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By P J. Handley

"Predicting how coal seams will be beneficiated through the coal handling processing plant (CHPP) has long been challenging within BHP Coal. Various coal seams from different areas are mined and stockpiled separately, often depending upon a deleterious coal quality parameter; high/low trace elements for example. These stockpiles are then fed in different ratios into the CHPP to produce the desired product/s. In understanding the washability characteristics of the feed source, mine geologists and process engineers work together to improve the beneficiation of different coal materials through the CHPP.For the majority of the BHP Coal deposits, the washability data is available for the coal seams across the deposits. However, no previous standardised modelling and prediction technique existed that could ensure the correct information was available for forecasting and refining CHPP processes. This paper will discuss the steps undertaken to implement a geometallurgical prediction tool that simplified and streamlined the washability modelling and yield estimation process. The value realised to the BHP Coal assets resulting from this process was: improved compliance to plan increased throughput increased CHPP recovery through improved efficiencies and increased revenues.CITATION:Handley, P J, 2017. Washability modelling and estimation techniques used to improve coal handling preparation plant beneficiation, in Proceedings Tenth International Mining Geology Conference 2017, pp 327–336 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Sep 20, 2017

By Chris M. Healey

"Abstract - Perhaps the single most significant variable in the evaluation of a mining project is the reserve estimate. Many parameters are considered when estimating reserves, among them geology. This paper examines the link between the quality of a reserve estimate and a good understanding of the geological controls for the deposit. A clear understanding of the geometry is essential to the accurate definition of the shape and size of the deposit. This includes the definition of any structural controls as well as the proper interpretation of the stratigraphy. Further when the distribution of grades is erratic and there is consequently a high nugget effect, there are significant problems in estimating the true grade of the deposit.Two Saskatchewan examples are presented, one with good knowledge of the controls and therefore good estimates of reserves, and the other with a poor understanding of the geology and resultant problems in deriving good estimates. In both cases the reserve estimates at various stages in the project development are compared to actual results from underground work. The first example is the Star Lake Mine where just about all the estimates were within 10% of the actual on both tonnage and grade. The Laurel Lake deposit is discussed to show how problems in interpreting the geological data make reserve estimation very difficult. Laurel Lake has the additional problem of erratic grade distribution."

Jan 1, 1992

By H. W. Wevers

Fatigue failure and accompanying brittle failure occurs frequently in heavy mining equipment. This paper discusses how fracture mechanics can be applied as a tool for crack control and crack management. Information is provided to determine if particular components are prone to brittle failure. By using existing fracture mechanics formulae, an estimation of the critical crack size can then be made. It is explained that for a successful application of fracture mechanics, both the actual engineering stress in the component and the mechanical properties of the applied material must be known. The importance of toughness at low temperatures is quantitatively illustrated by calculating critical crack sizes at room temperature and at below-zero temperatures. Understanding the possibilities of fracture mechanics will also produce a climate in which the purchaser of equipment can more precisely analyze the relative quality of components with respect to crack tolerance and failure prevention. In this manner, communication between the user and manufacturer of equipment may also become more precise and effective, leading to improved design.

Jan 1, 1977

By Waldbillig. D.

A baseline of the poisoning effect of hydrogen sulfide (H2S) fuel impurities on solid oxide fuel cell (SOFC) anodes was developed using polarization testing. After the baseline behaviour was characterized, tests to study the effect of various H2S concentrations on the rate and amount of cell voltage degradation and recovery were performed. Attempts were made to improve the rate and amount of recovery by various methods. Testing was very reproducible, but significant electrochemical performance degradation was seen after all H2S poisoning tests even at an H2S concentration of 0.1 ppm. Degradation is initially quite rapid, but after a period of time the rate of degradation levels off. After poisoning was complete, the H2S flow was stopped and the cells were allowed to recover. Some recovery was seen after poisoning, but cell performance was never fully recovered.

Jan 1, 2005

By D. M. Hausen

A computer program has been developed by Newmont Exploration to convert mineralogic data by XRD into rock type and ore type classifications. This method has proven useful in identifying lithology from cuttings samples, where percussion drilling was an alternative to expensive core drilling. Computer printouts of rock type and ore type identifications can be generated simultaneously with mineralogic analyses, resulting in a considerable time savings in manual calculation. XRD-computer logging was first applied to the Carlin mine in north central Nevada, and later to the Maggie Creek and Gold Quarry gold deposits, southeast of the Carlin mine. Impure Paleozoic limestones of the "lower plate" Roberts Mountain Formation and the "upper plate" transitional facies have been decarbonatized to altered siltstones and shaley units along vertical faults and permeable stratiform horizons. Advanced stages of decarbonatization were accompanied by silicification. Quantitative XRD data are initially sorted into principal rock type units (limestones, siltstones, dolostones, shales) based on major mineralogic components (calcite, quartz, dolomite, clays). On the basis of relative amounts of less major constituents, descriptive subclassifications (dolomitic limestones, dolomitic siltstones, argillaceous cherts) are made. XRD lithologic data provide assistance in correlating lithologic units, and delineating favorable replacement horizons associated with gold mineralization.

Jan 1, 1982

By Moreno Pescara, Luca Soldo, Piergiorgio Grasso

"Risk management in tunneling is more important today than it was a few years ago, considering increasing demands for safety and environmental and socio-economic sustainability, which are now required by citizens, owners, lenders, and insurers. Moreover, our current risk management philosophy should not only address risk avoidance and mitigation, but should also be used as a means of value creation, benefiting the overall project. Given the strategic implications of risk management, the authors intend to present, in this paper, a comprehensive overview of references and experiences from current practice—e.g., what is missing or weak, as well as possible or necessary developments that can have a key role in implementing effective risk management, particularly for a project’s design and construction phases. Therefore, as God has set some things in broad daylight; as he has given us some certain knowledge, though limited to a few things so, in the greatest part of our concernments, he has afforded us only the twilight, as I may so say, of probability (John Locke) PREFACE Many large-scale engineering and construction projects suffer millions of dollars in cost overruns, delays in design and construction, and operability troubles once finally completed (Edward W. Merrow, 2011). The undesired effects of these problems can become disastrous for large-scale megaprojects (those that typically cost US$1 billion or more), particularly considering that these are increasingly used as the preferred delivery model for infrastructure (Bent Flyvbjerg, 2014), often in public-private partnerships (PPPs). McKinsey G.I. (2015) has estimated that bridges and tunnels average 35% in cost overruns, and roads 20%. Some of the values published by Flyvbjerg (ibidem, 2014) for projects with relevant underground elements are the highest, with cost overruns from 60% to 300%. The analysis of 32 other case histories (from 1994 to 2010) given by Hartmut, R. (2011, IMIA Annual Conference, Amsterdam) indicates an average increase of costs around $55 million, with a 20-month average delay."

Jan 1, 2016

By N. C. Miller

In situ stope leaching is an innovative mining system that reduces the surface impacts of conventional underground mining. As in any leaching operation, stope leaching requires hydrologic site characterization and control of leaching solutions. Several tracer tests, using sodium chloride (NaCl) in various concentrations, were conducted by the U. S. Bureau of Mines (USBM) in an underground experimental stope to simulate a leaching environment. The tests were conducted in fractured crystalline rock that was partially saturated. As tests progressed, the surrounding fractures became more saturated. A predominant flow direction away from the stope was found during testing. Testing procedures, preliminary results, and remediation ideas based on field observations are presented in this paper.

Jan 1, 1995

By Knut L. Sandvik, Erik Larsen

Crystalline silicon solar cells are the most important solar cells manufactured today. This will most probably remain the situation the next decade. The future silicon feedstock is most likely not reject from the production of electronic-grade silicon. There will probably be a more direct solar-grade silicon route, excluding the electronic-grade silicon "detour". Estimated global solar energy demand in 2001 required approximately 5,500 tons of silicon feedstock. This required 65,000 tons of quartz. If the trend continues, the solar energy demand in 2010 would require approximately 30,000 tons of silicon feedstock and 350,000 tons of quartz, although the need for quartz probably will be lower than this. Quartzite has been regarded as the most suitable primary raw material used in the silicon solar cell production chain. This may change as the raw material requirements for the production of metallurgical-grade silicon are most likely to change. In addition, quartz or other silica-containing minerals from other rocks may be of a higher purity or contain lesser amounts of the most harmful elements. This favours increased beneficiation of primary raw materials in the future solar silicon feedstock production chain.

Jan 1, 2003

By S. M. Javad Koleini

Processing of phosphate ore sample was investigated for increasing phosphate content and reduction of its gangue minerals such as carbonates and silicates. Experimental designs were per-formed using Taguchi method. Different flotation methods were investigated for Moundon phosphate ore sample and three methods were used as follow: direct cellophane flotation, reverse calcite flotation and reverse quartz flotation. Because of the sensitivity of cellophane flotation to slime content, prior desliming was carried out before the experiments. Direct flotation experiments carried out and a concentrate contained 23.80% P2O5, 6.88% SiO2 and 72.33% recovery were produced. The achieved P2O5 content in the produced concentrate from reverse flotation of calcite was 26.44% and the recovery was 82.56%. The concentrate products obtained at optimum conditions by direct flotation of phosphate and indirect flotation of calcite were subjected to indirect flotation of calcite and direct flotation of appetite and final concentrates with P2O5 grade of the order of 24.19% and 26.96% were obtained, respectively. It was concluded that one stage direct flotation is unavoidable to achieve a product with low SiO2 content.

Jan 1, 2014

By S. Perez

Core drilling is a fundamental process in the mineral exploration industry. As deep exploration in hard rocks is accelerated due to the depletion of near ground mineral resources, deep-drilling operations need to reduce their reliance in operators experience and begin to implement new technologies in order to increase efficiency and cost-effectiveness of the overall process. Currently, lack of real-time information on the bit/rock interaction is a major problem. Therefore the mechanism behind the acoustic emission, which is a proven technique for remote monitoring, generation in mechanical rock cutting must be understood in order to provide real time information about the rock. This paper aims to identify the influence of mineral composition of granitic rocks on the acoustic emission (AE) during rock abrasivity test with a single contact tool and to evaluate the feasibility of AE as a means to infer Cerchar Abrasivity Index (CAI). Single contact tool will provide precise and accurate description of the source of AE. To provide constant grooving speed Cerchar apparatus was modified to monitor AE during rock/tool interaction. Tests on the modified Cerchar apparatus are carried out under the static load of 70N and cutting speed of 1 mm/s. A Scanning Electron Microscope (SEM) is utilized to visualize the groove in the rock and to identify the mineral composition through Back-Scattered Electrons (BSE) reflected from the rock sample. Based on the microscope images, it was found that biotite shows a larger groove area and plate-like fractures accompanied with burst-type AE signal, whereas plagioclase and quartz, which are characterized by similar hardness and BSE brightness, possess shattered-like fractures and more continuous-type AE signals. In addition, a-value of the Gutenberg-Richter scale has been found to well correlate with Cerchar Abrasivity Index (CAI).

Jan 1, 2015

By Ingvar Ymén, Anders Sandc, Jan Rosenkranzc, Lisa Malma, Ann-Sofi Kindstedt Danielssonb

The understanding of particle surface properties is essential for the study and evaluation of froth flotation phenomena, particularly in the investigation of various chemical or reagent effects. Dynamic Vapor Sorption (DVS) is a method used for the analysis of surface properties of powders for instance in the pharmaceutical industry. To the knowledge of the authors, it has however not been used before in applications related to mineral processing. The DVS technique involves measurement of the water uptake of a relatively small amount of sample as a function of the relative humidity (% RH) in a temperature-controlled environment. The purpose of this work was to evaluate the method and investigate how it can complement existing techniques for surface characterization in mineral processing. Four samples (feed, CuPb concentrate, Cu concentrate and Pb concentrate) from the Cu – Pb flotation process in the Garpenberg concentrator, Sweden, were analyzed by DVS and the traditional capillary absorption technique (Washburn capillary rise). This enabled comparison between the two methods and evaluation of their respective advantages and disadvantages. Both methods give the expected ranking of the hydrophobicity for CuPb concentrate, Cu concentrate and Pb concentrate, but a discrepancy was observed for the feed. Washburn gave a value for the contact angle which was in the same range as for the CuPb concentrate, whereas DVS gave a value for the moisture uptake which was much higher than for the CuPb concentrate. Thus, DVS ranks all samples correctly, but with an unexpectedly high value for the feed whereas Washburn gives good ranking for three samples out of four. Potential reasons for the discrepancies are discussed.

Jan 1, 2018

By Luis R. Bittencourt

Research efforts have been made to characterize a refractory Brazilian bauxite ore composed basically of gibbsite, kaolinite and quartz. Detailed polished-section microprobe analysis of the unbroken ore has been used to describe the liberation characteristics and the association between mineral phases. The linear grade distributions for selected particle size fractions were determined by means? of a particular implementation of King's Random Fracture Model that uses the exponential model for the distribution of linear intercepts through both dispersed (kaolinite) and continuous (gibbsite) phases. The corresponding volumetric grade distributions were then determined by means of a constrained optimization technique for the solution of the transformation equation. Batch flotation experiments were carried out to determine the kinetics for particles of different sizes and the results correlated with the liberation spectrum for each size class.

Jan 1, 1991

By Y K. Ji, B J. Chung

In recent years, the utilisation of ultra-fine ore in ironmaking has gradually increased due to the depletion of high-quality iron ore. The use of ultra-fine ore in the ironmaking process is typically energy intensive and leads to high CO2 emissions. The improvement of sinter reducibility is one of the methods used to reduce the environmental impact of using fine ore.In this study, a high-strength and high-reducibility sinter manufacturing process was investigated by controlling the sintering reaction. The key technology used in this method is the manufacture of mini-pellets by selective granulation equipment. The mini-pellets consist of iron ore, limestone and burnt lime and are designed to melt at temperatures below 1200°C. The molar ratio of CaO to Fe2O3 of the mini-pellets is 0.25~0.75. The 2~5 mm diameter mini-pellets are manufactured with burnt lime as the binding material.During the sintering of mini-pellets, goethite, which has relatively high reducibility, should be retained as residual ore in the sinter cake. The strength of the sinter cake was kept by the bonding reaction of the mini-pellets, which have a low melting temperature. This is the main principle of the reaction-controlled sintering method.The reaction-controlled sintering method manufactures a high-strength and high-reducibility sinter cake and increases sinter productivity by around 15 per cent using ultra-fine iron ore.CITATION:Chung, B J and Ji, Y K, 2015. Production of high-quality sinter by controlling the sintering reaction, in Proceedings Iron Ore 2015, pp 21–28 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By Robert C. Freas

Dravo Lime Company has opened a new 290m (940 ft.) deep lime-stone mine near Maysville, Kentucky. As the mine was opened there were many unknowns as to the stress relationships within the rock, and their influence, if any, on the selected mining method. Therefore, a system of overlay geologic and structural maps, borehold extenso-meter measurements, and oriented photography was developed for the purposes of monitoring the internal structural relationships of the rock mass. This paper presents a description of the methods used, the observations made, and the conclusions and recommendations made as a result of the initial monitoring program.

Jan 1, 1977

By M. Saghaeian, R. Hejazi, M. Mohammadinejad, M. Zare

"Water quality and quantity at the Tailing Thickening Section of processing plants is considered to be a crucial factor and impacts the performance of several sections. Therefore, gaining stable and effective performance at the Tailing Thickener Section is one of the principal goals of minerals processing plants. Different factors such as: qualitative and quantitative sustainability of plant feed, the balance between the mass of input and output water flow, the dissolving method and distribution of flocculant and the amount of dirt, solid percent of thickener inlet pulp, affect the performance of Tailing Thickener. The present study investigates the successful improvement of Tailing Thickener performance at Jalal Abad Hematite Iron Ore Concentrate plant through optimizing the above operational parameters. For this purpose, the following optimizations have been done: homogeneity and sustainability of plant input feed rates, fine pulp removal collected by the bag filters at the input of the thickener, adding an quietness box before moving the tail pulp into the thickener to reduce the pulp turbulence, replacing flocculant pump and injection pipes, improving water mass balance which leads to optimizing and stabilizing the concentration of input tail pulp into the thickener, adding a mixer to increase the flocculant preparation time, increasing the locations for adding flocculant to thickener from 1 point to 6 points. Applying the above modifications and monitoring the Tailing Thickener performance over the course of months, has led to the improvement of recovered water quality from 500 ppm to 200 ppm, increasing the solid underflow of the thickener from 40% to 48.5%, and similarly, reducing water loss by 60%. Of other important effects, due to improvement of water quality, grade of final concentrate 0.5% increased and because of 73% increase in monthly working hour, concentrate tonnage 55% increased. Finally, sludge thickener optimization has had a significant effect in selecting and designing the dewatering system from the underflow of the sludge thickener."

Jan 1, 2018

By Adolph V. Mitterer

International Minerals and Chemical Corporation operates one of six potash mines in the Carlsbad potash basin. More than 90 percent of America's potash is produced at Carlsbad and IMC accounts for about one-fifth of that amount, Since the Company began operations in 1941 it has mined nearly 50 million tons of ore. Of the two types of ore mined at Carlsbad the principal tonnage is sylvinite in which sylvite-potassium chloride-is the ore mineral. It is produced by IMC as well as by all other mines in the area, In addition to sylvinite IMC is the exclusive producer of langbeinite ore--potassium-magnesium sulfate. From its two ores, International produces a spectrum of 8 high-quality agricultural and industrial chemical products.

Jan 1, 1959

By J. A. Madonna

Independent prospectors and small to large-scale exploration company personnel have requested, and are in need of, guidance in geochemical field sample collection methods which will provide the most reliable results during chemical analysis. In cooperation with analytical laboratories, experienced geochemical exploration scientists and mining companies a systematic collection procedure has been developed. The procedure consists of collecting uncontaminated, water, sediment and rock chip samples of the appropriate quantity and/or dimensions to meet the needs of analysis.

Jan 1, 1999

By V Malysiak, N J. Shackleton

In the flotation of platinum group minerals pyroxene is a major gangue mineral. This study shows using zeta potential and ToF-SIMS analyses that when pyroxene is exposed to copper, nickel and/or calcium ions in solution at alkaline pHs a surface reaction occurs between the hydroxy species, in the case of copper and nickel, or divalent calcium ions and the pyroxene surface which influences the floatability of the pyroxene. Following exposure to copper and nickel ions at pH 9 addition of SIBX resulted in the pyroxene floating readily. It is also shown, in the case of copper, that the activating effect of the adsorbed copper hydroxy species can be reduced by the addition of complexing amines prior to SIBX. Proposals are made to explain these observations.

Jan 1, 2005

By C. Alexandru Sonoc

Donnan Dialysis uses ion exchange membranes to extract and separate cations. The driving force is provided by differences in chemical potential, rather than by electric fields or pressure. A Donnan Dialysis based process to recover lithium, nickel, cobalt, manganese, and organic acid lixiviant from recycled lithium ion battery cathodes is under development. In this paper we present a model of Donnan Dialysis and results of simulations of the aforementioned process. The simulations show that 170 m2 of membranes can process 1000 L of leachate ([Li+] = 0.285 M, [Co2+] = [Ni2+] = [Mn2+] = 0.095 M, pH 2) in two days and recover 94.1% of the lithium (as lithium carbonate), 99.4% of the transition metals (as mixed sulphates ready for solvent extraction), and all of the organic acid using 423 mol of H2SO4 and 268 mol of KHCO3.

By Jan Kvinge, Aina Opsal Bakke, Yanjun Li, Jan-Ove Løland, Svein Jørgensen

"Compound casting is a very attractive approach to reduce the weight of components for some specific applications while keep both the functional and the mechanical property requirements. In this work, Al-7Si-Mg alloy /copper compound castings were produced through a low pressure die casting process. To reduce the oxide present in the interface, flux coating of the copper pipes was tested. The interface layer formed between the two alloys was investigated using Optical Microscopy (OM), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS). Vickers Micro-hardness was also measured across the interface. Results showed that the flux coating prevented the formation of the metallic bond between copper and aluminum. Instead, high concentrations of potassium, magnesium and fluoride, coinciding with formation of KMgF3 and MgF2, were detected in the interface. In the castings without surface treatment, a continuous metallurgical bond was achieved. In the bond layer, various Al-Cu intermetallic phases have been detected. In addition, formation of primary silicon particles in the reaction layer was observed in all castings. The mechanism for the formation of the intermetallic phases and the strength of the interface layer have been discussed.INTRODUCTION Recent development in the automotive industry has focused on producing lightweight components, which can reduce CO2 emission and increase the efficiency. Often, one material alone is not able to meet the requirements for a specific use. The need for lightweight bimetallic components has therefore increased. Aluminum-copper bimetallic components can be used in wires and bus bars where conductivity is an important factor (Lee, Bang, & Jung, 2005). Compared to Al-Cu alloys, Al-Cu bimetallic components can reduce both weight and cost without reducing electrical and thermal conductivity (Sheng, Yang, Xi, Lai, & Ye, 2011). A challenge is, however, that aluminum and copper have high affinity to each other, especially at elevated temperatures. This causes formation of brittle intermetallic phases with high electric resistance (Liu, Wang, Sui, Wang, & Wenjiang, 2016). In addition, both metals are subjected to oxide formation on the surface. Copper is especially exposed to oxidation at elevated temperatures (Pinnel, Tompkins, & Heath, 1979), while a thermodynamically stable oxide layer will spontaneously form on the aluminum surface (Papis, Loeffler, & Uggowitzer, 2009). Oxides are known to be passive substrates, which will reduce wettability and will thus prevent the formation of metallic bonding between aluminum and copper (Papis, Hallstedt, Löffler, & Uggowitzer, 2008)."

Jan 1, 2018