A Fragmentation Experiment for in Situ Extraction.
D'andrea-DV; Dick-RA; Steckley-RC; Larson-WC
Solution Min Symp 103D AIME Ann Mtg 2/74 Am Inst Min Metall & Petrol Eng 1974 Feb :148-161
A fragmentation experiment was performed in cooperation with Duval Corp. in a porphyry-copper-molybdenum deposit near the sierrita pit south of Tucson, Arizona. A 10-hole test blast was detonated to establish relationships between blasthole spacing and the resulting fragmentation. Blastholes were 9 in. In diameter and 110 feet deep. The 10 blastholes contained a total of 17,400 lb of aluminized slurry blasting agent in 50-ft columns with 60 ft. of stemming. Blasthole spacings of 25, 20, and 15 ft were tested. Diamond drill core examinations was the primary method used to determine the condition of the rock before and after blasting. Topographic surveys were used to measure the rock swell produced by the blast and a fragment size distribution was obtained for the rubblized material on the surface. The rubble zone at the surface was ideal for in situ leaching. Fragmentation to depths of 110 ft was excellent from the 15- to 20-ft blasthole spacing patterns. Good breakage was also produced by the 25-ft pattern.
Solution Min. Symp., 103D AIME Ann Mtg., 2/74; Am. Inst. Min., Metall. & Petrol. Eng., pp 148-161