In the simulation process, it is found that the stability of the
stope after the third step is the worst.
With the advance of heading face, the hanging space of
stope continuously increases, to a certain degree, the overlying strata start to break from bottom to top, which forms the breaking arch [8-10].
Using a stoping dilution at 10% at zero grade and a
stope recovery of 80% mining studies estimated an extraction of 65% of this resource or 878,000 tonnes @ 7.95g/t Au (224,000 ounces) from development and stoping.
VCR
stope layout is standard in all mining areas with a
stope span of 23 m and a 7 m wide rib pillar.
Stope 45-13-0 produced lustrous disphenoids ([less than] 1 mm) intimately associated with sphalerite on gemmy clear quartz crystals.
Lack of mining flexibility required mining
stopes prior to completing ore control drilling which contributed to a lower than expected grade profile.
The company expects to have five
stopes in production on that level by the end of the fiscal year, which closes out on April 30.
Boart Longyear already has over 30 of its new generation
stope drill rigs operating in the platinum and chrome mines of southern Africa.
Of three
stope sizes analyzed, "the 23-m x 11-m long-hole open size was chosen to minimize the number of
stopes, it being the least costly of the options," McKirdy reported.
In massive open stoping areas, the sub-outcrop of the reefs coincides with reduced waste middling between the reefs, and this package of multiple, steep reefs lends itself to the creation of a large massive open
stope. The
stope shape has unsupported sloped sidewalls to improve safety and to channel the broken rock into the trough drive below.
AMC examined the existing fleet of
stope equipment (jumbos, LHDs, long-hole drills, and bolters) at the mine and established optimal drill-and-blast designs for the selected vein widths, dips, drift profiles (square and shanty), drift size (height and width), and mining methods, which could immediately be implemented to reduce dilution, without additional equipment purchases.
