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By L. Yuan, J. H. Rowland, R. A. Thomas

"Hydrogen (H2) gas released during battery charging can result in cross-interference for carbon monoxide (CO) sensors used for early fire detection and compromise the integrity of the mine atmospheric monitoring system (AMS). In this study, a series of laboratory-scale and full-scale experiments were conducted to evaluate the responses of different CO sensors to H2 gas. In the laboratory-scale experiments, constant H2 concentrations in the airflow, from 100 to 500 ppm, pass through sensors. While in the full-scale experiments, increasing H2 concentrations generated as a byproduct from charging the batteries at the battery charging station rise to the sensors under different ventilation scenarios. The H2 concentrations at the CO sensor location were measured using H2 sensors and were correlated with the CO sensor response. The effects of ventilation and sensor location on the CO sensors responses were also analyzed. The results of this study can help mining companies to select appropriate CO sensors and improve the deployment of these sensors to ensure the safeguard of underground miners. INTRODUCTION As many types of battery-powered mining equipment such as scoops and shield haulers are used in underground mining operations, charging stations are required to charge the equipment batteries. These batteries are of lead acid chemistry. A safety issue exists with the battery charging stations as all lead acid batteries produce flammable H2 gas during the normal charging process. Overcharging or excessive heat can quickly cause batteries to produce even more H2. If H2 is not appropriately diluted or dispersed, it builds up, and the risk of fire and explosion increases. Mine Safety and Health Administration (MSHA) regulation (30 CFR Part 75.340) requires that battery charging stations should be housed in noncombustible structures or be equipped with a fire suppression system. When a fire suppression system is used, the battery charging stations must be ventilated with intake air that is directed into a return air course or ventilated with intake air that is monitored for CO or smoke using an AMS. The monitoring of intake air ventilating battery charging stations should be done with sensors that are not affected by H2."

Jan 1, 2018

By R. Michael

Among underground coal miners, hearing loss remains one of the most common occupational illnesses. In response, the National Institute for Occupational Safety and Health (NIOSH) conducts research to reduce the noise emission of underground coal-mining equipment, an example of which is a roof bolting machine. Field studies show that, on average, drilling noise is the loudest noise that a roof bolting machine operator would be exposed to and it contributes significantly to the operators? noise exposure. NIOSH has determined that the drill steel and chuck radiate a significant amount of noise during drilling. NIOSH and the Corry Rubber Corporation have developed a bit isolator that breaks the steel-to-steel link between the drill bit and drill steel and a chuck isolator that breaks the mechanical connection between the drill steel and the chuck. This effectively reduces the noise radiated by the drill steel and chuck and reduces the noise exposure of the roof bolter operator. The paper documents the evolution of the bit isolator and chuck isolator. Laboratory testing confirms that production bit and chuck isolators reduce the A-weighted sound level generated during drilling by 3.7 to 6.6 dB

Jan 1, 2010

By Nathaniel Arbiter, Robert R. Beebe

The U.S. mining industry - once world dominant and largely independent of foreign sources for most major commodities - has today lost this position, with little likelihood of regaining it. But even though Business foretold The Death of Mining four years ago, the current outlook is less pessimistic because of drastic restructuring of the industry; a major reduction in its labor force, with resulting large increases in productivity; and introduction of improved technology. In the face of this clearly changed climate for domestic mining, it is important to examine the role of the development and research establishment in the industry's future, which raises a complex set of questions: 1. Where and to what extent can new technology assist in the continued survival of the industry ? 2. What is the past record of the research establishment in developing new technology; and what is the industry's record in supporting and adopting it ? 3. In the light of these records, and of the drastic cuts in both research staffs and expenditures, what areas should be the most important targets for new technology? New Technology vs. Old A1 though mineral processing's origins can be traced back through five or six millennia, its modern structure is about 200 years old.

Jan 1, 1989

By Francis G. Stehli

Though sedimentary rocks comprise only about five percent of the volume of the continental crust, they cover about 80% of its surface, serve as important reservoirs for fluids, contain reserves of non-metallic minerals, and have in general been extensively drilled. However, most drilling has been shallow in comparison to the thickness of the crust and such deep drilling as has taken place is very strongly localized in sedimentary basins. This may be seen by reference to Figures 1 and 2 which show the location of wells that drilled deeper than 15,000' [=] 4.6 km. (Figure 1) and those that drilled below 20,000' [=] 6.15 km. (Figure 2). It is apparent that, even in regions of sedimentary cover, direct exploration below six kilometers has been very restricted. In the case of the metamorphic and igneous rocks which make up 95% of the volume of the crust, direct exploration has been much less extensive in terms of both area and depth. The present state of our knowledge of the crust below a' thin surface layer stands in marked contrast to our growing present need for raw materials and the needs of future generations. It also stands in contrast to our need for enhanced, scientific knowledge of the deeper crust, its configuration, its present state, its hydrothermal systems,-its evolution, and its materials. Lessons learned in exploring the third dimension of the sea floor, the vigorous prosecution of seismic profiling, the development of testable models for hydrothermal systems and mineral deposits, the need for better understanding of heat flow, state of stress, earthquake mechanisms, and a host of other phenomena all suggest that it is time to launch a national program for scientific exploration of the crust which uses drilling to test important hypotheses developed on the basis of indirect evidence.

Jan 1, 1985

By James J. Scott

To the safety engineer, mine planning engineer, and mine inspector associated with an underground operation, stability of the underground structure is of the utmost importance. In the United States in 1961 rock falls killed 167 miners, crippled many more, and cost the industry a fortune in lost equipment and production. Much research has been carried on to try to find ways to eliminate this loss of life and property. Within the past few years the interest in rock mechanics as a science has been at its highest point, Private industry, government agencies, universities and foundations have launched studies to gain a better basic understanding of the stability of underground openings.

Jan 1, 1966

By Robert J. Timko

New methods of reducing stopping leakage have been investigated by Mine Safety Appliance Research Corporation, working under contract to the U. S. Bureau of Mines. It was found that proper construction techniques are far more important in reducing leakage than the type of sealant used, provided the sealant has sufficient adhesion and strength. Leakage could also be substantially reduced by brushing on modified mortar sealants rather than using the accepted method of trowelling them on.

Jan 1, 1982

By J. P. Matoney

The operation of a modern coal preparation plant, particularly in western Canada, is a very complex task. Most western Canadian operations are processing two or more, sometimes up to ten, different seams through the same plant. This requires a sophisticated multi-circuit plant that needs close operational control. Add the soft nature and large amounts of natural fines of western Canadian coal and you have a formidable cleaning task. To assist in the operation, programmable controllers and sophisticated control concepts are being more widely used. Two of the newest coal preparation plants in Canada have been designed by Raymond Kaiser Engineers Inc. and its Canadian subsidiary, Phillips Barratt Kaiser Engineering, Ltd. The use of programmable controllers and control systems will be illustrated by showing their application in a "typical" western Canadian coal plant. This example will cover flowsheet design, control concept systems application, and possible future uses.

Jan 1, 1983

By R. L. Roller

In recent years, there have been many articles and papers written on the use of specially designed belt conveyor systems in mining operations, either economic studies or actual experience. These papers generally conclude that the use of these systems can reduce overall costs from 10% to 40% over conventional methods using general purpose equipment (truck/shovel, scrapers, etc.). However, they also generally conclude that conveyor systems are inflexible and capital intensive. With the increasing cost of mobile equipment, the capital cost conclusion is losing steam, particularly when the costs of maintenance shops, road and ramp construction and other related start-up costs are thrown in. Attention here will be focused on answers to flexibility related questions, but first, a look at costs in general. Basic production economics tell us that when we have a small job to do, it is cost effective to use simple, low cost, general purpose tools which will have a minimum impact on total cost. It also tells us that when we have a large project, we can employ methods using special, relatively expensive production tools. Figure 1 illustrates what occurs on projects, of different sizes, with various quantities of production. With small quantities of work, the cost per unit of work starts out much lower using general purpose equipment, rather than using special purpose methods and equipment. However, at a relatively low quantity of work, the cost hits a lower limit and, regardless of how great the quantity of work, the unit cost can never go any lower.

Jan 1, 1985

By B. J. Scheiner

The Federal Bureau of Mines has developed a chlorine-oxygen leaching technique for the recovery of metal values from lead-zinc sulfide concentrates. Lead, zinc, copper, cadmium, and silver extractions are in the 95- to 99.9-percent range. During leaching, the zinc, copper, cadmium, and silver are solubilized as metal chlorides, and lead is converted to insoluble lead sulfate. The iron contained in the concentrate is converted to insoluble iron oxide, and a majority of the sulfide is converted to elemental sulfur Minor metals such as copper, cadmium, and silver are recovered by precipitation with zinc dust. Zinc is then recovered from the purified zinc chloride solution by evaporation to dryness; the lead is recovered from the leach residue by brine leaching and crystallization to produce lead chloride. Recovery of zinc and lead metals by fused-salt electrolysis of the chlorides is being studied separately.

Jan 1, 1975

By Edwin H. Bentzen

Talc, as a mineral, is rather widespread, but as an ore sultable for mining, it is rather limited. Materials sold as "talc" range from the impeccable white material from Italy to a gray-green-bluish material from Virginia. Some uses of the material called "talc" seem to be determined by the color of the material, some by the chemistry of the material, and some by the particle size of the ground material. But, there seems to be some overlapping of criteria used to judge the acceptability of a raw material. So then, any producer of talc material that is not a consumer of this raw material is faced with the age-old problems: "what do I call the stuff, and to whom should I try to sell it?" The answer to the first part is easy: if you want a high price, call it "talc"; if you want a low price, call it "soapstone". This may seem like a very simplified answer, but it is apparent that some of the products sold as "talc" have more than a minor amount of impurities in them; whereas, if they were called "soapstone", these same products would probably get a lower price.

Jan 1, 1973

By Saul Escalara

Data on sulfonate adsorption by silicate minerals are very scarce in the literatures. Perhaps the only comprehensive paper written on the topic was done by Fuerstenau and Bhappu (1); this work dealt exclusively with quartz but included many important suggestions as to the form and nature of the hydroxy-sulfonate species of some cations formed during the conditioning step and their effect on the flotation response of quartz. Another paper by the same authors (2) contains additional data on the role of hydrolysis in sulfonate flotation of beryl. As postulated by Fuerstenau and Bhappu, a solid form of cationic sulfonate functions as the collecting species to produce flotation of quartz and beryl. According to the authors, the solid compound is a hydroxy-sulfonate of a given cation, where the hydrogen of the hydroxyl part provides a means for bonding of the species to the mineral surface; thus, the presence of hydroxyl in the neutral precipitated compound is of primary importance to produce flotation. Although the preceding examples illustrate the effect of a sulfonate collector in silicate systems other than plagioclases, they are important as examples of processes of hydroxy-sulfonate complex formation. Since the plagioclase minerals con¬tain Ca(II) and Al(III) cations, which are very reactive in sulfonate media (1), the formation of hydroxy-sulfonate compounds with these cations released from the solid phase may well prove to be the cause for their flotation.

Jan 1, 1973

By John N. Murphy

The past five years have seen communications techniques and hardware developed by the Bureau of Mines and its contractors increasingly brought into use in U.S. mines. The Bureau of Mines philosophy has been to help develop and introduce new hardware that goes as far as possible toward meeting the mining industry's needs. The Bureau of Nines programs are also designed to provide continuous fallout of new communications capabilities which are introduced to the mine operators as they occur. As more progress is made in meeting mine comnications needs, it is hoped that the mining industry will readily adopt the equipment and techniques that it finds most useful in meeting its individual needs. This paper reports on recent advances achieved in the development of improved nine communications systems.

Jan 1, 1976

By David S. Smith

Almost nine years after the assertion of enormous and pervasive federal control over coal mines by means of the Federal Coal Mine Safety and Health Act of 1969, 30 USC Section 801 et seq, as amended by the Federal Mine Safety and Health Act of 1977 (which basically increases the punitive powers of government) a brief assessment of some of the underlying causes, present status, and possible alternatives to governmental control is appropriate. In a governmental system based upon the principles of democracy and the protection of individual freedoms and constitutional rights the ultimate mechanism for abrogation of these rights is the creation and exploitation of fear. Machiavelli in rendering advice concerning the power over men provided by fear stated, "... it is much safer to be feared than loved .. fear preserves (the government) by a dread of punishment which never fails." The Prince. Within the context of the assumption of control by the government over industries or segments of our population - popular fear provides a convenient and almost necessary mechanism for the avoidance by law or regulation of democratic principles. The popular fear of coal mines has been successfully exploited by various goal oriented groups in the past and most recently by a Congressional constituency with a vested interest in controlling the mines through regulation.

Jan 1, 1979

By Y. Wang, G. Xu, N. A. Amoah, A. Kumar

Mining-induced coal dust causes various respiratory diseases to mine workers, such as coal workers’ pneumoconiosis (CWP). Current available underground monitors are expensive, heavy and only measure mass concentration. These disadvantages limit them for regulatory sample monitoring purposes only while personal exposure levels for most miners remain unknown, risking miners to potential overexposures. Low-cost light scattering PM sensors offer a potential solution to this problem with capability of high spatio-temporal resolution PM characterization. However, these sensors require careful calibration before they can be applied in mining environments. There is basically no comprehensive study in the literature using a standard protocol assessing these sensors for coal dust monitoring. With the aim of calibrating the PMS5003 sensors for coal dust monitoring, we design the calibration method and system to calibrate these low-cost PM sensors coal dust monitoring. Working principles of present coal dust monitor and low-cost sensors are presented in detail. The linear regression calibration model which is used for the sensor calibration is further described. Sensor calibration and evaluation protocols are comprehensively compared and discussed. This investigation reveals the feasibility of low-cost sensors for real-time personal coal dust monitoring in underground coal mines.

Mar 2, 2022

By Oluwafemi Salami

Conducting full-scale fire experiments in underground mines is difficult and expensive. Sometimes, it is impossible to carry out fire tests in mines due to the danger they pose to mine workers and the underground facilities. However, understanding the potential occurrence of fires in a mine and their dynamics is critical to developing an appropriate emergency evacuation plan, fire suppression, and firefighting techniques. In this study, a numerical fire model using computational fluid dynamics (CFD) with fire dynamics simulator (FDS) 6.7.6 was developed to examine the influence of tunnel bifurcation on maximum temperature beneath a tunnel ceiling. The model was validated using full-scale experimental data. The maximum ceiling gas temperature predicted using FDS and measured maximum smoke temperature during the experiment shows good agreement. The study shows that bifurcation could lower the maximum ceiling temperature of fire-induced smoke in a subsurface environment. The findings from this study apply to the broader field of ventilation and fire life safety in tunnels and other underground environments.

Jun 23, 2024

By J. R. Evans

In order to patent an industrial mineral placer mining claim, it must incorporate an economic deposit. Each ten acre parcel is evaluated for its mineral -in -character nature. Nonmineral -in -character parcels cannot be patented. Economic concerns include: claim locations, dummy locators, common variety nature, "excess reserves," and environmental constraints. Also, geologic and mineralogic studies, sampling and testing procedures are vital. Mining, milling, processing cost, and taxes must be evaluated. Product marketability analysis is necessary before starting any cash flow or discounted cash flow study. Valid data is essential to evaluate an economic industrial mineral deposit.

Jan 1, 1997

By G. Brien, O&apos

Selective in-plant breakage was investigated at a Central Queensland, Australia mine. Component seams and size fractions from in-plant samples were characterized petrographically and probability analysis of vitrinite reflectance data used to track the distribution of seam proportions through the plant. Results show that the 2 seams reported differentially to coarse and fine circuits, mainly as a function of coal type rather than rank. Seams were also preferentially concentrated in different size fractions of the coarse circuit. Breakage in the coarse coal centrifuge generated approximately 4% of -0.5 mm fines, but was not seam specific.

Jan 1, 1996

By Guy T. McBride

Mr. Chairman, Fellow Keynoters, Ladies, and Gentlemen: It is purposed to consider the theme of this meeting, "The 1970's - Pivotal Decade for the Mineral Industries," from the particular -- some would say peculiar -- point of view of one engaged in mineral engineering education, and this coign of vantage prompts the textbookish subtitle, "Problems and Solutions (?) in Undergraduate Mineral Engineering Education." Three interrelated problems, or problem areas, will be presented and discussed, and where solutions seem to be emerging or seem worthy to be suggested, they will be identified. The three problems are: 1. The goals, and therefore the course requirements, of the undergraduate curricula are in question, 2. The unit costs of undergraduate education appear excessive to those who bear the charges, and 3. The social ambience of the day affects for the worse the work attitudes and the career motivation of both prospective and in-course students. The Need. - Any discussion of these problems must bottom upon recognized national needs for minerals and a technologically sound minerals industry staffed by competent engineers, particularly at the exploration, development, and production levels, Fortunately, these needs have been recognized and to some extent quantified, and they are even now under further intensive study by some of the most competent members of our society and profession. The latter reference is, of course, to the current work of the National Commission on Materials Policy (U.S.A.) under the executive directorship of Dr. James Boyd. Predating this, and perhaps to some extent

Jan 1, 1972

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 G. T. Lineberry

There is a critical need for effective instructional materials at the university level and for an upgrading of mine safety and health in the mining engineering curriculum. A fundamental approach to mine safety and health is recast into the familiar 3 E's: engineering, education, and enforcement, in that order. Each is briefly reviewed and their interdependence emphasized. A unique philosophy for successfully integrating safety and health principles into the mining engineering curriculum is offered. The concept of textbook ?tailoring? is discussed and defended, permitting rapid assemblage and synthesis of existing educational materials. Final recommendations are made for a u, comprehensive approach to mine safety and health education in the undergraduate curriculum.

Jan 1, 1987