Mineral Processing Plants Research Articles

Optimized product quality control at Kola MMC’s mineral processing plant

Kola MMC’s Mineral Processing Plant has optimized its product quality control system designed to monitor the mass concentration of non-ferrous metals in the commercial products: i.e. the finished concentrate and the final tailings. Thus, automatic samplers and dividers of Sections 1, 2 and 3 have been made fully conforming with GOST 14180–80; through experiments, variation coefficients have been determined, which were used to specify the homogeneity class for the concentrate and the tailings; operating parameters have been defined for the sampling and sample preparation equipment; through experiments, intermediate precision mean square deviations (Sопр) and intermediate precision limits (RLопр) have been determined. Measurement procedures have been developed that were certified by Rosstandart, Russia’s Federal Agency for Technical Control and Metrology.

Pengaruh Temperatur, Komposisi Bahan Cangkang Inti Kelapa Sawit dan Konsentrasi Perekat pada Karakteristik Briket Komersial dari Tempurung Kelapa Sawit

Briquettes are an essential product for metal mineral processing plants in Indonesia. One good alternative raw materials for briquettes that do not pollute the environment is the palm kernel shell. This research was conducted by making briquettes from palm kernel shells to find optimal variations in carbonization temperature, material mixture, and adhesive mixture. The research was conducted on a laboratory scale. The palm kernel shell and coal kernel were carbonized at various temperatures, namely 450°C, 550°C, and 650°C, then crushed and sieved to 35 mesh. The powdered palm kernel shell and coal that have become powdered charcoal are weighted based on a mixture of powder and the adhesive composition ratio of 40 g. After that, the briquettes were formed under a pressure of 100 kg/cm² on a cylindrical mold with 40 mm. The analyzes carried out were moisture content, ash content, volatile substances content, fixed carbon content, calorific value, compressive strength, density, porosity, and SEM (Scanning Electron Microscope). The results showed that the briquette from the kernel of the palm kernel shell was optimal at a temperature of 550 ° C with a starch adhesive mixture of 7.5%, a pressure of 100 kg/cm², moisture content of 5.34%, an ash content of 5.81%, a substance content. Volatile amounted to 18.77%, 71.08% for fixed carbon, heating value 7125.86 cal/g. Density of 0.78, porosity of 0.04 and strength of 72.56 kg / cm².

Intelligent dry fog dust suppression system: an efficient technique for controlling air pollution in the mineral processing plant

Dust suppression system plays a significant role in mining and allied industries. It has become an integral part of the environmental management system. Dust emission from mining and mineral processing industries poses environmental and health problems to workers and surrounding people. Dust creates a reliability issue in machinery and ventilation systems, causing infrastructural damage and the industry’s financial losses. This paper deals with a smart dry fog dust suppression system which has been developed for effectively controlling dust emission from mining and mineral processing activities. The system has been implemented in an iron ore crushing and screening plant in India, and its efficacy has been evaluated for controlling dust emission. The installed dry fog system reduced dust concentration to 0.10–0.17 mg m−3 from the prevailing dust concentration of 0.62–1.73 mg m−3 in work zone areas, which was much below the permissible limit below 1 mg m−3 where silica content in the dust was less than 5%. Percentage of free silica in the work zone dust reduced to traces from 3.61 to 4.80%. Similarly, PM10 and PM2.5 concentrations in the ambient air were decreased to 90–99 μg m−3 and 49–58 μg m−3 from 185 to 250 μg m−3 and 148–200 μg m−3, respectively. Further, concentrations of PM10 and PM2.5 were drastically reduced by 51.35–60.4% and 69.69–71.0%, respectively. The reduced dust concentrations in the ambient air were within the prescribed limit of PM10 (100 μg m−3) and PM2.5 (60 μg m−3). The system significantly reduces dust and free silica concentration in the work zone areas below the permissible limit. The system controls dust emission with an increase in production as it has been found that the number of nozzles is directly correlated with a reduction in dust. Furthermore, the system does not change the raw material’s mass as water added to dust is less than 0.01% of the raw material. The system is designed to give the best results within the closed environment of the plant. The system helps in eco-friendly and clean mining. The system reduces the breakdown and maintenance cost of mining equipment, thereby decreasing overall operating costs. Further, the system minimizes mine workers’ health problems, like silicosis and severe other occupation diseases. The system is automatic, cost-effective, energy efficient, and easy to maintain. Further, the system is capable of handling dust problems in the closed environment of crushing and screening plants. These properties make the system techno-economically feasible for installation in mineral processing plants.

Repurposing legacy metallurgical data part II: Case studies of plant performance optimisation and process simulation

The history of the metallurgical industry is rich with data. An enormous amount of data is generated from mining operations and industrial factories, and as deployment of new technologies such as on-line monitoring and in-situ instrumentation proliferate through the 4th industrial revolution, the quantity and quality of data will increase dramatically. The first paper (Part I), describes a range of promising technologies that integrate well with existing mineral processing plants and testing laboratories to demonstrate the enormous potential of a dry laboratory. A dry lab is a type of laboratory that includes applied or computational mathematical analyses for an extensive range of different applications. In both laboratories and mineral processing plants, integration of timely, accurate and reliable data analytics is key to leveraging data to enable data-driven plant design, optimisation and monitoring. However and despite progresses in analytical technology and increasing availability of data and sophisticated data analytics, legacy metallurgical plant and test work data are being underutilised. Understanding the insights contained within legacy metallurgical plant data is critical to the transition into a data- and analytics-driven industry. This paper (Part II) details two case studies that use legacy data to benefit metallurgical processes. One case study focuses on operational data from a gold recovery plant and provide indirect knowledge of the structure and/or composition of the feed sources, and insights to guide the optimisation of the operation. The other case study focuses on laboratory flotation tests, and demonstrates the effectiveness of aggregated data in establishing empirical guidelines that can guide the design and optimisation of new and existing processing operations.

Green mining: technical study of off-shore tin mining using cutter suction dredger in Bangka Island, Indonesia

According to government regulations regarding good mining practice, PT Timah Tbk and its partners have begun to develop offshore mining techniques using Cutter Suction Dredger (CSD). Therefore there is a need for a technical study of the application of CSD in offshore tin mining. The method used in this research is to observe field activities directly. Observation of mining data of mining design, dredging system and mapping of bathymetri. The process flow, production and tin ore recovery of mineral processing. Observation of the tailings disposal considers the minimal impact on the environment. The result is mining design using CSD applies a long face system with a combination of vertical digging. The opening angle of the two anchors amounting to 90-145° produces width snee of 40-55 m. This method is capable of producing an average rate of soil removal of 250 m3/hour. The floating mineral processing plant uses a three-stage jigging method with Circullar and Pan American types plus a shaking table resulting a washing tin recovery of 66%-90%. Considering bathimetry, the geotube embankment technique can control the spread of tailings. The conclusion is that the mining process using CSD is one step better in terms of implementing good mining practice.

Challenges in the Assessment of Mining Process Water Quality

The changes in water quality owing to recirculation of water in mineral processing plants can compromise the plant performance as well as maintenance needs. Therefore, mining process water quality assessment is becoming critical. Nevertheless, very few studies have investigated the suitability of the current analysis methodology practiced in certified laboratories for evaluating mining process water quality. This article presents two case studies to highlight the major issues encountered when performing sampling for physicochemical and chemical parameters in process water at two European mine sites using procedures from two certified laboratories. In addition, microorganisms were shown to be abundant in process waters and likely affect the mining water chemistries. However, the protocols used for microbial studies are not optimal for mining process samples, and need to be improved. The results showed difficulties in providing satisfactory results when analyzing control samples. Additionally, the analysis results presented a strong imbalance in TDS and sulfur compounds. Several potential causes associated with the poor quality of the analysis results have been outlined with a specific focus on the preservation methods. A literature review on the degradation of thiosalts suggested that the current preservation procedures are not suitable for preserving sulfur compounds. Moreover, the results indicated that the water matrix strongly influenced the validity of the chosen analysis method. In conclusion, the analysis methods should be customized for the different mining water matrix types in order to ensure the accuracy and reproducibility of the results.

Hardness and chloride removal in dewatering system: Modeling and optimization of electrochemical reaction

The electrocoagulation (EC) process is a novel approach in the mining industry, especially to recycle water in the dewatering system of a mineral processing plant. In this research, the electrocoagulation process was studied to remove the hardness and chloride ions from concentrate thickener overflow water under different operating conditions: retention time (5–15 min), initial pH (4–10), current density (41.6–166.6 A/m2) and electrode type (Fe, Fe-Al, Al). Four factors with three levels with the D-optimal response surface design were applied for optimization. As a result, the optimal situation for the electrocoagulation process was characterized by a retention time of 15 min, initial pH of 9.08, the current density of 139.59 A/m2, and electrode type Fe-Al. In this situation, the maximum removal efficiency of hardness (60.11%) and chloride (98.38%) were yielded with a desirability value of 0.989. These results illustrated the effectiveness of the EC process as an influence method for the removal of hardness and chloride in terms of separation.

Effect of Eh and pH on the flotation of enargite using seawater

The presence of enargite in porphyry-copper deposits is an important matter as this sulfosalt displays good floatability in the presence of the collectors which are usually used in the flotation of copper sulfides, thus it readily floats and contaminate the copper concentrates. Scarcity of water resources is a relevant problem in the Chilean mining industry and the use of seawater in the mineral processing plants is today a feasible solution. The flotation behaviors of copper sulfides and molybdenite in seawater was studied to some extent, but the enargite behavior in this aqueous medium has seldom been investigated. The objective of this work was to study the flotation behavior of enargite in seawater under different pulp electrochemical potentials (Eh) and pH. The independent effects of calcium and magnesium were also evaluated. The experimental results show that enargite flotation in seawater is depressed at both reducing and oxidizing conditions at pH = 9. At pH = 10.5 enargite is strongly depressed to values even below 20% at the whole range of Eh studied which may be explained by the adhesion of magnesium hydroxo-complexes to the enargite surfaces rendering it hydrophilic. The depressing effect of calcium on enargite flotation is stronger than the depressing effect of magnesium, although calcium concentration in seawater is lower. This conclusion may be related to the presence of highly stable compounds such as hydrophilic calcium arsenates on the enargite surface.

Dissolution Test Protocol for Estimating Water Quality Changes in Minerals Processing Plants Operating With Closed Water Circulation

To save freshwater resources and comply with environmental regulations, minerals processing operations are transitioning to partially or fully closed water circulation. However, the accumulation of electrolytes and the addition of reagents lead to changes in water composition and may compromise flotation performance and plant maintenance. As a consequence, costly modifications are often required to cope with these challenges. Therefore, knowledge about water quality variation owing to closed water circulation and its potential effect on the flotation performance is crucial. The experimental methodology presented in this paper targeted three main objectives: (1) predicting the tendency of the accumulation of elements and compounds into the process water during comminution, flotation, and storage in tailings facilities; (2) establishing a relationship between laboratory results and plant historical water quality data; and (3) predicting the potential effect of recycling water on flotation performance. The results obtained with Boliden Kevitsa ore showed a good correlation between the water matrix of the actual process water on-site and that obtained in the ore dissolution tests done in the laboratory. The final water composition came close to the process water in terms of major elements and some of the minor elements. Additionally, the work presented in this paper demonstrated that a dissolution loop allowed us to predict the potential impact of the recycling water on the ore flotability. This methodology could serve as an aid for predicting water quality matrix variation and designing closed water circulation systems at existing and new plants.

мPhysiological Assessment of Miners’ Noise Exposure and Measures for Its Prevention

Introduction: To solve the tasks of preventing occupational diseases in workers of the mining industry, it is important to substantiate physiological indicators of tension of the regulatory systems of the human body under the negative impact of industrial noise and neuro-emotional work intensity and to assess the effectiveness of hearing personal protective equipment (PPE). Our objective was to identify physiological characteristics of adverse functional changes in workers of various professions in the mining industry exposed to the combined effect of occupational noise and work intensity to substantiate the use of hearing protection devices. Materials and methods: We studied indicators of concentration of attention, short-term memory, speed of perception of visual and auditory signals, and the index of functional changes in the circulatory system reflecting negative effects of occupational noise exposure combined with work intensity on the central nervous and cardiovascular systems. We assessed occupational noise exposure by the equivalent sound level on the A-scale of a sound level meter per shift, work intensity, and conducted physiological studies of mining industry employees. Results: In miners, we established a 5.6-fold decrease in concentration of attention from the initial level and a 5.9-fold increase in the index of functional changes in the circulatory system compared with operators of robotic complexes, in which all indicators varied within the physiological norm. The maximum change in the parameters indicates the work tension that was the most pronounced in miners. The same extent of workplace stress was observed in operators of mineral processing plants and engineering and technical staff exposed to similar noise levels (60-70 dB, sometimes exceeding 90 dBA), while the lowest one was observed in the operators of robotic complexes, thus indicating maintenance of a sufficient level of working capacity during the work shift. The estimated miners’ index of functional changes in the circulatory system (2.69±0.08 points) demonstrated the state of functional stress. The individual analysis indicated a significant percentage of people with reduced unsatisfactory adaptation and the state of its failure (3.0±0.05 points) in this very professional group. According to the results of establishing a causal relationship between the increase in the functional tension by indicators of the central nervous system and cardiovascular system and occupational noise levels, emotional stress and adverse shift mode, the workplace stress was justified as a marker of the combined effect of noise and intensity of the work process. Conclusions: A high level of workplace stress accompanied by intensive occupational noise and work intensity factors is an indicator of a decreasing working capacity and development of a prognostically unfavorable functional state of the human body.

Reinforcement Learning Based Decision Making of Operational Indices in Process Industry Under Changing Environment

The plant-wide production process is composed of multiple unit processes, in which the operational indices of each unit process are assigned and adjusted according to product quality, yield, and actual operating modes. Due to the changing operational conditions of the production process, the operational indices cannot be effectively adjusted by most of the model-based methods or evolutionary computation. In this article, the decision making of operational indices is formulated as a continuous state, continuous action reinforcement learning (RL) problem and a model-free RL algorithm is proposed, which learns a decision policy to determine the operational indices according to the actual operational conditions. Different from the existing methods, this article presents a multiactor networks ensemble algorithm and an actor-critic framework with stochastic policy to avoid falling into local optimums. The relatively overall optimal policy is obtained by extracting the results of parallel training of multiactor networks, which guarantees the optimality of the obtained policy. In addition, by using the experience replay, it is particularly valuable to effectively deal with the problem that lacking of sampling data in the model-free RL. Simulation studies are conducted on actual data of a mineral processing plant and the results demonstrate the effectiveness of the proposed algorithm.

Effect of Holed Ferrum electrodes (HFE) on the efficiency of the electrocoagulation process for copper recovery and optimization of parameters, using RSM

The present study investigated the electrocoagulation (EC) process using holed Ferrum electrodes (HFE) in the mineral industries for copper recovery from the pregnant leach solution (PLS). To this end, the response surface methodology was used to optimize factors affecting copper recovery in the EC process. The Box-Behnken design was employed to optimize experiments and effects of four independent variables - including initial pH (X1), current density (X2), electrode distance (X3), and electrolysis time (X4) - were studied to investigate copper recovery. Moreover, a linear model was used to calculate the copper recovery rate. The most important independent variables and their interaction were evaluated using ANOVA. Optimal operating conditions with copper recovery were obtained at the initial pH of 5.2, current density of 438.2 mA/cm2, electrode distance of 2.10 cm, and electrolysis time of 68.05 min. The copper grade yield was above 90% that was shown by XRD and SEM-EDAX analyses. The results of the SEM-EDAX analysis indicated that the main elements contained in particles included copper (82.5%–90.4%), Fe (6.2%–8.6%), and O2 (3.4%–8.9%), respectively. Moreover, the results of XRD studies confirmed that the minerals formed in the studied samples were mostly classified into two main phases of copper and cuprite, and that the rare phase included quartz minerals. It is concluded that the EC process as a reliable method has highly desirable capability in the recovery of soluble copper and recycling of water from mineral industries, especially in mineral processing plants.

Isolation and removal of cyanide from tailing dams in gold processing plant using natural bitumen

Gilsonite as a natural occurrence of bitumen and due to the presence of carbon in its structure is a suitable adsorbent for a wide variety of pollutants. In this research, the adsorption of cyanide from the wastewater of gold processing plants using gilsonite were investigated. In this way, the effect of particle size of gilsonite, the weight and mixing time with solution, on the amount of cyanide adsorption have been studied. In addition, in one experiment, the effect of processed gilsonite on its adsorption ability was investigated. Based on the obtained results, the maximum adsorption of 61.64% was obtained in the size range of −1+0.5 and −2+1 mm of gilsonite. With increasing adsorbent weight and mixing time, the cyanide adsorption rate were increased. On the other hand, with the processing of the gilsonite sample, the amounts of adsorption were increased considerably. This study indicated that gilsonite can be used as an isolation and absorbent in the structure and floor of the tailing dumps of mineral processing plants.

Understanding Mineral Liberation during Crushing Using Grade-by-Size Analysis—A Case Study of the Penuota Sn-Ta Mineralization, Spain

Coarse comminution test-work and modeling are powerful tools in the design and optimization of mineral processing plants and provide information on energy consumption. Additional information on mineral liberation characteristics can be used for assessing the potential of pre-concentration stages or screens in the plant design. In ores of high-value metals (e.g., Ta, W), standard techniques—such as the mineralogical quantification of grain mounts by quantitative evaluation of minerals by scanning electron microscopy (QEMSCAN) or chemical analysis by X-ray fluorescence (XRF) can be challenging, due to the low relative abundance of such valuable minerals. The cost of QEMSCAN is also a limiting factor, especially considering the large number of samples required for the optimization of coarse comminution. In this study, we present an extended analytical protocol to a well-established mechanical test of interparticle breakage to improve the assessment of coarse mineral liberation characteristics. The liberation of ore minerals is a function of the rock texture and the difference in size and mechanical properties of the valuable minerals relative to gangue minerals and they may fraction in certain grain sizes if they behave differently during comminution. By analyzing the bulk-chemistry of the different grain size fractions produced after compressional testing, and by generating element by size diagrams, it is possible to understand the liberation characteristics of an ore. We show, based on a case study performed on a tantalum ore deposit, that element distribution can be used to study the influence of mechanical parameters on mineral liberation. This information can direct further mineralogical investigation and test work.

Toxic Metallic Trace Elements in Post-Delivery Mothers and their Newborns Residing near and far from Mining Operating Plants in Lubumbashi

Background: Worldwide, modern life is characterized by excess of toxicTE due to pollution (domestic and industrial waste) and reduced intake of essential TE, consequence of imbalanced diet. In the context of cases of environmental pollution by TE documented in the city for years, the purpose of this study was to determine blood concentrations of essential TE and correlation coefficients in post-delivery mothers and their newborns living 3km from the mining processing plants in the city of Lubumbashi, Congo. Method: Two prospective cohorts were formed based on distance between the home of the pregnant women and mineral processing plants ( 3km). Four TE (Cr, Cu, Se and Zn) were tested at the laboratory of the Congolese Control Office of Lubumbashi by ICP-OES in total blood samples of 378 post-delivery mothers and 378 newborns, voluntarily and consecutively recruited. Results: The difference in TE geometric means concentrations between the two cohorts (study population living 3km from the mining processing plants) was not significant (p>0.05).Our study showed excessive geometric means of Cr estimated at 4.86 µg/L in the post-delivery mothers and 5.03 µg/L in the newborns (RV: < 1 µg/L ), lower geometric means estimated at 218 µg/L in the post-delivery mothers for Cu ( RV:700-1500 µg/L) ;47.32 µg/L in the post-delivery mothers and 46.61µg/L in the newborns for Se (RV: < 142 µg/L ) ;419 µg/L in the post-delivery mothers and 384 µg/L in the newborns for Zn (RV: < 7270 µg/L ) but within normal range :215 µg/L in the newborns for Cu (RV: 90-460 µg/L).This was confirmed by their respective bioaccumulation factors. The correlation coefficient between TE concentration of the post-delivery mothers and their newborns was positive but statistically significant for Cu, Se and Zn (p<0.05). Conclusion: Our study has noticed low geometric means of the concentrations of Cu, Se and Zn in total blood of post-delivery mothers and their newborns living 3 km from the mining operating plants with no statistical difference between the two cohorts along with bioaccumulation factor <1. We also found excessive geometric mean for Cr. These findings hence the importance of an early diagnosis and intervention of marginal TE status. Analysis of determinants of the essential TE bioaccumulation and their impact on maternal and neonatal morbidity should be purpose of future studies.

Effects of Flocculant, Surfactant, Coagulant, and Filter Aid on Efficiency of Filtration Processing of Copper Concentrate: Mechanism and Optimization

In the recent decades, water scarcity has become a major challenge for many reasons, especially the inadequate use of water resources. The mineral processing plant is among the most important water-consuming industries. Filtration, as one of the important processes in water recovery, is a process in which the solid-suspended particles are removed from the liquid. In the present work, the effect of the additives affecting the filtration process upon the responses including the resistance to filter cloth (R), specific cake resistance (α), moisture content, water recovery rate, and cake formation rate by the vacuum top-feed method is investigated. The experiments are performed by two methodologies: one-factor-at-a-time and statistical analysis. The additives are the flocculant, coagulant, surfactant, and filter aid. According to the one-factor-at-a-time methodology, the optimal type and dosage of the variables are as follow: flocculant A25 with a concentration of 15 g/L, perlite as the filter aid with an amount of 2.5%, surfactant cop 20-101 with a concentration of 3 cc/L, and the coagulant CaCl2.2H­2O with a concentration of 2.5 g/L. The usage of the flocculant, surfactant, and filter aid at the same time is also statistically analyzed with the aim of maximizing the cake formation rate and minimizing the moisture content of the filter cake. Under the optimal conditions and taking into account 11.68 g/t of the flocculant A25, 3.8% of perlite as the filter aid, and2.92 cc/L of the surfactant cop 20-101, the cake formation rate and the moisture content were obtained to be 0.297 mm/s and 12.7 %, respectively.

Essential Metallic Trace Elements in Post-Delivery Mothers and their Newborns Residing Near and Far from Mining Operating Plants in Lubumbashi

Background: Worldwide, modern life is characterized by excess of toxicTE due to pollution (domestic and industrial waste) and reduced intake of essential TE, consequence of imbalanced diet. In the context of cases of environmental pollution by TE documented in the city for years, the purpose of this study was to determine blood concentrations of essential TE and correlation coefficients in post-delivery mothers and their newborns living < of 3km and >3km from the mining processing plants in the city of Lubumbashi, Congo.

Analysis of mechanical equipment failure at the hard coal mine processing plant

Analysis of mechanical equipment failure at the hard coal mine processing plant

Analysis of mechanical equipment failure at the hard coal mine processing plant

Analysis of mechanical equipment failure at the hard coal mine processing plant

Power-draw prediction by random forest based on operating parameters for an industrial ball mill

Estimation of mill power-draw can play a critical role in economics, operation and control standpoints of the entire mineral processing plants since the cost of milling is the single biggest expense within the process. Thus, several empirical power-draw prediction models have been generated based on a combination of laboratory, pilot and full-scale measurements of different milling conditions. However, they cannot be used in industrial plants, where in full-scale operations, only not few numbers of input parameters used in those models are measured. Moreover, empirical models do not assess the relationship between input features. This investigation is going to introduce random forest (RF), as a predictive model, beside of its associated variable importance measures system, as a sensible means for variable selection, to overcome drawbacks of empirical models. Although RF as a powerful modeling tool has been used in several problem solving systems, it has not comprehensively considered in the powder technology areas. In this investigation, an industrial ball mill database from Chadormalu iron ore processing plant were used to develop a RF model and explore relationships between power-draw and other monitored operating parameters. Modeling results indicated that RF can highly improve the prediction accuracy of power-draw as compared to the regression as a typical method (R2: 0.98 vs. 0.60, respectively) and rank operational milling parameters based on their importance.