The Copper Cliff deposit consists of numerous mineralized zones. The major zones include the actively-mined 120, 100, 900, 880, 865, 860, 830, 810 orebodies, and the currently inactive 191, 178, 138, 890, 850, 790, 740, 725, and 712 zones. Copper Cliff is predominantly an Offset-style deposit with associated minor Contact- and Footwalltype mineralization styles. Mineralization is hosted in a quartz–diorite dyke, the Copper Cliff Offset, which strikes 15 km south into footwall rocks from the base of the SIC, is steeply dipping, and averages 40 m wide. The Copper Cliff Offset is cut by narrow aplitic, quartz diabase, and olivine diabase dykes, locally referred to as “trap dykes”. Contact-style mineralization associated with Sublayer norite is present in the North Copper Cliff mine area. Sudbury Breccia occurs in footwall rocks adjacent to the Copper Cliff Offset. STRUCTURE The Copper Cliff Offset is affected by post-impact displacement along the Creighton and Murray faults and several smaller splay faults. The Copper Cliff Offset is folded about northeasterly-trending open fold axes that have steeplydipping axial planes. Folding of the quartz–diorite dyke is confined to part of the dyke south of the Creighton fault. West-trending diabase and northwest-trending olivine diabase dykes post-date the folding. MINERALIZATION The sulphide mineralization is mainly associated with coarser grained quartz diorite and rarely crosscuts footwall rocks. Mineralization consists of dis ........

Slot–slash, Vertical retreat, Uppers retreat, Mechanized cut-and-fill (Post-pillar, Drift-and-fill) mining methods are employed for ore extraction. Mill rock tailings are used for backfilling. Slot–Slash Slot–slash mining is a bulk mining method that entails blasting vertical slices of ore to a free face, which initially will be a blasted inverse raise, or a bored raise. The amount of ore that can be blasted at any given time is limited to the existing void space and the available free face. Blastholes are loaded with staggered decks to break anywhere from 6 m to the entire length of the hole. The blocks are slashed out to the stope boundaries and up to a crown. The final crown is taken in one blast. This method concentrates loading and blasting operations, and, once a slot has been established, stopes of 25,000–40,000 t of ore can be completely broken in 3–5 separate blasts, while smaller stopes can be blasted in one blast. Blastholes are drilled using in-the-hole (ITH) drills. Prior to blasting, long blastholes are surveyed in order to determine their location and all holes are probed with a conductivity probe to confirm ore limits. If required, new holes are drilled to reduce burdens created by drilling inaccuracy and to blast additional ore found during the conductivity tests. Slot–slash mining maximizes the availability of broken ore and increases the efficiency of stope service operations without compromising muck (waste) fragmentation. The walls of the stope a ........

Ore is trammed to the 2639 ore pass (on the 2,600 and 3,400 Levels) or dumped directly into the crusher (on the 3,935 Level); Crushed ore is hoisted to surface through #1 Shaft in 13.6 t skips that have a capacity of 270 t/hr; Ore is then trucked to surface stockpiles for blending with other ore sources to meet milling requirements. Clarabelle Mill In 2017, the crushing plant and rod mill circuit was put on care and maintenance and the Clarabelle Mill became a SAG-only operating plant. The ore feeds the semi-autogenous grind (SAG) mill where ore is ground with added water. Discharge passes through a trommel; coarse trommel oversize material is transferred back to the tipple building by conveyor, while the trommel undersize is pumped to vibrating screens located near the feed of the SAG mill. Screen oversize is fed back into the SAG mill while the screen undersize is pumped to the ball mill feed distribution pumping system; Product from primary grinding circuit feeds the ball mill feed distribution system, which can send slurry to the cyclone feed pumpboxes of six ball mills. Each ball mill in combination with its own cyclone system grinds the material to a target of 80% passing 150 µm (106 µm for sulphides). Once the material is ground to the correct size, the slurry is sent to flotation.

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