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By Douglas Ketcham, Thomas Jetzer

While the neurological and vascular aspects of Hand-Arm Vibration Syndrome (HAVS) has been generally accepted as a medical condition, the medical criteria and the clinical findings used to establish the diagnosis has been more difficult to bring to consensus. The criteria was first quantified by the Taylor-Palmear scale.1 This criteria was subsequently modified in 1986 at the 1st Stockholm Workshop2,3 to included more acceptance for the neurological effects that characterized the predominate findings in some workers. The relationship between hand-arm vibration and Carpal Tunnel Syndrome was defined in NIOSH 97-1414. While the aforementioned documents have defined the clinical entities associated with hand-arm vibration exposure, agreement on the clinical findings and test to confirm the diagnosis has be been more difficult to bring to consensus. Clinicians assessing HAVS has relied on a number of varied neurological and vascular tests. The neurological testing has focused on assessing damage to the sensory capability of the fingers for the neurological component including tests to measuring ability to sense vibration, cold or other end point finger sensor functions. However, the vascular testing has been traditionally focused on the ability to either measure vascular function or to reproduce the vascular blanching that occurs in HAVS with cold water provocation. Recent assessment of this testing in the United Kingdom Coal Miner’s study has questioned the value of this testing especially in reviews by McGeoch.5 In an attempt to provide some type of definitive testing to substantiate vascular damage from hand-arm vibration exposure, angiography is an alternative or adjunct to cold water provocation testing. The standards that have been established to predict the level, type and incidence of HAVS have been based on clinical studies and reports that have essentially been all male populations. However, the recent entry of women into more vibration intensive jobs has brought about the exposure of some women to high levels of vibration previously only previously experienced by men. However, there have been only few studies that look at HAVS in women6. Although exposed the same vibration levels, it has not been clear that the latency and type of pathology of HAVS in women will be the same as for men. The purpose of this study is to look at recent case studies of men and women exposed to jobs with high levels of hand-arm vibration with extensive clinical testing for both the neurological and vascular components of HAVS as well as other associated upper extremity conditions such as Carpal Tunnel Syndrome.

Jan 6, 2006

By Neil J. Mansfield

Tool manufacturers are required to provide declarations of vibration emission values in order to sell their tools within Europe. To ensure that users can compare results obtained from different manufacturers, the declared values must be obtained using a methodology as specified in the relevant test code (such as in the ISO 8662 series of standards). In most cases, the vibration emission values obtained using test codes under-estimate the vibration that an operator will be exposed to when using the tool on a work-site. A further problem with manufacturers’ data is that usually only a single value is provided for a tool. This is despite many factors affecting the vibration emission, including inserted tool type, work piece, operator technique, tool condition. New improved test codes are in the process of being developed. In order to provide guidance to users on how to interpret manufacturers’ data, a Draft CEN Technical Report (Draft CEN/TR 15350 (2005)) was developed. Part of the CEN/TR provides multiplication factors for combinations of task and tool type. For example, data obtained from electrical hammer drills (tested according to EN 60745-2-6:2003) should be multiplied by 2, for hammering applications, in order to obtain an estimate of the vibration emission during work. In response to concerns from industry, the UK trade association OPERC have, in collaboration with hire companies and tool manufacturers, established a freely accessible online database of tool emission values based on independent tests carried out under simulated work-site conditions. This paper reports some of the data obtained from electrical hammer drills, highlighting the range of emission values that can be obtained for a tool. Data from many other tool types are also included in the database. Methods Tri-axial hand-arm vibration was measured at both handles of each of 19 electrical hammer drills, in accordance with ISO 5349-1 (2001). Each tool was measured with three experienced operators and at least 5 runs were completed for each operator. Tools were tested using a range of appropriate new bits from 4 to 40 mm diameter. The minimum number of bits for a tool was 3; the maximum number was 29. 146 tool / bit combinations are reported here, representing about 2200 individual 6-axis measurements. Operators were required to drill vertically into a concrete block with a compressive strength after 28 days of 40 N/mm². Two drills (1 and 15) were battery powered; others were powered using a 110V transformer supply.

Jan 6, 2006

The State of Washington has a federal program that gives the Office of Surface Mining responsibility for assuring the reclamation of lands affected by coal mining. Most of Washington's coal-bearing regions lie west of the Cascade Mountains. The state's coal reserves are estimated at 1.4 billion tons, about 0.3 percent of the nation's total coal reserve. Steeply dipping. minable seams range from 2.5 to 25 feet in thickness. The occurrence of coal in Washington has been documented since the early days of its settlement; at one time, coal production played a significant role in the state's economy. During the late 1800s and early 1900s, coal was second only to lumber in Washington's industrial production. Coal production declined as other sources of energy were developed. By 1959, production was at 200,000 tons. Regulation of the coal mine operations in Washington is conducted by the Office of Surface Mining's Casper, Wyoming, Field Office and its local office in Olympia, Washington. All permit applications and abandoned mine land reclamation are completed by the OSM Western Support Center in Denver, Colorado. Inspections of mine and reclamation sites are conducted by OSM reclamation specialists located in Olympia.

Jan 1, 1992

By Donald Koch

The project investigated regional impacts of mining on the ground water system of the Powder River Basin by: 1) establishment of a regional ground water monitoring network. and 2)development at a set pit digital computer models to simulate ground water flow and quality, ground water contributions to surface water flow and quality (i.e., baseflow), and watershed run-off and recharge. Over 100 wells were monitored for physical and chemical parameters. Data were used as input to the models and for the development of a comprehensive data base. The basin was modeled on a regional and subregional scale using a finite -difference model employing an alternating difference technique. Two water-shed models were evaluated fur their ability to provide runoff and recharge inputs to the basic ground water model. Application of the regional and subregional models using conservative mining scenarios showed that drawdowns may extend west from the mines as far as ten miles but that impacts would be insignificant on a regional scale. The watershed model could be effectively applied to small watersheds only.

Jan 1, 1982

By Fred N. Kissell, Jerry C. J. Tien, Edward D. Thimons

At coal mine working faces, simultaneous application of three basic elements reduces the methane explosion hazard: (1) adequate ventilation, (2) regular monitoring of gas concentrations, and (3) the elimination of ignition sources. This paper reviews the application of these elements in a manner relevant to Chinese coal mines. Adequate ventilation is provided by using the mine entries to convey air for the long distances between the mine portal and the working sections (main ventilation systems) and then using line brattice or ventilation duct (face ventilation systems) to convey air the last hundred meters to the working face where coal is broken and removed. The air quantity provided is enough to safely dilute methane and the air velocity is enough to prevent layering. Gas concentrations are regularly monitored in accordance with regulations using knowledge of the circumstances under which the highest concentrations are likely to be found. Ignition sources are eliminated by ensuring that electrical equipment does not ignite methane, that sparking from cutter picks is minimized, and that smoking by workers is strictly forbidden. Risk-reduction studies using fault-tree analysis have shown that large reductions in explosion risk only result from multiple preventive actions. For example, a ventilation upgrade or a methane monitor upgrade by itself offers risk reductions under 50 pct. A risk reduction of 90 pct. or more would typically require much more. Other studies have shown that the everyday vigilance of those working underground is as important as engineering design.

By James R. Boyle

The value of Alabama's nonfuel mineral production in 1981 was $312.7 million, a decrease of $15.7 million from that of 1980. Output of most non fuel minerals declined; cement, crushed stone, lime, clays, and sand and gravel were the major commodities produced in the State. Alabama led the Nation in the production of crushed marble; was second in bauxite; third in native asphalt, kaolin, and oyster shell; fourth in bentonite, dimension marble, and fire clay; fifth in masonry cement; and sixth in common clay, ferroalloys, and lime.

Jan 1, 1983

By Robert C. Johnson

Domestic byproduct fluorine (in fluosilicic acid) availability at various price levels of aluminum fluoride were determined and a contingency availability curve developed. The supply of byproduct fluosilicic acid is restricted in amount to certain geographic regions, where plants processing phosphate rock are located, and the byproduct can be collected. The maximum possible U.S. annual supply, based on potential plant capacities, is 373,400 tons of fluosilicic acid containing 295,400 tons of fluorine. Based on inputs of 5, la, 25, 50, and 100 thousand tons per year, five levels of producing aluminum fluoride from fluosilicic acid (100 percent) were costed. Based on a 12-percent discounted cash flow rate, including the cost of salvaging the fluosilicic acid, the calculated selling price of aluminum fluoride ranged from $233 per ton to $448 per ton. At the higher price, 98 percent of the potential supply of byproduct fluosilicic acid could be used profitably; at the lower price only 46 percent could be used profitably.

Jan 1, 1973

By A. N. Baldwin

This report documents the work performed under Bureau of Mines Contract J0265029 to study and develop two innovative mining systems: ? An underground auger capable of augering into the right and left ribs without repositioning the machine ? A conventional mining system employing recently developed innovative machinery. The report is separated into two volumes to document the two studies separately. Volume I describes work performed and the recommended concept for a bidirectional auger. Volume II describes the studies of mining equipment performance and mining plans developed to determine a conventional mining plan offering improved productivity.

Jan 1, 1977

By Charles Vaught, JON VOLKWEIN, ROBERT PETERS, ERICA HALL

Since 1999, the CWP level among miners with 25 years or more experience, for instance, has risen from slightly more than 4% to 9% (See Figure 1). While it is obviously necessary to protect all miners’ lungs, there is now a technology to improve the chances that new miners’ lungs will be protected from the day they begin work.

By M. J. Sapko

The pressure and flame development of the methane-air-nitrogen system was investigated in the Bureau's l2-foot-diameter sphere to define buoyancy effects and to develop relationships for predicting venting requirements. Pressure rise (?P) is defined as a function of time (t) and nitrogen dilution and is shown to deviate noticeably from the cubic law (?P = kt3), depending upon the period of combustion and the mixture composition. Corresponding flame speed (Sf) and burning velocity (Su) data are given which show that Sf is time dependent and that Na dilution has a greater effect than air dilution in inhibiting the flame propagation. The Su data agree with "accepted" values and are unique in that they are based on much larger flames than those used in other investigations. Downward propagation limits are shown to depend mainly upon buoyant forces, which can affect the burning of even stoichiometric CH4-air systems. Theoretical expressions, based on the mixture burning velocity and expansion ratio, are given for predicting the venting requirements for ignitions of hydrocarbon-air-nitrogen mixtures in spherical or cubical enclosures.

Jan 1, 1976

The United States Bureau of Mines is establishing a computerized mineral inventory system to help the Federal Government appraise its mineral position and prepare programs insuring against critical shortages of materials. This system, called the Minerals Availability System (MAS), is a component of the Bureau's minerals intelligence function designed to conduct and maintain an inventory of minerals important to the Nation. The MAS defines the physical and commercial availability of the mineral resources. Known resources are evaluated and classified by deposit for entry into a computer storage and retrieval system. An integral concern of these evaluations is the cost of mining and beneficiating the ore contained in specific deposits. To meet this concern, a cost handbook was developed as an aid to preparing feasibility-type estimates for capital and operating costs of mining and primary beneficiation of various types of mineral occurrences. Cost data, obtained from U.S. and Canadian companies, were used as the basis of this handbook. The handbook presents cost curves and equations for each component of the mining and beneficiation process. Factors for each cost component are also given, thereby allowing the updating of cost for time, geographic location, labor rates, and mining and milling conditions. Included in the latter conditions are items such as the length of haul, need for rock bolts, and a rock work index for ores and rocks of various hardnesses. 1.2. USE OF THE HANDBOOK Using the handbook a feasibility-type estimate falling within 25% of expected actual cost is obtainable by summarizing cost components. This handbook should not be used to determine the cost of any single component of a mining or beneficiation system, as any single component may not fall within the 257 limit. It must be understood that anyone who uses the handbook must have a comprehensive knowledge of mining and processing technology and cost estimating procedures. The handbook was intended to be used internally by the Minerals Availability System. Because

Jan 1, 2012

The 1963 Lignite Symposium was held on the University of North Dakota campus, Grand Forks, N. Dak., April 30-May 1, 1963, under the cosponsorship of the University of North Dakota and the Bureau of Mines. This symposium, the third in a series, had as a general objective the dissemination of information concerning advances in technology and utilization of solid fuels, with emphasis on lignitic coals. Approximately 150 representatives of industry, government, and educational institutions from 21 states and 3 Canadian provinces were present at the symposium. Those attending were welcomed by Marling J. Ankeny, Director of the Bureau of Mines, representing the Bureau, and Dean T. H. Clifford, Vice President of the University, representing the University.

Jan 1, 1964

The 1963 Lignite Symposium was held on the University of North Dakota campus, Grand Forks, N. Dak., April 30-May 1, 1963, under the cosponsorship of the University of North Dakota and the Bureau of Mines. This symposium, the third in a series, had as a general objective the dissemination of information concerning advances in technology and utilization of solid fuels, with emphasis on lignitic coals. Approximately 150 representatives of industry, government, and educational institutions from 21 states and 3 Canadian provinces were present at the symposium. Those attending were welcomed by Marling J. Ankeny, Director of the Bureau of Mines, representing the Bureau, and Dean T. H. Clifford, Vice President of the University, representing the University.

Jan 1, 1964

By K. B. Lindsey

Geologically, the Williston Basin is a large structural depression of sedimentary rock in Montana, North Dakota, and South Dakota and Manitoba and Saskatchewan, Canada. The approximate It-mite of the basin are shown on figure 1; it is roughly circular with a diameter of about 400 miles and contains approximately 120,000 square miles. Although the petroleum potentialities in this area had long been recognized, it had not been vigorously prospected by the petroleum industry because of its geographic location, rigorous winters, depths to possibly productive zones, difficult geological problems, and the fact that more seemingly favorable areas were available for prospecting. With the discovery of oil near Edmonton, Alberta, in the prolific Devonian reefs, an incentive was given to explore for oil in the southeast extension of the same sedimentary trough, the Williston Basin. The Virden field discovery in southwestern Manitoba in January 1951 was a direct result of this southeastward movement. Discovery of this shallow field was followed soon after by discovery of' deep production on the Nesson anticline in North Dakota at Clarence Iverson No. 1 well. North Dakota then became the twenty-seventh petroleum-producing State.

Jan 1, 1954

By Robert H. Peters

This U.S. Bureau of Mines report identifies the types of serious accidents that occur most frequently at small underground coal mines and describes the strategies that could help prevent these accidents. A wide variety of methods for improving safety are suggested, including improvements in the design of equipment, work procedures, work schedules, safety programs, and emergency response plans, as well as techniques for diagnosing the potential hazards associated with new technologies and work procedures. Some of the papers in this volume focus on preventing specific types of mining accidents-ones associated with materials handling (primarily back injuries), equipment maintenance, improper machine guarding, and ground failure during retreat mining. Although the recommendations in this volume are heavily influenced by research performed at underground coal mines in the Appalachian coalfields, most of the papers contain advice that is equally pertinent to almost any type of mine.

Jan 1, 1994

By Steven J. Page, John A. Organiscak

Laboratory crushing experiments were conducted on a range of low- to high-volatile bituminous coals to investigate the various factors influencing airborne respirable dust (ARD) generation. This research was conducted to identify the principles of ARD liberation from the coal product. Five U.S. bituminous coals were uniformly prepared and processed through a double roll crusher located in a low-velocity wind tunnel. Experimental factors studied included inherent coal seam constituents, coal grind ability, specific energy of crushing, product size characteristics, dust cloud electrostatic field, and specific ARD generated. The results of this investigation indicate that a combination of several factors are associated with ARD generation. One factor is the effect of coal rank, described by the inherent moist fuel ratio, on the product size characteristics, defined by Schuhmann size function parameters. Another key factor is the effect of air dry loss(ADL) moisture in the coal seam on the breakage-induced electrostatic field of airborne dust. The effect of these factors is that different percentages of <10-m coal particles are dispersed as ARD. A discussion of electrostatic field principles, coal ADL, and its effect on ARD generation is presented.

Jan 10, 1998

By Joel N. Van Sant

THIS REPORT describes the occurrence, mining, and use of refractory clay in Colorado within Region III of the Federal Bureau of Mines, which includes the States of North arid South Dakota, Nebraska, Wyoming, Colorado, Utah, New Mexico, and Arizona. Field work by the Bureau of Mines, United States Department of the Interior, included examination of active and abandoned refractory-clay mines as well as a reconnaissance survey and sampling of numerous clay-bearing formations exposed in Colorado. Information from the survey and the sampling will help guide private industry in its search for virgin sources of refractory clay. Library research of published and unpublished reports from various Federal, State, and private sources was conducted during the early phase of the investigation. Most of the refractory clay mined in the Denver-Golden district of Colorado is not used for refractory purposes but is blended with other clays in the manufacture of structural clay products. The predominantly flint-clay de-posits in the Pueblo and Fremont County districts are mined and utilized chiefly in fabricating refractory products.

Jan 1, 1959

By Nancy Estrada, Jane Nowell, Cathy Jennings, Debra Yniguez, Carol Lavery, Kristin Harrer

Pilots of the MH-60S helicopter are exposed to continuous whole body vibration (WBV). Pilot fatigue is a growing operational concern due to the increased frequency of extended durations of missions (6-8+hours) in support of Operations Iraqi Freedom and Enduring Freedom. Endurance aspects of the currently used rotary wing seating systems were not optimized for the longer missions and wide range of pilot anthropometric measurements, which is now typical of naval aviation. The current seating systems were designed primarily to meet crashworthiness requirements, not for the wide range of pilot anthropometry or to mitigate WBV. Albeit, an issue, pilot fatigue and reduced mission effectiveness are also critical concerns. Current Hazard Reports indicated that pain in pilots’ legs and backs begin two to four hours into the flight and increase with time. Mission readiness also decreases with an increase in flight duration due to the constant distraction of pilots shifting in their seats while trying to get comfortable. Froom, et al [2] reported a dose-response relationship between the length of military helicopter flights and back discomfort. He also concluded that this pain is typically dull, over the lower back, and its prevalence and intensity are dependent on the total flight hours of exposure. Methods This study evaluated WBV produced in the pilot seating systems onboard the MH-60S. The purpose of the study was to test and compare the effectiveness of two different seat cushions, the current seat cushion versus an anti-vibration seat cushion. Both seat cushions were measured for acceleration levels averaged over five-minute intervals using a triaxial seat pad accelerometer. The recordings were completed for a 3-hour straight and level flight. A frequency analysis from 0-80 hertz (Hz) was conducted on all acceleration measurements to determine the dominant axis and frequency of the pilots’ vibration exposure. The results were then compared to the applicable Threshold Limit Values (TLVs) established by the American Conference of Governmental Industrial Hygienists (ACGIH) [1] and the International Organization for Standardization (ISO) 2631.1 [3] to determine the MH-60S pilots’ permissible exposure time for both seat cushions. Results The results of the study showed that for both seat cushions the vibration levels of the z-axis at 16 Hz had the shortest allowable exposure duration, according to the ACGIH TLVs. In the z-axis at 16 Hz, the MH-60S’s current seat cushion’s acceleration levels indicated an exposure time limit of approximately 6 hours, while the anti-vibration seat cushion’s acceleration levels pierced the 8-hour exposure time limit curve. This is shown in the graph below.

Jan 6, 2006

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Jan 1, 1980

The coal-bearing regions of Colorado cover approximately 29,600 square miles, which is 28.4 percent of the state&apos;s total area. The most important coal-bearing regions are located in the north western and west-central parts of Colorado. Coal resources vary from lignite to anthracite. More than 70 percent are bituminous; 23 percent subbituminous; 5 percent lignite; and less than 1 percent anthracite. The state&apos;s coal reserves total about 17.2 billion tons, 3.5 percent of national reserves. Approximately 8.8 million acres of coal rights in the state are owned by the Federal Government; on about 72percent of this land, the Federal Government controls both the coal and the surface rights. It is estimated that approximately 4.2 billion tons of coal reserves are under federal ownership in Colorado. Permitted acreage of mines in Colorado ranges from 40 to 13,114 acres. Differences in elevation create many climatic zones in Colorado. Local annual precipitation can average less than eight inches in some areas in extreme western Colorado to more than 30 inches in certain mountainous areas. Generally, precipitation rates are low at most mine sites, making revegetation difficult. Colorado gained primacy when its regulatory program was conditionally approved December 15,1980. The Abandoned Mine Land Program was approved June 11, 1982.

Jan 1, 1992