Ore Quality Research Articles

Economic Expediency of Copper Ore Mining with Waste Rock Fill of Secondary Stopes in the West Wing of the Oktyabrsky Deposit

The economic expediency of developing the west wing reserves of Oktyabrsky Mine by cutand-fill method with cemented backfill of primary stopes and waste rock fill of secondary stopes has been determined. This method shows better performance in terms of ore loss and dilution as compared with the current mining system at the same quality of ore produced. Feasibility study of two variants of process design in the full cycle of mining, processing and recovery of primary metal (nickel) and associated metals (copper, platinum, etc.) shows that the proposed mining system allows higher profit per unit of ore mining and processing.

Predicting iron ore sinter strength through partial least square regression (PLSR) analysis of X-ray diffraction patterns

The decrease in quality of Australian iron ore, coupled with the demand for more efficient energy use, means that closer monitoring and optimisation of process conditions for iron ore sinter production is required. Here, the suitability of using partial least-squares regression analysis of powder X-ray diffraction data, collected for iron ore sinter samples, for the prediction of iron ore sinter strength has been further assessed. In addition, a preliminary assessment of the effect of 2θrange on the quality of prediction has been made. For the purposes of process control, the level of correlation between predicted strength and actual sinter strength would inform an operator whether or not the process was operating within the acceptable limits, or whether there was a potential problem requiring further investigation or rapid intervention. Reducing the 2θrange was found to reduce the level of correlation between predicted and actual strength, to a point where the particular analysis may no longer be suitable for process control.

Modified acid–base accounting model validation and pH buffer trend characterisation in mine drainage at the AngloGold Ashanti Obuasi mine in Ghana, West Africa

Acid–base accounting (ABA) is a static test used to evaluate pre-mining drainage quality of ores with interpretations based on a reference 3-data point model. The method is often complemented with a kinetic test to ensure certainty of results. The challenges associated with both methods compel companies to rely on only the ABA test, thereby compromising on the long-term drainage quality. This paper validates a proposed 4-data point model that was used to establish a 20% increase in the alkaline amendment of ores at the AngloGold Ashanti Obuasi Mine in Ghana. The validation was done using model limits, the robustness of coefficient of determination and model factor sequence variation. Acidification trends and mineralogical data evaluation of tailings were used to characterise pH buffer trends in mine drainage. The modified 4-data point model, which incorporates a vital kinetic test factor into the ABA model, provides a criterion for the adjustment of carbonate amendment value to improve acid neutralisation in the drainage; this would reduce (1) cost of experimentation, (2) turnaround time for analyses, (3) complexities associated with both test methods. From the XRD data, alunite and goethite are present in tailings to provide sustained pH buffering in drainage beyond the scope of the modified model, while the characterised pH buffer trend could be used for monitoring drainage quality.

Applications of bauxite residue: A mini-review.

Bauxite residue is the waste generated during alumina production by Bayer's process. The amount of bauxite residue (40-50 wt%) generated depends on the quality of bauxite ore used for the processing. High alkalinity and high caustic content in bauxite residue causes environmental risk for fertile soil and ground water contamination. The caustic (NaOH) content in bauxite residue leads to human health risks, like dermal problems and irritation to eyes. Moreover, disposal of bauxite residue requires a large area; such problems can only be minimised by utilising bauxite residue effectively. For two decades, bauxite residue has been used as a binder in cement industries and filler/reinforcement for composite materials in the automobile industry. Valuable metals and oxides, like alumina (Al2O3), titanium oxide (TiO2) and iron oxide Fe2O3, were extracted from bauxite residue to reduce waste. Bauxite residue was utilised in construction and structure industries to make geopolymers. It was also used in the making of glass-ceramics and a coating material. Recently bauxite residue has been utilised to extract rare earth elements like scandium (Sc), yttrium (Y), lanthanum (La), cerium (Ce), neodymium (Nd) and dysprosium (Dy). In this review article, the mineralogical characteristics of bauxite residue are summarised and current progresses on utilisation of bauxite residue in different fields of science and engineering are presented in detail.

Lithological classification and chemical component estimation based on the visual features of crushed rock samples

Lithological classification and monitoring of ore quality are challenging issues in mine operation, especially to maintain desired feed for processing minerals plants. Quantification of visual features is an innovative method to analyze rock components. In this paper, an analysis of vision-based rock type and classification algorithm is proposed for fast, inexpensive, and reliable identification process compared with common chemical analysis. To evaluate the proposed algorithm, samples were collected from the Novin limestone mine in Iran. Based on chemical and thin-section studies, the samples were classified into three different groups as calcium carbonate, dolomite, and dolomitic limestone. The limestone samples were crushed, sieved, and, respectively, divided into three size fractions as 2.5–7, 1.5–2.5, and 0.1–1.5 cm. A set of 58 images as large and medium size samples and 78 images as fine size samples were taken in the laboratory environment. Features were extracted from the captured images and reduced by applying principal component analysis (PCA). The support vector machine (SVM) and Bayesian techniques were used for classification. The best classification accuracy was about 80 and 90% in limestone and dolomite rock samples, respectively. Then, a multi-layer perceptron (MLP) neural network was employed to predict chemical compositions percentages. The determination coefficient within the range of 0.76 to 0.85 was observed and predicted values confirmed good performance of the grade estimation. The outputs illustrated that the proposed intelligent and automated technique can be successfully applied to monitor ore grade and classify lithology in different stages of mining projects.

Beneficiation of coarse particulate iron ore by using a dry density-based fluidized bed separator

A dry density-based fluidized bed separator was used to beneficiate coarse particulate iron ore. The atomized iron powder and zircon sand, with specific size fractions of 150–75 and 250–150μm, were mixed in certain proportion to form a binary dense media. The results indicated that the binary dense media efficiently formed stable fluidization within the fluidized bed for subsequent separation of iron ore particles. The theoretical separation density of 3.5–4.0g/cm3 was determined by investigating the relationships among particle size, density distribution, and total Fe-grade in the iron ore sample. The effects of static bed height, operational gas velocity, and weight proportion of the atomized iron powder in the binary dense media on the stability of bed density were studied to determine the appropriate operational conditions. The stability of bed density was maintained under the condition with a static bed height of 80–90mm, an operational gas velocity of 1.6–2.0Umf, and a weight proportion of the atomized iron powder in the binary dense media of 90%. The effects of static bed height, gas velocity, and size fraction of iron ore particles on the dry separation efficiency were also investigated to determine the optimum separation performance. The optimum total Fe-grade and satisfactory recovery were achieved at appropriate static bed height and gas velocity. The separation efficiency of coarse iron ore particles gradually decreased with decreasing size fraction. This study aims to provide an alternative approach for improving the quality of coarse particulate iron ore.

3D geostatistical modelling for identifying sinkhole disaster potential zones around the Verkhnekamskoye potash deposit (Russia)

This work results from a cooperative scientific program between the Perm State University (Russia) and the University of Lorraine (France). Its objectives are to integrate modern 3D geomodeling in order to improve sustainable mining extraction, especially for predicting and avoiding the formation of sinkholes disaster potential zones. Systematic exploration drill holes performed in the Verkhnekamskoye potash deposit (Perm region, Russia) have been used to build a comprehensive 3D model for better understanding the spatial repartition of the ore quality (geometallurgy). A precise modelling of the mineralized layers allows an estimation of the in-situ ore reserves after interpolating by kriging the potassium (K) and magnesium (Mg) contents at the node of a regular centred grid (over a million cells). Total resources in potassium vary according to the cut-off between 4.7Gt @ 16.1 % K2O; 0.32 % MgCl2 for a cut-off grade at 13.1% K2O and 2.06 Gt @ 18.2 % K2O; 0.32 % MgCl2 at a cut-off of 16.5% K2O. Most of reserves are located in the KPI, KPII and KPIII layers, the KPI being the richest, and KPIII the largest in terms of tonnage. A systematic study of the curvature calculated along the roof of the mineralized layers points out the location of potential main faults which play a major role in the formation of sinkhole during exploitation. A risk map is then derived from this attribute.

DEEP COPPER AND SILVER DEPOSITS – A CHANCE FOR POLISH METAL MINING INDUSTRY

The deep copper-silver ores in the central and eastern parts of the Fore-Sudetic Monocline had been unknown until the mid-1950s. During the following decades, gradually progressing studies and analyses of core material from a limited number of deep boreholes drilled in this region made it possible to acquire detailed information and to demarcate areas of potential mineral deposits, along with the estimation of their predicted resources. In spite of the above, due to the technological barriers which limited their profitable extraction to depths not exceeding 1250 m, those areas were not formerly considered as potential mining targets. It is only because of the progressing technological advancement that the extraction of those minerals has currently become possible and attainable, as evidenced by experience from all over the world. Because of the extensive exploration program conducted for several years in south-western Poland by companies belonging to the Miedzi Copper Group, the documenting of deep copper and silver deposits in this area has now become realistic. A primary condition of economically justified extraction is focusing on regions characterised by a higher quality of ore.

Risk-resilient mine production schedules with favourable product quality for rare earth element projects

By estimating ore quality and assuming the distribution of rare earth elements present in a deposit using the total rare earth oxide grade, a mine planner does not have the necessary resolution to assess the geological risk and inform their decisions. Thus, it is unlikely that the mine production schedule will maximise the generation of cash flows or meet the expected production targets. Suitable representation of a deposits’ spatial variability and uncertain characteristics, coupled with advancements in the field of stochastic mine planning, can offer the tools to develop a mine design that will yield a higher net present value and ensure more reliable ore quality. The application herein consists of the joint simulation of 15 rare earth elements in a monazite–bastnäsite deposit and the generation of a risk-resilient production schedule that maximises net present value and ensures consistent ore grades and rare earth mineral blends at the processing facility.

The role of the thermal convection of fluids in the formation of unconformity-type uranium deposits: the Athabasca Basin, Canada

In the global production of uranium, ~18% belong to the unconformity-type Canadian deposits localized in the Athabasca Basin. These deposits, which are unique in terms of their ore quality, were primarily studied by Canadian and French scientists. They have elaborated the diagenetic–hydrothermal hypothesis of ore formation, which suggests that (1) the deposits were formed within a sedimentary basin near an unconformity surface dividing the folded Archean–Proterozoic metamorphic basement and a gently dipping sedimentary cover, which is not affected by metamorphism; (2) the spatial accommodation of the deposits is controlled by the rejuvenated faults in the basement at their exit into the overlying sedimentary sequence; the ore bodies are localized above and below the unconformity surface; (3) the occurrence of graphite-bearing rocks is an important factor in controlling the local structural mineralization; (4) the ore bodies are the products of uranium precipitation on a reducing barrier. The mechanism that drives the circulation of ore-forming hydrothermal solutions has remained one of the main unclear questions in the general genetic concept. The ore was deposited above the surface of the unconformity due to the upflow discharge of the solution from the fault zones into the overlying conglomerate and sandstone. The ore formation below this surface is a result of the downflow migration of the solutions along the fault zones from sandstone into the basement rocks. A thermal convective system with the conjugated convection cells in the basement and sedimentary fill of the basin may be a possible explanation of why the hydrotherms circulate in the opposite directions. The results of our computations in the model setting of the free thermal convection of fluids are consistent with the conceptual reasoning about the conditions of the formation of unique uranium deposits in the Athabasca Basin. The calculated rates of the focused solution circulation through the fault zones in the upflow and downflow branches of a convection cell allow us to evaluate the time of ore formation up to the first hundreds of thousands years.

MANAGEMENT OF PROCESSES FOR ENRICHMENT OF COPPERMOLYBDENUM ORES USING QUALITY CONTROL QUALITY

In the process of ore beneficiation, applying open control loop systems using ore quality as input parameter, proves very effective. To determine the ore quality, on-line analysis of its material and mineralogical composition, impregnation of valuable components is carried out. Based on the analysis results, ore streams are formed at the processing plant, and effective processing conditions are selected. Modern systems of visual metering analysis of ore create the basis for efficient automated control of beneficiation processes, based on the principle of advanced control of ore grade. To improve the accuracy of determining the ore mineral composition, a special installation has been developed, which provides cleaning of ore from slurry. The installation enables achieving high accuracy of the ore mineralogical composition analysis. Tests of the ore grade visual metering analysis system, carried out using copper-molybdenum ores of the Erdenet GOK, have shown high reliability and efficiency of the system.

Состояние хромовой промышленности России

The paper analyzes the state of the sources of raw materials and production of chrome alloys in the Russian Federation. It is mentioned that the increase of chrome ore reserves in the last decade is insufficient, and principal reserves are located in the regions hard to develop. Issues of the production of charge chrome, changing standards towards decrease of chromium in the ferrochrome, and implementation of direct current furnaces for processing poor ores, dressing rejects and industrial wastes are becoming important because of low ore quality in the deposits currently being mined. Unlike the production of other ferroalloys where the tendency to development of small specialized plants is observed, production of ferrochrome is characterized by consolidation and establishment of holdings that incorporate not only mining and processing, but also preparative industries like sintering plants as well as mining and preparation of non-ore materials, viz. limestone and quartzite.

Optimisation of the blast furnace burden based on its primary slag formation behaviour

The iron ore consumption doubled several times due to the rapid development of ironmaking industry in China, resulting in the worse quality of iron ores in the past decade. Therefore, the efficient utilisation of poor quality iron ore resources is of great importance for the sustainable development of ironmaking industry. In this work, a new method for optimisation of blast furnace burdens was studied based on the primary slag formation behaviour because it has significant influence on the formation of the cohesive zone. The results showed that there was obvious interaction between sinter and acid iron ores at high temperature, and the primary slag formation behaviour was clearly improved by the high temperature interaction. The poor quality lump ore could be utilised together with high basicity sinter and self-fluxed pellet to enhance the high temperature interaction. Besides, increasing CaO and MgO content in blast furnace burdens would further improve their primary slag formation behaviour and the performance of cohesive zone.

Simulation of weathered profiles coupled with multivariate block-support simulation of the Puma nickel laterite deposit, Brazil

Modelling and assessing spatial variability and uncertainty of mineral deposits is critical for both capital investments in mining projects as well as operational issues once a mine is developed. However, traditional approaches for modelling geological domains and geostatistical estimation provide smoothed representations of the pertinent deposit attributes, ignore spatial variability and, thereby, can mislead downstream decisions. Spatial variability and related uncertainty in modelling mineral deposit characteristics of interest, ranging from metal content and geological boundaries to geomechanical - geotechnical rock properties, can be modelled and quantified by stochastic spatial simulations. This is demonstrated through a detailed, step- by-step application to the Puma deposit, a major nickel lateritic asset in Brazil, part of the Onça-Puma mining complex. To integrate the variability of the regolith profiles of the deposit, their thicknesses are calculated after an unwrinkling process is applied and the deposit is then jointly simulated using min/max autocorrelation factors (MAF). The realizations serve as geological boundaries within which Ni, Co, Fe, SiO2, MgO and Dry-tonnage factor (DTF) are subsequently jointly simulated directly at block support scale. The final result is a series of equally probable representations of the Puma deposit, which are used to quantify and assess the uncertainty about key aspects of the project at the Puma deposit, such as the uncertainty of the in-situ resources documented herein, and the strict control of the ore's quality that feeds the ferronickel processing plant. The framework presented shows the advantages of the MAF and direct block simulation approaches for the efficient joint simulation of spatially variant geological attributes of large deposits for industrial environments. The methods presented are general, new in the context of geotechnical and geomechanical engineering, and can assist in the modelling of spatial variability and quantification of uncertainty linked to geotechnical rock properties and pertinent lithological boundaries.

Impact of salinity on warm water‐based mineable oil sands processing

AbstractContinuous use of caustics and increased level of water recycling inevitably increase the salinity of process water, which is a growing challenge in the current warm water‐based bitumen extraction process. The current study aims at understanding how salinity of process water affects bitumen recovery from mineable oil sands ores. Laboratory flotation results showed an ore‐dependent effect of salinity on bitumen recovery and froth quality. Processing of low‐grade ores suffered a dramatic loss in bitumen recovery with increasing NaCl up to 4000 ppm (i.e. 1574 ppm Na+) at pH 8.5, while only a marginal effect of salinity was found on the processability of a high‐grade ore. The use of caustics as a conventional approach to increase bitumen recovery and froth quality of poor processing ores showed a more severe negative impact of salinity on the processability of low‐grade ores. Salt addition was found to be detrimental to bitumen liberation and bitumen‐bubble attachment in the presence of fines, more so at higher pH of processing water. Increasing salt concentration in solution led to a significant decrease in the magnitude of negative zeta potentials for both bitumen and fine solids. These findings provide scientific guidance to searching for remediation strategies other than using caustics. Such an approach studied was the blending of low‐grade ores with high‐grade ores to minimize the negative impact of increased salinity in recycle water on bitumen extraction.

Automated Quantitative Rare Earth Elements Mineralogy by Scanning Electron Microscopy

AbstractIncreasing industrial demand of rare earth elements (REEs) stems from the central role they play for advanced technologies and the accelerating move away from carbon-based fuels. However, REE production is often hampered by the chemical, mineralogical as well as textural complexity of the ores with a need for better understanding of their salient properties. This is not only essential for in-depth genetic interpretations but also for a robust assessment of ore quality and economic viability. The design of energy and cost-efficient processing of REE ores depends heavily on information about REE element deportment that can be made available employing automated quantitative process mineralogy.Quantitative mineralogy assigns numeric values to compositional and textural properties of mineral matter. Scanning electron microscopy (SEM) combined with a suitable software package for acquisition of backscatter electron and X-ray signals, phase assignment and image analysis is one of the most efficient tools for quantitative mineralogy. The four different SEM-based automated quantitative mineralogy systems, i.e. FEI QEMSCAN and MLA, Tescan TIMA and Zeiss Mineralogic Mining, which are commercially available, are briefly characterized.Using examples of quantitative REE mineralogy, this chapter illustrates capabilities and limitations of automated SEM-based systems. Chemical variability of REE minerals and analytical uncertainty can reduce performance of phase assignment. This is shown for the REE phases parisite and synchysite. In another example from a monazite REE deposit, the quantitative mineralogical parameters surface roughness and mineral association derived from image analysis are applied for automated discrimination of apatite formed in a breakdown reaction of monazite and apatite formed by metamorphism prior to monazite breakdown.SEM-based automated mineralogy fulfils all requirements for characterization of complex unconventional REE ores that will become increasingly important for supply of REEs in the future.

Prediction of Iron Ore Sinter Properties Using Statistical Technique

Due to the drastic change in iron ore qualities, maintaining consistency in sinter property has become a challenge for steel manufacturing industries, resulting the irregularities and disturbances in the blast furnace iron making. The present work aimed to develop a prediction model for physical, mechanical and high temperature properties of iron ore sinter well in advance from the plant process parameters to support smooth functioning of the furnace. Correlation matrix, multiple linear regression and artificial neural network (ANN) analysis were performed for the development of the model. This predictive system for three important sinter properties [Mean particle size (MPS), tumbler index (TI) and reduction degradation index (RDI)] was established based on back propagation (BP) neural network, which was trained and tested by actual plant data. The prediction accuracy of MPS, TI and RDI using that ANN model is 79, 91 and 76 %, respectively. A user-friendly graphical user interface has been developed using C language based on the model. The application results showed that the prediction system had high accuracy rate, stability and reliability.

Evolution of flotation chemistry and chemicals: A century of innovations and the lingering challenges

The history of mineral flotation is a record of over a century of impressive innovations, especially in the development of flotation chemistry and chemicals, the principles of their action, their manufacture and the role they play in sustaining efficiencies and productivities even as the quality and grade of ores decline, and the severity of the challenges increases. We emphasize the major innovations that have directed progress on this subject, especially those innovations that have positively impacted industrial scale applications. An analysis is given that organizes the evolution of flotation chemistry and reagents into four historical and one emerging period. As in many other technology areas, flotation chemistry research and development have reached a plateau in the face of mounting industry challenges related to water and energy consumption, decline in the ore quality, economic uncertainty, and health, safety and environmental (HSE) aspects. Elevating us off this plateau will require several necessary steps, including more detailed, holistic understanding of practical systems, better integration of chemical effects into flotation models, a more robust education system to produce adequate numbers of qualified engineers, development of novel technologies and chemical schemes that address the challenges identified above, and a stronger commitment by mining companies to actually adopt those innovations. Success in developing novel technologies will be greatly improved when we can confront the chemical complexity in flotation systems. This in itself is one of the grand challenges in the emerging period. We outline some directions to achieve this goal. The mineral processing industry must take the initiative towards these goals in order to bring about the necessary transformation if we are to maintain a sustainable technology.

Optimization of iron ore sintering process based on ELM model and multi-criteria evaluation

Optimization of iron ore sintering process is to maximize the productivity and the sinter ore quality while minimizing the energy consumption. However, these economic and technical criteria are sometimes contradictory and the improvement of one criterion generally leads to the deterioration of other criteria. This paper aims to seek the optimal manipulated parameters from the production data by considering this contraction. Several typical groups of manipulated parameters were firstly obtained by clustering the production data, and then one new artificial neural network model--online sequential extreme learning machine (OS-ELM) was established to predict FeO content and tumble strength of sinter ores for each group. Validation results showed that the OS-ELM model established possessed a higher accuracy than conventional BP (back propagation) model. Finally, a multi-criteria evaluation method--VIKOR was applied to obtain a set of compromise optimal solutions. Taking into account both economic and technical criteria, the final solutions acquired are instructive, and the optimal solution can directly reduce fuel consumption by about 0.5 kg per ton sinter ore without degrading sinter ore quality seriously.

Improving the intelligent methods of management of processes of enrichment on the basis of visiometrics analysis of the grade of the ore

For the flotation process is effective using of open control loops, which are used as input parameter the ore quality. To determine the quality of ore is carried out on-line analysis of its elemental and mineral composition and structure. The basis of the operational analysis is the measurement of X-ray and visible light. To improve the accuracy of determining ore mineralogical composition, new techniques and facilities have been developed. At the conveyor ore analysis, special lighting systems were tested, using alternating focused and flat light fluxes. Such systems provide highly accurate in-stream measurements of ore properties. A special flatbed facility for optical spectrumbased estimation of fine-crushed ore has been developed, being incorporated into the existing system of ore sampling and analysis. Application of the flatbed facility renders possible a high accuracy of determining ore mineralogical composition. Modern systems for optical spectrum-based estimation of ore grade provide a basis for effective automated control of ore beneficiation processes, based on the principle of advanced ore grade control. The systems implemented at the Erdenet processing plant (Mongolia) contributed to increasing copper and molybdenum recovery.