Prediction of blast fragmentation of underground stopes for in situ leaching

Conference · Sat Dec 31 04:00:00 EST 1994

OSTI ID:398332

Stagg, M S; Otterness, R E ^[1]; Djahanguiri, F ^[2]

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1. Bureau of Mines, Minneapolis, MN (United States). Twin Cities Research Center
2. Bureau of Mines, Denver, CO (United States). Denver Research Center

The US Bureau of Mines (USBM) evaluated empirical equations that predict fragmentation from underground stope rounds. Controlled blasting is necessary for creating leaching stopes that maximize the recovery and minimize backbreak of the perimeter wall. This paper presents the fragmentation results from one of the three drop-raise blasts used to develop a reduced-scale cylindrical stope, 1.8 m in diameter and 6 m in height. The stope is located in the Colorado School of Mines Experimental Mine (Edgar Mine) in Idaho Springs, Colorado. This stope is part of a USBM research effort to determine the feasibility of incorporating in situ leaching of rubblized stopes into active underground metal and nonmetal mines. All the material from the first blast, 14 mtons was sieved. The resulting distribution was compared to the distribution predicted from empirical equations. The best fit was found with a USBM equation developed from over 50 sieved, reduced-scale (1- to 2-m) high wall blasts. Modifications to the equations were made to account for the observed differences due to breakout angle, shot geometry, initiation timing, decoupling, rock fracture toughness and explosive energy.

• OSTI ID: 398332
• Report Number(s): CONF-9401127--
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
DISTRIBUTION
EXPLOSIVE FRACTURING
FORECASTING
FRAGMENTATION
PARTICLE SIZE
RESERVOIR ROCK
SOLUTION MINING
UNDERGROUND MINING