Abstract: Apparatus and method for determining the tensile load on a mine roof bolt, which is indicative of the support provided by the bolt. The device comprises a hammer for striking a roof bolt to produce a sound pulse, a microphone for picking up the sound pulse, and a sound comparator having a recorded sound or sounds whereby an operator can match the induced sound pulse with a recorded sound pulse to provide an indication of the tensile load on the roof bolt. The comparator may include a range of sounds, or may incorporate a variable speed function whereby the pitch of the recorded sound may be varied until the induced sound is matched. Comparison of the induced sound with the recorded sound provides an indication of the tensile load on the roof bolt.