Structural analysis of the broken hill block : B. E. Hobbs ∗ N. Archibald, ∗ M. A. Etheridget † and V. J. Wall, ∗∗Department of Earth Sciences, Monash University, Clayton, Victoria, Australia, 3168, †Bureau of Mineral Resources, P.O. Box 378, Canberra, A.C.T., Australia, 2601