How 3D seismic can help enhance mining

This paper demonstrates the impact of a high-resolution 3D seismic survey on the development program of the Karee platinum mine in South Africa, and shows that reflection seismology can play an important role in positioning the structural position of thin, layered ore bodies. This case history shows that seismic methods are capable not only of directly detecting sub-metric layered platinum ore bodies at depths of 800 m, but they can also help the mining industry to optimize mine-planning in a cost effective manner. For such shallow targets, compared with the more traditional oilfields, the acquisition parameters were tuned to meet the survey’s objectives, including a bin size of 7.5  7.5 m2 and a fold of 28. This led to a very high density of shots per km2 of almost 900. The vibroseis source was well adapted to the surface conditions of the area. After full 3D processing, the seismic data provided a clear image of the structures of the Merensky and UG2 reef horizons and led to a significant increase in the level of confidence. In addition, effective application of new advanced seismic processing and visualization software used in the oil industry also made it possible to accurately highlight some geological features which disrupt the platinum reef horizons, such as slump structures (known as potholes), faults, pegmatoid bodies and dykes. These disturbances are of prime importance for implementing galleries, optimizing reef extraction, mining engineering and positioning the shafts. Their interpretation helped optimize mining in a significant, cost-effective way. This article is adapted from a paper presented at the SAGA conference in South Africa in October 2001 and was also presented in the ‘Mining and Best of Saga’ session at the 64th EAGE Conference in Florence.