In-pit crushing and conveying as an alternative to an all truck system in open pit mines

The material transport system in an open pit mine significantly affects the capital and operating costs. All truck haulage is the most common and is a reliable and flexible transport system. On the other hand, this system is very expensive and can cost up to 50% of total mining costs. Its cost is continuously increasing due to the inflation of the fuel, tire, and labour expenditures. In-pit crushing and conveying is an alternative transport system which requires a higher initial investment but gives substantial savings in operating costs. An evaluation of the all truck system versus the in-pit crushing and conveying system has been performed by means of a simulation of both transport systems in the same mine model. Results of the simulation and the data obtained from the feasibility studies provided input for an economic comparison of the alternative transport systems. A cash flow analysis showed that the in-pit crushing and conveying system was competitive with the all truck system, giving a payback within four years and resulting in total costs over 30% lower than those of an all truck system. Three computer programs, written by the author, have been used to analyse the mine model: (1) Open Pit Simulation Program - to model a hypothetical mine and simulate its haulage operation over the mine life, (2) Off-Highway Truck Simulation Program - to simulate the truck haulage on average annual routes in terms of the operating time and fuel consumption for the estimation of the truck fleet size and the fuel cost, (3) Cash Flow Analysis Calculation Program - to compare costs of the alternative transport systems over the whole period of a mine life.