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By D. R. Tweeton

A modified push-pull field test and a computer model of cation exchange were developed to aid in evaluating cation exchange parameters prior to in situ mining. Reliable determination of these parameters is essential when modeling restoration of groundwater quality. The field test involves a much larger volume and much less disturbance to the ore sample than is feasible with laboratory measurements. This test can be performed in two or three weeks. It is relatively inexpensive, requiring one injection- production well and two or more wells for collecting samples of leach solution. The use of the model in interpreting test results is illustrated with field data from an in situ uranium mine. Much of the research was performed by the University of Texas at Austin, and was partially funded by the Bureau of Mines.

Jan 1, 1986

By Madan M. Singh

A new mining project can raise questions about what effect it will have on the community after it closes. Historically, little was done by communities to plan for and accommodate the changes in the economic infrastructure when a mine project is finished either after the ore runs out or if market conditions deteriorate and make it unprofitable. Projects that were underfunded were generally unable to withstand periodic market downturns. However, data in a recent study conducted by the Seidman Research Institute leads to the conclusion that, even when a mining project is terminated, there can be (and, in the specific case studied, is) a residual beneficial economic effect in the community, which lasts for a long period of time.

Jan 1, 2010

By Walter R. Hibbard

Precipitation in the northeastern United States, Florida, California and in many industrialized areas of the world is now more acidic (lower pH) than can be accounted for by natural causes. At the same time, the acidity of many lakes and streams in the northeastern United States has been measured and found to be similar to that of actual rain. These facts have led to conclusions that the two conditions are related. Coal burning utilities, 700 to 1000 miles upwind, have been accused of being the cause, leading to proposals for strict emission controls on the alleged offenders. The costs of these controls would place an estimated $10 to $15 billion capital burden on utility customers in about 15 states plus $2 to $6 billion annual operating costs. There appears to be no direct well-established scientific evidence that the accused are guilty but that the indictment is based largely on circumstantia1 evidence. This study examines the evidence, describes the situation and proposes what must be done to reduce the acid precipitation in an orderly cost beneficial manner. It is interesting to observe that studies by the different adversaries on the acid precipitation issue come to different conclusions largely because they do not read the same literature, but selectively develop evidence to support their own points of view, This study will try to review the issues impartially and reach a position of scholarly balance.

Jan 1, 1982

By Han Zhao, FENGLIANG WU, Tong Wang

Calibrating an entire mine ventilation network model from survey data has long been considered a challenging and sometimes impractical task. This paper proposes a solution to this issue with the development of a quadratic programming optimization model. The optimization model takes the minimum modification of input resistances as the objective function, uses the mesh pressure equations as equality constraints, and incorporates the lower limits of airway resistances as inequality constraints. A two-step method is developed to solve the model, which includes finding an initial feasible solution and iteratively solving the final solution using the active set method. A computer program has been developed to implement the optimization model. To demonstrate its practicality, a study case using a 35-branch ventilation network is presented, which indicates that the solution process converges after only 57 iterations, a significant improvement over the times of trial and error, which could reach 3.4 × 1010 for the worst-case scenario. Additionally, it is shown that considering only the equality constraints results in negative resistances, while incorporating the lower limits of resistance ensures that the corrected resistances are within a reasonable range. Using the resistance corrected by the optimal model to simulate the ventilation system via traditional methods generates quantities and fan pressures that perfectly match the measured values, eliminating the tedious process of manually adjusting airway resistances repeatedly.

Jan 13, 2024

By Fathi Habashi

CLAYS CONTAIN the mineral kaolinite, a hydrated aluminum silicate. It is an important potential raw material for aluminum, especially for those countries possessing no bauxite deposits. Therefore, there is no surprise to find a large volume of research done for the recovery of aluminum from clays. Kaolinite (Al203?2 SiO2?H20) contains 39.8% A1203; 46.3 % SiO2, and 12.9 % H2O. The analysis of a good-quality dried clay of an Eastern Canadian siliceous shale is shown in Table 8-1.

Jan 1, 1970

By R. Duckett, D. Salisbury, R. Dorey

The Kennecott Ridgeway Mine in South Carolina is scheduled to complete mining and ore processing in the last quarter of 1999. Tailings are disposed in a 300 acre, lined tailings impoundment. To facilitate closure and reclamation, modification of the tailings impoundment operation has been adopted. Mining involved the sequenced development of two open pits. In 1996 mining of the South Pit was completed and backfilling of the pit with waste rock from the North Pit was initiated and will continue until mining ceases. Both pits will be reclaimed as fresh water lakes. This paper presents the physical, geochemical and hydrogeochemical evaluation of the operational and post operational management of the project. Comparison of the operational monitoring data against predicted performance are reviewed.

Jan 1, 1999

By C. D. Secrest

Visiting Spring Canyon, a historic coal mining district near Helper, Utah, I was impressed by the great accomplishments that had taken place there. A tour book of the region tells of a period that began in the early 1900's, when the land was still very much the Old West, when settlers lived out their lives in coal company towns and produced a resource that was to build a nation (Cunningham, F., 1990). Between 1912 and the early 1970's, 11 mines had come and gone in that narrow canyon less than 15 kilometers long. Spring Canyon is a historic district now, but I could not dwell too long on the richness of its history. I was there to look for evidence of PCBs.

Jan 1, 1993

By Sheldon P. Wimpfen

Back in 1970 Congress passed the National Mining and Minerals policy Act, which had as one of its basic tenets to rely on a strong and stable private minerals industry for the development and production of our mineral resources. Since then, a substantial amount of legislation has been introduced that impacts on the minerals industry. Although most of the bills proposed are not passed into law, each bill affecting minerals and mining is given careful review by the Bureau of Mines. Comment is forwarded with the object of being helpful to legislators by providing our assessment of the probable impact of each bill proposed along with suggestions to improve them. Actually few bills introduced become law. For example, in the 93rd Congress 4,260 bills were introduced in the Senate and 17,690 in the House. In the final accounting there were passed 123 private laws and 649 public, 3 percent of the bills introduced. There would be little merit here in attempting to analyze each mineral-related bill that was proposed. Many are similar and aim at making a certain aspect of our minerals activity fit needs. So, to simplify the task the many bills have been grouped by subjects. Slide 1 shows the principal topics and the number of related bills introduced. Putting it altogether, there are 26 principal subjects and almost 200 bills. And these numbers are probably off somewhat, as this accounting was made early in December.

Jan 1, 1976

By Hongsheng He, Xiaofang Lv, Jianfeng Wang

This paper provided an overview of characteristics of limonite ores as well as their influence on sintering performance. Evaluation experiments focusing on basic characteristics, granulation characteristics, and high temperature sintering characteristics had been conducted by using two types of limonite ores, then the principles of high effective utilization technology of limonite ores were discussed, and the sintering pot tests were conducted. Limonite ores possessed low total iron content, high combined water content, high SiO2 content, large average particle size, low adhering particles proportion, high porosity, high water absorption rate, short water absorbing time, poor granulation ability, high melt formation ability, low melt fluidity ability, low melt penetration ability, high melt absorption ability, low bonding phase strength, and high forming ability of SFCA. By taking the technical measures of ore-proportioning optimization, increasing the proportion of burntlime and segmentation granulation, the usage of limonite ores could reach 50% in sintering.

Aug 27, 2021

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 Y. Zhang, M. Yekich, C. Zhou, C. Jobes, J. Galanko, D. Tuchman, J. Srednicki, J. Carr

The continuous personal dust monitor (CPDM) is an essential instrument for working in hazardous environments, is used to monitor real-time coal dust exposure, and is mandated by the Mine Safety and Health Administration (MSHA) for underground coal mines. Researchers from the National Institute for Occupational Safety and Health (NIOSH) found that it is possible for electromagnetic interference (EMI) between a CPDM and a proximity detection system (PDS) to occur. Various approaches have been taken by researchers and manufacturers to address this EMI issue. Administrative controls were recommended to keep the CPDM six inches away from the wearable PDS device. Shielding pouches were made to contain the electromagnetic (EM) emission from the CPDM. Metal shielding was added to major EM emitting components. EMI filtering with large capacitors was introduced to mitigate EMI. Most recently, a novel magnetic-field-cancellation-based approach was developed and achieved remarkable results. In this paper, we provide a comparison between these approaches. The pros and cons of each approach are presented and discussed, so that mining device manufacturers and operators can best evaluate the technology and controls that improve the health and safety of mine workers.

Feb 1, 2023

By A. M. Anthony, A. Y. Atta, S. S. Magaji, U. Abubakar-Zaria

There are two major gold recovery methods: the hydrometallurgical technique, which employs cyanide solutions, and amalgamation method, which involves mercury (Hg). These methods present considerable health, safety, and environmental concerns. Past applications of alpha-cyclodextrin (α-CD) on gold scraps show that α-CD is not only inexpensive, but is also environmentally friendly. This research work used α-CD to recover gold from gold ores instead of gold scraps. The gold ore was sourced from Shanono gold deposit site Kano State,Nigeria. The gold ore was characterized by fire assay (FA) for the precious metal. The concentrate was digested with aqua regia (AR) for 24 h. Modified AR, where hydrochloric acid was replaced with hydrobromic acid, was used for the gold digestion due to the good match in molecular recognition between gold bromide ion (AuBr)− and α- CD in a second sphere coordination complex. The digestate was characterized using atomic absorption spectroscopy (AAS). Gold recovery using this technique is pH sensitive, and five pH values (2.0, 3.6, 4.0, 5.4, and 6.0) were investigated. FA analysis showed the Shanono gold ore deposit contains an average of 4.71 ppm of gold, AAS analysis showed highest gold recovery of 69% at pH 4.0, which is lower than recoveries from the metal scraps. This could be due to the presence of other gangue minerals closely associated with the ore. However, gold recovery using α-CD on Shanono gold ore has shown to have a higher yield of 69% compared to 35.5% yield obtainable by Artisan Small Scale Miners using mercury.

May 5, 2020

By MUSTAFA ERKAYAOGLU, ENVER YILMAZ

Coal mining is likely to sustain its critical role as energy requirements are increasing. While surface mining exploits coal seams near the surface, underground mining techniques are crucial for extracting deep coal reserves. Longwall mining is one of the most common methods used in underground coal mining operations. This paper introduces a data-based framework — including data collection, data analysis and the interpretation of operational data — for understanding the system efficiency of a longwall shearer. Operational performance is evaluated by the time between arrivals (TBA) and duration of the shearer stoppages, shearer drums’ reversal time, cutting speed and flit speed on daily production in a longwall top coal caving (LTCC) mine. A discrete event simulation model is developed to represent the bidirectional cutting sequence of a longwall shearer.

By Xiaozhen Song, Ashish Ranjan Kumar, Shimin Liu

To investigate the influence of boreholes, fans, and curtains for large opening underground mines (LOUM), we conducted a field survey for LOUM with the survey data serving as the numerical modeling inputs using computational fluid dynamics (CFD) models. Five different CFD modeling results were obtained with different borehole, box fan, and curtain setting conditions. The results indicate that most air quantity directly escapes through outlet 1 after coming into the inlet, causing a huge loss of airflow; volumetric air exchange index (VAEI) and minimum hours of fully exchanging the air (MHFEA) measure air exchange efficiency, with zone 2 of case 5 having the highest VAEI; The borehole minimally affects zones 2, 3, and 4, but drastically alters airflow direction in zone 1; The box fan enhances airflow to zone 2, improving ventilation efficiency and increasing VAEI; Curtains have little effect on distant working faces but influence airflow near inlets and outlets. This study provides a foundation for future research on the influence of boreholes, fans, and curtains, as well as optimizing their placement and effectiveness in face ventilation.

Feb 22, 2026

By Manoj Khandelwal, Jian Zhou, Yingui Qiu, Peixi Yang, Pingan Peng

Rockburst prediction is crucial in deep hard rock mines and tunnels to make safer working conditions. Due to the complex interaction of many factors involved in rockburst prediction, such as multi-variable and multi-interference factors, three hybrid support vector machine (SVM) models optimized by particle swarm optimization (PSO), Harris hawk optimization (HHO), and moth flame optimization (MFO) are proposed to predict rockburst hazard level (RHL). The RHL is determined according to four kinds of microseismic characteristic parameters including angular frequency ratio, total energy, apparent stress, and convexity radius. Then, six types of microseismic characteristic parameters are taken as input variables in 343 sets of data, including angular frequency ratio and total energy, etc.. And the RHL is taken as the output target of rockburst prediction. The classification performance of PSO-SVM, HHO-SVM, and MFO-SVM hybrid models is evaluated by accuracy (ACC), precision (PRE), and kappa coefficient. Findings reveal that the MFO-SVM model performs best in terms of accuracy, with ACC, PRE, and kappa coefficients reaching 0.9559, 0.9063, and 0.9094 respectively, while PSO-SVM and HHO-SVM have similar performances. However, the PSO-SVM, HHO-SVM, and MFO-SVM all perform better than the unoptimized SVM model. This confirms that the three optimization algorithms significantly enhance the rockburst prediction capacity of the SVM model to help mine practitioners apply machine learning methods to rockburst prediction problems appropriately.

Feb 3, 2023

By G. D. Hood, C. E. Jordan

The US Bureau of Mines investigated rapid froth flotation through more efficient bubble-particle collisions that improved the overall flotation kinetics. An in-line static mixer efficiently mixed the bubbles, water and ore, selectively attaching these bubbles to the hydrophobic mineral's surface. As the mixture entered the flotation chamber, the hydrophobic mineral was already attached to the bubbles and was quickly floated away from the remaining ore pulp. The rapid flotation system was evaluated for beneficiation with a western porphyry copper ore containing 0.67% copper and with a phosphate-bearing amine flotation tailings sample containing 9.5% P2O5 in a quartz matrix. Over 88% of the copper was recovered from the ore in a rougher concentrate containing 5.9% copper at a rate seven times, faster than conventional flotation. Sixty percent of the quartz in the phosphate-bearing sample was floated at a rate four times faster than conventional flotation. The unfloated product retained 80% of the phosphate in a 16.9% P2O5 concentrate.

Jan 1, 1994

By D. Morgan Warren, David Hanson, Alice Alex, Tom Meuzelaar, Heather Lawson, Sam J. S. Wright

Dynamic coal failure events remain a safety concern in underground coal mining due to their sudden nature and high fatality rate. Previous research utilized Principal Component Analysis on field samples revealing strong empirical correlations between positive failure history and low sulfur content (S) and high volatile matter (VM). Further studies indicated that bumping coals tend to be less mature and less well-cleated than non-failure coals. However, these in situ studies faced the challenge of distinguishing intrinsic coal properties from external geological and stress-related influences. This study augments previous findings through laboratory experimental testing of coal samples that included unconfined compressive strength, chemical composition analysis, and qualitative observations on cleating, combined with compositional data analysis and machine learning techniques, to isolate and understand coal’s inherent bursting capacity. These results further confirmed the relationship between coal chemistry and failure classification.

Feb 22, 2026

By J. Christophe Niyonzima, Ekata Emmanuel Edo, Sayaf Mustafa, Liqun Luo

Iron and manganese both are important ferrous metals, and they usually need to be extracted separately for better usage. Ferromanganese ore from the Yunnan Province of China was investigated by subjecting it to reduction roasting, leaching, magnetic separation, hydrometallurgical separation process, X-ray diffraction (XRD), electron probe micro-analysis (EPMA) and scanning electron microscopy/energy-dispersive spectroscopy (SEM-EDS). It is noted that the ferromanganese ore contains valuable components or elements of 21.41 wt%Fe2O3 and 19.88 wt%MnO, which are 14.99% and 15.40% of the total of Fe and Mn, respectively, with a large amount of impurities comprising 33.00 wt% SiO2, 9.81%wt%Al2O3, etc. After roasting, microscopic examination showed the presence of haematite, magnetite, pyrolusite, psilomelane, hollandite, marcasite, pyrite, limonite, braunite and manganite, while XRD analysis showed that the magnetite content increases with the increase in roasting temperature, reflecting the increase in conversion of haematite to magnetite. Based on EPMAand SEM-EDS analysis, it was shown that the haematite and magnetite interface were the main Fe-bearing minerals; however, the dissemination of the two minerals, that is, haematite andmagnetite with the coexistence of Fe- and Mn-bearing minerals, will result in difficulty in effective separation of Fe and Mn. The effective roasting temperature and roasting time were 800 °C and 60 min, respectively, to avoid the formation of a composite oxide of MnxFe3-xO4 beyond 800 °C. The Fe recovery via roasting and magnetic separation only was 66.56%, whereas a combination of magnetic separation which ensued after the leaching process showed a recovery of 80.08% and 59.95% of Fe and Mn, respectively.

Mar 26, 2021

By Immo H. Redeker

The Kings Mountain area of North Carolina is the lithium pegmatite center of the U.S., if not of the whole world. We have two spodumene and by-product mineral producing companies, Lithium Corp. of America, and Foote Mineral Company. We also have Kings Mountain Mica and Kings Mountain Silica Companies producing mica. feldspar, quartz and clay from weathered pegmatites in that area. Figure 1 gives the location of the spodumene pegmatite area in North Carolina. The two spodumene producers mine typical pegmatite ore in open pits after removing amphibolite or mica schist overburden which is sold to aggregate producers. The ore reserves are discussed elsewhere in this session. They are in the order of plus 50 million tons but not unlimited. 1.2 The major minerals found and concentrated from the North Carolina spodumene pegmatite ores are tabulated on Table 1.

Jan 1, 1977

By W. R. Reed, G. W. Luxbacher

Mine worker exposure to respirable coal dust and silica dust can result in coal workers’ pneumoconiosis and silicosis which are occupational respiratory diseases that have no cure and are ultimately fatal. In 2021 the Mine Safety and Health Administration reported just over 11,000 operating metal/nonmetal mines with the potential for silica dust exposure for just under 200,000 miners. The National Institute for Occupational Safety and Health (NIOSH) conducts respirable coal and silica dust research associated with mining through its Office of Mine Safety and Health Research. NIOSH respirable coal and silica dust research began under the U.S. Bureau of Mines (USBM), which initially examined silica dust, progressing to include coal dust, with a stronger focus after 1969 with the passage of the Federal Coal Mine Health and Safety Act. A review of extramural research to develop real-time respirable silica dust monitor is presented along with a brief history of silica dust regulation.

Feb 1, 2024