Safety issues and the use of software-controlled equipment in the mining industry

Equipment control functions that were once hardwired are being implemented with software and very large scale integrated (VLSI) devices. Often this transition has resulted in increased flexibility, improved quality and decreased costs. At the same time, it has created new concerns and challenges concerning worker safety. The visible and well-defined ladder diagram for relay-logic has been replaced by programs in which the exact outcome for varied inputs can be more obscure. In the coal mining industry, efforts to automate longwall mining systems have resulted in semiautonomous machines operating within the same space as workers. This paper describes an effort initiated by the National Institute for Occupational Safety and Health (NIOSH) to identify the safety issues related to the use of processor-controlled equipment in mining. Specific findings in the areas of human factors, hardware and software safety are presented in this paper, and a brief description of a plan to address identified weaknesses is given.