BROKEN Hill mining, like its metallurgy, has had its problems. Although the lode has been phenomenally rich, and now-although values have decreased-gives promise of a long period of production, there have been, and are, many difficulties of extraction to meet and solve. The ore-body is irregular in shape, and, except in a few places, does not lend itself to mechanical handling, and, therefore, to low working costs. It is of tremendous width in parts, has no standing strength, is friable and of even running character, and is enclosed within rotten walls. In the early days of the field, the ore which was being operated on consisted of carbonate and sulphate of lead, and practically all the minerals of silver, associated with kaolin and other decomposed material, and gave great trouble in mining. All the bad conditions were present, and before sufficient time had elapsed for the evolution of a system of work capable of dealing with them, some of the treasure was lost, and, considering the present difficulties of reaching it, perhaps irretrievably. The first method of stoping employed was on the open principle, involving the use of "clap-me-down" sets of local gum timber. This was found unsuitable, on account of the weakness of the ore and of the walls and the size of the deposits.