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By M. Frenzel, D. Ebert, K. Bachmann, A. D. Renno, R. Möckel, J. Gutzmer, J. Krause

With the increasing demand for metalliferous and mineral raw materials and the consequent depletion of the global natural resource base, the possible utilization of secondary raw material sources is receiving more and more attention. In the present study, we present results from a detailed vanadium deportment study of three basic oxygen furnace slag (BOS) samples known to containing elevated bulk concentrations of vanadium. Complementary analytical methods that were used to quantify the abundance and composition of V-containing phases include SEM-based automated mineralogy, X-ray fluorescence analysis, and X-ray powder diffraction as well as electron probe microanalysis. The vanadium deportment was quantified using Monte-Carlo simulations of the data obtained from automated mineralogy and electron microprobe analysis. The total V concentrations identified by XRF are between 1.7 and 2.2 wt.% V. The most important hosts of vanadium are larnite-, brownmillerite- and portlandite-solid solutions. In two samples Ca carbonates also significantly contribute to the V deportment, while wuestite, lime, and native iron do not contribute significantly to the vanadium deportment. A thorough consistency check identifies considerable uncertainties in the density of the V-bearing phases as the most likely reason to explain remaining discrepancies between measured and calculated V values.

Oct 14, 2023

By M. Westendorf, T. Banerjee, S. Kaushik, D. Tinney

"Cyclones are one of the most extensively used pieces of equipment within the mineral processing industry because of their simplistic operating and maintenance philosophies. They are commonly used as classifiers within the comminution circuit to control the grinding product particle size for satisfactory performance of downstream operations.Cyclones are a key contributor to the effective operation of the plant and have a significant impact on the mineral processing plant operations. If the cyclones are not performing as they should, the results are often a combination of lost recovery, grade, capacity and reduced throughput. Similarly, an inefficient cyclone operation may also lead to low or high recirculating loads that impact the efficiency of the comminution circuit. This highlights the importance of having proper stability in cyclone operation while implementing any plant-wide optimization strategy.One of the key challenges in cyclone operation is that cyclones are highly sensitive to changes in operating conditions and are affected by process fluctuations such as feed pressure, solids concentration and flow rates. Fluctuations in cyclone feed characteristics lead to unstable cyclone performance which affects mineral liberation. For such an impactful unit operation, cyclones have historically been under-instrumented in an otherwise highly instrumented process plant. Traditionally, mill operators have relied on visual observations of the apex discharge to determine the operating state of the cyclones. Visual cues corresponding to the different cyclone operating conditions have been discussed by Neesse et al. (2004) as shown in Fig. 1."

Jan 1, 2014

Computer programs commonly used to simulate mining operations generally require a fair amount of data. The common data input methods have been by either creating an ASCII data file or answering numerous questions during the data input phase. Both methods of data entry are tedious, time consuming, and inflexible. A screen handling system has been developed to drive FORTRAN-77 application software for the MS-DOS environment. The system utilizes keyboard functions with an aid of extended ANSI codes. It also allows a multi-view input data entries.

Jan 1, 1990

By Milton Gomez, Nico Sutmoller

Low-density cellular concrete (LDCC) was first introduced to the market in the early 1900s and since then has made continuous technological advances. There are two primary types of LDCC: permeable and non-permeable. Both types of cellular concrete offer advantages in different types of geotechnical engineering applications. Because of its unique characteristics of low density, high compressive strength, and high fluidity during placement, LDCC offers an effective solution for a wide variety of engineering applications, and in many cases provides a more cost-effective, labor saving alternative to traditional fill materials. This paper will review the history, characteristics, and technological advances of LDCC, highlighting multiple real-world case studies that showcase the high-performance capabilities of both permeable and non-permeable LDCC.

Dec 1, 2022

By R. L. Derick

The Orchard Valley Mine, a large underground coal mine located in western Colorado, experienced a major mine fire during an idled Sunday on June 1, 1986. This mine had extensive problems with spontaneous combustion near the coal outcrop. Spontaneous combustion has been determined to be the probable cause of that fire. Preparing for a mine emergency was an on-going task. Once the emergency occurred, much of the preparation work was implemented and aided in controlling the situation. Later, the successes and shortfalls that arose from that emergency were analyzed for future course of action. This paper summarizes the activity that led up to the major fire, the handling of that emergency, the lessons learned, and the changes implemented.

Jan 1, 1993

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 S. K. Samal, B. Mishra, M. K. Mohanty, S. C. Mishra

Steelmaking industries consume the majority of chromium and manganese ferroalloys to impart several properties in steel and also for other purposes. The quality of ore governs the process kinetics as well as the process economy of the ferroalloy industry. The present study demonstrates the thermal transformation behavior of chromite and manganese ores with varying compositions. Simultaneous thermal analysis (DTA/TG) is employed for such ore samples where the transformation of mineral phases is correlated with the thermogram characteristics and quantified. Phase, microstructure, and compositional analysis results of individual ores corroborated with thermal analysis are in good agreement. Chromite samples are ferruginous with goethite and gibbsite contents, whereas manganese ores vary in composition and also exhibit multiple and/or overlapping transformations.

Jan 21, 2021

By A. Noble

Linear circuit analysis (LCA) is a fundamental tool which has been used to evaluate mineral separation circuits during the preliminary design phase. Traditionally, the LCA methodology uses the analytic circuit solution to determine the relative slope of the circuit?s partition curve. This value is then used as an indicative performance measure suitable for the comparison and ranking of alternative circuit configurations. Unfortunately, the partition curve slope only reflects the separation potential of middling material. In most mineral systems, this material represents a small portion of the initial feed (due to liberation) as well as a small portion of the revenue potential (due to the incremental value). Respecting these limitations, the authors have developed new separation performance indicators which may be derived from the analytical circuit solution and used in LCA problems. These indicators inherently reflect the separation potential of pure material, providing a better indication of lost revenue due to misplaced material. The complete methodology has been integrated with prior software to produce the Heuristic Optimizer for Resource Separation Economics (HORSE).

Feb 23, 2014

By Greg J. Hasenfus, Allison M. Haines, Joshua M. Silvis

The floodable volume of longwall gob can be of great importance in developing accurate coal mine operation plans, particularly for mine water management and environmental control strategies. Given the inaccessibility and difficulty in direct measurement of gob characteristics following gob recompression, hydrologic, geomechanical, and spatial data and principles were used to solve for the porosity and height of the residual gob using a mathematical model framework and bulking-based techniques. Based on this approach, gob porosity of Appalachian longwalls appears to be tighter than previously reported, ranging between 4.99 and 14.31%. Residual gob height, as normalized with respect to mine extraction height, ranges between 1.90 and 2.45. A novel, bedding-based bulking approach is ampliative with respect to existing roof caving and bulking fundamentals, as it has greater explanatory value compared with the traditional, lithologic-based bulking application. The efficacy of using the residual gob characteristics determined by the mathematical model and bedding-based bulking is examined using a causal comparative method, whereby time series prediction of historical groundwater rebound is compared with observed mine pool elevation data. Prediction accuracy is significantly improved using a prototype model to calculate void volume of longwall gob, specifically, the dependence of porosity of the gob material upon the longwall width to overburden depth ratio for movement basins of subcritical and critical panel widths. The potential implication of these findings toward hydrologic, geomechanical, and ventilation studies of longwall gob could be significant.

Aug 13, 2021

By Tim M. Benson, Adam L. Lamanna, Carolina Martinez-Gutierrez, Mark J. Stephani

The Lower Concourse C Extension (LCE) 108-in Storm Sewer consists of a 2,797-foot long, 27 to 55-foot deep, 108-in I.D. storm sewer tunnel. Situated beneath active taxiways and a terminal apron at Hare International Airport (D), the tunnel diverts ows from existing storm sewers located within the footprint of a future satellite concourse. The project was delivered via Construction Manager at Risk (CMAR) as part of Chicago Department of Aviation’s (CDA) ongoing O’Hare 21 Capital Program. This paper presents project details, multiple stakeholder coordination, subsurface risks and challenges, TBM performance, and impacts to existing infrastructure.

Jun 23, 2024

By S. K. Kawatra

It is common in coal-cleaning operations to produce a fine waste stream which contains a considerable amount of coal, but which is not economical to recover both because it is mixed with large amounts of difficult-to-remove clay slimes, and because the fines are often heavily oxidized. Conventional froth flotation machines cannot produce an acceptable product from such material in a single stage of flotation, and even flotation columns often have difficulty cleaning this type of feed. A new type of flotation column was designed specifically to deal with these problems, and was installed and tested in a coal-cleaning plant in Ohio. The feed coal contained 39.8% ash as fine clay, and 2.83% total sulfur, and was 80% passing 176 micrometers. The coal was a thickener product which had oxidized for some time, and was very difficult to float. However, using the new column it was possible to recover up to 85% of the calorific value in a product containing less than 11% ash, and up to 60% of the calorific value in a product of less that 8% ash. The bulk of the pyritic sulfur was rejected from the coal as well. Multistage flotation tests showed that the flotation column was able, in a single stage, to produce the best froth flotation product that it was possible to recover from this coal.

Jan 1, 1994

By Juan J. Monsalve, AMAN SONI, ALEX PFREUNDSCHUH, Nino Ripepi

Ground control failures are one of the main causes of accidents in the underground stone mining industry. Some of the fundamental tools for rockfall hazard identification are related to rock mass characterization and geotechnical discontinuity mapping. Recent technological advances in these methods are related to remote sensing techniques and pointcloud processing software for automated discontinuity mapping. Remote sensing techniques, such as LiDAR and photogrammetry, generate multimillion-point clouds with millimetric precision, capturing the structure of the rock mass. The automated point-cloud processing tools offer alternative algorithm-based methods to characterize and map these discontinuities. However, their applicability is constrained by multiple factors, such as site-specific conditions of the rock mass and the parameters used within the mapping algorithms. This paper evaluates the performance of automated discontinuity extraction software compared with manual virtual discontinuity mapping. Sampling windows from laser-scanned sections in an underground limestone mine are defined and mapped using the Discontinuity Set Extractor (DSE) opensource software. Results from the virtual discontinuity software are compared with manually extracted fractures from I-Site based on reviewing orientation, trace length, spacing, number of extracted discontinuities, and processing time.

Software exhibitors at MINExpo will feature the newest, the best, the most comprehensive computer-based tools available to get minerals from the ground to the market. From the ?cloud? to the pit, the variety that will be featured is almost limitless ? a digital tool for every phase of the mining lifecycle. Blue Sky Network SkyRouter brings the Blue Sky Network to the cloud. Using its interactive Web portal, SkyRouter, with detailed mapping and integration with Google Earth, the Blue Sky Network links enterprises to personnel and assets anywhere on earth through Iridium satellites. The cloud-based solution is designed to support connectivity with remotely dispersed mobile assets, including Blue Sky?s dual-mode GSM and Iridium tracking and communications services. This enables seamless connectivity with assets in problematic cellular reception areas, where only 10 percent of the Earth is covered, and in remote locations.

Jan 1, 2012

By Osvaldo A. Bascur

Intelligent systems (IS) technologies have received much attention in a wide range of process engineering applications including process operations. With the revolutionary progress in information and computer technologies applying the latest technologies in metallurgical complexes has become a serious challenge to both management and technical teams. Objects and components are changing the way everyone relates to their computer and networks. Goals of real time performance monitoring includes maximizing the profitability by maximizing production, improving efficiency, attending product quality, costs, maintenance, environmental and safety regulations. Designers must consider the greatly expanded desktop computing, Microsoft object technology, Internet and how to build these systems. This paper discusses some opportunities and challenges using objects, components in designing applications and integrating intelligent systems tools. Two examples using performance equations and IS technologies applied to mineral processing are presented.

Jan 1, 1997

By Tyler Luxner

Stillwater Mining Co. (SMC) is the largest primary producer of platinum and palladium in North America. SMC operates two underground mines in south central Montana, along the 45-km (28-mile) platinum/palladium J-M Reef in the Stillwater Complex. The Stillwater Mine exploits 9.6 km (6 miles) of deposit strike length and East Boulder Mine exploits 4 km (2.5 miles) of deposit length. The two mines are 20.4 km (12.7 miles) apart with SMC controlling a considerable length along the entire J-M Reef trace. Production at the Stillwater Mine began in 1986 and in 1988 the first tunnel boring machine (TBM) was commissioned, becoming an integral part of mine development at SMC. TBMs have been used for developing production footwall laterals (FWL) to access new mining blocks at the Stillwater Mine, as well as boring twin crosscut ac-cess tunnels at the East Boulder. Two TBM development expansion projects are currently in progress: the Graham Creek project at the East Boulder Mine, which will extend footwall lateral development 2,591 m (8,500 ft) to the west, and the Blitz project, where a TBM will be commissioned to extend east out of the Stillwater Mine to 3,658 m (12,000 ft) beyond the current production mining front. General strike and dip of the Reef is west to east and to the north, respectively.

Jan 1, 2012

By M. Paul

"INTRODUCTION In 1990, the uranium production of SDAG Wismut in East Germany was stopped. 45 years of inconsiderate destructive exploitation had scarred both landscape and nature. With the “Wismut law” which came into force in December 1991, the Federal Republic took responsibility of the remediation of the legacies from former uranium ore mining and milling in Saxony and Thuringia. A unique opportunity turned out in order to remove environmental damage, to enhance the life quality of the local population, to shape new landscapes and to advance the economic restart. (1) The results of nearly 25 years of remediation activity are evidence that this opportunity was used at all former SDAG (Sowjetisch-Deutsche Aktien-gesellschaft) Wismut sites. The reference project “Wismut“ has evolved into a joint project of all parties involved and radiates beyond the affected regions. This is particularly reflected by the Know-how transfer starting from Wismut and the increasing activities for third parties abroad.WATER MANAGEMENT AT WISMUT REHABILITATION Within the Wismut project, water management and conventional technical water treatment are by far the most cost-intensive long-term tasks of the remediation programme. Over the medium term, there is no viable alternative to the operation of active systems to catch and treat contaminated mine waters at the Ronneburg, Schlema, Königstein, Pöhla, Seelingstädt and Helmsdorf sites. Based on the status quo, this paper outlines the key issues of the Wismut GmbH water management strategy over the medium and long term. It is focused primarily on achieving protection goals for potentially impacted water bodies in the surroundings of Wismut sites and on optimising associated remediation expenditures as well as on creating the prerequisites for achieving low post-remedial care and maintenance or walk-away system status over the long term. (2) The applied mining practices during the active SDAG Wismut period have not been up to the high standards of modern mining operations and their requirement to leave former production premises and deposited residues in a condition that was not only physically but also chemically stable. Rather the emission of mine and seepage waters laden with high acidity, metal and salt content is a frequent corollary and difficult legacy of historic mining and processing operations (4, 5). As a consequence, the control or mitigation, respectively, of environmental impacts associated with contaminated mine waters ties up enormous public resources worldwide (6, 7)."

Jan 1, 2016

By S. Klein, M. McLeod, S. Gambino, K. Johnson, E. O’Hara

The Mokelumne Aqueducts Resiliency Project (MARP) involves construction of a 16.5-mile tunnel across the Sacramento-San Joaquin Delta (Delta) to replace the existing surface aqueduct pipelines with more resilient conveyance. The tunnel will be bored in Pleistocene-age alluvium at elevations between 100 to 10 feet below mean sea level. At this depth ground conditions are signicantly stiffer and denser than surcial soils and will mitigate potential seismic harards related to liquefaction ground shaking and cooding that could arise from potentially damaged levees. The heterogeneous soil deposits at tunnel depth consist of interbedded layers of stiff to very stiff clay and silt, and dense to very dense clean sand and silty sand.

Jun 23, 2024

By S. A. Smith-Hamm, E. A. Sarver, A. S. Cox

Appalachia is an increasing concern, as unnaturally high TDS and/or associated specific conductivity (SC) may contribute to deteriorated stream ecosystem health. The aim of this preliminary study was to explore the efficacy of accelerated leaching as a means of minimizing long-term TDS/SC generation by problematic overburden materials. Five spoil samples were collected and leached using simulated rainwater solutions under ambient and acidified pH conditions. SC and pH were monitored during each leach cycle, and inductively coupled plasma-mass spectroscopy (ICP-MS) was used to determine how leaching conditions affected the release of specific ions. This paper highlights the results of both jar and column leaching tests. Among the most significant findings was that for certain spoil materials, the SC in the leach column effluent was effectively reduced when the spoil was first leached with acidic rainwater followed by ambient rainwater, as opposed to leaching with ambient rainwater alone. This suggests that accelerated leaching might aid in the long-term stabilization of some materials.

Jan 1, 2015

By G. M. Wilemon

The U.S. Bureau of Mines has conducted investigations on extracting phosphate values from wastes generated during the mining and beneficiation of phosphate matrix. These wastes may contain up to one third of the phosphate originally present in untreated ore. Samples of wastes were air-dried and leached using 93 pct sulfuric acid in the presence of methanol. Evidence for the formation of a calcium sulfate hemihydrate coating that hinders complete dissolution of phosphate is presented. Solid-liquid separations were enhanced when flocculation was effected using poly(ethylene oxide) (PEO) in conjunction with hydroxypropyl cellulose (HPC) or hydroxyethyl cellulose (HEC. A conceptual flowsheet for a proposed process using an acid-alcohol leaching technique is presented.

Jan 1, 1990

By S. A. Pierce

Heightened environmental consciousness has resulted in the development of various international accords dealing with natural resource management. This international awareness is now being translated into regional and local initiatives that proactively implement collaborative environmental management programs. One such program was recently initiated in northern Chile in recognition of the interconnection of Andean salars. Cooperative efforts between industry, governmental agencies and academic professionals have resulted in the implementation of simultaneous environmental monitoring of flora and fauna in the salars of northern Chile. This coordinated effort is leading to an improved understanding of the migratory patterns of South American fauna, as well as improved access to an expanded database for the multiple user groups associated with the Andean salars. The El Abra Mine is actively participating in these coordinated monitoring efforts.

Jan 1, 1999