Measurement and modelling of blast movement to reduce ore losses and dilution at Ahafo Gold Mine in Ghana

Abstract

Blast induced rock mass displacement can have a significant impact on grade control. The mischaracterisation of the grade boundaries without proper understanding of blast movement can lead to significant financial losses in terms of ore losses and dilution. Ore dilution occurs when waste material is miscategorised as ore and sent for processing diluting the run of mine head grade and recovery. Ore losses take place when valuable mineral is miscategorised as waste and sent to the waste dumps. The geologists at Newmont Ahafo Mine have realised the impact of blast movement on ore losses and dilution and have implemented a blast movement study to minimise blast induced ore losses and dilution. This paper describes the application of the latest measurements and modelling techniques in understanding the blast dynamics and develops site specific solutions to minimise blast induced dilution and ore losses. These solutions are validated at Newmont Ahafo open pit mine through systematic trials and subsequently incorporated into site standard operating procedures to sustain the benefits.