This report presents the results of the performance of arrangments of drag picks and disc cutters cutting through lower chalk during the tunnelling trials at Chinnor, Oxfordshire. Power changes produced by varying the cutter tool type and arrangement on the machine head were recorded and plotted against cutter tool and machine variables. The depth of cut and cutting to relief were fiound to be the major influences on the efficiency of cutting with both types of cutters. The implications of the trials are that cutter arrangments should be adaptable to rock conditions and that the fitting of simple instrumentation to record the power used in cutting would enable the best operational depth of cut to be identified.