Holes drilled at a 30-degree angle rather than vertically, plus inadequate decking, contributed to the Aug. 21 subway station project excavation blast that broke several store windows on the east side ...
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To accomplish the job, MD&B is attacking in waves: Crews work their way across the hillside, drilling dozens of holes in the rock. Then, they pack those holes with 10,000-12,000 pounds of explosives ˆ ...
This 1917 Armstrong No. 25 churn drill derives its name from the up-and-down repetitive action of the drill stem and bit, not unlike an old-fashioned butter churn. Churn drills could produce from 20 ...
Mining equipment and services provider Sandvik Mining and Rock Technology has delivered and commissioned the first DR461i, now identified as the DR412i rotary blast hole drill, to the African ...
The Robbins H-100 was a high-production blast-hole drill employed by a number of surface-coal-mining companies in the Illinois Basin during the 1960s and 1970s. Starting with development work in 1960 ...
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