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By M. Mathiba

High CO2 fluxes associated with reclaimed coal mine spoils pose an environmental hazard where such sites are used for building. CO2 concentrations in excess of 25% have been reported in homes constructed on or down gradient of such spoils. The objective of this study was to investigate the effect of a mitigation trench used at one mine site on CO2 fluxes across the trench using chamber?based trace gas measurement. LI8100 automated CO2 flux system was used to measure CO2 fluxes from 32 sample points located across a deep mitigation trench on June 8 and 9. The maximum recorded fluxes were 7.29 and 8.18 µmol/m2/s, with averages of 4.15 and 5.50 µmol/m2/s, up and down-dip respectively. These preliminary results show CO2 flux is higher up-hill than down-hill at 95% significant level. This work shows that flux measurement can be used to investigate CO2 migration on reclaimed mine land. Further work is necessary to allow geostatistical modeling of the spatial variability of CO2 fluxes over reclaimed coal mine spoils. Knowledge gained would assist mining practitioners and regulators in reclamation planning for envisaged post-mining land uses.

Jan 1, 2010

By Kefton H. Teague

Olivine was first described and named by Warner in 1790. It is an olive green to greenish gray colored magnesium-iron silicate containing a mixture, in solid solution, of fosterite (Mg2SiO4) and fayalite (Fe2SiO4). Ratios between fosterite and fayalite in olivine are somewhat variable, but in general olivine contains at least 85% fosterite. Specific gravity is variable also, depending on the ratios of fosterite to fayalite. As a rule it is in the 3.2 - 3.4 range. All commercial olivine is obtained from the rock dunite, the most basic member of the peridotite group. Dunites, in addition to being composed primarily of olivine, generally contain assessory pyroxenes and spinels (chromite and magnetite). Dunites', when altered by hydrothermal solutions or metamorphism, often contain alteration minerals such as talc, serpentine, chlorite, vermiculite and amphiboles. In the 1930's and 40's considerable research was conducted on olivine for use as a refractory, plant food raw material, magnesium source for metal, and a source for magnesium chemicals. This research met with only limited success.

Jan 1, 1977

By Joel Lööw, Jan Johansson, Lena Abrahamsson

Industry 4.0 offers new possibilities to combine increased productivity with stimulating workplaces in a good work environment. Used correctly, digitalization can create attractive jobs in safe control room environments, which provide space for the employee’s full expertise and creativity. This is true also for the mining industry. But, to succeed, it is important to analyze the development from a worker’s perspective. What will happen to their work? What skills will be needed in the mine of tomorrow? We must also consider the risks, such as privacy issues, increased stress, and work-life boundaries. These questions must be understood if we are to create workplaces that can attract a young and diverse workforce to tomorrow’s mining industry. In this article, we try to illustrate what the new technology can mean for the individual miners. We formulate the notion of Mining 4.0 (Industry 4.0 in the mining industry), where we try to create an image of how the future might look from a miner’s perspective and how mining companies may navigate their way to a future that works for all miners. To illustrate the range of possible outcomes, we formulate two scenarios: one utopian and one dystopic. At the end of our article, we bring forward six recommendations that can be considered a beginning of a road map for the human side of Mining 4.0.

By Joel Lööw, Jan Johansson, Lena Abrahamsson

Industry 4.0 offers new possibilities to combine increased productivity with stimulating workplaces in a good work environment. Used correctly, digitalization can create attractive jobs in safe control room environments, which provide space for the employee’s full expertise and creativity. This is true also for the mining industry. But, to succeed, it is important to analyze the development from a worker’s perspective. What will happen to their work? What skills will be needed in the mine of tomorrow? We must also consider the risks, such as privacy issues, increased stress, and work-life boundaries. These questions must be understood if we are to create workplaces that can attract a young and diverse workforce to tomorrow’s mining industry. In this article, we try to illustrate what the new technology can mean for the individual miners. We formulate the notion of Mining 4.0 (Industry 4.0 in the mining industry), where we try to create an image of how the future might look from a miner’s perspective and how mining companies may navigate their way to a future that works for all miners. To illustrate the range of possible outcomes, we formulate two scenarios: one utopian and one dystopic. At the end of our article, we bring forward six recommendations that can be considered a beginning of a road map for the human side of Mining 4.0.

By Patrick Scott, Germán Schmeda, Morgan Mullins, Liam Knudsen, Bradley S. Van Gosen, Carma A. San Juan, Nicholas A. Karl, Jeffrey L. Mauk, Clayton Forbush

The objective of the US Geological Survey’s mineral deposit database project (USMIN) is to develop a comprehensive twentyfirst century geospatial database that is the authoritative source of the most important mines, mineral deposits, and mineral districts of the US. Since May 2017, the project has focused on critical minerals. Data for critical minerals that are produced as products are relatively robust, whereas data for critical minerals that may be recovered as byproducts are commonly of much poorer quality. Similarly, more is known about critical minerals that occur in conventional deposits than where those critical minerals occur in unconventional deposits. For example, rare earth elements occur principally in deposits hosted by alkaline igneous rocks, but there is potential for their production from phosphate rock mining, which is less documented. Lithium (Li) has been recovered from pegmatites and brines, but other Li-bearing deposit types have been delineated that may go into production. Cobalt may be produced as a byproduct or coproduct from a wide range ofmineral deposit types, whereas rheniumis a byproduct of copper ore. Significant opportunities for research exist that could help identify new sources of critical minerals, and may also help increase production and recovery from existing sources.

Feb 8, 2021

By Georgene Renner, Chee Theng, William Gleason

"More than 6,300 people attended SME’s 2016 Annual Conference & Expo in Phoenix, AZ and many of them made the trip to the conference to take part in the excellent technical sessions that are presented on a yearly basis by the Society.Holding true to form, this year’s conference was full of options. In fact, this year there were 121 technical sessions and 751 presentations to chose from. The following is a sample of some of the technical sessions as seen through the eyes of the editors of Mining Engineering and SME technical papers.SME Sections Sharing Success: Changing thePublic Perception of MiningThis session was a workshop on how several local sections were effective in getting the message out to their communities and schools about the value of the extractive minerals industry. Several sections shared their outreach successes, including the Mining in Society merit badge activities by the Minnesota Section by Julie Lucas and SME’s participation in the World Scout Jamboree in Japan by Frank McAllister.Dan Alexander highlighted activities by the Pittsburgh Section, such as preparing minerals kits and pamphlets for elementary school classes and regional science fairs. The West Virginia University Student Chapter used the kits as handouts at their local gem and mineral show. School speakers in full mining gear were especially interesting to the young children.Other speakers were Michael Linn, Paradise Valley Unified School District — Business and School Partnerships; and Greg Kruse, Central Wyoming Section of SME — What makes a successful section?Engineering Competency ModelAmerican Association of Engineering Societies and the U.S. Department of Labor, with a grant from the United Engineering Foundation, developed a guide to the set of skills necessary for success in the engineering community -- Knowledge – Skills – Abilities — needed for all disciplines.Various engineering societies are now writing the Tier 5 occupation-specific requirements. The Competency Committee is charged to write concise and discipline-specific mining engineering, mineral processing engineering, geological engineering, and geophysical engineering by Sept. 30, 2017."

May 1, 2016

By D. J. A. Chambers, J. M. Wempen, K. D. Koper, M. K. McCarter, K. L. Pankow

"The EarthScope Transportable Array (TA) of broadband seismometers (www.usarray.org) was deployed across southwest Wyoming from November 2007 through May 2009. During this time period the Array Network Facility (ANF, anf.ucsd.edu) detected and located a total of six seismic events near the trona-mining district. This lack of seismicity is atypical compared to coal mines employing similar mining methods. In this study, eighteen months of continuous seismic data from several nearby TA stations are reexamined using conventional and correlation-based methods to detect seismic events. Waveform cluster analysis and epicentral locations are used to discriminate between mining induced seismicity (MIS) and seismic energy generated from surface blasts at nearby coal mines. The locations and magnitudes of the 143 newly detected MIS events are compared to regional subsidence as measured by Differential Interferometric Synthetic Aperture Radar (DInSAR). INTRODUCTION An abundance of natural resources and a favorable political climate have made southwest Wyoming home to multiple large mining operations. Among these operations are five underground trona mines located approximately 50 km west of Rock Springs, Wyoming. The trona mines employ room and pillar, longwall, and solution mining methods over an area roughly 900 km2, and produce a sizable portion of the world’s soda ash (Brown 1995). Historically, in the Rock Springs mining district, several relatively large magnitude seismic events have occurred. These events are thought to have been related to mining activity and have caused notable subsidence (Case 1997). The largest event in the region recorded by seismometers, ML 5.1, has been confirmed as the 1995 Solvay Trona Mine collapse (Pechmann et al. 1995). In addition, blasting at surface coal mines near Rock Springs produces significant amounts of seismicity; approximately 50% of all daytime seismic events in the Mountain time zone from 2007 to 2009 locate near an active surface mine in this region (Astiz et al. 2014). Much of the current research related to surface subsidence and induced seismicity focuses on wastewater impoundment (Ellsworth 2013) and hydraulic fracturing. The observable seismicity in geological injection environments is widely variable and McGarr (2014) has argued that, in such environments, the maximum amount of seismic energy that can be released is proportional to the injected volumes. Like injection environments, in extraction (mining) environments seismicity is highly variable depending on many geological and operational variables (Boltz et al. 2012; Carnec and Delacourt 2000; Fritschen 2010; Iannacchione et al. 2005; Sen 2013) and does not always correlate well spatially with subsidence, a surface expression of extraction at depth."

Jan 1, 2015

By Jochen Belz, Allan Henneker, Nod Clarke-Hackston

For the construction of tunnels and other underground structures, extraction of the exact amount of material is of paramount importance both economically and for engineering purposes. In the Sequential Support Method (NATM) immediate (sequential)and smooth support by means of shotcrete, steel arches, lattice girders and rockbolts, either singly or in combination are used; cutting of the precise (albeit sometimes of complex geometry) profile is an integral part of the method. In order to save unnecessary excavation and provide better information to the machine operator, VMT GmbH has developed a system to support precise excavation of the tunnel profile when using road headers or other partial face cutting machines. This paper outlines the principles of this system with examples from Australia, Ger-many, Sweden and Spain and will cite examples of typical savings achieved.

Jan 1, 2007

By Ing. Ludwig Schlebusch

The significant growth of the world population and its demand for an increasing standard of living leaves no other choice than continuously augmenting industrial production and making available steadily greater quantities of raw materials at still better qualities. Therefore, any raw material has to be utilized to the greatest possible extent and processed at optimum economy on large mechanical equipment. The layout of processing facilities of large throughput rates can be based on multiple or single lines. The latter enables the application of large machines of optimum size. Proven equipment for homogenizing, classifying, separating superfine material, sorting and dewatering are-now available in optimum sizes. By the use of these large machines operating cost of pit coal preparation plant can be significantly lowered by reducing the specific requirements regarding space, capital investment, energy, operation and maintenance.

Jan 1, 1980

By S. T. Murray

The European industrial minerals industry and its markets are largely self-sufficient. The companies who are members of the Industrial Minerals Association (IMA-Europe) number around 150 contributing 5 billion Euros to the EU?s GDP and range in size from global publicly quoted corporations to small family owned private companies. Their means and capability to implement sustainable development vary considerably. However the leading companies provide an excellent set of best practices, which IMA as a trade association with recognised core competencies in the field of sustainable development is ideally placed to promulgate throughout its membership. As an active participant in the EU Voluntary Scheme for SDI reporting IMA is not only working to increase the level of response to the SDI questionnaire but is also developing with its members a new sustainable development charter which its members will voluntarily adopt as a guiding principle for their implementation of sustainable development This work will be a consultative process involving all IMA?s section members as well as other trade associations, NGOs and MEPs. Public awareness of the benefits of minerals and their contribution to sustainable development has been raised by IMA?s awareness campaign now being followed by a more targeted programme aimed at MEPs. Further work in the future will consider product stewardship and life-cycle analysis. IMA is already positioning itself with the help of its members to assimilate the minerals industry of the accession territories in the sustainable development process.

Jan 1, 2003

By Steve Trussell, William H. Langer

"Arizona aggregate (sand, gravel and crushed stone) producers enjoyed more than a half a century of nearly constant growth in demand for aggregates. Approximately 80 percent of the aggregate produced in Arizona is sand and gravel, and 20 percent is crushed stone (U.S. Geological Survey, 2015). Figure 1 shows the generalized distribution of potential sources of sand and gravel (yellow) and potential sources of crushed stone (other colors described below). Black dots show locations of aggregate operations.Sand and gravel commonly is produced from modern river channels and terraces although some alluvial fans and high-level paleo-river terraces also serve as aggregate resources. The gravel clasts are a mix of rock types that reflect the types of rock in the source area of the rivers. Generally processed river gravels meet stringent specifications for highend uses.Crushed stone, which makes up about 20 percent of production, primarily comes from a variety of metamorphic rocks and light-colored intrusive igneous rocks such as granite (brown areas), dark colored extrusive igneous rocks such as basalt and scoria (rust colored areas), and carbonate rocks such as limestone or dolostone (green areas). Carbonate rocks are also used in the manufacture of cement and lime.Construction and aggregate production in ArizonaBecause aggregate producers have limited facilities for storing product, stockpile changes are insignificant compared to production. Therefore, demand or consumption of aggregate in Arizona is considered to be equal to production. Production figures used in this paper reflect shipments, sales or marketable production, including aggregate used by producers to make readymix concrete and asphalt. Production figures were reported by the U.S. Bureau of Mines from 1950 until 1995 and by the U.S. Geological Survey (USGS) since then. Production figures are reported voluntarily, and major operators are the primary source for these figures. Because many smaller operators do not report their production, the figures are conservative values that provide an approximation of aggregates production activity."

Jan 1, 2015

By Pat DeWilliam

The Yakobi nickel-copper deposit is located essentially at tidewater in the east-central part of Yakobi Island, about 16 1 airline km (100 airline miles) west of Juneau, and can be reached by float plane and boat from Juneau and Sitka. The fishing village of Pelican, population 400, is situated 14.5 km (9 miles) to the east. An unimproved road, approximately 4 km (2.5 miles) long, connects a dock site at Lisianski Strait with the main part of the deposit known as the Basin Area (Fig. I). Other mineral occurrences are known as the Takanis, Flapjack, and Beach Areas. Another smaller nickel-copper deposit is located about 32 km (20 miles) to the south on Western Chichagof Island and is known as the Mirror Harbor nickel-copper deposit. The original discovery of the Yakobi deposit was made by S.H.P. Vevelstad about 1920 and a 47.5-m (156-ft) long adit was driven on the southwest side of the deposit in the Basin Area. The deposit was examined by J.R. Van Fleet of Union Carbide in 1930 and by J.G. Fairchild in September 1931. Stanley and Yates of the International Nickel Co. of Canada (Inco) visited the property in August or September 1937. In 1942, the controlling interest in the deposit, covered by 124 unpatented claims, was said to be held by Vevelstad and associates

Jan 1, 1991

By O. H. Rostad

The importance of geology in ore reserve estimation has been stated by several authors. King et, a1 (1982) reported that the geological factor was the key deficiency where serious weaknesses in ore reserve estimation appeared, especially in grade. The foundation for a successful mining operation is an ore reserve estimate that neither overstates nor understates the true situation as to tonnage and grade. Overestimation of reserves can have devastating economic results. Overestimation of tonnage may lead to wasting money on an overbuilt plant or worse yet, if grade is seriously overestimated also, to undertaking an operation that is doomed to economic failure from the outset. Understated ore reserves can result in building a plant that is smaller than optimum which may result in higher unit costs. At worst, understated tonnage of ore reserves can result in a missed opportunity for a profitable operation. Failure of the ore reserve estimator to properly take into account all geologic and allied factors pertaining to the deposit can result in an ore reserve estimate that is overstated either as to tonnage or grade or both. This paper will focus on these factors and will not discuss rules about distances above or below a drift that should be given a classification of proven or probable, etc. Each deposit has its own particular characteristics which often require modification of general rules for defining limits of proven and probable ore blocks that work satisfactorily in another deposit. A number of references are included which discuss some of these problems. Definitions of ore reserve classifications and an illustration are given in the Appendix.

Jan 1, 1985

By M. K. Mohanty, H. Akbari, L. A. Ackah

Dry separation was the predominant method of coal cleaning in the United States from the 1930s to 1980s. The application peak of dry separators for cleaning raw coal was in 1965, when about 23.1 Mt of cleaned bituminous coal was produced. The main advantage of dry coal cleaning is the elimination RIWKH GHZDWHULQJ VWDJHV DQG VLJQL¿FDQWO\ UHGXFHG moisture in comparison to wet processing. In addition, developed dust control systems have made dry cleaning method an environmentally friendly process. The largest air-based coal cleaning plant was built in Pennsylvania in 1968 and could clean 1,272 t/h of raw coal sized smaller than 19 mm. This was followed by a decline in dry coal cleaning to less than 3.6 Mt in 1988. Some of the main reasons that shifted coal operations IURPGU\WRZHWSURFHVVLQJZHUHWKHQHHGIRUPRUHHI¿FLHQW separations with lower density cuts, increase in raw coal surIDFHPRLVWXUHVSHFL¿FDOO\LQXQGHUJURXQGPLQLQJWRFRQWURO GXVW ¿QHUSDUWLFOHVL]HUHTXLUHPHQWV LQFUHDVHLQ¿QHVLQUDZ coal from underground mines, and health and safety concerns related to dust and noise (Arnold, Hervol and Leonard III, 1991; Miller, 2011).

By Charles H. Minott, Michael J. Markow, Robert D. Wyatt, Fred Moavenzadeh

The substantial investment in tunnels anticipated in the next twenty years has focused new attention on the economics of tunnel construction itself and on some costly problems associated with underground work: the uncertain geologic conditions, the performance and adaptability of men and equipment, and the need for quicker, more efficient excavation methods. There also exists a need to develop better ways of estimating tunnel construction. Inaccuracies in current bid estimates stem from a number of causes, among them (1) the effects of geologic conditions, which are not adequately known prior to construction, (2) the dependence of actual cost on the construction method used and on the interactions among the operations occurring underground, and (3) the reliability of tunneling equipment. Inability to estimate final costs for conventional tunneling more accurately has in turn caused difficulty in gauging the costs and benefits attributable to new tunneling technologies either under development or for which R&D programs are planned. ATTRIBUTES OF THE TUNNEL COST MODEL This paper presents a computer based Tunnel Cost Model (TCM) which quantitatively assesses the uncertainties inherent in underground work, and is detailed enough to aid in preparing estimates or bids. The model employs appropriate techniques of subjective (or "degree of belief") probability and computer simulation of tunnel construction operations to estimate distributions of total tunnel

Jan 1, 1974

By L. Yuan, A. Smith

"NIOSH’s mine fire simulation program, MFIRE, is widely accepted as a standard for assessing and predicting the impact of a fire on the mine ventilation system and the spread of fire contaminants in coal and metal/nonmetal mines, which has been used by U.S. and international companies to simulate fires for planning and response purposes. MFIRE is a dynamic, transient-state, mine ventilation network simulation program that performs normal planning calculations. It can also be used to analyze ventilation networks under thermal and mechanical influence such as changes in ventilation parameters, external influences such as changes in temperature, and internal influences such as a fire. The program output can be used to analyze the effects of these influences on the ventilation system. Since its original development by Michigan Technological University for the Bureau of Mines in the 1970s, several updates have been released over the years. In 2012, NIOSH completed a major redesign and restructuring of the program with the release of MFIRE 3.0. MFIRE’s outdated FORTRAN programming language was replaced with an object-oriented C++ language and packaged into a dynamic link library (DLL). However, the MFIRE 3.0 release made no attempt to change or improve the fire modeling algorithms inherited from its previous version, MFIRE 2.20. This paper reports on improvements that have been made to the fire modeling capabilities of MFIRE 3.0 since its release. These improvements include the addition of fire source models of the t-squared fire and heat release rate curve data file, the addition of a moving fire source for conveyor belt fire simulations, improvement of the fire location algorithm, and the identification and prediction of smoke rollback phenomena. All the improvements discussed in this paper will be termed as MFIRE 3.1 and released by NIOSH in the near future INTRODUCTION The MFIRE program, originally developed in the 1970s by the U.S. Bureau of Mines (now the Office of Mine Safety and Health Research (OMSHR) at the National Institute for Occupational Safety and Health (NIOSH)) and Michigan Technological University, has been a mainstay in modeling of the mutual influences between a fire and the mine ventilation system during an underground mine fire. Several update versions have been released over the years, including MFIRE 1.27, 1.29, 1.30, 2.0/2.01, 2.10, and 2.20. The MFIRE program logically comprises four parts: (1) a conventional network calculation, where it performs the basic network balancing without considering heat or mass transfer; (2) a temperature calculation to establish the reference temperature distribution before a non-steady state (transient-state) simulation; (3) a transient-state simulation that follows changes in ventilation step-by-step to produce a continuous description of the temperature distribution, smoke, and contaminant spread through the ventilation system during a fire event; and (4) a quasi-equilibrium simulation to predict the state of the ventilation system after a relatively long period of time (defaulted as 5 hours in MFIRE) as the fire reaches a quasi-steady state. In summary, MFIRE is a computer simulation program that performs normal ventilation network planning calculations and dynamic transient-state simulation of ventilation networks under a variety of conditions including the influence of natural ventilation, fans, fires, or any combination of these (Chang et al., 1990)."

Jan 1, 2016

By B. G. Kelley

The MIDREX® Direct Reduction Process was developed during the 1960s by the Midland-Ross Corporation, which had pioneered shaft furnace technology and stoichiometric gas reforming for use in processing minerals. In 1969, the first MIDREX® Direct Reduction Plant was built in Portland, OR. Since then, 49 additional modules have been sold in 18 countries. For the last ten years, over 60 percent of the world's direct reduced iron has been produced in MIDREX Plants. During the quarter century since commercialization, many technical improvements have been made, including larger shaft furnaces, in-situ reforming, greater heat recovery, improved catalysts, and hot briquetting. Midrex continues to enhance the technology in the areas of economy-of-scale, energy efficiency, alternate fuels, and raw material flexibility.

Jan 1, 1998

By Laura Suarez, Jörgen Kajberg, Pär Jonsén

How does an investigation into the breakage characterization of electric arc furnace (EAF) manganese slags contribute to a more responsible usage of resources throughout the life cycle of steel products and reduction of carbon emissions? The main goal of this study is to increase the knowledge on the mechanical response of manganese slag to open the potential of pyrometallurgical residues to become secondary material in industrial applications such as infrastructure construction, fillers, binders and soil stabilization, among others.

Mar 1, 2024

By SIMON DIAZ-QUEZADA, HUMBERTO ESTAY

The heap-leaching process is widely used for recovering different metals. In Chile, copper production by heap leaching has been accounting for between 30 and 40 percent of annual copper production over the last 10 years. This level of production has been achieved through and supported by the use of a mathematical relation known as the leaching ratio (LR), which correlates operational parameters with metal extraction in a heap-leaching operation. In spite of the widespread industrial use of this relation, few scientific studies mention it. This disparity between industrial practice and scientific research could lead to operational decisions that lack substantial theoretical support and to scientific studies with limited industrial impact. This study describes the LR and its current uses and limitations.

By G. F. Joklik

Although the mineral shortages of twelve to eighteen months ago have given way to oversupply, their memory lingers on. These problems were man-made: booming demand throughout the industrial world, political and industrial unrest and the oil embargo all contributed. But in the minds of many, the shortages conjured up visions of the depletion of the world's mineral resources, a disaster that could be staved off only by drastic curbs on consumption and therefore, curbs on economic growth. A little historical research shows that fears such as this are not inventions of the 1970's. A hundred years ago, for example, the imminent exhaustion of the world's coal supplies was being predicted in Great Britain. The English economist, John Stuart Mill, who was usually more perceptive, wrote a few years earlier that "it is only in the backward countries of the world that increased production is still an important object". And later there was Franklin Roosevelt who said in 1932, "Our industrial plant is built; the problem just now is whether under existing conditions, it is not overbuilt". His concern, in other words, was not with the discovery and exploitation of new natural resources, but with the administration of known resources and with seeking foreign markets for surplus production. In light of copper prices at the time -- just under 6¢ a pound -- that was understandable. These instances illustrate how, throughout the world's industrial history, concern about surpluses of raw materials has alternated with alarm about the adequacy of supplies and with calls for restricting growth.

Jan 1, 1975