The Stillwater Mine, one of the largest underground operations in North America, is a network of levels connected by shafts with hundreds of miles of tunnels and shafts ranging from 2000′ to 9000′ in elevation. The owner issued Purchase Orders that outlined a variety of scopes for this project on an annual basis. Scopes included lateral mine development drill/blast drifts, access tunnel rehabilitation, construction of utility chambers underground, and excavation of ore/muck level connection shafts which were accomplished utilizing air powered Alimak raise climbers during excavation. Every shaft excavated was over 200′, with the longest being a pair of 808′ shafts.  

Drill Tech also mined tunnels ranging from 14′ to 20′ diameter by drill/blast excavation. Although ground support typically consisted of rock bolts (over 100,000 installed in the span of four years) and wire mesh, dry mix shotcrete was installed in several areas of poor ground. Drill Tech’s equipment fleet at Stillwater included multiple high production drill jumbos, bolters, LHDs, and haul trucks.  

Drill Tech’s scope included simultaneous development tunnels, production mining, and Alimak raises miles apart underground that required coordination of equipment and manpower across multiple sites. Coordinating the various crews’ transportation back to the main underground train station at shift change was a significant challenge since some of the work areas required over an hour of travel underground to get to the heading. Drill Tech’s safety program was integrated with that of Stillwater Mine and MSHA.