New Instrumentation for Roof Bolt Load Measurement

The disadvantages of using torque readings to estimate point-anchored bolt loads have long made it desirable to find an alternate technique that would provide high accuracy at low cost per bolt and not disturb the anchorage. Bureau of Mines research efforts to use electronic means to meet these goals are detailed. A brief history of the techniques considered is presented. Details of the electronic and mechanical development needed to apply this technology to mine roof bolts are presented. Laboratory and field results are illustrated. Current applications potential applications, and limitations are discussed. An instrument that at the present stage of research appears to have the potential to make the desired measurement is discussed.