SYSTEMATIZATION OF OPERATING CONDITIONS FOR OPEN-PIT MOTOR TRANSPORT ACCORDING TO ENERGY CRITERION

Abstract

While operating modern motor vehicles in deep open pit mines, it is crucially important to develop methods and measures to evaluate the difficulty of mined rock transportation by open- pit dump trucks. It has been found out that currently there is no unified complex measure of transportation difficulty that could be used in technological evaluation of open-pit motor transport. Experimental and analytical researches carried out by the authors serve as a basis for the development of the transportation difficulty evaluation methods based on the calculation of the diesel fuel consumed by dump trucks per a load-haul-dump cycle and the actual load distance corrected in relation to conditional horizontal distance by means of the energy criterion. The coefficient of the haul distance complexity (μ) being the ratio of the corrected haul distance to the actual one is justified to be used as a criterion for the transportation difficulty evaluation. To correct a haul distance on the basis of the horizontal equivalents of the vertical rock mass movement, the calculated correlations have been obtained. It has been discovered
that the haul distance complexity is determined by the rate of slope, rolling resistance, tare-load ratio and load capacity utilization factor as well as empirical coefficients, taking into account the increase in the rolling resistance of empty dump trucks in motion, the increase in specific fuel consumption at a rated load of an engine of empty dump trucks moving along a horizontal road, fuel consumption of dump trucks in the brake-applied mode. The developed technique has provided the correlations for the calculation of the linear differential fuel allowance of dump trucks Cat-777D Cat-745S under operating
conditions of Nyurbinsk open-pit mine of «ALROSA» Diamond Company. Operating conditions for the open-pit motor transport have been systematized by means of the haul distance complexity criterion and divided into five classes (relatively easy, medium, complex, highly complex and extremely complex) with the haul distance complexity coefficient ranging from 1 to 3 and more. It has been found out that the current operating conditions of the motor transport in the majority of the diamond
mining pits of «ALROSA» refer to classes III-IV (complex and highly complex, μ = 2,0 ... 3,0). The introduction of all-wheel drive dump trucks during the cleaning-up stage will be accompanied by the transition to the operating conditions of Class V (extremely complex, μ = 5,0 ... 7,0). The developed methodological principles have been tested and are recommended for application in open pit motor transport. designing and operating