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By Shigeru Sarata

Working places in underground mines are formed by digging. The main feature of underground working places is that they are surrounded by rock. Digging through rock, which is main operation of mining, generates great reacting force. In many cases, supports are required to maintain a roof. Working places change their location with progress of mining operation. Therefore, for automate the work in such environment, a locomotive mechanism which can endure great reacting force, can support effectively the roof and floor, and has high moving performance in rough environment, might be required. In narrow underground environment which is surrounded by rock, it is possible to generate great fixing force by means of a jack which is set between the roof and floor or both side wall it is usual to apply a jack as anchor post for fixing machinery or reacting force. Self advancing supports widely used in long wall faces in coal mines could be said an example of locomotive mechanism with propping up fixing method. However it is difficult to say that ordinary self advancing supports have enough adaptability for various condition of the roof and floor. New locomotive method for underground working place 'Swing Phase Locomotion' is proposed. It is achieved by mechanism based on frame type support and synchronous control of jacks. Furthermore, to achieved high adaptability to various conditions of the roof and floor, another walking mechanism has been developed. The mechanism employs propping up jack as its legs.

Jan 1, 1989

By Robert W. Miller, Rhoda S. Kriesel

INTRODUCTION With each passing year, the general public becomes increasingly aware of the potential hazards associated with many products and services previously considered unharmful. This new consciousness is especially evident in the workplace, both as the result of advances in scientific understanding and the influx of concerned, responsible professionals into the labor movement. For example, data produced by epidemiologists doing retrospective mortality studies which related mortality to toxic substance exposures has often been the prime motivating factor behind reductions in exposure standards. This certainly has been the historical case with many radiation exposure standards, including the limitations set for "Working Level" exposure. The concept of "Working Level" was introduced in PHS Publication No. 494 as a result of both the difficulty in relating radiation units to biological effects and the complexity of interaction of radon daughters with the physical environment. WORKING LEVEL One working level is defined as any combination of radon daughters in one liter of air that will alternately release 1.7 x 105 MEV of alpha energy during decay of 210pb (RaD). Its usefulness is that working level can be readily measured in both the field and the laboratory. Because of this, existing occupational exposure standards for radon daughters in both the U. S. and other countries use working level as their basis. In the U. S., the last twenty years has witnessed a significant reduction in radiation exposure standards from 120 working level months to 4 working level months per year. New international standards are being proposed that would be only slightly higher than these current U. S. standards. POTENTIAL EXPOSURES TO RADON DAUGHTERS The universal use of nuclear power, along with the transfer of nuclear technology to developing nations, has significantly increased the demand for fuels. As a result, uranium mining operations have expanded and increased numbers of miners are regularly exposed to radon daughters. In addition to potential exposures in uranium mines, other deep mines such as tin, gold, platinum and tungsten, also have potential exposures due to the distribution of uranium and its accompanying radium throughout much of the earth's crust. The energy crisis has also prompted interest in general population exposure to radon daughters in buildings. Many homeowners, using additional insulation and caulking to seal cracks and conserve energy, have reduced indoor ventilation to the point where working level exposure could become significant, especially in homes with unventilated crawl spaces. In fact, several serious exposure situations have occurred where mine tailings were used for building materials. MEASUREMENT TECHNIQUES Historically, rapid and convenient measurement techniques have been actively sought to improve the ability of ventilation engineers to limit mining exposures through ventilation control. A number of measurement techniques have been developed, including the Kusnetz method (further elaborated by Shalaynev) and techniques developed by Rolle and Tsivoglou. All, however, suffer from similar handicaps that prevent their usefulness in the mining environment. Their main limitation, in terms of minimizing employee exposure, is the elapsed time from the start of sampling until the results can be calculated. It is usually 40 to 90 minutes. This time delay presents both serious economic limitations as well as the potential for exposing workers to high radon daughter concentrations until calculations are completed and corrections made. Further reducing the utility of the Kusnetz and Tsivoglou techniques is the need for tedious calculations that increase the possibility of human error along with the need for cumbersome sampling equipment that is not ideally suited to the mining environment. INSTANT WORKING LEVEL METER To alleviate these problems, the idea of an Instant Working Level Meter was conceived by several groups. Several such instruments were proposed, built, and tested with disappointing results. Although the concepts behind them were sound, the instruments simply failed to measure working level without excessive distortion. In addition, their cost was relatively high, gamma background presented a problem, and sophisticated computations were necessary to determine working level. In short, these systems lacked the design engineering that would make them suitable for the demands of a mining environment.

Jan 1, 1981

By A. S. Azman

The mining workforce experiences high rates of hazardous noise exposure and hearing loss. However, previous studies have identified specific behavioral and attitudinal barriers that keep miners from effectively acting to prevent their own hearing loss. NIOSH has developed several new hearing loss prevention tools and interventions that specifically target these barriers to prevention. The NIOSH Hearing Loss Simulator addresses motivation to take action and knowledge about the consequences of noise exposure. The QuickFit earplug test device and QuickFitWeb online hearing protection tester address barriers to effective earplug and earmuff use by verifying at least 15 decibels of protection. The NIOSH Roll-Pull-Hold technique helps miners obtain better protection through an easy-to-remember set of steps that improves attenuation by 9 decibels. The ?Inquiring Ears Want to Know? fact sheet helps miners to understand audiograms and to use them to maintain their hearing health. Each of these interventions can be used within the context of a comprehensive hearing loss prevention program.

Jan 1, 2010

By Pierre Longtin

"Replacing the aging roadway access to the iconic Golden Gate Bridge, thereby ensuring traffic safety and robustness in case of seismic occurrences, provided an opportunity for major design improvements as well as the development of a parkway that would include the construction of four new tunnels. With an eye to the future, the Doyle Drive replacement project aimed to meet the highest standards for environmental stewardship beyond regulatory requirements. Understanding that lighting equipment is the tunnel‘s subsystem that uses the most energy, the operator was looking for a sustainable solution to light the tunnels. An Intelligent Lighting Control System (ILCS), designed specifically for road tunnels, was acquired to individually control the almost 2000 luminaires lighting the four tunnels. This paper will show the results in terms of energy and operational savings generated over the nine months of operation between the commissioning and the conference in April 2016. INTRODUCTION Electrical & mechanical (E&M) equipment represents an average of 10 % of a tunnel total construction cost. Once the civil infrastructure completed, E&M equipment drives the main part of the expense during a tunnel useful life. Table 1 below describes the impact of various types of energy consumption and their cost impact in tunnels of less than 500 m. It is clear that lighting is the sub-system that requires the most energy. A good lighting strategy is the key to reducing energy consumption due to lighting and a viable solution that will bring important savings in tunnel operations.With a price of $0.14/kWh in California and a planned increase between 3% and 6% per year during the period 2013-2040, the tunnel operators could not afford to overlit the tunnels—particularly when they have to operate it for the next 30 years. However, they also need to maintain the right lighting level to ensure driver safety all the time. The Presidio Parkway project includes the Battery tunnels, which are 240 m (790 feet) and 230 m (750 feet) in length, and the Main Post tunnels, which are 280 m (920 feet) and 315 m (1030 feet) in length."

Jan 1, 2016

By H. Ziock, J. Ruby, A. A. Johnson

Power generation systems that promote energy security and environmental benefits are highly desired and pursued by a number of government and industry programs. Gasification of coal, other fossil fuels, or biomass has the technical promise of high efficiency and low or zero emission. Gasification for the purpose of electrical power generation has been researched, developed and demonstrated over the last 20 years, but for many reasons is not viewed as economically competitive. This paper describes a coal-based gasification technology well suited to mid and long-term goals of secure, environmentally clean energy. The technology should be adaptable for use with other carbon-based fuels including biomass and a full range of fossil fuels. The new zero emission gasification process is sponsored by ZECA Corporation, a continuation of the Zero Emission Coal Alliance (ZECA). ZECA has completed process design and engineering to assess the viability of a concept originated at Los Alamos National Laboratory, and the creation of a business plan to define paths for advancing the technology toward a near-term goal pilot plant. The zero emission carbon (ZEC) technology includes hydrogasification, the production of hydrogen and the carbonation of lime with CO2. For the power generation base case, the hydrogen is used in high temperature coal compatible fuel cells to produce electricity and the carbonate is calcined to produce a pure stream of CO2for sequestration. This paper provides the status of work with the ZEC technology and the availability of crucial equipment, materials and required testing. Discussions are presented for future actions to accelerate the technology assessment, testing and demonstration of a ZEC plant. Brief remarks are provided on complementary projects dealing withCO2separation and gasification costs.

Jan 1, 2004

By Arthur E. Lord, W. Martin McCabe, Robert M. Koerner

Following the driving of each new section of tunnel, a prompt decision is required regarding the type and extent of primary support to control convergence and prevent ground failure. Sometime thereafter, the effectiveness of the in-place support must be evaluated over the entire length of excavation. It is therefore extremely desirable to have available a lightweight, portable, easy to install and interpret, cost effective monitoring system to assist with these ground control functions. Such a system can be assembled based on the acoustic emission (or microseismic) technique. This monitoring technique uses a piezoelectric transducer to detect subaudible noises associated with deformation of and/or crack propagation in the soil or rock being monitored. After detection, the signals are then amplified, filtered and electronically counted to provide a quantified assessment of the stability of the structure. In the simplest sense, the absence of emission, or counts, signifies no deformation and thus stability. Conversely, the occurrance of counts signifies instability to varying degrees. The higher the count rate, the greater the instability and the need for immediate or additional support. Described in this paper is an overview of the acoustic emission (microseismic) method, details of its use in a laboratory study measuring convergence and stand-up time in soil, and the behavior of rock samples under similar stress conditions. Field use of the method is recommended for ground control monitoring in tunnels, and some suggestions regarding monitoring procedure are presented.

Jan 1, 1979

By F. C. Bond

Nature of Empirical Calculations The size reduction of large tonnages of ore and rock is an operation of great magnitude. It is a necessary and important part of industry. Its development has been motivated by practical need and has followed the path of an industrial art without much help from theoretical science. Knowledge has been accumulated from experience. Trial and error established the methods; then collected data were tabulated and served as the basis for empirical equations that have been continually modi¬fied and amplified as new data became available. These equations now constitute the bulk of our present knowledge of comminution. There is no accepted scientific theory that is basic to comminution. In electrical, mechanical, and civil engineering, as well as in many other industrial activities, such theories exist and are extremely help¬ful, but rock is essentially heterogeneous, and the zones of weakness that control its breakage are thoroughly diversified. No theory has yet been discovered which can account for the variability of rock, although many attempts have been made. Empirical equations tell nothing of the why of a phenomenon, but if they are properly derived they can tell much about the how. They always represent only an approximation of behavior but never a law. In a proper empirical equation a symbol is assigned for each of the variable quantities that obviously affect the relationship. In a grinding mill these include mill diameter, mill speed, and feed rate among them. In setting up and revising an empirical equation the cardinal princi¬ple in establishing and modifying it is this: any change must be strictly ascribed to the variable which caused it. A useful empirical equation is rendered useless when a change in any convenient coefficient or exponent is made to make it fit a particular set of data, without certainty that the altered coefficient or exponent is the responsible variable in the new data. Such indiscriminate revisions have brought the use of empirical equations into some disrepute. When existing equations are changed to accommodate new data it is a good rule to make a change which gives results intermediate between the new and the old. A halfway point is usually a good choice.

Jan 1, 1985

By Ronald S. Conti, Harry Dobroski

Re1iabl e monitoring a1ong an underground mine belt line is of great concern because of combustibles, electrical apparatus, and friction. Belt entries are strategically located where a fire can have rapid and disastrous consequences. This paper reviews conventional distributed temperature sensing systems based on resistive, thermistor, and thermocouple effects. These are shown to provide limited benefits. A new system tested by the U.S. Bureau of Mines based on fiber optics and time domain reflectrometry, promises much better temperature and spatial resolution, faster response, inexpensive cable, longer distance, and comprehensive data analysis. Test results in a small, controlled, in-mine fire are given.

Jan 1, 1992

By J. Raatikainen, I. Auranen

"INTRODUCTION Sorting technology has advanced rapidly recently. Of the two possibilities particle sorting has advanced especially in introducing new sensors and the use of multiple sensors. The analyzing and computing lead times have also shortened. This has made it a viable technology option for many applications but not for the most important sorting task at a mine; the run-of mine ore. Bulk sorting, however, has advanced in smaller steps, even if the technology has the capability to tackle the run-of-mine ore and offers a high potential to bring mines substantial economic benefits. The sensors, which are useful are restricted by the difficult operating conditions or by the ore characteristics. One of the important features of run-of-mine sorting technology is the major material handling infrastructure required. The capital expenditure can be substantial requiring good understanding of the sortability curve (grade-recovery curve) behavior of the ore. This paper discusses one industrial case, where substantial amount of data measured from the ore feed belt has been obtained. This data was then analyzed for the grade recovery curves obtainable from that ore with sorting. EXPERIMENTAL The XRF measurement used was the FCA device from IMA Engineering (Fig.1). It is a specially built version of XRF designed to operate with coarse material. The measurement was situated at the main belt conveyor taking ore from the primary crusher to the stockpile. The crushed ore was about 80% -300 mm at a capacity of 1100-1200 tph (Fig.2). Measurement times were varied from 30 seconds to a minute. Measurements were obtained over several months.As the XRF is a surface distribution measuring technique, the measurement was first tested upon accuracy and reproducibility against plant daily wet chemical assays and against on-line Courier feed analysis. As there is a varying delay in the ore stockpile, the delay time was used as a variant in the validation. Different measurement times were tested for accuracy. A one minute measurement time gave a total measurement relative standard error, which was both for Cu and Ni below 3%. The results showed also very robust correlations; for Cu, the correlation coefficient was R > 0,94 for one minute measurements over three months and R > 0,86 for Ni respectively. Fig 3. Shows a measurement period of two hours showing substantial feed grade variations (given as relative value; 1.0 represents the mean value during the measurement month)."

Jan 1, 2018

By Rick L. Williamson

International lending institutions have charters requiring projects that are seeking loans to adhere to certain environmental performance standards, including compliance with host-country environmental laws, as well as observance of international environmental policies and guidelines. The most commonly applied international environmental policies and guidelines are those established by The World Bank. Lenders require a review by an independent engineer to determine that the feasibility study plans have been developed in accordance with the applicable environmental commitments. Lender agreements require independent engineer evaluation of environmental performance through the construction phase and initial operations phase of the project, culminating in the issuance of an "Environ- mental Completion Certificate."

Jan 1, 2001

By Robert A. Jankowski, J. Drew Potts

By implementing various mining practices, mine operators can reduce the respirable dust exposure levels of the roof bolter and the continuous miner operators. The Bureau of Mines has developed a computer program, entitled AMP (Alternative Mining Practices), that gives a quantitative comparison of these reductions. The alternative mining practices and their corresponding reductions in dust exposure levels that are evaluated by the program include a remote control continuous miner, a half-curtain ventilation system, two auxiliary fan-tubing bypass ventilation systems, a modified cutting sequence, a comparison between single-split and double-split ventilation networks, and a comparison between exhausting brattice and exhausting tubing. Descriptions of each of these mining practices are included in the report. The report also includes a hypothetical case study to show how AMP enables mine operators to select the technique(s) that is best suited to their particular needs. AMP is a compiled basic program that has been designed to run on computers with a DOS version 2.0 or later operating system. It includes high resolution graphics (640 X 200 dot positions) designed to run with video boards that are functionally compatible with the IBM Monochrome/ Printer Adapter. Graphic screens are selected from menus, and can be bypassed if the computer is not equipped to handle high resolution mode. Their primary function is to show proper implementation of the mining practices evaluated by the program. This package requires a minimum of 256K bytes of RAM. (Reference to specific products does not imply endorsement by the Bureau of Mines.)

Jan 1, 1987

By Wallace W. Wilson

It scarcely 1s possible to read a new issue of any of the principal mining trade journals without noting some mention of a major new overseas mining venture with which one or more domestic companies are involved. These projects seem to follow a fairly consistant pattern; most are large open pit mines, with relatively low grade ore bodies but huge reserves; the total price tag will be in nine significant figures and around half or more of the total cost will be for infrastructure. West1 noted that nearly $7 billion is being invested annually for new mining projects and the expansion of existing mining ventures, in the free world. He anticipates that by the year 1975 such investments would reach the $10-11 billion annual figure, and that in the five year period 1972-76 total capital requirements can be expected to aggregate around $45 billion. The proportion of this total investment which will be financed in some manner is difficult to estimate because of the variety of available financing arrangements. West estimated that around 75% of the total capital would come from internally generated funds, with the balance from external sources. Conceivably a substantially higher percentage could be attributable to external financing, especially it the trend of recent mineral development in Canada and Australia is any criterion, and of course, including local sales of equity as a part of the package.

Jan 1, 1973

By Martin P. Corriveau

It is not news to anyone in the mining industry that federal action in the prevention and abatement of air pollution has seriously affected the industry both directly and indirectly. It is the purpose of this paper to review how the development of federal action is directly affecting the coal mining industry's number one customer, the fossil-fuel-fired steam generating power plants and, consequently, the industry itself indirectly. In essence, Public Law 84-159 of 1955 as amended by the Clean Air Act of 1963 and its revisions in 1967 and 1970 progressively tightened federal coordination and management of air pollution control programs throughout these United States. The Environ- mental Protection Agency (E.P.A.) set up to direct the programs was charged to establish National Air Quality Standards, Standards of Performance for New Stationary Sources, and National Emission Standards for Hazardous Air Pollutants.

Jan 1, 1973

By J. Kallioinen

Flotation of low grade Ni ores with serpentinite host rock tend to yield low recoveries of Ni With high MgO contents in the concentrate. The recovery can be enhanced by optimizing the sub-processes in the pulp and in the froth. The new OF-100 flotation cell has been designed to be adaptable to different feed fineness (Coarse, Fine). The losses can according the research conducted at Outokumpu's Hitura plant be substantially decreased by OF-100's new rotor and stator design and froth zone geometry. The froth residence time is used to adapt for feed particle size changes measured by the Outokumpu PSI- 200. Models for the behaviour of different particle Sizes in the sub-processes have been developed. The modified froth zone geometry and the capability of maintaining a froth of desired thickness allows efficient washing of the obtained concentrate producing low levels of MgO.

Jan 1, 1994

By David M. Spatz

Ore deposit models are defined largely by physical geologic features that relate conveniently to remote sensing. New Landsat, SPOT, RADARSAT and other multispectral and hyperspectral sensors with improved spatial resolution are currently in development. Near-infrared and thermal airborne hyperspectral scanners hold outstanding promise for both mineral exploration and feasibility stage mapping at potential new mining projects. These scanners are capable of identifying silicification, differentiating silicate alteration types, and mapping compositional variations within igneous and metamorphic complexes. Research in 'mineral and rock spectrometry is helping to advance applications of remote sensing. Hyperspectral scanners are capable of differentiating compositional variations within individual mineral species. Innovative data processing techniques continue to enhance computer software applications and facilitate imagery analysis by the geologist. Today, . remote sensing imagery is commonly integrated with multiple data sets in GIS format to form the core data base for regional exploration programs.

Jan 1, 1995

By D. R. Schricker

Mine managers rely on their experience, section foreman's daily reports and occasional time studies to make important production, maintenance and forecasting decisions. This information is often subjective and imprecise, consumes expensive engineers time, is often biased and is restricted to short time periods. Managers need better information. Furthermore, if a recently purchased machine is being evaluated, a large increase (>10%) in productivity may be obvious, but small increases are usually masked by other variables. In today's highly competitive markets, cumulative small changes are important, especially since managers have already exhausted most available, obvious avenues of improvement. A technique to separate these charges from effects of other variables and to quantify the target effect is necessary. CSM researchers are addressing this need by developing an intelligent decision support system (IDSS). It provides key production and maintenance information to support management decisions by recognizing patterns in mining machine sensor data and representing knowledge about mine management, operations, layout and equipment. A continuous miner section at Western Fuels-Utah Inc.'s Deserado Mine in Rangely, CO is the test facility for the research. Power transducers located in the sections load center provide kilowatt versus time data from continuous section equipment. The IDSS pattern recognition algorithms classify the kilowatt versus time patterns into individual machine operating modes. It produces an output similar to a typical industrial engineering time study but continuously, automatically and without an engineer in the section. It is relatively easy for a time-study engineer to identify the stop and end points of a cycle element and classify it by looking at the machine and glancing at a stop watch. The problem is that monitoring system hardware and software do not have these unique capabilities. Consequently, IDSS algorithms must automatically define the begin and end points of machine tasks and identify the task by recognizing patterns in kilowatt versus time data. However, many mines have file drawers of time-study type data that are not very useful. So, IDSS contains the knowledge representation subsystem (IDSS/KRS) to produce short reports containing only key information. This is difficult because mine environments continually change and information requirements differ for each management level. Consequently, IDSS/KRS must learn and adapt to new conditions in a dynamic mining environment.

Jan 1, 1990

By John B. Draper

The 1980 Mine Dewatering Act was enacted to protect water rights and to allow mine dewatering to proceed where impairment of a water right might have otherwise created a bar to mine development. In New Mexico, new appropriations for beneficial use are subject to the State Engineer's jurisdiction and are granted only upon a showing of non-impairment. Before 1980, mine dewatering was not considered a beneficial use, nor was it considered waste. The Act brings mine dewatering under the jurisdiction of the State Engineer, makes it subject to the same requirements as an application for appropriation for beneficial use, grants the right to replace the water of users whose rights would be impaired by mine dewatering without a plan of replacement, and extends the right of replacement to non-mining appropriations of water for beneficial use, Application of the Act requires determination of the definition of impairment (the threshold of significant impact on existing water rights), hydrologic evaluations to determine the impact of the proposed dewatering, and preparation and execution of a plan of replacement to avoid impairment of existing rights.

Jan 1, 1983

By G. D. Trump, F. L. Stanley

Spirals have become one of the most popular methods for treating fine coal. Unfortunately, spirals tend to produce an undesirably high specific gravity cut point and often misplace significant amounts of coal and/or rock. In the present study, a process-engineering tool known as linear circuit analysis was used to identify problems with traditional spiral circuits and to suggest alternative configurations. These analyses indicate that a modified rougher-cleaner circuit incorporating a middlings recycle stream offers the best option for improving performance while maintaining a reasonable circulating load. In light of this finding, a full-scale test circuit was installed and evaluated at an existing preparation plant. Data obtained from the plant tests indicate that the new spiral circuit can simultaneously reduce the cut point and improve separation efficiency. Preliminary economic analysis show that the new circuit provides an attractive payback on capital investment.

Jan 1, 1999

By N. S. Tanious

The accuracy of vibrating wire stress meters has been questioned by various users in the mining industry. During an in situ coal pillar study, a laboratory evaluation program was developed to determine whether stress meters could produce reliable measurements in coal. More than $0 stress meters were tested for accuracy, repeatability, effects of setting pressure, and the concept of using a single curve for interpreting the stress-meter data. The testing medium was lucite, a material with a modulus of elasticity very similar to coal. The evaluation demonstrated that the stress meters did provide repeatable measurements, but that accuracy was lacking when the recommended interpretation technique was used. Therefore, a new technique was developed that required all stress meters to be calibrated in the laboratory before use in the field. This new technique reduced the average error to typically less than 10% and, in the worst case, to below 15%.

Jan 1, 1988

By J. Cooper, M. W. Staub

Environmental management systems (EMSs) have been in use for more than a decade. US mining companies are only just beginning to adopt EMSs. This lag is primarily due to lack of market forces and lack of evidence that EMSs add value over standard compliance programs. Several recent studies concluded EMSs improve environmental performance and reduce costs. State and federal regulatory agencies are using EMSs as an innovative tool to streamline the regulatory process and achieve continual environmental improvements. The climate is right for the mining industry to adopt an EMS model that improves environmental performance and takes advantage of new regulatory programs.

Jan 1, 2004