Date of Graduation

1995

Document Type

Dissertation/Thesis

Abstract

Roof bolting is now the primary means of roof support in mines. Further, the beam building mechanism is now believed to be the primary mechanism by which roof bolts work. This statement particularly holds true for laminated roof strata. With beam building, the roof strata is reinforced by the installed tension of the roof bolt to a point where it will resist the effects of both vertical and horizontal stresses. Despite all the advances that have been made in the area of roof control, no precise criteria has been formulated to determine what combination of bolt length and tension is required to control a given roof condition. This dissertation researches these two parameters. Nine extensive instrumented underground test areas were implemented in an active longwall gate road section. The test areas were monitored from the time of initial development until the longwall had mined outby the test area. Data analysis indicates high bolt tension and reduced length can provide a much more stable roof condition. Computer modeling, through use of the ANSYS Finite Element Analysis program, validated the test data. Once the validation process was completed, the design criteria in terms of bolt length and tension was determined.

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