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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 Alexander N. Winchell

The construction and erection of the Coleraine concentrating plant was commenced in April, 1909, and was completed (with the machinery installed) ready for use in 1910. Attached to the main building is 'a table house large enough to accommodate con¬centrating tables for five units and space for a small machine shop and supply store. For the handling of the' railroad cars in the upper portion of the mill there is provided on the north side of the main structure a trestle approach 650 feet long, and on the south or opposite side a tail track 300 feet long. The latter is so constructed as to permit its being incorporated directly in a possible future extension of the plant. The building, viaduct approach and tail, trestle, as well as the table house, are con¬structed of steel, the total amount used being 6,100 tons. The building is covered by corrugated' steel sheeting over 2 x 6-inch wood sheathing fastened directly to the structural steel. The north end of the trestle approach is connected with the main road-beds forming the track system for delivery of the crude ore to the plant over an embankment of a maximum height of 110 feet containing over 2,000,000 cubic yards of dirt.

Jan 1, 1920

By Dion Weatherley, Raúl Castro, RENE GOMEZ, Pablo Cid

The study examines the impact of different drawbell geometries on hang-ups during ore extraction in underground mining. Using the discrete element method, the research compares three drawbell geometries: drawer, circular, and El Teniente. The findings indicate that the El Teniente geometry experienced more hang-up events, while the circular geometry had fewer.

Sep 1, 2023

By Claudia Castillo, Katja Freitag, Jan Cilliers, Diana Drinkwater, Robert Seitz

The talent gap in mining is not a new challenge. Mining companies continue to seek innovative ways to attract, develop and retain talent, and younger workers are looking for opportunities to develop their professional careers. Training provides a key value proposition for both employees and employers as it helps build a talent pipeline while offering opportunities for learning and growth and value creation. In 2020, Metcelerate launched its 20-month program for early career mineral processing engineers. The program helps develop critical technical skills in the workplace and is a tool to identify motivated engineers and change culture within teams. Learners cap their skills development by executing a technical investigation. This generates immediate value—a win-win outcome for learner and company.

Feb 1, 2025

By Robert E. Murray

The title of my paper, "A Company's Response to Federal Coal Leasing," brings to mind a picture of a dog chasing its tail. This is what the coal industry, has been doing since the Federal coal leasing moratorium went into effect in 1971. We've gone around in many circles, but we are only very slowly, if at all, getting closer to catching our tails, i.e., efficient, economical, and rational Federal coal leasing. My companies, The North American Coal Corporation and its four Subsidiaries, The Falkirk and Western Plains Mining Companies and The Coteau and Missouri Valley Properties Companies, together hold in excess of 4.5 billion tons of lignite reserves in North Dakota. Some of our North Dakota properties are substantially interspersed with Federal coal, with the government holding title to the minerals in every other section. This checkerboard pattern of Federal ownership has made it difficult to develop and market some of our reserves, and, as a result, it has become imperative that we be familiar with and active in the Federal Coal Leasing Program.

Jan 1, 1982

By Yang Song, Li Shaokang, Wang Zhiqiang, Wang Jinjun, Li Guofeng, Su Meixuan

The paper investigates the triboelectric charging properties of calcium carbonate (CaCO3) particles under different conditions using a cyclone tribocharger. It explores the effects of airflow velocity, tribocharge material, and particle moving distance on the charge-to-mass ratio of CaCO3 particles. The study aims to provide guidance for the design of triboelectric separation systems for magnesite.

Sep 1, 2023

By Kousik Sinha

The advantage of using a clean coal as a feedstock in a direct liquefaction plant is improved performance of the plant by several factors e.g., increased throughput of coal; reduced wear and tear of valves, pipes, and pumps; increased liquid yields, etc. This paper examines the technical feasibility for cleaning Illinois #6 coal as a feedstock to a direct coal liquefaction plant via selective agglomeration using a coal-derived heavy distillate, Wilsonville V-1074 as agglomerant. Effects of addition of Kerosene or coal-derived Naphtha as conditioner, coal particle size, slurry pH, oil to coal ratio, and operating temperature on ash reduction and clean coal weight recovery have been studied. Results show that about 70% of the ash can be removed from this coal and the clean coal weight recovery over 85% can be achieved by using this technique with suitable selection of coal particle size, slurry pH, mixing intensity and oil to coal ratio.

Jan 1, 1991

By D. M. Abbott

The problem with best practices occurs when they do not work. This happens when the seldom-stated assumptions underlying the practice are not met. This paper provides some examples for the mining industry: (1) when core splitting is inappropriate, (2) when the use of fire assays for placer samples is inappropriate, and (3) when high-grading may be acceptable. Geologic conclusions are, in the final analysis, expressions of judgment predicated upon knowledge and experience. A geologic conclusion, however, purports to be more than an arbitrary determination—it is reached as a consequence of method. No specific method is required, but the method used must be an orthodox method, in accordance with orthodox definition of terms, and the one best adapted to the dealing with the questions asked about the property in question. Whether the so-called “best practice” is really applicable to the job at hand must be decided on the basis of professional scientific judgment. When one decides to deviate from a published “best practice” for sound scientific reasons, describe in detail in the report what the so-called “best practice” is, why it was inappropriate for the project, and why the method used was better. If one becomes aware that a “best practice” is being proposed, actively urge those proposing it to include in its description the underlying assumptions that must be met in order for the “best practice” to be valid.

Jan 1, 2014

By David Hartley

United States Steel Corporation Minntac Mine is located at Mt. Iron, Minnesota, on the Mesabi Iron Range. The taconite pit is two miles long by a mile wide, with a maximum depth of 170 feet. This paper will deal with the radio remote control of locomotives engaged in the railroad haulage of crude ore and waste rock at this property.

Jan 1, 1970

By David B. Costain

Three dimensional surface approximations are important means of evaluating physical and environmental factors that affect surface coal mining and reclamation. Computer approximated surfaces are projected as an array of square grid cells where individual cells define each parameter value respective to locations on the grid. Grid surfaces or grid cells within a surface can be compared or modified through application of standard mathematical functions. Surface approximations can be used to define the quantity and quality of marketable coal and to evaluate thickness and quality of overburden. Surface approximations also can be used to evaluate overburden swell factors wherein changes in post-mine topographic relief are related to expansion of unconsolidated materials in the backfill. Application of computer approximated surface to analysis of approximate original contour (AOC) standards allows an assessment of the quantity and geographical displacement of overburden and the distribution and numerical level of slope.

Jan 1, 1984

By Bradley S. Van Gosen, Anjana K. Shah, George M. Bedinger, Donald I. Bleiwas, Karl J. Ellefsen

"Ancient and modern coastal deposits of heavy mineral sands (HMS) are the principal source of several heavy industrial minerals, with mining and processing operations on every continent except Antarctica. For example, HMS deposits are the main source of titanium feedstock for the titanium dioxide (TiO2) pigments industry, obtained from the minerals ilmenite (Fe2+TiO3), rutile (TiO2) and leucoxene (an alteration product of ilmenite). HMS deposits are also the principal source of zircon (ZrSiO4), from which zirconium dioxide (ZrO2) is obtained for uses mostly in refractory products. Sometimes monazite [(Ce,La,Nd,Th) PO4] is recovered as a byproduct mineral, sought for its rare earth elements, and thorium (Ault and others, 2016; Sengupta and Van Gosen, 2016; Van Gosen and Tulsidas, 2016).HMS are sediments containing dense (heavy) minerals that accumulate with sand, silt and clay in coastal environments, locally forming economic concentrations of the heavy minerals (Fig. 1). Economic (mined) HMS deposits include Holocene sediments on modern coasts, such as examples in India and Brazil, as well as coastal deposits formed by transgressions and regressions of the seas during intervals in the Quaternary, Tertiary and Cretaceous, such as in Australia and the southeastern United States. Economic deposits typically contain heavy-mineral concentrations of at least two percent. Individual heavy minerals are commonly defined as minerals with a specific gravity greater than approximately 2.9 g/cm3. These minerals are generally resistant to chemical weathering and physical degradation and thus survive well in fluvial and coastal environments. Heavy minerals in coastal HMS deposits may include, in order of general abundance, ilmenite, leucoxene, rutile, magnetite, zircon, staurolite, kyanite, sillimanite, tourmaline, garnet, epidote, hornblende, spinel, iron oxides, sulfides, anatase, monazite, cassiterite and xenotime. Of these, ilmenite, leucoxene, rutile and zircon are the primary economic minerals. Garnet, monazite, cassiterite and xenotime are occasionally recovered as byproducts. The heavy minerals as a suite typically make up no more than 15 weight percent of a deposit and usually much less. Quartz and clay minerals form the bulk of the sediment. The geology of HMS deposits and examples of significant districts are summarized in Van Gosen and others (2014) and Hou and Keeling (2016)."

Oct 1, 2016

By M. K. Boateng, K. Awuah-Offei

"Language barrier in a workplace affects workers’ productivity and safety. The objectives of this paper are to: (1) review the various approaches for breaking language barriers among miners; and (2) analyze the costs and benefits of these approaches, and make recommendations on the way forward. The authors achieve these objectives by reviewing the current approaches in breaking language barriers among miners. The review reveals that some of these approaches can be expensive with less benefits. Thus, it is concluded that mining companies should carefully select the optimal approach to break language barrier. INTRODUCTION Multi-national mining companies have expanded their operations into non-traditional mining destinations to grow and meet market expectations. For instance, Newmont Mining Corporation has about 14 operations and projects located in Africa, Asia, Australia and America (Newmont Mining Corporation Operations and Projects, 2015). Similarly, Freeport-McMoRan operates about 14 mines in North America, South America, Southern Asia, and Africa (Freeport-McMoRan Inc., 2015). Some mining companies have also attracted expatriate workers into their workforce. For example, Ma’aden, the Saudi Arabian mining company, in its 2013 annual report states that 34% of its total employees are expatriates (Ma'aden, 2013). Expatriates constitute a key source of skilled labor and facilitate skill transfer. The success of many international operations relies greatly on expatriate performance (Erbacher, D'Netto & Espana, 2006). Even companies that do not expand their operations into other foreign countries still have to deal with language barriers due to changing language demography of the country and the areas from which labor is sourced. For example, the language composition of the workforce and languages used in South African mines is diverse with miners proficient in Afrikaans, English, Zulu, Xhosa and others to varying degrees (Research Focus (Pty) Ltd, 2011). As a result of these trends, most mines today operate with a multinational workforce. This means cultural differences, including language barriers, exist among the miners. Marschan-Piekkari, Welch and Welch (1999) emphasize the fact that language problems become prominent as companies internationalize and grow their operations into more countries. According to a survey by Forbes, language barrier affects operations. For example, business owners acknowledge that language proficiency may promote a safer work environment (Rubin, 2011). A research has shown that language and cultural barriers in a workplace contributes to reducing workers’ productivity, increasing accidents, and hurts employers’ ability to recruit, hire and retain workers (Morris, 2002). Hence, mines are making efforts to break language barriers in their operating environments. Ma’aden, for instance reported in 2013 that 1,506 of its employees received training in English as a second language (Ma'aden, 2013)."

Jan 1, 2016

By James R. Aggson

This paper summarizes the research effort that was conducted as part of a cooperative agreement between the U.S. Bureau of Mines, Denver Mining Research Center and the Pittston Company. The objective of this investigation was to further the understanding of the floor heave ground control problems that have plagued underground mining of the Beckley coalbed in southern West Virginia. Floor heave is both economically and structurally undesirable. Floor heave is accompanied by a redistribution of stresses and loads that are associated with an underground opening. This redistribution of stresses may cause roof or pillar problems that otherwise would not have occurred. The floor heave that occurs in the Beckley coalbed is not cons1dered to be caused by "squeezing" or plastic flow of the materials involved. The "squeezing" type floor heave is normally associated with relatively weak floor members that contain significant amounts of clay mineralization. The floor members in the Beckley coalbed are competent, relatively strong materials which fail in a manner that can best be described by the term "buckling." This buckling-type failure is indirectly related to the time-dependent deformation properties of the materials involved, but is considered to be more of a slender column, or panel, type failure than a "squeeze" or "flow"-related failure. The Beckley coalbed has had a history of floor heave ground control problems. The Glen Rogers mine, which opened in the 1920's, experienced extensive floor heave. In a report dated April 1929, James P. Keatley of the West Virginia State Department of Mines described the floor heave in the Glen Rogers mine. Several observations listed in the Glen Rogers report that appear to be consistent with current observations follow: 1. Water plays no apparent part in the floor heave process. 2. No evidence of gas has been found in the floor. 3. The thickness of the overburden, which varies from 183 to 396 m (600 to 1300 ft), has no relationship to the floor heave. In the conclusions of the 1929 report on the Glen Rogers mine, Keatley states, "A statement in brief as to the cause (of floor heave) would lie that an undetermined natural condition doubtless augmented by former and present mining methods causes the bottom to heave." As this report will show, Mr. Keatley's insight into the problem was most accurate. The "undetermined natural condition" is the existence of a biaxial, horizontal, compressive stress field. This stress field is in excess of that which would be expected from gravity loading. This stress field and the material properties of the floor rock combine to cause the floor heave that has been experienced. The floor heave that occurs in the Beckley seam generally occurs as arching, with a tension fracture, near the center of the floor span or as a break near the rib followed by vertical deflection (of the floor) at the rib and sloping of the floor across the entry. Examples of the floor heave are shown in Figures 1 and 2. The two types of floor heave are merely different manifestations of the same basic failure mechanism. When the entries experiencing floor heave were identified on a map of the mine under investigation, it was apparent that there was a relationship between the floor heave and the direction of the entries. The main entries, which are used for ventilation and haulage, experienced the majority of the floor heave. This directional relationship suggested a directionally related loading mechanism, or more specifically, a biaxial, horizontal stress field that exceeds what would be expected by gravity loading. Since the main entries were oriented at a bearing of N25oW, it was hypothesized that the maximum compressive component of the horizontal stress field was at 90° to these entries or at a bearing of N65oE. An in Situ testing program was developed to test this hypothesis and investigate the floor heave problem.

Jan 1, 1978

By M. C. Fuerstenau

The zero-points-of-charge of apatite, calcite, and fluorite are pH 6.4, 10.8, and 10.0, respectively. Scheelite is negatively charged above at least pH 3. Flotation responses of these minerals in the presence of potassium oleate and sodium silicate are presented and compared with electrokinetic data. Colloidal silica appears to be the species principally responsible for calcite depression, while silicate anion is the species responsible for fluorite depression. Additions as high as 1 x 10-3 mole/liter silicate have no effect on the flotation responses of apatite and scheelite. Selective flotation of nonmetallic minerals is difficult to achieve with fatty acids or soaps by themselves. As a result, specific reagents are added to aid these separations, and one of the reagents commonly employed for this purpose is sodium silicate. Flotation separations of various calcium¬ bearing minerals such as fluorite from calcite (1,2,3) and scheelite from calcite(24) and apatite(2,5) almost always involve the use of sodium silicate, for example. The mechanisms by which sodium silicate functions as a depressant are still not understood; this fact is probably due to a number of reasons. That is, the dissolution process of sodium silicate is complex, giving rise to a number of ionic and colloidal species. (6) In addition, the type and concentration of these species depend on the ratio of Na20 to Si02, the concentration of sodium silicate, and the pH of the system. (6) At the present time, it is not known which species, colloidal silica or silicate anion, is responsible for depression. If colloidal silica is the species that is adsorbing, then adsorption must occur by electrostatic attraction between the colloid and the mineral surface. Silicate anion, on the other hand, may adsorb either physically or chemically. The objective of this paper is to determine first the active species of sodium silicate and then the conditions under which this species will adsorb and function as a depressant.

Jan 1, 1968

By Felicia F. Peng

The naturally occurring aged manganese oxide coated on the granular media was found to have a catalytic effect on the removal of low concentration of Mn(II) (-1 ppm) from drinking water. Applying this principle, a manganese removal technique was developed for removal of higher concentration of Mn(II) (-100 ppm) from mine drainage by using various aged filter media and synthesized granular media with manganese oxide coatings. Laboratory-scale continuous granular media column experiments were conducted to assess the feasibility of manganese oxide-coated granular media for Mn(II) removal from synthesized mine drainage. The removals of Mn(II) were evaluated as a function of operation parameters including solution pH, manganese oxide concentration coated on the media, interstitial velocity, and oxidant concentration of influent. Higher solution pH and/or higher manganese oxide concentration promoted the removal of Mn(II) on the oxide-coated granular media under low interstitial velocity. Addition of sodium hypochlorite as an oxidant in the influent resulted in continuously regenerated oxidized surface to serve as the catalyst for Mn(II) oxidation reaction on the surface of oxide-coated media.

Jan 1, 1994

By George Fumich

The Office of Coal Research has been supporting the development of processes for producing synthetic pipeline gas from coal since 1964. .Some of this work has also been jointly supported by the American Gas Association. The work has progressed through laboratory investigation, to bench scale, to pilot plant. It was far from a crash program, generally being fund-limited.. As of one year ago, we had reached the following position: 1. The Institute of Gas Technology HYGAS. process pilot plant in Chicago, Illinois, was in the process of being finally completed. This plant is designed to produce about 1,500,000 cubic feet of pipeline-quality gas per day from 75 tons of coal. 2. The Consolidation Coal Company, CO2 Acceptor Process pilot plant in Rapid City, South Dakota, was well._ on its way to completion. This plant, designed primarily for lignite and subbituminous coals, has about one-half the design capacity of the HYGAS plant. Additionally, the initial construction did not provide for cleanup and methanation; only the preliminary synthesis gas is produced. 3. The Bituminous Coal Research, Inca, BI-GAS pilot plant was in a preliminary design stage. A site had been selected near Homer City, Pennsylvania, to build this plant, planned to consume 120 tons of coal per day. Meanwhile, as you are all well aware, a natural gas shortage was developing in this country. Much has been published about it, so I will not. bother you with further details. Suffice it to say that the reserve-to-production ratio has been steadily declining, because we have been using.-as-faster than we have been find-

Jan 1, 1972

By Zoë Dugdale, Gerald Poplin, Tim Bauerle

"Fatigue presents several challenges for the mining industry. Depending on the specific occupation, daily work or operational setup on any given mine site, mining jobs can have a fair amount of labor-intensive tasks mixed with monotonous and repetitive duties. Combined with the long working hours and shift-work schedules of mining work, the prevalence of fatigue in mine workers may seem rather unsurprising.Mining is certainly not alone in facing the challenge of addressing worker fatigue. Indeed, many of the characteristics above mirror the similarities of fatigue in other industries, such as health care, aviation and security. To the extent that fatigue in mining acts like fatigue in any other industry, then any fatigue management applications, trainings, or interventions in existence can be borrowed from other industries and applied to mining in a cookie-cutter approach. However, some have argued that mining in particular is especially susceptible to increases in the prevalence of fatigue beyond the characteristics listed above due to the multifaceted combination of factors in mining environments associated with fatigue: dim lighting; limited visual acuity; hot temperatures; loud noise; highly repetitive, sustained, and monotonous tasks; shiftwork; long work hours; long commute times due to mine site remoteness; early morning awakenings; and generally poor sleep habits (Canadian Centre for Occupational Health and Safety, 2012; Legault, 2011). Legault (2011) in particular argues that it is the combination of these factors simultaneously that can make mineworkers particularly susceptible to sleep deprivation and fatigue in comparison to other industries where these factors are often not present all together. If fatigue looks and acts different in mining, as others have argued, more research is needed to determine if, how, and why worker fatigue might need to be managed differently in mining.While the burden of fatigue on the mining population has not yet been evaluated thoroughly, methods and measures of fatigue management remain a popular point of discussion. Many commercial suppliers and consultancy groups have begun to develop technologically based fatigue monitoring systems (McMillian, 2013). Some technologies can monitor vehicle operators for indicators of wakefulness, such as percent eyelid"

Jan 3, 2018

By CHENCHEN SUN, GUOPING LUO, GUOCHENG ZHANG

In this study, the conditions of raw materials and fuels were simulated for Bayan Obo iron ore concentrate by adding pure calcium fluoride (CaF2) in various concentrations to Australian iron ore. The mechanism by which the fluorine (F) content of the lattice influenced the reduction swelling properties of the iron ore briquettes during various stages of the reduction process was investigated. The results provide insight into the mechanism governing the reduction swelling process in Bayan Obo ore briquettes, which could be used to direct real?world production practices, particularly those related to the rational utilization of Bayan Obo ore resources.

By J. Herhold, S. Plaum

The focus within the economical optimization of projects, which are conducted underground, shifts more and more towards the conduction of construction work underground. Underground operations can be defined in a wide range of various projects, from underground mining tasks to the construction of engineering structures. Within these projects the conduction of construction work cannot only be defined as absolutely necessary, but sometimes also as optimizing for underground processes (e. g. installation of workshops underground to support the mining processes). Even though the conduction of underground construction might cause positive outcomes concerning the productivity, it also tends to be challenging due to local (sub-surface) conditions and influences. To minimize the risk of failure and sudden events within in the conduction of construction work underground, the tool “work preparation” shall be used. Under the given constraints, such as local influences, expected construction work and set time frame, the conduction of the construction work will be planned in advance by consideration of the construction logistics as well as the selection of a fitted construction technique. PROBLEM DEFINITION Economic Challenges - Raw Material Extraction Enterprises in the construction, mining and raw material extraction industries are increasingly under the pressure to perform economically to sustain their position on the global market. Profitability, efficiency and productivity are the basic conditions to be an active participant on the global market as well as a business partner and contractor for mining and construction projects or projects related to the extraction of raw materials. The completion of large-scale as well as common construction projects above ground has been under the pressure to minimize costs and time whilst maximizing the potential outcome, in the meanings of quality and economic gain, for more than a decade now. Whereas the construction industry has to fight the competition on the market with efficient project outcomes, the mining industry has to find ways to perform efficiently to further conduct the extraction of decreasing raw material deposits. The ongoing exploitation of existing raw material deposits to satisfy the constantly increasing raw material demands world-wide, led to the predicament that economically mineable deposits have decreased dramatically. Even tough mineral deposits do still exist on a global level, near-surface deposits decrease rapidly. Therefore, the extraction of raw materials within mining operations will be relocated further away from the surface in greater depths. With the growing distance from the surface to the mineral deposit, the extraction costs will increase many times over. With that in mind, the extraction costs will increase whilst the economic efficiency will decrease. The extraction of certain deposits will no longer be profitable with the common approach. To further extract raw materials efficiently even in greater depth, companies have to change their practice in different ways. That leads to the fact, if the deposits are in the depths, where the extraction processes won´t be economically, other (support) processes have to be in order to guaranty an economical corporate process itself. This precept will divert the focus from the actual mining process to support processes, where potential for optimization still can be found, as shown in figure 1.

Jan 1, 2019

By Terry W. Engelhart

"A computer-based approach to online supervisory control and operations management of bulk materials handling terminals". This paper describes an integrated computer facility supporting the functions and responsibilities of shift operations, scheduling, maintenance and management using real-time interactive techniques. The functions and responsibilities as related to coal export terminals are specifically addressed, although these functions would be equally applicable to other terminal configurations and other commodities. A discussion of the resulting benefits are presented: - throughput efficiency - long-term planning and scheduling, using simulation - operations monitoring and protection - demurrage/despatch optimization - preventative maintenance - operational productivity

Jan 1, 1982