Structural and stratigraphical control of copper mineralisation at Mount Lyell

Copper ore at Mount Lyell occurs in quartz chlorite and quartz sericite schists derived from both Cambrian and Ordovician sediments. Mineralisation is centred at points of intersection of the longitudinal, deep-seated Lyell Shear, and cross-cutting E-W and NW faults. Within the mine area the Lyell Shear is expressed at and near the surface as a discontinuous, overturned, asymmetrical syncline with richer ore in the axial and the flat east limb positions, and with lower grade ore in the steep west limb. As yet by no means all of the flat east limb positions have been prospected, so that the field holds an exploration potential of more than ordinary interest.