Optimization of production planning in underground mining

Use of Integer programming (IP) or mixed integer programming (MIP) for formulation of mine optimization problem is best suited modelling approach for underground mining. Optimization algorithm for underground stope design problems cannot be generalised as geotechnical constraints for each method is different. This project concentrates on optimization model for open stoping mining method. The stope design model maximizes Net cash flow of the stope while adhering to the stope constraints. The methodology considers open stoping sequence, in which every block is moved towards the cross-cuts at the lower level. In this thesis, stopes are designed to maximize the undiscounted cash flow from the stope after satisfying stope height and extraction angle constraints. An integer programming formulation is developed and solved using CPLEX solver for single stope. The proposed algorithm is solved for first stope and then blocks for the crown pillar for first stope is identified. After eliminating the first stope and respective crown pillar data from the data set, algorithm is solved again for the second stope from the remaining data set. After stope design, production scheduling is done by applying heuristic approaches. Blocks from the stopes are extracted heuristically satisfying extracting angle, mining and processing constraints. Initially blocks from the first stope are selected and then to fulfil the constraints, some of the blocks from the second stope are selected. A study is carried out on the part of the Zinc mine data of India which contains 4992 number of blocks. Total 3 numbers of stopes are designed. The NPV of the considered data is found to be 7313.346 million rupees in 3 periods with total tonnage of 1.103 million tonnes. Metal content in 3 periods is found to be 86.485 thousand Tonnes. The overall dilution is found to be 3.82% with average dilution of 2.692

Presidential address: Optimization in underground mine planning-developments and opportunities.

Presidential address presented at the The Southern African Institute of Mining and Metallurgy Annual General Meeting on 11 August 2016.The application of mining-specific and generic optimization techniques in the mining industry is deeply rooted in the discipline of operations research (OR). OR has its origins in the British Royal Air Force and Army around the early 1930s. Its development continued during and after World War II. The application of OR techniques to optimization in the mining industry started to emerge in the early 1960s. Since then, optimization techniques have been applied to solve widely different mine planning problems. Mine planning plays an important role in the mine value chain as operations are measured against planned targets in order to evaluate operational performance. An optimized mine plan is expected to be sufficiently robust to ensure that actual outcomes are close or equal to planned targets, provided that variances due to poor performance are minimal. Despite the proliferation of optimization techniques in mine planning, optimization in underground mine planning is less extensively developed and applied than in open pit mine planning. This is due to the fact that optimization in underground mine planning is far more complex than open pit optimization. Optimization in underground mine planning has been executed in four broad areas, namely: development layouts, stope envelopes, production scheduling, and equipment selection and utilization. This paper highlights commonly applied optimization techniques, explores developments and opportunities, and makes a case for integrated three-dimensional (3D) stochastic optimization, in underground mine planning.MvdH201

IMPROVING THE METHOD OF OPEN-PIT LIGNITE DEPOSITS DEVELOPMENT IN UKRAINE

Subject of the research is open-pit mining concerning a full- field industrial development of a number of lignite deposits; feasibility study has been performed for them as for the efficient environmental friendly processing of coal and associated minerals. Objective of the research is to develop both methodology and conceptual approaches to high-productive, economically viable, and environmental friendly methods for open-pit lignite mining in the context of suprasalt depressive basins. Task of the research is to analyze the current state of lignite mining in Ukraine; to characterize a new genetic Ukrainian coal type from geological and industrial viewpoint; to substantiate parameters of lignite open-pit mining on the basis of Novo-Dmytrivka mining and industrial district; to expand the capacities of lignite mining on the basis of Novo-Dmytrivka, Bantysh, Stepkivka, and Bereka deposits; to substantiate the integrated use of diverse rock masses in the context of the national economy; to use lignite in terms of its power; to produce montan wax; to apply sodium humite in the context of agriculture; to use overburden rocks for the construction of bordering dams of powerful water storages; and to develop recommendations concerning the design of Novo-Dmytrivka mining and industrial system with the integrated development of lignite and associated minerals. Methods of the research are: analytical estimation of resources of lignite deposits; geological and engineering-technical analysis; and integrated and feasibility studies of indices of mining and opening operations. Optimization of the process solutions relies upon the analysis of changes in rock mass coefficient use within the open-pit area in the context of complete land reclamation of the disturbed land and the development of new productive land instead of the littered territories. The updated research method is to determine the basic technological parameters of equipment taking into consideration significant water inflow in terms of working areas as well as the inflows effect on the output of the lignite open pit depending upon changes in the depth of mine workings. The carried out research helped study more thoroughly the geological and engineering-technical features of lignite deposits in Ukraine. Their geological structures, coal-bearing capacity and the coal grades, total reserves, and their commercial significance have been determined. Parameters of benches and working sites have been substantiated. The parameters make it possible to decrease the current volume of overburden rock mining and to transfer their maximum values to the final stage of the open pit operation. Rational systems of mining and transportation equipment for the development of the open-pit field in terms of criteria of capacity, efficiency, and power consumption have been substantiated involving different traffic flows of rock mass movement in open pits and at the surface. There were issued recommendations to design the development of Novo-Dmytrivka lignite deposit. Relying upon the analyzed deposits of north-west Donbas, it is expedient to develop the unified coal-mining complex for the processing of lignite and associated minerals to be used by plants of building materials and structures as well as chemical and metallurgical plants as the basic raw material. There has been substantiated a possibility of commercial development of a number of lignite deposits in Ukraine to develop mining and preproduction complex with coal output at the level of 9-10 min t/y and 23-24 min t/y of coaly mass as well as their processing by thermal power station which capacity is 1800-2400 MW; a plant to produce 15 thousand tons of montan wax a year; briquetting factory which capacity is 2 min t/y; and a concrete product plant to manufacture building structures with a capacity of 1 min of m2/y

Evaluation of methods for stope design in mining and potential of improvement by pre-investigations

The importance of stope design for mine planning is considerable. Therefore, stope design and its challenges have been in the focus of research for the past 50 years. Empirical, numerical and analytical methods for stope design have been developed over the past decades in order to improve this process. This thesis is assessing which areas for improvement there still are and which problems are still only unsatisfactorily solved. After establishing background knowledge about the importance of stope design for mine planning and evaluating the factors influencing stope design, the focus is laid on the development of stope design methods in the past, as well as current research related to the topic, to create a comprehensive overview of recent and future developments. This is done by means of a literature review and research analysis. On the other side, the mining industry´s needs and challenges related to stope design are assessed, by means of survey, mine visit and interview. The insights gained in both parts are compared and checked for potential harmonies and disharmonies. Finally, from those conclusions practical recommendations for the GAGS-project are extracted and consecutively presented. In stope design research the focus and dominance of empirical methods has slowly shifted towards more research being conducted in the area of numerical and analytical methods. It can also be concluded that numerical methods and personal expertise are far more important for stope design within industry than commonly assumed. It was identified that in order to improve stope design, it is desired to increase the amount of geotechnical data acquired, the software improved, and stope design integrated within the general mine planning process. Additionally, interesting insights were gained by an in-depth analysis of survey responses, for example, the outstanding importance of the cut-off grade for stope design within gold mining operations. In order to allow for an optimal acceptance of novel geotechnical methods for stope design, the acquired data should be implementable into stope design within three days, preferably be compatible or implemented within a software and allow for stope design to be integrated into general mine planning. To promote the benefits a comprehensive scientific case-study demonstrating the realized benefits should be performed

Solution procedures for block selection and sequencing in flat-bedded potash underground mines

Phosphates, and especially potash, play an essential role in the increase in crop yields. Potash is mined in Germany in underground mines using a conventional drill-and-blast technique. The most commercially valuable mineral contained in potash is the potassium chloride that is separated from the potash in aboveground processing plants. The processing plants perform economically best if the amount of potassium contained in the output is equal to a specific value, the so-called optimal operating point. Therefore, quality-oriented extraction plays a decisive role in reducing processing costs. In this paper, we mathematically formulate a block selection and sequencing problem with a quality-oriented objective function that aims at an even extraction of potash regarding the potassium content. We, thereby, have to observe some precedence relations, maximum and minimum limits of the output, and a quality tolerance range within a given planning horizon. We model the problem as a mixed-integer nonlinear program which is then linearized. We show that our problem is NP-hard in the strong sense with the result that a MILP-solver cannot find feasible solutions for the most challenging problem instances at hand. Accordingly, we develop a problem-specific constructive heuristic that finds feasible solutions for each of our test instances. A comprehensive experimental performance analysis shows that a sophisticated combination of the proposed heuristic with the mathematical program improves the feasible solutions achieved by the heuristic, on average, by 92.5%