WorldWide Drilling Resource

35 WorldWide Drilling Resource ® JANUARY 2021 New Reaming Bit for Drill and Blast Operations Adapted from Information by Rockmore International Reaming type bits in underground drilling and blasting operations are used to enlarge certain existing blastholes to bigger diameters for effective blasting and rock fragmentation. This is typically performed in tunnelling, mining, and underground construction drilling opera- tions. The larger reamed holes are not loaded with blasting agents and therefore allow the rock formation to implode during the explosion phase. The empty voids in these reamed holes promote better rock fragmentation and more efficient blasting patterns. After blastholes are drilled in the tunnel face with hole diameters ranging from around 1½-2 inches, certain holes in the pattern are enlarged with a typical reaming bit to approxi- mately 3-4 inches, depending on the blast and rock formation requirements. Standard ream- ing bits feature face designs with dome or narrow nose fronts and are intended to effectively enlarge a predrilled hole. When they are retrieved out of the hole, however, at the end of the target hole depth, they often seize up due to the loose rock debris inside the hole formation. “Our field support engineers recognized the need for better bit retrieval in face drilling operations. After close collaboration with various drilling teams, our designers introduced the innovative retrac fea- tures in this new reaming bit,” stated Pejman Eghdami, executive vice presi- dent of Rockmore International. Rockmore engineers addressed the challenge of retrieving these style bits by developing this new model featuring retrac style cutting fins in the rear section to promote better retraction out of the hole. The fins effectively push out any rock chips trapped behind the bit when the drill string is pulled from the blast- hole, resulting in more efficient reaming operations in underground drilling opera- tions. The particular model shown is designed to ream from roughly 1½-4-inch holes and configured with a R32 thread connection to the tunnelling rod. Rockmore International is a global leader in the design and manufacture of rock drilling tools since 1948. EXB March Issue Deadlines! Space Reservation: January 25 th Display & Classified Ad Copy: February 1 st