Search Documents

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

By Bryan Ulrich

On March 20, 2014, the ?Roundtable Discussion on Innovations in Heap Leaching and Mine Waste Management? was hosted by Knight Piésold and Co. at the Red Lion Hotel in Elko, NV. This topic is timely, and formed something of a lead into the inaugural ?Workshop on Innovations in Waste Rock, Tails and Heap Leach Management.? That workshop, which grew from the 2013 Elko Roundtable, was held on the University of Nevada, Reno (UNR) campus on May 19, 2014. The workshop was hosted by UNR and the University of British Columbia. Knight Piésold?s local representatives, Bryan Ulrich and Logan Jensen, were joined by Tom Kerr, president of Knight Piésold?s, U.S. practice; Rick Frechette, senior vice president, environmental services and Jeff Coffin, geotechnical engineer, from the Denver, CO office for the roundtable event. The event played host to about two dozen attendees from several western states.

By James N. White

Completion of the Hall Street Coal Transfer Terminal in St. Louis marks the beginning of a major shift in the movement of coal to the power generating stations of the Midwest and South Central regions of the United States. The location of the terminal is significant. The 10 million ton- per-year facility is the first high capacity rail-to-barge transfer terminal to be built on the western shore of the Mississippi. This terminal and others to follow will link the massive coal fields of the West with the high coal consuming markets adjacent to the 25,000-mile Inland Waterway System.

Jan 1, 1979

By Gary Brierley, Lok Home

"The majority of tunnels for civil engineering applications are now being constructed using some form of mechanical excavation. Beginning in the 1960s with rock tunnel boring machines (TBM), the tunneling industry has introduced both earth pressure balance (EPB) and slurry pressure balance (SPB) soil machines; mixed soil and rock machines and a variety of different mechanical devices for the construction of small diameter tunnels. Over time, these machines have become more powerful and more adaptable to a wider variety of ground conditions; so much so that tunnels are now being constructed in ground conditions and in the vicinity of third-party impacts that would have been considered beyond the state of the art just 10 years ago. Figure 1 is an example of a mixed ground crossover TBM used successfully at Mexico City’s Túnel Emisor Poniente II.All of the above is highly advantageous for the tunneling industry, but it has also placed a much higher level of risk on the performance characteristics of the tunneling machines, on the contractors operating those TBMs and on the manufacturers of those machines. Most of the risks for a tunneling project are associated with creating the space inside of which the finished facility will be constructed. In order to create that space, the tunnel contractor must make many decisions about the best way to excavate the ground, the best way to control the ground at the face of excavation and the preferred method for supporting the ground around the tunnel in a manner that is safe for the workers and stable with respect to all of the overlying and adjacent existing structures. If it is proposed to use some form of TBM in order to build the tunnel, then the TBM becomes central to all three of these activities and becomes an integral part of managing the risks associated with these activities."

Jan 9, 2018

By Emily Wortman-Wunder

While the mood at the 2013 annual joint meeting between the Pittsburgh Coal Mining Institute of America (127th Annual Meeting) and SME Pittsburgh Section (68th Annual Off-the-Record Meeting) in Canonsburg, PA was subdued following a rocky year in the coal industry, attendance was down only slightly, to 300, and overall, the meeting?s focus was optimistic about the future of coal. The conference began by addressing one of the central challenges of coal mining head-on with a keynote address on the status of safety in the mining industry. Noting that two more U.S. miners had died in 2013 than by the same date in 2012, the National Mining Association?s (NMA) Senior Vice President of Regulatory Affairs Bruce Watzman made a plea for a new approach to safety. He described the NMA CORESafety initiative, a program that promotes proactive safety measures versus a compliance-driven model. CORESafety, described in more detail on pp. 29 of this issue, focuses on developing successful ways to change company cultures of safety and behavior. Other industries that have adopted this approach have seen dramatic drops in fatalities, including the Australian mining industry, which has seen its annual fatality rate drop to nearly zero even while the number of people employed in the industry has soared. The rest of the morning?s sessions explored what is arguably the industry?s biggest challenge right now ? maintaining the social license to operate.

Jan 1, 2014

By Anand Kumar, Debasis Deb, A. K. Mishra, M V. N. S. PRASAD.

In the Adriyala project, shield-leg pressure data from all shields and shearer location with time stamp from a mechanized longwall face are monitored and recorded in a surface computer. The data contain random noise due to power failure, leakage of legs, bad sensor readings, and other maintenance or geomechanical problems. An algorithm has been developed to detect mining cycle parameters such as setting and final pressures and duration of the cycle from these data for the analysis of periodic roof weighting phenomena. The intensities and persistence of periodic roof weighting are vital information for mine management to make judicious decisions on longwall operation.

By Qingming Feng, Jinhong Zhang

This study investigates the application of fly ash as a high-strength, water-resistant precast construction material through geopolymerization. The experimental results show that working conditions such as water content, sodium hydroxide (NaOH) concentration, curing temperature and curing time significantly affect the mechanical properties of the geopolymer matrix. Through optimization, compressive strength above 100 MPa was achieved, and the optimum working conditions were found to be NaOH concentration of 10 M, water content of approximately 14 to 15 percent, and curing at 90 °C in an oven for one day or at ambient condition for three weeks. Water-soaking tests show that the geopolymerization product has high water resistance without losing noticeable compressive strength even after one month of soaking time. The findings provide a novel method to apply fly ash as a high-strength, water-resistant precast construction material.

By S. D. F. Rocha, A. L. A. SANTOS, E. M. A. BECHELENI, F. P. C. Silvas

Hydrometallurgical processes are needed to extract nickel (Ni) when it is disseminated in mineral matrix. High-pressure acid leaching (HPAL) and atmospheric acid leaching (AAL) are alternatives, and AAL has the advantage of requiring mild temperatures and pressure. Reducing-reagent tests improved the extraction of metals for the specific limiting portion of the ore. Low dosage of sodium thiosulfate presented better selectivity and safer operating conditions, allowing metal extractions of 50–62 percent at 95 °C. However, the low extraction rate obtained for Ni and the similar levels of impurities — magnesium (Mg), manganese (Mn), cobalt (Co) and iron (Fe) — extracted may represent economical and technological challenges in the downstream process.

By Elif Emil-Kaya, Bernd Friedrich, Merve Papakci

Samarium (Sm), one of the rare earth elements (REEs), and cobalt (Co) are used in the production of SmCo permanent magnets, which have excellent temperature stability, corrosion resistance and oxidation resistance. Of the two types of SmCo magnets, one contains a high amount of iron, approximately 15.2 percent. This paper focuses on the recycling of iron (Fe)-bearing SmCo. In this study, an oxidative leaching process with nitric acid was developed to eliminate iron through in situ hydrolysis and to dissolve REEs and Co. The influence of experimental conditions on the formation of an amorphous iron compound through the hydrolysis of Fe3+ in a nitric acid environment was thoroughly examined based on a Taguchi orthogonal array. The optimal parameters for oxidative leaching were determined to be an acid concentration of 3 mol/L, a solid-to-liquid ratio of 1/10, and a process temperature of 60 °C.

Jul 1, 2024

"2016 marks an amazing accomplishment in the mining industry as Hecla Mining Company celebrates its 125th anniversary. Mining Engineering sat down with Hecla chief executive officer Phil Baker to gain insight on this tremendous longevity and to get his view on how the company demonstrated persistence, gained perspective and created position for its future.How did Hecla Mining Co. get its start?In 1891, a group of investors formed Hecla Mining Co. to acquire and trade mining claims. No one envisioned at the time that the Coeur d’Alene Mining District would become known as the “Silver Valley” and produce more than 37.2 kt (1.2 billion oz) of silver. Or that Hecla would become the United States’ largest primary silver producer and the last of the pioneer mining companies from this illustrious mining district.What is the origin of the name “Hecla?”That will forever be a bit of a mystery. Some say it was named for an Icelandic volcano. Or that it was the foresight of James Toner, who staked the original claim, that it would go so deep, fulfilling the medieval folklore definition of the word ‘Hekla’ which is the ‘Gateway to Hell.’ I kind of like that one as the Lucky Friday Mine is almost 3.2 km (2 miles) below the surface. It has operated for more than 70 years and has all the markings of being one of only a handful of mines that will exceed 100 years of operations.Is there a common theme, or thread throughout the 125 years?Yes, Hecla has always had a solid core of high-quality and long-lived assets, positioning the company to survive times of low prices and reap the rewards when cycles turn and higher prices are realized. But it is not just assets. Hecla has extraordinary expertise that gives us the perspective of how to acquire, explore, develop and operate mining assets, particularly underground. Hecla is one of the few companies to acquire assets in the last five to six years and we did not have to write down the value of them, which means we paid a fair price for the asset despite the metals price reductions that followed the purchase. And our culture has given us the persistence to develop mines and complete projects despite lower prices. For almost a decade we have been advancing the #4 Shaft project at the Lucky Friday. We will complete this project this year, positioning the mine to operate for decades. We have elected to spend capital on San Sebastian (Durango, Mexico) and Casa Berardi (La Sarre, Quebec, Canada) to start a new mine and increase production, respectively. And we are spending money on new techniques, new equipment and innovations to our operations. Our insistence is on developing for the future, and our persistence in doing so is in contrast to many companies that are reducing investment and shrinking production"

Jun 1, 2016

"Tell us how you got involved in mining and about your career path.My dad was a coal miner and my uncle was a metallurgist, so when I enrolled at Penn State’s New Kensington Campus, I chose the College of Earth and Mineral Sciences — exact majors didn’t get picked till the end of your sophomore year. Penn State New Ken had an associate degree in mining program and one of the guys in my carpool was going to take Mining 30 in the evening and the other guy (mechanical engineer) was also able to take an evening class. I didn’t want to break up the carpool, so I took Mining 30, complete with essay tests. I could write, so I did well, and the professor said I should go into mining engineering. Fast forward to the end of the next term at University Park, and I realized there wasn’t enough chemistry in mining. Switching to metallurgy would have meant another term at that point, so Dr. Lovell, my advisor, trotted me down the hall and to the next building and said I was a mineral processor. That stuck. I was a summer student at U.S. Steel Research between my junior and senior year and they paid for my master’s degree — all about clay and macerals in coal flotation. During that time, the steel industry tanked, and I thought a Ph.D. would be a good idea — I could always teach at the university level if I had those credentials. The Electric Power Research Institute had a Coal Cleaning Test Facility in Homer City, PA, and I conducted my Ph.D. research on rate and residence time in conventional coal froth flotation cells there and at a local cleaning plant. I went to work at the test facility in 1987 (later CQ Inc.) and stayed there until I started PrepTech Inc. in 1997. PrepTech offers some consulting services for coal cleaning plants and sells mineral processing equipment, mostly to coal companies. I can’t believe it’s been 21 years.And what about your SME career?Of course, I was a student SME member at Penn State. We used many of the SME books in class, so who wouldn’t want the student discount? While in Homer City, I became involved with the Appalachian Plateau Subsection of the Pittsburgh Section. We’d hold quarterly meetings with interesting speakers and had good attendance. I was the secretary. I’m still the secretary and also get the bank statements. We’ll need to close that out some time, but I guess I’ve been hoping for resurgence in the Indiana/Cambria/ Somerset area."

Jan 3, 2018

By Meghan M. Murphy, Derek Penrice

The Downtown Rail Extension (DTX) is principal element of the planned second phase of the Transbay Joint Powers Authority’s (TJPA) Transbay Program. When complete, this regionally critical project will connect Caltrain’s regional rail system and the California High-Speed Rail Authority’s statewide system to the Salesforce Transit Center in downtown San Francisco via a 1.3-mile tunnel. Studied since the 1970s, the DTX has now received environmental clearance, and key stakeholders are aligned on the project’s configuration and its expedited delivery. This paper describes efforts to optimize the DTX configuration and develop an informed project delivery strategy that incorporates construction industry feedback on project phasing, contract packaging, and procurement methods that accomplish the project’s budget goals.

Jun 13, 2021

By Yuting Xue, Mark Van Dyke, Zoheir Khademian

Borehole scoping has been widely used in the U.S. underground coal mines as a method for geologic mapping and stability analysis because it is very useful for identifying rock types, voids, fractures, and formation boundaries through the direct observation of the borehole wall. An image stitching technique was proposed to generate panoramic borehole images from side-view borescopes in a previous study. However, the generation of panoramic borehole images can be affected by the borehole condition because the image stitching process highly depends on the key point detection and matching. The presence of dust and water could have a significant influence on the detection of key points. In this study, the influence of borehole conditions on panoramic borehole images was studied from the success of image stitching and the visibility of geologic features and lithology changes. Borehole videos recorded at different times, when the same borehole was freshly drilled, freshly washed with water and 12 days after washing, were processed with the proposed technique. The comparison of the stitched images shows that the presence of dust has minimal influence on the image stitching process but shows significant negative effects on the visualization of geologic feature and lithology change. In addition, the presence of water can significantly hinder the image stitching process, which in turn helps in identifying lithology change. Borehole scoping aids in identifying and mitigating hazardous conditions in underground mines, and this study provides preliminary inputs into identifying optimum borehole conditions for geologic mapping with panoramic borehole images.

Feb 1, 2025

By T. W. Camm, J. C. Johnson, S. D. Rosenthal

"Most engineers are bright, hard-working, reliable and prefer to avoid conflict. An engineering curriculum tends to self-select these characteristics. By most standards, you would expect workers exhibiting these traits to require minimal supervision. But, is this true? Is this how most current engineering managers lead? Looking at some current theories on leadership combined with personal anecdotes, this article will look at some common misconceptions about leading engineers.Engineers are different. There, it has been said. From cartoons to movies to television shows and more, there is a reason stereotypes of engineers resonate. Yes, you can find a lot of individual variation among specific engineers that you may know, but they do not detract from some of the overarching commonalities that engineers are known for.Clash of culturesWhat distinguishes a professional? Raelin (1985), in his book Clash of Cultures, describes professionals as having superior intellectual training, maintaining their own standards of excellence and being supported by associations that maintain the quality of the profession. Engineers obviously fit all three of these ideas: an engineering degree is still regarded as one of the most difficult to attain. Standards are maintained both through peer review and in academia, through ABET accreditation and through professional associations like SME to promote the discipline and foster technical growth.Six characteristics representing professional status are described by Raelin (1985, p. 9):• Expertise — prolonged specialized training in a body of abstract knowledge.• Autonomy — the freedom to choose the means to solve a problem.• Commitment — primary interest is in pursuing the practice of one’s own chosen specialty.• Identification — identifying with the profession and with fellow professionals, both through formal associations and through peers external to the organization.• Ethics — providing service without concern for oneself or without becoming emotionally involved with the client.• Standards — committed to help in policing the conduct of fellow professionals."

Jan 1, 2018

By J. Gauntt

Calcium carbonate is one of the most widely used industrial minerals in applications like cement, lime, agriculture, power plant fluegas desulfurization (FGD) and construction aggregates. Most applications are generally high-volume and low value ($9/t or $10/st) or less free-on-board (f.o.b.) mine site) uses of this material. Specialty uses of ground calcium carbonate (GCC) are typically referred to as ?performance mineral? or ?extender and ?ller? applications. Primary specialty markets for GCC include paper and plastics as well as a number of construction applications including joint compounds, carpet backing, paint, and adhesives, caulks and sealants (ACS). Other important specialty applications for GCC include rubber, food and personal care products. A new and growing application for GCC is in nonwoven fabrics, where this mineral replaces a small percentage of the polymer. Typical specialty applications for GCC are color sensitive and require extremely white/bright materials. Although deposits of limestone are located in most states, high brightness resources are relatively rare and controlled by a limited group of suppliers.

By William Gleason

"The Colorado School of Mines has used the Edgar Mine in Idaho Springs as an experimental mine to teach students since 1921. Since the school acquired the former gold, silver, lead and zinc mine, countless students have received hands-on engineering lessons on their way to earning mining engineering degrees. On Dec. 14, the House Subcommittee on Energy and Mineral Resources held a historic field hearing about the future of mining education in the United States in a classroom about 300 m (1,000 ft) inside the Edgar Mine. Representatives Doug Lamborn (R-CO), Rob Bishop (R-UT), Cresent Hardy (R-NV) and Ed Perlmutter (D-CO) were on hand for the first ever congressional hearing held in a mine where they heard testimony supporting the Mining School Enhancement Act, which was introduced to Congress by Hardy and Perlmutter on Oct. 9, 2015. The act, which is part of a larger mining development and reclamation reform package, seeks to address the absence of a viable pipeline necessary to replenish current faculty vacancies in United States Mining Schools. “What better place to hold a hearing to discuss the need for future mining engineering experts,” Subcommittee Chair Lamborn said in his opening statement. “It is a need felt by industry, states, the federal government as well as nonprofits.” The Mining School Enhancement Act would redirect millions of dollars in fees that are being collected from active mining operations to fund the research and educational programs at engineering schools with mining programs. Those fees now are being used in the form of grants awarded by the Surface Mining Control and Reclamation Act of 1977 (SMRCA)."

Jan 1, 2015

By Danqing Gao, Brijes Mishra

Heterogeneity in rock formation affects both rock behavior and strength. Spatial variance of rock properties is an important characteristic of rock that addresses the heterogeneity of mechanical and physical properties and their effects on underground mining. Assessing spatial variance can be useful for locating potential difficult grounds and for performing reliability analysis in the mining support system. This study presents a spatially correlated, random model to investigate the influence of rock heterogeneity on rock strength and failure propagation. A random field database with specific spatial correlation was created for each physical-mechanical property using laboratory data and the extreme value stochastic model in MATLAB. Based on the improved microscale random model, we considered one three-dimensional numerical model to study a mine operating in the Pittsburgh seam. The influence of random field data on entry roof was investigated. The realistic random field database added two scale-measured parameters from horizontal and vertical directions to control the spatial correlation length. A number of cutting sequences were also considered in order to identify the effect of spatial variance on roof behavior. The results show that spatial variance provides an accurate prediction of erratic roof falls in coal mines.

By George Saratsis, George Exadaktylos

In the marbel industry, ore reserves refer to the produced tonnage of orthogonal prismatic, defect-free blocks of commercial sizes and of marketable aesthetical quality. On the contrary, in the mining sector, ore reserves refer to the tonnage of ore with grade above some cut-off value. While in the mining sector ore reserves are reported according to existing standard guidelines, the marble industry has no standardmethod. The purpose of this paper is to present a method to estimate white marble reserves using drill coring or borehole wall logging and limited joint mapping on exposed marble surfaces. Data pertaining to fracture orientation, fracture frequency, size, and whiteness were collected. The primary phase of marble characterization is followed by the discretization of the orebody into a three-dimensional array of orthogonal prismatic blocks, where the marble whiteness and fracture intensity are attribute values. Both these variables are considered to obey continuous and not discrete probability distributions. The discretization is performed using computer aided design and the Block Kriging techniques. An outline to improve the description of a given marble ore deposit at the exploration stage is presented for the prediction of marble block size distribution from joint count measurements along diamond drill cores. An example case of a white dolomitic marble quarry is used to demonstrate these methods.

May 27, 2020

By M. D. Loy

In addition to products available from private vendors, many useful programs are developed at universities - in fact, many of these programs led the way to commercial development. Other projects are assigned to consultants with backgrounds in system design and mining. Both types of development have led to programs that can be acquired for the cost of a tape or disk. This paper highlights several underground mining packages. These programs consist of: ? USBM model-developed by the United States Bureau of nines. ? PSU model-developed by Pennsylvania State University. ? VPI model-developed by Virginia Polytechnical Institute and State University. ? NUS model-developed by NUS Corp.

Jan 1, 1987

By Danny Chan, Shahram Tafazoli, Nicholas Himmelman, Edmond Chow

"While wearable technology has been garnering attention in the consumer market, enterprise and industry have just begun exploring its potential applications. Since February 2014, Motion Metrics International has been working in collaboration with Vandrico Solutions Inc. to apply wearable technology to improve productivity and safety in the mining industry.This article discusses the value proposition of using wearable technology to deliver critical notifications in mining. The advantages and disadvantages of various form factors are explored. The challenges, both specific to mining and in general to wearable technology, are defined. Finally, the concept of MetricsGear, the first wearable technology platform developed for mining by Motion Metrics International in collaboration with Vandrico Solutions Inc., is described. MetricsGear is designed to notify the user with minimal distraction to keep the user focused on his or her primary task and aware of mission-critical events. This focus and awareness allows the user to work more efficiently and safely. The mining process consists of a series of intricate stages, where certain events or conditions in one stage can have a huge impact on other stages. The notification of these critical events or conditions is vital for ensuring the overall efficiency of the mining process. Critical notifications can be classified as two types: timecritical events and contextual information. Time-critical events are situations where a timely response from a responder can have a significant impact on seizing an opportunity or mitigating cost. Some human-computer interaction (HCI) experts classify notification types based on the interruption, reaction and comprehension (IRC) framework. Time-critical events are classified to have high interruption, high reaction and low comprehension due to their urgency. The responder should have just enough information to identify the crisis and react as soon as possible (Chow, 2014). For example, when a tooth is lost during shovel operation, it is necessary to recover the missing tooth before it jams the primary crusher. The consequence of missing this critical time period is a jammed crusher that can cause the mine to be out of production until the jammed tooth is extracted (Baumann, 2013). In this case, the responder only needs to see an image to confirm if the tooth is missing and information to identify which equipment and when the tooth went missing (Fig. 1)."

Jan 1, 2014