Justification of Optimal Gradient of Steeply Inclined Ramps for All-Wheel Drive Dump Trucks Used in Diamond Deposit Completion

At present, the design depth of open-cast diamond (kimberlite) mines is increasing through introduction of advanced technologies and new mining and transportation equipment. In 2008-2012 the Yakutniproalmaz Institute and the Institute of Mining developed scientific and methodological principles and design solutions for development of the Udachny and Botuobinsky deep open pit mines using steeply inclined ramps and the CAT-740B articulated dump trucks with the capacity of 39.5 tons. Research was conducted to determine the rational slope for articulated dump trucks in the Udachny open pit and to develop guidelines for safe operation of such dump trucks on steep inclines. The performed experiments demonstrated the ability of articulated dump trucks to safely haul rocks with loads that were close to the nominal capacity using ramps with the slope gradients up to 24% in various weather conditions. In spite of a sufficiently large number of studies on justification of parameters of developing deep open pit levels, many questions still require additional research. This is primarily explained by the limited experience of operating articulated dump trucks in Russian deep open pit mines. In this context, the issue of justifying the optimal slope gradients for all-wheel drive models of motor vehicles remains relevant. The authors of the article have analyzed the existing normative documents and methods to determine the rate of longitudinal slopes. As the result of the study, the physical criterion of the least action is proposed as the optimization criterion for the slope gradients of the in-pit roads when operating all-wheel drive dump trucks.