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By N. L. Bingham

The mining industry's image is molded by what the general public knows, or thinks they know about mining. As we prepared for the production of Caterpillar's educational film, Common Ground, we first had to find out exactly what the public perceptions about mining were. Before we could educate people about mining, we had to find out what they already thought. As we broke down those perceptions, we were able to narrow our focus to relevant, realistic approaches for the film. We found out what people didn't know about mining. And most importantly, we singled out the facts they should know... facts that could create more favorable attitudes. This research was instrumental in our final direction for the Common Ground project.

Jan 1, 1994

By K. J. Ma, L. Ma, J. Stankus

The paper’s intent is to evaluate pumpable foamed cementitious mine seal material by determining the shear strength of a generic foamed cement in the laboratory. The tests were conducted on three scales: small-size specimens, consisting of cylinders 4 in. in diameter or 3-in. prisms; double shear medium- size specimens, measuring 13 in. by 10 in.; and large-size specimens, measuring 6 ft by 4 ft by 4 ft. The small-specimen shear tests resulted in average peak and residual shear strengths of 128 psi and 56 psi, respectively. These values are fairly consistent with published shear strengths of foamed cementitious material. However, the other two types of shear tests did not achieve the shear strength of a typical pumpable foamed cementitous mine seal material. Based on the test results, the paper concluded that the structural analysis of cement foam seals should be based on their residual shear strengths, approximately 20 psi, determined from small laboratory-scale tests of the cement foam/concrete or rock interface, and not be based on their peak strengths.

Jan 1, 2015

By NILAMADHABA SAHU, Gajanan U. Kapure, Pankaj Kumar, Sunil Kumar Tripathy

Chromite ore processing tailings and low-grade manganese ores are typically considered waste due to their limited or negligible utility, leading to environmental and storage concerns. Researchers globally have explored various methods to utilize or upgrade these wastes, particularly because dumping chromite ore has been linked to severe health issues through Cr(VI) leaching. Individually, these ores lack economic value, and there has not been research on simultaneously reducing both low-grade ores. In this study, the focus lies on smelting these ores together, aiming to create a precursor alloy for 200 series stainless steel scrap. Initial research indicates the potential for scrap formation, validated through laboratory experiments with varying coke rate, basicity and holding time. The investigation discovered that smelting this combination could yield a metal product consisting of 59 percent Fe, 24.93 percent Cr, 7.56 percent Mn, 0.62 percent Ni and 0.93 percent Si. The optimum basicity was found to be 0.6 with 80 percent recovery. Notably, this process eliminates intermediate steps in 200 series stainless steel production, potentially reducing overall carbon dioxide emissions. This proposed method represents a cleaner, sustainable approach to repurpose these two waste ores, projecting a net profit of US$330/t.

May 1, 2024

Residential and commercial plumbers in the United States were introduced to Viega?s copper press technology in 1999. In short, the technology allows plumbers and installers to join copper pipe securely in four to seven seconds on pipe sizes of 1.2 to 10 cm (0.5 to 4 in.) by pressing the connections with specialized tools and fittings rather than through sodering or welding. The water- and air-tight technology, first introduced in Germany in 1989, includes three different sealing elements, a variety of materials and a selection of configurations. By eliminating the need to thread or solder pipe, connections and repairs can be made quickly and securely. Installations are also much quicker and as secure as traditional methods.

Jan 1, 2012

By Kwangmin Kim, Taehee Lee, Minkyu Kim, JUNHYEOK PARK

Mine tailings storage facilities (TSFs) can be a significant source of fine, respirable dust. About 25 percent of the mass fraction of tailings from a hard-rock mine consists of particles of a respirable size (smaller than 10 μm) [1]. This dust poses concerns, especially for nearby communities, because of its detrimental impact on respiratory health. Respirable tailings dust, primarily composed of quartz or free silica (SiO2), may cause silicosis, chronic pulmonary disease, bronchitis, collagen vascular diseases, and chronic granulomatous infections [2]. 

By CLAIRE STREBINGER, ADITYA JUGANDA, JURGEN F. BRUNE, GREGORY E. BOGIN JR.

Methane gas explosions are a major risk in underground coal mining operations. The severity of such explosions can range from local area damage to massive loss of miners’ lives along with significant damage to mine infrastructure and ventilation controls that may lead to mine closure and loss of the entire operation. This study demonstrates the viability of integrating a computational fluid dynamics (CFD) combustion model into a longwall mine ventilation model to simulate methane gas explosions in the longwall face area. The resulting 3D methane gas explosion simulation can provide better understanding of the fundamental physics and the potential impact of an explosion in an underground longwall coal mine.

Aug 1, 2022

"The 33rd annual American Mining Hall of Fame Awards Banquet and Fundraiser sponsored by the Mining Foundation of the Southwest (MFSW) will be held at the JW Marriott Tucson Starr Pass Resort & Spa on Saturday, Dec. 5, 2015. Each year, one living Hall of Fame inductee, two Medal of Merit recipients, several honorees from Mining’s Past, an Industry Partnership Award and a Special Citation are recognized for their respective contributions to the mining industry.Conrad E. Huss, cofounder of M3 Engineering & Technology Corp. located in Tucson, AZ, will be honored as the 2015 Hall of Fame Inductee and will serve as the keynote speaker at the awards banquet. Huss has served his company as chairman of the board for its entire 30 years and guided M3 to become a full discipline firm. Now M3 offers complete project execution through engineering, procurement and construction management procedure and has become a major engineer of large observatories around the world. The company now has more than 1,000 employees with offices in Arizona, North Carolina, Mexico, Argentina and is incorporated in Guatemala, Peru and Canada.The Medal of Merit will be awarded to Charles Michael (Mick) Lownds, founder of his eponymous consulting firm in Salt Lake City, UT, for his 42 years in commercial explosives following tenure at Sasol and at Orica. Originally from South Africa, Lownds immigrated to the United States in 1998 and has made significant advancement on electronic initiation systems. Lownds has published numerous technical papers, is an inventor with 12 awarded United States patents and was also the recipient of the President’s Award from the International Society of Explosives Engineers in 2000.Medal of Merit for young professionals will be awarded to Fiorella Giana, Freeport- McMoRan Inc.’s (FCX) mine manager at Bagdad. Born in Buenos Aires, Argentina, Giana left the small cattle farm where she was raised in 2001 to pursue higher education in the United States. For the past decade at FCX, as a result of her extraordinary combination of technical skill, leadership and commitment to excellence, she has been given positions of progressively greater responsibility from an entry level engineer to senior mine engineer, to chief engineer and now as mine manager, a position rarely held by woman."

Jan 1, 2015

By S.K. SHARMA, ANKUSH GALAV, G.S.P. SINGH

This paper proposes a hydromechanically coupled numerical modeling approach to quantify the influence of various parameters on the mechanical and hydraulic performance of protective water barrier pillars (PWBP). The results are validated for two case studies having pillar widths of 16 and 42 m at cover depths of 136 and 190 m and water heads of 25 and 141 m. The outcome can be significantly helpful in the rational design of these pillars in underground coal mines.

Mar 1, 2023

By HONGWEI YANG, Lili Zhang

Copper slag is mainly used in cutting tools, abrasives, asphalt pavement, road construction, and in the production of concrete as an alternative to sand and cement [1]. As a renewable resource, only about 15-20 percent of the slag is used for these applications, and the dumping or disposal of surplus unused slag results in waste of a certain amount of usable metal in the feedstock [2]. In this work, the oxidation behavior of copper smelting slag under nonisothermal condition is studied using data obtained by the thermogravimetric (TG) method, and the kinetics parameters and reaction mechanism of oxidation are determined. It provides a theoretical basis for the comprehensive recovery of iron resources in slag and the selection of reasonable slag-making conditions.

Oct 1, 2022

By STEVEN J. SCHATZEL, Zoheir Khademian, KAYODE M. AJAYI

The integrity of unconventional shale gas well casings positioned in the abutment pillar of a longwall mine could be jeopardized by longwall-induced deformations. Under such scenarios, the surrounding fracture networks could provide pathways for gas flow into the mine, creating safety concerns. To provide recommendations for developing guidelines that ensure a safe coexistence of longwall mining and unconventional shale gas production, this study uses a discrete fracture network (DFN) model to evaluate the impact of parameters that could affect potential shale gas flow into the mine in the event of a casing breach. These parameters are evaluated using a conceptualized DFN realization that is representative of the fractured zone in the overburden, and the range of parameter variations are within values validated with field measurements.

Mar 1, 2023

By MYRIAM FRANCOEUR, JOHN R.R. BOWLING, ADAM MCFADDEN

As duct-fan systems push the envelope of power, length and cost, their design calls for a more comprehensive technoeconomic analysis to ensure they deliver the expected results without failure and cost overrun. This work explores the numerous factors to include in the design of an extensive (semi-)rigid duct-fan system. Besides delivering a given airflow, the system must satisfy component limitations and power constraints during its lifetime. We evaluate the assumptions underlying the positioning of in-line booster fans in a long gapless duct-fan system and propose a strategy for specifying the location and blade pitch of successive booster fans to prevent system failure due to a partial vacuum.

Oct 1, 2022

By SONGHE WANG, YI XUE, PENG HOU, CAIHUI ZHU, XUANYE JIAO, Feng Gao

Coalbed methane development is an important way to effectively realize a source of clean energy and reduce emissions of carbon dioxide and other gases. However, due to the low permeability of coal seams, the development of coalbed methane in China has encountered substantial barriers. Protective layer mining can efficiently minimize in situ stress and increase coal seam permeability, thus improving gas drainage and avoiding gas disasters. This study analyzed the characteristics of gas migration and the change in permeability during the in situ stress releasing process through experiments and numerical simulation to study the gas drainage effect of a coal mine in an unloaded coal seam under specific geological conditions. First, a stress–strain-seepage coupled test of coal was carried out, and the evolution features of coal permeability during stress loading and unloading processes were investigated. Second, experimental results were used to develop a mathematical model of coal seepage under mining unloading conditions. Finally, a numerical model was developed based on the real geological conditions of the Wulan coal mine to explore the characteristics of in situ stress release and permeability evolution, as well as the gas drainage process in an unloaded coal seam. By combining protective layer mining and gas drainage technology, the risk of gas outburst is significantly reduced.

Oct 1, 2022

By Taghi Sherizadeh, KUTAY E. KARADENIZ, Dogukan Guner, Samuel Nowak

Underground mining environments bring with them occupational health and safety issues with some severe dangers, such as mine explosions. During such events, miners may escape using main access openings or find a safe haven like a refuge alternative (RA) to wait and be rescued and evacuated to the surface. In this paper, RAs are explained with their early and current applications. A classification as permanent and portable is detailed, depending on conditions and abilities. This classification is followed by the utilization and survivability of RAs with the requirements and recommendations of the main mining countries. Based on the utilization and survivability constraints, basic human requirements, waiting for a rescue team, and the required physical specifications of RAs during the events are analyzed in detail for various countries with their regulations. Among these, the specification of resistance to explosion is discussed in particular, and studies in the literature are examined in terms of structural deformation.

Mar 1, 2023

By Wedam Nyaaba, Edward Wellman, Angelina Anani, Eduardo Cordova, Sefiu O, Cluber Rojas, Adewuyi

This study aims to investigate the optimal method for ore pass construction in incompetent rock masses. We evaluated the conventional and raise boring methods based on safety, efficiency, excavation control and ground support for ore pass construction. A stability analysis using analytical Q-raise (QR method) and kinematic analysis methods for ore pass construction with a raise borer before and after grout injection of the rock mass was performed. As a case study, an ore pass (diameter of 3 m, depth of 100 m) within an incompetent rock mass was considered to gain further insight. The rock mass was characterized according to the classification methods Q Barton, rock quality designation (RQD), rock mass rating (RMR) and geological strength index (GSI). The grout intensity number (GIN) method of grout injection was used. The safety factor of less than 1.075 obtained before injection was lower than the acceptance criteria. However, grout injection before raise borer excavation resulted in a safety factor greater than 1.5. Using a raise borer without pre-grouting indicated that the maximum unsupported diameter (MUSD) of the ore pass was less than the required 3 m and equal to or larger than 3 m post-grouting.

Dec 1, 2024

By K. Mohamed, G. Rashed

A conventional mechanical anchor bolt consists of a smooth bar threaded at the anchor end, with a conical wedge, and a mechanical shell anchor. When the smooth bar is torqued, the conical wedge pushes the shell anchor against the borehole wall. Coal mines use mechanical bolts in addition to other types of bolts to control the deformation and stabilize the yielded coal ribs. Limited research has been conducted to understand how a mechanical anchor performs in a coal rib. Researchers from the National Institute for Occupational Safety and Health (NIOSH) conducted the study described in this paper to define the loading characteristics of mechanical bolts (stiffness and capacity) installed in coal ribs at five underground coal mines. Standard pull-out tests were performed in this study to define the loading characteristics of a mechanical rib bolt. Based on the strength of the coal seam and the conditions of the coal mines, the bolts were installed at different amounts of torque. A typical tri-linear load-deformation response was obtained from these tests. It was found that the anchorage capacity depends on the coal strength, and the anchorage stiffness depends on the installation torque. The outcome of this research provides essential data for rib support design. INTRODUCTION Rib falls are a serious hazard in underground coal mines. In the last 10 years, rib failures have resulted in 17 fatalities, representing 52% of the ground-fall fatalities in underground coal mines in the United States (MSHA, 2018). Although resin bolts has been used increasingly in the last few years to control coal ribs, mechanical bolting (mainly expansion-shell bolts) is still used in many underground coal mines. Recently, NIOSH researchers surveyed 90 sites in 14 underground coal mines in the Eastern United States and found that 79% of the mines determine their rib support requirement based on the depth, mining height, and the loading conditions, of which 35% use the conventional mechanical bolts. Conventional mechanical bolts are preferable for rib support because they do not require the miners to be too close to the rib during rib bolting. Hence, using the conventional mechanical rib bolts can reduce the risk of injuries and fatalities during the installation process. The mechanical bolt or the point-anchored bolt is the oldest type of rock bolt that is still in use today. The point-anchored bolt is a tensioned bolt anchored down the hole with a mechanical expansion shell or a grouted medium (Peng and Tang, 1984). Figure 1 shows the components of the mechanical anchor bolt. The mechanical anchor bolt consists of a plug, a shell anchor, a headed smooth bar with the top end threaded, a bearing plate, a hardened washer, and sometimes a friction-reducing washer. The shell anchor can be either standard or bail type. The shell of the standard type is held in place by a nut, while the bail anchor uses a strap to hold the shell in place (Peng, 2008). The diameter of the smooth bar is generally 5/8 in for the #5 bolt or 6/8 in for the #6 bolt. The diameter of the hole that the bolt is inserted into must be carefully controlled since an oversized hole can result in poor anchorage (Moss, 1971). The anchorage is obtained by applying torque to the bolt head, which in turn pulls the wedge down in the shell and expands the serrated leaves against the sides of the hole-wall. In the resin-grouted anchor, the resin replaces the mechanical expansion shell at the end of the hole. The anchorage is achieved by bonding between the resin, bolt, and the hole-wall.

Jan 1, 2019

By Ryne Goodnough

INTRODUCTION The Wyodak Mine is located in the northern Powder River Basin of Wyoming and is thought to be the oldest continuously operating coal mine in the United States, having recorded yearly production since 1923. The mine has expanded over its 80-plus-year history from an underground room and pillar operation to a modem surface snip mine. Currently, the mine feeds four on-site power plants using conveyors, has a filly automated truck load-out, and ships coal by rail to nearby Wyoming power plants. Annual production of 4.8 MTFT is accomplished on a single-shift basis with 53 fill-time production, maintenance and administrative personnel. In 1990 a decision was made to modernize the coal feed system to the power plant complex with modular conveying equipment. The project involved constructing coal storage silos, overland conveyors, feeder breakers and modular conveyors to follow the mining benches. Total project cost in excess of $25 million was used to construe or commission: A 2,150-TPH 48-inch overland conveyor with horizontal curve A 2,150-TPH 48-inch plant feed conveyor 13 shuttle conveyors, each 150 feet in length 2 front-end loaders equipped with large coal buckets 2 crawler-mounted feeder breakers with compatible discharge conveyor 1 high-lift shuttle conveyor with adjustable discharge height 1 high-angle conveyor 2 4,500-ton coal silos with automated truck load- out capabilities. Conceptually, the plan was to develop 33 MTONS of reserve adjacent to the plant complex and use front-end loaders to tram ROM coal to in-pit feeder breakers. The primary crushing would reduce coal to 6-inch minus and feed through a series of shuttle conveyors to an overland supply conveyor. The overland conveyor would feed the secondary crusher, and the crushed product would be moved to any of four storage silos using conveyors. The in-pit crushing and conveying system is a unique fit for the power plants and provided many interesting challenges for the coal mine to overcome. System integration, maintenance windows, equipment availability and the like had a major role in engineering the system to a power plant complex having no emergency coal stock- pile and limited plant storage. In crediting the designers and operators, the in-pit conveying system at the Wyodak Mine has delivered coal to the power generators since 1994 with little or no downtime. ENGINEERING CONSIDERATIONS Yearly production for the mine is based on 3.5 MTPY which requires about 1,550 TPH on an 8 hour, one-shift- per-day, 5-days-per-week basis. Considering efficiencies for starting and stopping, crew transport, loader trams, and operational delays, a nominal conveyor feed rate of 2,150 TPH or 72% system utilization was used in engineering design application. This ton-per-hour basis is used to size and commission the remaining components of the in-pit system. Coal quality requirements also played a role in equipment selection. The mine reserve grades vertically and coal from Upper and Lower benches needed to be mixed in any given proportion. This required equipment to be filly variable and capable of producing all or part of the 2,150-ton-per-hour requirement. Bisecting the 80-foot- high coal face for quality required construction of a high lift module capable of reaching a single overland conveyor 40 to 50 feet above the pit floor. Designers built a high-lift, adjustable and portable module specific for this application Having two bench systems capable of each producing the required feed for the power plants required computerized control processes to control on-line production. RSLinx, RSLogix, and RSView were chosen as the communication and control software, and a Data Highway Plus serves as the communication backbone. Each of the two in-pit benches are controlled with a data center equipped with Allen Bradley 5-40 processors. This

Jan 1, 2004

By William Gleason

During the past five years, mining operations have had access to press technology for piping and joint fittings that can save owners a significant amount of time when installing or replacing pipes by eliminating the need for welding or threading. Viega, with North American headquarters in Wichita, KA, entered the mining sector in 2009, adding to its already expanding industrial sector. Since then, the company?s global engineering department has paid considerable attention to its industrial division, bringing its expertise in plumbing solutions for residential and commercial buildings to the mining and mineral extraction industry. ?We have a lot of applications in the mining industry.?We have a lot of applications in the mining industry throughout the United States, Canada and Mexico and continue to expand in the mining industry,? Tom Shields, Viega?s director for industrial accounts explained. ?Since we made the decision to increase our presence in the industrial markets, we have been aggressive and more than 240 applications have been approved by our engineering department in Germany.? Getting approval from Viega?s engineering department is no small feat. During a tour of the manufacturing facilities in Ennest and Großheringen, Germany, Mining Engineering, as well as a select few other publications and clients, were shown Viega?s manufacturing process. At the Ennest facility, hundreds of millions of fittings are produced, and each one is inspected mechanically and with a laser at the end of the production line. With four production facilities in Germany and one in the United States, Viega is able to ship to anywhere in the world. The company distributes everything from fittings to stainless steel pipe.

By Mokhinabonu Mardonova, Yosoon Choi

Open-source technology to support Industry 4.0 has become the target of academic research in many sectors. This study reviews the trends of open-source technology, its forms, and some industrial applications. As a case study of the use of open-source hardware and software in the mining industry, this study proposed a low-cost environmental monitoring system for nonmetallic underground mines to support mine safety and occupational health. The system was developed using open-source hardware, Arduino and 3D printer, to design the monitoring device, and open-source software, MIT App Inventor, to develop an Android application for smartphones to enable remote communication with the system. Field experiments were conducted at an underground tunnel and a nonmetallic underground mining site to assess the performance of the system in mobile and static modes, respectively. Although a few limitations related to the precision of the low-cost dust and gas sensors exist, the findings of the experiments show that the mining industry can benefit from open-source technology deployment when considering cost factors.

By Yi Luo, Jian Yang, Hua Jiang

Surface subsidence events induced by underground longwall coal-mining operations can cause various disturbances to surface structures, ranging from integrity and stability to functionality problems. Highway bridges, as a kind of special road construction that can only tolerate smaller movements and deformations than road pavements, are particularly susceptible to severe influence caused by subsidence-induced ground movements and deformations. However, based on accurate subsidence prediction and correct influence assessments, efficient and effective mitigation and remediation measures can be designed and implemented to ensure the continuous service of bridges, safety of travelers, and smooth mining operations. In this paper, based on the predicted final and dynamic surface movements and deformations, the techniques to assess subsidence influence on the integrity, stability and functionality of bridge structures (such as decks, beams and abutments) are presented. A number of mitigation measures to protect bridge structures are recommended, along with an actual application case.

By PATRICK R. TAYLOR, NICHOLAS BELLUSCI, D. ERIK SPILLER, VICTOR BRAMAN

Most of the world’s production of natural soda ash comes from the mining and processing of trona found near Green River, WY. The processing of trona ores to ultimately yield a high-quality dense soda ash product and reject the insoluble gangue species, primarily in the form of oil shale, is water and energy intensive. It is speculated, however, that the glass-manufacturing industry, which is the largest consumer of soda ash, may be able to use product of a lower grade and consistent level of the insoluble constituents. Thus, the viability of using sensor-based sorting to produce a beneficiated trona stream that would be fed to calcination was investigated. The study encompassed the preparation of a run-of-mine (ROM) Green River ore sample; selection of specimens sized 25 to 75 mm; imaging of the specimens by sensors based on X-ray transmission (XRT), color and laser-induced fluorescence (LIF); insolubles analysis of the specimens; and a bench-scale sorting test. Results of the study established that a correlation between the color of the individual ore particles and their insoluble content exists, and that a surface-detection-based sensor, particularly LIF, is apparently more suitable than XRT to produce a beneficiated trona stream. The bench-scale sorting test demonstrated that a 65 percent separation efficiency and a 70 percent recovery of trona could be achieved.

Feb 1, 2023