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By John F. Wiss

A series of controlled experiments was conducted at four surface coal mines to study the effects of certain blast parameters upon the ground and air vibration. Preliminary scale-model blasts were conducted at a quarry to provide basic data. It was found that the amplitudes of the ground and air vibration were controlled by the maximum explosive weight per delay. Either cube root or square root scaling could be used for the seismic amplitudes, and cube root scaling could be used for the overpressure amplitudes. Both amplitudes were not significantly affected by the total charge weight per blast, the attitude of the boreholes, or the charge length or diameter. The overpressure amplitudes were affected by the charge depth, the use of cover over surface detonating cord, and the use of adequate stemming. The length of the delay intervals and the spacing of holes were important in determining' the potential fur reinforcement of the amplitudes in certain directions from the blasts. In downwind directions from the blast, the attenuation of the overpressure with distance decreases. Surface terrain did not significantly affect the overpressure amplitudes within the range investigated. The type of overburden affects the generation of both amplitudes and the propagation of the seismic amplitudes. Spectral analysis of the ground and air vibration is reported. A bibliography of pertinent literature is included as an appendix. A scaled distance of 300 ft/lb1/3 should produce a peak particle velocity of less than 1 ips and an overpressure of less than 128 dB linear peak. For square root scaling, a scaled distance of 75 ft/lbl/2 should limit the ground vibration to less than 1 ips.

Jan 1, 1978

By Mark K. Larson

Researchers at the U.S. Bureau of Mines have developed a FORTRAN computer program that can calculate stress states from overcoring measurements obtained from hollow inclusion cells, triaxial cells, strain gauges installed on the wall of a bored raise, doorstopper gauges, borehole deformation gauges, or a combination of any of these gauges. Such stress states are calculated with reference to global and principal coordinate systems. The background of the development of the program, its capabilities, and its special features, as well as the input required, are described in this report. Sample output is also shown in appendix C. Difficulties associated with numerical calculations of principal stresses and directions are pointed out. Threshold values for detecting these problems are reported; these values may be changed by the user as desired. Several test problems were set up to verify the computer program and were successfully solved.

Jan 1, 1992

By Walter R. Storms

"INTRODUCTION The New Mexico potash exploration described herein was begun in February 1944 with the object of determining the amount of potash ore in the United States Potash Reserve in Eddy County by exploring the deposit from the surface with vertical drill holes. The work was completed in October of the same year after 16 holes had been drilled on the Reserve and in the immediate vicinity.The Potash Reserve is in secs. 26; 27, 34, and 35, T. 20 S., R. 29 E., Eddy County, N. Mex., about 14 miles northeast of Carlsbad, as shown on figures 1 and 1A, Drilling was done in secs. 26 and 35 of the Reserve, in section 14 to the north, end sections 2 and 56 to the east. All work was done on Governnent-owned, unleased land.The Reserve may be reached from Carlsbad by traveling to the north-east by automobile for about 14 miles on the paved U. S. highway 62. This highway passes through the southern part of the Reserve. Other parts may be reached by a State highway that passes along the eastern side of the area, then by poor dirt roads to various drilling sites. A branch of the Santa Fe Railroad also passes across the southern part of the Reserve enroute from Carlsbad to the plant and mine of the Potash Co. of America, a few miles northeast of the project and 22 miles from Carlsbad."

Aug 1, 1947

By K. E. Stanfield

[Asphalt ~~d road oil ar8 the principal products manufactured from Wyor.1in~ Ilblack oilo" \r,hich, beca.use of th?lir hig.~ E\.sphal t and hig} sulfur COi.1Jce~1t, .!?re difficult e':ld costly to refine into hi?;h-gra.de motor f 101s, burning oils. and lucri ants by presont mothods. Accordin~ly. the demand for truHle asphaltic renidl urn for the construction of roade aJ1.d other uses is 3. controlling factor in the quantity of crud~ oil prod ICed. The increasiilg -u.tilization of special aST>ha.lts as ine}""Pensive bonding, in-]

Jan 1, 1941

By H. B. Jensen

STUDY of the thermal-solution process was begun by treating crushed oil shale in a small autoclave at temperatures of 700° to 950° F. The effect of temperature, reaction time, type of solvent, and richness of shale upon the amount of organic matter that was removed from the oil shale was thus determined. Following this orientation work a semicontinuous, bench-scale apparatus was built so that heated solvent could be pumped through a bed of shale under elevated pressure, thus removing the converted organic matter from the spent shale. After some operating experience had been gained, a continuous unit was constructed. This permitted treating a slurry of shale oil and pulverized oil shale at about 300 p. s. i. and temperatures of 750° to 850° F. for various retention times. Considerable cracking and polymerization of the shale oil were found to take place during the process. In an attempt to prevent this, a study was made of extraction of the shale in batch-type autoclaves under high partial pressures of hydrogen at total gas pressures of as much as 4,300 p. s. i. at 850° F. The thermal-solution process was found to convert over 90 percent of the organic matter in oil shale to oil and gas. The highest yields of gas and oil obtained without hydrogen pressure were equivalent to 119 weight-percent of those obtained from the same shale by Fischer assay. With a high partial pressure of hydrogen, yields equivalent to 126 weight-percent of Fischer assay were obtained. However, the oil produced by thermal solution has a higher boiling range than that obtained by other retorting methods, particularly so if the thermal-solution process is used without a high partial pressure of hydrogen. Nondistillable oil (all benzene-soluble material that would not distill under 2 mm. Hg absolute pressure without cracking) equivalent to over 100 percent of the organic matter in the shale was obtained without hydrogen pressure in the system. When the process was carried out under hydrogen pressure, the yield of nondistillable oil amounted to 60 to 70 weight-percent of the organic matter. Part of this heavy material is formed partly by polymerization and condensation of the shale-oil solvent used. These reactions, as well as cracking of the solvent to form gas and a carbonaceous deposit on the shale, are unfavorable features of the process.

Jan 1, 1953

By John C. Machisak

INJURY experience and employment data for the nonmetal mining industry in the United States are presented for the calendar year 1958. Statistical tables 6 to 12 give detailed information on injuries and employment at nonmetal mines. Data for nonmetal mines are presented separately from those for nonmetal mills, tables 23 29. The Bureau is authorized to send questionnaires to the nonmetal industry for their voluntary submission on of injury and employment experience at their operations. As this information contributes to the promotion of safety in the nonmetal mining industry, every effort has been made to make these questionnaires as complete as possible.

Jan 1, 1962

By Mackenzie Burnett

An inducer-type pump, capable of injecting dry coal into a hydraulic transport pipeline has been developed and installed in a specially designed and fabricated slurry injector vehicle. The full scale prototype injector system can deliver up to 11 ton/min of coal into an 8-in pipeline t pressures up to 95 lb/in2. The Helical Inducer Injector operates on centrifugal principles with flow passing axially through helical pitched conical rotor. Water is delivered to the pump through an annular slot at the atmospheric pressure coal inlet. The spinning rotor maintains an air-core vortex of water which pressurizes the discharge housing. A screw feeds coal through the open inlet into this vortex. The inner radius of the vortex contracts as pressure is increased, giving a limiting maximum pressure which is proportional to the square of the rotor speed. Below this limit, flow rate, discharge pressure, und rotor speed re independent variables. The self-powered, 4 -in high slurry injector vehicle follows and receives ROM coal from a continuous miner, reduces the top size to 3-in, and delivers the sized coal to the injector feed screw for slurry formation and pumps it through a mobile hose attached to the vehicle's outby end.

Jan 1, 1983

By Jack Wright

The analysis of water produced with crude petroleum has interested oil producers since inception of the industry. Records of the first analysis of mineralized water produced from an oil-productive formation are obscure, and references to the first use of brine analyses to assist in solving problems of petroleum production are not available in the technical literature. However, many early reports of the Federal Bureau of Mines5-8 and Federal Geological Survey,9-11/ as well as articles in engineer and geological journals12-14/ placed special emphasis on the importance, interpretation, and application of water analyses. One of the earliest applications of water analyses, and still a major one today, is for identification of intrusive waters in oil wells. This may be done by comparing the chemical constituents of a sample of water indigenous to the oil-productive formation with those of samples from upper, water-bearing formations within the same general area. Some earlier investigators recognized the need for Analyzing samples of all waters encountered in drilling operations. Ambrose15/ stated, in part, "In wells being drilled, the engineer should grasp every opportunity to get a true sample of water from each sand. . .," and, "The waters of each oil field are chemically different from those of another field." The validity of the latter observation and the importance of the former one have been borne out by comparing the results of analyses of many samples and noting the differences in relative concentrations of like constituents of waters from the a geological formation in different localities or oil pools.

Jan 1, 1957

By W. L. Heidenreich

This report describes the methods and results of field investigations conducted by the Bureau of Mines between December 1956 and December 1957 on seven deposits of nickel-cobalt-iron-bearing laterite and weathered serpentine near the west coast of Puerto Rico east and south of Mayaguez. These deposits were named, for purposes of identification, Guanajibo, Punta Guanajibo, Las Mesas, north and south deposits of the Rosario Southeast group, and the west and east deposits of the Maricao Southwest group. In addition, the lower 17 miles of the Guanajibo River Valley was tested at widely spaced intervals for possible concentrations of magnetite and chromite in the alluvial sands. The objective of the investigations was to appraise, by drilling and sampling, the two largest deposits--the Guanajibo and Las Mesas. Testing of the smaller deposits was much more restricted. Field investigations consisted of mapping, drilling with power auger, sampling drill-hole sections, and pre-paring samples for chemical analyses, mineralogical studies, and metallurgical tests. The work was financed jointly under a cooperative agreement by the Bureau of Mines and the Economic Development Administration, an agency of the Puerto Rican Commonwealth.

Jan 1, 1959

By Jr. Hardy, H. Warren Shen

"A study is presently underway by the authors to investigate the character of the bit-coal interaction during coal cutting and its influence on the size and shape distributions of the generated dust. An important aspect of this on-going project is the development of acoustic emission (AE) criteria which would make it possible to carry out remote monitoring of coal cutting operations. The on-going AE studies are fundamental in form and were undertaken to evaluate the general feasibility of AE monitoring techniques using simplified coal breakage and cutting procedures. The present paper will focus on the test facilities, experimental techniques, and results associated with linear, single-bit cutting. An AE-transducer, attached directly to the bit, detected AE signals during the cutting process.Experiments have been carried out on seven specimens of coal obtained from the USBM experimental mine at Bruceton, Pennsylvania. Three separate cuts were made for each of two bit angles (10 and 45 degrees) and two bit velocities (0.085 and 0.169 cm/sec), for a total of 12 separate cuts. Data associated with resulting particle size distribution and AE characteristics (major dominant frequency components) will be discussed. Data analysis has also been underway using a computer-based pattern recognition system known as ICEPAK (Intelligent Classifier Engineering Package). This program is able to evaluate over 100 features of an AE event and to make objective comparisons between AE signals associated with different loading or cutting parameters. The results to date show that AE generated during some of the test conditions can be recognized by ICEPAK with a recognition rate of 90% and higher while other conditions cannot at present be separated with a suitable recognition rate. Further analysis of the experimental data is presently underway.The reduction of the severity, and eventual elimination, of Coal Workers' Pneumoconiosis (CWP) depends on gaining fundamental understanding in a number of major areas. These include dust generation and entrainment, transportation, suppression, medical effects of dust, and possible treatment. At present a project is underway by the authors to investigate the character of the bit-coal interaction during coal cutting and its influence on the size and shape distributions of the generated dust. An important aspect of this on-going project is the development of acoustic emission (AE) criteria which would make it possible to carry out remote monitoring of coal cutting operations. Suitable on-line analysis of monitored AE data would allow engineers to evaluate factors such as shearer bit conditions and cutting efficiency, and to quantify the particle size and shape distribution of the generateddust. The on-going AE studies are fundamental in form and were undertaken to evaluate the general feasibility of AE monitoring techniques using simplified coal cutting procedures. To date experiments have been carried out on coal under uniaxial compression, linear single-bit cutting, and cutting using a laboratory-scale, single-bit shearer. A brief outline of the overall study has been presented in an earlier paper (Hardy, Shen and Kimble, 1995). This paper will consider the linear single-bit cutting studies in more detail.It is generally accepted today that most solids emit low-level seismic signals when they are stressed or deformed. In this paper this phenomenon will be referred to as acoustic emission (Hardy 1972, 1981, 1989). In essence, the measurement of AE activity in a field or laboratory structure is relatively simple. A suitable transducer is attached to the structure, the output of the transducer is connected to an associated monitoring system, and the AE signals occurring in the structure, due to internal or external stress, deformation, and failure are suitably acquired, pre¬processed and recorded."

Jan 1, 1998

By Forrest T. Moyer

Injury experience in the coal-mining industry was worse in 1965 as both the frequency and severity rates of injuries increased 2 and 6 percent, respectively, over comparable data for 1966 (tables 1-8). The retrogression in the safety record during; 1965 resulted frog the less favorable record at bituminous-coal mines, which more than offset the improved injury experience at anthracite mines. The 259 fatal and 11,138 nonfatal injuries occurred at a rate of 45.77 per million man-hours of exposure and resulted in a severity rate of 8,960 days lost per million man-hours. Although the number of fatalities was the second lowest annual total in the recorded history, it was 17 higher than in 1964. At anthracite operations the total of 6 fatalities in 1965 was the lowest annual figure in statistical history. The annual numbers of nonfatal injuries at ill coal mines and the resulting rates of occurrence have varied little in the past 5 years (table 1). The total days lost from all injuries rose from 2.1.3 million in 19b4 to 2.23 million in 1965 (table 5). Fatal and permanent total injuries, with a standard time charge of 6,000 days each, accounted for 1,650,000 days; Permanent partial injuries, 191,932 clays; and temporary total disabilities, 383,911 days. The severity rate for fatal injuries was 6,241, 8 percent higher than in 1964, and the nonfatal severity rate of 2,718 days lost per million man-hours was 2 percent higher than in the preceding year. The average severity of permanent partial injuries ire; 730, or 48 days fewer per injury than in 1964. The average days lost for each temporary total injury was 36 days in each year.

Jan 1, 1968

By Dale R. Spangenberg

This Bureau of Mines Information Circular on phosphate is one of a series of minerals availability commodity directories. Nonconfidential information from the Minerals Availability Program data base covering 148 domestic and 103 foreign phosphate properties and deposits has been abstracted for use in this directory. Abstracts include applicable data on location, published reserves and resources, geology, mine and beneficiation systems, and operational information.

Jan 1, 1983

By R. M. Strong, Lauson Stone

Under the terms of the act establishing the Bureau of Mines, this bureau was authorized to carryon the work of testing and analyzing fuels which had been conducted by the technologic branch of the United States Geological Survey. That work included in its scope an investigation of the availability and uses ofliquid as well as solid fuels, for the original outline of the fuel-testing investigations contemplated, as soon as the funds would be available, a study of the liquid-fuel resources of the country and the making of related researches to determine how these resources could be utilized with greatest efficiency. Owing to the fact that many difficulties were being encountered in the adaptation of the heavier fuel oils for convenient use in internalcombustion engines, it was deemed best to begin the investigation of liquid fuels with tests of gasoline, a fuel in more or less general use. When this investigation began, the extensive introduction, especially by foreign powers, of liquid fuels for small naval craft had awakened much interest. However, the quality of gasoline was reported to vary materially in different countries and the quantity available was said to be rapidly decreasing, with the probability of a prohibitive increase in price. At the same time the claim was made that denatured alcohol, of fairly uniform quality, could be procured in all parts of the world, that unlimited quantities could be readily produced at a low cost, and that this fuel could be used much more efficiently than gasoline in internal-combustion engines. Such statements naturally led to a widespread belief that the time was near at hand when denatured alcohol would entirely displace gasoline as engine fuel. Therefore, the first investigations of the liquid mineral fuels logically embraced a careful series of comparative tests of gasoline and denatured alcohol in engines. A series of over 2,000 such tests was conducted at the Government fuel-testing plants at St. Louis, Mo., and Norfolk, Va., details of which are given in the following pages. The report is published by the Bureau of Mines because of the transfer of the fuel-testing investigations to this bureau.

Jan 1, 1912

By J. A. Kosek

Work has been carried out under Bureau of Mines Contract HO 395132 to develop improved sensor cells for use in direct-reading detectors and diffusion exposure meters. A pumped CO sensor cell was developed which has a shorter response time, improved temperature cycle characteristics, and improved linearity and stability at high CO concentrations. Diffusion CO sensor cells have shown good response level stability and linearity up to 1000 ppm. In addition, a new sensor cell catalyst has been developed for NO2 sensor cells which has a much shorter response time and improved response stability characteristics.

Jan 1, 1982

By Frank C. Townsend

Waste disposal schemes using spent shale in embankments require a thorough knowledge of its geotechnical engineering properties for environ-mentally safe disposal. In this context, the objective of this laboratory investigation was to determine the physical properties, geotechnical properties, and composition of spent oil shale retorted by the PARAHO and TOSCO processes. Physical properties consisted of mechanical analyses, Atterberg limits, and specific gravity determinations. Geotechnical engineering properties were determined by compaction, maximum-minimum density, unconfined compression, triaxial compression, permeability, direct shear, Ko, cyclic tri-axial, resonant column, and Los Angeles Abrasion tests. Petrographic, chemical, and scanning electron microscopy analyses were used to determine compositional features. Unprocessed shale is hard and durable and more properly described as a carbonate rock instead of shale. PARAHO is classified as a GP, while TOSCO classifies as an SM. PARAHO requires no moisture for compaction to maximum densities; however, TOSCO does. Retorting causes a loss in durability but creates self-cementing characteristics, which for PARAHO a 3-to 8-fold strength increase was observed, while for TOSCO the increase was 1.5 to 3 folds. The shear strength, compressibility, and dynamic properties of compacted PARAHO are comparable to those for sandy gravels. Compacted PARAHO is semipervious, while compacted TOSCO can be semipervious to impermeable.

Jan 1, 1979

By Paul L. Michael

This report presents a discussion of perforance parameters for electronic or active hearing protectors that will meet the needs of underground coal miners. This information is incorporated into a proposed set of specifications that can be used to judge the suitability of a particular electronic hearing protector for the coal mine application. Acoustic and electrical tests were performed on a developmental model of an electronic hearing protector built by the U. S. Bureau of Mines. This model showed only a slight reduction in speech intelligibility which was traced to poorly matched components and in particular to the transducers. Tests of alternative components showed the Knowles BL-1671 microphone to be suitable for this application because of its performance and extremely small size. The Roan-well H-143/AIC earphone was found to have a good frequency response but has the disadvantage of being rather bulky which causes a slight degradation of a low frequency attenuation of the hearing protector. A satisfactory installation of these components in a hearing protector muff was demonstrated and tested. Results of tests of several methods of controlling the sound level under the hearing protector muff showed that a simple diode clipper circuit can be used with only a negligible loss in speech intelligibility for normal-hearing listeners. A commercially available active hearing protector, the British-built ACOS A-9000/2 was examined. This hearing protector provides sound level limiting through a saturating amplifier. Preliminary tests have shown that the performance characteristics of this commercial unit meet many of the proposed specifications so further testing and evaluation should be performed to determine its suitability for use 1n underground coal mines. The recommended test of intelligibility for electronic hearing protectors and other communication systems as used in a coal mine setting is the Modified Rhyme Test (MRT) developed by House et al. in 1965. The suitability and method of administering this test are discussed.

Jan 1, 1976

By Larry A. Lass

The U.S. Bureau of Mines, in cooperation with the Iron Range Resources and Rehabilitation Board, investigated the potential of using northeastern Minnesota papermill waste sludges as a binder for Mesabi Range iron ore (taconite) concentrate. Sludges from five different commercial papermill waste treatment operations were evaluated in laboratory tests. Except for the coarsest sludge, all were fairly easy to blend with the taconite concentrate using conventional mixing methods. The coarsest sludge had to be reslurried at 2 pct solids before adding it to the concentrate in order to obtain pellets without visible sludge clumps. Drying and grinding the sludges made them less effective as binders because of a lower degree of rehydration. On a dry weight equivalent basis, twice as much raw sludge binder was required to obtain similar pellet physical properties as with bentonite; however, the pellets made with raw sludge had superior metallurgical properties. Over 30 pct higher reduction rates and over 1500 C higher softening temperatures were obtained with sludge binder than with bentonite. Sludge D, which had the lowest fiber and the highest alkali metal content, resulted in the lowest reducibility enhancement. Even though more raw sludge was required than bentonite, the sludges have virtually no value, and therefore may provide a cost-effective additive binder for producing improved metallurgical-quality pellets. Large-scale testing has not been done to confirm these laboratory results.

Jan 1, 1989

By W. S. Landers

This report presents a study by the Federal Bureau of Mines of technical factors related to the production of special carbon and tar from selected Wyoming coals. Certain Wyoming high-volatile bituminous and subbituminous coals were processed in bench-scale apparatus to determine potential carbonization yields and in pilot plant retorts to produce sufficient char and tar for testing. These tests have shown that a critical selection of coal is necessary when the coal is processed for a specialized carbon. Generally high yields of tar are obtained from low-temperature carbonization of Wyoming high-volatile bituminous and subbituminous coals, and the yield of tar usually increases with increase in rank within this range of coals. The production and evaluation of industrial carbons from Wyoming coals by using pilot plant and bench-scale techniques is part of the continuous program of upgrading western coals. It has been found that: 1. Most Wyoming coals are nonagglomerating and may be carbonized in fluidized systems. Chars produced in pilot plant retorts at low temperatures contain about 17 to 23 pct, residual volatile matter and are easily ignited. These chars appear suitable as power plant fuel. The tar-plus-light-oil yields range from 14 to 40 gal./ton of raw coal processed. 2. Wyoming high-volatile coals produce a slightly smaller and somewhat weaker coke than currently mined Western United States high-volatile coals used commercially as blending stock in metallurgical coke production.

Jan 1, 1961

By Ross. C. Barkley

A computer program has been written to simulate ground vibrations induced by multiple-hole surface blasts. The program is an inexpensive and relatively easy to use tool for predicting the principal blast vibration characteristics that determine damage and annoyance potential: peak particle velocity, frequency content and pulse duration. The program generates a complete ground motion history by superposing, at any surface position, the vibrations induced by each individual explosives charge. It requires specification of (hence allows accounting for) the blast geometry, initiation sequence (including random delays), position with respect to blast, pulse characteristics induced by each charge, and propagation laws. A methodology is outlined to determine the necessary variables either on the basis of site investigations (e.g. velocity, attenuation, pulse), or by backcalculation from measured blast vibration records. The latter procedure has been applied to blasts from two coal strip mines. Main difficulties are backcalculating individual pulses, propagation (especially dispersion) parameters and delays. A normal distribution of delays, based on published results, has been shown to influence the results and the response of a single degree of freedom structure significantly. Broadening of the wave types included and additional verifications with field results are required.

Jan 1, 1983

By Kenneth Maas

The Bureau of Mines devoted portions of the 1987-1988 field seasons to investigate the mineral aggregate industry in Juneau, Skagway, Haines, and Gustavus, Alaska, as part of the Juneau Mining District study. Statistics compiled for current suppliers include location, activity, reserve estimates, expected mine life, and types of commodities available. Each population center, except for Gustavus, is well endowed with suitable mineral aggregate to last at least 20 years. The Bureau of Mines quantified the mineral aggregate resource in many large potential sites within each area. Sampling, engineering and soil-index testing, site descriptions, deposit dimensions, and gold recovery information is described. Refraction seismic studies performed at three localities revealed gravel thicknesses in excess of 40 to 80 feet. In the Juneau area the Herbert/Eagle Rivers outwash area, East Fork Lace River. Antler/Gilkey Rivers, and Grizzly Bar (Taku Inlet) individually contain in excess of 60 million yd3 of excellent-quality aggregate with minor accessory gold credits. Haines is also well endowed with aggregate resources; large, quality deposits occur along and at the confluences of the Chilkat, Katzehin, Klehini, Tsirku, and Kicking Horse Rivers. Large deposits of granitic aggregate exist in the Skagway River and East Fork Skagway River.

Jan 1, 2012