Improving Performance of Mining Equipment Through Enhancement of Speed Factor: A Case Study

The ever increasing demand for minerals has forced the surface mines to consistently upgrade the mechanization, for extracting minerals and removing overburden (OB), as well. Also, loading and hauling machineries are highly capital intensive equipments to procure, operate and maintain in surface mining operation. These machineries perform tens of thousands of cycles annually. Therefore, a small improvement in their speed factor will definitely have a significant effect on their production and productivity. Speed factor is the ratio of the planned cycle time of the equipment to the actual cycle time. For an idealized situation, the speed factor should be equal to 1. The low range of speed factor can be defined as the increase in cycle time of operation and decrease in production of this equipment. In the case study mine, speed factor of dragline operation was computed as 0.8222 which amounts to a loss of 1039 work hours per year or an annual loss of 50,531 cycles of operation which is an equivalent loss of 844221 m3 in output. Therefore, a small improvement in speed factor will definitely have a significant effect on its performance and production. As such, it is imperative to critically analyze the cycle time operation of this machine in order to enhance the speed factor, overall effectiveness and production. In this light, the present paper is an endeavour to critically analyze actual cycle time of dragline operation. In this regard, field observations for cycle time of dragline operation were precisely recorded on the basis of time and motion study. This was done by capturing real-time motion pictures of dragline operation, under normal operating conditions, by robust field camera installed with a precise in-built watch. The influence of degree of fragmentation on the cycle time was also critically evaluated by image analysis of the blasted muck pile. Descriptive statistics of the cycle time data reveal that unloading time is more or less constant; also there is not much variation in swing time segment. But the digging time segment exhibits significant variations which are affected by numerous field conditions such as collar oversize of blasted rock and balancing diagram of cut geometries.