The objective of this investigation was the development and in-mine testing of an automatic fire control system (afcs) for mobile underground metal mining equipment. Volume I of this report described the tasks through the development of a first generation prototype afcs that was installed on a st-2b-lhd vehicle at the Hecla Lakeshore Project at Casa Grande, Arizona, and on the demonstration of system performance on the vehicle in underground fire tests. Volume II primarily concerns the longterm validation testing of the prototype afcs. Validation testing was performed on the demonstration system plus six additional subsequent generation prototype systems on vehicles in four mines. In addition, work was done to determine the possible personnel exposure hazard presented by multipurpose dry chemical fire extinguishants.