Investigations of the Lyndhurst Diapir were started after its reservation in January 1966. Early work consisted of the collection and analysis of orientation and reconnaissance stream sediment (513 samples) and soil samples (2016 samples). The distribution of high copper assay results warranted concentration of effort upon the south-central part of the area, where extensive geochemical and geophysical anomalies coincide with mineralised shale horizons. An initial inclined diamond hole drilled to 280.9 feet total depth at the West Mount Lyndhurst prospect intersected minor but encouraging concentrations of copper, as part of an investigation of SP and IP anomalies originating from below an old miner's trench exposing disseminated mineralisation.