Koste-aspekte by terugvulmynbou

Abstract

Due to the rising costs and lower gold price experienced the last couple of years, the gold mining industry was forced to look at alternative mining methods. A large number of different methods were evaluated but the two most prominent were Trackless mining and Backfill mining. Trackless mining is a process where, as the name indicates, no rails are used. The traditional method of coco-pans pulled by a locomotive to extract the ore from the mine is replaced by mechanical equipment. This equipment is self powered and has wheels to enable them to move freely without the limitations of rails. Backfill mining is the process where the waste out of the recovery process is used to fill the areas that has been mined out. When the waste leaves the gold and uranium plant it goes through an additional recovery process. At this stage the waste has a very low gold content and can be used to fill the mined-out areas. The waste, in a slimish form, is pumped to the section underground where the backfilling is taking place. The complexity of the method created many costing problems for the mining industry. Vaal Reefs Mining and Exploration Co. (Pty) Ltd approached me to identify the problem areas in backfill mining and to make the necessary recommendations in order to solve the problems. For this purpose the whole backfill process was broken down into different cost centres. They were identified as: - from the gold and uranium plant to the backfill recovery plant, - the backfill recovery plant, - from the backfill recovery plant to the backfill control station at the mine, - from the backfill control station to the work area where the actual backfilling is done.

Every cost centre was evaluated separately and problem areas were identified. The main problem areas are: - No accrual is made for the income received from the backfill recovery plant and is not written off against the cost of the plant. - Two different methods can exist in the backfill recovery plant: n The first where all the slime goes through the backfill recovery plant regardless if it will be used in the backfill process or not. The problem that exists with the first method is that the slime, that is treated to be used in backfill process, carries all the costs and no costs are carried by slime that is pumped to_the slime dams. To solve the problem, joint costs must be identified. This cost will ten be allocated, - based on a percentage base to the different types of slime. The percentage must be determined by deviding the tons of slime used in the backfill process over the total tons of slime treated in the backfill recovery plant. ...