The Recovery of a Dozer from a Highwall Using Blasting By Tristan Worsey and Tyler Acorn Introduction A dozer operator during the night shift drove a D10 dozer up a berm and off the edge of the highwall. The dozer fell down the highwall 60 ft (18.3 m) before the front blade dug into a catch bench. The dozer operator quickly left the dozer and climbed to safety after the dozer came to a stop on the catch bench. The highwall the dozer drove off was at a 65 degree angle but the dozer sat on the catch bench at a 40 degree angle. Figure 1 shows the dozer caught on the catch bench. At first, hooking onto the dozer's tool bar and dragging it out was suggested, but this was deemed unsafe and damaging to the dozer. Bringing in a crane to lift the dozer was also suggested but in order to access a sufficient tie off point the tool bar would have to be removed. It was deemed unsafe for personnel to do any work on the dozer in the middle of the highwall. The decision was made to excavate down to the bench elevation in order for personnel to be able to work on the dozer from the safety of bench elevation. At first they tried to free dig the material but it soon turned too hard to dig. The blast tech team knew that blasting would be an option if we changed our normal blast design. When excavation was no longer possible the idea of specialized blasting was suggested and management agreed. 30 Figure 1. The day after the dozer drove off the highwall. The Journal of Explosives Engineering January/February 2015