What is the biggest factor that you could control at an open cut coal mine to generate return? For me it would be loss and dilution. Small improvements deliver big increases in cash generation, usually at minimal or no additional cost. Commonly, most of the coal losses occur at top of coal as blast energy breaks up the coal and makes it difficult to separate cleanly from the waste. Big gains can be made by improving blasting practices to avoid fracturing the coal.
The key to driving these gains is to reconcile loss and dilution using an ash and moisture balance to work out the insitu coal component mining recovery. Measuring ROM tonnes recovered against plan does not give you the full picture, as the ROM tonnes can be wetter and contain more dilution than plan, adding tonnes that mask the true extent of coal losses. Compare the ash and moisture of the washplant feed to the insitu ash and moisture from the geological model. The difference in ash will tell you the amount of dilution. The amount of clean coal recovered is the ROM tonnes less the dilution less the change in moisture content.