This report describes the development, field testing, and evaluation of a new method of investigating mining accidents. Initial testing of these techniques began at five mines owned by two mining companies, followed by further evaluation data obtained from four surface and two underground mines operated by five additional companies. Altogether, there were 170 loss incidents investigated at the cooperating mines using the methodology under evaluation. These loss incidents included injuries, property damage accidents, production losses, and other events generally referred to as "near misses." Volume I of this report discusses the background research, the design of the methodology, and the preliminary field tests in Utah mines.