Abubakary Salama

The use of discrete event simulation for underground haulage mining equipment selection

The selection of equipment for haulage in underground mines is a challenge due to its impact on both production rates and costs. The selected equipment should create an optimal match for the complete system and the point when equipment is to be added or replaced needs to be identified before the change is made. The use of discrete event simulation to compare two different haulage units of different size with the aim of improving production is presented. The feasibility of the production targets was also analysed. The result shows that, the smaller unit improves the average production from 52% to 75% while the bigger unit improves to 83% of the planned production target. This shows that the production will rise by 8% when smaller units are replaced by bigger units. This may need to be justified financially as the costs associated with changing the truck size might be recuperated by extra production gained. Furthermore, the study showed that current production targets were not feasible under the given circumstances.

Operating value optimization using simulation and mixed integer programming

Mining operations around the world will increasingly need to operate at greater depths. This significantly influences the complexity of ore extraction and ore transportation to the surface. The increase in mine depth leads to increases in haulage distance from mine areas to the mine surface. This results in an increase in energy costs to haul material further. Due to the increasing cost of future operations, the choice of the haulage method becomes an important factor in the optimisation of the mine plan. The haulage process is one of the most energy intensive activities in a mining operation, and thus, one of the main contributors to energy cost. This paper presents the comparison of the operating values of the mine plans at depth levels of 1000, 2000 and 3000 m for diesel and electric trucks, shaft and belt conveyor haulage systems for the current and a predicted future energy price scenario. The aim is to analyse the impact of energy requirements associated with each haulage method, as well as the use of alternative sequencing techniques as mine depth increases. This study is carried out using a combination of discrete event simulation and mixed integer programming (MIP) as a tool to improve decision-making in the process of generating and optimising the mine plans. Results show that energy cost increases across each haulage method at both current and future energy prices, with increasing depth. This study thus provides a broad and up to date analysis of the impact on operating values that may be experienced with the use of the main haulage systems available at present. Also, the study shows how the combination of discrete event simulation and MIP generates a good tool for decision support.

Mechanical Excavation and Drilling and Blasting – A Comparison Using Discrete Event Simulation

Mine development is often a bottleneck in mining operations and is strongly influenced by the choice of excavation method. In this paper, the two well-recognized methods, conventional drill and blast and mechanical excavation, are compared and discussed. The former method is the continuation of a long tradition in mining, while the latter method started to be used in 1960s, when mechanical excavators such as roadheaders, continuous miners or tunnel boring machines were developed. The rate at which the tunnel advances is one of the most important factors for mine development. By evaluating and selecting the right technique, the speed and effectiveness of the development could be improved. This paper aims to estimate and compare the advancement rate between the mechanical excavator and drill and blast method using simulation with AutoMod. This study has been done for one of Boliden Mineral AB’s mines in Sweden. For the drill and blast method, the study shows increased performance for two simultaneously drilled tunnels when compared with a single one. Furthermore, the simulation runs have estimated the total tunnel development times for the specified development lengths. The study is concluded by sketching an interesting picture of mine development using the mechanical excavator.