The Tom and Jason deposits are examples of stratiform, strata-bound sediment-hosted, exhalative (“SEDEX”) zinc-lead-silver-barite deposits (Goodfellow et al., 1993; Leach et al., 2005; Goodfellow et al., 2007; Goodfellow, 2007).

Zinc-lead-silver-barite mineralisation at the Tom deposit varies from well laminated and stratiform (parallel to sedimentary layering) to a brecciated stockwork zone adjacent to the Tom normal fault. The Tom West and Tom East zones, both of which are exposed at surface, are interpreted to have formed one continuous strata-bound controlled lens prior to folding and faulting of the Tom Sequence, whereas the Southeast Zone is interpreted to have formed in a separate sub-basin to the main graben structure hosting the Tom West and Tom East zones (Goodfellow, 1991). All three zones have been affected by folding, with evidence for the possible development of a crenulation cleavage as opposed to the chaotic folding of laminae due to soft-sediment deformation. Ferroan carbonate alteration and quartz veining are common in footwall conglomerates near vent facies at Tom West.

The Tom West Zone dips 60° to the southwest, has a strike extent of approximately 1 km and extends up to 400 m down dip. It is about 40 m thick at its widest point and breaks into two discrete layers in the centre at depth. Contacts vary from transition over <1 m or are faulted and abrupt. The highest-grade portion of the Tom West Zone occurs along the southern and nea ........

Given the outcropping nature and deep vertical extension of both Tom and Jason deposits, several zones were reviewed for both open pit and underground potential.

Initial material will be recovered at a rate of about 5,000 tonnes per day by conventional truck and shovel surface mining from both the Tom and Jason deposits. During the third year, production will transition to underground mining. Stopes will be filled with a combination of waste rock and paste and cemented rock fill.

Open pit mining accounts for 13% or 4.2M tonnes of the total 32.7M tonnes of material mined and processed. VCR and LH methods account for 75% of the material mined and processed by underground methods.

Mining recovery and dilution factors were applied by mining method. Average open pit mining recovery and dilution were 95% and 10% respectively. Average underground mining recovery and dilution were 92% and 21% respectively.

Existing surface roads and underground development will be rehabilitated and utilized as part of the mine plan. Mine access portals at multiple elevations are planned to maximize natural ventilation and dewatering of underground operations. Open pits have been designed to maintain safe working distance from all major water ways.

Diesel powered mobile equipment would be used to conduct all open pit and underground mining activities. Underground crushing and conveying would provide low cost mineral transport from the Tom deposit, ........

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