High-quality medium-volatile bituminous coking coal from the Orion, Pollux, and Castor seams from the upper Permian Rangal Coal Measures (Australia) is one of the lowest ash, prime hard coking coal blends produced in Australia, and also low in sulphur and produces very strong coke when carbonized alone and in blends. Attempts to predict coking properties of the coals from petrographic data produced predicted coke stabilities that were significantly lower than those determined from coke tests. The study characterized the Curragh coals in terms of physical, chemical, and petrographic characteristics and strength testing. A series of suggested techniques for improving predictions of coke strength from petrographic data were examined and a new and improved technique was developed for the Curragh coals.