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By A. Haghighat, B. Lattimer

"Mine face ignition due to a high levels of methane is one of the most common fire incidents in underground coal mines. This work exams ignition scenarios in continuous miner headings. Depending on the magnitude of the ignition or resulting fire, the ventilation curtain in the continuous miner (CM) heading may be damaged or dislodged, affecting the ventilation into the area. A computational study was conducted to investigate the effects of different levels of damage to the ventilation curtain on the ventilation flow into the CM area. The computational fluid dynamics software Fire Dynamics Simulator (FDS), Version 6.0 was used to predict the conditions that develop due to a 200 kW fire in the coal mine face following a methane ignition with different levels of curtain damage. Smoke layer depth, temperatures and mass flow into the CM area were used to evaluate the impact of no damage to the curtain, partially dislodged curtain, and fully removed of the curtain. Partial removal of the curtain allowed more smoke to accumulate in the CM area and a reduction in ventilation into the CM area. With full removal of the curtain, the smoke accumulated through the entire depth of the CM area and flowed out the entrance to the CM area and the ventilation completely bypassed the region. INTRODUCTION Active working faces in underground coal mines are one the most hazardous locations in terms of fire events. According to Mine Safety and Health Administration (MSHA) data analysis, the highest number of non-fatal fire incidents was reported at mining faces, intersections and crosscut areas in comparison with other locations from 2000 to 2012. About 464 fires happened at active working faces from 2000 to 2012, most consisting of a methane ignition, in some cases followed by localized fire. These are high risk incidents due to the potential to raise float dust and damage ventilation systems, particularly auxiliary systems such as curtain or tubing. Depending on the magnitude of the ignition or fire, the ventilation curtain in the continuous miner (CM) area may be damaged or dislodged, affecting the ventilation into the area. Five computational fluid dynamics (CFD) scenarios were considered to investigate the smoke layer depth, temperature, visibility, mass flow rate, and the behavior of airflow in an entry with a continuous miner (CM) located in it. The state of the auxiliary ventilation was varied based on the assumption that as an ignition increases it magnitude it will affect ventilation curtain proportionally. Visibility and temperature along the height of the entry at different sections were investigated and the interface height at each section was determined. Also, the fresh air height was studied for tenability analysis in future. FDS, Version 6.0 was used to predict the conditions that develop due to a 200 kW fire on the coal mine face following a methane ignition with different levels of curtain damage. Smoke view software was used as the post processor to visualize and analyze methane fire behavior at the face. Most entry fires are reported as fuel-controlled fires as they are rarely restricted to air access (Ingason et al, 2014). The working face fire in the following models was assumed to be a fuel-controlled fire."

Jan 1, 2016

By H. B. Weaver

The development of a method to manufacture diamonds has been rated as one of the out- standing scientific achievements of our time. The story is both interesting and significant. This paper will quickly review history of diamond and manufactured diamond. Next, it will discuss manufactured diamond as a product -- how good is it -- and what is the significance of this scientific achievement. And finally, present a few thoughts about the future of this technology and this product. For centuries, diamond was found only in alluvial deposits, primarily in the Golconda fields of India. As a result, man knew nothing of the process by which the stones were formed. In 1860, diamonds were found in South Africa under completely different conditions. Here, for the first time, they were found in volcanic pipe -- their mother ground. These volcanic pipes are roughly cylindrical columns of rock which go deep within the earth. The theory as to the formation of diamond was presented by the geologists in that era. The theory states that molten rock was thrust up through a layer of carbonaceous shale where it picked up the carbon necessary for diamond formation. It was generally agreed that diamond was formed approximately 240 miles below the surface of the earth, thus indicating that extremely high temperatures and pressures were involved.

Jan 1, 1964

By R. L. Grayson

Evidence has accumulated indicating that cultural change toward safer workplace behaviors is beginning to occur systematically in the coal industry. Through a range of programmatic mining company successes, enforcement and litigative actions, economic responses to competition, and integrated efforts by federal and state agencies, a broader participation of safety and training professionals is being achieved to address prioritized workplace problems at mines. Small steps in workplace-related improvements have been realized already, but the trends in industry safety statistics, coupled with focused programmatic initiatives, indicate that more definitive and systematic steps are occurring to improve safe behavior in the workplace routinely.

Jan 1, 1996

By Duluth Engineers' Club, Engineers' Club of Northern Minnesota

"In recent years, much has been said and written on Lake Superior ores, giving the impression that the quality of the ore is deteriorating in grade and that the reserve of high grade ore is rapidly being depleted. Average analyses of ore produced in this district since 1902 show that the average quality has been practically uniform since 1910, and now closely approximates the average for the total reserves of merchantable ore.The accompanying tables and charts show the average analyses for the past ten years, weighted according to tonnage: The chart above shows graphically the average natural iron content for the old range, Mesabi, and grand total Lake Superior ore shipments since 1902.During the last ten years the decrease in iron content for shipments from all ranges except the Menominee was only' .05 of 1 per cent, while for the Menominee ores there was an increase of .052 of 1 per cent. These tabulations and the chart prove that the average quality of the total annual production of iron ore from the Lake Superior district is uniform. Mining men of the district know that all of the merchantable ores of every ore body are being mined out cleanly, and therefore the present average iron ore content of total annual shipments from the district may be expected to continue as long as the present merchantable ore reserves last. There is no logical reason to expect a decrease in the average iron content. Furnaces require ore of definite quality, and if this quality of ore cannot be produced from the natural ore bodies, it must be produced by mechanical means—that is, by concentration of low grade ores or iron formation."

Jan 1, 1920

By D. A. Meyer

The long and arduous process of bringing aggregate produced in Mexico to the Gulf Coast of the United States really began in the 1970s when the first exploratory trips were taken by Vulcan's geologists. It was not until the middle of the 1980s that all of the elements of the project seemed favorable and the largest capital investment in Vulcan's history was given the green light. The history of the project will be covered along with a discussion of the role that market forecasting played in the process. Is this the first of many or a once in a lifetime project? In July 1987, Vulcan and its joint venture partner broke ground in Mexico for a world-class limestone quarry and crushed stone production facility. This project is the largest ever undertaken by Vulcan's Construction Materials Group, with a total cost of over 200 million dollars -a cost shared equally by Vulcan and its joint venture partner, Ingenieros Civiles Associados, or ICA, a diversified Mexican company which is also the largest construction firm in Latin America.

Jan 1, 1995

By D. H. Dvorak

Two pilot-scale biological reactor systems were installed to treat metal-contaminated water. The reactors consisted of barrels and tanks filled with spent mushroom compost, within which bacterial sulfate reduction became established. Concentrations of Fe, Zn, Mn, Ni, and Cd were lowered by over 95% as these metals were precipitated as insoluble sulfides by reaction with bacterially generated H2S. The chemistry of the reactor systems is examined, and opportunities for maximizing their metal-retaining and alkalinity-generating potentials are discussed.

Jan 1, 1991

By G. S. S. Raman, M. S. Klima

Coal refuse slurries stored in tailings impoundments can potentially lead to environmental concerns such as effluent seepage, property devaluation, and in extreme cases, dam failures. Pressure filtration offers an opportunity to reduce the impoundment requirements by providing significantly drier solids. A full-factorial design was used to study the effects of temperature and pH on dewatering a refuse slurry obtained from a coal preparation facility in Pennsylvania, USA. The experimental results indicated a strong effect of temperature on cake moisture as the cake moisture after about 2800 s was 22% at 43 °C and only 36% at 10 °C for tests conducted at pH 3. ANOVA results confirmed the statistical significance of pH, temperature, and their interaction effect. Also, the results showed no significant differences between the tests conducted near neutral and alkaline pH values at low and ambient temperatures. On the other hand, Tukey’s test indicated higher reductions in cake moisture at higher temperatures for lower pH values. This study affirms the need to monitor and control the pressure filtration process as throughput could significantly vary with changes in temperature and slurry conditions.

By J. Engesser

A research project supported by the Minnesota Department of Natural Resources and the Iron Ore Cooperative Research Committee was undertaken to reduce the dissolution of fluoride into process water during taconite processing. Leach tests were conducted using rod mill feed samples and water containing varying concentrations of calcium and sodium. Laboratory liberation grinds were performed to evaluate fluoride rejection during grinding and magnetic separation. Tube furnace tests were conducted to evaluate fluoride volatilization during pellet induration. The results indicate that fluoride concentration of process water is a function of both calcium and sodium concentration in process water. It appears that less than 1 percent of the fluoride present in rod mill feed will dissolve in process water during grinding. More than 90 percent of the fluoride present in rod mill feed is rejected with tailings during size reduction and magnetic separation. The furnace tests demonstrate that bentonite and fluxstone (calcite and dolomite) addition to taconite concentrate during pellet production increases the amount of fluoride that volatilizes during induration. Lime hydrate addition to pellets decreases the amount of fluoride that volatilizes during pellet induration. During acid pellet production approximately three times more fluoride enters the water during induration-off-gas scrubbing than during grinding. When fluxed pellets are produced three to eight times more fluoride enters the water during off-gas scrubbing than during taconite grinding.

Jan 1, 2004

By William Laird

In the process of mining coal today, our greatest asset, the coal miner, is faced with the indirect and direct consequence of underground mining operations. The indirect considerations may be the rank of the coal seam, the amount of overburden, geological factors, seam permeability and cracks. The introduction of newer, bigger and faster coal-producing face equipment having the capability to cut or rip through the bedding planes, cleats and micropores of the coal seam brings about rapid liberation of gas accompanied by greater concentrations of coal dust, has exerted a direct consideration and greater demand upon mine ventilation systems and dust control. The purpose of mine ventilation is to provide sufficient pure air to the miners working underground and to dilute, render harmless, and carry away all the dangerous and noxious gases. The mining operations which create coal dust are cod cutting, drilling, blasting, loading, hauling, dumping and movement of face equipment. The created fine dust causes the propagation of explosions. When quantities of coal dust with no methane present are raked in a sufficiently dense cloud in the presence of a source of ignition, an explosion is possible.

Jan 1, 1980

By C. J. Webb

Abandoned uranium mines in the southern Black Hills of South Dakota were sampled for uranium, radium, and rare earth elements during 1992 and 1993. Analyses of water samples from several shallow ponds in the mine pits showed pH values between 3 and 4 with uranium concentrations between 1600 and 2600 ppb. Rare earth elements and their respective isotopes were analyzed with an inductively coupled plasma mass spectrometer and were referenced to a shale normalization pattern. All samples showed an enrichment in the middle rare earth elements. Rare earth levels often were greater than 0.2 ppm. At one site, the concentrations of lanthanides were 150,000 times above background levels. While the southern Black Hills have long been known for rich uranium ore deposits, these analyses show that significant levels of rare earth elements also are present, indicating that the potential exist for future development.

Jan 1, 1995

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 T. A. Gray

There are several potential large-volume uses for coal ash in mining-related applications that could be environmentally and economically beneficial to mining companies. Actual usage, however, may be constrained by regulations or by perceptions of coal ash and the potential uses. To identify currently allowed uses and to assess constraints to coal ash use in the eastern coal fields, questionnaires were sent to state coal mining agencies to determine their policies on coal ash utilization and to mining companies to solicit their viewpoints on coal ash utilization. Identifying and understanding the constraints will allow for the development of a coordinated and consistent approach to remove or reduce these constraints and possibly allow for increased utilization of coal ash by the mining industry. This paper summarizes the findings of our investigation.

Jan 1, 1995

By John H. Smith

Because of increased pressure from Federal & State Regulatory Agencies, most acid flows will require some sort of treatment prior to being discharged to receiving streams. In many industries, the volumes of liquors are large and their acid content varied. Pressure to minimize costs of waste treatment equipment and land usage makes development of a treatment process incorporating these desires mandatory. "Standard" methods of acid neutralization with lime have been known for years, however, the volume and characteristics of the resultant precipitated solids can create a disposal problem. Also, when standard lime treatment is used, the settling characteristic of the precipitated solids is normally slow. In some instances, the necessity of added dissolved solids removal, (such as iron, needing aeration) add to the problem of concentrating neutralized solids. In a paper published in the September 1970 issue of "Coal Age," *the results of extensive test work by personnel of the Homer Research Laboratories of Bethlehem Steel Corporation, Bethlehem Pa., were reported. This paper dealt specifically with development of a flow sheet to treat acid mine drainage (hereafter referred to as AMD) from coal mine operations. Regulations on discharged water required basic pH and low dissolved iron content after treatment. Liquid flows of over 9 MGD from

Jan 1, 1972

By G. J. Hodges

The Stillwater Mining Company, a partnership of Pittsburg & Midway Coal Mining Co. and Manville Corporation, operates a precious metals smelter at Columbus, Montana to further up-grade concentrates from its platinum/palladium mine. The smelter began operation in the summer of 1990. The gas cleaning system in the facility utilizes "oxidation/dilute mode" dual-alkali scrubbing technology to capture sulfur oxide gases from the process gas streams. This paper describes the rationale for selecting the dilute mode dual-alkali system and summarizes design parameters. Start-up problems and their solutions are also discussed.

Jan 1, 1992

By James G. Tilton

Subsidence resulting from mining operations, has been the object of sporadic study for many years. Reports have shown that subsidence has ranged from minor settlement detected only by precise measurements to great slips where buildings are destroyed, roads disrupted, and large fissures opened at the surface. For years, a controversy has raged over the question of whether there is a positive or negative angle-of-draw. None of these questions can be given a flat answer for the variables controlling, subsidence are infinite. Generalizations can be made for various situations and areas but some means of control must be executed.

Jan 1, 1966

By Thomas V. Falkie

The title of this talk has brought some interesting responses - even before it was written - from different parts of the country. A geologist from the Western U. S, was deeply concerned with recent layoffs in his profession and the employment situation in general and wondered why "the AIME wasn't doing anything for the benefit of its members." A petroleum engineer in Texas said that a group in his field were studying "professionalism" and their professional status and wondered if there were any words of wisdom for him. A mining engineering professor from the East pointed out that the National Science Foundation did not include mining engineering as one of its recognized fields in one of its equipment funding programs. These are just a few examples of reactions received to date, but they serve to illustrate the broad image that the title has meant to various people. Actually the term profession is defined by Webster as "a calling requiring specialized knowledge and often long and intensive academic preparation." The word encroach means "to enter by gradual steps or by stealth into the possessions or rights of another", or "to advance beyond desirable or normal limits." The intention of this paper, as originally conceived and requested by the program chairman, was to combine those two words literally and talk about how the professional standing of mineral engineers is being eroded from people outside the profession. But the amazing preliminary response suggests that it may be timely to broaden the discussion by including some comments about professionalism in general. In the paper the terms "mineral engineer" or "mining engineering" are used frequently, but it should be clearly understood that much of what is said is valid and is intended for all fields covered by SME and perhaps for AIME in general.

Jan 1, 1972

By Thomas L. Kesler

Lithium raw materials usable with present technology consist of pegmatite ore and surficial evaporite brine. Those advantageously located now supply world markets. Materials of similar grades and magnitude, but less favorably located, will come into production as present sources are depleted and markets expand. Some of these potential supplies have been explored, and are reserves in the sense of known availability and quality. Reserves herein are of two classes, those proved by close drilling and assaying, and those of only probable status because their scale and grade are unsystematically indicated. Possible resources include similar materials whose bulk can only be inferred on indirect evidence. All figures apply to total materials in the ground. No allowance is made for losses in mining, evaporation, beneficiation, or chemical processing.

Jan 1, 1977

By Chinmay Shingote, Robert Visintainer, Renjie Ke, Jaikrishnan R. Kadambi, John Furlan

Hydrocyclone separators are widely used in various industrial applications in the oil and mining industries to sort, classify, and separate solid particles or liquid droplets within liquid suspensions, which are considered to be multiphase systems. Numerous valuable studies have been conducted in recent years to investigate the flow fields inside hydrocyclones. However, much of the information regarding the performance of cyclones in the literature has limitations and much of it cannot be considered as completely applicable to most real-world applications; many of the studies investigated the flow fields within extremely simplified hydraulic designs that are not representative of the complex geometries or large sizes which are typical in industry. Therefore, in this study, the two-phase flow system inside the actual hydraulic geometry of a milling circuit hydrocyclone is explored with the aid of both computational and experimental techniques (particle image velocimetry (PIV)). More specifically, the flow field with an air core has been investigated. In addition, the air-liquid two phases flow in a hydrocyclone might cause some challenges on both the computational and experimental sides. Two turbulence models are utilized in the numerical calculations: the Reynolds stress model and large eddy simulation. The computational studies are mainly focused on the local flow behavior and the prediction of the dimensions and shape of the air core. Different section planes of hydrocyclone are selected as planes of interest and divided into several fields of view (FOV) for PIV measurements. Two-dimensional experimental velocity vector maps are obtained in each of the fields of view. The computational results are validated globally using pressure and flow rate readings at the boundaries and locally by comparison to the PIV velocity vector maps and profiles.

By A. L. Mular

Si define la simulación digital y las técnicas de simulación son revisadas. La metodologia tipica conlleva la selección de modelos, el ajuste o reajuste de los datos primarios, la selección de una estrategia de acoplamiento, la valoración de la precisión del modelo en un sentido estadistico, y el desarrollo de estructura de simulación ejecutiva. La simulación sirve de ayuda para los ingenieros de procesos para evaluar la viabilidad de un esquema de flujo propuesto y el efecto de la modificación de un flujograma ya existente. Por otro lado, la simulación juega un papel importante en la optimación "off-line" y en la evaluación de estrategias de control de circuitos alternativos. Son presentados varios ejemplos para ilustrar estas utilizaciones para la simulación, incluyendo aplicaciones en los circuitos de trituración, circuitos de molienda y circuitos de flotación. Es de opinión de los autores que, dentro de la próxima década, las plantas de proceso de minerales serán estudiadas rutinariamente a través de una simulación digital durante las etapas preliminares de diseño. La simulación constituirá un importante componente en la toma de decisiones de un proceso.

Jan 1, 1982

By C. L. Pillar

In many cases, substantial time may elapse between the exploration stage and a serious detailed planning stage which has the objective of putting a mineral property into production. This is always true where properties change ownership and new partners are brought in for joint venture situations. Such conditions make it imperative that the recording of complete and accurate geological data for the property is done during the active part of the exploration phase and accomplished by competent geologists and engineers. This work should not be left to helpers and technicians. Furthermore, it should not have to be redone years after the actual drilling was accomplished, when either those involved have parted company or those present have lost the touch and feel of their part of the exploration program and must rely on a memory sketchy in detail, at the best. All of this emphasizes the importance of thorough geological evaluation and reporting during the exploration program. To evaluate and comment on the application of geological data by a mine planning department, we must assume (1) that sufficient diamond drill holes have outlined the existence of a potentially economic ore deposit, and (2) that the next step is to obtain the required information to allow a detailed feasibility study. This paper will comment on: 1. what types of geological information are required, 2. how it can be obtained, and 3. comments on the application of this information by the mine planners.

Jan 1, 1973