Dr Dave Collins and James Forsyth
Synergetics Consulting Engineers
Use of compressed air to clean electrical equipment is a routine maintenance task in heavy mining equipment (HME) across the Queensland Mining Industry. During cleaning elevated levels of harmful dust can engulf the compressed air cleaning operator for extended periods and increase the risk of developing lung diseases including pneumoconiosis and silicosis.
In 2017 the Queensland Mines Inspectorate (Department of Natural Resources, Mines and Energy, 2018) reported that approximately 50% of all respirable dust and Respirable Crystalline Silica (RCS) exceedances in surface coal mines were directly related to the use of compressed air for compressed air cleaning of equipment prior to maintenance.
Respiratory protection has historically been viewed as the primary control to protect the health of compressed air cleaning operators, as higher order controls such as engineering controls have not been considered feasible.
The principal of applying engineering controls for compressed air cleaning of haul truck electrical cabinets was reported and demonstrated at the Queensland Mining Industry Health and Safety Conference in 2018 (Worland, Stream, Brett and Collins). Here the electrical cabinets were converted into full enclosures under negative pressure resulting in a physical barrier between the worker and the dust generating compressed air cleaning task.
This paper describes the further development and field testing of engineering controls over the intervening 12 months. Safe compressed air cleaning has now been demonstrated for a broad range of HME including trucks, excavators, dragline MG sets and stationary equipment. The controls incorporate continuous monitoring of airborne particulate with feedback systems to shutdown compressed air and demonstrate that safe compressed air cleaning is achievable.