Jinfeng mining commenced as an open pit operation in 2006, with production rates designed to gradually increase to match the initial process feed requirements.
To defer some of the waste stripping to later years, the open pit operation has been designed in five stages.
The current pit development is within Stage 3, which has a final floor at 465 mRL.
Stage 4 pit is the last cut-back of the main pit (Huangchangguo (HCG)) orebody. It will extend the pit bottom to 450 mRL and expand the pit in all directions, but mainly target ore along strike to the east. The contiguous Stage 5 pit, which mines a satellite orebody (Rongban), is planned to commence after completing the Stage 4 pit.
Bench heights in the final pit are 10 m; however, in the lower benches this is stacked to an effective height of 20 m. Ore will be mined using 5 m operating bench heights with 2.5 m flitches to optimize ore extraction. Within the pit, the haul road width varies from 18 m for most of its length to 14 m near the bottom of the pit, with a nominal 10% gradient. Haul road widths outside the pit are 20 m wide. The external haul road enters the open pit mining area at 590 mRL.
Only one mining method, overhand cut-and-fill, is used in Jinfeng’s underground operations due to the poor geotechnical ground conditions and the selectivity required for optimal extraction. Mining depths are currently within 100 m to 350 m vertically below the surface. The ore, p ........