The DM zone is similar to the Crescent deposit (092INE026) 1000 metres to the east, including a location along the contact between the Pothook and Cherry Creek intrusions, early pervasive alteration followed by a similar sequence of vein types, and disruption by faults. The DM zone is hosted by intrusive rocks of the Pothook and Cherry Creek units of the Late Triassic-Early Jurassic Iron Mask batholith. Most of the DM zone lies between the South (SFZ) and North (NFZ) Fault zones, which are wide, composite, subparallel zones which strike 050 to 060 degrees and dip about 70 degrees to the southeast. Hydrothermal effects are not evident south of the SFZ, but alteration occurs on both sides of the NFZ. The NW Fault, which strikes about 325 degrees and dips steeply to the west, cuts and displaces the NFZ, SFZ and mineralization. Other major faults include the South Splay Fault, which varies markedly in orientation along its length, and the NE Fault which trends about 020 degrees and dips steeply to the west. Although the relative timing and sense of movement of the faults is not well constrained, most displacement occurred after Jurassic magmatic and hydrothermal activity. Strongly brecciated rocks lie both along and between the NFZ and SFZ but are predominantly intrusion rather than fault breccias. The boundaries between the major intrusive rock types in the DM deposit coincide, in part, with the NFZ and SFZ. To the south of the SFZ lies unaltered Pothook unit diorite. North of the NFZ lies a pyroxene diorite or monzodiorite which is macroscopically similar to the Cherry Creek intrusion exposed in the Crescent deposit. Locally, this pyroxene diorite grades laterally into strongly altered intrusion breccia. Between the main fault zones lies both Cherry Creek and Pothook units which each exhibit various degrees of alteration, and abundant intrusion breccia with fragments of altered Pothook diorite in a matrix of Cherry Creek monzodiorite. The contact between the Cherry Creek and Pothook intrusions lies near the SFZ, but interfingering of the two units and intense potassium metasomatism obscures its exact location. All gradations appear to exist between unaltered pyroxene diorite, Cherry Creek intrusion breccia and unaltered and altered Pothook diorite, and together these rock types form a continuum resulting from various degrees of alteration and intrusion breccia development. In several locations throughout the DM zone, diorite dikes which range in width from one to five metres and which contain prismatic, locally trachytic, euhedral hornblende phenocrysts are interpreted as Sugarloaf diorite. In surface trenches, these dikes trend northeasterly, but it is not yet known if this orientation is consistently developed. Weakly altered plagioclase diorite porphyry dikes and minor postmineral andesite dikes similar to those in the Crescent deposit are also present.
Mineralization in the DM deposit occurs in two pipe-like bodies which dip steeply to the south and which converge at depth. Both ore zones occur in rock characterized by intrusion breccias, with lesser mineralization hosted by unbrecciated rock. Alteration in the DM zone is nearly identical to that observed in the Crescent deposit. Pervasive, locally magnetite destructive potassium metasomatism introduced little or no sulphide and formed preferentially in intrusion breccia along the contact between the Pothook and Cherry Creek intrusions. Pervasive alteration was followed by a sequence of veins similar to that at the Crescent deposit but which includes two additional varieties. In the DM zone most sulphide mineralization was introduced by chlorite-sulphide veins, but quartz dominated veins with abundant sulphide which formed early in the paragenesis also carry significant copper mineralization. Locally, quartz abundance reaches 15 per cent. Late stage veins dominated by gypsum are abundant in the northern part of the DM zone. A second, sulphide bearing variety of gypsum vein is reported to have formed earlier in the sequence. Quartz veins have a preferred orientation of 290 degrees and dip 60 to 70 degrees to the southwest but data are not available for other vein types. Magmatic hydrothermal breccias are minor but fault breccias are common. The major ore mineral is chalcopyrite. Bornite is locally important as disseminated grains along the footwall of the SFZ. Pyrite is abundant both in and peripheral to the ore zone, but its distribution is truncated by the SFZ. Pyrite is present with chalcopyrite but not with bornite. Supergene oxidation has converted copper sulphides to copper carbonates and minor native copper in a shallow zone of weathering, but no enrichment has occurred. Reserves of the DM zone are stated as 2,685,000 tonnes grading 0.38 per cent copper and 0.27 gram per tonne gold (CIM Special Volume 46).
The Audra zone is about 600 metres east of the DM zone, almost equidistant from the Crescent deposit.
The property is located west of Ironmask Lake approximately 11 kilometres west of Kamloops. An area roughly identified as lying between Ironmask Lake and the DM shaft has been held for many years by a number of Crown grants and various located claim groups. The Truth group, comprising the Truth, Dakota, Hope, Jennie, and Pearl claims was owned by A.G. McDonald and Joseph McGee. Development working during the period 1899 to 1906 inclusive included a shaft to 24.3 metres with a 30.4-metre drift from it. A second shaft was sunk to 9.1 metres and an adit was driven more than 30.4 metres to drain the workings. Ore mined in 1906 was sold to the nearby Iron Mask operation (092INE010) for fluxing purposes. Berens River Mines Limited, a subsidiary of Newmont Mining Corporation, held a number of claims in 1952. Graham Bousquet Gold Mines, Limited in 1956 acquired the DM group, in part a restaking of the Truth group, and other claims in the vicinity. Work included geophysical and geochemical surveys. The company amalgamated with several other companies in 1958 to form Cadamet Mines Limited. Noranda Exploration Company, Limited optioned the property in 1958 and carried out further geophysical surveys. The option was given up later in the year. Comet Mining Corporation Ltd., incorporated December 1964, optioned the Lorna 1-4 claims from Lorne H. Stephens. The company also acquired the Iron Cap and some 62 located claims in the RO, DM and Monzo groups. In 1965, Vanco Explorations Limited optioned this and a number of adjacent properties. Work by the company included geological, geophysical and geochemical surveys. Diamond drilling totalling 1612.3 metres in 15 holes was carried out on the Lorna claims. The option was terminated in May 1966. Comet Mining and Krain Copper Resources Ltd. amalgamated in May 1966 to form Comet Krain Mining Corp. Ltd. In October 1966, the company optioned the Con Verdant, May Fraction, Sodium Fraction and Winty Crown grants from Isabelle Wintemute. The company name, Comet Krain was changed in April 1971 to Comet Industries Ltd. An exploration and development option agreement was made in January 1972 with Initial Developers Corporation Limited, an associate company. Work by Initial on the Lorna, DM and HO groups included geological mapping, magnetometer, electromagnetic and induced polarization surveys over 48 line kilometres, a geochemical survey, 2286 metres of diamond drilling in 25 holes, and 2011.6 metres of percussion drilling in 22 holes. Work on adjacent groups (EB, ID and RO 47-52) owned by Initial included magnetometer, induced polarization and electromagnetic surveys over 16 line kilometres. This work "indicated some 2,267,750 tonnes mineable reserves assaying 0.5 per cent copper in the Crescent zone (092INE026)" (Western Miner, October 1972, page 85). In December 1972, Getty Mining Pacific, Limited optioned 120 contiguous claims in the combined properties (Victor, Iron Mask, Iron Cap and DM) held by Comet, Initial and Davenport. Work by Getty in 1973 included an induced polarization survey over 93 line kilometres, a magnetometer survey over 86.9 line kilometres, 2084.5 metres of rotary drilling in 8 holes, 564.4 metres of diamond drilling in 2 holes, and 15,513.4 metres of percussion drilling in 159 holes. Among these holes, 25 were spaced over a 3 by 4.8 kilometre area. The option was given up in 1974. Davenport Oil & Mining changed its name in 1973 to Davenport Industries Ltd. Initial Developers Corporation in May 1974 amalgamated with North Pacific Mines Ltd. under the name Initial Developers Limited. Canadian Superior Exploration Limited optioned the above combined properties (some 2185 hectares) in 1975. Work in 1976-78 included a magnetometer survey over 89 line kilometres, 8064 metres of diamond drilling in 47 holes and 4211 metres of percussion drilling in 48 holes. The option was terminated in 1978. Craigmont Mines Limited in February 1981 obtained an exploration agreement on the above four properties and on the adjacent Rainbow property (092INE028) of Pacific Seadrift Resources. Craigmont completed some 5791.2 metres of diamond drilling in a 7 month program. This work indicated insufficient tonnage and the option was terminated in September 1981. Comet Industries Ltd in 1983 carried out exploration on the combined Lorna, Iron Cap and DM properties, including magnetometer and electromagnetic surveys over 13 kilometres and 294 metres of diamond drilling in 3 holes. Work reported on the Lorna and DM in 1986 included geochemical sampling (50) and 209 metres of diamond drilling in 2 BQ size holes.
In 2004, Abacus Mining conducted a very aggressive exploration program on their large Afton area property. Work included a large 3-D induced polarization survey and more than 27,000 metres of drilling, split between the Rainbow deposit (092INE026), the DM-Audra-Crescent area, and the Coquihalla zone. Abacus’ work in this area in 2004 had several encouraging drillholes including 308.9 metres grading 0.42 per cent copper and 0.20 gram per tonne gold in a hole through the DM deposit, and 98 metres grading 0.45 per cent copper and 0.60 gram per tonne gold in a hole at the Audra (Exploration and Mining in BC 2004, page 58). The latter is located between the DM deposit and the Crescent pit (092INE026), where Teck mined a small amount of ore in 1988-89. On the DM zone, drilling by the company and previous operators has defined a zone of copper-gold mineralization up to 200 metres in depth within an area 150 metres by 350 metres. The zone is open on three sides and at depth. The historical drilling indicates that two known mineralized DM intrusive breccia bodies appear to be coalescing at depth. On a larger scale, geophysical induced polarization anomalies also indicate that the DM, Audra and Crescent zones may also join at depth.
The following resource figures were reported in The Northern Miner on July 7, 2005. The DM-Audra-Crescent area hosts a drill-indicated resource of 59.9 million tonnes at 0.217 per cent copper and 0.116 gram gold at an 0.1 per cent copper cutoff grade. This drops to 6.3 million tonnes at 0.437 per cent copper and 0.246 gram gold at a cutoff grade of 0.35 per cent copper. The DM-Audra-Crescent area also hosts an inferred resource of 48.9 million tonnes at 0.186 per cent copper and 0.081 gram gold at a cutoff grade of 0.1 per cent copper, or 2.7 million tonnes at 0.393 per cent copper and 0.18 gram gold if the cutoff is raised to 0.35 per cent.
See Rainbow (092INE028) for further details.