Lucky Friday | mining
The principal mining method at the Lucky Friday unit is ramp access, cut and fill. This method utilizes rubber-tired equipment to access the veins through ramps developed outside of the orebody. Once a cut is taken along the strike of the vein, it is backfilled with cemented tailings and the next cut is accessed, either above or below, from the ramp system.
There are three main phases to the mining process: development, production, and backfilling.
development – the tunneling or accessing phase
Using plans from the geology and engineering departments, miners drive tunnels 12ft high by 12ft wide to access the various ore zones to be mined.
production – the extraction phase
The method of extraction depends upon the geological nature of the orebody involved. Some of the narrower orebodies can be extracted using conventional mining methods (slushers and jackleg drills), mining as narrow as three feet. In other, more massive orebodies, mechanized mining methods are employed using large rubber-tired equipment to mine widths of up to 20 feet.
The voids created during the production phase are filled up with a combination of mill waste (tailings) and cement. This “backfilling” process stabilizes the production voids and allows extraction of the ore beside, above, and even below the backfilled area.
