Browsing by Author "Salama, Abubakary Juma"

Now showing 1 - 7 of 7
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    Alternative Process Flow for Underground Mining Operations: Analysis of Conceptual Transport Methods Using Discrete Event Simulation
    (MDPI AG, Basel, Switzerland, 2016-06-30) Greberg, Jenny; Salama, Abubakary Juma; Gustafson, Anna; Skawina, Bartłomiej
    As the near surface deposits are being mined out, underground mines will increasingly operate at greater depths. This will increase the challenges related to transporting materials from deeper levels to the surface. For many years, the ore and waste transportation from most deep underground mines has depended on some or all of the following: truck haulage, conveyor belts, shafts, rails, and ore pass systems. In sub-level caving, and where ore passes are used, trains operating on the main lower level transport the ore from ore passes to a crusher, for subsequent hoisting to the surface through the shaft system. In many mines, the use of the ore pass system has led to several problems related to the ore pass availability, causing production disturbances and incurred cost and time for ore pass rehabilitation. These production disturbances have an impact on the mining activities since they increase the operational costs, and lower the mine throughput. A continued dependency on rock mass transportation using ore passes will generate high capital costs for various supporting structures such as rail tracks, shaft extensions, and crushers for every new main level. This study was conducted at an existing underground mine and analyzed the transport of ore from loading areas at the lower levels up to the existing shaft points using trucks without employing ore passes. The results show that, when the costs of extending ore passes to lower levels become too great or ore passes cannot be used for production, haul trucks can be a feasible alternative method for transport of ore and waste up the ramp to the existing crusher located at the previous main level. The use of trucks will avoid installing infrastructure at the next main level and extending the ore passes to lower levels, hence reducing costs.
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    Analyzing energy consumption and gas emissions of loading equipment in underground mining
    (Canadian Institute of Mining, Metallurgy and Petroleum., 2015) Salama, Abubakary Juma; Greberg, Jenny; Skawina, Bartlomiej; Gustafson, Anna
    In an environment of rising energy prices and mining at greater depths, cost-efficient loading and hauling equipment is essential. Conducted at an underground mining operation, this study analyzes the energy consumption and gas emissions of diesel and electric load-haul-dump machines (LHDs) with similar bucket capacities. Based on energy prices from the first quarter of 2014, results of discrete event simulation show that energy costs for diesel and electric LHDs are US$0.24/t and US$0.07/t, respectively. Also, diesel LHDs emit 2.68 kg CO2 per litre of diesel fuel, whereas using electric machines reduces the need for ventilation to mitigate engine heat and emissions and reduces energy costs.
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    Evaluation of the impact of commodity price change on mine plan of underground mining
    (Elsevier, 2015-04-15) Salama, Abubakary Juma; Nehring, Micah; Greberg, Jenny
    Fluctuations in commodity prices should influence mining operations to continually update and adjust their mine plans in order to capture additional value under new market conditions. One of the adjustments is the change in production sequencing. This paper seeks to present a method for quantifying the net present value (NPV) that may be directly attributed to the change in commodity prices. The evaluation is conducted across ten copper price scenarios. Discrete event simulation combined with mixed integer programming was used to attain a viable production strategy and to generate optimal mine plans. The analysis indicates that an increase in prices results in an increased in the NPV from $96.57M to $755.65M. In an environment where mining operations must be striving to gain as much value as possible from the rights to exploit a finite resource, it is not appropriate to keep operating under the same mine plan if commodity prices alter during the course of operations.
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    Mechanical Excavation and Drilling and Blasting – A Comparison Using Discrete Event Simulation
    (Springer International Publishing, 2014) Skawina, Bartłomiej; Greberg, Jenny; Salama, Abubakary Juma; Schunnesson, Håkan
    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.
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    Operating value optimisation using simulation and mixed integer programming
    (Taylor & Francis, 2013-04-19) Salama, Abubakary Juma; Nehring, Micah; Greberg, Jenny
    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 3000m 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.
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    Optimization of Truck-Loader haulage system in an underground mine: A simulation approach using SimMine
    (MassMin 2012 : 6th International Conference & Exhibition on Mass Mining, Sudbury, In. Canada, June 10-14 2012, 2012-11-09) Salama, Abubakary Juma; Greberg, Jenny
    working face and transporting it to the dumping point where it is reloaded into trucks for further transportation. In some cases, trucks can be loaded directly at the working face or at a dumping point. Due to a limited size of the drifts and the ramps used in transporting material, the size of the haulage equipment is an important factor to consider when seeking to optimize the haulage system. This paper studies the haulage system of a mine which operates a fleet of three Load-Haul-Dump (LHD) machines and three dump trucks, using SimMine simulation software. Its aim is to evaluate the effect of increasing the number of trucks on the overall mine throughput. The results indicated that the capacity of the existing loading equipment does not match the number of trucks; this affects the haulage system and the mine production. The study resulted in the recommendation to increase the fleet of dump trucks.
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    The use of discrete event simulation for underground haulage mining equipment selection
    (Inderscience publishers, 2014) Salama, Abubakary Juma; Greberg, Jenny; Schunnesson, Håkan
    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.