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By Stanisław Prusek, CHONG WEI, Huawei Xu, Jun Wang, Andrzej Walentek, Artur Dyczko, Derek B. Apel

The excavation-induced stresses transferred from the panels or pillars in upper coal seams play a key role in the occurrence of rockbursts in driving roadways during close-distance coal seam mining, which has become a common problem and threat to many underground mines. The authors established a 3D finite-difference numerical model via FLAC3D software using the closedistance coal seam mining conditions in the Zofiówka Mine as a case example to reveal the rockburst mechanism in such conditions. The excavation-induced vertical stresses are analyzed, which provides a basis to build a conceptual model to explain the possible source mechanism of the rockburst under such conditions. Nine typical rockburst indicators considering different contributing factors are then selected as the evaluation criteria to assess rockburst potential in the study site. The results suggest that the superposition of multiple excavation-induced stresses of the main drift and tailgate provides an environment for stress concentration and energy accumulation. The side abutment stress induced by mining in the upper coal seam has a “strengthening” effect to the rockburst occurrence. The great deviatoric stress induced by complex excavating situations is another important exterior cause. A strict calibration procedure should be implemented before using indicators to predict rockburst potential. A methodology was proposed to estimate the location and magnitude of rockbursts combined with numerical modeling, laboratory tests, and feedbacks from the field. The study could provide some references and guidelines for preventing and mitigating rockbursts in underground mines under similar engineering conditions.

Aug 26, 2021

By D. R. Tesarik, T. C. Trancynger, W. G. Pariseau

The Davis detector cavern was excavated on the 4850 Level of the former Homestake Mine in the mid- 1960s to house a novel neutrino detector developed by Nobel Prize winner Dr. R. Davis. The original cavern was about 9.1 x 16.8 x 9.7 m high, excavated in a Precambrian amphibolite known as the Yates unit and enlarged in 2010. In 2009, the National Science Foundation selected the site for development as a national Deep Underground Science and Engineering Laboratory (DUSEL). This retrospective rock mechanics study of the Davis cavern is intended to inform design of the much larger caverns and laboratory rooms being considered for the same 4850 Level. Provision for rock mass variability, sequential excavation, jointing and wall damage from blasting are included in analyses that were done using two different computer codes and methods (FLAC3D and UTAH3). The results are in agreement with observations and show that cavern stability is indeed the case. The main conclusions are: (1) if conventional scaling of laboratory rock elastic moduli and strengths is done, then 0.25 and 0.50 scale factors are reasonable, (2) measured statistical and spatial variability in rock properties should be incorporated into geomechanical analyses to better reflect reality, (3) discontinuities (“joints”) are essential to reliable analysis of excavation safety and when properly taken into account eliminate the need for empirical “scaling” of laboratory rock properties, (4) major geologic features such as rhyolite dikes and breccia zones may be important to excavation safety at Homestake and should be explicitly represented in analyses and (5) quantifying wall blast damage is important to engineering design of underground excavations.

Jan 1, 2012

By Richard DePew, Robert J. Auber

The Westerly Storage Tunnel is a 25-foot diameter segmentally lined storage tunnel that is a major component of the Northeast Ohio Regional Sewer District's Project Clean Lake that is designed to capture 39 million gallons of untreated CSO overflows from entering Lake Erie. During the final stages of the project completion, a large-scale rock fallout incident occurred during the final lining installation operations at the down-stream end of the tunnel that extended beyond the designed primary support system. This paper outlines the level of coordination and collaboration between the Owner, Designer and Contractor to remediate the situation safely, quickly and effectively.

Jun 23, 2024

By R. H. Mullennex

Application of depositional analysis concepts is becoming an ever-increasingly more important and more useable tool in exploration and development of coals in the Appalachian basin. Over the past decade, a rather large number of studies, papers, and publications have addressed various aspects of depositional environments of coals and, to some extent, applications to development. As would be expected as regards a subject so complex as Pennsylvanian sedimentation in the Appalachian basin, certain academic studies have produced conclusions at variance in some aspects to those of other studies. Overall, however, there has been a building- block progression and general refinement with time of understanding of the depositional settings and other factors controlling Appalachian coal distribution, quality, and other minability parameters. Most attempts to explain coal seam characteristics have revolved around a basic deltaic model. Some have attributed certain seam attributes to upper delta plain deposition, other attributes to transitional-lower delta plain settings, and yet others to lower delta plain environments, and so on. While these approaches have provided valuable insight into some general coal characteristics, they are somewhat incomplete and are, in a sense, too broad for specific mine-scale applications. Further, it is apparent that in order for widespread peat accumulation to occur, there must be a drastic decrease in the energy of the depositional system and amount of sediment being brought in, compared to the active deltaic and coastal processes responsible for deposition of the large volume of clastic sediments that dominate the Pennsylvanian system of the Appalachians. Consideration of this fact implies that peats (coals) may not necessarily reflect depositional settings that are directly coincident with those associated with adjacent rocks. Cecil and Englund (1985) address this point, and quite correctly state that "the primary controls on major stages of peat formation are allocyclic processes involving paleoclimate, eustatic changes in sea level, and tectonics." While this statement is inarguable, it does not negate the importance and usefulness of depositional analysis in predicting reserve characteristics that may impact mining and marketability.

Jan 1, 1986

By S. K. Bhatt

This paper reviews major developments in continuous haulage technology for underground coal mines. Haulage systems, both in use and development, are investigated through a comprehensive literature search and visits to mines and manufacturers. The systems include flexible conveyor train, mobile conveyor, multiple-unit continuous haulage, extensible, and belt turning systems. Strengths and weaknesses of the systems are assessed in light of their operating under remote control and their application to the computer-assisted continuous mining machine being developed by the U.S. Bureau of mines. Through mining scenarios, candidate haulage systems are conceptualized to be consistent with the capabilities of the mining machine.

Jan 1, 1990

By Donald W. Foss

The Shiloh Church deposit is a very significant molybdenum occurrence in an ususual, perhaps unique, geologic environment. Work done to date indicate that several million tons of "ore" may be present, occurring as a matrix in limestone and dolomite breccias. Mineralized rocks cored to date are at or near the surface and the deeper resource potential has not been tested. The prospect is located in Polk County, north- western Georgia (Fig. 1). The "ore zone" was outlined by North American Exploration, Inc. (NAE) using geochemical prospecting techniques. Extensive geological work, including core drilling, has been conducted on the properties, together with geochemical and geophysical surveys. The geology, geochemistry and geophysics of the prospect are discussed. It is hoped that these data can be used to formulate exploration programs in similar terranes located elsewhere in the eastern U.S.A.

Jan 1, 1983

It had been more than a decade since this many booths were occupied at an SME Annual Meeting, but at the 2010 meeting in Phoenix, AZ 630 booths were sold to 470 vendors from the entire spectrum of the mining and minerals industry. Exhibitors such as Metso, FLSmidth, West-Tech, ABB, NIOSH, Eriez and Resource West took their usual prominent places on the exhibit floor and were joined by newcomers such as tunnel boring machine manufacturer Herrenknecht AG, Frontier Kemper, the International Society of Explosive Engineers and more than 100 other first-time exhibitors. On the floor, one could find everything from a new pair of boots to a new career in the recruitment pavilion where some of the biggest companies in mining (Barrick Gold, Freeport-McMoRan, Newmont Mining, etc..) set up shop. The following is a look at some of the companies and products that were on display at the 2010 meeting. For information about displaying at the 2011 annual meeting in Denver, CO, Feb. 27 to March 2, contact exhibits@smenet.org.

May 1, 2010

One of the critical challenges facing the mining industry ? and not just in the United States ? is the looming labor shortage. A significant percentage of the industry?s professional workforce is, well, getting old, and many will be retiring in the next 10 years or so. This is not a new issue to the industry. It has been discussed at various industry meetings and conferences for many years. How does mining, with its largely negative public image, attract young people to mining schools? And, equally important, who is going to teach them? Mining schools, what?s left of them in the United States, are beginning to lose qualified faculty to retirements, and no one is available to replace them. SME addressed this issue during the keynote session at its annual meeting in February in Denver, CO. This year?s theme was ?Mining: It?s About the People.? Despite a blizzard that blanketed the city on the day most attendees were to have arrived, the meeting still attracted a record 7,202 people. And the accompanying exhibit sold 822 booths, also a record. The U.S. Department of Energy?s National Energy Technology Laboratory contracted with the National Academies? National Research Council to complete a study concerning the availability of skilled workers to meet the energy and mineral security requirements for the United States. The National Research Council, in turn, asked SME to collect and analyze workforce trends in these industries. The result of SME?s analysis is the report ?Emerging Workforce Trends in the U.S. Energy and Minerals Industries.? It is available on the SME website, www.smenet.org. Click on Government Affairs. While the report did not paint a completely dismal picture, there were some disturbing results. It concluded that within 20 years there will not be a sufficient number of skilled professionals to satisfy the labor demand. That said, the report said that most of those positions would likely be filled. However, the U.S. mining will go through a period of time when the workforce will be made up of very young and senior workers.

Jun 1, 2013

By Russell B. Dix

Laboratory column leach tests are used routinely to evaluate gold and silver ores for heap leaching. The tests are fairly straightforward. The ore to be tested is placed into an appropriately sized leach column. Then an alkaline cyanide solution is applied to the ore and the effluent solutions are collected. The effluent solutions are then put through a column of activated carbon to recover the gold and silver in solution. Zinc precipitation may also be used for silver ores or if the ore contains a significant amount of soluble silver in addition to gold. The length of the leach time in the tests is mainly a function of how quickly the precious metals are recovered from the ore. At the completion of the tests, the tailings are assayed and the recoveries determined from the calculated head grades. The amount of ore to be used for a test is partly a function of its crushed size. The coarser the size, the larger the sample size for the column. A typical small-scale laboratory column test on ore crushed to -12 mm (-0.5 in.) would usually be conducted in a 100- to 150-mm-diam (4- to 6-in.-diam) column 2 m (6.6 ft) in height, containing about 20 to 45 kg (44 to 99 lb) of ore. A comparable test on the same ore crushed to 50 mm (2 in.) would be conducted in a 200- to 300-mm-diam (8- to 12-in.-diam) col¬umn 2 m (6.6 ft) in height, containing about 80 to 200 kg (176 to 441 lb) of ore. Larger-scale tests can be run by increasing the column heights and diameters. Conducting larger-scale tests results in increased costs for sample procurement, preparation, and running of the tests. The additional data obtained from

Jan 1, 1989

By John Sasadi

The mining industry depends upon inexpensive water transportation. Today, large quantities of mined products are transported by ships over oceans, from continents to continents, over lakes and waterways to the ultimate users. Sometimes, the routes these Bulk Carriers travel cover only a few hundred miles, sometimes thousands of miles halfway around the world. Most of the products of the mining industries are relatively inexpensive. A significant portion of their cost to the ultimate users are in the cost of transportation and not in loading and unloading these commodities at the ports of origination or destination. So far, the industry has produced very efficient loading and un- loading installations, but has very little influence over marine transportation or the design of the vessels themselves. Very little was ever published dealing with integrated transportation systems properly correlating all phases of the operation; namely, loading, marine transportation and unloading bulk materials.

Jan 1, 1967

By G. M. Wali Ullah, MEHMET KIZIL, ` Micah Nehring, PETER KNIGHTS

In operations that use the sublevel stoping mining method, production scheduling takes into account factors, including ore reserve envelopes, ore grade averages, equipment capacity, feed controls to the mill, and geotechnical restrictions, across the scheduling horizon. Mathematical programming is one of the most effective methods for enhancing the decision-making process in regard to the most viable production schedule in light of a given set of limitations. The majority of research on sublevel stope mining focuses primarily on a single objective of optimisation, which is to maximise the net present value (NPV). Environmental, social, and governance (ESG) considerations are becoming more prevalent in the mining industry. This includes aspects relating to deforestation, land disturbances, gas emissions, community relations, and water usage, among many others. Institutional and other kinds of investors are becoming more interested in the work that resource companies do regarding their ESG obligations. This review article identifies the gap in the existing literature and proposes to simultaneously optimise the production schedule around three objectives. Two of these relate directly to ESG aspects.

Nov 6, 2023

By Scott Rosenthal, David Gilkey, Michael McGivern, Lorri Birkenbuel, Daniel Autenrieth, Ty Murphy, Hadi Aldossari

A safety climate case study was carried out at a surface metal mine where investigators administered the Liberty Mutual Short Scale Safety Climate Survey to 365–368 miners to measure safety climate in consecutive years. Following the baseline safety climate survey in 2019, Foundations for Safety Leadership (FSL) training was conducted with 81 middle to upper management employees at the mine site. Investigators found statistically significant differences in the pre vs. posttraining FSL assessment scores of the middle to upper management employees who attended the training. The follow-up safety climate evaluation was compared to baseline scores and revealed no significant improvement. The overall baseline company safety climate score of 76.38 increased minimally to 76.50 (p-value = 0.616). Investigators also evaluated differences in safety climate between the company’s three major divisions (operations, maintenance, and administration). Both years administration had the highest mean score and operations had the lowest mean score. The authors attributed the statistically significant differences found among the three major divisions to various dissimilarities in their work environments.

Aug 13, 2021

The past four years since the 2008 MINExpo have been a roller coaster ride for the mining industry, with highs and lows and everything in between. One of the natural consequences of this uncertainty has been a number of significant consolidations and mergers, and this trend has trickled down into the crushing industry. And while there have been some significant changes to this sector of the mining industry, many of the big players have weathered the storm. The following is a look at some of the mineral processing companies that will be at MINExpo. McLanahan Corp. McLanahan Corp. is an example of the changes in the sector. The crushing and grinding stalwart acquired Universal Engineering, expanding its traditional focus on soft mineral crushing to hard rock crushing. At MINExpo, it will be showing off three new pieces of equipment, the LabMill Crusher, the Rocker Tooth Crusher and the Recessed Filter Press.

Jan 1, 2012

By Lawrence A. Engel

The idea of using apron feeders for in directly feeding crushers is not a new one, it has been used for many years. To the best of our knowledge, the first apron feeder was used for bulk material handling in 1893. Since that time many design innovations have been introduced, with perhaps the most effective one being, the application of crawler tractor components in the feeder construction. This design was first introduced to the mining industry in 1954 by, national iron company. These feeders were used in the handling of run-of-mine iron ore on the Minnesota iron range, at the rate of 1,000 ltph. The material was fed over a grizzly to a jaw type of crusher. The crusher output was also handled by an apron feeder. Today, the apron feeder is being used in hard rock surface mine operations feeding crushers at rates of 5,500 ltph and over.

Jan 1, 1983

By Amar Prakash, V. M. S. R. Murthy, Ajoy Kumar Singh, Avinash Paul, John Loui Porathur

Weak, layered, and fragile rock mass formation, if not supported properly, is subject to roof failure thereby affecting safety and productivity in underground coal mines. Though Central Mining Research Institute – Indian School of Mines Rock Mass Rating (CMRI-ISM RMR) based well-defined support design guidelines are established, still occurrence of roof failures in underground coal mines is a real matter of concern for mining engineers and researchers. Numerical modeling techniques are successfully used by several researchers by simulating rock mass condition for stability assessment of mine openings. The analysis becomes crucial in case of weak and fragile rock formation. The present research envelops the determination of 31 cases of rock load by CMRI-ISM RMR under different geo-mining conditions followed by the development of modified Rock Mass Rating (RMR), i.e., rock mass rating dynamic ( RMRdyn) by incorporating P-wave velocity as a new parameter. The rock load determined using RMRdyn and numerical models was correlated and found in close agreement. In addition, the deviation in rock load determined by all the three approaches, i.e., CMRI-ISM RMR, numerical modeling, and RMRdyn, was compared with the actual field data. The percentage deviation obtained in RMRdyn and numerical modeling is less compared to CMRI-ISM RMR.

Sep 1, 2023

By A. J. Basu

An overview of the evolution of computerized mine planning and design has been given, emphasizing the need for a knowledge-based system for planning and design of underground coal mines. An outline for the development methodology and procedure has been provided. Problem structuring guidelines have been used to incorporate intelligence and integration to the design modules. A skeletal model for a mine planning and design expert system has been prescribed, and the development process has been documented in detail. A feasibility prototype has been developed to test the structure of the skeletal model and to ensure completeness of the design process. The feasibility prototype development and its contribution toward proto typing has been addressed in this paper. At present, prototype development is underway. The prototype is expected to be avail-able for testing and implementation in early 1991.

Jan 1, 1991

By Yao Yevenyo Ziggah, Victor Amoako Temeng, Solomon Evans Kweku Koomson

Tyre hours/life deficit is a major operational challenge facing the mining industry which adversely affects materials production and costs. An accurate forecast of the tyre life is key in addressing this menace. This study for the first time employed the hybrid intelligent technique by utilising three metaheuristic optimisation algorithms, including particle swarm optimisation (PSO), genetic algorithm (GA), and whale optimisation algorithm (WOA), as trainers for the parametric weights and biases to optimise multilayer perceptron neural network (MLPNN) for enhancing prediction of on-site dump truck tyre life in the mine. Four hybrid models known as PSO-MLPNN, WOA-MLPNN, GA-MLPNN, and BP-MLPNN were developed using a total of 157 tyre dataset records obtained from a surface mine in Ghana. In assessing the prediction performances for the models developed, five statistical performance metrics of variance accounted for (VAF), Nash–Sutcliffe efficiency index (NASH), coefficient of determination (r2), mean absolute percentage error (MAPE), and correlation coefficient (r) were utilised. Moreover, ranking, uncertainty analysis and Bayesian information criterion (BIC) techniques were utilised to establish the most effective hybrid model, whereas sensitivity analysis was conducted on the input parameters. Results achieved showed that PSO-MLPNN was the best for prediction because it had the least MAPE value of 1.196% and relatively high values of VAF (99.642%), NASH (0.996), r2 (0.996), and r (0.998). Besides, PSO-MLPNN had the best selection criteria values of 6, 7.1725, and 444.834 for the ranking, uncertainty analysis and BIC respectively. Hence, PSO-MLPNN is recommended for the prediction of on-site dump truck tyre life for the studied mine.

Mar 11, 2024

By Angela Binder, Mareike Schubert, Yichen Jiang, Sandra Nowosad, Oliver Langefeld

GermanyINTRODUCTIONThe mining industry is currently characterized by various factors such as environmental impact, resource scarcity, social responsibility and geopolitical uncertainty. The production of minerals required to meet the demand for renewable energy is expected to increase by 500 % by 2050, particularly for critical minerals such as graphite, lithium and cobalt 1. Easily accessible deposits are often depleted, meaning that deeper and more complex deposits need to be developed. Furthermore, investors’ value systems have shifted towards more sustainable practices. Alternative approaches to solving this problem are therefore currently being developed, such as the Modular Mining Systems concept for scalable and adaptable mining projects 2. Many mining companies have also taken important steps to become more sustainable, implementing measures such as proactive closure strategies, restoration programs and the development of renewable energy projects. In the European Union, laws such as the Critical Raw Materials Act and the Net Zero Industry Act support the mining industry 3,4. They see it as important for the energy transition and promote more sustainable ways of working in the industry Particularly negative environmental impacts such as land degradation, scarcity of local water resources, water pollution and greenhouse gas emissions are ingrained in society’s memory. Despite these efforts, the public image has not yet changed. To change this perception, the industry must strive to better communicate its sustainable practices and the steps it is taking towards a more responsible and sustainable future, promote transparency and build trust.Digitalization, automation and electrification are driving the digital transformation in mining. However, their implementation can lead to higher capital expenditure, limiting their adoption across the industry. Furthermore, implementing new technologies can be a daunting task for any organization. Change management comes into play when introducing such disruptive technologies. It involves preparing an organization for change, potential resistance and establishing effective communication. This helps to ensure that the implementation is successful and the benefits of the new technology are maximized. Digital transformation requires well-trained, young mining, electrical, mechatronic and software engineers with a deep understanding of information systems. Unfortunately, the industry faces the enormous challenge of attracting this younger generation, who have little interest in the extraction of raw materials. The need for action is compounded by an aging active workforce heading into retirement and the forecast of increasing demand for critical minerals.In this challenging environment, the concept of Blue Mining with its constant further developments represents a promising approach. This implies a shift from a linear to a sustainably oriented circular economy. For the mining industry, this specifically means the introduction of innovative technologies, the increased recovery of materials from waste and the consistent questioning and application of circular principles along the entire life cycle of a mine. Such a change can not only reduce the environmental impact, but also contribute to economic resilience and increased social acceptance of mining.

Feb 1, 2025

By Pratima Meshram Abhilash

In this review, availability of germanium in primary and secondary resources and its recovery from these resources are presented. With nearly 40% germanium consumed in fiber optics and scarcity of resources, the global consumption outplays the primary production. Germanium exists as a substituted element in zinc sulfide matrix of lead–zinc sulfides and lignites. Nearly 60% of the germanium supply is met by zinc refining residues, and about 20–30% of germanium is produced from coal and its by-products. Germanium recovery from various resources such as zinc plant residues, coal and coal plant waste, spent optical fibers, and copper flue dust has been examined. Bioleaching was exploited by few researchers to extract germanium from zinc sulfides, sulfide tailings, jarosite, coal fly ash, and flue dust. This review covers the various work carried out by different chemical separation processes, viz., chemical precipitation, solvent extraction (SX), ion exchange (IX), and membrane processes, as well as biological approaches.

Jan 16, 2022

By Siddhartha Roy, Hemant Agrawal, Ram Madhab Bhattacharjee, Devi Prasad Mishra

Heat stress in underground coal mines is a major threat to the health and safety of the miners. Hence, managing heat and prediction of heat stress in advance is essential for maintaining a safe, healthy, and productive underground mine environment. In this study, an extensive ventilation survey has been carried out in three different deep and mechanized underground coal mines. The ventilation survey data are used to develop 3D simulation models with the VentSim™ software to predict the conditions that could cause heat stress in underground mine workings. The developed 3D models predicted well the wet-bulb globe temperature (WBGT), a recognized indicator of potential heat stress, with a coefficient of determination (R2) of 0.986, 0.994, and 0.993 for Mine-A, Mine-B, and Mine-C, respectively. Moreover, through 3D modelling, the applications of auxiliary ventilation and spot coolers to reduce the wet-bulb globe temperature (WBGT) for improving the underground workplace environment have been explored. The study demonstrated that auxiliary ventilation and spot coolers can help in significant reduction of heat stress conditions in an underground mine environment. By application of auxiliary ventilation, to increase air volumes, and spot coolers, the WBGT index in mining faces is reduced by 1.2–1.4 °C and 3.9–5.4 °C, respectively. Therefore, it is concluded that the spot coolers are more effective in reducing the heat stress conditions in hot and humid underground mine environments in comparison with auxiliary fan that is used to increase the air volume and velocity. This study opens up a new horizon of 3D simulations for heat stress management in underground mines. The outcome of this study will be useful for the researchers, mine operators, and environmentalists understanding the heat stress contributors and their control in underground mine environment.

May 10, 2023