scholarly journals ANALISIS PENENTUAN KADAR BATAS OPTIMAL (OPTIMUM CUT-OFF GRADE) DENGAN METODE LANE: STUDI KASUS PENAMBANGAN EMAS BAWAH TANAH

2020 ◽  
Vol 1 (1) ◽  
pp. 1-8
Author(s):  
Sari Uly Uly Sibarani ◽  
Fadhila A Rosyid ◽  
Aryo P Wibowo ◽  
Lilik E Widodo ◽  
M Nur Heriawan
Keyword(s):  
Net Present Value ◽  
Underground Mining ◽  
Commodity Prices ◽  
Open Pit ◽  
Present Value ◽  
Open Pit Mines ◽  
Vein Type ◽  
Result Show ◽  
Cut And Fill ◽  
Mineral Reserves

ABSTRAKKonservasi mineral akan tercapai manakala semakin banyak cadangan mineral tertambang dan meninggalkan sesedikit mungkin material waste. Untuk mencapai hal tersebut salah satu cara yang dapat ditempuh adalah menentukan jumlah cadangan berdasarkan kadar batas yang optimal (optimum cut-off grade). Dalam penentuan optimum cut-off grade, model matematis yang dapat dipergunakan adalah model/persamaan Lane. Metode Lane akan memaksimalkan nilai Net Present Value (NPV) dengan mempertimbangkan 3 variabel, yaitu; variabel ekonomi (harga komoditas dan biaya), distribusi kadar pada endapan, dan kapasitas maksimum pada tahapan penambangan (mining, milling, and refinery). Model Lane biasa diterapkan dalam tambang terbuka, namun dalam penambangan bawah tanah sulit untuk diterapkan. Dalam peper ini akan dikaji penerapan Model Lane dalam penentuan optimum cut-off grade pada penambangan urat (vein) emas bawah tanah dengan metode cut-and-fill. Hasil simulasi menunjukkan nilai optimum cut-off grade yang dinamis dalam memaksimalkan NPV dan nilainya lebih besar dari break even cut-off grade.Kata Kunci: model Lane, optimum cut-off grade, tambang bawah tanah ABSTRACTMineral conservation will be obtained if more mineral reserves are extracted and leaves less waste as possible. One of the methods to achieve those condition is determining the total minable reserves based on the optimum cut-off grade. Optimum cut-off grade can be estimated using Lane Model. Lane Model will maximize the Net Present Value (NPV) by considering 3 variables, i.e; economic variables (commodity prices and costs), grade distribution of deposit, and maximum capacity of each stage of production (mining, milling, and refinery). Lane models are usually applied in open-pit mines, unfortunately it is difficult to apply for underground mining unless some there are some modifications. This paper will examine the application of the Lane Model in determining the optimum cut-off grade in underground gold mine using cut-and-fill method to extract vein type deposit. Simulation result show dynamic optimum cut-off grade which maximizing NPV and generally greater than the break-even cut-off grade.Key Words: Lane model, optimum cut-off grade, underground mine 

The Role of Economic Uncertainty on the Block Economic Value – a New Valuation Approach / Rola Czynnika Niepewności Przy Obliczaniu Wskaźnika Rentowności – Nowe Podejście

2012 ◽  
Vol 57 (4) ◽  
pp. 991-1014 ◽  
Author(s):  
H. Dehghani ◽  
M. Ataee-Pour
Keyword(s):  
Net Present Value ◽  
Economic Value ◽  
Operating Cost ◽  
Mine Planning ◽  
Open Pit ◽  
Economic Uncertainty ◽  
Present Value ◽  
Wrong Decision ◽  
Binomial Tree ◽  
Conventional Methods

Abstract The block economic value (BEV) is one of the most important parameters in mine evaluation. This parameter can affect significant factors such as mining sequence, final pit limit and net present value. Nowadays, the aim of open pit mine planning is to define optimum pit limits and an optimum life of mine production scheduling that maximizes the pit value under some technical and operational constraints. Therefore, it is necessary to calculate the block economic value at the first stage of the mine planning process, correctly. Unrealistic block economic value estimation may cause the mining project managers to make the wrong decision and thus may impose inexpiable losses to the project. The effective parameters such as metal price, operating cost, grade and so forth are always assumed certain in the conventional methods of BEV calculation. While, obviously, these parameters have uncertain nature. Therefore, usually, the conventional methods results are far from reality. In order to solve this problem, a new technique is used base on an invented binomial tree which is developed in this research. This method can calculate the BEV and project NPV under economic uncertainty. In this paper, the BEV and project NPV were initially determined using Whittle formula based on certain economic parameters and a multivariate binomial tree based on the economic uncertainties such as the metal price and cost uncertainties. Finally the results were compared. It is concluded that applying the metal price and cost uncertainties causes the calculated block economic value and net present value to be more realistic than certain conditions.

scholarly journals Project optimization

2015 ◽  
Vol 68 (1) ◽  
pp. 97-102 ◽  
Author(s):  
Carla De Carli ◽  
Peroni Rodrigo de Lemos
Keyword(s):  
Net Present Value ◽  
Underground Mining ◽  
Mineral Resources ◽  
Mineral Deposit ◽  
Economic Feasibility ◽  
Open Pit ◽  
Optimum Depth ◽  
Combination Of Methods ◽  
Definition Of ◽  
Project Optimization

A mineral deposit can be exploited by underground methods or by open pit methods, defined according to their characteristics, especially in relation to depth and geometry of the ore body and the economic feasibility of the methods. However, there are cases in which the alternative that represents the best return for the project is the application of combined methods, i.e., the open pit followed by underground mining. In these situations, the major difficulty is the definition of the transition point of methods, seeking to maximize the net present value of the project and the use of mineral resources. The premature suspension of activities in the open pit, as well as advancing beyond the optimum depth, can derail the implementation of the combination of methods, so it is important to analyze the project not only individually but also in an integrated way.

scholarly journals Sequencing of ore columns for planning of large underground mines

Mining Scince ◽  
2019 ◽  
Vol 26 ◽  
Author(s):  
Hylke Glass ◽  
Gert Van Hout
Keyword(s):  
Net Present Value ◽  
Underground Mining ◽  
Underground Mines ◽  
Systematic Design ◽  
Present Value ◽  
Block Caving ◽  
Initiation Point ◽  
Mining Technique ◽  
Mine Economics ◽  
Large Deposits

Block caving is an underground mining technique which extracts ore from the base, rather than from the top, of typically massive deposits. Mining infrastructure is developed below the deposit before extraction commences. A network of tunnels provides access to a collection of drawpoints from which ore is hauled. With large deposits, not all drawpoints are developed simultaneously and the opening of drawpoints is sequenced to facilitate orderly extraction of ore columns above drawpoints. Sequencing fixes the initiation point for the entire block cave, or a part of it, as well as identifying the direction of cave advancement. The drawpoint opening sequence exerts influence on the block cave mine economics. This paper discusses the optimisation of sequencing based on the net present value associated with extraction over the life-of-mine. It is shown that the maximum attainable net present value is obtained by a sequence in which ore columns are ranked in descending order of value. If significant variation of grade is present inside columns, an iterative procedure is given which corrects the sequence which yields the maximum net present value. The sequence with maximum net present value may not be practical or attractive from a caving perspective. Systematic design of sequences which permit orderly development of a block cave is discussed. To provide context, the net present value obtained from these feasible sequences is compared with the maximum attainable net present value. It is shown that the best feasible sequences are preferentially initiated in zones with columns of high-grade ore.

scholarly journals A sequentially advancing algorithm based on multi-value dynamic programming for the cut-off grade optimization in open-pit metalliferous deposits

2021 ◽  
Author(s):  
Pritam Biswas ◽  
Rabindra Kumar Sinha ◽  
Phalguni Sen
Keyword(s):  
Dynamic Programming ◽  
Net Present Value ◽  
Real Life ◽  
Surface Mining ◽  
Life Time ◽  
Copper Deposit ◽  
Early Years ◽  
Open Pit ◽  
Present Value ◽  
Copper Mine

Abstract In techno-economic concern, cut-off grade (COG) optimization is the key for efficient mineral liquidation from the huge metalliferous surface mining sector. In this paper, a sequentially advancing algorithm based on exact multi-value dynamic programming (MDP) has been developed to determine the optimum COG of an open-pit metalliferous deposit. The proposed COG optimization algorithm aims to overcome the limitations of straightforward classical techniques in determining the optimum COG. This discrete COG-MDP model is the first of its kind and has the novelty of dealing with the simulation of eight dynamic possibilities to achieve the maximal Net Present Value (NPV). A high-level programming language (Python) has been used to develop the computer model to deal with the complexity of handling a minimum of 500 series of dynamic variables with a precision value of 0.01% in grade bins. This model can generate results in polynomial-time from the complex mine, mill, and smelter and refinery system corresponding to various limiting conditions. The prime objective considered in the model is to optimize the COG of a metalliferous deposit. The model validation has been done using a real-life case study of an open-pit copper mine in India (Malanjkhand Copper Mine, HCL), considering the fixed yearly output of the mining, milling, and smelting and refining. In this study, the optimum COG for the Malanjkhand copper deposit has been found to be (0.33%, 0.23%, 0.52%, 0.26%, 0.27%, 0.22%, 0.24%) with a maximum NPV of ₹ (12204, 14653, 16948, 14609, 21454, 26717, 38821) million corresponding to various scenarios. The findings also show that the present value of net cash-flow grows in the early years, peaks at a specified mid-life time, and then drops as the reserve is depleted. The present value gradually hits zero after the project’s life cycle, confirming the typical pattern of other mining firms.

scholarly journals Conversion of the planted forest with pinus to grain production in the Brazilian conditions: a study showing the economic perspectives

2021 ◽  
Vol 8 (2) ◽  
pp. 1489-1496
Author(s):  
Randy Speltz ◽  
Risely Ferraz Almeida
Keyword(s):  
Environmental Sustainability ◽  
Net Present Value ◽  
Positive Impact ◽  
Commodity Prices ◽  
Global Scale ◽  
Grain Production ◽  
Planted Forest ◽  
Present Value ◽  
Soybean Production ◽  
Positive Economic

The Brazilian roundwood production of planted forest (PF) is large and turns Brazil, a prominent player on a global scale. A study was established on a farm located in Tibagi, Paraná, Brazil. We simulated two scenarios: A (continuity planting of pinus), and B (conversion of pinus to corn/soybean production). Results showed that both the productions of pinus and the rotation of soybean/corn are viable economic alternatives. If make-decided, the conversion of pinus to corn/soybean production also presented optimal with an increase of net present value, annual net present value, and internal rate of return, respectively from 9.8 %; R$ 1,519.48; and R$ 160.57 (PF), to 13.7 %; R$ 3,389.50; R$ 304.93 (soybean/corn). The rotation of soybean/corn presented a positive economic flux after the 4th crop-year due to the high initial cost of stump-removal. While, the pinus showed a positive economic flux after the 7th crop-year with the thinning/harvest in the 7th, 10th, 14th, 16th, and 20th years. Based on our results and from literature, we conclude that there is an increase of grain areas due to the influence of global grain consumption and high commodity prices, which can cause a conversion of PF to grain production areas due to higher better economic gains. However, farmers should maintain the economic-health of the property with the diversity of viable economic crops (i.e., pinus and corn/soybean), and the positive impact of planted forest on environmental sustainability.

scholarly journals Going Underground for Ferronickel Mining in Greece: Preliminary Feasibility and Potential Benefits

2021 ◽  
Vol 5 (1) ◽  
pp. 6
Author(s):  
Andreas Benardos ◽  
Ioannis Vlachogiannis ◽  
Christos Stenos ◽  
Spyros Pappas ◽  
Georgios Bourmas ◽  
...  
Keyword(s):  
Underground Mining ◽  
Open Pit ◽  
Environmental Footprint ◽  
Open Pit Mines ◽  
Model Project ◽  
Potential Benefits

The gradual elimination of rich and surficial-located Ni reserves mandates the assessment regarding the gradual switch from open-pit mines to underground mining schemes. This could allow for the continuation of the steady ore supply and furthermore could assist in minimizing the environmental footprint of the exploitations. This paper investigates the possibility of adopting an underground exploitation scheme and provides data on the preliminary feasibility of the endeavor for the Vrysakia deposit that was selected as a model project. It was found that such solutions proved to be technically sound, also yielding considerable results from a financial viewpoint.

A Dynamic-Programming Based Model for Phase-Mining Optimization in Open-Pit Metal Mines

2013 ◽  
Vol 316-317 ◽  
pp. 896-901
Author(s):  
Qing Wang ◽  
Xiao Chuan Xu ◽  
Xiao Wei Gu
Keyword(s):  
Dynamic Programming ◽  
Net Present Value ◽  
Open Pit ◽  
Present Value ◽  
Dynamic Nature ◽  
Time And Space ◽  
Full Account ◽  
Metal Mines

Three important aspects of phase-mining must be optimized: the number of phases, the geometry and position of each phase-pit (including the ultimate pit), and the ore and waste quantities to be mined in each phase. A model is presented in this paper in which, a sequence of geologically optimum pits are first generated and then dynamically evaluated to simultaneously optimize the above three aspects, with the objective of maximizing the overall net present value. The model takes into full account of the dynamic nature of the problem with respect to both time and space, and is robust in accommodating different pit wall slopes and different bench heights.

Substantiation of underground geotechnology at the combined mining of ore deposits on the basis of accounting the features of transients

2020 ◽  
pp. 326-337
Author(s):  
I. V. Sokolov ◽  
Y. G. Antipin ◽  
A. A. Smirnov ◽  
I. V. Nikitin
Keyword(s):  
Transition Zone ◽  
Net Present Value ◽  
Transition Period ◽  
Underground Mining ◽  
Methodological Approach ◽  
Stable State ◽  
Ore Deposits ◽  
Open Pit ◽  
Chamber System ◽  
Specific Factors

Within the new methodological approach, a scientific and technical substantiation of the optimal underground geotechnology with the combined development of ore deposits based on the characteristics of transients was completed. Based on the analysis of experience of the combined development of ore deposits, the transition process features were revealed: a sharp decrease in the production capacity of the enterprise and an increase in capital investments, and its main goal was determined - to create the most favorable conditions for the transformation of the mining enterprise from one stable state to another. The types of transition areas are systematized depending on the scheme of conducting open and underground mining during the transition period. Four rational options for underground geotechnology that take into account specific factors and conditions formed during open mining, providing optimal parameters for the development of underground mining at a new stable stage, are developed. The method of economic and mathematical modeling for the conditions of the of the Safyanovsky copper deposits investigated the influence of specific factors on the gross profit - the depth of the open pit, which varies in the range from 140 to 380 m, and the depth of the reserves under open pit, which varies in the range from 80 to 320 m. The best option for underground geotechnology, which provides for the phased opening of underquarry reserves by a autoincline from the open pit and an runaway from the surface, mining the transition zone by level-chamber system with filling under ore insulating pillar formed within the transition zone, and the further development of the main reserves by level-chamber system with filling under filling mass, is established by the criterion of net present value.

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