From a metallogenetic standpoint, mineralisation in the Quinchía district is genetically linked to the emplacement of a cluster of Miocene-aged hypabyssal porphyry bodies. A variety of magmatichydrothermal Au (Cu) and Au-Ag (Pb, Zn, Cu) deposit types are associated with the geochemical and cooling history of the porphyry bodies.

Retreat longhole open stoping with backfill is the mining method proposed. This method permits the extraction of the ore at maximum hydraulic radius after backfilling the stopes. The backfill assumed is waste material from mining and fine tailings material. Backfill is required for both stability and environmental reasons, allowing all waste material generated by the mining operation to be redeposited as fill in the mine.

All the mine accesses will be developed in rock mass with good geotechnical conditions. The first 80m of the decline ramp will be developed in basalt before transitioning to breccia.

The process facility is designed to treat 474,500 tonnes of ore per annum (1,300 tonnes per day). The wet plant is scheduled to operate seven days per week at a nominal treatment rate of 59 dry t/h.

Crushing Circuit
A run-of-mine (ROM) pad for storage of ore delivered by mine haul trucks will be established adjacent to the crushing plant feed bin (ROM bin). Ore will be reclaimed from the ROM stockpiles and delivered in the required blend to the ROM bin by a front-end loader.

A three-stage crushing plant will be provided to crush the ROM ore. The crushing plant has been designed to operate five days per week, 12 hours per day, at an effective utilisation of 70%, at a crushing rate of 220 t/h to produce sufficient product for the mill throughput of 474,500 dry t/a. The crushing circuit design will have sufficient capacity to build fine ore stocks to accommodate non-operational periods and tolerate shutdowns for maintenance requirements. The crushing plant pro ........