For higher structures that extended above the safe working level of conventional equipment, Delsan-A.I.M. also employed control-drop methods, either by mechanical means or by using explosives, in order to cause the rapid progressive failure of the structure in a predetermined, controlled, and secure manner.
Specifically, Delsan-A.I.M. utilized explosives to safely and successfully demolish a headframe building. The building, which was located directly above the No. 3 Shaft and housed the hoisting equipment, was a large, reinforced concrete structure with a footprint of 68 ft. by 46 ft., a height of 257 ft., and a wall thickness of 26 inches.
The reinforced concrete floor of the building, which capped the top of the mine shaft, had to be maintained during the course of the work. This challenging demolition operation required careful planning, which Delsan-A.I.M. undertook by preparing a detailed Blast Plan, which included engineered procedures.