Reverse Circulation (RC) Grade Control Drilling, also known as in-pit grade control, is employed in open cut mining operations to accurately determine ore grades and provide essential data for mine planning and blasting activities.

Typically, RC/GC drilling is conducted to optimal depths of up to 50 meters, with hole diameters ranging from 125 to 140 millimeters.

This practice is critical in minimizing waste rock (dilution) in the concentrator feed, as the extent of dilution can vary significantly. RC grade control is recognized as the most cost-effective and precise method for delineating the boundaries between waste rock and ore bodies.