Current reserves at Mayskoye have an estimated depth of 300 m from the surface, with resources extending to a depth of 1,000 m. The primary ore that makes up more than 90 % of the total reserves, is accessed with three separate sets of twin spiral ramps in the central, eastern and western parts of the deposit. This technique allows for greater mining flexibility in terms of tonnage, grade and metallurgical characteristics (sulphur content and organic carbon content).
Several underground mining methods are used at Mayskoye, but more than 80% of ore is mined by sub-level open stoping. Oxidised ore is mined in a series of shallow open pits, as well as the underground. However, due to persistent problems with ore stability that was partly responsible for fatal accidents at the mine, we accelerated a planned changeover from drift-and-fill mining to sublevel open stoping with backfill. The new mining system was designed to ensure that employees are not exposed to the falling rocks in the partially broken stopes since all development and production drilling will be done from waste openings. This new mining method has demonstrated positive dynamics, ensuring lower dilution from secondary stopes and reduced primary stope length.