Ultrasonic logging instrument for shaft sinking by drilling

Shaft sinking by drilling is widely used in mining, construction and coal industry. Measuring the shaft borehole accurately, is of great importance to the quality in these projects among other factors. This paper proposes a novel design and implementation of ultrasonic logging instrument for shaft sinking by drilling (ULISSD). Design of the ultrasonic ranging module, depth module and the module for downhole orientation, as well as the borehole radius measurement algorithm are explained and illustrated. This paper also demonstrates an experimental application of ULISSD, which shows that, compared with other similar instruments, ULISSD is able to measure accurately borehole shaft radius wider diameters (3–12 m) at deeper vertical sections (maximum 1000 m) in slurry with higher gravity (≤ 1.22).