Effects on the final intensity of input forces in longbolts installed at the mining operation 2 area, OKD, inc

Abstract

In the deep coal mines of OKD, Inc., both bolts and long bolts of different designs are used for the rock massif and steel arch support reinforcement. Continuous measurement of forces in 6 strand bolts and 1 cable bolt (long bolts, generally) was carried out during the trial operation of the modified Room and pillar mining method at Mining operation 2, site North, OKD, Inc. Hydraulic dynamometers were installed on these long bolts and a monitoring of forces took place throughout the life-time period of the mining panel No. V. From this measurement, a knowledge of their different load behavior with respect to the input stress parameters was obtained. The input intensity of the force applied to the bolting elements is burdened by losses of various kinds. The subject of the article is a description and analysis of the intensity of the initial stressing force applied to individual long bolts (with a threaded clamping bush or wedge barrel) and quantization of short-term stress losses with a description and analysis of these.