In-the-hole drilling at Heath Steele Mines Limited

CIM Bulletin, Vol. 72, No. 810, 1979

ERROL LADNER, Mine Engineer, Heath Steele Mines Limited, Newcastle, N.B.

The application of large-diameter bore holes in underground operations at Heath Steele was first tried in February, 1975. Since that time, 90,000 feet of 6-1/2-inch holes have been drilled, primarily in open blasthole sloping, for a total of 1.4 million tons, 37% of underground production.This paper deals with a review of drilling with conventional percussion longhole drills, a practice which is still utilized at Heath Steele, and the changeover to accommodate the use of larger blastholes in underground operations. The discussion will include layouts for 2-inch-diameter blasthole slope blocks, 6-inch-diameter slope blocks, trials for I.T.H. (in-the-hole) slope rooms, and drill patterns, drilling and performance.The complexity involved in the development, drilling and blasting of 2-inch blastholes is overcome by the over-all simplicity of drilling and blasting in I. T.H. slopes. This has made the practice of open blasthole sloping more economical and efficient. The future indicates an increase in the company's I.T.H. program. Investigations are being undertaken regarding longer holes to decrease development costs. A VCR slope is also being developed for trial.

Keywords: Underground mining, Drilling, In-the-hole drilling, Heath Steele Mines, Stoping, Blasthole Stoping, Compressors, Bits.