Railway ballast was sought from amphibolite of the Kanmantoo Group of Cambrian age which subcrops on a bedrock ridge in the Murray Basin near Tailem Bend. A surface sample of amphibolite returned low Los Angelese Abrasion and Sodium Sulphate Soundness losses of 12 per cent and 0.5 per cent respectively. No deleterious minerals were observed. Forty-two rotary air drill holes and five seismic traverses defined a target area of 2650 square metres. Overburden, averaging 2.9 metres in thickness comprised Lexton Sands, Blanchetown Clay, calcrete of the Bakara Soil and Molineaux Sand. Four diamond core drillholes intersected a sequence of amphibolites and quartzites suitable for ballast with interbeds of weathered schist which would be deleterious in crushed rock. The high proportion of weathered schist is unacceptable for railway ballast. Before the site is abandoned, trenching is recommended to examine the lateral extension of a favourable zone 18 metres wide intersected in diamond core hole DT1.