Instrumentation for Load and Convergence Measurements in Mines

Any artificial excavation in the rock strata disturbs the equilibrium of stresses. These stresses try to readjust to bring about an equilibrium around the opening. The readjustment of these stresses may be achieved either by filling the cavity or may be temporarily controlled by different artificial support. The parameters of these artificial supports can only be determined by thorough investigation of the stresses. In the past trial and error methods were used for determining these parameters which are no more acceptable because the efficiency and safety of the underground working units is largely dependent upon the extent to which the pressure and the movement of the strata surrounding the mine excavation can be controlled. Modern measuring instruments make it possible to determine the exact values of these parameters. Based on these observations, modern types of support systems are being developed to suit the particular requirements. During these observations, different types of load and convergence measuring techniques have been developed and used. A short review of these developments is given in this paper. The instruments developed by the authors at the Central Mining Research Station, Dhanbad, for these measurements are also described