modelling of the mineralized zones included reviewing the lithologies, alteration and mineralization in 34 historical drillholes within the Camp, Pass, Bornite and East zones. This work identified previously unsampled intervals of copper mineralization (chalcopyrite +/- bornite) in 11 drillholes. The sampling was completed to establish the limits of the mineralized envelope in each drillhole. The weighted average grades of mineralized intervals yielding greater that 0.05% Cu are set out below:
|Zone||DDH||From (m)||To (m)||Interval (m)||Cu (%)||Mo (%)||Au (g/t)||Ag (g/t)|
Notes: a) metal concentrations of less than 0.01 g/t Au and 5.0 ppm Mo listed as tr. b) cut-off for mineralized intervals 0.05% Cu. c) capping of higher-grade sample results were not employed. d) weighted average interval includes up to 12m core length of material below the Cu cut-off. e) intervals do not represent true thickness.
Of the 11 holes sampled, five holes returned intervals of >0.05% copper mineralization which either extends previously known mineralized intervals or represents new mineralized intervals in these drillholes.
Sampling (32 samples from 16 sites) was completed in early July and in mid-September and analyzed for components outlined in the BC Drinking Water Quality and Aesthetic Guidelines. Negligible changes in ionic concentrations were observed in the analytical results.
Eight copper showings were located during the 2022 mapping program. Two samples, which exhibited remnant secondary copper (malachite) in the center of quartz veinlets, indicating a high degree of leaching of the primary copper mineralization, were submitted for analysis. The first sample collected 770m northeast of camp yielded 0.11% Cu, trace Mo, <5 ppb Au, and 0.165 g/t Ag and the second sample 900m west of camp returned 0.66% Cu, trace Mo, trace g/t Au and 0.434 g/t Ag.
The 2022 surface mapping program combined with the subsurface modelling of the lithologies within the Bornite and East mineralized zones resulted in updating the distribution of the lithologies within the southwest portion of the Eaglehead Intrusive. Quartz diorite is the oldest unit withing the Eaglehead Intrusive. The Quartz porphyry is granodiorite in composition and the most abundant unit within the Eaglehead Intrusive. The youngest unit is granodiorite in composition located between the Quartz porphyry and the Quartz diorite. Late-stage aplite, quartz feldspar porphyry and mafic dikes also occur.
Historical exploration includes 126 diamond drill holes (36,605m), preliminary metallurgical testwork, airborne and ground geophysical surveys, soil and stream sediment geochemical surveys and limited prospecting and mapping. Between 2014 and 2022, re-logging of 94 drillholes and re-analysis of pulp samples and additional core samples from 99 drillholes (22,697m) were completed. Historical drilling intersected broad intervals of porphyry style mineralization, alteration and lithologies. Selected mineralized intervals (at 0.10% Cu cut-off) from the two deposits (Bornite & East) and mineralized areas (Camp & Pass) are listed below.
|Zone||DDH||TD (m)||Dip||From (m)||To (m)||Interval (m)||Cu (%)||Mo (%)||Au (g/t)||Ag (g/t)|
Notes: tr=element present but in amounts less than 30 parts per million; n/a=not analyzed due at time of drilling, core lost.
Chalcopyrite with subordinate bornite (with low concentrations of gold-silver) are the primary copper minerals hosted in sheet like fractures, quartz stockwork, disseminated grains, blebs and in late-stage magmatic hydrothermal breccia and with gypsum veinlets.
In addition to the mineralization intersected in the drilling, 176 copper showings have been located in an area approximately 3,000m by 2,000m north of the Pass-Camp-West zones. Select sampling from these showings returned the following metal values: copper 0.06% to 6.90%, molybdenum 1 to 488 parts per million (‘ppm’), gold 3 to 5,285 parts per billion and silver 0.02 to 49.20 ppm. These copper showings are hosted in moderate to intense potassic, pervasive phyllic (sericitic) and late stage propylitic altered rocks.
The historical drill data for the project are set out in the table below. The drill holes on the Pass, Camp, Far East and West zones were completed in the 1970’s and 1980’s and essentially tested the near surface mineralization. These drill holes were selectively sampled and over time, the cores from many of these drill holes have been lost due to improper storage procedures, resulting in intervals of the core that could not be re-loggged/sampled.
|Zone||DDH Drilled||Cu Grades (%)||Total Meters||Mineral Assemblage|
Py=pyrite, Cpy=chalcopyrite, Bn=bornite, Mo=molybdenite, Cu=copper.
Preliminary Metallurgical Testwork
Two phases of lock-cycle and variability testwork on mineralized samples from the East, Bornite and Pass zones yielded a clean, bulk cleaner copper-molybdenum concentrate that assayed 29.6% Cu, 2.72% Mo, 28.2 g/t Au and 175.9 g/t Ag with metal recoveries of 89.9% Cu, 71.1% Mo, 78.6% Au and 78.1% Ag to concentrate. The Bond Work Indices that ranged from 16.9 to 20.6 kWh/t (average 18.6 kWh/t) and Bond Abrasion Index ranged from 0.211g to 0.554g (average 0.381g).