Search Documents

By E. A. Metz

Silicon dioxide, silica, is the most common oxide in the earth' s crust. The health effects of silicon dioxide dust have been known since Biblical times. Agricola's book, published in the mid 1500's on occupational medicine, described a lung disease that afflicted miners. He observed a disease in miners that caused shortness of breath, coughing and wasting. Add fever, chest pains and fatigue and we have the current symptom complex of silicosis. As we approached the 21stcentury, the Labor Department began an aggressive campaign to combat silicosis-a preventable disease. Unfortunately, many publications do not clearly differentiate the polymorphs of silica known to mineralogists. Crystalline silica, i.e., alpha quartz, tridymite and cristobalite need to be considered differently from the amorphous forms of silica. Freshly fractured surfaces of the silica and host specific responses will be examined. Recent research focuses on the biologic interactions of free radicals generated by mineral particles. This results in cell injury and DNA damage, in turn leading to fibrogenesis and possibly carcinogenesis. In addition to particle-cell interactions, emphasis is given to lung defense mechanisms.

Jan 1, 1998

By John Davis Morgan

The uncertain world conditions of the present time require that the United States be prepared to meet: a. all-out nuclear war with attack on the United States b. limited wars (anything smaller than (a.) c. political, economic, and/or psychological warfare. Our present position as a major world power derives in large measure from our free institutions and our great industrial productivity, and our productivity in turn depends on an ever-continuing flow of raw materials from the earth - metals, minerals, fuels, and agricultural products. The United States, with only about 6% of the world's population, uses from one-third to two-thirds of the world's annual supplies of 'most metals and minerals. The United States strategic materials stockpiling program is designed to enhance our national security posture: as stated in the preamble of the Stock Piling Act, to decrease and prevent wherever possible a dangerous and costly dependence of the United States upon foreign nations for supplies of strategic and critical materials in times of national emergency. In times past, the Good Lord himself has ordered some stockpiling. The Book of Genesis in the Bible tells how Pharaoh of Egypt was directed to set aside one-fifth of the produce of the land in each of the seven good years to meet the needs of the seven bad years that were to follow: this would be a stockpile of about two years? normal use. Our cultural heritage often reminds us of the wisdom of stockpiling, as in the case of the stories about the provident squirrels that gather their nuts in an orderly manner in the f all to prepare for the winter's cold. And the old proverb about a bird in the hand being worth two in the bush points out clearly the value of something that is directly at hand.

Jan 1, 1960

By Rolph Linder

It is generally known and accepted that the efficiency of the blast furnace process, expressed by the symbols specific production and coke consumption, is influenced by a large number of variables connected to the type of burden, the alloy contents of the produced iron and the conditions of production as composition and preheating of the blast, the furnace heat losses and the possible use of fuels added on the tuyere level. It is furthermore obvious, that the coke consumption of the process will be influenced by specific production which could be said to be the result of two counter-acting influences. With high production, realized through intensive blowing, the passage time of the ore through the furnace is shortened leading to a decrease of the indirect reduction taking place in the upper part of the shaft within the temperature range of 300 to 1000°C. Simultaneously the external heat losses (constant in time) will be smaller calculated on each ton of iron and the resulting change in coke consumption will be the effect of both those influences. It is certainly of interest to be able to predetermine the effect of those variables before a change in the production practice is carried out.

Jan 1, 1964

By J. D. Forrester

I have availed myself of the opportunity to prepare, and to give this talk because, as incumbent Chairman, I am directed by the Bylaws of the Council of Education to make an Annual Report of the Council activities which have transpired during the past year. In addition, and inasmuch as I have this captive audience, I am taking the liberty to express also some beliefs I hold about various other elements of Mineral Industry education. First, my report is that constructive progress has been achieved in the Council of Education during 1960-61. These advancements have been particularly notable through projects carried on by the Committee on Meetings and Programs, by the Student Chapters Committee, by the Accrediting Affairs Committee and by the Committee for Securing Better Representation of Mineral Industry Colleges. I believe each of these groups will report concerning details of their respective programs at the Business Meeting of the Council. On the other hand, not as much has been done in some areas of work as I had hoped would be the case when I took office as Chairman last February. Let me make clear that these delinquencies, for the most part, have resulted through my ineptness in handling of affairs; they are not caused by the failure to perform various assignments which I have given to council members.

Jan 1, 1961

By Donald C. Violetta

During 1963 more than 200 million tons of coal was consumed by the public utility industry. Ash residual, from the burning of this coal has caused disposal problems. In order to prevent air pollution, dust collection systems have been installed to suppress the fine ash emitted from boilers before it is discharged into the atmosphere. The collected ash, called fly ash, must be removed from the dust collection facilities and disposed in some manner, usually at a substantial cost to the utility. Many years ago fly ash disposal was not a serious problem because the demand for power was relatively low and coarse coal was burned on stoker type traveling grate machines. The low burning rates utilized on these grates did not produce large quantities of air-borne coal ash while the mechanics of this system of burning resulted in a clinkered residue of cinders. Both of these conditions resulted in the production of only small quantities of fly ash. As the demand for electricity increased, a method of burning pulverized coal was developed and was introduced to the public utility industry in 1918 at Milwaukee, Wisconsin.1 This method of firing was considered a significant advance in steam electric generation as it (1) permitted the use of coals that could not be economically fired by other methods and (2) has generally resulted in improved efficiency, greater generating capacity and lower costs.2 The utilization of larger generating units using pulverized coal substantially increased the quantity of fly ash which resulted in a' more severe disposal problem.

Jan 1, 1966

To preserve Washington Group International's quality of service in the mine operations area, the company has established a Supervisor Training Program to provide all levels of supervision with the required skills to meet objectives and guarantee consistent, excellent performance for each of our projects. A need developed to establish this training program internationally. The first international training session was held at the APEX San Cristóbal Mine in Bolivia. This paper discusses the program’s development, execution, results, and lessons learned with an emphasis on multicultural environments.

Jan 1, 2007

By Jr. Hawk

The power generation industry may be required to reduce CO2 emissions if regulations related to global climate change are enacted. Coal-fired generation, which emits 82% of the power sector CO2, would be a likely target for CO2 reduction. Compliance with the Kyoto protocol will require a 30% reduction from the projected year 2012 emission level even with moderate load growth. This paper describes an analysis of power industry CO2 reduction options and their costs to assess how a generator would make compliance decisions under a mandatory CO2 emissions reduction program. Carbon sequestration, fuel switching and new plant construction are considered.

Jan 1, 1999

The 28th annual American Mining Hall of Fame Awards Banquet and fundraiser sponsored by the Mining Foundation of the Southwest will be held at the Marriott University Park Hotel, Tucson, AZ on Saturday, Dec. 4, 2010. The Mining Foundation of the Southwest is a nonprofit organization whose objectives are public education about the mineral industries, and recognition of outstanding accomplishments in and contributions to the fields of mineral and fuel resources. Funds are being raised to the support the foundation?s educational programs. Among these is the Educational Outreach Program operated jointly by the foundation and the Arizona Department of Mines and Mineral Resources.

Jan 1, 2010

By Paul T. Allsman

The guiding principle in developing this plan resulted from evaluating potential future markets for oil, the quantity of mineable oil shale and the optimum rate of production comensurate with market demand on the available oil from shale. In addition, the rate of production may depend upon a solution to the problems of scarcity of resources other than oil shale. The rate of production finally will tend to establish the choice of technologies with these limits. The principle components discussed will be: 1) The place of oil shale among the various energy sources and its relative adaptability for use in the area of major consumptive demand. 2) A recalculation of the reserves and their classification on the basis of quantity, grade - gallons per ton, - and physical characteristics principally thickness, overburden and depth.

Jan 1, 1982

By B. J. Timmons

Depending upon which of two letters describing the theme of the session I chose to honor, the subject choices because either one or three. They were: "Applied Research and Exploration and Discovery" or "Applied Research in Exploration and Discovery." The final choice; to partially ignore both of them. That minor difference in meaning may be appropriate here, inasmuch as very minor research/exploration differences may also have profound impacts on discovery. To further set the stage, I consider myself an Industrial Minerals geologist, and more specifically primarily associated with basic construction materials crushed stone and sand & gravel. My remarks will apply primarily to those materials. Therefore, when the discussion instructions included emphasis on beneficial aspects (to name a few): "drill target definition; elimination of ore potential; ore forming environments; alteration studies, and isotope analysis," problems became apparent. Evidently, and although this was a form letter, the drafters of that letter had no idea what was involved in research for a construction materials source. My task may be great.

Jan 1, 1995

By Terry D. Vandell

The purposes of this presentation are: (1) to discuss the actual as well as potential incidents that have caused and that could cause groundwater contamination at uranium in situ leach mining sites and (2) to discuss remedial actions and solutions that have been or that could be implemented in the future to stop or prevent serious groundwater contamination from in situ leach mining in Wyoming?s Powder River Basin. Open pit, underground, and existing and proposed in situ leach uranium mine sites in the Powder River Basin are shown in Figure 1. In situ leach mining or solution mining for extracting minerals in liquid form is a relatively new addition to the list of conventional mining methods currently used to extract uranium in Wyoming's Powder River Basin. Basically, the in situ leach mining method involves: (1) the injection of a leach solution lixiviant (an acidic or basic oxidizing solution) into a uranium-bearing ore body, via injection wells, to complex the contained uranium, (2) mobilization of the uranium complex from the host material via creation of a soluble complex salt, and (3) surface recovery of the solution bearing the uranium complex via production wells. Uranium is then separated from the leach solution by conventional milling unit operations (ion exchange).

Jan 1, 1981

By H. Huang, R. N. Gow

"Previously, Gibbs’ phase rule was applied to mass-balanced EH-pH diagrams for the Cu-As-S-H2O system. Diagrams were generated using the stoichiometry of enargite as a basis. In this study, the calculations were expanded to cover the stoichiometries of three other Cu-As-S minerals (tennantite, sinnerite, and lautite) and compared to enargite. Stability regions within the resulting EH-pH diagrams were found to change with stoichiometry such that a particular mineral would predominate if its stoichiometry was used in the calculation. Solution speciation was also found to vary, with thioarsenate being the best example. This stoichiometric effect helps to explain results reported in the literature and would be difficult to realize if it were not for mass-balanced calculations. INTRODUCTION A comprehensive thermodynamic review has recently been conducted on the aqueous copper-arsenic-sulfur system (Gow et al., 2014a-d). The free energies of over 100 species were collected from various authors and thermodynamic databases to produce mass-balanced EH-pH diagrams, using the thermodynamic equilibrium calculation software, STABCAL (Huang, 2014). The full database was listed and discussed by Gow et al. (2014A). Resulting diagrams were generated for enargite and confirmed with Raman spectroscopy using bulk mineral electrodes in order to identify reactions spectroelectrochemically. Theoretical calculations agreed well with the experimental results under alkaline conditions (Gow et al., 2014a), acid conditions (Gow et al., 2014b), and alkaline sulfide leaching conditions (Gow et al., 2014c). In this study, additional mass-balanced EH-pH diagrams are generated by changing the copper-arsenic-sulfur stoichiometry from enargite (Cu3AsS4) to tennantite (Cu12As4S13), sinnerite (Cu6As4S9) and lautite (CuAsS). Regions for the thermodynamically stable species are shown to change with the four different mineral compositions. Potential leach conditions, both for co-dissolution and selective dissolution techniques, were examined for differences in predominant species according to changing copper-to-arsenic ratios, sulfur compositions, and sulfur oxidation states."

Jan 1, 2015

By LeRoy D. Loy

The coal mining industry must be able to compete with alternate sources of fuel for the utility and industrial customers. If the industry is unable to control transportation costs, either due to government interference, or for other reasons, then mining costs must be kept down. Australia, South Africa, Canada, (and later Colombia) will take larger shares of the export market if mining costs are not kept competitive. The government's environmental regulations must be met without incremental increases in mining costs. Entrepreneurial instincts must be retained by the industry to provide for their investment in the future. What are the Problems with Existing Research? Government funding for coal mining research has been reduced or virtually eliminated. BCR (Bituminous Coal Research) is now a membership- supported organization, but its primary focus has been on health and safety-oriented research. BCR, however, is now attempting to widen its scope and conduct other types of research. There are almost no funds in EPRI's (Electric Power Research Institute) program for coal mining research. Large mining companies do some research for their own purposes and needs, but this is proprietary and therefore results are not shared with the remainder of the industry. The mining industry as a unit is not undertaking productivity (systems) oriented research in any common or cohesive manner.

Jan 1, 1983

By W. Clark Ashby

Productivity is a fascinating concept. Like motherhood or apple pie, we know it as a good thing. Just what it means is not so clear. To a coal miner we assume it means tons of coal hauled from the mine. To the company president it means profit after capital, labor, and other costs have also been reckoned. To the government economist it means output in a balance of payments. What does it mean to the biologist, and can reclamation really be productive? In this paper we discuss productivity from a biological viewpoint, give some yield data for various types of reclamation plantings, and discuss how our demand for or acceptance of differing kinds of productivity is tied up in bigger questions of land use, environmental stability, and resource allocation.

Jan 1, 1981

The implementation of NAFTA in January of 1994 was expected to have small but beneficial effects for the Mexican economy, mostly through increased investment flows. Mexico's mining industry was especially likely to benefit, as mineral investment funds would be diverted to the now safer Mexico and away from similarly endowed but more risky Latin American mineral economies. The results of the past two years have shown that it is governments and macroeconomic factors that influence investment flows, rather than the fine-tuning of trade flows through so called "free-trade" agreements.

Jan 1, 1996

Blast vibrations induce sounds within neighboring residences. A house wide vibration and sound monitoring system was installed in a West Virginia home which was subjected to blasts at varied distances and direction. Eighty-nine blast events were monitored and analyzed for this case study. Fifteen channels of data were collected including three triaxial geophones, one airblast microphone, one uniaxial geophone mounted to the wall of the house (response channel), and four microphones that recorded CD quality sound waves inside the house. Each of these channels was recorded on the same time reference and scale allowing for direct comparison of the waveforms. The response channel signal was easily separated into ground vibration induced and airblast induced movement due to the differences in their times of arrival. This response channel was then compared to the sounds recorded inside the home to determine which component of blast vibration induced the maximum sound response inside the home. Blasts at distances less than 762 meters (2,500 feet) had maximum sound responses from both ground vibration and airblast. While for blasts beyond 762 meters (2,500 feet), the maximum sound response inside the home was caused by ground vibration without exception. When airblast was identified as the dominant sound generator in the house, the peak amplitude of the sound was directly related to the amplitude of airblast. When ground vibration was identified as the dominant sound generator in the house, the peak amplitude of sound was not related to the amplitude of ground vibration. In these cases, sound amplitude was driven by the conditions present in the house such as loose items, doors, and windows creating sudden peaks from falling or slamming. In the same respect, sound amplitudes varied depending on where the sound was recorded. Different rooms generated very different sounds based on the contents of the room. Findings from frequency analysis showed that the frequency content of sounds inside the house were not related to frequency content of airblast or ground vibration regardless of source suggesting that residents would have difficulty determining the source of blast induced noise in their homes.

Jan 1, 2010

By J. Carr

Ring gear and pinions used as the final drive on large metallurgical grinding mills are expected to transmit their rated horsepower reliably for long periods of time. Duty is 24 hrs./ day. Life expectancy of such gear sets is of the order of 20 years; that is, each gear and pinion flank is expected to resist failure by pitting for 10 years. This means that for a dual pinion gear set having a ratio of 18.42:1.0 and a mill speed of 10 RPM, every gear tooth will see 105.12 x 106 surface contact stress cycles and every pinion tooth will see 968.15 x 106 surface contact stress cycles in a 10 year period. The allowable surface contact stress on the gear and pinion is determined by the material hardnesses. The rule being the higher the hardness, the higher the allowable surface contact stress may be.

Jan 1, 1985

By Bo R. Arvidson

High-energy product permanent-magnet materials of rare-earth cobalt alloys are being used in applications where space or weight are at a premium cost. New applications like friction-free bearings are also made possible. However, such magnet materials have not been commercially used in magnetic separators until now due to the high cost for the overall magnetic flux generation relative to commonly used ceramic magnets or AlNiCo magnets. The design of the new high-intensity permanent- magnet roll separator (PERMROLL) takes advantage of the unique properties of rare-earth cobalt magnets rather than just substituting for conventional magnet materials now in use for magnetic separators. Hence, the new generation of high-intensity magnetic-roll separators has some unusual characteristics that make known magnetic separation applications more economically attractive, and even expands the magnetic separation technology area to include applications for which no other feasible methods are presently known.

Jan 1, 1983

By Brendan Donnelly, Jung-Hoon Sul, Lasitha Piyathilaka, Sanghyun Jeong, Benjamin Probyn

The chains of armored face conveyor (AFCs) are constantly in contact with water and wet coal, which results in a significant proportion of unplanned downtime experienced on longwall equipment due to corrosion. While reverse osmosis (RO) is one of the most prevalent water treatment methods for reducing salinity and dissolved solids in coal mining, its impact on the corrosion of the AFC chains has not been well studied. This work studies the direct effects of RO water on the corrosion of AFC chains. Immersion tests followed by surface micromorphology analysis and corrosion indices indicate that the RO water increased the corrosion rate of the AFC chains due to the reduced tendency of preventive films on the chains.

May 1, 2024

By Carl Eschman

Productivity from large walking draglines is primarily dependent on operator skills. This machine may be in operation three shifts a day, 364 days a year, and its output is directly related to coal uncovered and mine profitability. Dragline operators must have highly developed manual skills and be knowledgeable in mine planning and working strategies. When using equipment costing more than $25 million, some formal training is usually required before an operator is allowed to assume complete con¬trol; however, dragline operators rarely receive any structured training before operating these giant excavators. A form of apprenticeship is usually followed where an operator candidate progresses from a groundsman to an oiler position. As an oiler, he is permitted to operate the dragline for short periods under supervision. After apprenticeship, the operator is considered sufficiently prepared to operate the largest, most powerful machine at the mine. The apprenticeship training method has obviously provided the surface mining industry with skilled dragline operators; however, conditions are arising that require a realistic and effective training tool that can be accessed by mining companies. New mines -either planned, under construction, or recently opened in the West-do not have access to a pool of experienced operators and oilers as do Midwest mines. As coal mining activities increase in both the West and Midwest, demand for trained dragline operators could be required in a short amount of time. Also, the more productive techniques along with sound basics of strip mining are sometimes lost in the informal "OJT" training method. Modern draglines are the pacemakers of the strip mine, and are simply too expensive to be used as a training device where lost productivity and susceptibility to damage can directly affect mine output. The Dragline Training System is a logical first step in formally educating or retraining operators. The program, started by the US Bureau of Mines and continued by McDonnell Douglas Electronics Co. under contract with the US Department of Energy, was installed and evaluated at DOE's Carbondale Mining Technology Center in Carterville, IL, last year. It is now being operated by Southern Illinois University at Carbondale. System Description The Dragline Training System addresses specific environments and work practices encountered during an actual mining operation at a midwestern US surface mine. This area was chosen because of its high number of strip mines using large walking draglines. Most draglines in the region are Bucyrus-Erie 1370, 1450, and 2570 models, so the dragline trainer was patterned after the company's 1370 machine. Operating and emergency controls are sufficiently standardized for most large walking draglines, and peculiar dynamics and responses from any specific dragline can be programmed into the computer system. The computer simply prompts the user to select the manufacturer and any peculiar response or rate changes needed. A 46-m3 (60-cu yd) bucket is simulated, but for closer simulation, various bucket configurations can be provided. Dragline Trainer The dragline trainer uses the TV-model simulation technique. A scaled model of the dragline is positioned in a model mine. A television camera is positioned at the operator's theoretical eyepoint, and the view captured is projected into a large screen in full scale. The screen is positioned in front of the operator seated in a full-size cab at Bucyrus-Erie controls. By manipulating the controls, the trainee can operate the model dragline and observe its reaction in the television display. In addition to housing dragline controls and consoles, the wooden, oversized cab contains the digital computer, terminal, video recorder and monitor, power switch box, air conditioner, and has enough room for the instructor and five student observers. The 50:1 scaled dragline model contains servo-controlled functions for hoist, drag, swing, delta swing, and longitudinal and lateral position. The delta swing provides bucket lag during swing and a realistic pendulum action when the swing is terminated. The over-responsive second order servo system is designed to provide hoist, drag, and swing rates exceeding present draglines. In all cases, position servos are used for better control and sta¬bility. The normal rate operation of an actual dragline is computed for the specific machine and presented to the servo amplifiers as iterative position commands increasing or decreasing

Jan 6, 1982