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By G. Roger Miller, Kristine M. Krajnak, Stephen S. Leonard, Stacey Waugh

Repeated exposure to hand-arm vibration through the use of vibrating hand tools can result in the development of the disorder known as hand-arm vibration syndrome (HAVS; (1,3)). One of the hallmark symptoms of HAVS is cold-induced peripheral vasospasms that result in finger blanching (4). Although the vascular and neural pathology associated with vasospasms has been described, little is known about cellular mechanisms leading to this damage (4). To understand how vibration may alter vascular and neural physiology and anatomy, rats were exposed to a single bout of tail vibration and the molecular responses of neural and vascular tissues were measured to determine if there are immediate or sustained affects of vibration that may underlie longer term changes in physiology. Methods Experiment 1. Male Sprague Dawley rats (n = 32, 6 weeks of age) were housed in AAALAC accredited facilities. All procedures were approved by the NIOSH Animal Care and Use Committee and were in compliance with the CDC guidelines for care and use of laboratory animals. Vibration exposures were performed by restraining rats in Broome-style restrainers, and securing their tails to a vibration platform using 6 mm wide straps that were placed over the tail every 3 cm. Restraint control rats were treated in the same manner, except that the tail platform was mounted on isolation blocks and not on a shaker. The vibration exposure was 125 Hz, 49 m/s2, for 4 h. Rats were euthanized with an overdose of pentobarbital (100 mg/kg) 1 h or 24 hours after the exposure. RTqPCR was used to measure transcript levels for endothelin 1 (ET-1), the 3 forms of nitric oxide synthetase (NOS) NOS-1, NOS-2, NOS-3 and norepinephrine receptor subtypes 1D, 2A, 2C, in artery tissue, and to measure calcitonin gene-related peptide (CGRP) and nitric oxide synthase-1 (NOS-1) in ventral nerves. Data were analyzed using 2-way ANOVAs. Experiment 2. Male Sprague Dawley rats (n =24, 6 weeks of age) were maintained as described above. Animals were exposed to a single bout of restraint or vibration. Another group of animals served as cage controls. All animals were euthanized 24 h after the exposure, and tail arteries were isolated and frozen. Reactive oxygen species ROS) were measured using electron spin resonance spectroscopy (ESR). Arteries were homogenized over ice in 1 ml of PBS with protease inhibitor cocktail, using a tissue tearer (Biospecs Products Inc. Racine, WI USA). The sample was split into two 0.5 ml samples. One set had PBS and the spin label hydroxyl-TEMPO [0.1 mM] added while the other set had hydroxyl-TEMPO [1.0 mM] plus the specific hydroxyl radical scavenger, dimethylthiourea (DMTU), added to confirm the presence of the hydroxyl radical. Samples were vortexed and then placed in a flat cell for ESR analysis. The ESR spectrometer settings were: receiver gain, 6.32 x 102; time constant, 0.02 s; modulation amplitude, 1.0 G; scan time, 20 sec; magnetic field, 3490 ± 100 G (2). Data were analyzed using 1-way ANOVAs.

Jan 6, 2006

This Bureau of Mines report describes research on methods of assuring the continued safety of mine electrical power distribution circuits through reliability and quality assessment of the protective devices, innovative inspection techniques for these devices and the circuits themselves, novel applications of trolley line circuit breakers, and computer modeling of distribution systems to determine the proper ratings for cables, power sources, and circuit protective elements. Battery charger safety is included.

Jan 1, 1979

By David A. Hill

This volume contains a summary of the results of past analyses on U.S. Bureau of Mines Contract No. 80122061 which are relevant to electromagnetic location in mine rescue situations. The analytical results indicated that detection of a trapped miner equipped with a special transmitter is feasible in most situations. Location of the miner by surface measurements is also generally feasible within certain errors. The feasibility of miner detection and the accuracy of miner location have been examined theoretically for a wide variety of situations. Agreement with experimental results is generally good in cases where measurements are available. Personnel involved in the investigation include J.R. Wait (Principal Investigator), D.A. Hill (Co-Principal Investigator), K.P. Spies, A.Q. Howard, and Lana Slusher (Administrative Assistant).

Jan 1, 1974

By I. F. Avery

The productive capacity of natural-gasoline and cycling plants in the United States on January 1, 1958, was 48.8 million gallons per day, according to the Bureau of Mines biennial survey. This represented an increase of 2.4 million gallons per day during the 2-year period since the last survey. In the previous 2-year period, capacity had increased 7.5 million gallons per day. The major increase in operating capacity occurred in Texas and New Mexico. In New Mexico, capacity increased 43 percent. The total number of plants decreased from 600 on January 1, 1956, to 584 on January 1, 1958. The number of operating plants decreased from 571 to 558. Five new plants were completed in Colorado, increasing the number of operating plants from 7 to 12.

Jan 1, 1958

By Richard L. Unger

The Bureau of Mines entered into a cooperative agreement with an eastern Kentucky coal mining company to comprehensively redesign the flow of equipment and supplies throughout its underground mines. Items were tracked from delivery to the warehouse and from surface storage areas to their final usage locations underground. Three underground mines were visited, and a great variety of tasks were videotaped for subsequent laboratory analysis. Of particular interest were tasks that required manual handling of the supplies or equipment components. Activities such as handling daily supplies (concrete blocks, rock dust, and cross- beams) and handling or lifting the continuous miner power cable were determined to be the most hazardous. Recommendations to the company included redesigned surface storage areas to facilitate the use of forklift vehicles to load the underground supply cars. Designs were also developed for different mechanical- assist devices to help in unloading the supply cars underground and to handle equipment maintenance tasks underground. Additionally, the videotapes of the underground manual handling tasks became the basis for simulating those activities in controlled laboratory conditions. This testing will contribute to developing guidelines for proper lifting techniques for low-seam coal mines.

Jan 1, 1986

By P. -É. Boileau, M. Smets, T. Eger, J. Boutin

Long-haul dump (LHD) vehicles used in underground mining are known to expose workers to important levels of whole-body vibration1. These vehicles are generally designed without suspension and may be categorized as small or large LHDs depending on whether their respective load capacities are lower or larger than 3.5 cubic yards. While the majority of older vehicles are equipped with a rigid or unsuspended seat, more recent LHDs often incorporate a suspension seat. The objective of this study was to define the vibration spectral characteristics of most commonly encountered large and small LHD vehicles operating in mining operations. This was done in an effort to categorize the vehicles in terms of vibration spectral classes to be reproduced on a laboratory whole-body vibration simulator to assess the vibration attenuation performance of a typical LHD suspension seat. Methods Vertical vibration measured at the seat attachment point of 8 small and 8 large LHD vehicles operating underground in typical mining operations under loaded and unloaded conditions was considered as the basis for defining the spectral classes. By regrouping the data collected for each LHD vehicle size and load condition, the overall distribution of acceleration power spectral density (PSD) of measured floor vibration was determined over the 0.5 to 20 Hz frequency range. Mean and envelopes of maximum and minimum values of PSD spectra were computed to define the spectral classes, along with the corresponding values of frequency weighted rms acceleration determined in accordance to the ISO 2631-1 standard2. These spectra were further used to calculate the displacements needed to drive a whole-body vibration simulator consisting of a platform supported by two servo-hydraulic actuators having a total stroke of ±100 mm. For validation purposes, the vibration acceleration spectra measured on the simulator were compared with the target spectra representing the spectral classes. Finally, the vibration transmissibility characteristics of a typical suspension seat were determined under sine sweep excitation using both a rigid mass load and a human subject having a mass of 62 kg and 85 kg, respectively. The SEAT value, representing the ratio of seat to base frequency-weighted rms acceleration, was further measured under each of the defined LHD vibration spectral classes by loading the seat with an 85 kg subject. Tests were repeated three times and the mean SEAT values were determined to assess the seat’s ability to reduce exposure to whole-body vibration in LHD vehicles. Results Three spectral classes applicable to both loaded and unloaded conditions were defined as shown in Figure 1: one for large and two for small LHDs. The influence of load on frequency-weighted rms acceleration was found to be negligible for large and Class I small LHDs, while a shift of the peak acceleration PSD to lower frequencies was noted for the loaded vehicles. The influence of load was found to be more important for Class II small LHDs. Table 1 provides a

Jan 6, 2006

The strippable reserves of bituminous coal and lignite in the United States were calculated in accordance with the prevailing conditions of seam thickness and depth of overburden in each of the several coal-producing areas of the Nation. Within defined limits of seam thickness and depth of overburden, it is estimated that there was a remaining strippable resource of 118 billion tons of raw bituminous coal and lignite as of January 1, 1968. Because of topography, natural and manmade features, and other limitations, only 45 billion tons of the resource are strippable reserves. Of this, 32 billion tons is considered low-sulfur (less than 1 percent), 4 billion tons is medium-sulfur (1 to 2 percent), and 9 billion tons is high-sulfur (over 2 percent) coal. Owing to a cleaning loss affecting that portion of strip coal that is mechanically cleaned, the 45 billion tons of strippable reserves are reduced to 39.6 billion tons of marketable coal. A brief discussion is given for each coal-producing State, summarizing past and present production, historical background, and outlook. Appendix A contains reserve data by State, county, seam, and sulfur content. Appendix B contains the general information and requirements necessary to comply with the current strip mining laws covering 20 States.

Jan 1, 1971

This report, the third in an annual series, outlines recent trends and developments in the minerals industry. Discussed are new methods, equipment, techniques, and systems used to more, effectively extract and process minerals and fuels. Environmental considerations, reduced ore grades, and the related increased quantities of material handled were the dominent concerns of the minerals industry in 1972. Productivity increased in most mineral commodities as equipment became more mobile, versatile, and sophisticated. Increasingly, equipment designs incorporated health and safety features. There was considerable interest in the field of energy and in pollution-free metallurgy processes.

Jan 1, 1973

By Charles C. Boley

High-volatile A bituminous coal from the Allen mine, Las Animas County, Colo., blended with char produced from the same coal yielded accept-able metallurgical coke in a 500-lb movable-wall test oven. Nineteen experimental runs were carried out using several concentration levels of two different chars, 5.6 and 19.6 percent volatile matter, produced by entrainment carbonization of the base coal. With the higher-volatile char, an acceptable coke was produced at a 22.5-percent concentration; the lower-volatile char did not produce an acceptable coke at the concentrations investigated.

Jan 1, 1972

By D. R. Flinn

A newly developed chemical conditioning technique, which greatly simplifies the preparation of plating baths for the electrodeposition of titanium diboride (TiB2) coatings, is described in this report. The new plating technique was used to prepare samples of titanium diboride (TiB2) coatings on three types of substrate materials. These samples were then evaluated in both low- and high-speed wear-test programs to determine the wear resistance, microhardness, and adhesion of the coatings. In general, it was found that the wear resistance of the coatings is independent of substrate. Scanning electron micrographs have shown that the coating wear surfaces are very smooth, suggesting slow and continuous removal of the coating during the wear test (that is, adhesive wear). Adhesion between the coating and all substrates was excellent. Microhardness results show that the TiB2 coating is harder than alumina, with a hardness value exceeding 5,000 kg/mm2 measured in one test. The results of the wear tests show that TiB2 coatings have relatively poor wear resistance compared with alumina in low-speed unlubricated sliding environments, but exhibit wear properties comparable with alumina in high-speed unlubricated sliding environments.

Jan 1, 1981

By H. H. Schrenk

One phase of the Bureau of Minest work in the field of health and safety is the promotion of safe, satisfactory, and reliable respir atory protective devices. To insure that such devices will be available, the Bureau has established schedules of what it considers the minimum re- quirements for oxygen breathing-apparatus,3 gas masks, hose masks,5/ and mechanical filter-respirators (a schedule of requirements for hose- type supplied-air respirators is being prepared). Approval of oxygen breathing-apparatus is given by the Safety Division; approval of other types of respiratory equipment is given by the Health Division, both divisions being in the Health and Safety Branch, Manufacturers of respiratory protective devices may submit their equipment to the Bureau for approval under the requirements of these schedules. As a prerequisite to submitting a device for approval, the Bureau requires a statement that the device is completely developed and of the design and material that the manufacturer believes suitable for a finished marketable device; that the device has been

Aug 1, 1937

By F. A. Jones

Increased mechanization .of coal mines has emphasized the need for study of actual power requirements of the various machines employed in the production of coal and losses in the distribution of power to these machines. These studies are being made in order that hazards, excessive use of power, and high maintenance cost of equipment resulting from these losses may be analyzed and eliminated where possible. Research on the use of electric power in-coal mines was suggested by the Advisory Committee of the Bureau of Mines in 1937, and it was decided to begin with a study of individual machines of various types under operating conditions in modern coal mines. The transmission of power, particularly line losses and inadequate return circuits, should be a part of the investigation. This report presents some of the data of an initial study in commercial mines. ACKNOWLEDGMENTS The superintendents, engineers, and other officials of the two mines studied cooperated fully and aided in setting up and transporting the test equipment, giving such information as was requested.

Jan 1, 1942

By E. M. SEELEY, F. S. LOTT

The total capacity of the natural-gasoline industry to produce light hydrocarbon products increased to 21,322,000 gallons ( 507,670 barrels ) daily on January 1 , 1948 , from 17,928,000 gallons ( 426,860 barrels ) daily on January 1 , 1946. Expansion of the industry in the first two post -war years , 1946 end 1947 , thus averaged 9 percent annually , compared with 6 percent annually in the last two war years , 1944 and 1945 . The number of cycle plants increased only from 37 to 39 in the years 1946 and 1947 , and total capacity of these plants gained 21 percent to 5,857,000 gallons de ily on January 1 , 1948 , represent ing 27.5 percent of the total capacity of the industry , compared with 27.0 percent on January 1 , 1946. All other plants decreased in number in the two-year period from 589 to 510 on January 1 , 1948 , but their total daily capacity increased 18 percent to 15,465,000 gallons . The daily capacity of the average plant in the industry was enlarged from 28,600 gallons on January 1 , 1946 , to 38,800 gallons on January 1 , 1948 , continuing the long -established trend to producing units of greater size and efficiency . The average cycle plant capacity increased from 131,000 gallons daily to 150,200 gallons daily on the same dates as the average capacity of all other natural -gasoline plants increased from 22,200 gallons to 30,300 gallons . Owing to the elimination of small , obsolescent plants in Illinois , Oklahoma , and Pennsylvania , these States experienced the greatest reductions in numbers of plants in 1946 and 1947. In Oklahoma and Texas , several consolidations of two or more plants into a single operating unit were reported . Louisiana and Mississippi were the only States in which the number of plants increased , but daily capacity to produce light products was larger in eleven States on January 1 , 1948, than two years earlier . Added facilities in California and Texas accounted for 41 and 36 percent , respectively, of the national gain in capacity .

Sep 1, 1948

By J. M. Singer

In this Bureau of Mines study coal and rock dust beds were entrained by airblasts generated by gas explosions at the closed end of a 0.61-m-diameter explosion tunnel, 49.7 m long. The system was designed to simulate entrainment of mine dust deposits by accidental gas explosion at the coal face of nonintersecting mine passageways. Full-scale mine explosion trials confirmed many of the results of the explosion tunnel experiments and indicated several new features of dust entrainment. Dispersal of 20.3-cm-long stepped dust beds located 35 m from the closed end always began during the early portion of the ascending gradient of the first transient airflow (and pressure) wave, and was usually completed before the end of the first quarter-wave period. Bulk quantities of dust were entrained simultaneously by longitudinal regression from the leading edge of the dust bed and by surface lifting of the top layer. Instantaneous threshold air velocities for bulk quantities of coal and rock dust beds in separate, mixed, and layered configurations were in the same range (5 to 30 m/sec) as previously found under steady-state velocity conditions. Selective lifting of coal dust layers from rock dust occurred when the threshold dispersal velocity of coal dust but not of the underlying rock dust was exceeded.

Jan 1, 1976

By C. H. Bloomster

This study estimated (1) radon and radon daughter emissions from underground uranium mines; (2) the reduction in radon that would be released to the surface by using control techniques such as bulkheads, sealants, backfilling, and positive pressure ventilation; (3) the cost for radon and radon daughter removal from total exhaust air; and (4) total radon and radon daughter discharge for lower occupational exposure limits. For 13 large underground uranium mines, estimated yearly radon emissions from each mine ranged from 900 to 3,400 Ci. The estimated age of air emitted from the mines ranged from 11 to 37 min. Potential radon removal methods for the total mine exhaust were evaluated. The cost of these methods was prohibitive. Diurnal and seasonal changes may affect radon emission over short periods of time, but do not affect the total emissions over the long run. Radon and radon daughter emissions would be little changed by increased ventilation requirements needed to achieve lower occupational exposure limits. The concentrations in the exhaust would be lower, but the total release would be the same

Jan 1, 1984

By Martin D. Conyac

A 1984 Bureau of Mines investigation identified ho mineral resources in the Wilderness Study Area (WSA). However, four prospects in the WSA contain anomalous amounts of copper and silver minerals; one had traces of gold. Stratabound copper-silver occurrences appear to be prevalent. Quartz veins in the WSA locally contain trace gold, and one mine adjacent to the area produced some gold in the late 1800's. The WSA is underlain principally by Precambrian and early to middle Paleozoic quartzites, argillites, dolomites and limestones that have been complicated by faulting, generally tilted northeastward, and thrust southeastward over sequences of late Paleozoic sedimentary rocks. The stratabound copper-silver occurrences and gold-quartz veins are in Precambrian and Cambrian rocks in the western part of the WSA, as are similar deposits regionally. Sand and gravel, and limestone are abundant, but plentiful resources of these commodities are nearer established markets. In November 1983 there were 5 small groups of current claims oh the WSA boundary; none are patented claims. Probably less than 35 claims have been located within the WSA, mostly in the northwestern portion; hut over 100 claims have been located outside, near the northwestern boundary. Oil and gas leases nearly surround the boundary and 6 extend up to 1 mile into the study area. There has been no recorded mineral production from within the WSA. From 3 to 5 miles to the west, several lode nines in the Johnnie district have produced several million dollars worth of gold from quartz veins, and some silver and lead from galena-calcite veins. These veins generally trend northeasterly and dip northwesterly and probably do hot extend into the study area.

Jan 1, 1985

By Raymond W. Hiteshue

To aid in designing a continuous system for evaluating processes for converting coal to high-Btu gas] the Bureau of Mines determined the amenability of various coals and a char to hydrogasification at 800° C and 6,000 psig using a molybdenum catalyst. A lignite from Rockdale, Tex., an hvCb coal from Rock Springs, Wyo., a char from the low-temperature carbonization of the latter, an hvAb coal from Pittsburgh, Pa., and an anthracite from Luzerne County, Pa., were selected. Highest yields of gaseous hydrocarbons, 94 pet, based on maf feed, were produced from char, and lowest yields, 67 pct, were obtained from lignite. Hydrocarbon gases contained 82 to 92 pct methane, 8 to 15 pct ethane; and 1 to 3 pct propane.

Jan 1, 1962

By E. J. Matson

"The Bureau of Mines has been investigating deposits of critical and essential minerals in the United States since 1939. Projects were set up on only the most promising properties.A preliminary examination of the Mount Hope mine was made in January 1943 by the Bureau's engineers, who recommended exploration by diamond drilling.The mine is in the unsurveyed portion of T. 22 N., R. 1 E., Mount Diablo base and meridian, south-central Eureka County, Nevada, 25 miles by road north of the village of Eureka. A partly graded and Graveled secondary road connects the mine and Eureka on U. S. Highway 50.Extensive sampling was done by the Bureau in February. 1943. Core drilling from the surface was started on March 15, 1944, and completed on April 2, 1545. The 16 holes drilled totaled 7,215 feet. The mining company also did extensive underground core drilling from April 21, 1944, to January 4, 1945. This report gives the results of core drilling supervised by the Bureau of Mines.The drilling program was designed to explore for extensions of the mineralization exposed in the mine workings. As a result of drilling, additional ore was found, and it is believed that this project has fulfilled the purpose for which it was planned.In its program of exploration of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization, of our mineral resources to the end that they make the greatest possible contribution to na¬tional security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, R. G. Knickerbocker, chief, analyzes samples of ore and performs beneficiation test. Both these branches are under the supervision of Dr. R. S. Dean, assists director.With respect to this report special acknowledgment is due to Charles W. Merriam of the United States Geological Survey for his interpretation of the Mount Hope mine Geology and his cooperation throughout the project; Col. Leverett Davis, former lessee of the property; K. K. Hood, manager of the Mount Hope Unit, Callahan Zinc-Lead Co., Inc.; C. P. Knaebel, assistant manager, and M. P. Nackowski, geologist, of that company, for their help, and to the Sullivan Machinery Co. for its assistance."

Aug 1, 1946

By F. A. Jones

Increased mechanization .of coal mines has emphasized the need for study of actual power requirements of the various machines employed in the production of coal and losses in the distribution of power to these machines. These studies are being made in order that hazards, excessive use of power, and high maintenance cost of equipment resulting from these losses may be analyzed and eliminated where possible. Research on the use of electric power in-coal mines was suggested by the Advisory Committee of the Bureau of Mines in 1937, and it was decided to begin with a study of individual machines of various types under operating conditions in modern coal mines. The transmission of power, particularly line losses and inadequate return circuits, should be a part of the investigation. This report presents some of the data of an initial study in commercial mines. ACKNOWLEDGMENTS The superintendents, engineers, and other officials of the two mines studied cooperated fully and aided in setting up and transporting the test equipment, giving such information as was requested.

Jan 1, 1942

By S. S. Clarke

This paper on methods and costs of mining at the Westside mine, in the Tri-State zinc-and lead-mining district (Missouri-Kansas-Oklahoma), is one of a series being prepared by the Bureau of Mines on mining practices, methods, and costs in various mining districts of the United States. Methods and equipment used in drilling, loading, and underground transportation have changed radically since the latest Bureau of Mines publications2/ on mining methods in the district were published more than 20 years ago. More efficient methods and machines have been developed in order to maintain low operating costs in the face of rising labor and supply costs and lower grade ore. The rate of conversion to mine mechanization was disappointing at times; local conditions required the development of special equipment, and available rock-moving machines had to be remodeled and strengthened.

Jan 1, 1957