New Innovative Drilling Bit for Straighter Blast Holes and Improved Productivity


Schiff, Eric A. and Thompson, Malcolm J. and Madan, ArunTanaka Kazunobu and LeComber, Peter G.


In most blasting, a uniform powder factor is required. It is the position of the loaded portions of the holes relative to the face and each other that is important (especially at the toe) rather than the surface which is stemmed. For drilling to any significant depth, straight parallel holes are imperative. Too much blast hole deviation or wander in long holes produces poor results and compromises safety. Specific problems include; concentration of charges (holes too close), inadequate charge (holes too far apart), choking or excessive throw (varying burden) and life threatening flyrock (holes too near face). Excessive wander also increases blasting costs as more holes and powder are needed and hole depth is limited. The latter is most important in underground, high precision drill and blast operations such as VCR. A new innovative full body drill bit coined the Rock Reammer has been developed that solves these problems by making straight clean holes which are easy to load. Other improvements in performance over conventional bits include increased penetration rates, faster retraction, far less hang ups and increased bit life. The body of the paper discusses; how drill hole wander occurs, the effect of drill hole wander, the concept and design of the Rock Reammer, and a comparison of the Rock Reammer to present day mushroom shaped and retract style bits. In addition a direct comparison of drilling performance data for the new bit versus conventional bits is introduced.

Meeting Name

Proceedings of the 17th Annual Conference on Explosives and Blasting Technique


Mining Engineering

Document Type

Article - Conference proceedings

Document Version


File Type





© 1991 International Society of Explosives Engineers (ISEE), All rights reserved.

Publication Date

01 Jan 1991

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