Academic literature on the topic 'In-Pit Crushing and Conveying'

In-pit crushing and conveying (IPCC) systems have drawn attention to the modern mining industry due to the numerous benefits than conventional truck-and-shovel systems. However, the implementation of the IPCC system can reduce mining flexibility and introduce additional mining sequence requirements. This paper investigates the long-term production scheduling and the crusher relocation plan of open-pit mines using a semi-mobile IPCC system and high-angle conveyor. A series of candidate high-angle conveyor locations is generated around the pit limit, with a crusher located along each conveyor line. Each conveyor location is solved independently by an integer linear programming model for making production scheduling and crushing station decisions, aiming to maximize the net present value (NPV) considering the material handling and crushing station relocation costs. The production schedule with the highest NPV and the associated conveyor and crusher location is considered the optimum or near-optimum solution.

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.
Applied Science, Faculty of
Mining Engineering, Keevil Institute of
Graduate

As ore grades decline, waste rock to ore ratios increase and mines become progressively deeper mining operations face challenges in more complex scenarios. Today´s predominant means of material transport in hard-rock surface mines are conventional mining trucks however despite rationalisation efforts material transportation cost increased significantly over the last decades and currently reach up to 60% of overall mining. Thus, considerations and efforts to reduce overall mining costs, promise highest success when focusing on the development of more economic material transport methods. Semi-mobile in-pit crusher and conveyor (SMIPCC) systems represent a viable, safer and less fossil fuel dependent alternative however its viability is still highly argued as inadequate methods for the long term projection of system capacity leads to high uncertainty and consequently higher risk. Therefore, the objective of this thesis is to develop a structured method for the determination of In-pit crusher and conveyor SMIPCC system that incorporates the random behaviour of system elements and their interaction. The method is based on a structured time usage model specific to SMIPCC system supported by a stochastic simulation. The developed method is used in a case study based on a hypothetical mine environment to analyse the system behaviour with regards to time usage model component, system capacity, and cost as a function of truck quantity and stockpile capacity. Furthermore, a comparison between a conventional truck & shovel system and SMIPCC system is provided. Results show that the capacity of a SMIPCC system reaches an optimum in terms of cost per tonne, which is 24% (22 cents per tonne) lower than a truck and shovel system. In addition, the developed method is found to be effective in providing a significantly higher level of information, which can be used in the mining industry to accurately project the economic viability of implementing a SMIPCC system.

Magíster en Minería
La minería a cielo abierto se caracteriza por sus grandes volúmenes de producción, los cuales hacen posible la operación de minas con bajas leyes, altos costos de inversión, crecientes costos operativos y la reducción de la productividad debido a la profundidad de los rajos; a todo esto se suma la complejidad para administrar grandes flotas de camiones de alto tonelaje. Es por ello que en la actualidad se hace determinante el uso de tecnologías correctas en las actividades de mayor incidencia en el costo mina. El principal objetivo de este trabajo es el desarrollo de una metodología adaptable al mundo minero polimetálico usando In-Pit Crushing and Conveyors (IPCC), ya que ofrece diversas configuraciones para su aplicabilidad, convirtiéndola en una opción atractiva. Se inició con un estudio pormenorizado del transporte de materiales, sintetizando sus variables más influyentes, como es el costo del combustible. Posteriormente se avaluó la evolución del costo mina en función de la profundidad. Ésta fue desarrollada en base a simulación del sistema tradicional de carguío y transporte, considerando el consumo de combustible para la flota de camiones. Luego para el modelamiento del costo mina se partió de la premisa que el costo de combustible representa un 25% del costo mina, para proseguir con la optimización, agentamiento y evaluación de cada escenario. Dentro de los resultados obtenidos se puede apreciar variaciones en el material a remover tanto en mineral como en desmonte. El costo de capital mayor del IPCC es abatido por la vida útil del mismo y los menores costos operativos asociados a su uso. Es por ello que en el caso de los chancadores semi-móviles y especialmente en los semi-fijos es de suma importancia su ubicación óptima dentro del yacimiento y no solo a partir de una evaluación de costos, sino también en base a una evaluación de VAN. Según sea el caso hay la posibilidad de un reemplazo total de la flota de camiones por las correas transportadoras y los chancadores móviles. Todo esto conduce a una reducción significativa del costo mina según la configuración del IPCC, también queda susceptible a la coyuntura actual de precios del petróleo, la fuente y suministro energético del país. Finalizamos recomendando el uso de los gráficos como referencia para evaluaciones relacionadas al uso de esta metodología, además de realizar estudios más profundos.

As ore grades decline, waste rock to ore ratios increase and mines become progressively deeper mining operations face challenges in more complex scenarios. Today´s predominant means of material transport in hard-rock surface mines are conventional mining trucks however despite rationalisation efforts material transportation cost increased significantly over the last decades and currently reach up to 60% of overall mining. Thus, considerations and efforts to reduce overall mining costs, promise highest success when focusing on the development of more economic material transport methods. Semi-mobile in-pit crusher and conveyor (SMIPCC) systems represent a viable, safer and less fossil fuel dependent alternative however its viability is still highly argued as inadequate methods for the long term projection of system capacity leads to high uncertainty and consequently higher risk. Therefore, the objective of this thesis is to develop a structured method for the determination of In-pit crusher and conveyor SMIPCC system that incorporates the random behaviour of system elements and their interaction. The method is based on a structured time usage model specific to SMIPCC system supported by a stochastic simulation. The developed method is used in a case study based on a hypothetical mine environment to analyse the system behaviour with regards to time usage model component, system capacity, and cost as a function of truck quantity and stockpile capacity. Furthermore, a comparison between a conventional truck & shovel system and SMIPCC system is provided. Results show that the capacity of a SMIPCC system reaches an optimum in terms of cost per tonne, which is 24% (22 cents per tonne) lower than a truck and shovel system. In addition, the developed method is found to be effective in providing a significantly higher level of information, which can be used in the mining industry to accurately project the economic viability of implementing a SMIPCC system.

An advanced coursework and a project submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements of MSc. Engineering (Mining), November 2015
General For mining operations, both underground and open cast, there are generally accepted criteria used to arrive at the optimum mining method with which to exploit the ore body economically. Having selected the optimum mining method, mining companies should then make the decision to also select the optimum technology to apply given the various options that are now available. In the case of a shallow massive ore body where open-pit mining has been selected as the optimum mining method, the use of conventional trucks and shovels has been the popular choice but over the years, as pit become deeper, and stripping ratios increase, growing interest and adoption of in-pit crushing and conveying for both ore and waste has been gaining ground with several mining sites currently now operating, testing the systems or conducting studies at various stages for In-pit Crushing and Conveying (IPCC) in its different configurations (Chadwick, 2010). Open pit mining general involves the movement of pre-blasted or loose waste ahead of underlying ore out of the pit or to a previously mined part of the pit. This is then followed by the drilling and blasting or loosening of the ore and transportation to the processing plant or stockpiles. The conventional Truck and Shovel open pit operation involves the use of shovels – electric rope shovels, diesel or electric hydraulic shovels or excavators or front-end loaders to load the blasted, or loose waste and ore material in the pit onto mining trucks which haul the material to crushers or stockpiles if it is ore or to waste dumps in the case of waste. In a Fully Mobile IPCC (FMIPCC) system, the broken or loose material in the pit is loaded into a crusher or sizer by a shovel, continuous miner or dozer, crushed to a manageable size and transported by conveyor belts to the waste dump where it is deposited in place using spreaders if it is waste or onto stockpiles if it is ore. A combination of the two systems is where trucks dump material loaded at the face into a semi mobile crusher or sizer located in the pit close to the loading points N BANDA 392438 before conveying to destination thereby reducing truck haulage distance. In the semi-mobile configuration, the crusher is relocated closer to the loading points to minimise the hauling distance. Other various configurations are also employed depending on the various considerations. Although the Truck and Shovel system is considered as the convention in open pit mining, the IPCC system is not a new concept and has been operational on a number of mines worldwide for quite a number of years (Szalanski, 2010). Loading and hauling receive great attention especially in a high volume open pit mines due to the high cost contribution to the overall operation and therefore, if optimised, good cost savings can be realised (Lamb, 2010). Figure 1: Sishen Mining Cost Breakdown In the case of Sishen Loading and Hauling costs constituted 67% of the mining costs including labour mining support services in 2013 (Kumba Iron Ore, 2013). This picture remains unchanged to a large extent. In some cases the hauling cost alone can make up as much as 60% of the mining operating cost (Meredith May, 2012) Selection of a materials handling system between Truck and Shovel (T/S) and In-pit Crushing and Conveying (IPCC) has proven to be difficult due to limited understanding of the IPCC system especially its advantages and disadvantages relative to the Truck and Shovel system. The aim of this research was to unpack these two systems in terms of their applicability using studies conducted at Sishen 6,5% 8,8% 29,1% 22,7% 9,7% 0,6% 1,3% 0,4% 7,0% 4,2% 3,7% 5,9% Sishen Mining Cost 2013 Blasting Drilling Hauling L&H Contractors Loading Maintenance Other Mining Manangement Mining Engineering Mining Other Resource Management SHEQ Mining Support N BANDA 392438 Mine as well as develop some scorecard that could be used to select one over the other one. Sishen Case Study Sishen Mine is an iron ore open pit mine located in the Northern Cape province of South Africa and is part of Kumba Iron Ore Company which is Anglo American PLC. The mine has been in operation since 1953 with the current life of mine going up to 2030. It produces 44Mt tonnes of product from a 56Mt mine ore at a life of mine strip ratio of 4. One of the planned expansion the north part of the mine known as the GR80 and GR50 areas. Mining in these areas will require pre-stripping of 290Mt of clay material over the life of mine to expose the ore in pre volume phases. Figure2: Sishen Pit –Sishen Mine 2014. Sishen mine is constantly evaluating various technologies in its mining operations aimed at improving its bottom line by way of increasing productivity and efficiency, reducing costs and improving safety, however, the last time that the mine considered evaluating a technology that significantly could have resulted in a totally different operational philosophy was i contracted to institute a study to evaluate technology options for mining and moving majority owned by a minimum of 437Mt of calcrete and the underlying pre- g in 2007 when Snowden Mining Consultants run-ofmine areas is in -planned time and were N BANDA 392438 55 Mt of the calcrete/clay material per year from the waste pushback area in the GR80/GR50 area of the mine from 2009 till 2030. Snowden completed the Prefeasibility study in early 2008 in which they evaluated a conventional Truck and Shovel operation as well as IPCC. Economic viability of both systems in various configurations was demonstrated with the use of larger trucks and shovels ranked as the most economic option in terms of Net Present Cost (NPC), unit owning and operating cost per mined tonne and, to a less extent, in terms of risk and other considerations. In this case, the Truck and Shovel option was more economic than both IPCC configurations. However the small difference in the cost figures gave rise to interest in further evaluations. Following the Snowden study, Sishen engaged Sandvik Mining and Construction in 2008, to review the work done by Snowden and provide more detail and practical input to the IPCC system at scoping level. In the review, the IPCC system was shown to be the economic approach for the waste removal from the target area in terms of owning and operating cost. Practicality was also demonstrated and the case for the consideration of the IPCC system was put forward to Sishen. A further consultant, Sinclair Knight Merz (SKM) of Australia, was engaged, in the later part of 2008, to further evaluate and optimise the IPCC option to further demonstrate practically in detail at a feasible study level and strengthen its case by mitigating perceived risk. This included equipment specifications, mine and equipment layout per period per bench and risk assessment on the IPCC options. The mine, however, implemented the conventional truck and shovel option using larger equipment. The final decision was to stick with the current set up of Truck and Shovel system and gradually replace the current fleet of 730E Komatsu (190 tonne payload) trucks with the 930E or equivalent ( 320 tonne payload) and the current XPB 2300 P& H electric rope shovels and CAT 994/Komatsu WA1200 front end loaders with XPC 4100 P&H electric rope shovels, Komatsu PC8000/Liebherr 996 diesel hydraulic shovels and LeTournea L-2350 front end loaders to reduce the number of equipment and manage the operational cost. This decision was based on issues around initial capital investment, flexibility of the system to suit changing mining plans, ability of current personnel to run the system and general low risk appetite for change. The adopted option has its own challenges N BANDA 392438 such as supporting infrastructure requirements, labour intensity and associated low productivity and high cost, fleet management challenges to achieve required productivity constantly, supplies such as fuel and tyres and safety issues due to traffic density. A high level recalculation of the costs using current information was done as part of this research. For simplicity, no escalations or discounting were applied on future expenditure. The estimated unit owning and operating costs in 2014 terms for the study area were as follows:- Fully Mobile IPCC (FMIPCC) option ZAR 10.38/t, Semi Mobile IPCC (SMIPCC) option ZAR 13.12/t, Truck and Shovel option ZAR 15.80/t. The objective of this research is to use lessons from the Sishen case as well as other operations and gather expert views with the aim of establishing criteria that could be applied in a preliminary evaluation that would determine the suitability of either of the materials handling options. General Approach The costs were recalculated using as much current information as possible. Other considerations including advantages and disadvantages of either of the systems were examined in more detail, with real life examples examined where possible. This resulted in the establishment of generalized criteria for the selection of mining and transport technology for a large open pit mine with focus on conventional Truck and Shovel systems on one hand and IPCC systems, in their various formats, on the other. These criteria which identify conditions necessary for the successful adoption and implementation of either of the systems could then be used as input into the decision to carry out any further detailed studies of the options. The previous study reports on the Sishen mine case were examined, input parameters to the calculations checked and the general approached analyzed for practicality. The relative costs were also viewed for comparative purposes. Literature on these two main systems was reviewed including that from conferences. Other large operations running either one or both systems were looked at to gain N BANDA 392438 further insight. Original Equipment suppliers’ views on these systems were also looked at through many articles in the public domain. Sishen mine has previously had the IPCC system running in the same part of the mine in a semi mobile configuration, crushing and conveying waste. It was then changed to become a supplementary system for the ore handling system and the in pit crusher has never been relocated. The Truck and Shovel system took over the movement of all the waste and most of the ore at the mine. Lessons from these experiences were incorporated in this study.

The production of raw materials through mining projects is nowadays very challenging, mainly due to the rapid progress in the industrial and technological fields. On the one hand, they have to fulfill industries' requirements in their demand for materials while making a profit based on the current technologies. On the other hand, they should consider all other limitations, primarily environmental and social challenges that are confronting. The transportation system in any mining project is one of the most significant parts, especially in the technical and economic issues. It must transfer the planned volume of ore/waste that the whole stream of the mining process would not be interrupted and, it can cover the technical challenges and the costs imposed on the project. Additionally, it should be designed and selected to have the lowest environmental impact and the highest safety during the operation. Accordingly, a transportation system selection process that considers all these factors is one of the challenging issues in any mining project. Although the Truck-Shovel system is known as the conventional transportation in open-pit mines, which is preferable because of the low capital cost and high flexibility, it still imposes a high rate of operating costs, safety issues as well as environmental footprints. In-Pit Crushing and Conveying (IPCC) systems are the alternative transportation systems for the Truck-Shovel systems, in which the material is crushed inside the mine’s pit limit and transferred into the outside through conveyor belts. Although these systems are not new, they are mostly neglected as a transportation option basically due to the high capital cost and low flexibility. On the contrary, they can offer more environmentally friendly and safer working areas and a lower operating cost. According to these facts, each transportation system is preferable in a couple of technical, economic, environmental, safety, and social issues. Accordingly, in each circumstance, one or more of these systems can be used in the mining project. However, there is not yet a way or tool that investigates the transportation system selection along with the mine life that takes into account all of these factors. To fill this gap, this project aims to define a model to introduce all these elements while it is interactively connected throughout the mine life. For this and as the first step, the system dynamics modeling is defined and used to build the model for all the technical, economic, environmental, safety, and social factors. As an output of this step, software entitled “TEcESaS Indexes” is designed and produced through Venapp that makes working with the model comfortable. As the second step, a selection method based on the Analytical Hierarchy Process (AHP) is performed that the transportation system selection regarding all the mentioned factors can be made. As the output in this step, the “Sustainability Index” software programmed in the Java language is developed. Considering a hypothetical copper open-pit mine as the case study and implementing the designed software, the results show although the Truck-Shovel system should be used in the first two years of the project (2016 and 2017) in the single expert and deterministic mode, the Fully Mobile In-Pit Crushing and Conveying (FMIPCC) system shows the highest sustainability index among other transportation systems from 2018 until the end of the mine life. While in the group decision making and deterministic simulation, the Truck-Shovel system should be utilized from 2016 to 2020. Additionally, in the group decision making and stochastic mode, the FMIPCC is the selected transportation system with the highest sustainability index probability.

The Sunghir human remains originally consisted of the three associated skeletons from the two burials, Sunghir 1, 2, and 3, plus the remains of six other individuals. Sunghir 1 to 3 consist of largely complete skeletons that sustained the inevitable partial crushing, fragmentation, and bone disintegration that accompanies human remains buried in open air sites for 28,000 years. Sunghir 4 is the adult femur shaft that was ritually placed in the Sunghir 2 and 3 burial, next to the left shoulder of Sunghir 2 (chapter 3). Sunghir 5 is a partial adult cranium, found in the sediments above Grave 1. Sunghir 6 is a mature hemimandible, identified as human after excavation from among the faunal remains above Grave 2. There were also the unnumbered remains of the skeleton in Grave 2bis, which were not retained (see discussion in chapter 3). In addition to these human fossils, the remains of three additional individuals were originally found, numbered Sunghir 7 to 9. Sunghir 7 was found in the deposits between the two graves and consisted of a portion of a human femur, variously described as adolescent or from a young adult female. Sunghir 8 consisted of portions of a femur and a skull (a frontal bone, a probable parietal bone, and a temporal bone), found in 1969 in an additional clay pit. Sunghir 9 was a partial skeleton found in 1972 in an additional clay pit. None of the Sunghir 7 to 9 human remains can be currently located. The Sunghir 7 and 8 remains were briefly described by anthropologists and forensic scientists in Moscow, and the limited information on Sunghir 9 is based on reports by the Vladimir Ceramic Works workers. The available human remains from Sunghir therefore consist of the Sunghir 1 to 3 partial skeletons, the Sunghir 4 partial femur, and the Sunghir 5 and 6 cranium and mandible. These specimens are currently curated in the Laboratory of Anthropological Reconstruction of the Institute of Anthropology and Ethnology of the Russian Academy of Sciences.