The Davis-Keays or Eagle developed copper prospect is situated around the south fork (known as Caribou Creek) of Yedhe Creek, 7 kilometres west-northwest of Yedhe Mountain in the mountainous Muskwa Ranges of the Northern Rocky Mountains, approximately 161 kilometres west of Fort Nelson (Assessment Reports 1128, 2388; Geology, Exploration and Mining in British Columbia 1971). An airstrip was constructed in the late 1960s, along with a road connecting the camp with the Alaska Highway to the north, at Mile 442. The Davis-Keays deposit is one of the most important concentrations of vein-hosted copper mineralization in the region, ranking with the Magnum mine or Churchill Copper deposit (094K 003) 5 kilometres to the southeast. Most of the work carried out on the property was done between 1967 and 1972; there was some renewed interest in 1987. This occurrence covers several veins and showings over an area of about 12 square kilometres, roughly centred on the main Eagle vein.
The occurrence is in a region known as the Muskwa Anticlinorium, a major north-northwest trending structure characterized by moderate folding and thrust faulting. The structure consists of Middle Proterozoic (Helikian) rocks of the Muskwa Assemblage, as well as Paleozoic rocks (Geological Survey of Canada Map 1343A; Geological Society of America, Geology of North America, Volume G-2, pages 111, 639). All belong to Ancestral North America (Geological Survey of Canada Map 1713A). Northeast to northwest trending diabase dikes of Proterozoic age are common in the region.
The showing occurs in the Aida Formation of the Muskwa Assemblage, which comprises shale or slate, dolomitic and calcareous shale, dolostone and minor limestone (Geological Survey of Canada Memoir 373). The sequence is of considerable thickness, and in the Eagle occurrence area it has been crudely divided into three units (Geology, Exploration and Mining in British Columbia 1971). From bottom to top, the units comprise a) grey-weathering limestone and interbedded calcareous shale, b) buff to orange-weathering dolomite and interbedded dolomitic shale, and c) dark grey-weathering calcareous shale with minor interbedded impure limestone. Bedding in this area generally strikes west-northwest and dips gently to moderately southwest. Numerous diabase dikes, ranging from a few metres to more than 100 metres wide, cut the sedimentary rocks. All dikes dip steeply or vertically and most strike northeast. The dikes produce a minimal amount of contact metamorphism in the surrounding sedimentary rock.
The strata are folded about axes that plunge gently southeast. All folds are asymmetric, with steep northeast and gentle southwest limbs, and have an axial planar slaty cleavage that strikes northwest and dips steeply southwest. Though regionally widespread, most folds are concentrated in a northeast-trending belt approximately 2500 metres wide that crosses the Eagle property. This belt, though not containing very many diabase dikes, contains most of the quartz-carbonate veins known in this area. Nearly all these veins trend northeast parallel to the belt and dip vertically or steeply northwest, nearly perpendicular to the axes of the southeast plunging folds. Also, within this belt are large northeast trending, subvertical fracture zones and buff to orange-weathering dolomitic and ankeritic alteration in the otherwise grey-weathering limestone and calcareous shale. Some of these zones contain cupriferous quartz-carbonate veins.
Of all the mineralized quartz-carbonate veins on the Eagle property, the Eagle or Eagle-Mike vein system is the largest and probably the only commercially viable, and has undergone the most development. The particular structure hosting this system has been traced horizontally for approximately 1375 metres, and has been explored underground over a vertical height of about 500 metres by a system of four levels, three sublevels, and a number of connecting raises. The vein occurs in a strong fracture zone that lies almost perpendicular to the axes of closely clustered, southeast-plunging folds within a tightly folded sequence of shale, limestone and dolostone. The zone strikes approximately 036 degrees and dips steeply northwest. Dips are variable, averaging about 80 degrees in the upper part of the vein and approximately vertical in the lower levels. Local reversals of dip have been observed in the northern section of the lower workings. Average vein width is 1.2 metres but considerable variation exists, mostly in the range of 0.3 to 2.7 metres, giving the vein a complex lenticular form rather than a uniform tabular shape (Assessment Report 2388). Despite abundant post-mineralization faults, the vein is essentially continuous.
Faults within this zone are commonly parallel to both walls of the vein but are rare and of limited extent across the plane of the vein. Only two faults with significant lateral offsets (3 to 6 metres) are known. Rock alteration along or near the northeast trending fracture planes, which locally are occupied by veins, commonly include development of graphite and iron-rich dolomite and ankerite. Adjacent to the vein, the wallrocks have undergone various degrees of silicification and decalcification. Contacts between vein and altered wallrock are sharp.
Sulphides occur in both massive and disseminated form. Chalcopyrite is the most abundant (80 to 90 per cent of total sulphides), with pyrite and negligible covellite. Chalcopyrite is commonly present as massive patches of large anhedral grains. Less commonly, it forms a fine, fracture-filling in the earlier pyrite. Pyrite forms small irregular masses or individual grains distributed unevenly throughout the vein. Covellite occurs sporadically throughout the underground workings in very minor amounts, principally as a thin rim around some chalcopyrite grains and along thin irregular fractures within pyrite grains. Oxidation at and near the surface, and along some fracture zones, has produced abundant limonite, malachite and azurite locally. The majority of the vein, however, is essentially unoxidized. Gangue is principally quartz with lesser but variable amounts of carbonate in the form of calcite or siderite.
Indicated (probable) reserves at the Eagle property are 128,808 tonnes grading 2.92 per cent copper; semi-proven reserves are 1,119,089 tonnes grading 3.43 per cent copper (Statement of Material Facts July 4, 1972 - Davis-Keays Mining Company Ltd., Chapman, Wood and Griswold, June 1971).
The Keays vein and Keays North vein showings lie 2.75 and 2 kilometres, respectively, southwest of the southernmost exposures of the Eagle-Mike vein and are roughly on strike with it. The Keays North vein is 0.75 to 1 metre wide and very poorly mineralized or barren on the surface. The Keays vein yielded assays averaging 3.57 per cent copper across 2.4 metres over a length of 67 metres (Geology, Exploration and Mining in British Columbia 1971). Drilling in 1969 suggests that the Keays vein does not connect with the Keays North vein, and its width and grade do not continue with depth (Assessment Report 2388).
The William vein is 1 kilometre north of the Keays vein. Chalcopyrite is reported in quartz-carbonate vein zones.
The Harris vein is 2 kilometres south of the Eagle-Mike vein (Assessment Report 1128; Property File - Prospectus, Mango Resources Limited, 1988). Chalcopyrite-bearing quartz veins up to 2.6 metres thick yielded assays averaging 3.77 per cent copper across 2.1 metres over a 150 metre strike length, but subsequently, a limited amount of underground work (130 metres) and considerable diamond drilling indicated that the vein quickly wanes at depth and to the north (Geology, Mining and Exploration in British Columbia 1971). The Creek vein, 200 metres north of the Harris vein, does not appear to be of good grade or width on the surface.
The Pink vein, 200 metres east-northeast of the Harris vein, is very irregular and of limited horizontal continuity, and appears to be cut by a northeast trending diabase dike. This vein is characterized by the common occurrence of erythrite; cobalt assays up to 0.5 per cent (Assessment Report 1128) and 0.61 per cent (Property File - Prospectus, Mango Resources Limited, 1988) have been reported. A chip sample taken from the best section of this vein assayed 3.76 per cent copper and a trace of silver across 76 centimetres (Geology, Exploration and Mining in British Columbia 1971).
The View showing, halfway between the Eagle-Mike and Harris-Pink vein systems, comprises two hand trenches 90 metres apart exposing massive chalcopyrite in quartz-calcite veins. A grab sample from the lower trench assayed 5.75 per cent copper over a width of 1.5 metres (Property File - Adamson, R.S.(1967): Summary Report).
The Ridge vein is 350 metres southeast of the View showing and 900 metres northeast of the Harris vein. It is largely covered by scree, but was exposed by hand trenching, revealing semi-massive chalcopyrite mineralization which assayed 1.35 per cent copper over 1.2 metres (Property File - Adamson, R.S.(1967): Summary Report).
The Sheep vein, located approximately 1.3 kilometres northwest of the Eagle vein, is based only on a train of mineralized boulders in the extensive scree (Assessment Report 2388).
The Northeast vein comprises four small veins in interbedded buff-weathering dolostone and shale. They lie two kilometres northeast of, and approximately on strike with the Eagle vein structure. The veins are between 30 and 60 centimetres wide and are of limited horizontal extent. Two chip samples taken across some of the best mineralized material assayed 6.54 per cent copper and 41.1 grams per tonne silver across 27 centimetres (Geology, Exploration and Mining in British Columbia 1971).
The Don vein is 2.75 kilometres northwest of the Sheep vein and is also reported to contain chalcopyrite in quartz-carbonate veins.
The Oscar and Bob veins are quite different from the copper-bearing veins, despite being situated right among them (Assessment Report 1128). The Oscar vein is approximately 650 metres southwest of the Eagle-Mike vein. The width and extent are unknown because of extensive scree cover, but appears to be modest. As indicated by float, the vein trends southeast, along the regional cleavage and transverse to the trend of all other veins. The mineralization consists of massive and semi-massive galena, with a trace of bornite locally, a grab sample of which assayed 84.21 per cent lead, 0.05 per cent copper, 0.44 per cent zinc and 236.5 grams per tonne silver (Geology, Exploration and Mining in British Columbia 1971; Assessment Report 1128). The Bob vein is 600 metres north of the Oscar vein and contains massive galena mineralization. One 4-metre chip sample assayed 26.75 per cent lead and 182 grams per tonne silver (Assessment Report 1128).
During the 1940s, copper was discovered in the area while the Alaska Highway was being built. Exploration activity took place during the 1950s and early 1960s, but was most active during the late 1960s and early 1970s. The two main deposits identified in the area were the Davis-Keays (Eagle vein), discovered in August, 1967, by prospectors Harris Davis and Robert Keays of Fort Nelson, and the Churchill Copper (Magnum vein) deposit (094K 003). Between 1968 and 1971, underground development was carried out on the Eagle and Harris veins (Davis-Keays). During this three year period, over 2.9 kilometres of underground work was completed including over 1920 metres of drifting and sublevels on the mineralized vein, 596 metres of cross-cutting and 335 metres of raising. Other vein-style occurrences on the property were prospected, trenched, and the Harris, Keays, and Keays North veins received a limited amount of drilling. In 1970, MacDonald Consultants Ltd. completed a Feasibility Study, which was complemented a year later by an Evaluation Report done by Chapman, Wood & Griswold Ltd. Metallurgical tests at Lakefield Research, Peterborough, Ontario, indicated satisfactory 95 per cent recovery from copper concentrate grading 28 per cent using conventional crushing, grinding and floatation. Production was planned but never commenced, due to adverse economic and political conditions in the mid-1970s. At an undetermined date because no reports are available, Kam Kotia Mines carried out 148 metres of underground development on the Harris vein, including approximately 30 metres of access and 118 metres of drifting along the vein. Quartz-carbonate veining with chalcopyrite mineralization was observed throughout the 670 metre-long tunnel.
In 1979-80, L.B. Halferdahl completed a helicopter-supported geochemical reconnaissance survey in part of the Tuchodi area and a total of 681 soil samples were collected in an attempt to find base metal anomalies in areas covered by overburden.
In 1996, Reliance Geological Services, for Seguro Projects Inc., carried out a work program on the Key Property consisting of geochemical rock sampling. Eighteen rock chip samples were collected and sent to International Plasma Laboratory Ltd. of Vancouver, British Columbia. Five samples collected from the Harris vein assayed greater than 2 per cent copper with a high result of 7.73 per cent. The Pink vein yielded values up to 1.73 per cent copper. The Creek vein is weakly mineralized, and appears to lack the width needed to host significant copper mineralization.
In 1998 and 1999, assessment work consisting of Landsat TM (optical) and JERS-1(radar) image studies and structural interpretation, was carried out by Crest Geological Consultants. It was concluded that post-mineralization northwest-trending faults may have truncated several veins. If that structural interpretation is correct, there may be several areas in the vicinity of the Eagle, Magnum, and Neil (094K 040) veins that contain more vein structures with accompanying copper mineralization.
In 2002, Senator Minerals Inc. and Seguro Projects Inc. carried out a work program designed to locate and sample the Pink vein and its extensions to confirm the presence of cobalt mineralization, to trace the length of the vein, and to test the theory that cobalt mineralization in area veins may be related to elevation. Lower priority objectives included the location and tracing of the Harris vein and an investigation of possibly accessible underground workings on that vein outside of the main underground development associated with the Eagle vein. Two select and ten rock chip samples were collected from the Pink vein and its presumed extensions. One select sample was taken from the entrance to an adit, at 1722 metres elevation, which accesses the Harris vein. The main objective of the 2002 program was realized by the identification of a correlation between cobalt mineralization and elevation, with all significant cobalt values coming from elevations of less than 1828 metres. Copper exploration potential of the Pink vein extension was also confirmed, with 12 samples taken along the 500-metre sampled length of the vein yielding copper values ranging from 114 ppm to 4.53 per cent. The secondary objective of identifying underground workings on the Harris vein was also realized.
In late June 2005, Aries Resource Corp. plans to perform airborne magnetic and electromagnetic surveys over its Trident project properties. The airborne geophysical surveys are designed to test the extent of mineralization on the various properties. Along with this helicopter-supported program, the company plans to reclaim access roads and open underground workings prior to drilling known mineralization in order to bring historical reserves to current resource categories. Aries controls 34 separate properties, covering an area of over 10,000 hectares. This land package contains most of the known copper occurrences in the Churchill belt, which is well known for hosting economic vein-style deposits of copper, gold and silver. The project area contains several advanced deposits, as well as showings and prospects on at least 14 other properties. The two primary developed properties are the Magnum (094K 003) and Davis-Keays (094K 012, this description) mines.
Between May and June, 2006, McPhar Geosurveys Ltd. carried out a heliborne magnetic survey for Bradford Mineral Explorations Ltd. over parts of their Trident property. Between August and October, 2006, Aeroquest Limited carried out a heliborne magnetic and electromagnetic survey for Bradford Mineral Explorations Ltd. over parts of their Trident property.
In 2009, Seguro Projects Inc. carried out work on the mineral claims comprising the Key Property. An underground sampling program of the Harris vein was completed where rock samples were taken across the entire width of the of the Harris vein, along the 118-metre exposed length of the vein, at approximately 10-metre intervals. Twenty-one chip samples were taken yielding copper values ranging from 0.004 to 6.16 per cent. Four samples assayed between 0.5 and 0.99 per cent copper, and five samples yielded greater than 1 per cent copper.
During the 2015 field season, prospecting was carried out by C. Warren along the Bonanza Creek drainage.
During late August 2016, R.M. Beck collected ten samples on the Key Property. The samples were taken from quartz-dominant float along Harris and Caribou creeks.