Search Documents

By S. G. Britton

Microcomputer analysis has long been a technique for engineering professionals to improve the theoretical and practical design of continuous mining systems. Such work has been typically composed of modeling observed events and then introducing a variety of known elements with predicted results to compare against the results of the model. Programs written in BASIC, Cobol, Fortran, or other language dominated such efforts. These programs have taken years to develop and prove out. This paper explores a new management tool used at TMC on a daily basis to track and improve continuous mining systems through the use of microcomputers and Lotus 1-2-3 software. By analyzing data provided by section foreman, shift foreman, and maintenance personnel against predetermined goals, new production targets are developed, weaknesses in the current mining systems are identified, and the results of changes are measured. The results of this system on the productive output of TMC systems are on the order of ten percent improvement.

Jan 1, 1991

By D. Newman

Ground control is critical to the success of a safe and productive underground stone mining operation. The primary focus of the ground control engineer is the stability of the roof or back; development and benched pillar stability; stability of the sill pillar between vertically adjacent mining levels; and floor stability. Roof stability begins with the selection of a stable back horizon based on the presence of a thin shale parting, stylolite or other discontinuity from which the production shot can easily peel away, leaving a stable back stratum. Bed thickness, fracture spacing, jointing and the material properties of the roof strata control the room width; the decision whether to bolt the roof; the bolt length, type and diameter; and the spacing of the roof support. Horizontal stress controls the header and crosscut azimuth. The mine operator should avoid driving perpendicular to the maximum horizontal stress direction. Where this is unavoidable, narrowing the opening width, narrowing pillar centers, increasing the support density and using three-way intersections are alternatives to remediate shearing along the roof-rib interface. Stable pillar dimensions depend upon the interaction of the vertical stress resulting from overburden thickness and multiple-level interaction of overlying level or levels; the mining height during development and the final mining height after floor shots are taken during benching; the presence of faults, folds or joints passing through the pillar; and limestone lithology, recognizing that the presence of oolitic bands, shale partings, joints and bentonite beds creates zones of weakness that can destabilize an otherwise competent pillar. Floor stability is typically not a significant issue for underground stone mines because the bearing capacity of the stone typically exceeds the vertical pressure transferred through the pillar. However, floor heave can be a ground control issue where shale partings, moisture-sensitive strata, weak stone bands or horizontal stress is present. Roof stability and pillar stability problems can be initiated as the floor heave enables the pillar and roof to settle. To illustrate these ground control issues, this paper presents four case histories that are a mix of ground failures and successful mining. The focus is on the geotechnical data required for roof, pillar and floor design and stability analysis.

Jan 8, 2017

By R. S. Datta

In the article "Concentration of Oil Shale,"(1) Dr. N. Arbiter stated, "One of the major factors in the delayed utilization of oil shale as an energy raw material is the low grade or content of hydrocarbon (kerogen) in oil shale as compared with coal and even more so to the liquid and gaseous fuels. " When the availability of high-grade deposits decreased, mineral industries started adopting prebeneficiation procedures for the low-grade deposits. This practice, which is becoming standard in these other industries, has been largely overlooked by the oil shale industry in its drive to produce oil from oil shale. If a major portion of this mineral matter can be removed, there can be potentially large savings in the capital and operating costs of oil shale retorts. Moreover, the environmental impact, associated with recovering the shale oil, could be reduced considerably. In 1980 Roberts & Schaefer Resource Service (RSRS) completed successfully the first set of demonstration runs with a 20-ton oil shale sample from Cathedral Bluffs (C-b tract), Colorado. This relatively low grade (~12 gpt oil content) oil shale was beneficiated applying the Dutch State Mines Heavy Medium Cyclone process. (2)

Jan 1, 1985

By B. Anameric

Considerable effort has been directed towards understanding the carbothermic reduction mechanisms of self-reducing, fluxing dried green balls to produce pig iron nuggets. Given the geometry of the situation, some investigators believed that the shrinking core model was applicable. Hence, this study involved investigation of the applicability of the shrinking core model to pig iron nugget production. The experiments involved heat treatment of dried green balls utilizing either a laboratory-scale resistance box furnace or a gas-fired muffle furnace at various furnace temperatures and residence times. The products were analyzed for the following: (i) preferred reaction pattern, (ii) distribution of the metallized areas, (iii) % iron content variation in the pig iron nuggets from surface to center, (iv) carburization pattern and (v) physical and chemical properties of the pig iron nuggets. It was determined that the reduction of iron oxide occurred simultaneously throughout the sample and not beginning at the surface and propagating inward; thus the shrinking-core model was not applicable. Heat transfer and gas diffusion from surface to center were not the rate-limiting steps for reduction and carburization reactions.

Jan 1, 2011

By J. Y. Lee, J. Kang

"A selective chlorination process using cuprous chloride (CuCl) was investigated for producing high-grade chalcocite (Cu2S) from chalcopyrite (CuFeS2) feed. The chalcopyrite feed was reacted with CuCl in the presence or absence of sulfur (S) at temperatures between 900 and 1,100 K for five hours under an argon gas atmosphere. The experimental results indicate that iron (Fe) was selectively removed from the chalcopyrite feed as ferrous chloride (FeCl2) at 1,100K and the mass percentage of Fe thus decreased from 31.5 percent in the feed to less than 0.05 percent in the residue, under certain conditions. As a result, high-grade Cu2S was obtained from chalcopyrite in a single step. This new selective chlorination of chalcopyrite using CuCl as a chlorinating agent is therefore feasible for producing high-grade Cu2S.IntroductionCurrently, blister copper (Cu) is commercially produced from sulfide ores by pyrometallurgical methods. These methods entail matte smelting and converting, with the removal of iron (Fe) and sulfur (S) as slag — mainly Fe2SiO4 — and sulfur dioxide (SO2) gas, respectively.In the pyrometallurgical method, as shown in Fig. 1 (Schlesinger et al., 2011), Fe is removed through two steps at high temperatures of around 1,500 K to reduce the loss of Cu during slag formation. However, the slag still contains 1 to 8 percent Cu. Therefore, Cu in the slag is recovered by slag treatment processes, after which the concentration of Cu in the slag decreases to around 0.4 to 1.3 percent. Although Cu is recovered, the slag that had undergone the treatment processes is difficult to use as a feedstock for ironmaking owing to the small amount of Cu remaining in the slag (Schlesinger et al., 2011).In addition, large amounts of SO2 gas are generated by the oxidation of S in the current Cu production process. The SO2 gas generated is captured and used to produce sulfuric acid (H2SO4). However, despite the development of SO2 gas-capture technologies, the emission of SO2 gas is still a problem in terms of environmental considerations.Several studies had been carried out in the past to overcome the drawbacks of the current process. The extraction of Cu from sulfide ores using a chlorination process is one alternative that had been investigated by several researchers. Most chlorination processes used chlorine gas (Cl2) as a chlorinating agent at temperatures between 573 and 1,023 K under an inert atmosphere (Donaldson and Kershner, 1962; Olsen et al., 1973; Kumar, Li and Warren, 1985, 1987; Kanari et al., 1999; Kanari, Gaballah and Allain, 2001)."

Jan 1, 2017

By Keith Olson

In the heart of Appalachia, where coal mining has shaped communities and economies for generations, Bluefield State University (BSU) has made a landmark decision to reestablish its mining engineering technology program. This move comes at a critical juncture for both the university and the mining industry, which faces significant workforce challenges amid evolving technological demands and an aging professional demographic. The program’s revival represents an educational initiative and a strategic response to industry needs and regional economic development. Nestled in the mountains of southern West Virginia, BSU has a storied history intertwined with the region’s mining heritage. The institution’s decision to bring back this specialized program after a hiatus of several years signals a renewed commitment to serving both regional industry demands and providing career pathways for students in an area where the cyclical nature of resource extraction economies has often limited economic opportunities. “This program’s return reflects our deep understanding of this region’s needs and our commitment to preparing graduates for meaningful careers that support our local industries,” said Darrin Martin, president of Bluefield State University. “We’re bridging the gap between education and industry with a modernized curriculum that addresses today’s mining challenges while preparing for tomorrow’s innovations.”

Jun 1, 2025

By Robert A. Blake

Introduction Sulfide copper, zinc and iron concentrates are recovered in the 5000 ton per day flotation plant operated by Cities Service Company at Copperhill, Tennessee. The heavy-sulphide ore is first ground to 50 pct. minus 200 mesh and a bulk concentrate floated. The bulk concentrate, over 60 pct. of the ore weight, is reground to 72 pct. minus 200 mesh and then treated in a selective flotation circuit to recover copper and zinc concentrates. The tailing of selective float is the iron sulphide material source for the manufacture of sulfuric acid and iron sinter. The valuable minerals in the ore are chalcopyrite, marmatitic sphalerite, pyrite, and pyrrhotite. A typical mineralogical analysis will be found in table 1. A typical material flowsheet will be found in figure 1. Shown in the flowsheet are a scavenger float on the bulk rougher tailing and a copper-talc separation unit. At times a lead-copper separation circuit has been run.

Jan 1, 1971

By J. Seiter

Mining has always been among the most hazardous of occupations, and with the increasing demand for coal and minerals, safety in mines assumes even greater importance. Worldwide, underground miners are being exposed to noise and respirable dust hazards associated with roof bolt drilling. These hazards are now being understood to cause irreparable damage to the health of miners. The objective of this research was to discover if a Polycrystalline Diamond Cutter (PDC) drill bit generates less respirable dust and hazardous noise than a competing Tungsten Carbide (WC) bit, in dry vacuum drilling. In order to control the drill parameters the drilling tests have been conducted in a laboratory setting. The results were met by determining the quantities of dust and noise generated using each drill bit and analyzing those levels by using monitoring devices and software to collect the data. This paper includes information on experiment setup, equipment used, drilling parameters, and data collected. The test results suggest that there are noticeable trends that the PDC bits produce less dust than WC bits but more testing is needed to substantiate these trends.

Feb 23, 2014

By Paul W. McGann

This paper presents a methodology for long-range studies of petroleum supply, to meet projected demands, that involves modifications of procedures used previously. This paper continues a series of papers on this general topic in the AIME, the most elaborate recent one being that by Warren Davis given in February 1958. The procedures considered here begin with the assumption that the governmental framework of regulations and taxes remains fixed- but that price changes. After .these procedures have been reviewed, the effects of changing certain governmental controls, will be considered in order to judge their potential effects on future supply. This is an essential step because controls cannot be expected to' remain static in a situation changing as much as the petroleum. industry and because such changes are within-the scope of alternative ways of adjusting to impending problems. The first procedure begins with: a) trends in drilling success, b) relation between field income from oil and gas and footage drilled, c) declines in capacity from production, d) trends in capacity of new and producing wells, e) all monetary values are in constant 1958 dollars, and f) target amounts of domestic crude petroleum production. 'From these components projections are obtained of: 1) numbers of future producing wells required, 2) footage drilled, 3) new wells drilled, 4) crude oil found, 5) capacity of producing wells, 6) completion costs, 7) finding costs, 8) production costs, and 9) average wellhead crude oil price consistent with the footage-field income relationship.

Jan 1, 1960

By W. G. Lawrence

The rapid development of science and technology in Russia has been the result of well laid plans since 1918. At that time the Institute of Silicates was established is Moscow and later the establishment of similar more specialized institutes for the study of cement, glass, refractories, construction ceramics, electrical ceramics, building materials and asbestos provided the necessary research facilities for studies related to all types of ceramic inorganic materials. The' Institute of Ceramics and the Institute of Silicate Chemistry, Academy of Sciences, USSR, were founded in Leningrad. The work now going on in these various research' institutes covers every branch of silicate science and ceramics The impetus behind such establishment of special¬ized laboratories is no doubt due to the 5-year plans and the necessity of improving the scientific knowledge regarding the materials being used and the products being manufactured.

Jan 1, 1960

By Diogo Peixoto Cordova, Italo Gomes Gonçalves, Andre Cezar Zingano

The top-down extraction sequence in the sublevel open stope method relies on rib pillars to support excavations, making pillar and stope stability crucial for controlling dilution. This study introduces an integrated methodology using a genetic algorithm to optimize the layout of open stopes and rib pillars while considering both economic and geomechanical performance. The methodology incorporates user-defined parameters such as the minimum size of stopes and pillars, maximum accepted dilution and acceptable percentage of pillar failure. A profit function that attributes economic value to the geometric configurations, including geomechanical performance, is employed. The geomechanical performance, assessed using numerical models in FLAC3D, includes the average percentage of pillar failure and potential dilution. The study was tested on a mining panel from an underground gold mine using a top-down mining sequence. The optimization achieved an 8 percent increase in net profit compared to the traditional engineer’s design when 70 percent hangingwall support efficiency was assumed, and a threefold reduction in pillar failure percentage. When no hangingwall support was considered, the net profit increase reached 22 percent. These results demonstrate that the proposed methodology enables integrated optimization, balancing mining costs with geomechanical performance and reducing the need for secondary support compared to traditional methods

Nov 1, 2024

By Gregory Rumbaugh, Christopher Mark

Recent pillar collapses have caused five large airblasts in underground U.S. limestone mines. One of these events injured three miners, but all of them put many other miners at risk. To better understand the hazards, Mine Safety and Health Administration (MSHA) conducted a comprehensive review of the international literature on airblasts. More than 40 airblast cases have been documented, in a wide variety of minerals. Experience shows that miners that are in the direct path of the air as it moves towards the mine exits are at the greatest risk. The paper describes a risk management methodology that can be used to evaluate the level of hazard throughout the mine and aid in the selection of controls to reduce the risk. The paper concludes with a detailed case history of an actual pillar collapse and airblast.

By B. Eiter, M. Barham, T. Bauerle

Fatigue-related risk is a persistent safety concern for the mining industry. However, fatigue and sleepiness are often treated interchangeably, which can lead to confusion and potentially less effective reduction of safety risk. To provide clarity, we present an overview of similarities and differences between work-related fatigue risk and sleepiness including definitions, theories, measurements, and mitigation strategies. As a supplement, a summative visual model which highlights these similarities and differences is presented. Expanding industry knowledge in this area will assist safety professionals in crafting more targeted risk management practices appropriate for work-related fatigue risk, sleepiness, or both.

Feb 1, 2023

By T. Kelly

The Cannon Mine is located in Chelan County, near Wenatchee, Washington, at the eastern foot of the Cascade Mountains. The mine is situated about two miles from the Columbia River, in the arid Columbia River Valley. Two hydroelectric dams provide electricity for the area, the Burlington Northern Railroad has a switch yard and loading facilities in Wenatchee. Approximately 25,000 people live in the area. The principal industry is fruit farming. Underground mining techniques are used to provide feed for a 2,000 tpd flotation concentrator at the site. The techniques are low- cost, high productivity methods which allow for a high extraction rate along with a high rate of recovery of the minable reserve.

Jan 1, 1986

By J. F. Colinet, W. R. Reed, J. D. Potts

Dust surveys were conducted at six underground coal mines to determine if deep-cutting practices expose face workers to higher levels of respirable dust. The surveyed mines were able to successfully mine deep cuts without significantly increasing the dust exposures of face workers. In general, all of the selected mines exercised good dust control practices by maintaining water sprays, scrubber airflows, proper curtain setback distances and providing sufficient airflow to the active faces. For exhausting face ventilation, field data indicate that scrubber airflow is the most important factor for controlling dust. Data collected for this study indicate that 20-mesh screens should be cleaned for every 12.2 m (40 ft) of advance, because 22% of the deep cuts surveyed for this study experienced a 20% to 35% decrease in scrubber airflow over the course of the cut. For blowing face ventilation, field data and past research indicate that dust control is aided by maintaining a proper curtain-to-scrubber airflow ratio of 1.0 (measured before scrubber activation), as well as a curtain setback distance that allows the miner operator to stand at the mouth of the curtain for the entire cut. Dust levels on the bolting faces did not appear to be affected by the longer cycles associated with deep-cut mining when good ventilation practices were used.

Jan 1, 2011

By Fitzhugh T. Lee

Results from the first part of a two-part investigation of the stability of highwalls in open-pit coal mines in the Paleocene Fort Union Formation of the western Powder River Basin of Wyoming and Montana indicate that these highwalls are subject to time-dependent deformation. Field investigations and laboratory physical properties tests of coal and overburden rocks suggest that several factors influence highwall stability. Some of these factors are rebound of overconsolidated rocks, desiccation, water, orientation and spacing of fractures, and strength and deformation properties. Factors of safety for a typical highwall in the study area (calculated by the finite element method) may be less than 1.0 when open fractures are present and the highwall has degraded. Although it is concluded that most open-pit highwalls in the Fort Union Formation within the study area have adequate short-term stability, these highwalls do deteriorate and become progressively less stable. Because of this, postmining failures are common and stability conditions could become critical if mining were delayed and then resumed after a period of several months. The second part of the investigation will utilize field measurements of rock-mass properties and instrumentation of actively mined highwalls to obtain data for comparison with the results of the initial investigation. Because the height of highwalls will increase as the more shallow coal is exhausted, these data will also be used to predict the behavior of slopes higher than those presently found in the western Powder River Basin.

Jan 1, 1977

By W. R. Sharp

The ability to target, delineate, excavate, and produce local resources is essential to the establishment of man's long-term presence in space. Many procedures and equipment utilized to mine resources here on Earth may be directly applicable on the lunar surface, while others may need extensive redefinition and development. This paper compares, for a lunar base, the alternative of burrowing into and below the lunar surface with that of surface mining. A conceptual underground mechanical excavator is presented.

Jan 1, 1991

By Kenneth N. Han

The effect of anions such as sulfate, chloride and nitrate on the solubility of rare earth element (REE)-bearing phosphates and fluoro-carbonates was examined using relevant thermodynamic data. The study found that these anions have significant influences on the overall dissolution of REEs from various sources in the aqueous media.

By Frank Pollard

The Australian coal industry over recent years has experienced the situation whereby exploration and mine development are moving into geographical areas where the coal seams have never been mined to any extent in the past, if at all, and particularly where there is no history of experience in preparation of these seams. Additionally, the demands have been such that the development of a mine up to production stage should proceed with minimum delay. This is a situation which is of some importance and concern, in view of the coal quality requirements now experienced within world markets which can only be met, in most cases, by careful preparation. Costs are such that the preparation plant should operate as required by the situation and with maximum efficiency, which means that laboratoty information of breakage and washability characteristics which are required for preparation plant design should be accurate and available as soon as possible, even to a certain extent during the progress of the exploration.

Jan 1, 1981

By Patricia Petty

If enthusiasm is a requirement, the coordinator of the Total Concept program is a dynamic, exciting leader with a lot of potential to keep the program a vital and progressive effort for many years. Art Meyer is entering his third year as the leader of the Total Concept. He is using his years of experience in the industry to emphasize the basics required for the course, and has also instituted new programs. Meyer began his career, after graduation from CSM as geological engineer in 1950, with St. Joe Lead. He held other responsible positions with Amax and Rocky Mountain Energy. He can answer any questions that may crop up or find the right resource person for those questions. Additions to the 18-year-old curriculum instituted since Meyer became coordinator are the study of industrial minerals and strategic minerals. The industrial minerals portion of the course includes visits to a major sand and gravel operation, in addition to lectures on the subject. Much of the strategic minerals requires study and lectures, since Colorado is not a big production state in these commodities. How does the director arrive at new additions or deletions to the program? "It's very simple," he says. "We listen to questions posed by the students, recommendations by industry people who know what is important, and feed-back from course alumni." Alumni feedback from this course has been extremely gratifying, according to Meyer. Other ideas are constantly surfacing, ideas that will be implemented as time and resources permit. One of the most gratifying results of the Total Concept program from an alumnus was the development of a complete teacher and student package by John Christiansen, a teacher at Cherry Creek High School near Denver. The course so excited Christiansen that he envi¬sioned an energy and minerals course to fill a perceived gap in science education on the high school level. The draft package was so attractive that it was sponsored and the publication costs guaranteed by the Society of Mining Engineers. Today, under the leadership of the Mineral Information Institute, the package is in use in several states and has gained enthusiastic acceptance. Other alumni have launched their efforts to broaden the scope of the existing science education by instituting courses or special seminars. One recent alumnus, Dick Will, class of 1984, who was sponsored by the Denver Mining Club, is conducting a science seminar based on his experiences with the Total Concept program. Meyer will be speaking at this seminar, as well as other industry speakers from the SME GEM Committee Speaker's Bureau. Jane Dianich, another alumna, brought her students at Kent Country Day school, also near Denver, into the mainstream of resource education by taking them on abbreviated field trips similar to those she experienced while in the program. She also has been a vocal supporter of the organization and available to speak to other teachers on the value of the experience. George Wright, of the Lake School and a second sponsoree of the Denver Mining Club, admits he came into the program because the six credit hours given toward his continuing education requirement were attractive. He then stayed on to become an ardent advocate of the mining industry. In his own words, "I'm a convert." Wright has developed a slide presentation and has lectured to teachers and students as well as presenting his views to the Denver Mining Club. He has also indicated a willingness to participate with other organizations who need speakers. The value of these speakers and teachers is obvious, according to Meyer. "They represent a respected segment of the public and are not too `tainted' by association with an industry that is too often under criticism from various groups. They represent, in effect, a citizen's advocacy of the industry, which is an invaluable asset to us all." One of Meyer's concerns about the program is that the out-of-state student rate attendance is declining. He is hoping that more AIME sections around the country will become involved in the scholarship program of the Total Concept. Total cost is about $1200 per student. "The rewards to their sections could be tremendous, with the same kind of participation we get here with speakers, citizen advocates, and interested persons," he said. Teachers say that the course improves their teaching and knowledge in a number of subjects including biology, history, economics, career planning, environmental data, science, math, geography, physics, and chemistry. The recent interest in hazardous waste management has sharpened the desire to learn more about this. And Meyer foresees another segment of the course to emphasize this subject. "One of the most valuable resources we have is the field trip program. The course would probably be meaningless without this opportunity to get out into the field where these folks can see what actually happens. George Wright, for example, was amazed at the very small amount of area actually involved in the mining operation - something contrary to what he had heard in the past." The 45 students are taken by van on eight trips, one each week, and the long trip to Colorado's Western Slope. During this long adventure, the students visit underground mines, including CSM's Edgar, open-cut and underground coal mines, precious metals mines, and oil shale properties. They also have opportunities to meet with mine personnel at each of these stops. These field trips fill another function. Living together and exchanging ideas helps the teachers come up with new concepts for the classroom work - expanding their horizons. "As long as we have a mining industry, this effort will continue to grow," Meyer said, "and will fulfill a need within the public education and public relations area of the industry. We need the support. I have dozens of comments from teachers who attest to the value of this program. They understand. The mining industry must continue to do its part."

Jan 3, 1986