Open pit mining is the process of mining a near surface deposit by means of a surface pit excavated using one or more horizontal benches. The term open pit mining is usually used for metallic or non-metallic deposits and sparingly used for bedded deposits like coal. A quarry is a type of open pit mine used to mine building materials (construction aggregate, riprap, sand and gravel) and dimension stones usually at shallower depths. The term quarry has traditionally been used to mine stones.
The majority of open pit mining machine in Australia currently operate using discontinuous shovel/truck systems. These systems are favoured as they enable; (i) mining capacity to be progressively scaled up over the life of a mine; (ii) the use of narrow benches that defer the high costs of stripping, and (iii) flexibility to rapidly adapt mine plans in the face of uncertainties caused by changing commodity prices or unexpected variability in ore grades.
A mining student is currently investigating the Net Present Value impact of adopting "deep-then-wide" strategies for repositioning crusher stations in deep open pit gold operations for his final year honours project.