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By R. W. Freedman

The gas chromatographic method, devised by the Bureau of Mines for analyzing routine mine air samples, was compared with the infrared method used for confirmatory determination of methane in mine air. While maintaining the specificity of the infrared method for methane determination, the gas chromatographic method is more precise, much more rapidly performed, and more convenient.

Jan 1, 1968

By James Rowland

On June 1, 2004, the underground coal mine ventilation safety standards under the Code of Federal Regulations (Title 30, Part 75) became effective for the use of a conveyor belt entry as an intake air course to ventilate working sections. These standards, also known as the Belt Air Rule, contained a section which limited the air velocity in the conveyor belt entry to no greater than 500 feet per minute unless otherwise approved by the US Mine Safety and Health Administration in the fire suppression system section of a mine?s ventilation plan. The Belt Air Rule included a requirement dictating compatibility of air velocity with fire suppression systems. The final rule of limiting air velocity in the belt entry was challenged in the Court of Appeals for the District of Columbia Circuit. The court granted that petition and vacated the requirement on the air velocity cap, according to MSHA. The removal of the air velocity cap from the final rule, paired with the compatibility requirement, led to a need for research on high air velocity?s influence on fire suppression system performance in belt entries. Test data was needed that illustrated the relationship between fire suppression system performance and air velocity, especially with the increased use of wider belts in underground coal mines, so National Institute for Occupational Safety and Health and MSHA collaborated to obtain the data. However, this work was initiated before the revised Belt Air Rule was promulgated on December 31, 2008, when 1000 fpm air velocity became a requirement. Four different

Jan 1, 2009

By Raymond B. Ladoo

"The recent discovery and exploitation of petroleum territory have resulted in the enactment of new petroleum laws in most of the South American Republics. The activities in the discovery of these new fields were engendered by the knowledge of the fact that present producing fields must within well defined periods be exhausted. Oil operators were willing to take the initial steps in exploitation in the absence of legislation that applied strictly to petroleum operations. The enactment of modern legislation in many of these Republics encouraging and protect¬ing exploitations may cause tremendous oil activities in these countries, and the results may be comparable with the magnitude of the undertakings and the prestige of the companies now entering this territory.These, oil fields are admirably located for convenient distribution of petroleum by water to all the Nations using oil as fuel for shipping and industrial concerns. The oil markets of the western coast of South America will derive immense benefits from the Panama Canal. This navigation route brings these markets into direct ocean shipment with the Atlantic coasts of the Western and Eastern Hemispheres.One deterrent to oil production in the Republics of South America is the want of inland. transportation facilities, but the recent laws of these Republics without exception provide for acquiring rights of way for pipe lines and other modes of transportation; and doubtless the great interests and. syndicates already operating in these regions will, as production increases, provide ample pipe line transportation sufficient to convey to the coast the oil produced. It way be assumed, from the legal guarantees afforded, and from operating equipment and machinery that are now being concentrated that refineries will be erected at shipping points for the purpose of making these petroleum products accessible to the world."

May 1, 1921

By Kenneth L. Rubow, Virgil A. Marple, Zhigun Zhang

"A theoretical technique has been developed and verified experimentally for determining the aerodynamic diameter of irregular shaped particles. The aerodynamic diameter of a particle is a very important parameter for determining where that particle deposits in the respiratory tract. Many instruments, such as impactors and cyclones, will determine the aerodynamic size distributions of aerosol particles but few analyze the particles individually. The theoretical approach of our technique is to solve, by use of high speed computers, the three-dimensional Navier-Stokes equations to obtain the flow field around an irregular shaped particle of any contour. The computer program will then determine the drag on the particle, and thus the aerodynamic diameter of the particle can be calculated. The experimental approach has been to pass the particles through a centrifuge and collect the particles upon a collection foil. The position of a particle on the foil is an indication of its aerodynamic diameter. These particles were then shadowed in two orthogonal directions and inspected under an scanning electron microscope (SEM). The top view of the particle in the SEM plus the views of the two orthogonal shadows allows one to determine the three-dimensional shape of the particle. Studies have been performed on silica, coal and talc particles with aerodynamic diameters in the 1 to 4 µm size range. The three-dimensional shape, as is determined from SEM analysis, was used in the theoretical computer program and the results compared. It was found that in most cases the agreement between the experimentally and theoretically determined aerodynamic diameters was within 5%. INTRODCJCTIONThe equivalent aerodynamic diameter (EAD) of a particle, defined as the diameter of a unit density sphere with the same falling speed as the particle in question, is an important size measurement of the particle. This is especially true when attempting to predict where particles may deposit in the respirator tract. Therefore, EAD is an important parameter when considering respiratory diseases caused by particles, such as coal workers pneumoconiosis (CWP).Many instruments will measure the EAD size distribution of the aerosol particles, but few analyze the particles individually. Impactors, cyclones and virtual impactors normally collect particles upon substrates or filters which are · then analyzed gravimetrically to determine the mass concentration of the particles in that size classification. The EAD of particles can be measured on an individual basis with centrifuges, inertial spectrometers and the TSI Aerodynamic Particle Sizer (APS). Centrifuges are most ideally applicable for studying individual particles as the particles are deposited, on long removable foils, at locations dependent upon their EAD."

Jan 1, 1990

By M. M. Myers

"Importance pf the small stone problem.Profitable disposal of limestone too small for making lime in the shaft kiln, is one of the most urgent problems in the lime industry. Reports received by the Bureau of Mines from 31 quarries show that the proportion of small stone varies from 2 to 40 per cent, averaging 18 per cent of gross pro¬duction, Modern methods of heavy blasting, and the use of crushers in large quarries tend to increase the proportion of small stone above that produced in early days when light blasting and hand sledging were almost universally used. There is also a growing movement toward underground operation of lime deposits, a method which in general produces a greater proportion of fines than is encountered in open-pit work. Thus the small stone problem is of growing importance, and demands the attention of every progressive lime producer. As the problem is of almost universal interest, it is urgently desired that every operator who reads this report will contribute from his knowledge or experience, answers to the questions on the final sheet.There are several markets in which small stone may be sold but in these markets the competition is generally keen and the prices low. The lime producer's chief product is lime, he understands its manufacture and marketing, and brings him a greater return than can be obtained from most limestone by-products. For these reasons it is evident that the conversion of small into lime is the nest desirable means of disposal."

Apr 1, 1924

By John E. Pahlman

An increasing number of gold and silver mining operations are employing cyanide solutions to effectively dissolve silver and gold from finely disseminated ores. Many of these operations use small, packaged processing systems like the State of Maine filter system, which employs zinc precipitation of gold and silver. Solution-clarifying filters in these systems become blinded with calcium carbonate (CaC03) scale and require frequent (every 2 to 10 days) dismantling of the filter units for acid cleaning, This is a hazardous operation as it is not compatible with the alkaline cyanide leach solutions and may result in the evolution of toxic hydrogen cyanide (HCN) gas during cleaning and during any accidental acid spill. The Bureau of Nines has investigated an alternative, nonacidic method of cleaning blinded State of Maine filters that employs ethylene- diamine-tetraacetic-acid (EDTA) type chelating agents to dissolve the scale. In situ cleaning of a 150-st/d State of Maine filters with EDTA- type chelating agents was successfully demonstrated. Greater than 90 pct of the CaC03 scale was removed in about 10 min with circulation of 31 L of 2.5-pct-EDTA solution through the filter unit. The EDTA cleaning method not only eliminates the cyanide hazard in filter cleaning but is advantageous from the standpoint of operating costs and productivity.

Jan 1, 1986

By Thomas V. Falkie, R. Venkataramani

1. Summary This investigation is concerned with description of the loading function at the underground coal face, and the identification of varia¬bles - geological, geometric, mechanical, and operational - that affect the loading function. The immediate objective of this work was to provide information for operations-research studies as applied to underground coal mining, and the broad objective was to provide guide¬lines for planning and equipment selection in underground coal mining. The loading function was expressed as -a statistically-developed linear mathematical model. Originally, fifteen independent variables were considered which potentially could have influenced the loading function. These variables were constructed on the basis of measurable or estima¬ble geometric and geological properties at the working face, mechanical characteristics of the mining machine, and certain operational proce¬dures of mining. The original model explained 64.0 percent of the experimental variation. The final condensed model explained 54.1 percent of the experimental variation in terms of only five indepen¬dent variables, namely: 1. Ratio: width of cut/total width of cutter 2. Ratio: height of cut/diameter of cutter 3. Total horsepower of cutter-drive motors 4. Rotation speed (RPM) of cutter 5,. A subjective estimate of machine quality and operator skill Certain limitations were found to exist in the evaluation of the variables. Principle among these limitations was the impossibility of precise measurement of tonnage loaded in certain instances.

Jan 1, 1972

By Larry R. Wilson

The development effort described herein was directed toward the design and development of a flexible communication system to provide two-way section communications between any telephone on an MCM-101 telephone FDM exchange and a miner provided with a uhf walkie-talkie transceiver. The system also provides normal communication between miners within a working section through the uhf coupler interface repeater.

Jan 1, 1976

By McHenry Mosier

Although local conditions at each mining property affect the percentage of increase in drilling speed for a given reduction in gage of bit, the results of drilling tests conducted at the Mount Weather testing adit show such a large advantage in favor of the smaller gages that they should be indicative of the possibilities at most mines. GENERAL DISCUSSION Although it is common knowledge among miners that drilling speed increases with reduction in gage of bit, the large amount o this increase is not so universally realized, A recent Bureau of Mines4/ survey of drilling practices in 28 metal mines showed that the maximum gage of starters is 3 inches and that at 50 percent of the mines starters are 2-1/4 inches or larger, Because this size appears too large for conditions at most mines where abrasion is moderate and where powder distribution permits, the use of smaller bits presents a favorable opportunity for reducing drilling costs.

Jan 1, 1939

By McHenry Mosier

Although local conditions at each mining property affect the percentage of increase in drilling speed for a given reduction in gage of bit, the results of drilling tests conducted at the Mount Weather testing adit show such a large advantage in favor of the smaller gages that they should be indicative of the possibilities at most mines. GENERAL DISCUSSION Although it is common knowledge among miners that drilling speed ill- creases with reduction in gage of bit, the large amount o this increase is not so universally realized, A recent Bureau of Mines4/ survey of drilling practices in 28 metal mines showed that the maximum gage of starters is 3 inches and that at 50 percent of the mines starters are 2-1/4 inches or larger, Because this size appears too large for conditions at most' mines where abrasion is moderate and where powder distribution permits, the use of smaller bits presents a favorable opportunity for reducing drilling costs.

Jan 1, 1939

Objective To characterize the roof fall risk associated with underground limestone mining. Background During the first 5 years of this decade, more than one-fourth of the underground mining fatalities occurred as the result of fall of ground. The large openings in underground stone mines present limitations in observing ground conditions because of floor-to-roof heights ranging from 20 to 60 ft or more. Generally, the status of ground conditions in under-ground stone mines is based on observation and experience obtained during mining development. Some mines use monitoring instruments to gain information on roof conditions, but this practice is typically focused and localized to address issues in a particular area or section of the mine. The Roof Fall Risk Index (RFRI) described here provides a method of systematically characterizing the risk of roof falls to enhance the safety of mine workers. Approach As in many industries, a defective product signals the potential for failure. Similarly, defective rock or strata in an underground stone mine presents a potential risk. Assessing ground conditions relative to the concentration of defects observed provides a way to index or rate these conditions and the subsequent risk. Through observations at approximately 50 underground limestone mines in the United States, strata defects were categorized to develop a quantitative method for determining the RFRI. This method is specifically geared to underground lime-stone mines because strata defects are difficult to see and limited by the experience and knowledge of the observer. Overall, 10 defect categories were deter-mined: 3 that relate to geology, 4 that result from mine development, 2 that are indicative of the roof profile, and 1 that addresses moisture or water flow (see RFRI Chart 1). The defect categories are also weighted to reflect the conditions indicative of roof or strata movement or separation (categories 4 through 8). These weights are multiplied by the assessment value to determine the total category value. The benefit of using monitoring techniques to gain information on roof conditions is also factored into the RFRI for overall assessment of an area in the mine. Each defect category is assessed with a value of 1 to 5 based on parameters as defined in each defect category, with 5 indicating the highest degree or level of defect. The assessment value of 3 is also used when information on a parameter is unknown. The parameters for the defect categories are illustrated in RFRI Chart 2 for use in determining the assessed value. How It Works The RFRI provides a means to categorize the risk for roof falls in underground stone mines. The concept of this calculation is aimed at providing an indication of the level or degree of defect relative to the area of the mine examined. The RFRI for the calculation produces a distribution where RFRI values approaching 0 represent a stable condition and those ap-proaching 100 represent an unstable condition.

Oct 1, 2006

By T. G. Carnahan

The Bureau of Mines conducted laboratory-scale weathering research on a leach residue containing elemental sulfur and mixed metal sulfides. Experiments were performed to determine pH and impurity element concentrations in the effluents as functions of time and to determine the effects on effluent concentrations of mixing the residue with dolomite tailing material. Four 800-day tests were conducted simultaneously. Soluble metal concentrations, especially zinc and copper, were excessive in the effluents from washed and unwashed samples of the residue. Concentrations of up to 20 g/l of Zn and 12 g/l of Cu were obtained. The pH values of the unwashed and washed residue effluents at the completion of the experiments were 2.8 and 1.9, respectively. Sulfuric acid from oxidation of pyrite caused the pH decrease. Mixing unwashed residue with dolomite tailing to maintain a near-neutral pH minimized the heavy metals content in the effluents. The pH in the dolomite tests increased slowly after the first 360 days and attained values of 7.8 and 8.2, respectively, for tailing containing 1 pct leach residue and for tailing devoid of leach residue. Dissolved zinc and copper did not exceed 0.10 g/l of Zn and 0.001 g/l of Cu.

Jan 1, 1982

By George S. Koch

In preparing diamond-drill core samples for assay at the Homestake mine, Lead, S. Dak., 5-foot intervals of core are processed through three stages, crushing, grinding, and pulverizing, and portions of the core material are discarded after splitting at each stage of preparation. Then two 1-assay-ton fractions are taken from the pulverized material and assayed. This report investigates alternative methods of sample preparation. The consequences of crushing, grinding, and pulverizing all rather than part of the core are appraised through the statistical analysis of assay results from 118 5-foot intervals of core. Evidently, a substantial improvement in precision at small additional expense is obtained by grinding most or all of the core before splitting. Pulverizing all of the core would be desirable only if doing-so would cost less than assaying five random splits from each interval. Graphs and tables detail appropriate procedures to obtain specified precisions. The experimental design and methods can be applied to similar problems in preparing core and other geological samples.

Jan 1, 1972

By G. Nuñez, M. A. Pathak, A. A. Afshari, C. F. Stanley

"To help evaluate the vibration patterns of an excised lung, a method is developed to determine which parts of the surface of an excised lung are responding to acoustic excitation via the trachea. Holographic interferometry, a very' sensitive technique ·that can measure movements of a few microns, is used to detect the lung surface movements.The intact lung and heart are excised from Long· Evans male rats weighing 250 gm. A tube is inserted into the trachea and connected via a funnel to a 3 inch cone speaker. The assembly is positioned in the holographic unit and excited at frequencies up to 10,000 Hz. The holographic unit contains an acousto-optic shutter used with a 0.5 watt Argon laser.The resulting reconstructed holograms contain interference fringes that are indicated of lung surface vibration.INTRODUCTIONA 1986 report by the U.S. National Committee on Biomechanics [1] describes diseases of the lung as a major national health problem. One of the recommendations of the report is for continued study of the mechanical properties of lung tissue. As an example, the report cites at least three areas that would benefit from a better understanding of the vibratory patterns or the lung."

Jan 1, 1989

By D. G. Lee

Diesel particulate matter (DPM) often contains small amounts of metal as a minor component but this metal may contribute to adverse health effects. Knowledge of the mechanism for particle formation as well as the size preference of the trace metals is critical to understanding the potential for health concerns. To achieve this, the size and the composition of each particle should be optimally measured at the same time. Single particle mass spectrometer (SPMS) would be the best tool for this objective. In this paper, we therefore will introduce new findings about the mechanism and distribution of the trace metals in DPM, derived from a study where an SPMS was used to analyze freshly emitted DPM. KEY WORDS : Single particle mass spectroscopy, Diesel particulate matter, Characterization, Metal contents

Jan 1, 2006

By A. W. Fahrenwald

"Cooperation was arranged between the mine operators, the Michigan College of Mines and Technology, and the Bureau of Mines for a study of present milling practice in the copper district of Michigan. Work was actively commenced in January, 1928.In Michigan copper occurs almost wholly as native copper. An insignificant amount of copper sulphide is present. The native copper occurs in two general classes of formations--namely, amygdalaid and conglomerate.In respect to ore dressing, the outstanding peculiarities of the two types of copper are: (1) In the amygdaloid, the relative coarseness of the metallic copper, which is almost completely liberated at approximately 48-mesh comminution; (2) the sprangly and flakey physical character of much of the liberated copper after crushing; (3) in the conglomerate, the extremely fine dissemination of the metallic copper, which is not completely liberated by crushing to -200 mesh.Because the study to date has been confined almost wholly to amygdaloid ores, the conglomerate class is not considered herein. The conglomerate ore is being efficiently treated, and the loss of copper is small.The amygdaloid ore contains a silicious gangue of which 80 per cent has a specific gravity of less than 2.84, 92 per cent of less than 2.94, and 98 per cent of less than 3.17. Epidote of 3.25 specific gravity is noticeably present, and accumulates on the table concentrators, from which it is hard to make clean con¬centrate and middling recovery.The general nature of the amygdaloid ores varies a little from mine to mine, but the general characteristics are the same, as is shown later by flotation tests."

Jun 1, 1928

By John P. Powell, J. L. Eakin

"INTRODUCTION AND SUMMARYNowata County, in the northeast corner of Oklahoma, is one of the principal oil-producing counties of this stripper area. Many fields in the county were opened and much oil was produced before statehood. The location of the major fields, as defined by the Oklahoma Corporation Commission, 2/ the outline of the areas of water-flooding activity, and the location of the several projects described in detail in this report are shown in figure 1.There was some drilling in the county earlier; but it was not until after 1904, when the Secretary of the Interior confirmed as valid the leases granted by the Cherokee Nation, that the major drilling activity began. Initial development in this part of Oklahoma was in the Chelsea field in Rogers County, which adjoins Novata County on the south. The activity spread rapidly northward to the Alluwe and Coody's Bluff fields, and then to the Nowata-Claggett field. Continued exploration resulted in discovery of the Delaware-Childers field, where some wells having an initial production of 1,000 barrels daily were completed. Fields discovered and developed during the next few years included the Lenepah (Elliott), Adair, California Creek, Curl Creek, Woody, and South Coffeyville. The oil-production history of Nowata County is shown in figure 2. In assembling the data for a production curve, it was found that the combined production records for Nowata and Rogers Counties were available for 1914 to 1951, inclusive, and that records for the individual counties were available only from 1926 to 1951, inclusive. The early production figures for the counties from 1905 to 1914, inclusive, except for 1909, were calculated from the initial production statistics of the Federal Geological Survey mineral resources bulletins and production data assembled by C. H. Beal. 3/ The production values for 1905 to 1926 for Nowata County were obtained by dividing the total production for the two counties by a percentage factor derived from known facts regarding the oil industry in the area. Production figures for the individual counties from 1926 to 1933, inclusive, were obtained from the files of the Oil and Gas Journal, and the figures from 1933 through 1951 were obtained from monthly reports of the Oklahoma Corporation Commission."

Jun 1, 1952

By C. L. Klingman

In extracting helium from natural gas at Bureau of Mines helium plants, a continuous analysis of the helium content of inlet and outlet gas streams is required to determine extraction efficiency. An analyzer, using established principles of gas chromatography to effect the analysis, has been developed by the Bureau of Mines to meet this need. It will record the helium content of inlet or discharge gases from helium-extraction plants every five minutes, continuously, without the attendance of an operator. A 25-inch column of activated charcoal is used as a partitioning agent; nitrogen is the carrier gas; and a hot-wire, thermal-conductivity cell is the detector. A 1.0 mv, strip chart indicates the unbalance of the detector cell, Sample size is 0.37 cc, and carrier gas flow rate is 75 cc, per minute. Significant improvements in helium extraction have been demonstrated by using the chromatograph in three helium-extraction plants.

Jan 1, 1961

By Deno M. Pappas

The objective of this Bureau of Mines investigation was to identlfy and evaluate alternative binder materials for use in stabilizing and consolidating highly fractured roof along longwall faces and gate roads. The desirable characteristics of a stabilization material were defined, and an extensive search was conducted to find materials satisfying these characteristics. Of 20 materials originally scrutinized, 9 were chosen for laboratory analyses. The laboratory tests evaluated bond strength and tensile strength under both dry and wet conditions. An optimum material was not found. The laboratory analyses indicated two possible candidate materials for longwall stabilization: high-aluminous cement and two-component epoxy; however, the tensile strength of the high-aluminous cement was mediocre, and the epoxy cement is toxic, flammable, and fairly expensive. The potential market demand for an effective and economical stabilization macerial is discussed in the appendix.

Jan 1, 1988

By J. Croeni

The search for new alloys for application in the atomic energy field had prompted investigation of zirconium-rare earth metal alloys by the Federal Bureau of Mines. In this instance the zirconium-dysprosium system was investigated by melting point, thermal analysis, resistivity, X-ray and metallographic methods. Results indicate a single eutectic system with a peritectoid reaction occurring at 890° C. The eutectic isotherm extends from 30 to 95-percent dysprosium at 1,280° C. Eutectic composition is located at approximately 70 percent dysprosium. Solid solubility of dysprosium in both alpha and beta zirconium is extensive. The extent of solid solubility of zirconium in dysprosium has not been determined. Although zirconium rich alloys exhibit a significant increase in hardness, they can be cold worked extensively. These alloys also appear adaptable to solution heat treatment. Additional investigations concerning corrosion resistance and other mechanical properties are necessary for satisfactory evaluation of these alloys. The superior corrosion resistance of zirconium and the nuclear cross-section characteristics of the rare earth metals have stimulated alloy investigations using zirconium as a base metal. Alloys combining these characteristics present a possible substitute for hafnium as a control rod material. In this particular study dysprosium was chosen as the alloying element, and several series of alloys were used to establish the equilibrium diagram.

Jan 1, 1960