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By James J. Olson

This report summarizes the results of a review of foreign coal mining literature conducted under the Bureau's Advancing Coal Mining Technology program. In addition to a discussion on the historical development of mechanized longwall systems, and the current state-of-the-art method in Europe, this report summarizes the previous and ongoing Bureau efforts to adapt longwall technology to U.S. conditions. The bibliographic section of this report, divided into major categories such as mine design, face management, roadway development, strata control, powered roof supports, coal winning, conveying, and automation, contains over a thousand individual entries. The purpose of this report is to provide U.S. mining engineers with background information on longwall methodology and equipment developed in foreign countries (principally Europe). The Bureau of Mines, as part of its Advancing Coal Mining Technology program, is funding R&D projects to demonstrate that the longwall mining method, successfully used in the deep mines of Europe, can boost productivity and improve safety in certain U.S. mines.

Jan 1, 1977

By H. R. Pierce

A gas well has a certain definite capacity to deliver gas from the gas sand through the producing string of pipe. This capacity depends upon the pressures in the sand; that is, a well will deliver gas at a rate of flow which is determined by the formation or "shut-inn pressure in the sand and the back pressure at the face of the sand in the well. The three factors, rate of flow, formation or "shut-in" pressure, and the back pressure, for a given well, can be written into a fundamental relation which is strictly applicable only to that well. This relation can be used to determine the capacity of the well to deliver gas from any formation pressure against any back pressure held at the f ace of the sand in the well. Studies have been made of the deliveries of 400 gas wells operating under different conditions of pressure, Most of the wells which have been studied are in Osage County, Okla.; however, several representative studies have been made on wells in southern Louisiana, southern Texas, the Texas Panhandle, and West Virginia.

Jan 1, 1929

By D. E. Welcome, T. W. McDowell, R. G. Dong, S. F. Wiker

Workers using vibrating hand tools have the potential for developing health problems associated with repeated forceful actions and exposures to hand-transmitted vibration. Hand-arm vibration syndrome (HAVS) and other hand-arm system disorders have been associated with such exposures.1-2 To better assess health risks, comprehensive evaluations of these exposures must include quantitative assessments of hand-tool coupling forces; unfortunately, no standardized method for quantifying hand forces exists. Handle instrumentation may be ill-suited for some field environments. Psychophysical force-recall techniques may provide alternatives to handle instrumentation. A thorough understanding of the effects of vibration and other factors on force-recall accuracy and reliability is important before such methods are applied in risk assessments. Methods In this study, the effects of vibration and other factors on the accuracy of psychophysical force-recall were explored in two experiments. Twelve male subjects participated in the first experiment. The second experiment employed 20 participants (10 female, 10 male). In each experiment, participants applied specific grip and push forces to an instrumented handle mounted on a shaker system. Participants were exposed to sinusoidal vibration at frequencies that ranged from 0 Hz to 250 Hz. Three levels of applied force (low: grip = 15 N/push = 25 N, medium: grip = 30 N/push = 50 N, and high: grip = 45 N/push = 75 N ) and two levels of vibration magnitude (low: ANSI 4-8-hr limit and high: ANSI <0.5-hr limit)3 were examined. During the vibration exposure period, participants were provided with visual feedback while they attempted to “memorize” the applied grip and push forces. At the conclusion of the vibration exposure/force memorization period and a controlled rest period, the participants tried to duplicate the grip and push forces on a non-vibrating handle without the aid of visual feedback. The effects of different vibration frequencies, vibration magnitudes, and grip and push force levels were tested in a random order from trial to trial. Results Participants tended to overestimate grip and push forces. Depending on exposure conditions, error means ranged from 2 N to 10 N. The ANOVA revealed that force-recall errors for exposures between 31.5 Hz and 63 Hz were significantly higher than those at other vibration frequencies (p < 0.05). The frequency effect is depicted in Figure 1. Error means were greater when participants were exposed to the higher vibration magnitude (mean = 9.1 N, 95% CI = 8.2-10.1 N) when compared with the lower vibration magnitude (mean = 4.9 N, 95% CI = 3.9-5.8 N) (p < 0.05). The effect of vibration magnitude is shown in Figure 2. The average error for

Jan 6, 2006

By N. Kumar Kittusamy

The purpose of this study was to assess the adequacy of the cab design and to determine the percentage of musculoskeletal symptoms among workers. A questionnaire was designed to assess demographics, work information, job history, and musculoskeletal symptoms in operators of heavy construction equipment. Information concerning equipment included design of the seat/chair, levers, pedals, bothersome vibration, quality of egress from the equipment, proper preventative maintenance and repairs, and age of the equipment. The body regions that were evaluated included the neck, middle/upper back, low-back, shoulder/upper-arm, elbow/forearm, wrist/hand, hip, knee, and ankle/foot. One hundred and eighty nine operators completed the questionnaire. The results indicate that these workers are at risk for developing musculoskeletal disorders, the need to perform a larger survey to further substantiate the outcome, and the need to quantify risk factors (i.e., whole-body vibration and static sitting postures).

Jan 1, 2003

By Frank K. McIntosh

Bauxite was first discovered in Tennessee, at Chattanooga, in 1906, during the construction of&apos; the McCallie Street tunnel through Missionary Ridge. Several years later, bauxite was found in sinking a well on the Perry or Isabella Stewart property. These and other deposits furnished a substantial tonnage for the abrasive and chemical industries during the years 1906 to, 1920. The search for domestic sources of war material prompted by World War II brought the Tennessee bauxite deposits to the attention of the Bureau of Mines. During the summer of 1942, James S. Cullison and E. Godwin, geologists of the United states Geological Survey, made a survey of the bauxite deposits of the area. In August 1942, Harold B. Ewoldt, a Bureau of Mines engineer, accompanied by the Geological Survey party visited the area and a drilling program was prepared. Drilling was started in November 1942 and continued until March 1943. A total of 2,519.5 feet in 38 holes was drilled on three properties.

Jan 1, 1949

By Ronald B. Hollenbeck

The value of mineral production in Alabama continued to increase and reached a new high of $260 million, 3 percent above the previous high established in 1967. Record high values were reported for bentonite, crushed marble, lime, miscellaneous clay, portland cement, salt, sand and gravel, and scrap mica. The value of coal, total cement, petroleum, and stone accounted for 87 percent of the State&apos;s total value of mineral production. Alabama ranked second among the States in the production of bauxite and scrap mica and third in kaolin, masonry cement, and native asphalt.

Jan 1, 1970

By George W. Huseman, W. D. Mcmillan

"INTRODUCTION Feldspars represent one of the most abundant groups of minerals and constitute nearly Go percent of the material contained in the igneous rocks. They are grouped in a series of related aluminum silicates with varying amounts of potash, soda, and lime. .Approximately 85 percent of the feldspar produced in the United States is used as a flux in the production of glass, pottery, enamel and sanitary ware, brick, and tile. Notwithstanding the abundance of feldspar in the earth's crust, the only deposits that are worked to any extent are the pegmatites or coarsely crystalline dikes where natural segregation of the constituents facilitates recovery of the feldspar with a minimum of free quartz, mica, tourmaline, garnet, and other iron-bearing minerals that are detrimental in most ceramic industries.Although there are three glassplants and numerous other ceramic industries in Texas, all of the feldspar used in these plants is from other States. In the Llano region of central Texas, however, there are numerous coarse pegmatite dikes consisting primarily of feldspar and quartz in ratios up to 3 to 1. One of the more important of these dikes is the Badu Hill deposit in Llano County, Tex., which was first described by Carl Chelf 4/ in 1942. Following an examination of the deposit by W. D. McMillan, engineer in charge of the Texas field office of the Bureau of Mines, in January 1946, a proposal was made to investigate the deposit by core drilling in cooperation with the Department of Ceramic Engineering, University of Texas. This report presents the results of the cooperative investigation, which was begun April 24, 1946, and completed May 17, 1946."

Jul 1, 1947

Develop a mobile manipulator that one person can use to lift and maneuver 50- to 600-pound loads. It can be used in maintenance shops and mines to reduce lifting accidents (Figure 1 and 2). Background Lifting heavy items is one of the leading causes of injury in the workplace. Mine Safety and Health Administration statistics showed that, in 2004, back injuries accounted for over 20% of all injuries (1,699 cases) and resulted in 110,000 lost days of work. Forty-one percent of those injuries resulted from materials-handling or maintenance activities.1 In addition to back injuries, lifting injuries include hernias, ruptures, sprains, and strains resulting from losing control of the item being lifted. Factors associated with accidents are weight of the item being lifted, awkward postures, inadequate handholds, and the working environment itself. High accident rates were noted when lifting items that ranged from 50 to 600 pounds, particularly in tight working quarters where maneuverability was critical. Research indicated that a mobile lifting arm would eliminate many lifting accidents in environments where other lifting devices (fork lifts, overhead cranes, mobile A-frames) would not be practical. NIOSH has built a first-generation mobile manipulator unit designed to be used on hard, level floors such as in a shop. The complexity of motion, number of moving parts, compact design, and design constraints of the manipulator required advanced computer-aided design work (Figure 3). As a result of the design work, thirty-eight claims are included in the patent applications. NIOSH will be conducting field trails and working with manufacturers to put the manipulator into industrial use.

Dec 1, 2006

By David C. Grant

A laboratory technique for simulating in-situ uranium mining was developed and used to determine the effects of leaching variables on permeability, uranium recovery, leach solution interaction with the ore-aquifer environment, and post-leach chemical leakage. In particular, ammonium bicarbonate, the commonly-used leach solution, was examined in great detail. Agitation leach tests were conducted to examine the effect on ammonium sorption and desorption of clay content, solution and clay ammonium levels, pH, and the type and concentration of other anions and cations in solution. Initial column tests were performed to determine the degree of ore-aquifer interaction that could be expected for various leach solutions; sulfuric acid, and ammonium, sodium, and potassium bi-carbonates. Subsequent tests examined various methods to restore the ores by lowering the post-leach chemical leakage. The restoration tests examined the use of reducing agents (e.g., ammonium bisulfite, sodium bisulfite; and sodium sulfite), ore blocking and stabilizing agents (e.g., sodium silicate, aluminum chloride, and magnesium-calcium salt).and ammonium displacement agents (e.g., aluminum chloride and lanthanum chloride-sulfate)

Jan 1, 1980

By Fred N. Kissell

In This Chapter [Instruments available to measure methane in mines and tunnels Using a portable detector in both accessible and restricted spaces Machine-mounted monitors: placement and response time Calibration of catalytic detectors for different gases and Misinterpreting warning signs This chapter gives guidelines for methane measurement in mines and tunnels. The emphasis is on the measurement procedure and the interpretation of the measurement rather than on the instrument itself.] The failure to properly sample for methane is a major contributing factor to methane explosion risk. Sampling errors are most likely to occur at mines or tunnels where the presence of methane is not suspected or during nonroutine tasks at mines or tunnels known to have gas. More specific information on methane sampling at continuous miner sections is in Chapter 3. Chapters 4 and 5 discuss sampling at longwall sections, and Chapter 14 discusses sampling at tunnels. METHANE DETECTORS FOR MINING Many models of gas detectors are available to measure methane concentrations, as well as most of the other contaminant gases found in mines and tunnels. An example is the iTX Multi-Gas Monitor, a portable gas detector available from Industrial Scientific Corp., Oakdale, PA. This handheld instrument measures several gases simultaneously. The cost (2004) ranges from $1,300 to $2,200, depending on the number of gases measured. Similar instruments are available from other manufacturers. Most methane detectors used in mining use a catalytic heat of combustion sensor to detect methane and other combustible gases. These have been proven through many years of reliable operation. For detection of methane, proper operation of catalytic heat of combustion sensors

Jan 6, 2006

To provide an engineering solution to wood crib design and deployment strategies that will ensure safety for underground coal mine workers. This is accomplished by preserving necessary ground control requirements while minimizing support costs or by developing new support strategies to enhance ground support in difficult conditions. A secondary objective is to be able to quantify wood crib support performance to define support requirements for alternative support systems. These objectives have been achieved through a simple-to-use computer program called the wood crib performance model (wcpm).

Jan 1, 1997

By George A. Morgan

The 53 countries that constituted Africa in 1989 accounted for a significant portion of total world output of a number of mineral commodities. Among the most significant minerals to be produced in Africa were andalusite, antimony, asbestos, bauxite, chromite, coal, cobalt, copper, diamond, fluorspar, gold, lithium minerals, manganese, phosphate, platinum-group metals, and the titanium minerals-ilmenite and rutile, vanadium, vermiculite, and zircon. Despite the underdevelopment of much of Africa, mineral raw materials played a very important part of the national economies of many of its countries. In terms of percent-age of export earnings, minerals accounted for more than 90% in some cases. In several countries with agrarian economies and little economic diversification such as Angola and Guinea, a single mining operation could represent an important source of foreign exchange. These latter operations tended to be the more easily mined surface deposits of diamond, gem stones, and precious metals. Mineral commodities for which Africa had a high percentage of world output were bauxite, 16%; chromite, 44.5%; cobalt, 76.5%; copper, 13.9%; diamond, 50.7%; gold, 32.9%; manganese, 27.1 %; phosphate, 22.1 %; platinum-group metals, 48%; uranium, 29.2%; vanadium, 54%; and vermiculite, 41 %. Several of these, chromite, cobalt, diamond, and manganese, were not produced in the United States.

Jan 1, 1992

By Ernest A. Curth

A 3-month study in 1971 of the Essen Roof Support and Rock Mechanics Research Center&apos;s program of roof and support evaluation included 25 mine trips. German miners must adopt mining methods and environmental control measures involving methane drainage and water infusion to improve productivity under severe natural conditions. Pressing problems in ground control must be solved such as cavities in front and above the supports at longwall faces and excessive convergence in gate roads. The Center developed automatic data processing methods to quantify the results of roof and support surveys and to establish criteria. Another approach to ground control is the study of mine models. The Center&apos;s laboratory has the facilities to test elements of powered roof support and whole assembled units. Face automation and roof control by powered shields are novel developments that are under close scrutiny in the field as well as in the laboratory. Though the Essen Center&apos;s roof and support evaluation techniques are tailored to the needs of the coal mining industry of the Federal Republic of Germany under conditions vastly different from those in the United States, some application may be found here, for instance, monitoring faces and roadways and preventive maintenance of hydraulic systems.

Jan 1, 1974

By Oliver Bowles

"Underground operation.In its broader sense the term ""mining"" is applied to all processes whereby raw materials are taken from the earth to be used as sources of mineral products. In a more restricted sense ""mining"" is applied to underground operations as contrasted with open pit work designated as quarrying. The tern is used in the restricted tense in this paper; for it relates to the exploitation of limestone deposits by modern methods of underground operation rather than by open pit methods.Present tendency toward miningIt may seem to some readers that a paper on mining limestone will find little general interest among lime plant operators, for only a limited number of them have yet resorted to this means of procuring raw materials. It is noteworthy, however, that a growing tendency exists toward underground operation, for one by one quarry owners are faced with increasing difficulties in open pit operation. It seems desirable, therefore, for operators to keep closely in touch with this gradual change in process, to inquire into the underlying causes, to compare costs, and to study the effects of the change in method on subsequent steps in calcining the stone to produce lime."

Mar 1, 1924

By K. P. Wang

The foundation of Japan&apos;s growing industrial and economic strength lies primarily in minerals, power, and technical know-how. Domestic raw material resources cannot supply domestic demand, and imports are indispensable. The Japanese are forced to acquire minerals and metals on a global basis, and their activities already have made an impact on international markets. A by-product of these efforts is the development and expansion of mines in many parts of the world to supply Japanese requirements. Japan now has a surplus capacity to produce finished products for consumption and export. Tradition-ally, domestic deficits in minerals have been met by importing crude materials. Because of the rising demand, however, the time has come when semi finished products as well as crude minerals are required. While the domestic market is the mainstay for Japan&apos;s industrial products, expanding export markets are essential for balancing trade and for providing economic prosperity and higher living standards for the Japanese people. Japan has a long history of mineral and industrial development, and the best in modern practices abroad has been adopted and modified for use under Japanese conditions of smaller enterprises, cheaper labor, and a more closely knit society. Generations of industrious workmen, technicians, and business-men have been trained in industrial occupations. Devastation of war temporarily slowed progress, but at the same time provided the opportunity for reconstruction, modernization, rationalization, and expansion. The Japanese excel in small and medium-sized operations, but they also have mastered large-scale production. Management is aggressive, practical, and strongly imbued with the concepts of effective utilization of resources. Integrated operations, diversification of facilities, intense competition among concerns in the domestic market, and close cooperation in foreign activities characterize Japanese industrial policies. Available capital has been utilized up to the limit for the establishment of mineral and other industrial facilities at home and abroad. Technology, machinery and equipment, and transport services have been exported along with venture capital, and funds have been advanced against future delivery of foreign raw materials. The Government has been restrained in regulatory functions and has provided technical services to private industry. Thus, Japan&apos;s technological foundations are secure, management practices are efficient, and government has stimulated production. The future outlook is bright for the continued rapid growth of mineral and other industries in Japan. Already supreme in Asia in per capita output and living standards, Japan steadily is gaining on the European countries. Steel production has overtaken the United Kingdom and is pressing the level in West Germany. Consumption of fuels and power is expanding at a rapid rate. Construction activities are booming. Japan has built up medium-sized non-ferrous industries. Its ability to produce the exotic metals needed in the nuclear space age is well established. Since Japan makes a great variety of mineral products, her overall posture in mineral extraction and processing is strong. Primarily as a result of intensive efforts in the mineral and other industrial fields, Japan is emerging in world markets as a serious competitor to all industrialized nations.

Jan 1, 1962

Overexposure to noise is a widespread, serious health hazard in the mining industry, and causes hearing losses to a large percentage of the mining population. Recognizing this fact, the Bureau has a major on-going research effort to address this problem area. These proceedings include an overview of the Bureau noise control program and summarize nine selected noise control research programs.

Jan 1, 1984

By Kathleen M. Kowalski-Trako?er

National Institute for Occupational Safety and Health re­searchers conducted a study to investigate the human response issues related to wearing a self-contained self-rescuer (SCSR). The goal was to develop training to educate miners on what they could expect from their units during an escape. Subjects included miners who had experience wearing SCSRs, manu­facturers, and researchers. Results identified nine key areas of concern: (1) starting the unit, (2) unit heat, (3) induction of coughing, (4) unit taste, (5) difficulty in breathing while wearing the unit, (6) quality of the air supplied, (7) nose clips, (8) goggles, and (9) the behavior of the breathing bag. In addition, researchers reviewed the literature on human response under duress. This article describes the expectations training program, which comprises the findings of the SCSR study and what is known about the normal human response in an emergency. The authors present background on SCSRs and the SCSR switchover procedure mandated in the recent federal Mine Improvement and New Emergency Response Act of 2006, which provided the impetus for the expectations training. Keywords disaster, escape, mining, self-contained self-rescuer, training

Jan 1, 2008

By Doss H. White

In 1989, Alabama&apos;s nonfuel mineral industry produced a State record of $463 million of nonfuel mineral commodities, an increase of $4 million over that reported by the State&apos;s mineral producers in 1988. The new record marked the fourth consecutive year in which mineral production increased over that of the previous year. Alabama ranked 22d among the States in total mineral value. Cement, stone, and sand and gravel were the three leading mineral commodities produced, accounting for 77% of Alabama&apos;s total mineral value. During the year, there were several acquisitions by Alabama cement and stone companies, and the only tantalum mine in the United States completed its first full year of operation.

Jan 1, 1991

By W. R. Crane

Recent papers on support of roof and top rock in mines representing present practice in so far as it hits been described by engineers in all of the principal mining countries, cover a relatively aide range of topics. The papers abstracted herein include such subjects as the testing of materials of support, failure and movement of rock above workings, effect of excessive pressures on rock masses, axed the application in mines of timber, metal, concrete, packing, and filling support. It is not within the scope of this paper to present a logical and orderly discussion of the elements of support and their application to conditions influenced by the material worked or the method of mining. Only the essential facts of a paper appear in the abstracts, the idea being to give a fairly clear picture of the behavior of various types of support under brows conditions and to put into concise form important information concerning present practice, modifications of practice, and the trend toward new practice. With such valuable facts from others experience made readily available, it Is hoped that the engineer with particular and often trying problems may obtain suggestions that will be immediately helpful.

Jan 1, 1932

By R. S. Dean

"INTRODUCTION The idea of direct steel is by no means new. Although the work of Bessemer and Siemens provided simple and effective moans for converting pig iron into steel and established the ""blast-furnace route"" as the almost universal method of producing steel, metallurgists have not ceased to dream of direct steel. By direct steel is meant any process by which iron oxide in ore is reduced to Iron of the same or greater purity than the final steel or wrought iron. That is, carbon or alloying elements would be added as needed, not reduced in unwanted quantities into the iron and then removed more or completely by refining (Bessemer or open hearth) only to be readded in desired quantities.In general, direct-steel processes are ""sponge-iron"" processes, because reducing iron oxide without simultaneously alloying the iron with carbon, phcophorus, sulfur, and silicon present in ore and fuel succeeds only if the temperature is below the melting point of the iron. Such solid iron formed by reduction of iron oxide at relatively low temperature is sponge iron, which is butlery and porous. When the reduction proceeds at the higher temperature at which the particles of metal can weld together or finally even melt to yield pellets or balls that do not have the porosity and low-density characteristic of sponge iron, the product might preferably be called simply ""direct iron."""

Jan 1, 1945