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By Shuchen Sun, Ganfeng Tu, Chuan Liu, Xiaoping Zhu

The hydrometallurgical residue generated during the hydrometallurgical processing of waste automotive catalysts is valuable as a secondary resource. In this study, a process of platinum recovery from the hydrometallurgical residue by high-temperature smelting process was proposed. Results of lab- and pilot-scale experiments show a high recovery of more than 98% of platinum and glass slag was successfully obtained by controlling the Fe3O4 addition, C/Fe3O4 mass ratio, CaO/SiO2 mass ratio, smelting temperature, and holding time at 15 wt%, 0.4, 0.6, 1500 °C, and 120 or 60 min, respectively. Results from the pilot-scale show that the platinum contents in the glass slag and alloys were less than 4 g/t and more than 0.6 wt%, respectively. Therefore, the process proposed in this study is a prospective and effective approach for reutilization of hydrometallurgical residue containing platinum.

Oct 12, 2020

By J. S. Carman

As with the slogans of Madison Avenue, catch words or phrases frequently become topical. Much is heard these days of the confrontation between governments of developing countries and international mining capital. In actual fact, sadly there are too few cases of anything as positive as confrontation because such an action at least signifies a dialogue which may begin badly but end up fruitfully. Instead we have in general a climate of indifference and fear with the mining companies of note marking off most of the developing world as being unsafe for investment. There is an unreal air to this damaging impasse. The common sense and objectivity which are prerequisites of positive action are lost in a swirling cloud of mythology, embraced largely by governments. Let us examine some of the dangerous misconceptions.

Jan 1, 1977

By J. A. Marts, R. C. Gilmore, Jr. Bogin, S. Saki, J. F. Brune, J. W. Grubb

"Researchers at the Colorado School of Mines have studied the influence of headgate side ventilation controls near the longwall start-up room on the formation of explosive gas zones (EGZs) in underground coal longwall bleeder ventilated gobs. In a project funded by the National Institute for Occupational Safety and Health (NIOSH) researchers developed a Computational Fluid Dynamics (CFD) model to study the formation of methane-air mixtures in the gob, start-up room, and bleeder entries. The relative change in size and location of EGZs are examined in response to ventilation controls in the headgate side bleeder entries near the start-up room. Modeling suggests that adjustments to the ventilation controls can be made to minimize the size of the EGZ. However the EGZ may form in or around active working areas regardless of the ventilation control settings. Research found regulators on the crosscuts into start-up room and first entry inby can force air into to crosscuts outby the start-up room causing more air to flow through the gob. INTRODUCTION Underground longwall mine ventilation systems may operate with either a bleeder ventilated gob or a progressively sealed gob. Bleeder ventilated gobs must meet the standards for safe operation of the bleeder system by examining bleeder system effectiveness. As defined in the United States Mine Safety and Health Administration (MSHA) Program Policy Letter (PPL) No. P13-V-12 (MSHA 2013), the pillared area or gob is “any area where a reduction in pillar size has occurred during retreat mining” and includes the “caved and broken material, the interstices within the caved material, and the open spaces surrounding the caved material.” The PPL further states that the intended purpose of ventilating the gob is “to protect active workings from the hazards of methane accumulations …” The requirements for operating a bleeder system as stated in The United States Code of Federal Regulations (CFR 2013) Title 30 §75.334(b) is to pass ventilation air though the gob “and to continuously dilute and move methane-air mixtures [from the gob] away from active workings and into a return air course …” where the concentration cannot exceed 2 percent methane (CFR 30 § 75.323). Further clarification of the bleeder system as described in the PPL states the following: “A bleeder system includes the area from which pillars are wholly or partially recovered, bleeder entries, bleeder connectors, and all associated ventilation control devices that control the air movement through the area. Bleeder entries are air courses designed and maintained as part of the bleeder system.”"

Jan 1, 2015

By M. Scaggs, L. R. Mendoza

"On January 9, 2014, a large chemical spill occurred on the bank of the Elk River near Charleston, WV. Within hours, the potable water supply for more than 300,000 people was contaminated, and the incident captured national headlines for weeks. Although the primary chemical, crude 4-methylcyclohexanemethanol, or MCHM, is deemed nonhazardous, the impacts of the spill are significant – with all stakeholders, including the public, members of industry, and relevant government agencies experiencing losses. This case highlights the need for a more proactive approach to environmental management, shifting from crisis control and remediation to crisis prevention and risk management. INTRODUCTION On the morning of January 9, 2014, approximately 10,000 gallons of crude 4-methylcyclohexanemethanol (MCHM) leaked from a 48,000-gallon storage tank sitting on the bank of the Elk River near Charleston, West Virginia (WVDEP, 2014; CSB, 2014). MCHM is a chemical commonly used in preparation of fine coal, and is deemed nonhazardous in terms of transportation and storage regulations and also toxicity (CDC, 2014a). Freedom Industries, Inc., a producer and vendor of specialty chemical products, had acquired the storage facility where the spill occurred from Etowah River Terminal, LLC just a few weeks prior in December 2013 (WVDEP, 2014; Freedom, 2005). The direct cause of the spill was ultimately determined to be two small holes in the base of the 76-year-old tank, which were created due to corrosion damage (Bauerlein & McWhirter, 2014). The spill site was located just over a mile upstream from the intake of a municipal water treatment facility operated by West Virginia American Water (WVAW), which serves a population of 300,000 across nine counties in central West Virginia (CDC, 2014a). In a matter of hours, the leaked MCHM made its way through the treatment facility and into the water of nearby homes and businesses, where its strong smell was noticed almost immediately. On the evening of the spill, WVAW concluded that its conventional treatment processes, which include carbon filters to remove a variety of contaminants from water, were not capable of fully removing the MCHM and a “Do Not Use” order was issued for all customers (WVAW, 2014a). With little information readily available regarding the potential human health effects of MCHM, the US Centers for Disease Control and Prevention (CDC) quickly issued an advisory ruling that set a maximum screening level of 1 ppm for safe drinking water (CDC, 2014a). Based on this recommendation, the “Do Not Use” order remained in effect for a total of eight days, until January 17, when the WVAW distribution water was confirmed to have MCHM concentrations below this level (WVAW, 2014a). However, due to the pungent odor of the chemical, its presence was still recognizable in the WVAW facility and in consumers’ tap water after the order was lifted (Manuel, 2014). Recent studies have shown that the chemical can be detected in water at concentrations as low as 0.55 ppb by individuals experienced in odor identification (Rosen et al., 2014); and even individuals with no such training can detect pure MCHM at just 7 ppb (WVTAP, 2014). The fact that this chemical can be sensed at such low levels – indeed far below those considered safe – undoubtedly added to growing public concern. In response to numerous complaints and demands, WVAW continued flushing the treatment facility and pipes until February 25 when MCHM levels were measured below 2 ppb (WVAWb, 2014), and eventually replaced the affected filter media (WVAWc, 2014)."

Jan 1, 2015

By Cengiz Karagüzel, Ömer Canıeren

The mobility of gold and silver metals from refractory ores is very low due to free metal ions in their bodies that bind the transportable and free metal molecules or they are encapsulated in minerals such as sulfides, arsenosulfides, carbonaceous, and clayey materials which make it difficult to extract them. As known from the literature, the enrichment of oxide refractory gold, silver ores, Ag, and Au-rich flotation concentrated from sulfur refractory ores can be leached in the chloride-hypochlorite solutions. In this work, the leaching approach was studied to extract silver ions from refractory ores in the presence of hypochlorite media under high pressure. The mineralogical and scanning electron microscopy analysis of the sample indicated that the silver was encapsulated in barite and quartz minerals in fine sizes. In order to obtain the optimum leaching conditions for the silver ore, the effects of several parameters, namely, temperature, leaching time, NaCl and NaOCl concentration, solid ratio, and particle size on the leaching recovery were investigated in detail. The leaching experiments showed that the highest silver recovery of 62.35% was obtained under the following conditions: temperature of 150 °C, oxygen pressure of 1800 kPa, leaching time of 2 h, concentrations of 2 mol/dm3 and 0.4 mol/dm3 for NaCl and NaOCl, respectively, the solid ratio of 30%, and particle size (d80) 15 μm. The results obtained from this study indicated that the enrichment of refractory silver ores to extract the silver encapsulated in barite and quartz minerals could be possible in the chlorite-hypochlorite under high pressure, a relatively shorter leaching time compared to conventional cyanide leaching.

Jan 28, 2021

By Manuel Gomez

This report presents prediction equations for eleven factors indicative of metallurgical coal quality which have been developed from data obtainable during exploration. Five coke strength parameters and six carbonization product yields have been predicted for coking coals having volatile matter contents in the range 16.3 to 42.1 percent, dry basis. The prediction models developed contain information from the proximate and ultimate analyses, the size consist, and the petrographic composition of coking coals carbonized in BM-AGA retorts at 800°, 900°, and 1,000°C. The equations reported have been evaluated with independent data derived from the 900°C carbonization of 33 binary blends. Present results show that metallurgical coal quality can be predicted ahead of mining. Capability to forecast coal quality is useful in mine planning and should provide basic information for optimization of blending and crushing techniques, leading to the production of uniform coke.

Jan 1, 1968

Invensys’ recently introduced Field Device Manager for Foxboro I/A Series distributed control systems provides the industry’s first solution that takes advantage of both the latest Enhanced Electronic Device Description Language (Enhanced EDDL) and FDT technologies. This combination provides comprehensive lifecycle support to configure, calibrate, commission, diagnose and optimize the performance of any vendors’ foundation fieldbus device. The I/A Series Field Device Manager enables users to take advantage of any EDDL, Enhanced EDDL and/or FDT host deliverables supplied by the device vendor.

Jan 1, 2007

By D. H. Horswill

Red Dog, the world’s largest zinc mine, is located ninety miles north of the Arctic Circle in northwest Alaska on lands owned by the Inupiat Eskimo organization called NANA. NANA received a subsurface title over this resource as part of their settlement lands under the Alaska Native Claims Settlement Act and subsequently entered into a Lease Agreement with Cominco in 1982. Cominco, an international mining company focused on zinc, built and operated the mine. NANA’s principle objective in the development of the mine was to have it contribute to the development of sustainable communities within their traditional region. This meant creating job opportunities in a modern economy while preserving the traditional subsistence lifestyles. Preservation of their culture, language, and traditions are as important to the NANA people today as they were through ages past. The principles of sustainable development – matching economic, environmental, and social goals through continuous communications and high commitment to efficient and effective operations – have been core values for the Red Dog Mine from the beginning. This paper will describe how a large mining operation in a remote corner of the world has been able to contribute toward sustainable development in that region.

Jan 1, 2000

By D. S. Dinsmoor

Boron, estimated to comprise about 0.001 percent of the earth's crust (Fleischer 10), as an element is never found free in nature, although its compounds are found in many localities. the borates are the most important. Sassolite (B(OH)3) and boracite (Mg6C12B1406), non-borates, are-of-minor importance. The crystal structures of most natural borates are still unknown. A classification based solely on the ratio of boron to the total number of cations has been devised (Palache 28). This classification divides the borates into four, sub-groups; anhydrous borates, hydrated borates, borates containing hydroxyl or halogen and compound borates. Only four or five minerals of the hydrated borates group have ever been used commercially. In more recent years, the sodium borates have comprised all but a 'small fraction of all borates used. Borax, the hydrated borate compound, is the most important of all boron compounds. It has been used so long and so often that the layman often confuses borax and boron and, applies the terms synonymously.

Jan 1, 1958

By G. Zhu

Bulk and differential laboratory flotation tests have been carried out using a synthetic mixture of chalcopyrite and molybdenum ore. In addition to boiling and roasting, six different depressants are tested so that the best conditions of separation can be identified. These reagents include sodium cyanide with and without zinc sulfate, potassium ferrocyanide, sodium hydrosulfide, arsenic Noke's reagent, and sodium sulfide. The data indicate that most of these reagents are effective chalcopyrite depressants. However, sodium hydrosul fide can be used preferably if economic, operational, and environmental factors are taken into consideration.

Jan 1, 1983

By J. V. G. Middleton

The paper gives a comprehensive review of the design considerations which determined the choice of the milling plant, a description of the plant and comment on the operating experience to date. Operating experience will include inter alia a description of the mill liners installed with subsequent changes due to wear patterns, the mill inlet sealing arrangement, steel ball addition, mill outlet sump design, cyclone feed pump liner wear patterns and comment on the efficiency of the linear screens for wood chip and tramp removal. Finally a view on future trends in South African milling practice with respect to type and size of plant.

Jan 1, 1989

By Vivek Priyadarshi, VIVEK KUMAR HIMANSHU, A. K. Vishwakarma, M. P. Roy, A. K. Mishra, RAVI SHANKAR

The nature and orientation of joints in rock strata affect the damage pattern under explosive loading. Most of the limestone deposits in India are found with severity of joints. Categorically, these joints may have variable orientations such as dipping out of the blast face, inside the face, horizontally or having strike parallel to the face. The damage pattern under the varying category of orientation will be different. Accordingly, a numerical model in Ansys-Explicit Dynamics was prepared to compare the damages of rock mass under different joint orientations. The physical nature of a joint reflects frictional and stiffness behaviour. Accordingly, the damages have been compared under bonded and frictional nature of joints. The output damage pattern from the model has been validated on the basis of blastability index proposed by Lilly. Different limestone mines in India show different nature of jointing in their rock strata. Accordingly, the blasting outputs from three different limestone mines, viz. Rawan limestone mine, Sagmania and Birhauli limestone mine and Injepalli limestone mine, have been compared along with their blast design parameters and the nature of joint. The comparative results show that the closely spaced horizontal joints support maximum in burden movement and rock fragmentation due to blast.

Nov 23, 2023

By M. Westerstrand

It is known that the water chemistry of the process water during ore refinement can affect product quality, such as iron pellet strength. The main objective of this study was to quantify the amounts of major elements, such as Ca, Mg, Na, S and Cl carried by process water and by magnetite grain surfaces to the end product, iron ore pellets made from magnetite ore from the Kiirunavaara Mine in northern Sweden. In addition, the amount of colloids (0.22µm ? 1kD) in the process water was examined by ultrafiltration. The amounts of various elements sorbed to the magnetite surfaces were estimated by leaching with Milli-Q water, MgCl2, NH4-acetate and Na-acetate. Total dissolved solids were between 1,446 and 1,775 mg/l, dominated by Ca, S, Na and Cl (89%). The colloidal fraction was less than 3% for major ions. For Ca and Mg, sorption to magnetite surfaces was a much more important transport mechanism for the pelletizing process than evaporated process water, but for Na, Cl and S process water was an important carrier.

Jan 1, 2010

By M. Sadegh Safarzadeh, Erich U. Petersen, Jan D. Miller

"An acid bake-leach process has been identified and applied to an enargite concentrate containing ~67% enargite, ~27% pyrite (FeS2), ~3% chalcopyrite (CuFeS2), ~6% sphalerite (ZnS) and <1% galena (PbS). Sulfuric acid baking of this concentrate resulted in the transformation of the concentrate to S8, As2O3, HFe(SO4)2•4H2O, PbSO4 and Cu0.47Fe0.53SO4•H2O, all of which (except elemental sulfur and PbSO4) dissolved during the water leaching step. More than 87% Cu and 64% As were leached when the concentrate was baked at 200°C over 7 hours with a sulfuric acid-toconcentrate weight ratio of 1.6. Less than 1% As was lost to the gas phase. Upon water leaching, copper and arsenic were released to the solution at a concentration ratio of about 3:1. While enargite is very reactive during the sulfuric acid baking reaction, other minerals present in the concentrate such as pyrite, galena and sphalerite may compete to consume sulfuric acid and be converted into their corresponding sulfates at different concentrations. The purpose of this paper is to present our examination of the effects of sulfuric acid dosage on the extractions of Cu, Fe, and As from an enargite concentrate. In this regard, the concentrate, baked concentrate, and the leach residues are characterized and a conceptual process flowsheet is described for the acid bake-leach process for the treatment of enargite concentrates.IntroductionThe occurrence of enargite (Cu3AsS4) in copper ores and concentrates and the associated high arsenic values in such resources have resulted in a considerable decrease in the demand for such concentrates because they cannot be economically processed using conventional technologies such as smelting and atmospheric leaching (Mihajlovic et al., 2011). The exploitation of such problematic deposits through competitive treatment strategies will be required in the near future in order to satisfy increasing pressure from the copper market. It is expected that the average arsenic grade of copper concentrates will increase from 0.17% in 2008 to 0.22% by 2020 (Mayhew et al., 2011).The acid bake-leach process was identified and selected for further investigation at the University of Utah as a possible process alternative for the treatment of enargite concentrates. In this case, adequate amounts of concentrated sulfuric acid are mixed with the concentrate and heated to the temperature range 150-300°C. Subsequently, the baked material is leached with water/weak acid and the acid bake-leach process has some advantages over conventional sulfuric acid leaching (Prater et al., 1970). During water leaching, metal sulfates are released in solution, after which they can be extracted through well-known hydrometallurgical techniques. While the majority of the work has been done on oxide minerals, there is a limited record of sulfuric acid baking of sulfides."

Jan 1, 2015

By T. T. Toomver

The evolution of Inco&apos;s Selective Reduction Smelting Process as practised today is described, beginning with the initial laboratory experiments on small samples to the processing of large bulk samples through pilot plant equipment. For both the Guatemalan and Indonesian (Soroako) ores, the initial screening tests using hydro-, vapo-, and pyro-metallurgical processes showed that the latter was the most promising both metallurgically and economically. Later, larger scale tests confirmed the earlier testwork.

Jan 1, 1979

By C. Y. Chen

Public Law 75-87, the Surface :mining Control and Reclamation Act of 1977 (SMCRA), Section 516(b) requires the underground coal mining operator to "adopt measures consistent with known technology in order to prevent subsidence causing material carnage to the extent technologically and economically feasible, maximize mine stability, and maintain the value and reasonably foreseeable use of such surface lands, except inn those instances where the mining technology used requires planned subsidence in a predictable and controlled manner . . .?. The Congress also directed the Secretary of the Interior to promulgate regulations to implement the law. As a result, the control of subsidence from underground coal mining to minimize surface damage has become the mandate of a Federal law. This paper discusses the mechanics of subsidence and the effects of subsidence on ground features and also summarizes some of the measures which have been used to minimize the possibility of damage to surface structures as a result of subsidence due to underground coal mining.

Jan 1, 1981

By B. Whisner, A. Smith, J. Carr

"Electromagnetic based proximity detection systems (PDSs) are utilized on mining machinery to protect workers from being pinned or struck. These systems generate magnetic fields covering the space around a machine, and a miner-wearable component (MWC) detects the field. The PDS determines the distance of miners relative to the machine based on the detected magnetic flux density in the magnetic field. This information is used to establish warning and shutdown zones around the machine. Maintaining a stable magnetic field is essential for system accuracy. However, components used to generate magnetic fields can be influenced by temperature changes. Depending on ventilation conditions and seasonal alternation, a PDS can be subject to significant temperature fluctuation. To better understand and quantify this phenomenon, researchers from the National Institute for Occupational Safety and Health (NIOSH) developed an experimental apparatus to study the influence of temperature on magnetic field generator circuits used in PDSs. Results from the study show that the electric current through a generator can be influenced by both ambient and internal temperatures, modifying the magnetic field that is produced. These findings show that temperature can significantly influence the ability of PDSs, used in underground coal mines, to accurately determine a worker’s position in relation to mining machine. INTRODUCTION Electromagnetic based proximity detection systems have been developed to reduce machine-related accidents in underground coal mines. The first proximity detection systems installed in underground coal mines were developed for continuous mining machines (CMMs). There are five of such proximity detection systems that are approved for use in U.S. mines by the Mine Safety and Health Administration (MSHA) (Mine Safety and Health Administration, 2013; Mine Safety and Health Administration, 2015). There are several basic components that interact within an electromagnetic proximity detection system (PDS). A PDS includes two main elements: a set of generators to create magnetic fields around a CMM and a set of magnetic probes to detect the fields. These systems can determine if a miner is located at a safe distance from the machine based on the detected magnetic flux density. Stability of the magnetic fields is essential for system accuracy."

Jan 1, 2018

By Peter G. Zambas

In planning an underground room and pillar mine, the selection of the shaft or portal location and the orientation of the main haulage arteries is of paramount importance, particularly in view of the high dependence of the cost of truck haulage on the proper definition of these parameters. In an effort to facilitate this selection a computer program was written which, by relating the truck characteristics to the areal configuration of the property or ore-body, derives the volume-weighted total fuel and time requirements for hauling ore from every panel within the property to a specified portal or shaft location through a predetermined gridwork of haulage drifts. By varying the size and orientation of the gridwork and the location of the portal or shaft access, an infinite number of configurations can be investigated. The results of this analysis can be plotted to indicate the optimum conditions.

Jan 1, 1971

By Elimame Elaloui, Kais Elghniji, Constantin Virlan, Aurel Pui, Chaima Ouled Amor

Separation and identification of minerals composing the Tunisian silica sands have been conducted by acid etching and hot filtration/sedimentation (HFS) without affecting the quartz component. It was found that the hot acid etching process is an effective method to separate quartz and clay minerals in the silica sand. The SEM micrographs of the silica sand show rough surface and some cracks with irregular shapes. The surface becomes clean and smooth after acid etching process. After chemical dissolution, the clay minerals were recovered by hot filtration following by sedimentation at low temperature. FT-IR, EDS maps, and secondary electron (SE) analyses of separated clay minerals reveal the presence of Fe2O3, montmorillonite, and kaolinite minerals. The LIBS analysis of clay minerals shows the presence of Al, Fe, Ca, Al, and Mg. The sequential etching process can be introduced in the purification methods as an effective way to separate quartz from clay minerals.

Jul 29, 2020

By Harvey P. Knudsen

This paper illustrates the application of geostatistics to a roll front type uranium deposit located in Wyoming. The steps involved in calculation of experimental variograms, variogram modeling and verification of the resulting models are described in detail. The resulting spherical variogram models for grade thickness and thickness show strong geometrical anisotropies. The major axis of anisotropy for both variables is approximately parallel to the axis of the roll front and the minor axis perpendicular to the roll. This model confirms the technique of drilling "fences" across the roll front, where the drilling is much closer together than the fences along the roll.

Jan 1, 1978