The application of TSIM in defining sills in coal seams: A case study at Coppabella Mine

Thiel Surface Impedance Method (TSIM) is a surface electromagnetic device that uses VLF radio waves at a single frequency to measure apparent resistivity changes in the subsurface. The technique allows the interpreter to accurately delineate known geological features and identify previously unrecognised discontinuities. The aim of the TSIM survey at Coppabella Mine was to determine areas of heavy intrusion in the coal. The survey was conducted in a grid pattern with 16 lines and a total line length of 3,600 m. TSIM has been successfully used at Coppabella Mine to identify areas of low apparent resistivity occurring where intrusion is expected.