Core recovery rate is a quantitative metric that expresses the efficiency and effectiveness of a drilling program in recovering intact rock core from a borehole, typically reported as a percentage and calculated over individual drilling runs, specific geological intervals, or entire boreholes. The core recovery rate is closely related to core recovery but is often used in a more operational and performance management context, particularly in mining projects where drilling contractors are assessed against contractual standards. In bauxite, gold, iron ore, and diamond mining, achieving high core recovery rates is essential for ensuring the validity and representativeness of geological and grade data used in resource estimation and mine planning. A core recovery rate below acceptable thresholds (commonly 85–95% depending on the rock type and project requirements) may trigger the redrilling of intervals, the use of different core barrel types, or a change in drilling fluid to improve sample recovery. In resource reporting under standards such as JORC (Australasian Joint Ore Reserves Committee), NI 43-101 (Canada), or SAMREC (South Africa), the core recovery rate must be documented and disclosed, as low recovery rates can affect the reliability of the reported resource estimate. In gold mining, particularly in structurally complex, shear-hosted deposits, maintaining a consistently high core recovery rate is challenging but critical for accurate grade characterisation. In diamond exploration through kimberlite, the recovery rate directly affects the confidence in diamond size frequency distribution studies. Core recovery rate data is typically tracked daily in drilling logs, reported in monthly drilling summaries, and stored in the project's geological database.
