A small graben indicated by regional geophysical data from an area north of Mount Woods was investigated for its Permian coal potential. A semi-detailed gravity survey of three NW-SE lines totalling 57 km at 200 m station spacing was conducted, and a pronounced gravity low was confirmed, but prevailing weather conditions made calibration ties impossible. Subsequent open hole rotary mud drilling and wireline geophysical logging of 23 stratigraphic holes (total 3438 m) failed to intersect economic coal seams, although most holes encountered carbonaceous Permian sediments. Out of the 10-hole first stage of drilling along gravity traverses, just one recognisable Permian coal seam only 0.8 m thick was met with, in hole MU3 at a depth of 81 m. Also, numerous thin patchy seams of Cretaceous brown coal were intersected in the overlying sandstones. A second gravity survey of 5 lines totalling 47.2 km was undertaken over the indicated graben depocentre, between drillholes MU6 and MU2, which outlined a larger gravity low likely to contain more coal. A second, 13-hole stage of drilling targeted this area and it showed that the gravity response is due to a thickening of the sedimentary pile, but also that only very thin (< 30 cm) coal seams were developed there. Overall it appears that the seams gradually improve in quality and thicken northwards, suggesting that the graben structure was not tectonically active and exerted no influence at the time of their deposition. Samples of both the Permian and Cretaceous coal seams were taken for chemical analysis plus petrography and palynological studies. Both ages of coal are sub-bituminous and of higher dry calorific value than either Leigh Creek or Lake Phillipson types. They are also lower in chloride content.