Sustainability website / Case Studies 2007 / Xstrata coal / Reducing operators’ noise exposure at the Tavistock mine

Reducing operators’ noise exposure at the Tavistock mine

NIHL accounted for over half of Xstrata’s new occupational illnesses reported in 2007. In line with Xstrata’s group-wide Sustainable Development Policy of working towards eliminating work-related illnesses, Xstrata Coal South Africa is looking at ways of reducing noise exposure in its mines and has recently undertaken an initiative to reduce noise emissions at its Tavistock mine.

Xstrata Coal’s Tavistock complex in South Africa consists of both underground and open cast mines. Load Haul Dumpers (LHDs) are used extensively at the underground mine sites where they operate in areas with restricted space and with low ceilings, leading to high levels of noise exposure for the LHD operator. The operators are provided with hearing protection devices to reduce the level of noise and help prevent NIHL.

During 2007, engineers at Xstrata Coal SA redesigned the drivers’ cabins of the Wright HD356 LHDs in use at the mine to improve the insulation from noise. These cabins were originally open air with the engine of the LHD located directly behind the operator. Following the redesign, the cabins are enclosed and ventilation has been installed.

Various tests were then carried out to measure the effectiveness and safety of the new cabin design with the measurements of the test results being used as a best practice guide within the Chamber of Mines’ Milestones for Occupational Safety and Health Working Group. The results have shown a significant reduction in the noise exposure to the LHD operator. A prior measurement of the noise emissions of a typical LHD in the underground environment showed an average operator exposure of 97.7 decibels, while the study of the operator’s exposure in the improved cabin design, taking into account the noise emission of the LHD, was 72.9 decibels. This dramatic reduction in noise exposure means our operators no longer require hearing protection when in the cabins.

Although successful in reducing noise levels, there are still a number of challenges that need to be overcome. It was discovered during the trials that the cabin redesign resulted in the driver’s view being obstructed by the framework supporting the roof and condensation on the windows. The engineering department is currently working to overcome these issues.

Shane Ambrosio, Group Health and Hygiene Manager, Xstrata Coal South Africa said: “We are pleased with the results of this initiative despite some ongoing challenges. The main benefit is the reduced noise exposure to the LHD operator and the prevention of noise induced hearing loss.”

This initiative is one of several currently being undertaken by Xstrata Coal with the aim of reducing noise emissions and eliminating NIHL in the coal mining industry. Xstrata Coal South Africa’s own target for the elimination of NIHL states that by December 2013 the total noise emitted by all equipment installed in any workplace must not exceed a sound pressure level of 110 decibels at any location in that workplace.

As part of this process, Xstrata Coal SA is working closely with the Mine Ventilation Society of SA (Coal Branch) and the Chamber of Mines – Group Environmental Engineers Committee and is involved in a number of forums designed to share ideas and encourage collaboration within the coal mining industry.