NSW Mining Methods - NSW MiningOpen-cut mining can be more effective than underground methods, generally recovering 90% of a mineral deposit, and accounts for about 65% of raw coal production in NSW. Open-cut mining is also used for some gold and copper production in NSW. One of Australia's largest open-cut coal mines, BHP Billiton's Mt Arthur.process of open cut mining,Open-Pit Mining Methods - 911 MetallurgistApr 11, 2017 . Open-pit mining methods are applicable to mining ore deposits that apex at or near the surface. If the deposit apexes below the surface, the overburden and barren capping overlying the ore must be removed in advance of open-pit mining. The removal of this material is known as stripping. The stripping-pit.