The Century Mine TSF is approximately 2.7km long (north-south) and 2.2km wide (east-west). The tailings resource in the northern end of the TSF is approximately 10m deep while the resource is approximately 22m deep in the south-eastern corner, with an average thickness of 13m.

The Century Tailings Deposit is to be mined utilising the hydraulic mining method. At a capacity of 15Mtpa, this process will involve the use of five track mounted monitor units; four actively working individual faces throughout the Deposit and one on standby.

The Deposit will be mined in 8m deep benches which dip at 0.5% to the north and south sumps. Cuts will be done utilising a top down mining method at 18° utilising a 6m standoff from the monitor tracks to the edge of bench. The main production phase will mine the Deposit leaving a 300mm loss on the floor of the deposit while taking 100mm of dilution in the main production pass.

A separate clean-up crew will follow the production crew after a period of time, in order to remove the remaining contaminated material and an additional 100mm of dilution. This material will be mostly bypassed to the open pit void as waste. This clean up forms part of the final rehabilitation process for the TSF area.

The mine design has two sumps, which provides greater flexibility in the mine plan, and reduces the risk of significant downtime during heavy rain events.

Tailings slurry from hydraulic mining will be passed over a trash screens before being sent to a feed thickener. The purpose of the feed thickener is to ensure consistent density and flow rate into the Century Processing Plant. The Plant will have sufficient surge capacity for 2 hours of production to further assist in smoothing production.

Thickened slurry is sent to the classification circuit (cyclones) where the +53µm size fraction will be sent to one of the existing ball mills in an open circuit arrangement.

Milled material will be combined with cyclone overflow and sent to one of two parallel flotation circuits. The flotation circuit consists of rougher, scavenger and cleaner circuits in each train. Regrind mills are used on cleaner 1 concentrates to improve recovery of zinc.

The final zinc concentrate is thickened and pumped to concentrate storage tanks prior to being pumped to the Karumba Port facility via the underground slurry pipeline.

Residue from the reprocessed tailings are pumped to the existing open pit for ultimate disposal via sub-aqueous deposition. The transport and deposition of tailings back into the original open pit at Century provides the ultimate mechanism for progressive mine site rehabilitation.

Operation of the mine and plant will be in stages for the systematic expansion of hydraulic mining operations. In order to reach capacity of 15Mtpa, further minor modifications to the Century Processing Plant will be carried out. This includes the installation of an additional seven 100m3 float cells and four regrind mills during the first 15 months of operations, to increase the throughput to a design capacity of 15Mtpa on tailings.

The concentrate produced by the proposed operations at Century is expected to contain on average 52% zinc and 187g/t silver.