The Macex occurrence is located on the south side of Little Cedar River about 45 kilometres northwest of Terrace.
Upper Jurassic to Cretaceous black carbonaceous argillites and greywackes of the Bowser Lake Group are intruded by porphyritic quartz monzonite of probable Eocene age. Granodiorite of the Creatceous to Tertiary Coast Plutonic Complex lies to the west. The sediments trend north-northeast to north-northwest with moderate to steep west dips. They are locally graphitic and are weakly to moderately altered to biotite hornfels near the intrusive rocks. The plug-like and dike-like intrusions of quartz monzonite are strung out in a north-northeast direction.
Locally, two zones of mineralization, referred to as the Macex/LCR and Stilleto zones, have been identified.
The Macex/LCR zone contains abundant quartz veins occur over an area of at least 1500 by 1000 metres with prominent 104 degree trends and steep dips. Sulphides are present in about 20 per cent of the veins. Molybdenite and chalcopyrite occur in a 250-metre zone of quartz veins within bleached and sheared argillite and siltstone.
Silicification occurs along many of the joint planes and is associated with the sulphide mineralization. Pyrite is the most common with minor chalcopyrite occurring as disseminations in the altered host rock and within the quartz veining. Molybdenite and possibly ferrimolybdite, occur in the quartz veins or in quartz-chlorite lenses where they form disseminations of 1 to 2-millimetre flakes. Pyrrhotite and magnetite are present as minor constituents in the altered host rock.
Three 2004 drill holes were collared from one site and penetrated the quartz-veined sedimentary rocks but did not intersect the intrusion. Previous work and the magnetic data show the stock is located further east. The 2004 drilling found that the stockwork consists of steeply dipping, anastomizing, light grey to white, quartz-carbonate veins that are millimetre to centimetre-scale in thickness; average vein densities are 3-5 per metre and have a maximum true thickness of 15 centimetres. Mineralization within the stockwork occurs as pyrite, chalcopyrite, molybdenum, pyrrhotite, minor magnetite and very rare galena and is associated with quartz-carbonate veins and brittle or brittle-ductile shear zones; shear zones contain up to 10 per cent sulphides by volume. Pyrite is most common; it is fine grained, disseminated, averages 1-2 per cent where present in veins, shears, and hostrock. Disseminated, fine grained chalcopyrite is present from trace to 2 per cent by volume in both early (massive) and late (multistage/sheared) veins and shears. Very fine grained molybdenite is common as slicks and occurs along vein/wallrock or vein/vein interfaces.
The Stilleto zone is located a short distance south east and up slope of the LCR zone and is comprised of disseminated to semi-massive pyrrhotite-pyrite-chalcopyrite+/-molybdenite mineralization in silicified lithic arenite meta-sediments.
Work History
In 1969, the property was originally staked by Rio Tinto; there was no mention as to what the reason for the original staking was. Initial work by Rio Tinto involved an induced polarization (IP) ground geophysical survey with a grid spacing of 400 metres.
In 1979, the property was re-staked as the L.C. claims by Moly Syndicate of Smithers and work by Moly Syndicate involved general geologic mapping and a geochemical survey consisting of an 800 by 1100 metres, 285 sample soil grid. The property was then optioned to AMAX of Canada Ltd. in 1980. Work carried out consisted of local and regional geologic mapping and a geochemical survey totalling 191 soil samples and 101 rock chip samples. Grades were reported to average 0.02 per cent molybdenite and 0.06 per cent copper (Assessment Report 8446).
In 2004, an extensive exploration program was conducted by Eagle Plains Resources Ltd. and included a 545.9 line-kilometre VTEM geophysical survey conducted in March, plus a later geochemical survey totalling 707 soil samples, 110 silt samples and 110 rock samples. A 3-hole diamond drill program (483 metres) was drilled as well. Geologic mapping identified the potential for a high-level epithermal system overlying the copper-molybdenum porphyry system. It also resulted in the discovery of the Shae copper-molybdenum porphyry/copper-replacement showing (103I 229). The airborne geophysical survey delineated intrusive bodies whose contacts often are associated with mineralization. The soil geochemical sampling program was the most useful tool in the project. The Elsiar soil geochemical sample grid outlined a prominent copper-molybdenum anomaly over an 800 by 800 metres area which is open to the north and east. The three exploration holes successfully tested the subsurface extent of the mineralized quartz-carbonate stockwork at the LCR showing. Drilling yielded intercepts of up to 0.112 per cent copper over 28.5 metres, including 1.17 per cent copper over 1.6 metres in hole LC04001 (Sharp, R.J. (2008-01-22): 2008 Exploration And Geological Report for the Elsiar Cu-Mo Porphyry Property; Kenwood, S. (2011-01-07): 2010 Exploration and Geological Report for the Elsiar Cu-Mo Porphyry Property).
The 2005 Eagle Plains Resources exploration program consisted of three main components: reconnaissance geochemical and prospecting work to the south and east of the main focus area; detailed geologic mapping and infill geochemistry within the main focus area; and diamond drilling (20 holes totalling 2556 metres) of major targets defined during the 2004 and 2005 field work seasons. A grab sample from the Stilleto zone is reported to have assayed 0.47 per cent copper, while drilling yielded intercepts including 0.115 per cent molybdenum, 1.04 per cent copper, 35 grams per tonne silver and 0.35 gram per tonne gold over 1.0 metre in hole LC05007 or LC05008 located to the north east of the LCR zone, 0.19 per cent copper, 0.013 per cent molybdenum and 0.79 gram per tonne gold over 3.4 metres in hole LC05004 located east of the LCR zone and 0.038 per cent copper over 181 metres, including up to 1 per cent copper and 0.5 gram per tonne gold over 1 metre in hole LC0511 (Sharp, R.J. (2008-01-22): 2008 Exploration And Geological Report for the Elsiar Cu-Mo Porphyry Property).
The 2008 exploration by Eagle Plains Resources on the Elsiar property was carried out in two phases. The first phase of exploration was a geochemical survey (soil and silt sampling) between June 30 and July 21, and the second phase, from September 8 to September 14, consisted of geological mapping, and additional geochemical sampling of soils and stream sediments. Field work consisted of detailed geological mapping, following up known geochemical anomalies, stream sediment and contour soil geochemical sampling. TerraLogic Exploration Inc. conducted the program on behalf of Sandstorm Resources.
The 2010 exploration by Eagle Plains Resources was to follow up geochemical anomalies in float rock, stream-silt and soil samples determined during previous 2005-2008 field programs. Areas proximal to these anomalies and new areas of interest with insufficient previous sampling were prospected and/or geologically mapped, with some additional silt, soil or rock sampling.
In 2011, on behalf of Eagle Plains Resources Ltd., a ground-based induced polarization and magnetic geophysical survey over 9.1 line-kilometres was completed in the central zone of the Elsiar property.
