Porcupine, consists of the Hollinger open pit and Hoyle pond underground operations, located in the city of Timmins, Ontario, as well as the Borden underground operation, located near the town of Chapleau, Ontario. Borden mine is the world’s first all-electric underground mine.
Approximately 60% of the gold comes from the Hoyle Pond underground mine, where mechanized cut and fill and longhole mining methods are used to extract the ore, and the remaining ore comes from the Hollinger Open Pit mine. The Dome Underground mine ceased operations in 2017.
Hollinger Open Pit mine
There is sufficient grade at specific gold price-points to mine a 150m deep pit, with the rock being processed at the nearby Dome Mine mill. The voids (sub-vertical stopes, shafts, and connecting drifts/drives) are sometimes spaced nearly 20-50m apart extending several hundred metres deep in a 2km square area beneath the City. The pit design was constrained by a regional highway (and the City’s water tower) along the northern wall, with homes and businesses on all other sides of the Property.
The Hollinger is being mined using three 6m and two 9m cuts making up 18m high benches in mostly FAIR to GOOD ground. All blasting is done with blast-mats to reduce fly-rock and noise. Because the mine is in-town, damage needs to be minimised. Earlier, blast trials were conducted to determine the depth of blast-damage induced by varying sizes of confined blasts. These trials indicat ........
