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Blasting Tests in a Porphyry Copper Deposit in Preparation for in Situ Extraction.

Authors
Steckley-RC; Larson-WC; D'andrea-DV
Source
NTIS: PB 247 199 :47 pages
Link
NIOSHTIC No.
10007755
Abstract
The Bureau of Mines performed a fragmentation experiment in cooperation with Duval Corp. In a porphyry copper-molybdenum deposit near the Sierrita Pit south of Tucson, Arizona. This experiment evaluated the fragmentation created in a 10-hole test blast having blasthole spacings of 25, 20, and 15 feet. The 10 blastholes were 9 inches in diameter and contained a total of 17,400 pounds of aluminized slurry blasting agent in 50-foot columns with 60 feet of stemming. Diamond drill core examination was the primary method used to determine the condition of the rock before and after blasting. These core examinations included study of length recovery, rock quality designation, weight recovery, and size distribution. Topographic surveys were used to measure the rock swell produced by the blast, and a fragment size distribution was obtained for the broken material on the surface. Fragmentation to depths of 110 feet was excellent from the 15 to 20-foot blasthole spacing patterns. Good breakage was also produced by the 25-foot pattern although the effects of the blast were not so obvious. In situ leaching tests were not conducted. However, based only on size consideration, all three blasting patterns produced adequate breakage for successful leaching.
Publication Date
19750101
Document Type
IH; Report of Investigation;
Fiscal Year
1975
NTIS Accession No.
PB-247199
NTIS Price
A04
Identifying No.
RI 8070
NIOSH Division
TCRC;
Source Name
NTIS: PB 247 199
State
AZ;
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