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By Hong-ying Xia, Bao-bao Wang, Jin-hui Peng, Bing-guo Liu, Li-bo Zhang, Zhi-qiang Li

Based on optimization using response surface methodology designed by Box- Behnken, to study the interaction of wet industrial salt with moisture drying temperature (50-90 ); duration (10-50s); and the weight of the materials (20-60g). The results show that: the experimental parameter conforms to the quadratic equation model to influence the moisture content and the dehydration speed., in analyzing the significance and the interaction of various factors, the optimum by the Design Expert software conditions for drying with microwave radiation include temperature of 90 , duration of 10s, and sample mass of 26g. Verified by experiment, the moisture content after drying is less than 0.25% and the dehydration rate reached 1.37g/min, between the predicted value and the actual value confirmed good fitting degree.

Jan 1, 2015

By Z. Y. Ma, H. Y. Yang

The process of microwave-ultrasound assisted leaching of valuable metals from copper anode slime was proposed in this paper. Design of experiments has been used to study the effect of the main leaching parameters, such as microwave power, ultrasound power and reaction time. The central composite design (CCD) was used to predict the maximum leaching efficiency of copper, tellurium and selenium. The experimental data obtained were fitted to a second-order polynomial equation, and they also were analyzed by analysis of variance (ANOVA). The 3-D response surface plots and the contour plots were applied to determine the optimal conditions. The optimum conditions of microwave-ultrasound assisted leaching process were: microwave power 834W, ultrasonic power 638W and reaction time 403s. Under these conditions, the experimental leaching efficiency of copper, tellurium and selenium were 98.88±0.56% 98.96±0.78% and 98.57±0.67%, respectively, which agreed well with the predicted values.

Jan 1, 2014

By B. Clermont

Ball mills are usually the largest consumers of energy within a mineral concentrator. Comminution is responsible for 50% of the total mineral processing cost. In today?s global markets, expanding mining groups are trying to optimize mill performances. Since comminution is concerned with liberating valuable minerals for recovery in the separation process, it is crucial to run the mills at the best operating conditions which lead to good liberation at competitive throughputs with minimum costs (energy and wear). The high availability of the equipment is also essential to maximize production and profit. To reach this key objective, continuous and reliable information about the mill operation is vital. An innovative tool which can deliver information about in-mill dynamics has been developed by Magotteaux. It can provide online and accurate measurements of the degree of grinding ball fill and pulp position for timely decision making and actions. This tool could be used on its own or linked to an automatic grinding ball loading system named Magoload. Therefore, ball load could be kept constant by using direct measurement. This article describes the Sensomag and presents some of the major improvements that can be achieved with it. Some other promising avenues are still to be explored. Keywords: Comminution, process control, process optimization, process instrumentation, online analysis.

Jan 1, 2010

By Howard M. Wells

The investment worth of a mineral deposit can only be realistically evaluated in relation to specified engineering design criteria which fully detail the proposed method of exploitation. The operational design of a mine falls essentially within the technical discipline of the mining engineer, under the constraint that the technical design should be aimed at optimizing the financial attractiveness of the project. In the case of a marginally viable proposition it becomes vitally necessary to identify the best set of design parameters which together will add up to an optimum investment proposal. This paper examines some fundamental logic of optimization for a "wasting asset" type of investment such as a mine, with special reference to the rate of annual production and the strategy of selective mining.

Jan 12, 1978

By Howard M. Wells

The investment worth of a mineral deposit can only be realistically evaluated in relation to specified engineering design criteria which fully detail the proposed method of exploitation. The operational design of a mine falls essentially within the technical discipline of the mining engineer, under the constraint that the technical design should be aimed at optimizing the financial attractiveness of the project. In the case of a marginally viable proposition it becomes vitally necessary to identify the best set of design parameters which together will add up to an optimum investment proposal. This paper examines some fundamental logic of optimization for a "wasting asset" type of investment such as a mine, with special reference to the rate of annual production and the strategy of selective mining.

Jan 1, 1979

By T. J. McKeon

Gravity separators such as spirals are commonly used in multistage cleaning and scavenging circuits to improve the quality and recovery of concentrates produced in the industrial minerals industry. Unfortunately, field surveys suggest that many industrial operations are poorly configured in terms of equipment layout. This shortcoming can often be attributed to a failure by engineers to make use of fundamental process engineering tools for circuit design. One of the most important of these is linear circuit analysis. This powerful tool makes it possible to mathematically compare the relative efficiency of circuit configurations in advance of experimental testing. This article provides a basic review of the linear circuit analysis concept and discusses some of the key insights it provides for the layout of multistage circuits. An industrial case study is provided to show the tremendous impact that this process engineering tool can have on the design of multistage spiral circuits in a heavy mineral wet plant.

Feb 1, 2012

By Charle Pelley, Kosta Fytas, Peter Calder

"A computer model has been developed which is capable of evaluating alternative production schedules (long- and short range) of an open pit mine once the ultimate pit limits have been defined. The model user can choose the best alternative according to cash flow considerations and the particular mining conditions. The model involves a combination of simulation for long range production scheduling and linear programming for short range scheduling. IntroductionMining of mineral deposits in such a fashion so that, at depletion the maximum possible profit is realized, has been a very old problem of the mineral industry. In the past, when high-grade ore reserves were readily available and profits were very high, no question of optimum profitability was raised.However, recently the complexity of both open pit and underground mining has been increased tremendously. The additional problems of continuously rising production costs on one hand and of depressed metal prices worldwide on the other, have been demanding optimum profitabiliy from every mining venture .Particularly in the area of open pit mining, the sequence of ore and waste extraction has now become very important since the size of the pits and of the mining equipment has increased enormously. The process of open pit mining involves a continuous change of the open pit surface and there are many feasible plans of extraction which lead to the same final pit shape (ultimate pit limits). Each of these feasible plans generates a production schedule over the entire mine life, which mayor may not be optimal."

Jan 1, 1987

By G. T. Lineberry

Horsepower requirement is recognized as a most important equipment characteristic. Other critical equipment characteristics will be isolated and analyzed by traditional operations research techniques, using off-highway trucks as an archetype. A computer search technique has been developed, employing various production and cost analyses. With this model, the optimum combination of horsepower, capacity, and velocity can be found, minimizing handling cost per ton. An example of the program's use and interpretation of its results will conclude the paper.

Jan 1, 1984

By Bingguo Liu, Daifu Huang, Jinhui Peng

"The conditions to prepare U3O8 by calcination from ammonium diuranate were optimized, and the response surface design method was applied to analyze the influence on the total uranium and U+4 of calcination temperature, calcination time and mass of sample. A quadratic equation model for the total uranium and U+4 of U3O8 was built and the effects of main factors and their corresponding relationships were obtained. The analysis of variance shows that calcination temperature and calcination time significantly affected the value of total uranium and U+4 of U3O8. The optimal calcination conditions were as follows: calcination temperature 931.83 K, calcination time 24.32 min and 43.89 g. Under these conditions the value of total uranium and U+4 of U3O8 was 84.78% and 28.02%, respectively. The validity of the model was confirmed experimentally and the results were satisfactory.IntroductionNuclear energy is clean, effective, and a sustainable from of energy. It plays an important role in overcoming the impending global energy crisis, and in reducing energy vulnerability. In addition, nuclear energy is a possible cheaper and cleaner source of energy compared to fossil fuels, with no not really, mining of uranium produces CO2 contribution to green house gases [1]. Uranium dioxide, one of the most important fuel pellets used as nuclear fuel in light water reactors, is manufactured by calcining ammonium diuranate to triuranium octaoxide, followed by its reduction to uranium dioxide using cracked ammonia at 700°C [2]. Earlier attempts to optimize the important calcination process through several common techniques have not yielded desirable results [3]. These techniques either rely on the classical one parameter at a time approach that ignores the combined interactions between physicochemical parameters, or are theoretical in nature. Furthermore, these techniques also require large number of experimental data to be generated [4]. In order to produce triuranium octaoxide in an optimized manner, which considers the interaction of different process parameters [5], there is a need to adopt a multivariate statistical technique."

Jan 1, 2011

By J. Pelders, F. Magweregwede, S. M. Rupprecht

Increased depths of conventional gold and platinum mines, longer travelling times as working places move further from the shaft, and ancillary activities taking place in the mining cycle reduce the useable time spent at them workface. Current shift lengths of 8 hours 20 minutes may no longer be adequate ton complete required mining activities.The impact of mineworker commuting times on shift work is also not well understood. The aim of this research was to draft a framework to optimize shift cycles in order to maximize productivity, health, safety, and wellness in the South African mining sector. The framework was informed by a review of the literature, case studies at a local gold mine and platinum mine, and a workshop with industry experts. The findings indicate potential advantages of extended shift lengths and continuous operations, such as improved productivity, asset utilization, and employee morale. However, concerns included fatigue and the associated safety hazards, particularly when working longer shifts, night shifts, and numerous consecutive shifts. Job demands, personal factors, and commuting times are further considerations when scheduling shifts. The ideal shift system for the mining sector should holistically consider and balance operational requirements, health and safety, and employees’ and their families’ requirements, and suit the unique needs of each operation. Changes in shift cycles will require a structured change management process, which involves all stakeholders, and could help to enhance the viability of the South African mining sector.

Aug 1, 2021

By P. R. Segopolo

"The purpose of the project is to convert current shuttle car utilization on an underground coal mine to best practice by focusing on change-out points and tramming routes, which have a major influence on shuttle car away times. Time studies were an integral part of the project as these enabled the determination of shuttle car away times. An indirect proportional relationship between shuttle car away times and productivity is established. Through the time studies, it is deduced that a third shuttle car will make an insignificant contribution to production when there is only one split open. During this time, maintenance on the third car can be optimized. In order to satisfy the mine’s key performance indicator of keeping shuttle car away times less than 75 seconds, a belt extension must be scheduled after the third split is open. It is established that at any given time, a minimum of two shuttle cars should be used. When cutting on the left-hand-side of the belt road with only two shuttle cars available, the centre and left (left of the feeder breaker) shuttle cars should be used for coal hauling. When cutting on the right-hand-side, the centre and the right-hand-side cars should be used. If only one shuttle car is available, the centre car is the most efficient to use. Alternative anchoring configurations can be employed so as to enable cars (left or right, especially) to reach the opposite extremities of the panel and hence minimize cable length restrictions. Paper written on project work carried out in partial fulfilment of BSc. Eng. (MiningEngineering)"

Jan 1, 2015

By M. Saba

In cyanide leaching procedure, achieving an acceptable efficiency for silver and gold is very time-consuming, thus, enough studies have not been performed for optimization and modeling of this process. The kinetics of cyanide leaching includes two steps: first step comprises a sharp slope while the other has a slight increasing trend. In the present study, in order to reduce the time and cost, the cyanide leaching process of a sulfide silver/gold ore was optimized in the first period. The applied parameters and their ranges are: temperature 20-40 (°C); time 1-8 (hrs); cyanide concentration 1-2 (mole cyanide / mole Cu); the percentage of solid to liquid 1-2 (%) and pH 10-12. For design of experiments fractional factorial 2(5-1) was used. Also four center points were applied to increase the accuracy of the model. In addition, by analysis of variance (ANOVA) the most effective parameters were identified and the optimized condition was determined. A regression model was proposed to describe the effects of independent variables and their interacting role on silver recovery. Results showed that the model was linear for silver and nonlinear for gold. In the gold recovery process, the two important parameters are time and pH with the former being more effective. Due to the existence of cyanide ions in the medium, temperature and cyanide concentration have less influence in the gold recovery process. Solid to liquid ratio, in addition, comprises a slight negative impact on the procedure. This emphasizes the different kinetics of silver/ gold cyanide leaching. Finally, using the optimum condition the amount of silver and gold obtained were 61% and 67% in 8 hours, respectively. While in general conditions, the results were 37% and 54% in 24 hours, respectively. Keywords: cyanide leaching, refractory gold/silver ore, modeling, optimization

Sep 1, 2012

By B. C. Jena

In a chromite smelting process for the production of high-carbon ferrochromium, the slag composition profoundly affects operating conditions and the economic performance of the process. For a Canadian chromite concentrate, optimum slag composition and operating temperature were determined by process simulation with a computer model, which is based on parameters, such as the minimisation of slag volume, liquidus temperature, electrical energy consumption and chromium losses. Chromium recoveries are identified for slag compositions spanning wide concentration ranges within the quaternary system MgO-AI2O3- SiO2-CaO. The simulated data are compared with the experimental results.

Jan 1, 1994

By Y. V. Vasylchuk

This paper presents an algorithm for optimizing the classification of surface mine material subject to excavating constraints. High-resolution expected profit models are input and optimized to classification maps subject to site-specific rectangular excavating constraints. This optimization problem defies traditional closed-form analytical solutions; a practical heuristic algorithm has been developed to quickly determine the optimal final destination for the material subject to realistic constraints. The optimization is fast and generates results that achieve up to 98–99% of the total expected profit achieved with free selection. This algorithm provides a fast viable option for practical application in short-term grade control and in managing multiple realizations in long-term resource estimation.

By Qinghua Tian, Zhipeng Xu, Dong Li, Xueyi Guo, Liu Zhu

A possible process for extracting tellurium and antimony from a residue generated in alkaline sulfide leaching of telluriumbearing alkaline skimming slag was proposed. The central composite design was employed to define the optimal leaching conditions for tellurium and antimony extractions from the residue sample. Using a 23 factorial matrix, the best performance for tellurium and antimony extractions (96.36% and 99.64%) were obtained at 175 g L−1 Na2S concentration for 80 °C during 60 min. The notable degree for influencing tellurium and antimony extractions was leaching temperature, Na2S concentration, and leaching time. The analysis of variance results indicated that the regression model was significant and suitable to be used for the optimization of independent variables within the range. The model was validated under optimal operating conditions based on the experimental design results. Antimony and tellurium in the leach liquor were separated and recovered by H2O2 oxidation followed by Na2S-Na2SO3 reduction. 98.93% of antimony was precipitated selectively during H2O2 oxidation, while 95.06% of tellurium was precipitated during Na2S-Na2SO3 reduction. NaSb(OH)6 and elemental tellurium was obtained as the product.

By Qinghua Tian, Zhipeng Xu, Dong Li, Xueyi Guo, Liu Zhu

A possible process for extracting tellurium and antimony from a residue generated in alkaline sulfide leaching of telluriumbearing alkaline skimming slag was proposed. The central composite design was employed to define the optimal leaching conditions for tellurium and antimony extractions from the residue sample. Using a 23 factorial matrix, the best performance for tellurium and antimony extractions (96.36% and 99.64%) were obtained at 175 g L−1 Na2S concentration for 80 °C during 60 min. The notable degree for influencing tellurium and antimony extractions was leaching temperature, Na2S concentration, and leaching time. The analysis of variance results indicated that the regression model was significant and suitable to be used for the optimization of independent variables within the range. The model was validated under optimal operating conditions based on the experimental design results. Antimony and tellurium in the leach liquor were separated and recovered by H2O2 oxidation followed by Na2S-Na2SO3 reduction. 98.93% of antimony was precipitated selectively during H2O2 oxidation, while 95.06% of tellurium was precipitated during Na2S-Na2SO3 reduction. NaSb(OH)6 and elemental tellurium was obtained as the product.

By Dirk Verhulst

The Altair Hydrochloride Pigment Process is a new ?third route?, besides the established high-temperature chloride process and the older sulfate process, to manufacture TiO2 pigment from ilmenite ore. It has been tested at a scale of 5 t/day feed. The ore concentrate is digested in high-acid, high total chloride solution (+/- 39% Cl). Titanium and iron both go into solution. Iron is separated as FeCl2 crystals after reduction and cooling. Titanium is transferred by solvent extraction into a purified, high-Ti stream. It is spray-hydrolyzed to produce a TiO2 hydrate and further calcined with additives into high-quality pigment. HCl solutions generated by pyrohydrolysis and spray hydrolysis are treated by pressure-swing distillation to regenerate HCl gas for re-injection into the digestion reactor. All chloride streams are recycled. Recent work has concentrated on optimization, particularly in 3 areas: - Solvent extraction: a new organic mixture, including a new diluent, makes it possible to work at room temperature, to avoid TiO2 hydrolysis problems and to improve phase disengagement and impurity separation. - Pigment finishing: a systematic study of the parameters involved, followed by long runs in the best conditions confirm pigment quality. - Flow sheet optimization: innovative modifications of the conditions of spray hydrolysis and pyrohydrolysis, combined with re-routing of streams achieve significant energy savings. A 100 t/year pilot plant including these features as well as other process improvements is under construction.

Jan 1, 2006

By L. Galarza

"INTRODUCTION Beneficiation of ores and minerals in a concentrator plant requires a significant amount of water [1] for the grinding and particle separation processes; most of it ends up being recirculated for reuse, slurry pumps are used after crushing and grinding feeding the ore to a classifier to separate fine-grained material (less than 5 mm) from coarse-grained material requiring further grinding. The lower ore grades [2] in the past couple of decades have demanded an increase on power size and efficiency of process machines to maintain a competitive plant throughput; Hydro-cyclone feed pumps to control both under and over milling or grinding are not the exception; Fig. 1 shows a conventional drive train [3] comprising an (1) asynchronous motor (also known as squirrel cage induction motor = SCIM), a high speed coupling (2), a gear reducer (3) and a low speed coupling (4) attached to the shaft of the pump (5), to accommodate the motor rated speed (typically 1800 rpm) to the process requirements (in the range of 250 rpm to 350 rpm), requiring additional components related to the gearbox: instrumentation, maintenance, disposable lubricants and filters, spare parts, thus reduces the overall system efficiency ultimately reflected into CAPEX and OPEX.WHY VARIABLE SPEED DRIVES FOR CYCLONE FEED PUMPS Hydrocyclones or commonly referred as “cyclones” are one of the most important devices in the minerals industry [4]; almost universally used in close-circuit grinding because of their high capacity and relative efficiency, the evolution of Power Electronics made affordable the use of Medium Voltage - Variable Frequency Converters (VFC) for Cyclone Feed pumps in combination with induction motors larger than 500hp (373kW) to gain multiple benefits: - Soft start with minimum electrical utility disturbance = inrush current mitigation - Full Torque available at zero speed for overload startup with pulp solidification after long still stand periods, superior to any other reduced voltage starting method. - Optimum and constant pump speed (independent of the electrical network or load condition), compared to across the line SCIM operation - Flexible Motor Voltage and Speed regardless of the power distribution Voltage and Frequency - Improved Power Factor (close to unitary), over the entire operating speed range"

Jan 1, 2015

By Baojie Zhang

The main goal of this study was not only to investigate the effectiveness of the FGX Dry Separator for removing pure rock from run-of-mine coal producing a better feed stock for conventional coal preparation plants but also to optimize the FGX Dry Separator performance for producing a salable clean coal product without using the conventional wet coal preparation processes. A Model FGX-1 Dry Separator with feed throughput capacity of 10 tph was extensively tested at the Illinois Coal Development Park using two coal samples having distinctly different cleaning characteristics. Statistically designed experimental programs were conducted to indentify critical process variables and optimize FGX Dry Separator performance by systematic adjustments of critical process variable parameters. The coal cleaning performance of the FGX Dry Separator was evaluated for the particle size range of 63.5 x 4.76 mm in most cases, although FGX Dry Separator feed consisted of nominal -63.5 mm run-of-mine coals. The best cleaning performance obtained from the FGX Dry Separator is described by specific gravity of separation (SG50) and probable error (Ep) values of 1.98 and 0.17, respectively. The SG50 and Ep values for individual size fractions were as follow: 1.90 and 0.12 for the +50.8 mm size fraction, 1.95 and 0.18 for the 50.8 x 25.4 mm size fraction, 2.01 and 0.19 for the 25.4 x 12.7 mm size fraction, and 2.03 and 0.23 for the 12.7 x 4.76 mm size fraction. These process efficiency measures produced a clean coal with ash content of 13.38% from a feed coal with ash content of 34.45%. Ash content of tailings and middlings streams were 85.09% and 39.57%, respectively. Total sulfur contents of corresponding streams were 3.87%, 4.68%, 6.87%, and 4.62%. For a relatively easy to clean Illinois No 6 seam coal (Cleaning Index: 0.72), only about 0.42% of the clean coal (i.e., 1.6 float fraction) present in the feed was lost to the tailings stream. For a relatively difficult to clean coal (Cleaning Index: 0.53), about 0.98% of the clean coal present in the feed was lost to the tailings stream.

Jan 1, 2012

By Abdelaziz Baçaoui, Imane Aarab, Abdelrani Yaacoubi, Khalid El Amari, Abderahman Etahiri

Phosphate ores upgraded by flotation are widely used as vital raw materials for the sustainable production of phosphate fertilizers to maintain the food supply. High-grade phosphate reserves become more and more depleted. Low-grade phosphate mining and processing are in the spotlight of the fertilizer industries to cope with the exponential growth in the world’s population and meet the increased demand for fertilizers. As part of a series of research works conducted within a major project aiming at upgrading a low-grade phosphate ore never-exploited before, the present work endeavors to optimize the flotation of this ore using the response surface method (RSM) as a follow-up of a screening study. Unveiling new insights on such a strategy paved the way for improving flotation performances. This work demonstrated that an optimum 30.18% P2O5 with 88.07% recovery was achieved using 63.10 g/t of sodium alginate (NaAL) and 2484.72 g/t of sodium oleate (NaOL) at pH 11.40. This maximum was contrasted with a new formulation of fatty acids (FAM). The 30.76% P2O5 grade with a recovery of 89.72% was attained using 50.94 g/t of NaAL and 1455.40 g/t of FAM at pH 11.68. FAM collector markedly outperformed NaOL at low concentrations proving the efficiency of synergists.

Dec 7, 2022