A geological investigation of the Yeuralba mineral field was undertaken by the Bureau of Mineral resources as part of the field activities for the 1952 field season. Actual field work occupied five weeks in August and September. Most of this time was devoted to sampling individual greisen occurrences. In addition, a geological map of Yeuralba and the surrounding area was prepared on a scale of 1:25,000. Sandstones and tuffaceous sandstones of Lower Proterozoic age have been folded and intruded by porphyry, epidiorite, and granite, in the Yeuralba area. The granite intrusion was followed by a strong tensional movement and a regional system of black faults and strong joints was developed. Lower Cretaceous sandstone and porcellanite unconformably overlie the igneous rocks and Lower Proterozoic metamorphics. The granite has been hydrothermally altered to a marked degree along these fractures. Tin, tungsten, gold and bismuth mineralization is associated with greisen, tourmalite, topazite, and other alteration products of the granite. Cassiterite-bearing tourmalites and assiterite-wolframite-gold-bearing topazites and tourmalites occur within the granites mass and wolframite-scheelite-bismuth-bearing greisens at the contact between the granite and the sediments. Bulk sampling and preliminary grab sampling of a number of these bodies indicates that several of the bodies should be tested in a more detailed manner, to determine whether they will bulk at a grade which would permit economic mining of the deposits.