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By E. R. Palowitch

On February 5, 1973, Eastern Associated Coal Corp began shortwall mining in their Federal No. 1 Mine, thus marking the first attempt in the United States at modern shortwall mining, i.e., using a continuous miner to extract coal open-ended from pillars 100 to 200 feet wide, under the protection of a self¬-advancing roof support system (1)1/. Since then, four additional shortwall faces have been operated. While the number of face-years of shortwall experience in the United States is limited, this experience has been anything but uniform. Differences in operator motivation, coalbed parameters, geologic conditions, panel dimensions, and face equipment all have contributed to a wealth of knowledge which can provide guidance for the design of future shortwalls. The purpose of this paper is to review the history of shortwall mining in the United States and to assess its value to the U.S. coal industry in terms of the health and safety of the miner, the percentage of coal recovered, coal production, worker productivity, and relative cost performance.

Jan 1, 1976

By J. Kretschmann, H. Mischo, O. Drusche, S. Krause

Mining is and will be inevitable in spite of the increasing implementation of circular strategies. The energy transition and population growth will boost the demand for critical raw materials. It is the opportunity for miners to reinvent their business models. Generating attractive new business cases with sustainability-oriented innovations meets investor and stakeholder expectations from the beginning. This contribution guides managers on their pathway towards sustainable success. Contextual sustainable business model patterns will be presented that can be adjusted individually, regardless of actor’s size. It will also point out, how sustainable value creation can be measured on business model level.

Feb 1, 2023

By Alain S. Kivava, Olawale K. Aromolaran, Charles Nzolang, Anthony T. Bolarinwa, Georges M. Kasay

Rare earth elements (REEs) are crucial in high-tech and green technologies. The Democratic Republic of Congo (DRC), rich in mineral resources, shows potential for REE deposits in carbonatites, pegmatites, and placers. This paper reviews global REE resources, highlights potential REE targets in Africa, and emphasizes the need for further research and exploration in the DRC to unlock its REE potential.

Feb 4, 2022

By Knut H. Hubert

The GRATE-KILN System plant at Svappavaara, Sweden, was constructed for LKAB by Allis-Chalmers under a turnkey contract and commissioned in 1969. The plant was designed to produce iron ore pellets from magnetite concentrate at 6100 mtpd using imported fuel oil. It represented the state of the art for plants of its type at the time. Fuel rated capacity was attained within one week of start-up. Product quality, power usage, fuel consumption and machine wear were within warranty limits during sustained production thereafter. As operator skills improved and gas handling system reserve capability was utilized, the plant frequently produced acceptable product at up to 115% of design capacity. During the period 1969 to 1976, market demands increased for high-quality pellets while energy costs rose steadily. At the same time, important advances in the design of GRATE-KILN Systems were being made in other plants constructed by Allis-Chalmers.

Jan 1, 1980

By Winfield G. Wright, Philip L. Verplanck, Philip L. Hageman, Douglas B. Yager, Dana J. Bove, M. Alisa Mast

Geological, hydrological, and geochemical information synthesized in a Geographical Information System (GIS) for water and rock surrounding South and Middle Forks of Mineral Creek, northwest of Silverton Colorado, was analyzed to distinguish between the natural and the mining-related sources of metals to dace waters in the watershed An important natural source of metals to surface water emanates from a porphyry molybdenum deposit south and upslope from the Middle Fork of Mineral Creek. Interaction of surface and ground water with fractured, altered rocks and permeable, Quatemay-age surficial deposits produces downstream water quality that does not meet current State of Colorado water quality standards for metals and pH. GIS site characterization and three-dimensional modeling distinguish surficial deposits as volumetrically substantial, significant sources of naturally occurring metals that strongly influence water quality and complicate ongoing mine-site mitigation efforts. Our findings indicate that regional hydrologic and geologic information needs to be evaluated before realistic water quality guidelines are established and mitigation recommendations are confidently implemented.

Jan 1, 2000

The National Mining Hall of Fame and Museum (NMHF&M) will celebrate its 25th anniversary on Sept. 22, 2012 when the 2012 class is inducted during a special ceremony in Las Vegas, NV in conjunction with MINExpo 2012. The NMHF&M will induct four men representing the equipment manufacturing, minerals exploration, copper and coal sectors of the mining industry. The diverse cross-section of mining industry giants joining the hall of fame include Glen A. Barton, J. David Lowell, Samuel Newhouse and John Cleveland Osgood. They will join 214 other mining industry pioneers when they are formally inducted into the National Mining Hall of Fame at the 25th Silver Anniversary Induction Banquet & Ceremony. These men were selected for being visionaries, leaders and ambassadors within their own sectors and across the industry at large.

Jan 1, 2013

By Jamal Rostami

With the recent technological advances; Tunnel Boring Machines (TBM) have become a viable economic alternative to drill and blast in hard rock excavation. These machines are finding increasing use in underground mine development due to the potential benefits they offer. The successful application of TBM technology to mining depends on the selection of the most suitable equipment and cutting tools for the rock and ground conditions to be encountered. In addition to required testing and geotechnical investigations, cutterhead design optimization is an integral part of the machine selection to assure a successful application of the machines in a specific project. This paper presents and discusses the back-ground of TBM application in a mining environment and the lessons learned, the process of conducting site investigation and the necessary laboratory testing together with machine selection and performance estimation for TBM use III mine development.

Jan 1, 1997

By Nick Hasenack

In the pelletizing plant of Hoogovens, Estel BV, a varying mixture of hematites and magnetites is used for the production of acid and (occasionally) fluxed pellets. Optimum results regarding productivity, quality and process control are obtained with mixtures containing 30-40 % magnetites. A decrease of the magnetite ratio or an increase of the basicity has a great influence on both productivity and heat and power consumption. Tests have been carried out to find the extent to which magnetite can be replaced by b.f. dust, mill-scale and coke breeze. Pilot plant tests show that about 80-100 % of the production loss due to a decrease in magnetite content or to the increase in basicity can be regained without damage to the quality by adding coke breeze. The amount of coke breeze should be limited tot 1,5 %; if this percen¬tage is chosen higher, the quality of the pellets deteriorates rapidly. The amount of coke breeze to be added should be about 30 % above the theoretical value, based on heat balance considerations. The results achieved by incorporating b.f. dust and mill-scale into the pelletmix were also encouraging, but as some types of mill-scale are very difficult to grind and the supply of b.f. dust is limited, the research has not been carried out extensively in this field. The pilot plant tests on replacement of magnetite by coke breeze have been followed by industrial tests, during which the breeze was added to the ore feed before the dry-grinding system.

Jan 1, 1977

By R. K. Steinhorst

Multivariate cluster analysis, MANOVA, canonical analysis, and discriminant analysis of hydrochemistry data were used to investigate the directions of ground water movement in basalts in the vicinity of the Hanford Reservation, Washington. The statistical analyses indicate that the hydrochemistry of the ground waters in these basalt formations is distinctly different on each side of the Columbia River. This suggests that the river is a ground water divide or that the river is roughly coincident with a hydrogeologic barrier boundary. The statistical procedures used in this study constitute a quantitative means for differentiating ground waters according to hydrochemistry.

Jan 1, 1990

By G. L. Mowrey

In addition to developing various types of coal interface detection systems, the U.S. Bureau of Mines is actively involved in developing a coal rib thickness monitoring system for high wall mining applications. One particular system that appears to show promise uses a ground-penetrating radar system to detect the coal-air boundaries of coal ribs. Based on preliminary laboratory and field tests, results indicate that this method can be applied successfully in highwall mines to maintain a constant rib thickness. The coal seam should be relatively clean in the vicinity of the antenna (e.g., have minimal partings or dirt bands) for best results.

Jan 1, 1995

By P. M. Soupios

An integrated suite of environmental methods was used to characterize the hydrogeological, geological and tectonic regimes of the study area, to determine the geometry of the landfill (depth and spatial extent of electrically conductive anomalies), to define the anisotropy caused by bedrock fabric fractures and to locate potential zones of electrically conductive contamination. The study area which covers an area of about 0.08 Km2 is a municipal solid waste site (MSW), located 20Km West of Herakleion in the central part of Crete (S. Greece). The landfill is located in a northwest oriented valley with highlands to the northeast and southwest. The combination of geophysical methods and chemical analysis are commonly implemented for characterization and management of land-fills. At the particular site, geophysical methods were focused on studying the electrical insolating properties of the materials, electrical con-ducting properties of fluids (leachates) and electromagnetic properties of the disturbed regolith materials in the burial zones. Three different types of geophysical surveys were performed: 1) 2D electrical tomography (ERT), 2) electro-magnetic measurements using very low frequencies (VLF) and 3) electromagnetic conductivity (EM31). Furthermore, in order to calibrate the geophysical methods dielectric spectrometry measurements are conducted. To evaluate the environmental degradation of the area, soil and liquids samples were collected.

Jan 1, 2005

By Rahul Singh, Sunil Kumar, Erich Dohm, Maoming Fan

The rapid increase of P2O5 use for food, biofuels, and LiFePO4 batteries etc. accelerates the depletion rate of phosphate reserves. In the phosphate industry, a significant amount of ultrafine phosphate has been discarded as slime tailing due to processing difficulties. The major problems associated with ultrafine particle flotation are low probability of bubble-particle collision and adhesion, and high probability of unwanted gangue particles entrainment. This paper investigates the enhanced ultrafine phosphate particle flotation probability by Eriez’ CavTube generated fine/ ultrafine bubbles and the improved flotation selectivity by wash water etc. Ultrafine phosphates with various gangue minerals of quartz/muscovite, calcite/dolomite, and iron/ silica were studied. Microscopic observations show that the entrained ultrafine gangue minerals can be minimized by using wash water in column flotation. A three-factor threelevel central composite experimental design was conducted for ultrafine phosphate flotation. For comparison, both benchtop mechanical cell and laboratory column flotation tests were performed at their optimal respective flotation conditions. Using Eriez CavTube column flotation technology for Industries Chimiques du Senegal (ICS) ultrafine slime tailings, a concentrate grade of 36.0% P2O5, was achieved at 89.4% P2O5 recovery. Improved flotation performance was achieved using column flotation as compared to benchtop mechanical cell flotation. The benefits of Eriez’ column flotation technology realized from this study include the high P2O5 grade and recovery.

Feb 1, 2024

By R. Mensah-Biney

The aqueous biphase separation process (ABS) has been used to separate ultrafine industrial minerals. The partition behavior of TiO2, Al2O3, Fe2O3 and kaolin was not pH dependent. The partition behavior of SiO2 was, however, pH dependent. The partition coefficient of kaolin in PEG 3400/ Na2CO3 biphase system was = 150 and that of the silica in the same system was = 0.02, resulting in a separation factor of = 8500 between kaolin and silica. The aqueous biphase separation system was used to separate free silica from kaolin in a raw clay sample from Mexico. The partition behavior of mica, feldspar and clay from North Carolina was also evaluated.

Jan 1, 1999

By T. Gelpe

A digital simulator of classification and grinding circuits is used to evaluate the performances of various flowsheets. For a given flowsheet configuration, unit processes dimensions and operating conditions, the simulator calculates the steady-state values of the process variables. A supervisory algorithm is implemented in the simulator to determine the conditions which meet the required criterion on operation, tonnage and product quality. Calculation illustrations are proposed for the design of wet and dry grinding circuits. The performances of various arrangements of cement clinker and sulphide ore grinding flowsheets are evaluated and discussed.

Jan 1, 1983

By Alireza Ayoubian, Richard Finno

The network of freight tunnels in Chicago consists of about 62 miles of horseshoeshaped tunnels constructed typically less than 50 feet below ground surface. These tunnels serve as repositories of much infrastructure and should remain serviceable. The tunnels are often impacted by adjacent excavations and the question arises as to the existing state of stress in the final liner. This paper discusses construction of these tunnels and presents the results of finite element analyses which were used to obtain ranges for axial forces and bending moments that have developed in the final liner of the freight tunnels since their construction.

Jun 13, 2023

By Cancelli Paolo, Bragonzi Gianluca, Pelizza Sebastiano

"In May 2015 the New Monte Bianco aerial cableway, operating on the Italian side, have been completed. It connects the lower station in Pontal d’Entreves (1300 metres above sea level (m a.s.l.)) with the intermediate station at Pavillon de Mont Frety (2160 m a.s.l.) and with the top station at Helbronner Peak (3460 m a.s.l.). A new underground link between Helbronner Peak and New Torino Refuge has also been built. The link is divided into two different sections: the first one, a 70 meters deep vertical pit created using the “Raise Boring”, descends underground from Helbronner Peak station; the second section, a 160 meters long sub horizontal tunnel, emerges at Torino Refuge. After a first introduction focused on the general layout of the project, the paper will present the geomechanical survey aimed to evaluate the effect of permafrost on the stability of intensely fractured granitic mass. Finally, it will describe the relevant issues related to the highest construction yard in Europe (3400 m a.s.l.): difficult conditions such as extremely cold and windy weather and restricted spaces. INTRODUCTION The new cable way connects the lower station in Pontal d’Entreves (1300 m a.s.l.), close to Courmayeur, with the top station at Helbronner Peak (3462 m a.s.l.) and its territory, as well as links with France and, through the French territory, with the town of Chamonix (1000 m a.s.l.). The overall layout is divided into two sections (as shown in Figure 1): the first section, “Pontal d’Entreves – Mont Frety”, has a length of 1700m, elevation differential of 886m, a capacity of 800 persons/hour and cable cars for 80 passengers; the second one, “Mont Frety – Punta Helbronner”, has a length of 2630m, elevation differential of 1276m, a capacity of 600 persons/hour, and cable cars for 75 passengers. The new system is designed for fully rotating cable cars moving at a constant rate of 9.0 m/s. The track requires constructing special cables supports, three for the first section and two for the second one."

Jan 1, 2016

By Morgan M. Sears, Mark Morris, Joseph Bright

In an effort to advance the science underlying modern coal pillar stability analysis, researchers at the National Institute for Occupational Safety and Health are currently involved in research aimed at better understanding the impact of an in-seam rock parting on the strength of coal pillars. The purpose of this study is to determine a suitable virtual mining height that could be applied using current pillar stability analysis tools. To accomplish this, the boundary element model LaModel was used to back analyze data collected on pillar performance in a room-and-pillar panel at the Maple Eagle Mine located in Southern West Virginia. In a previous work, data collected from borehole pressure cells (BPCs) and extensometers were taken from three instrumentation sites. Data collected from the back bleeders were used to measure the rear abutment stresses, and data collected from two instrumentation sites in the wraparound bleeder were used to measure the front and side abutment stresses as well as the peak strength and performance of the slabbed leave pillar. The utilization of two nearly identical instrumentation sites in the wrap-around bleeder provided much needed repeatability of the obtained measurements. In this study, the data collected from BPCs at the three instrumentation sites was calibrated to match the Bieniawski pillar stress gradient. To model the measured pillar behavior, the LaModel program was selected due to its capability of being directly comparable to the Analysis of Retreat Mining Pillar Stability (ARMPS) and Analysis of Coal Pillar Stability (ACPS) programs. The model was then calibrated to match the measured abutment extent and abutment stress. Finally, the model was validated by reducing the modeled mining height until the yielding of the slabbed leave pillars in the model matched what was measured in the field. The final calibrated mining heights show that a reduction of the shale parting thickness, not including any clay layers, of 52% is applicable. This research study provides the first known measurement of the ARMPS/ACPS “50% Rule” and its applicability to this panel of the Maple Eagle Mine. This finding provides a proof of concept and could have significant implications for future research.

Feb 1, 2024

By A. Nieto

This article is a review of previous discussions about underground mining method selection and classification with the purpose to clearly define and classify the two groups of variables (indicators) involved in the mining selection process: key deposit indicators (KDIs) and key mining method indicators (KMIs). This paper provides a simple and clear approach for the classification and selection of a feasible underground mining method based on a predetermined set of favorable deposit characteristics, which are defined as key deposit indictors (KDIs). This article also gives a summary of the key advantages and disadvantages associated with every underground mining method based on their key mining indicators (KMIs). The selection method given in this paper is based on defining field KDIs and comparing them to the KDIs that are favorable to every considered mining method. By cross validating a matrix of favorable KDIs, the paper presents a simple approach to rank several underground mining methods using a scale from favorable to less favorable accordingly to the ore deposit characteristics (KDIs). KMIs are used to further complement KDI rankings by analyzing every method’s KMI performance based on the expected productivity of the mining operation being considered. To further assist the reader through the selection process, this paper gives basic sketches representing each of the primary underground mining methods discussed in this paper. Each method is given using the same 3D isometric view as spatial reference to assist the reader with visual interpretation and comparison between methods.

Jan 1, 2010

By Dafydd Chandler, Milissa Hirst, Charles Hurst, Gary Snyder, Leszek Glodkowski

The Delaware County Regional Water Quality Control Authority (DELCORA) will be adding tunnel infrastructure to its wastewater conveyance system. This program involves the construction of a conveyance/storage tunnel and related facilities. The proposed 12- foot to 14-foot (±) finished diameter, TBM mined deep rock tunnel spans over 8.5 miles and lies approximately 80 ft-120 ft below the surface. The system is connected to the surface by at least five vertical online shafts and one offline shaft with associated 800ft long adit. This paper provides project details including data on the geologic conditions in which the tunnel will be constructed.

Dec 1, 2022

By M. L. Harris, J. Organiscak, S. Klima, I. E. Perera

"The Pittsburgh Mining Research Division of the U.S. National Institute for Occupational Safety and Health (NIOSH) conducted underground evaluations in an attempt to quantify respirable rock dust generation when using untreated rock dust and rock dust treated with an anticaking additive. Using personal dust monitors, these evaluations measured respirable rock dust levels arising from a flinger-type application of rock dust on rib and roof surfaces. Rock dust with a majority of the respirable component removed was also applied in NIOSH’s Bruceton Experimental Mine using a bantam duster. The respirable dust measurements obtained downwind from both of these tests are presented and discussed. This testing did not measure miners’ exposure to respirable coal mine dust under acceptable mining practices, but indicates the need for effective continuous administrative controls to be exercised when rock dusting to minimize the measured amount of rock dust in the sampling device IntroductionTwo recent regulations have modified operators’ rock dusting schedules in order to meet compliance standards. First, the 80 percent incombustible requirement in intake entries has increased both on-section and out by the- section rock dusting. Secondly, the recent change to the respirable dust regulation has increased the number of respirable dust samples taken per sampling cycle. Previously, when only five samples were needed bimonthly, rock dusting could be scheduled to not interfere with the respirable dust sampling schedule.The significant number of samples now required under new regulations, combined with the need to maintain 80 percent total incombustible content in active mining areas, require the schedules for respirable dust sampling and rock dusting to overlap. Although rock dust is considered a nuisance dust in relation to U.S. Mine Safety and Health Administration (MSHA) sampling, these overlapping schedules raise concerns about the amount of rock dust that potentially is included in the sample. Additionally, the respirable dust maximum was lowered from 2.0 mg/m3 to 1.5 mg/m3 effective Aug. 1, 2016, increasing concern that rock dust contamination may be an issue (MSHA, 2016). Currently, the acceptable practice is to apply administrative controls such as keeping the miners upwind during rock dust application, or to schedule rock dusting during a maintenance shift when the number of miners present is lower."

Jan 5, 2017