ABSTRACT
Improvement of economy has always been the aim of mining companies and manufacturers of open pit equipment. This target requires intensive studies to find the optimum mining system and systematic developments of existing machines to gain a higher output without increase of investments. When analyzing the spreaders from about 1970 onwards, it becomes clear that the favorable capacity/weight ratios are mainly associated with compact spreaders and the less favorable values with C-frame spreaders. The effective annual capacities as well as the necessary capital investments have been estimated. The specific capital investment is defined as capital investments relatives to the annual capacity and has been plotted for both systems. To optimize the specific capital investments of a system with compact machines, the influence of bucket wheel outreach on block dimensions and excavator efficiency is investigated. An increase in size of the bucket wheel excavator alone in a system of compact machines will have a very positive effect on the effective capacity.
