Protecting Mining Environments from Blasting through Impact Prediction Studies

A surface gold mine wishes to develop a new pit (Pit A) as part of its mining schedules. The proposed pit outline is about 300 m to the closest community. Blasting operations in Pit A would potentially create undesirable environmental impacts including fly rocks, ground vibrations and air blasts to neighbouring communities. Integration of proper planning tools or protocols for blasting at Pit A is the major concern of the Mine. Due to safety reasons, management wishes to explore the best blasting protocols that will restrain any blast impact to a 250 m buffer from the proposed pit outline. The Kuz-Ram fragmentation model was used to generate the optimal geometric parameters required for blasting at Pit A. Ground vibration, air blasts and fly rock impact prediction models were used to estimate the associated blast impacts to the neighbouring community. The predictions were made for blasting the oxides, transition and fresh rock formations to be encountered in Pit A. The predicted ground vibration and air blast levels were compared with the Ghanaian regulatory threshold of 2 mm/s. The predicted maximum fly rock distance (235 m) from the pit outline is within the established 250 m clearance buffer zone. The geometric drill and blast parameters and associated single-hole firing charges were used in the prediction models. The predicted results from this study will assist the surface gold mine to properly execute safe blasting operations with minimal impact to the neighbouring community. Due to known scattering of NONEL explosives in initiation systems, electronic initiation systems are recommended for blasting in the new pit.