The demand for labor increased when open-pit mining in the late 1880s and vertical shaft mining was begun.
Other historic waste disposal methods included 'sea icing' (dumping waste onto sea ice that breaks away and drifts out to sea), dumping directly to sea, and open-pit burning.
It is an open-pit, run-of-mine, heap leach gold mine with conventional heap leaching technology and carbon absorption for ore treatment.
A former open-pit coal mine, the lake was flooded in 1999 with groundwater and developed as a water recreation area.
The mine has an annual production capacity of 29.5 million tonnes of iron ore, sourced from open-pit operations.
Surface mining of oil shale deposits causes the usual environmental impacts of open-pit mining.
This may be done by open-pit (also called open-cast mining) or by various surface excavating equipment or tunneling equipment.
The mine is an open-pit mine producing copper, molybdenum, rhenium and silver with minor gold and zinc.
