Impala Platinum and its 87% owned Zimplats Holdings subsidiary announced on August 20 that all mining activity at their Bimha underground platinum mine in Zimbabwe was being shut down due to unstable ground conditions. On July 18, Zimplats had reported a major underground collapse at Bimha that affected nearly 50% of the mining footprint at the mine. The collapse was triggered by the accelerated deterioration of ground conditions associated with the Mutambara Shear, a major shear that transgresses through half of the mining area.
The fault was first identified in 2011 but had become more problematic over the past year, both along the declines and within the stoping footprint of the Bimha mine. Ground conditions continued to deteriorate after mid-July, and as a consequence, on August 20, all employees were withdrawn from high-risk areas, and orderly closure procedures were initiated across the rest of the mine to ensure the safety of underground personnel and equipment.
A team of company and independent advisers was appointed to conduct detailed investigations to re-engineer and/or arrest the mine stability concerns. There was no indication as to when or if the mine would be re-opened. Two mining fleets from the Bimha mine were deployed to the other Zimplats mines to mitigate production losses.
Zimplats produced 240,000 oz of platinum in its 2014 financial year ended June 30. Bimha is the company's largest mine, and the company estimates its shutdown could result in the loss of 70,000 oz during the current financial year. Zimplats does not expect the shutdown to impact production at its other mines.