New mines are frequently located at altitudes above 3,000 meters (10,000 ft.). Drill selection must take the altitude effects into account, to insure high productivity and good bit life. In particular, compressors must be sized differently than for low altitude operation. A larger compressor is required to deliver adequate air to the bottom of the blasthole. Many drills in remote locations use diesel engines as the prime mover. Altitude effects on engine performance should also be considered. This paper discusses important factors pertaining to effective drill performance. The effect of altitude on these parameters is discussed. Bailing velocity and compressor capacity are addressed. Methodology for calculating proper compressor size is presented. Charts and tables providing design parameters are included. Effects of drill pipe wear are discussed and the relationship of altitude to engine horsepower is briefly discussed.
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