Mineral Processing Plants Research Articles

Recent Progress on Data-Based Optimization for Mineral Processing Plants

Abstract In the globalized market environment, increasingly significant economic and environmental factors within complex industrial plants impose importance on the optimization of global production indices; such optimization includes improvements in production efficiency, product quality, and yield, along with reductions of energy and resource usage. This paper briefly overviews recent progress in data-driven hybrid intelligence optimization methods and technologies in improving the performance of global production indices in mineral processing. First, we provide the problem description. Next, we summarize recent progress in data-based optimization for mineral processing plants. This optimization consists of four layers: optimization of the target values for monthly global production indices, optimization of the target values for daily global production indices, optimization of the target values for operational indices, and automation systems for unit processes. We briefly overview recent progress in each of the different layers. Finally, we point out opportunities for future works in data-based optimization for mineral processing plants.

Audit industrial thickeners with new on-line instrumentation

A theory of sedimentation-consolidation evolved in the last decades of the 20th century and is accepted today by researchers worldwide. This theory provides a reliable method of thickener design, simulation and control. However, a process model, simple or sophisticated, empirical or phenomenological, is useful only if it is possible to determine, in an objective way, its experimental parameters. Although it is important for a mineral processing plant to perform periodical laboratory test to determine thickening parameters, and adjust the operation in this way, laboratory tests not always represent the behavior of the material in a thickener. Research workers at the University of Concepción developed new instrumentation, algorithms and software to determine the material properties of the thickener feed, such as settling velocity of the suspension and the compressibility of the sediment produced. Work was made in a major Chilean copper mineral processing plant to test the new instrumentation. In this paper, the auditing of one molybdenum thickener and a tailings thickener are presented using the two new online instrument.

Supervisory Fuzzy Expert Controller for Sag Mill Grinding Circuits: Sungun Copper Concentrator

ABSTRACTSuccessful control of Semi-Autogenous Grinding (SAG) mill circuits has been the subject of many researches and main concern of plant operators for years. Distributed Control Systems (DCS) have had some degree of success in the mineral processing circuits, but maintaining operation of a SAG mill on the “edge” of its full capacity is not easily achievable by DCS. Advanced control systems, however, are a relatively new opportunity to successful control of mineral processing plants. This article presents the basis of a supervisory fuzzy expert controller for SAG mill circuits. Although leading companies in control and automation have their own commercial packages, this supervisory controller is coded in Matlab using Mamdani method and is able to connect to plant lower level control system. In the proposed controller, fuzzy system calculates optimum set points to the plant DCS control loops, enabling them to change the manipulating parameters to reach the new set points. This controller was installed, tested and verified in a copper grinding circuit. Results showed 1.8% increase in mill throughput, 3% decrease in power draw and more stable feeding regime at the same time.

Chapter 27 Lead–zinc–silver deposits of Myanmar

Before 1960 the Pb–Zn–Ag mines in Myanmar were an important source of foreign exchange. Almost the entire output of lead and zinc came from the Bawdwin Mine which, before 1942, was ranked as the sixth-largest producer of lead in the world (Ministry of Mines 1970). In 1938 Myanmar's output of refined lead, zinc concentrates and silver was 76 590 tons, 65 928 tons and 6 230 000 ounces, respectively. By 1986 output levels had fallen to 5948 tons of lead, 7393 tons of zinc and 576 000 ounces of silver. These figures represent a dramatic decline in production from the Bawdwin Mine and Namtu Processing Plant, which Soe Win (1994) has considered to be due to the failure to identify new reserves and inadequate investment in mine facilities. In the past, the Namtu–Bawdwin mining complex produced refined silver, lead and zinc concentrates, copper matte, nickel speiss and antimonial lead. The rich sulphide ore, previously mined underground at Bawdwin and treated at Namtu, yielded a lead concentrate averaging 51.3% Pb, 14.1% Zn and 1.16% Cu and a zinc concentrate averaging 26.1% Zn and 18.1% Pb. Currently, the oxide ore (‘halo ore’) from the open pit only is processed at Bawdwin, to yield a concentrate averaging 41.73% Pb, 9.03% Zn and 3.06% Cu. The lower ore grades present a problem for the old Namtu smelter, which was designed for processing sulphide ore and requires lead concentrates to have a minimum content of 57% Pb with 10–15% Zn and 1–2% Cu. A new blast furnace has been installed capable of smelting lead concentrates as low as 40% Pb, with a tolerance of up to 8% Zn and 3% Cu and with a rated capacity of 50 tons/day (Than Htay 2002). In addition, a zinc fuming plant will produce zinc oxide from zinc slags. …

Выявление возможности использования магнезиальных отходов ГОК для производства вяжущих

Выявление возможности использования магнезиальных отходов ГОК для производства вяжущих

Контроль и управление качеством рудопотоков железорудных горно-обогатительных комбинатов

Контроль и управление качеством рудопотоков железорудных горно-обогатительных комбинатов

Separation of colemanite from tailings using the pilot scale flotation column

The tailing discharged in mineral processing plants is not only an economical loss, but also an environmental problem in mining industry. For example, fine grained tailing of Emet Boron Concentrator in Kutahya/Turkey is discharged to the slurry pond. However, the B2O3 content of the tailing is about 26%, and therefore, it can be accepted as a valuable boron source after the determination of suitable method/methods to recycle these tailings. In this context, this study was aimed to utilize a column flotation technique to recycle the colemanite tailings after scrubbing-classification process. The effect of some operational parameters such as bias factor and superficial gas velocity was investigated on column flotation of colemanite in terms of recovery and grade. According to the results, a concentrate having nearly 45% B2O3 with a recovery of 99% was obtained from the tailings sample with 26% B2O3 using the flotation column. Finally, a colemanite concentrate of 43.12% B2O3 was produced with a recovery of 93.46% using scrubbing-classification followed by flotation processes.

Structural break detection method based on the Adaptive Regression Splines technique

For many real data, long term observation consists of different processes that coexist or occur one after the other. Those processes very often exhibit different statistical properties and thus before the further analysis the observed data should be segmented. This problem one can find in different applications and therefore new segmentation techniques have been appeared in the literature during last years. In this paper we propose a new method of time series segmentation, i.e. extraction from the analysed vector of observations homogeneous parts with similar behaviour. This method is based on the absolute deviation about the median of the signal and is an extension of the previously proposed techniques also based on the simple statistics. In this paper we introduce the method of structural break point detection which is based on the Adaptive Regression Splines technique, one of the form of regression analysis. Moreover we propose also the statistical test which allows testing hypothesis of behaviour related to different regimes. First, the methodology we apply to the simulated signals with different distributions in order to show the effectiveness of the new technique. Next, in the application part we analyse the real data set that represents the vibration signal from a heavy duty crusher used in a mineral processing plant.

Process effluents and mine tailings: sources, effects and management and role of nanotechnology

Increasing population levels, growing economies, rapid urbanization and changes in consumption patterns have increased the demand for raw materials such as base and precious metals, leading to growing concerns regarding their availability and the global efficiency of the mine supply chain. Mine tailings, consisting of process effluents that are generated in a mineral processing plant, are generally transferred to tailings ponds/impoundments to meet environmental regulations and site-specific factors before discharge. Most mining activities induce an impact on their geochemical environment (e.g., water, groundwater) due to the presence of metal-rich tailing deposits. The need for a comprehensive framework for mine tailings management that promotes sustainable development is therefore becoming increasingly recognized by the mining industry. Therefore, for sustainable rehabilitation and disposal of mining waste, the sources and mechanisms of pollutant generation and their subsequent effect on environment and sustainable treatment methods are critical. This review includes information on different sources of mining waters and its effect on groundwater contamination and ecological effects. The review also encompasses a broad range of mine water treatment strategies available for innovative management of mining tailings with a specific emphasis on the role of nanoparticles in the management of mine waters.

The use of the emulsion liquid membrane technique to remove copper ions from aqueous systems using statistical experimental design

Process water from mineral processing plants may contain a significant amount of dissolved metal ions, which may be recycled as process water, or discharged into the environment as effluent. If they are discharged into the environment they may cause significant problems for the local flora and fauna. One method of removing metal ions from aqueous systems, which has generated considerable interest over recent years, is the emulsion liquid membrane (ELM) technique, which incorporates solvent extraction and stripping. This work details the use of design of experiments applied to an ELM process for removing copper ions from a dilute aqueous solution. Initially, a fractional factorial design was used to screen out the most important factors; this was followed by a central composite design to obtain optimal operating conditions. The extraction percentage of copper was obtained as more than 99% under these conditions.

Optimal Estimation of Mass Partition in a Centrifugal Separator by Metallurgical Balance

Mineral processing plants make use of several types of equipments for size separation (size classification) to segregate ore particles by size. A particular type of such equipments is the centrifugal separator, which is intended to receive an input stream of ore slurry to be partitioned into two output streams: a coarse and a fines one. The coarse stream contains most of the coarse solids particles of the slurry, whereas the fines stream contains most of the fine particles. Although a centrifugal separator intends to perform a physical segregation of the solids particles by their size, a chemical segregation also results, in such a way that the chemical content of the coarse and the fines streams are normally different from the content of the input stream. When evaluating the performance of the separation process, three fundamental aspects should be analyzed: 1) the size distribution of the solids particles in each stream; 2) the amount of solids mass from the input stream that goes to the coarse stream and to the fines stream, that is, the mass partition; and 3) the chemical content of each stream. This work presents the application of the Least Squares method of optimization to calculate the mass partition, based on the measured chemical content of the streams, and on the metallurgical balance equations of the separation process.

Rheological characteristics of mixed kaolin–sand slurry, impacts of pH, temperature, solid concentration and kaolin–sand mixing ratio

Significant amount of slurry waste is produced from mineral processing plants globally constituting high levels of both kaolin and sand in aqueous suspension. Large quantities of slurry and mine tailings require efficient handling, transportation and storage system. The transportation and treatment of kaolin–sand slurry is dependent on its rheological behaviour which is a function of temperature, total solid concentration and pH. In this study, the effects of total solid concentration, pH and temperature on rheological behaviour of kaolin–sand mixture were investigated. These parameters were varied to analyse the viscosity, yield stress, flow index and shear force requirements of the mixed kaolin–sand suspension as a function of these varying parameters. Experimental rheological investigation conducted on rotational stress-controlled rheometer equipped with Peltier concentric cylinder system showed that the kaolin–sand mixture suspension is shear thickening in nature. The shear stress-rate rheograms for the kaolin–sand suspension can be modelled by the Herschel–Bulkley model with high levels of accuracy for pH range of 4–11, temperature range of 20–50 °C and solid concentration of 5–50 %. Solid concentration of the suspension was found to significantly affect the rheological behaviour of the mixture where higher kaolin–sand slurry concentration resulted in greater viscosity and the trend becoming less predictable for solid concentration greater than 50 % by weight. pH was another factor affecting the rheological behaviour of kaolin–sand slurry. pH of 3 or less resulted in the dramatic increase of viscosity of the suspension possibly due to the isoelectric point of the mixture system found between pH of 3 and 4.

Quantifying system disturbance and recovery from historical mining-derived metal contamination at Brotherswater, northwest England

Metal ore extraction in historical times has left a legacy of severe contamination in aquatic ecosystems around the world. In the UK, nationwide surveys of present-day pollution discharged from abandoned mines are ongoing but few assessments of the magnitude of contamination and impacts that arose during historical metal mining have been made. We report one of the first multi-centennial records of lead (Pb), zinc (Zn) and copper (Cu) fluxes into a lake (Brotherswater, northwest England) from point-sources in its catchment (Hartsop Hall Mine and Hogget Gill processing plant) and calculate basin-scale inventories of those metals. The pre-mining baseline for metal contamination has been established using sediment cores spanning the past 1500 years and contemporary material obtained through sediment trapping. These data enabled the impact of 250 years of local, small-scale mining (1696–1942) to be quantified and an assessment of the trajectory towards system recovery to be made. The geochemical stratigraphy displayed in twelve sediment cores show strong correspondence to the documented history of metal mining and processing in the catchment. The initial onset in 1696 was detected, peak Pb concentrations (>10,000 µg g−1) and flux (39.4 g m−2 year−1) corresponded to the most intensive mining episode (1863–1871) and twentieth century technological enhancements were reflected as a more muted sedimentary imprint. After careful evaluation, we used these markers to augment a Bayesian age-depth model of the independent geochronology obtained using radioisotope dating (14C, 210Pb, 137Cs and 241Am). Total inventories of Pb, Zn and Cu for the lake basin during the period of active mining were 15,415, 5897 and 363 kg, respectively. The post-mining trajectories for Pb and Zn project a return to pre-mining levels within 54–128 years for Pb and 75–187 years for Zn, although future remobilisation of metal-enriched catchment soils and floodplain sediments could perturb this recovery. We present a transferable paleolimnological approach that highlights flux-based assessments are vital to accurately establish the baseline, impact and trajectory of mining-derived contamination for a lake catchment.

Changes in the fingerprint of oil derived substances in the sediments of the Bílina River

The aim of this study was to evaluate the changes in the presence of the crude oil derived substances in the Bilina River sediments and to verify explanatory abilities of the used analytical methods. The Bi­lina River has its source on the slopes of Krusne hory and flows to the east through surface pits in an artificial corridor in its upper stream and further continues through the open landscape of the North Bohemian brown coal basin. The primary factor determining the current appearance of the landscape is human activity and anthropogenic embankments. The area along the Bi­lina River is loaded by the opencast brown coal mining and coal processing, petroleum refineries, and chemical plants. There are major industrial operations in the basin of the River Bi­lina which are particularly co-responsible over a long term for high levels of persistent organic pollutants and inorganic pollutants in the river sediments. Twenty samples of river sediments were collected along the Bi­lina River. All samples were subjected to the determination of the total extractable hydrocarbons, the total organic carbon, the total sulphur, and the sum of the polycyclic aromatic hydrocarbons(PAH). According to Herron (1988) most of the analysed samples belong to the shales or Fe-shales where a great possibility of sorption of inorganic or organic pollutants is expected. To distinguish the river segments with the prevailing input of the petrogenic from pyrogenic substances, correlation of the total extractable hydrocarbons and PAH were applied. The ratio fluoranthen / pyren, whose value from the anthropogenically modified flow in the segment Zaluži - Bi­lina did not go beyond 0.5 which is significant for the presence of the emissions from the transport or the petroleum industry, has been proved superior to the other currently recommended ratios of PAH. The evaluation of the archival TEH data did not show any improvement of the water and sediment quality along the Bi­lina river profile.

The entrainment effect on the performance of iron ore reverse flotation

An iron ore mineral processing plant in Brazil treating Itabirite ore was assessed by sampling a circuit consisting of Wemco 144 mechanical cells, as part of the AMIRA P9P collaborative research project. This paper presents and discusses the results of entrainability, water recovery and quartz and hematite grades associated to hydrodynamic parameters. The results indicated strong correlation between water recovery and hematite losses which was intensified by the operating conditions of the circuit.A potential alternative to reduce the hematite losses through entrainment and to increase quartz removal was to modify the traditional circuit design to treat rougher and cleaner/recleaner tails in different stages. In addition, the scavenger residence time must be matched to the quartz floatability. Changes to design and operation of these circuits are needed to sustain concentrate recovery and grade as iron ores become finer.

Dynamic simulation of tailing thickener at the Tabas coal washing plant using the phenomenological model

Real time dynamic simulation provides a powerful tool to control the mineral processing plants with the minimum cost. In this study, the dynamic simulation was carried out for the thickener at coal washing plant. Therefore, the parameters of the phenomenological model for the sedimentation and thickening were determined at different conditions. Dynamic simulation was carried out for each condition and the effect of feed flow rate variations on solid volume fraction of the thickener underflow and bed height was investigated. For all conditions, it was observed that when feed flow rate increases, the solid volume fraction of discharge and bed height increase. It was also observed that, in the case of the flocculated suspension, the maximum solid volume fraction of the thickener underflow decreases and the bed height increases with pH reduction, for two size fractions. Also, the maximum solid volume fraction of the thickener underflow for d80=275μm is higher than that of d80=125μm and the height of compression zone for d80=125μm is higher than that of d80=275μm at the certain pH and flocculant dosages.

Data-Based Multiobjective Plant-Wide Performance Optimization of Industrial Processes Under Dynamic Environments

This paper provides a method for automatically selecting optimal operational indices for unit processes in an industrial plant using measured data and without knowing dynamical models of the unit process. A dynamic multiobjective optimization problem is defined to find operational indices that lead to plant-wide production indices close to their target values. A case-based reasoning (CBR) technique is also employed, which uses the stored experience of a human expert to determine appropriate operational indices for given target production indices. The solutions of the optimization problem and CBR technique are combined to form baseline operational indices. The dynamic models of the production indices, however, are time varying and affected by disturbances and online corrections of these baseline operational indices are required. To this end, reinforcement learning (RL) is used to provide a data-driven optimization technique to compensate for disturbances and model approximation errors and variations. The data-driven RL approach is used in two different time scales. The samples of the predicted production indices are used at a fast sampling rate, i.e., at each sample time, and the samples of actual production indices are used at a slower sampling rate, i.e., after each operational run, to correct the baseline operational indices. The effectiveness of this automated decision procedure has been demonstrated by successful implementation of the proposed approach on a large mineral processing plant in Gansu Province, China.

Failure rate analysis of jaw crusher using Weibull model

The primary crusher is essential equipment employed for comminuting the mineral in processing plants. Any kind of failure of its components will accordingly hinder the performance of the plant. Therefore, to minimize sudden failures, analysis should be undertaken to improve performance and operational reliability of the crushers and its components. This paper considers the methods for analyzing failure rates of a jaw crusher and its critical components application of a two-parameter Weibull distribution in a mineral processing plant fitted using statistical tests such as goodness of fit and maximum likelihood estimation. Monte Carlo simulation, analysis of variance, and artificial neural network are also applied. Two-parameter Weibull distribution is found to be the best fit distribution using Kolmogorov–Smirnov test. Maximum likelihood estimation method is used to find out the shape and scale parameter of two-parameter Weibull distribution. Monte Carlo simulation generates 40 numbers of shape parameters, scale parameters, and time. Further, 40 numbers of Weibull distribution parameters are evaluated to examine the failure rate, significant difference, and regression coefficient using ANOVA. Artificial neural network with back-propagation algorithm is used to determine R2 and is compared with analysis of variance.

Electrochemical Method of Technogenic Waters Demanganation

The research data are presented for ions of manganese(II) removal from technogenic waters of mining processing plants operating in the electromecanical field. These data are based on high adsorption capacity of electrogenerated coagulant, namely, aluminium hydrate in γ modification (gibbsite) that has the porous structure. Effectiveness of electromechanical treatment of technogenis waters aimed at removal ions of manganese(II) was at least 90 %.

Plant-wide control of grinding mill circuits: Top-down analysis

A generic top-down control structure is proposed for the optimal steady-state operation of a grinding mill circuit. The economic cost function of the grinding mill circuit is defined with reference to the final product of the larger mineral processing plant. A mineral processing plant in this study consists of a comminution and a separation circuit. The comminution circuit’s operational performance primarily depends on the mill’s performance. Since grindcurves define the operational performance range of a mill, the grindcurves are used to define the setpoints for the economic controlled variables for optimal steady-state operation. For a given metal price, processing cost, and transportation cost, the proposed structure can be used to define the optimal operating region of a grinding mill circuit for the best economic return of the mineral processing plant.