Roof support faults

Mines could theoretically improve roof support, using the same methods of support as a tunnel that might be expected to remain stable for hundreds of years. But mines are constantly changing environments, and it would be eco-nt)mically unfeasible to invest resources in permanent support structures. Mines frequently add additional supports if there is any evidence of instability. But roof support is as much an art as a science, particularly when mines encounter unexpected faults (large cracks of discontinuities) in the rock strata. 

All rock contains faults. Faults can range from inches to hundreds of feet vertically and from inches to miles horizontally. These faults are particularly dangerous because they are, by definition, present in the rock before mining starts, but mines may not know a fault exists until they have committed to a mining plan. At other times, nearby mines know about faults but do not communicate information to other worksites. Mining practices can also disturb the.se faults, causing a massive roof fell. If engineers know the layout of faults, they can plan a roof support system in advance that will stabilize the strata... 

Despite this dynamic uncertainty, engineers must construct plans to control risk and predict hazard in the everyday working operations of the mines. Roof-support engineers, for example, must map underground faults, determine stress and load levels, and construct plans that outline the minimum support methods and requirements for each section of the mine. These support requirements include a broad plan for overall roof support as well as site-specific rules for pillar width and additional support. But engineers must also be prepared to respond to change. 

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