Search Documents

By N. Grosland, G. Kopp, T. Hunstad, D. Wilder, M. Contratto, S. Rahmatalla, T. Xia

Chronic whole-body vibration exposure, as expected in large construction and mining vehicles, has been associated with neck and back pain and injury.1 While work has been done towards gaining a better understanding of the relationship between vibration and shock and muscle activity of the back musculature2, relatively little information regarding the activity of neck, shoulder and upper arm muscles is known. Today’s equipment designs must conform to domestic and international standards, however these standards do not specifically address the vibration exposure in the head and upper quarter. Further it is not well known how the control configuration within a vehicle (e.g. steering wheel versus arm controls) influences muscle voluntary and reflex activity levels. Greater muscle activity may lead to greater muscle fatigue – which in turn may be associated with greater risk of injury.2 Thus, muscle contractions needed to maintain static postures as well as those resulting reflexively should be considered during an analysis of seating position. Unfortunately, little is known regarding the influence of arm position on head and neck muscle function. The purpose of this study was to investigate the relative muscle activities of 5 neck, shoulder, and upper arm muscles during riding simulations of large construction equipment, using three different arm control options. Methods Five typical heavy equipment ride files were “played back” through a man-rated Servo Test 6-degree of freedom (dof) vibration system. Each ride was repeated using 3 seat and control configurations (steering wheel (SW), floor mounted arm-rest controls (FM), seat mounted arm-rest controls (SM)). Two trials were performed for each ride and seat control combination (each trial: 60 sec of 6-dof and 60 sec of vertical vibration). Five channels of surface electromyography (EMG) of the right-side cervical erector spinae muscles (neck extensors), sternocleidomastoid (neck flexor), upper trapezius (shoulder elevator), biceps brachii (elbow flexor) and triceps brachii (elbow extensor) muscles were collected throughout each ride (~ 2min) using pre-amplified (10x), 1 cm silver bar electrodes, with 1 cm fixed inter-electrode distances (Delsys, Inc). Further analog amplification was set at 10k (1k for one subject), and sampled at 1000Hz using a 12-bit DAQ card and Labview 7.1 software (National Instruments). A total of 7 right-handed male subjects were tested, but only 5 had complete EMG data sets to analyze for this sub-study. EMG was analyzed using root mean square (RMS, in mV) of 20 ms moving windows, and then averaged across the entire trial for a measure of mean total muscle activity (voluntary and reflexive). The muscle activity to maintain the static posture was estimated as the mean RMS EMG over a 1 sec interval just prior to and/or after completion of the ride. Repeated Measures ANOVAs were used to test for with-in subject differences using a = 0.05.

Jan 6, 2006

By Daniel G. DiCanio

This report describes a computer-based model for estimating the tangible costs of injuries and deaths from work-related accidents in underground coal mines. The study undertook to identify and quantify the elements of accident costs, including field visits to coal mines, insurance carriers, and public agencies. The mathematical models developed for each tangible element of accident cost are presented in Volume I of the report. A listing of the computer programs which comprise the model and instructions for using the programs are presented in Volume II. Statistical distributions of mining family characteristics, data on 95 miners killed in underground accidents, and other basic data used to develop the model are presented in Volume III. Application of the model to a data base of 9,286 accidents which occured in underground bituminous coal mines during 1974 yielded a total of $56,900,000 in tangible costs to industry, mining families, and public agencies. Loss of income to the families of miners injured or killed in these accidents accounted for 47 percent of the total.

Jan 1, 1976

By Wesley G. Holtz

A project to demonstrate the feasibility of retorting oil shale by the Paraho vertical retort process was carried out at Anvil Points, Colorado during 1974 to 1976. As a part of the demonstration project, laboratory and field tests were performed to determine the physical and chemical properties of the retorted shale for use in the development of eventual full-scale disposal plans. The material which exits from the Paraho retort is classified as a non-plastic silty gravel by the Unified Soil Classification System. The particles have an apparent specific gravity averaging near 2.60 and a mass specific gravity averaging near 2.00. The material can be compacted by normal laboratory and field construction methods to about 90 to 100 pounds per cubic foot dry density depending upon the degree of compactive effort applied. The addition of moisture does not improve compactibility appreciably. When high compactive effort is applied the retorted shale is classed as impervious to water flow. The compacted retorted shale exhibits shear strengths in the same order as those observed for silty gravel soils. If the compacted material is cured (long tune simulation testing) prior to strength testing considerable strength gain can be obtained from cementing action. The amount of cementing developed is dependent upon heat treatment and other operating modes of the retort.

Jan 1, 1976

By Robert F. Randolph

Real-world levels of attenuation from hearing protection devices are usually much lower than the rated values obtained under near-ideal circumstances. The shortfall is even more extreme for earplugs than it is for earmuffs, primarily because of the complicated process of fitting the plugs within the ear canal. This study examines the use of a commercially-available lubricant for hearing aids to determine whether it would facilitate improved fit and attenuation for earplugs. In this experiment, ten participants inserted earplugs with and without using the lubricant. Average attenuation was assessed with the Real-Ear-Attenuation-at-Threshold (REAT) technique, and showed over 5 dB improvement when the lubricant was used. Participants obtained an 85% mastery rate using the lubricant versus a 50% mastery rate without. These results indicate several possible applications for improved earplug performance in real-world settings where hazardous noise is unavoidable and effective hearing protection is necessary.

Jan 1, 2008

By V. Ferrari

This report documents the three-phase program to design, fabricate, test, and demonstrate economical and practical methods of reducing noise levels on underground coal mining portal buses (mantrip vehicles). The noise-control treatments applied to a production-model portal bus were as follows: ? Wheel/rail vibrations were isolated from the vehicle frame by inserting elastomeric materials between suspension components. ? Vibration-induced noise was reduced by replacing all large sheet metal panels (except floor plates) with damped steel panels. ? Motor noise was reduced by tight-fitting covers made from damped steel and lined with sound-absorbing material, and by elastomeric motor mounts. ? The standard spur gears used in the traction drive system were replaced with helical gearsets. The program achieved the goal of reducing the average sound-level to below 85 dBA for typical operating conditions.

Jan 1, 1981

By A. Renton Amell

The rate of dissolution of U02 was measured in acid solutions similar to those used for in situ leaching, with S04 of 10-1.82 to 10-4 M, Fe(III) of 10-2 to 10-4 M and pH's of 1.1 to 2.3. The dependence of dissolution rate on pH was small and inconsistent, probably reflecting the combined effects of a very weakly polar oxidizing complex, probably FeSO4+, and a nearly neutral U02 surface. Differences in the state of the U02 surface may explain this variability as well as contrasts between these results and results reported in other work. Changing either S04 or Fe(III) concentrations significantly affects dissolution rates. Increasing low sulfate concentrations in solutions containing 10 2 M Fe(III) at pH 2 results in formation of FeSO4+. In such solutions, rates increased with (S04)/(Fe(III)) up to 1:30, thereby indicating that the oxidation of U02 by FeSO4 is more rapid than by Fe3+. However, the dissolution rate decreased at higher (SO4)/ (Fe(III)), due either to sorption of SO42- on the UO2 surface or to formation of other less reactive sulfate complexes such as Fe(S04)2 or FeHSO4+ However, Fe(III) concentration is the dominant factor in determining solution rates. The rate was directly proportional to ferric iron concentration, indicating that the rate-determining step of the dissolution reaction is a single-electron oxidation by a ferric complex. Dissolution rates were lower in solutions of 0.1 and 1.0% H202 (0.029 and 0.29 M) than at similar concentrations of ferric iron because of formation of an insoluble surface coating of uranium peroxide, UO4?4H20. This phase may limit the value of hydrogen peroxide as an oxidant in lixiviants, not only by its very low solubility, but perhaps also by filling pores and reducing permeability in the ore body.

Jan 1, 1978

By R. S. Dean

[During the past fiscal year the Metallurgical Division has made important contributions along the lines dictated by the Bureau policy of conservation of domestic mineral resources through Its investigations include determining of fundamental data of metallurgically important materials improvement of standard ore-treatment method to eliminate waste and improve the grade or recovery of the products; and development o new metallurgical processes.]

Jan 1, 1940

By R. S. Dean

[During t!~c past f isc.~l y~:-.r the Xetzllvz-gicd 3ivi oion has made im- portant contribution-, don,- tlie lines rlictnteil by the Bureau policy of con- servation of domestic rnker~l rcsoul-ces throui;h use. During t!~c past f isc.~l y~:-.r the Xetzllvz-gicd 3ivi oion has made im- portant contribution-, don,- tlie lines rlictnteil by the Bureau policy of con- servation of domestic rnker~l rcsoul-ces throui;h use.]

Jan 1, 1940

By Peter G. Kovalchik, Rudy J. Matetic, Susan B. Bealko, Adam K. Smith

Overexposure to noise remains a widespread and serious health hazard in the U.S. service providing and goods producing industries. Excessive noise can lead to poor verbal communication and reduce the ability to recognize warning signals. These dangerous work conditions can also cause stress and fatigue. Occupational hearing loss is a permanent illness, with no recovery currently possible. Method: National Institute for Occupational Safety and Health (NIOSH) has recognized Noise Induced Hearing Loss (NIHL) as one of the ten leading work related diseases and injuries in the United States, and has emphasized its importance as one of the critical areas expressed in the National Occupational Research Agenda. Results: One of the most serious noise problems in the goods producing industries is the operation of continuous mining machines during underground coal mining. In order to minimize occupational hearing loss, noise hazards are “designed out” early in the design process. NIOSH is leading a national initiative called Prevention through Design (PTD) to promote this concept. This paper describes the quiet by design approach of a noise control that reduced noise exposures of continuous mining machine operators by 3dB(A) using the four functional areas of PTD, namely Practice, Policy, Research, and Education.

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 Henry C. Meeves

The nonpegmatitic sources of beryllium in Arizona, Colorado, New Mexico, Utah, and four adjacent states investigated by the Bureau of Mines are described. The investigations included 155 properties from which over 6,200 rock samples were collected; more than 5,500 samples were analyzed by the nuclear beryllium-detection technique. Twenty-four of the properties examined had rock containing more than 0.10 percent BeO. Many of the beryllium determinations were made in the field with portable detection instruments by direct scanning of outcrops and by testing samples of rock brought to the instrument. The large domestic resources of low-grade nonpegmatitic beryllium ore in Utah, which were discovered by private enterprise and which respond favorably to small-scale treatment processes, may come into commercial use and thus reduce the dependence of the United States on imported beryl.

Jan 1, 1966

By A. C. Burr

This progress report summarizes operating results on the gasification of natural lignite from five runs of the commercial-scale pilot plant at Grand Forks, N. Dak., during December 1946 and calendar years 1947 and 1948, when the plant was operated for 1,996 hours. A primary specific objective was to determine the useful life of the outer metal retort tube as it is influenced by corrosion and other factors under a wide range of operating conditions. A secondary objective was to develop the technology of production when generating gas with a high ratio of hydrogen to carbon monoxide in both the divided and continuous annuli. Results are summarized in graphs and tables that show hydrogen-carbon monoxide ratios from 2.3 to 9 at gas-production rates from 6 to 12 M cu. St. per hr. (thousand cubic feet per hour), or approximately 30 to 60 cu, ft. per square foot of heated retort-wall surface per hour. Gas yields ranged from 36 to 54 M cu, ft. per ton of natural lignite or 63 to 91 M cu. ft. per ton of moisture- and ash-free lignite, Production rates were higher in the divided annulus, but these represent the maximum capacity of the plant only at high hydrogen-carbon monoxide ratios when the high concentration of excess steam and low furnace temperature limit gas production. A ratio of 6 was the highest produced in the continuous annulus because mechanical Limitations of the auxiliary equipment prevented attainment of higher ratios. The lignite feed rate appears to influence the production rate more than any other individual operating variable. Heat balances for four periods when gas with ratios from 2.3 to 7.2 was produced with a lignite feed rate of about 325 pounds per hour suggest that the potential heat in the gas is lower at higher ratios, owing to increased heat losses in the excess steam. Heat-transfer rates through the retort tube in these four tests were between 1,500 and 3,000 B.t.u. per square foot per hour. These rates are much lower than those reached in many earlier tests, but no attempt was made to achieve maximum rates of heat transfer.

Jan 1, 1953

By J. E. Chilton

A technique for use in underground coal mines measures the response times of machine-mounted methane monitors. This technique uses a calibration cup to deliver gas to the sensor head to measure response times. For comparison, in the current study, response times were measured by placing methane sensor heads in a specially designed test box where they were exposed to an atmosphere containing a constant concentration of methane. Response time readings measured in the test box were shorter than the readings obtained using the calibration cup. The response times measured in the test box were comparable for sensors from three different manufacturers. The effects of dust cap and flame arrestor design on response times were also evaluated using the test box.

By Homer J. Ballinger

The Krueger property was examined by an engineer of the Bureau of Mines in September 1943. The records of 23 old drill holes indicated an appreciable body of ore without delimiting the deposit. It appeared that additional drilling might increase this reserve sufficiently to justify mining. Accordingly, the Bureau of Mines drilled 5 churn-drill holes and 19 diamond-drill holes on the Krueger tract. The last of these holes concluding the Bureau?s project was completed in April 1947.

Jan 1, 1948

By James A. Wasson, Harry R. Johnson, Dean W. Boley

The Cow Run sand was cored and electrical and radioactivity surveys were made in C. E. Vandevender well 35 in the Burning Springs pool of the Burning Springs oilfield , Wirt County , W. Va . Laboratory tests , reservoir - fluid analysis , well - log interpretation , and available field data indicate that a substantial quantity of oil may be recovered from this pressure - depleted reservoir by waterflooding . Two formations erroneously believed to be the First and Second Cow Run sands were similarly evaluated in A. E. Mackintosh well 8 , Anns Run Pool , Wirt County , W. Va . , but were found unsuitable for secondary - recovery operations .

Jan 1, 1964

By Charles T. Holland

ANALYSIS of 117 occurrences of bumps in coal mines shows that 67.6 percent are associated with pillar-line points.4 Slabbing and splitting pillars, development, and other unfavorable milling practices in abutment areas may be a contributory or the primary cause of bumps. The cure for pillar-line bumps is to recognize areas that can be expected to become highly stressed and to project the mining plan and operations to eliminate such areas insofar as possible. If such areas cannot be eliminated, then the mining plan and operations should be projected to avoid the necessity of disturbing these areas before the stresses have been dissipated.

Jan 1, 1954

By R. E. Mussier

This investigation was made to study new methods to prepare high-purity yttrium metal, Various methods were used to prepare pure intermediate compounds, primarily chlorides, bromides, and iodides, which were subsequently reduced to metal. The process found most suitable for the preparation of pure anhydrous yttrium chloride involved thermal dehydration of a mixture of hydrated yttrium chloride and ammonium chloride while under vacuum. Yttrium bromide and iodide were prepared most effectively by the direct halogenation of yttrim carbide. Yttrim carbide was obtained by reacting and melting yttrium oxide-carbon mixtures in a carbon-arc furnace. Yttrium halides were purified by vacuum distillation and reduced by alkali or alkaline-earth metals. Lithium and sodium proved to be the best reductants from the standpoint of yield (>95 pct) and purity (>99.8 pct) of the yttrium. The product of the reduction step was sponge metal, which was consolidated readily by conventional cold-mold, arc-melting procedure. The purest yttrium obtained in laboratory scale work was prepared by sodium reduction of yttrium chloride and contained only 125 pp oxygen; other impurities did not exceed 1,000 ppm. In larger scale tests yttrium containing only 800 to 1,000 ppm total impurities was obtained by lithium reduction of yttrium chloride. The tensile properties of high-purity yttrium were determined. Mechanical tests showed that yttrium can be forged, extruded, rolled, spot welded, and deep drawn.

Jan 1, 1963

By WILLARD W. CUTLER

This bulletin reviews, in the light of recent experience, the use of production-decline curves in estimating the future production of oil from wells. It deals with the estimation of the reserves of recoverable oil in properties already producing or in those adjacent to them, takes cognizance of the physical laws governing expulsion of oil from oil sands, and shows how the production-decline curve can be made to utilize these laws in estimating reserves and rates of production. The valuation of oil properties should be based on the total amount of oil recoverable from a property by the methods in use, the rate of recovery, the cost of production, and the selling price. Numerous other curves besides those for reserves and rates of production may be formed from the production-decline curve and will present desired information in a convenient time-saving form. These curves also are described. Methods developed before the production-decline curve method was used are briefly discussed in order that the principles on which estimations of oil reserves are based may be made plain. The construction of curves and tables for estimating future production of individual wells and of average wells in most of the important oil districts of the United States is described and operating problems that may be solved by the use of production-decline curves are discussed. The bulletin does not deal with costs, oil prices, or the methods of evaluating oil properties. Many engineers have amply demonstrated the value of the production- decline curve method by forecasting within reasonable limits the production of many thousands of wells and tracts. The value of similar estimates depends however, on (1) the application of trustworthy methods; (2) the care and judgment of the estimator; and (3) the length and reliability of the records and the accuracy of ofher information used in estimating future production. When adequate records and information are available, experience has shown that It qualified engineer can forecast production far more accurately than has been deemed possible, except where the usual conditions governing the expulsion of oil from a sand have been radically changed by applying compressed air or by flooding with water, or, to a less degree, by using vacuum. In general, the production-decline curve method, though there are limits to its accuracy, is far more trustworthy than any other.

Jan 1, 1924

By J. R. Thoenen, J. D. Warne

"INTRODUCTION Red-iron-ore deposits in northeast Alabama have been exploited at vari¬ous times for nearly 6o years. About 3-1/2 million tons of ore have been produced in the Gadsden district; but mining activity has been dormant since 1926, and furnaces within this section of the State now suffer a shortage of red ore.To alleviate these shortages, work by-the Bureau of Mines was recommended after preliminary investigations. 4/5/ Diamond drilling, to determine the lateral and vertical extent of ores of known deposits in Greasy Cove and on Shinbone Ridge, was done from August 1946 to May 1947, as Project 9-106, Alabama Red Iron Ore. Three holes were drilled in each area.ASKNOWLEDGMENTSIn its program of investigation of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of domestic mineral resources to the end that they- make the greatest possible contributions to the national security and economy. It is the policy of the Bureau to publish the facts developed by each project as soon as possible after its conclusion. The Mining Division, Lowell B. Moon, conducts preliminary examinations, does the actual investigative work, and prepares the final report. The Metallurgical Division, Oliver C. Ralston, chief, analyzes samples and makes beneficiation tests."

Jun 1, 1948

By Charles L. Kimbell

The year 1986 was not a good year for the world's mineral industry from several viewpoints. Levels of production, both of crude minerals and processed forms, registered declines in the cases of a greater number of commodities than the number that recorded increases. The overall value of world crude mineral production was estimated to have increased, but only very slightly in terms of constant dollars to nearly $997 billion. Although there were modest increases in the consumption of all major fuels and most major metals, the latter at least apparently resulted more from drawdowns of inventories than from increased production (fuel consumption increases did come from higher output levels), and consumption of most major fertilizer and chemical commodities (nitrogen, phosphate, and sulfur) were at lower levels than those in 1985. Prices for a number of mineral commodities declined, headed by the very substantial drop in world crude petroleum prices, but also including downturns for a number of metals and industrial minerals as well. There was insufficient information to reliably fix the level of the dollar value of world trade in minerals, for while output was up in the case of some large-volume materials such as iron ore, coal, and crude and refined petroleum, suggesting that the volume of trade in physical units may have increased, declining prices may well have offset quantitative gains.

Jan 1, 1988