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By Drew Hobert, John Nielson, Erich Dohm

Metallurgical coal is an essential component for the blast furnace-basic oxygen furnace (BF-BOF) steelmaking process, which accounts for roughly 70% of total global steel production. To meet the growing demand for metallurgical coal, Arch Resources identified the potential to recover low- ash coal from ultra-fines discarded prior to the deslime flotation circuit across their portfolio of operations. Historically, many flotation circuits were designed to discard this ultra-fine coal due to high clay content and technological barriers to cost-effectively upgrade and dewater the coal to a saleable product. Recent advancements in high-intensity flotation technology, including the Eriez StackCell, have enabled coal producers to recover ultra-fine coal while minimizing capital and operating costs. In July 2023, Arch Resources commissioned the first full-scale ultra-fines recovery circuit utilizing StackCell high-intensity flotation technology at the Leer Mining Complex. This paper reviews the approach utilized to develop the flotation process design, learnings from the commissioning and ramp-up period, and performance data through the first year of operation.

Feb 1, 2025

By D. G. Kotlyar

Oxidized sulfide minerals, commonly formed by weathering, increasingly are becoming important resources as primary sulfide deposits are depleted. Oxidation, in general, reduces selectivity and recovery in flotation. The objective of this research was to determine the mechanisms of oxidation and collector adsorption in sulfide systems as a step towards developing improved technologies for beneficiation of oxidized sulfides. Data from microcell flotation tests are combined with electrochemical and spectrophotometric measurements. The adsorption of ethyl xanthate (EX) on oxidized sulfides was characterized using AC impedance techniques and correlated to flotation response. The floatability of chalcocite, chalcopyrite and pyrite was dependent on the extent of oxidation. Oxidation for 1?) d at 65? C inhibited flotation of chalcocite, and chalcopyrite even after the addition of a large amount (1 x 10') M) of collector. Heavily oxidized (27 d) chalcocite remained unfloatable. However, longer oxidation of pyrite and chalcopyrite restored the floatability. Oxidation resulted in an electrically resistive, nonporous surface layer.

Jan 1, 1993

By S. T. Hall

The authors have previously described a method of enhancing the magnetic susceptibility of pyrite by a mild alkaline oxidative pressure leach (Hall et al, 1985). This finding was successfully applied to enhance the magnetic desulfurization of an Eastern Canadian coal (Hall and Finch, 1984). This paper reports on enhancement of the magnetic susceptibilities of iron-containing sulfides (arsenopyrite, chalcopyrite and marcasite) upon similar treatment. It also explores the application of this pretreatment in the magnetic separation of fine sulfides from oxides and other sulfide minerals. In the latter case galvanic interference effects have a serious impact on the potential use of this method.

Jan 1, 1985

By Ray E. Harris

New developments have occurred in Wyoming's industrial minerals industry since the 32nd Forum on the Geology of Industrial Minerals in Laramie, Wyoming in 1996. The soda ash trona and bentonite industries have experienced overall growth. Gypsum and limestone production have remained constant, but have the potential for dramatic growth. The mining of zeolite ceased in 1997. The struggling dimension stone industry has increased production, but development has lagged behind the schedule predicted in 1996. The construction of a container glass plant and associated production of glass raw materials, as predicted in 1996 and imminent in 1998, is now on hold due to unforeseen market factors. Increases in railroad and highway construction have, and will, greatly increase the production of construction aggregate for local uses. An iron carbide industry, not foreseen in 1996, is in the planning stages.

Jan 1, 2001

By James E. Myers

This study is a survey of the current "state-of-the-art" of commercially-available sonar tools to monitor the true shape of man-made cavities within the Hutchinson Salt of south-central Kansas. The work entailed ferreting out the available information, most of which is proprietary in nature; then examining actual existing conditions and arriving at a reasonable scientific evaluation of the method. Our studies were confined to one LPG field and two brine well operations in south-central Kansas. No field testing of any devices was performed, only questioning user firms, and studying cores, logs, and sonar surveys graciously made available by the companies we have contacted. Since these data are still somewhat proprietary, the company participants have asked that their company names be omitted from this presentation.

Jan 1, 1973

By Harvey P. Knudsen

Case studies are presented in this paper to illustrate the usefulness and applicability of using conditional simulation in under- ground coal mine planning. Conditional simulation is a technique developed in the last five years that allows the building of a simulated ore body (or coal deposit) model. Construction and validation of the simulated model is described in order to show how well the model reproduces the essential characteristics of the deposit. In the model, the thickness, ash, and sulfur content are known everywhere in the deposit and each variable has the same mean, variance, and spatial variability (variogram) as that variable has in the real deposit. Use of the simulated deposit in the design of drilling strategy for long range mine planning is demonstrated in me case study. Determining the potential of short term production scheduling to reduce the fluctuations of sulfur in run of mine coal is described in the second case study.

Jan 1, 1980

By Abhilash, S. Sarkar, T. Venugopalan, P. Meshram

"To explore blast furnace slag as a secondary resource for rare earth elements (REEs), blast furnace slag containing lanthanum (La), cerium (Ce), erbium (Er) and neodymium (Nd) in concentrations of 17, 16, 4 and 44 ppm, respectively, was processed with sulfuric acid while optimizing the parameters of acid concentration, temperature and pulp density. The experiments showed that recovery rates of 92, 36, 35 and 52 percent for La, Ce, Nd and Er, respectively, were achieved at 1 to 5 weight/volume (w/v) percent pulp density using particles smaller than 250 µm and treating with 1 M sulfuric acid for one hour at room temperature. Raising the temperature to 95 °C promoted the dissolutions of Ce and Nd to 89 and 84 percent, respectively, for the same 1 M acid concentration and one-hour duration at 5 w/v percent pulp density. Cyanex 923 was preferred over Cyanex 301 for the purification of REEs from leach liquor. In another route, the leach liquor was subjected to precipitation with 0.5 to 1 M oxalic acid, resulting in a product with 4 to 5 percent concentration of REEs.IntroductionRare earth elements (REEs) are important materials in numerous high-technology applications, but they have high supply risk, giving rise to the study of new sources. The recycling of REEs has been well researched, especially on a small scale, but has not been widely implemented. Less than 1 percent of REEs were recycled in 2011 (Binnemans et al., 2013). REEs occur in a large number of minerals in oxidic compounds, such as oxides, carbonates, phosphates and silicates, and are present as mixtures at 10 to 300 mg/kg concentrations in many rock formations, such as basalts, granites, gneisses, shales and silicate rocks. The most abundant REE in the Earth’s crust is cerium (Ce), at a concentration of 20 to 70 mg/kg, followed by neodymium (Nd) and lanthanum (La), with heavier REEs being less abundant (Binnemans et al., 2013). REEs occur in nature in their oxidized forms in salts and minerals due to their electropositive nature and high affinity for oxygen. The possibility of recovering REEs"

Jan 1, 2017

By J. Marsden

Lift height, overall heap height and climate all play an important role in determining precious metals leaching rates, recoveries, operating costs and capital cost requirements for heap leaching operations. The effects of these factors are not easy to predict from testwork, and this can result in unexpected delays in metal production, lower recoveries than expected and higher capital and operating costs than necessary. This paper investigates the economic impact of lift height, overall heap height and climate on heap leaching and provides criteria to assist in the design and operation of leaching facilities. Descriptions of three heap leach operations in the western USA are provided to support the discussions and conclusions.

Jan 1, 1995

By A. Leppala

Scope of the Courier 300 System The fact that reliable on-stream analysis is a prerequisite for effective flotation control is hardly disputed today. Nevertheless, up to now no system has been available that includes all the equipment necessary for successful analysis. However essential an on-stream analyser is in itself, reliable and accurate assaying can only be assured after techniques for sampling, handling the slurries and computing the X-ray data have been developed for the purpose. The Outokumpu Company's Courier 300 System is a complete package that can be installed and handed over with the key. It includes the equipment needed for sampling and handling the slurries. It has been developed from the start to meet industrial demands. Obviously an on-line system must comply with far stricter standards than one designed for a laboratory. Assays are computed by an Outokumpu 316 digital data processor, which is an integral part of the system and controls its entire performance. The computer software is programmed as a standard package, including a highly advanced new model for assay computation. Analysis output is available for a process computer, report typewriter:, and recorders. The package also includes calibration for slurry assays at our pilot installation before delivery. A complete Courier System can analyse up to 4Z slurries and six elements in each slurry. Thanks to its modular design, it can be dimensioned initially to the customer's requirements and is easy to expand later at low cost. Being a mining company itself, Outokumpu has been able to utilize its own long experience in non-ferrous metallurgy - an important factor contributing to the success of the Courier system. History of the project and present installations The first on-stream analyser was installed at Outokumpu'a Pyhasalmi Con¬centrator at the end of 1967, after several years' development. Since then,

Jan 1, 1971

By R. J. Sweigard

Many states are considering the need to establish or modify policy relating to the disposal of coal ash. One of the primary concerns is the impact of leachate from the ash disposal sites upon groundwater and nearby bodies of surface water. A detailed site investigation was conducted at a coal ash disposal facility associated with a power generation station. The disposal site is situated alongside a major river. Monitoring wells were installed and soil samples were taken for characterization. Groundwater models were used to simulate migration of leachate from the disposal site toward the river. Such models could be used potentially to verify regulatory compliance. This paper addresses the validation and adaptability of these models to this case and their usefulness as possible tools to be used in future environmental audits.

Jan 1, 1992

By J. G. Asbury

Broadly conceived, the demand for electricity depends upon three sets of variables: (i) the growths of the many individual demands for energy services; (ii) the competitiveness of electrically driven technologies in meeting these demands; and (iii) the energy-conversion efficiencies of installed electrical technologies. The first set of variables establishes the size of the potential market; the second, the market penetration of electrical equipment; and the third, the quantity of electricity required to operate the equipment. All forecasts of electricity consumption ultimately depend upon inferred or assumed relationships to describe the future behavior of these variables. This partitioning of the demand-forecasting problem is conceptually useful and will guide the discussion presented in this paper. However, it is also something of an oversimplification. Examined in more detail, the electricity fore-casting problem is exceedingly complex. The variables mentioned above are, in turn, found to depend upon more fundamental sets of demographic technological, resource, and policy variables. The demand projections developed by the major forecasting services are usually developed in terms of these underlying variables, which themselves must be independently forecast.

Jan 1, 1985

By S. J. Schatzel, K. M. Ajayi, E. N. Rubinstein, Z. Khademian

This study simulates the impact of a shale gas well casing breach near a longwall mine. Field studies are conducted to measure mining-induced permeability changes over the abutment pillar of a longwall mine, and a geomechanical model is developed in 3DEC, a three-dimensional numerical modeling code, to predict the aperture of fractures in the overburden at the study site. The predicted aperture values are used to determine mining-induced permeabilities, and the results are compared with the field measurements. These aperture values are provided as inputs into fracture flow code (FFC), which generates a stochastic discrete fracture network (DFN) model for the study site and predicts the potential shale gas flow to the mine. Results from 100 DFN realizations are statistically analyzed using the bootstrapping method to compensate for notable variation in fracture geometry. The results show a significant difference between the gas inflow for nearby panels due to increase in the induced permeability during mining of the second panel. The average gas flow to the mine was calculated as 4.72 × 10 m3/s (49 cfm) for a hypothetical breach at the Sewickley horizon during the first panel mining, 8.97 × 10 m3/s (19 cfm) for a hypothetical breach at the Uniontown horizon during the first panel mining, 2.16 × 10 m3/s (458 cfm) for a hypothetical breach at the Sewickley horizon during the second panel mining, and 8.07 × 10 m3/s (171 cfm) for a hypothetical breach at the Uniontown horizon during the second panel mining. Depending on the mine ventilation system, this could result in methane concentrations exceeding regulatory limits. Hence, these findings provide insights into the potential risk of an unconventional gas well casing breach near a longwall mine under shallow cover.

Feb 1, 2024

By Fabian Laumen, Sunny Schoone, Felix Leaman, ELISABETH CLAUSEN

The acoustic emission (AE) technology has a high potential for flow characterization in hydraulic transport processes. For instance, in deep-sea mining, there are applications where manganese nodules are transported from the bottom of the sea to the surface or a transport ship. Here, an AE-based flow characterization system plays an important role to avoid the transport of non-related objects. However, the structural materials for the components of this system must be carefully selected to ensure resistance against corrosion and a good AE signal transmission. Therefore, in this experimental study, we evaluated the AE attenuation behavior of four different materials that can be employed in marine environments due to their properties. The results were obtained using thin plates and they indicate which materials have the highest and lowest attenuations. Moreover, we provide insights regarding the different wave modes that propagate on the plates.

Mar 2, 2023

By M. Baumann

Operating and maintaining the heavy equipment used in open-pit mining operations is an ongoing challenge for mines. Typical operations employ a combination of shovels, wheel loaders, and haul trucks to excavate and transport the material for further processing. As this is the first point of contact for the material after blasting, it is often a bottleneck of all downstream processes, thus, equipment uptime and efficiency is crucial. Automated systems for bucket tooth monitoring, payload measurement, proximity detection, and rock fragmentation analysis will be examined. The impact of these systems on operation safety, efficiency, and reliability, in real-world scenarios will be investigated. The process of managing all the above fleet of equipment in a mine can be streamlined by connecting the equipment monitoring systems to a central server. Using the central server, the distribution of this information can be automated to ensure that the right people see the data in a timely manner, improving both proactive and reactive responses to threats to safety and productivity.

Feb 23, 2014

By Thomas S. Nye

Mineral exploration in the United States relies heavily on theoretical geologic concepts and indirect methods such as geophysics and geochemical prospecting, as there are few exposed areas of mineralization which have not already been explored at least once. In Mexico ore-grade samples can be cut at the surface on vein, replacement, and disseminated types of deposits in many areas. Here the problem is not in finding a mineralized area but in deciding which mineralized area can be explored and developed at the least risk and cost, and have the greatest profit potential, within the framework of Mexican mineral economics and government policies. Mexico's min¬eral industry is regulated through a system of permits for various phases of mineral exploitation, and by taxes. This regulation and its effects are not unlike those which may be expected in the United States if present legislative and administrative trends continue.

Jan 1, 1972

By W. L. Price

Recent publication of United States Bureau of Mines figures showed that the sand and gravel (3) industry is the largest single mining industry in the United States in term of yearly tonnage produced. The yearly production of over 500,000,000 tons per year now exceed bituminous coal production. This disclosure caught unawares many observers who have not been following closely the rapid-growth of this phase of mining. Along with this steady growth in production, the sand and gravel industry has gone through an accelerated and varied program of beneficiation in a period of the last ten years.

Jan 1, 1958

By G. Southam

Bacterial populations play an active role in mineral weathering in subsurface and near-surface environments e.g., supergene enrichment of Cu at Morenci, AZ. An in vitro bacterial biofilm model was used to examine the interaction between Sporosarcina ureae and ionic gold (which is toxic) or amino acid-gold complexes in gold mobility. The immobilization of ionic gold was between 80-90% for 1 week but as the available, cellular reactive sites became saturated immobilization decreased to 14% within 2 weeks. In the asparagine-gold system, gold immobilization occurred at a high rate (80-90%) throughout the experiment with limited toxicity towards Sporosarcina ureae.

Jan 1, 1999

By Garland R. Dever

Limestone resources for industrial, constructional, and agricultural uses occur on the surface and at minable depths in several areas along the Ohio River and its navigable tributaries in Kentucky. Operable thicknesses of high-calcium and high-carbonate limestones suitable for use in cement and lime production, steel manufacture, environmental-control measures, and other special uses are documented in Ordovician and Mississippian formations by analysis of 0.3-meter (foot-by-foot) samples. Active and potential mine and quarry sites afford access to water transportation and proximity to a number of industrial and metropolitan centers. Geologic factors affecting the distribution of deposits include the Cincinnati arch, regional dip into the Appalachian and Eastern Interior basins, complex faulting in and near the Western Kentucky fluorspar mining district, and late Paleozoic erosional unconformities in northeastern Kentucky.

Jan 1, 1977

By L. Wilfley, G. A. Calboreanu

"Wear resistant 25% Cr hard cast iron is a heterogeneous material containing 1,600 HV hard chromium carbides embedded into martensitic matrix. It is the most used cast alloy in wear operations of mining industry, chemical industry, fracking, etc. During the last decade the hard iron manufacturers increased wear resistance in the following ways: • Reduce / eliminate harmful retained austenite and chromium + carbon depleted areas especially within eutectic carbide cells. In Max5A the improved 25% Cr alloy brittle carbide eutectic cells are removed which increases toughness. • Delay delamination between chromium carbides and matrix particularly during sliding abrasion wear. Delamination commences at the weakest chromium carbide – matrix contact lines exposing chromium carbide to localized bending stresses which gradually chip carbides away. Once the chromium carbide base is removed accelerated wear degradation occurs. • Evenly randomize and avoid discontinuities in the chromium carbide network. When chromium carbides are perpendicularly positioned to the wear surface wear rate is minimized. On the contrary the highest wear rate takes place when 3D oriented chromium carbides are parallel with the wear surface. In this case chromium carbides cover top network discontinuities being just matrix supported which leads to rapid carbide cracking. The new hard iron discussed in this paper fulfils and exceeds the above requirements increasing the casting service life around 250% in various wear operations. Physical and mechanical properties of Max5A are compared with well manufactured Industry Standard 25% Cr hard iron. The paper presents practical accomplishments obtained in the USA, South America and India. INTRODUCTION The chemical composition of Max5A and Industry Standard 25% Cr are identical like specified by ASTM A532 Class III Type A requesting C = 2.0-3.3% and Cr = 23.0-30.0%. Manganese, silicon, nickel, molybdenum and copper contents are limited by maximum accepted quantities.[1] According to published data the eutectic chromium carbides chemical composition of 25% Cr hard iron is Cr = 54% and C = 8% which indicates strong depletion of chromium and carbon along chromium carbide - matrix interfaces. [2] The optimized Max5A microstructure has minimized retained austenite, is devoid of harmful carbide eutectic cells and has the most advantageous chromium carbide and secondary chromium carbide morphology. This favorable microstructure increases wear resistance, mechanical properties and corrosion resistance. The paper compares the Max5A microscopic features and mechanical – physical properties with similar properties of high quality Industry Standard 25% Cr."

Jan 1, 2017

By Yoginder P. Chugh

The control of soils has been found to be one of the highest priority factors influencing the return of reclaimed prime farmland to production. The compaction of soil is primarily a result of the movement of high ground pressure wheel scrapers and dozers over soils during the soils replacement and regarding process and occurs to a maximum depth of about 1.2 m (4 ft) The deleterious effects of soil compaction can be controlled by deep soil loosening to a depth of 1.2 m (4 ft). Most farm tillage equipment can only loosen soils to a maximum depth of 0.33 m (1.0 ft). Deeper soil loosening equipment, in the 0.33-1.2 m (1.0-4.0 ft) range is currently avail- able in the U.S. and abroad which may have potential for application on reclaimed prime farmland. This study has appraised such available equipment and the results indicate that a few manufacturers in the U.S., West Germany, and England market static and vibratory soil loosening equipment which have potential for deeper soil loosening of reclaimed prime farmland.

Jan 1, 1985