Both the Eagle River and Mishi deposits are mesothermal lode gold deposits hosted by Archean Greenstone Belts.

The Eagle River deposit has been described as a vein type deposit along a regional deformation zone with discrete brittle-ductile shears localized along lithological contacts (Heather 1986 and 1991).

Gold bearing quartz veins at Eagle River are hosted primarily by subvertical to steeply north dipping east-west striking shear zones within an elliptical quartz diorite stock with dimensions of 2.0 kilometres east-west and 0.5 kilometres north- south.

The quartz diorite stock intrudes a steeply dipping north-facing sequence of thin mafic to intermediate volcanic flows, flow breccias and interflow volcaniclastic rocks.

A number of different ore zones have been distinguished that constitute different segments of the overall shear zone corridor and each has its own gold grade characteristic. Mineable portions of the individual zones form ore shoots that plunge steeply to the east. The bulk of the historic production has come from Zone 8 and Zone 6, which are entirely within the intrusive quartz diorite, while Zone 2 mineralization is hosted in sheared mafic volcanic rocks just east of the stock.

In general, the ore shoots mined to date occur at a spacing of 400 metres along a 2.4 kilometre strikelength. They appear to be spatially related to an array of oblique 110º striking mafic dykes, which pre-date mineralization and deflect into and out of the shear zones.

Gold mineralization is structurally concentrated within highly strained portions of the various quartz veins. Ore microscopy (Clemson, 1989; Johnston, 1990) indicates that 60% of the gold occurs along quartz-sericite grain contacts, 32% along sulphide-gangue contacts and 1.4% within sulphide grains. The grains are generally less than 500 microns, free milling and 40 to 60% recoverable by gravity methods. Gold grains less than 5 microns account for a negligible percent of the total gold. Free gold generally occurs as a multitude of fine grains which result in a relatively low sub sampling variance generating very good assay precision for a vein type gold deposit.

The Mishi deposit is somewhat different. Gold occurs primarily with subordinate, discontinuous quartz veins and lenses. In the Mishi Mine area mineralization is hosted by a series of at least 8 tabular parallel zones consisting of ankerite-sericite ± chlorite alteration zones containing 2-8% fine disseminated and a system of sub conformable, dislocated, smoky grey quartz veinlets and lenses. Veins generally vary from 5-20% of the bulk volume of the zones with individual quartz lenses commonly 5-15 centimetres wide.

The 8 zones recognized to date are labelled from south (footwall) to north (hangingwall) M2, M4, M6, M8, M10, M12, M14 and M16. Zones M2 and M4 are close together and are merged when modelling into a Main Zone. The zones strike 100º, dip north 40º and plunge northeast. In general the zones become more felsic, discrete and vein dominated towards
the north. Additionally, they appear to be converging eastward and possibly diverging westward.

Longhole mining was adopted as the primary mining method at Eagle River Mine in year 2001. The method was experimented with in 2 forms: Conventional Longhole and Sublevel Retreat. Conventional Longhole has been used principally for pillar recovery and non-critical stope production. The method generally uses downholes depending on ore configuration. The hole diameter is 2.5 inches. Downholes are generally drilled at 90° and upholes drilled at 70° to minimize the possibility of loose material striking employees or equipment. Hole lengths are generally limited to 13 metres, however, hole lengths of 15 metres are common. Dilution and bridging has been attributed to hole deviation. More stringent controls are being implemented to limit hole length and hence reduce these occurrences. Results to date with this method have been good.

The Mishi Pit deposit has been designed as an open pit with a planned ore production rate of 160,000 tonnes per year. The mining rate will supplement the 150,000-160,000 tonnes per year currently planned for the underground Eagle River Mine in order to feed the Eagle River Mill, which has a capacity of 320,000 tonnes per year.

Mining will be undertaken by mining contractors using conventional truck and shovel equipment. The selected equipment is a 40-tonne capacity range truck and an excavator of appropriate size for ore and waste assuming a bench height of 5 m. However, the ramp will be located on the footwall side.

Wesdome initially leased then subsequently acquired the former Magnacon mill and tailings facilities in 1996. The mill is 17 kilometres by road from the mine. The mill capacity was increased from 600 to 1,000 tonnes per day in 1999. Even though the addition of the cone crusher expanded capacity to the permitted level of 1,200 tonnes per day on a crushing basis, required maintenance time means the practical limit is approximately 1,050 tonnes per day as it is configured to achieve targeted gold recoveries.

The mill employs the Merrill-Crowe process for the recovery of gold from Eagle River ore with about 40% of the gold recovered into a gravity concentrate using a Knelson concentrator. The Merrill-Crowe process involves cyanide solution and zinc precipitation. Precipitate is refined on site to produce doré bars containing approximately 80%-92% gold. By-product silver is recovered at a rate of one part for every six to ten parts of gold. The doré bars are shipped to the Royal Canadian Mint in Ottawa for refining. Overall mill recoveries for Eagle River is around 95% and for Mishi ore around 87%.

The mill tailings commonly averages grades of 0.25-0.50 g/t are deposited in the tailings pond. Water from this pond is reclaimed for use in the mill process as required to minimize the discharge of effluent. The mill operates 24 hours per day, seven days per week with two crews working 12 hour shifts on a seven days in, seven days out rotation.