The Effect of Important Fragmented Rock Properties on the Penetration Rate of Loader Bucket

Loading and haulage costs make up the majority of the expenses—almost half of its total costs at many mines. At many mines, loading and haulage costs make up the majority of the expenses—almost half of its total costs, in fact. Many researchers believe that the properties of fragmented rock are one of the most important factors that affect the productivity of loading machines. The purpose of this paper is to study the effects of fragmented rock properties on the penetration rate of a loader’s bucket as one of the parameters of loading productivity. The study will be done using a simulated loader in the laboratory. For the study, 25 samples of fragmented rock with previously defined Rosin–Rammler’s size-distribution function, including the defined mean particle size (d50) and uniformity index (n), were built. Then, bulk-specific gravity and angle of repose of the samples were measured using standard laboratory tests. The relation of n and d50 and the measured properties of the samples with each other and with the penetration rate of the loader’s bucket were analysed. The results showed high correlation between pre-determined size distribution parameters and the measured properties of fragmented rock, including bulk-specific gravity and angle of repose. Also, the penetration rate is inversely correlated to the uniformity index, the angle of repose, and consequently, internal friction angle. And, it is in direct correlation with the mean particle size of the fragmented rocks and bulk specific gravity. It is obvious from the results that uniformity has more effect on the penetration rate than the mean particle size does.