As part of a regional search for uranium minerals and other radioactive minerals that may have formed within alluvial fan and palaeochannel sediments deposited south-east of and at some distance from the Mount Painter Block uraniferous basement outcrops, 35 open rotary mud holes (total penetration 16,852 feet) were drilled by Petromin close to the southern shore of Lake Frome, the holes being spaced about half-a-mile apart along selected present-day major drainage lines. Each drillhole penetrated the sedimentary cover of Recent, Tertiary and Mesozoic strata to approximately 500 feet depth, and was then geophysically logged with a wireline gamma ray probe run inside the drill string. No significant radioactivity was detected on the downhole logs, and only a few poorly developed porous or permeable Tertiary sedimentary units were encountered within a monotonous silty and clayey sequence containing slight amounts of carbonaceous material.