Improved Utilization of Underground Coal Reserves
Working reference on high extraction methods, from stooping and rib pillar extraction to auger, punch, longwall and backfilling, drawn from South African colliery experience for mine planners.
About 3.19 billion tons of coal now sits underground in pillars, growing by roughly 110 million tons a year under current bord and pillar practice. Pillars with a safety factor of about 1.8 or higher can be extracted successfully, and 1.5 is permissible in thin seams where the pillar width to height ratio exceeds 10.
R1500,00
Description
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