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By N. F. Sather

Results of comprehensive trace element analyses of samples of Illinois #5 and #6 seam coals and the unquenched ashes obtained from gasification of these coals in a Lurgi reactor are reported and discussed. Areas where additional background information is needed for assessment of the environmental impact of trace element emissions from coal gasification are identified.

Jan 1, 1976

By CADEN VITTI, Barbara J. Arnold

Mine tailings, the byproduct of mining and mineral processing, are increasingly mass produced as a result of increased demand for metals and minerals as well as the advancement in technology that allows for the exploitation of lower-grade ores. Lower grades can increase the volume of tailings that may contain new gangue minerals that should be evaluated for the presence of critical minerals and other valuable metals. The practice of reprocessing, while relatively new, is crucial to reducing environmental damages, obtaining valuable critical minerals from waste, and contributing to more sustainable repurposing and disposal methods. With the increase in tailings dam failures in recent years, there is a large motivating factor in remining and removing the potential hazard to benefit the safety of potentially impacted communities. In analyzing the perspectives of various domestic and international studies, this literature review will determine the feasibility of reprocessing and reutilizing mine tailings waste for a more sustainable future while exploring current practices that have benefitted ecosystems and communities.

Jan 1, 2022

By Göksel Hızlı, Selim Ertürk, Ayşegül Bilen, Raşit Sezer, Cüneyt Arslan

The carbothermic reduction of celestite is the first step in producing many strontium products. The way materials move in the rotary kiln has an essential effect on the carbothermic reduction efficiency as well as the temperature. In this study, the reduction of celestite ore and excess carbon blend in a laboratory-scale rotary kiln was investigated. In the experiments carried out at three different temperatures, the rotational speed and slope of the furnace tube were altered, and their effects on the reaction efficiency were examined. The leachability of the reduced powders and the content of the unburned coke indicated the optimal parameters for the reaction.When the speed was increased to 10 rpm, the powders weremoremobile in the stack and could react more easily with the furnace atmosphere. According to the results, celestite can be reduced by carbon at temperatures of 1000–1200 °C, at rates of between 5% and 75%. The maximumreaction yield (75%) was obtained with a slope of 2° and a rotational speed of 6 rpm at 1100 °C.

May 7, 2020

By Edwin R. (Original by) Phelps

Surface mining refers to the process of removing the material (over- burden) overlying a coal seam and exposing the coal so that it can be loaded out and conveyed by trucks or other methods to the preparation plant or other facility. Surface mining has not always been important in the coal industry. In the early 1900s, almost all of the coal mined in the United States was mined by underground methods. In 1900, about 192 Mt (212 million st) of bituminous coal were mined and less than 1% was mined by surface methods. The development and use of larger equipment has allowed surface mining to gain prominence throughout the years. Table 1 shows the total production of coal by mining method in the United States for ten-year periods since 1920 and indicates the growth of surface-mined coal production. Surface mining will undoubtedly continue to account for a large percentage of the coal production in the US for many years because: 1) The capacity of surface mining excavators has continued to increase. Today, mining companies are using shovels (see Fig. 1) which are able to move up to 137.6 m3 (180 cu yd) in each bite and draglines (see Fig. 2) which move up to 168.2 m3 (220 cu yd) in each bucketful. 2) Increasing tonnage from the thick western coal seams is being produced by surface mining methods. 3) Surface mining has normally had lower costs and a better safety record than underground mining; 4) Surface mining normally recovers a- much higher percentage of the coal reserve than can be recovered by underground mining. 5) Some coal measures can best be extracted by surface mining [ ] methods because of geologic reasons such as the nature of the roof or bottom, thickness of the seam, multiple bedding, etc.

Jan 1, 1981

By Steven E. Mischler, Jay F. Colinet

The study analyzes the impact of the Continuous Personal Dust Monitor (CPDM) on reducing overexposures to coal mine dust. It compares compliance sampling data before and after the implementation of the CPDM and the 2014 MSHA dust rule. The results indicate a significant reduction in the percentage of samples exceeding the dust standard for various mining occupations, highlighting the effectiveness of the CPDM in improving miners’ health and safety.

Feb 22, 2022

By Frank E. Sullivan

The separation of liquids from granular materials has been widely studied by a number of: investigators over a period of years in an effort to more fully understand the physical phenomenon which occurs. Liquid may be removed from solids, or partially removed, by gravity separation, mechanical separation' or heat drying. Mechanical separation is advantageous when compared to heat drying principally from a cost saving standpoint and also on certain materials which are heat sensitive. It is realized however that mechanical separation of liquids has certain practical limitations. In order to evaluate the efficiency of mechanical separation and predict the extent of, liquid removal, it is first necessary to study the forces which hold the liquid to the solids. From a very practical observation using gravity drainage, it is soon obvious that a pile of coarse solids will drain faster and retain less liquid than a pile of finely divided solids of the same material. For commercial operations it is important to estimate the residual liquid which will remain after a mechanical separation. Batel (1) explored the various quantities of liquid present in the interstices of the bulk granular material. From his work and other authors which he has correlated in one of his recent papers, various formulas are now available which permit an empirical relationship to be developed showing residual moisture versus mechanical separating forces.

Jan 1, 1965

By Fernando Jorge Dick

Artificial sulphides have been produced on the surfaces of heavy metal-oxide, minerals at elevated temperatures (1) and these sulphides gave consistently similar flotation characteristics as the respective natural sulphides. In the case of tin, the only natural tin sulphide known is herzembergite (SnS) which is found only in minor quantities, and its flotation behavior is not known. Balberyszki, Dorenfeld, and Carmi reported (2) tests with artificial tin oxide and pure cassiterite treated with hydrogen sulphide at temperatures above 750oc. They confirmed that the product could be floated in acid pulps. However, iron sulphides derived from pyrite, limonite, and hematite which are generally the major impurities in tin bearing ores could not be separated from tin sulphides under the conditions used by previous investigators. As a practical matter, if complex tin ores or complex low grade tin concentrates are to be treated by this process, it is necessary to be able to separate sulphidized cassiterite from other sulphidized minerals in the feed. The major metallic minerals, by weight, in complex tin ores are the iron minerals--pyrite, hematite, limonite, magnetite and pyrrhotite. These minerals become (or remain) sulphidized during the sulphidization process.

Jan 1, 1978

By Samuel S. Adams

The Permian Salado Formation of west Texas and southeastern New Mexico is composed of halite and subordinate amounts of anhydrite, clay and potassium and magnesium-bearing evaporite minerals. Aspects of the geochemistry of the Salado Formation have been investigated through studies of the stratigraphy, mineral assemblages, textures and minor element content of the salts. These studies provide information on the origin of the evaporites when combined with data on equilibria in saturated salt solutions. The principal potash ore zone in the district is composed essentially of halite (NaC1) and sylvite (KC1). Data on the color, bromide content, and proportions of halite and sylvite suggest that this simple assemblage is the product of a series of replacements rather than primary precipitation. The bromide content of the salts also indicates that the brine which precipitated the Salado Formation was derived from the dissolution of older evaporites rather than the simple evaporation of sea water.

Jan 1, 1966

By Zsolt Csillag, Dragorad Ivankovic, Miomir Ceh, Anna Csordás-Tóth

Results of the common research work of ALUTERV-FKI and RI in field of ore dressing are presented here. Although monohydrate types of bauxites consist of finely dispersed minerals, however, in some cases certain contaminants (carbonates mainly), can be reduced by physical methods before Bayer process. Electronmicroscopy combined with computerized data processing is proven to determine the possibility of beneficiation and to control the different stages of ore dressing. Test results gained by Hungarian and Yougoslavian bauxite samples, contaminated by calcite, dolomite, siderite and pyrite, are discussed. Basic operations were: grinding (mostly dry) and classification, magnetic separation (mostly wet) and selective agglomeration. Only simple processes, having high efficiency and mostly dry ore dressing technique may meet the requirement of economical criteria. 1. [CONDITIONS OF ADAPTING THE BAUXITE DRESSING METHOD] Bauxite is a relatively cheap raw material, occurring in great bulks. Bauxite deposits may often lay far from the traditional ore processing plants, and in such cases the ore reaches the plants after long transportation. Some of these plants must face the difficulty that the resources of high quality ore are exhausted, they fall short of supply and, consequently, they must decide on whether to utilize the existing resources of poorer

Jan 1, 1984

By H. J. Hutson

BRS, Inc. has utilized Carlson's Natural RegradeTM software to design the reclamation and stabilization of abandoned open pit uranium mine spoils, AML Project 16N, located in the Gas Hills Uranium District in central Wyoming. This work was completed for the State of Wyoming's Abandoned Mine Land Program (AML) on preSMCRA (Surface Mining Reclamation and Control Act) sites for which no reclamation obligation existed. The project successfully stabilized an eroding spoil dump, enhanced the local view shed, created habitat diversity and provided a significant source of fill material for open pit highwall hazard mitigation efforts. Additionally, the project served to evaluate innovative reclamation design methods, engineering software and grade control technology. This project was nominated for a National Association of Abandoned Mine Land Programs award by the State of Wyoming. The results of this project will be presented as a case history of the Natural RegradeTM approach to surface mine reclamation. Based on the successful application of this new mine reclamation technology on the AML 16N Project, reclamation designs for spoils associated with planned underground uranium mine operations at the Velvet Mine in the Lisbon Valley Uranium District of Utah for Uranium One USA, Inc have been prepared and will be presented. Critical elements will be the encapsulation of unsuitable materials, long term hydrologic stability, and sequencing and staging of ore and mine waste for final reclamation surface construction. The goal of the Uranium One Velvet Project will be to apply best available technology to reclamation planning and fully integrate the reclamation design with the mine planning. Benefits of the approach should include improved public and regulatory perception of the project, facilitate mine permit approvals and the eventual timely release of reclamation bonds, as it is anticipated the stable landform created through this process will result in more rapid stabilization of the site to pre-mine geomorphic conditions. NATURAL REGRADETM CASE STUDY AML Project 16N, D-9 and K Pit Reclamation Project, is located in an intensely disturbed area of the West Gas Hills Uranium Mining District in Fremont County, Wyoming. The overall design calls for the placement of approximately 7 million cubic yards of backfill materials in the D9 and K Pits, imported from adjacent mine spoils including the Central Spoils, and from local highwall excavation. Figure 1 shows the location of the Central Spoils excavation area, as well as the D9 and K Pits fill area. The entire project is located on public lands administered by the Bureau of Land Management, Lander, Wyoming District Office. No access controls are in place at the abandoned mine sites. The public lands are administered under a multiple use land policy including grazing of range land, public recreation, active mining and exploration, and oil and gas. The project site is located along Fremont County Road No. 5, which is a moderately well traveled road. Reclamation of the numerous and large abandoned open pits in the Gas Hills Uranium District has reduced the risk of death or injury to the public. Site History and Background The Gas Hills Uranium District was mined by multiple companies during the period from 1955 to 1981. The uranium was hosted in the Wind River formation, a sequence of soft sedimentary layers of interbedded sandstone, clayey shales, and conglomerates. Uranium was precipitated out of ground water in classic roll front deposits, which are found from very near surface to depths greater than 400 feet. Prior to the enactment of the Surface Mining Control and Reclamation Act of 1977 (SMCRA), very little reclamation work was performed when mines were abandoned or closed. The State of Wyoming Abandoned Mine Lands Program has worked to mitigate hazards associated with large open pits, control migration of unsuitable materials and restore watershed functionality of lands in the district. Additional reclamation is being performed by mining companies on bonded lands. Figure 2, Gas Hills Uranium District aerial photograph, shows the extent of the mining disturbance in the district. [ ] Project Hazards and Concerns The purpose of AML Project 16N is to mitigate hazardous conditions and risk to the public associated with open pit highwalls and toxic, acid forming, and /or radioactive mine waste materials. The D9 and K Pits are contiguous open pits characterized by an 8,800 foot long hazardous highwall that averages over 200 feet tall. In addition to the physical hazard presented by the highwall, the project addresses

Jan 1, 2009

By I. Iwasaki

Differential flotation of bulk sulfide concentrates from Duluth gabbro into copper and nickel concentrates could be implemented by first destroying the hydrophobic coating with ozone and then by recovering the copper concentrate with a copper-selective collector. A number of parameters involved in the use of ozone; such as the sequence and the conditioning time of ozone treatment, the pulp pH, and the level of xanthate addition, were investigated.

Jan 1, 1985

By Jamal Rostami, Manso Deen Sesay, Sydney Slouka, HUGH MILLER, Anshuman Mohanty, Midhat Sajad, Kun Zhang

The lack of progress in controlling pulmonary diseases such as pneumoconiosis cases in recent years necessitates additional studies on dust generation and the characterization of airborne dust. Studies are underway by a NIOSH-sponsored project to observe the characteristics of the dust generated by pick cutters under various wear levels. This research performed a full-scale linear-cutting-test matrix on eight coal samples with various bit penetrations, spacing, and wear conditions. The specific energy and resulting PSD (particle size distribution) of airborne dust and material left at the cutting surface were measured and analyzed. The dust concentration was determined using the NMAM (NIOSH Manual of Analytical Methods) 0600 method. For fines, the PSD was characterized using Laser Diffraction, measuring percent channel and aerodynamic diameter, while Imagej, a virtual sieving application, was used for larger particles. The results show that for a new bit, as the cutting depth and spacing increase, the specific energy and dust generation decrease. The size and shape of the dust particles have been analyzed, and the observed trends are discussed in this paper.

Feb 1, 2025

By Frederico J. Price

This paper describes the production of a specific iron oxide pellet that has given very good and consistent results as feedstock for HYL-Process Direct Reduction Plants. The sponge iron originated from these pellets has been used for the economic making of almost 15 million tons of low carbon steel via electric arc furnace meltshops. An overview of mining, benefication, pelletizing direct reduction and steelmaking for this case is given with emphasis on the characteristics of the self-fluxing oxide pellets. HYL Operator and management training is described.

Jan 1, 1979

By I. J. Dowdeswell

Perspective Man is a model maker. Throughout recorded history man has-used models both to provide insights into the workings of the processes which surround him and as a step towards the eventual control of those processes. These models have covered the field from extremely large systems (solar and celestial. models) to infinitesimally small systems (sub-atomic .and atomic models). Models have been developed for social systems, ecological systems, biological systems and economic systems: all fields of human endeavour contain the fruits of this restless model-making. The Role of Models Since the evidence of mans' industry in formulating models is so abundant, it is worthwhile stating some of the reasons. Based on the simple definition that "a model is a convenient and useful representation of some facet of the 'real' world", then a model provides a means for: 1. Understanding the thing being studied. 2. Communicating that understanding to others. 3. Manipulating the thing being modelled. The common denominator implicit in these reasons is that- improved control is the. objective off all modelling or simulation work. Improved control shows itself either directly by the development of devices which perform the control functions or indirectly by improvement in the decision making process itself. For example, in a process plant, a suitable model of part of the process could lead either to the use of automatic control devices such as set-point controllers or to the implementation of instructions (pre-defined decisions) which permit the operator to better control the process. Typical process control systems use both of these since fully automatic control is restricted to processes where the required information can be effectively measured.

Jan 1, 1972

By Thomas Novak, Sampurna Arya

Controlling dust generation and keeping it below permissible limits to meet federal dust standards at the working face of a roomand-pillar coal mine is a challenge for a mine operator. With the recent changes in federal dust regulations requiring lower worker exposure, maintaining compliance has become increasingly difficult. The current most effective practice of dust control at a continuous miner face in an underground mine is the use of a flooded-bed scrubber. A study carried out by the National Institute for Occupational Safety and Health (NIOSH) indicated that a flooded-bed scrubber could achieve cleaning efficiencies between 58 and 90%. But, the operation of such a system is maintenance intensive. The flooded-bed scrubber screen becomes clogged with dust particles and requires frequent cleaning to maintain performance. However, the dust control issue is not solely a mining industry problem. Other industries face similar issues. The University of Kentucky collaborated with Toyota Motor Manufacturing on the development of a novel wet scrubber, called the vortecone scrubber, for capturing oversprayed paint particles in automotive paint booths. The vortecone scrubber achieved a cleaning efficiency of 99% and required minimal maintenance. This study aims to assess the ability of this vortecone scrubber to capture respirable dust in an underground coal mine. The paper presents the results of computational fluid dynamics (CFD) modeling of this vortecone scrubber. It discusses the effects of air quantity and dust particle size on the performance of the scrubber.

By M. S. Klima

Proper analysis of washability data can lead to the development of a maximum yield coal preparation plant flow sheet. Simulations, as simple as spreadsheet mass and water balancing, are important in examining yield maximization and middlings liberation. Key to such attribute tracking flow sheet simulations is the distribution model, expressing the probability of a species reporting to the product stream. There are many such models in the literature. This paper examines a functional form that can represent or fit most of the proposed distribution functions.

Jan 1, 1997

By Dominique Francois-Bongarcon

The world mining industry is facing a severe recession. Thus, it is time to recall the value of geostatistical methods which were formerly developed as a money-saving and productivity-increasing tool. The situation has worsened, but the techniques of geostatistics have dramatically changed. Up to millions of dollars can be saved during exploration with simple use of variograms; then, during reserves estimation with kriging methods; and finally, with the parameterization of reserves, when evaluating a project and optimizing its global mining parameters.

Jan 1, 1983

By L Usoni

Collectors commonly used in flotation to date fall into two main classes: ionic and nonionic. The use of neutral or oily collectors is generally limited to the flotation of nonpolar minerals onto which they are adsorbed by forces of a physical or 'Van der Waals' type, while ionizable chemical collectors are utilized for all other types of minerals, adsorption in this case involving bonds essentially of a chemical nature. Though chemical adsorption is more selective than physical adsorption, even heteropolar collectors are active towards certain classes of minerals (sulphides for example) rather than towards one individual mineral. Thus, in order to float a given mineral from a mixture of minerals belonging to the same class, modifiers have to be used to render the action of the collector more specific. However, there are often considerable difficulties involved in this procedure and the desired results are not always attained, especially in the case of minerals of complex composition whose surface properties are not sufficiently well known. Hence the importance of seeking out collectors capable of linking selectively with given minerals. Selective linkage is possible if the collector structure incorporates active groups having specific affinity for certain cations characteristic of the mineral surface. The decision to investigate the possibility of utilizing chelate--forming reagents for flotation was based on the premise that phenomena which occur in solution and involve chemical reactions in the strict sense of the meaning and those which occur on the surface are closely correlated (1)

Jan 1, 1971

By Susanne Pignolet-Brandom

Flash smelting products of a copper sulfide concentrate collected at successive levels in an experimental reactor have been studied by reflected light microscopy, scanning electron microscope - energy dispersive analysis and electron nicroprobe analysis. Chalcopyrite, intermediate solid solution, bornite, chalcocite, metallic copper, magnetite, iron-copper spinel, pyrrhotite, hematite, delafossite and cuprite have been identified in the product samples. The detailed reflected light microscopy study of these phases and their abundance in the samples has resulted in the identification of the series of reactions during flash smelting.

Jan 1, 1985

By ANGELA NAIR AVELAR, Reiner Neumann, PAULO R. G. BRANDÃO

Three types of apatite were identified by means of cathodoluminescence (CL) images in flotation concentrate and tailing samples from the Catalão Mine in Brazil. They are predominantly blue apatite, followed by green apatite and, less frequently, yellow apatite. The chemical compositions of these types of apatite were determined by electron microprobe analysis and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). Blue and green apatite responded well to the process, thus remaining in the concentrate, while yellow apatite remained in the tailings. Yellow apatite has the lowest phosphorus pentoxide (P2O5 ) content and largest anionic and cationic sites substitution, followed by green apatite, whereas blue apatite is the most homogeneous, with highest phosphorus (P) and calcium (Ca) grades and lowest substitution level.