Rationale for the parameters of steeply inclined ramps of kimberlite pits deep horizons exposing

Abstract

Research aim is to substantiate optimal road grade when operating 4WD dump trucks and to develop analytical method of calculating the volume of additional spacing of non-mining slopes of an opencast from motor transport lanes placement when exposing deep kimberlite pits with spiral routes. Research relevance. Transition to steeply inclined ramps and 4WD dump trucks is a basic trend in improving the efficiency of deep kimberlite pits mining. In this regard, the issues of substantiating road grades and developing the method of calculating the volume of additional spacing of non-mining slopes of an opencast from motor transport lanes placement are becoming increasingly relevant. Research methodology. When substantiating road grade for 4WD dump trucks the physical principle of minimal action was used as well as dump trucks tractive and dynamic, braking and fuel conditions together with some experimental data. A new notion of “specific action” has been introduced. Optimal grade by the criterion of specific action complies with minimum energy for mined rock lifting under maximum hauling capacity. The elaborated analytical method of calculating the volume of additional spacing of non-mining slopes of an opencast is characterized by the integrated record of basic process parameters of uncovering. Graphical method of finding the angle of the non-mining slope has been proposed being a controlled parameter at uncovering with steeply pitching ramps. Results. It has been determined that optimal grade value by physical criterion of specific action are determined by the dependences between transmission efficiency, road speed and specific fuel consumption by 4WD dump trucks and the total traction resistance in slopes. For CAT-745С dump trucks optimal values slopes for macadamized roads within the range of 0.18–0.24. The patterns of basic mine engineering factors influence on the volume of additional spacing of slopes from motor transport lanes placement. Major effect on the volume of flattening is brought about by the depth of the pit, spiral ramps grade and ore body thickness. So, the introduction of steeply inclined uncovering is primarily recommended in kimberlite open pits when mining thin ore bodies. Scope of results. The obtained results may be applied in deep kimberlite open pits design and operation when introducing 4WD dump trucks. The results may also be applied in ore open pits when uncovering deep horizons by spiral ramps.