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By W. P. Yant

[At the majority of mines where flame safety lamps are used either as working lights or as a means of detecting gas, no check it made on this condition of the various parts of the lamp and their assembly other than a visual ink inspection. Although this inspection should be made carefully in view of tae serious consequence that may follow Vie use of a faulty lama, In many instances the inspection is of a perfunctory nature. The Bureau of Mines has therefore designed a small box or gallery for testing lamps for defects and improper assembly before they are taken into the mine. The test simulates the condition when a lamp is extinguished by its introduction into an explosive mixture and the operator attempts to relight the wick while the lamp contains the explosive mixture. This test is more rigorous than merely subjecting a lighted lamp to an explosive methane-air mixture. In the latter test the products of combustion tend to blanket the propagation of flame from within the lamp to the exterior, especially if there are defects at the top of the gauzes. Moreover, when the lighted lamp is subjected to an explosive methane-air mixture the methane builds up slowly within the lamp until the lower inflammable limit is attained, whereupon a feeble explosion occurs within. If the nonlighted lamps is first filled with the methane-air mixture that gives the maximum violence and is than ignited, the dampening effect of products of combustion is obviated and the strain on defects is]

Jan 1, 1930

By Floyd G. Anderson

The Federal Bureau of Mines promotes the use of safe and effective dust-collecting devices for rock drilling in coal mines. To insure that such devices are available to the coal-mining industry, the Bureau issues certificates of performance for dust-collecting systems and certificates of approval for dust collectors and rock drills or other mining equipment with integral dust-collecting systems that meet the requirements of an established Schedule.4/ Investigations are conducted under the provisions of the current revision of this Schedule by engineers of the Branch of Health Research. This circular describes briefly the requirements and procedure for obtaining certificates of performance or approval and lists equipment that has been certified as permissible under Schedule 25 or its revisions as of January 31, 1961. The names and addresses of companies to which certificates have been issued are listed alphabetically at the end of this circular.

Jan 1, 1961

By G. W. Jones, F. E. Scott

"INTRODUCTION As a part of its program of promoting safety in mining and other industries, the Bureau of Mines investigates the explosion hazards of combustible Gases, vapors, and solids. It also investigates various means and methods of controlling and mitigating explosions.Dichlorodifluoromethane, CC12F2, has been found to be very efficient as a quenching agent for methane flames. 4/ This substance is a gas at ordinary temperatures and pressures and is relatively nontoxic and stable at mod rate temperatures.Tremendous quantities of dichlorodifluoromethane were used daring the late war as an expelling agent for aerosol mixtures in ""aerosol bombs."" At one time during the war the demand for Dichlorodifluoromethane became so gent that there was barely enough of it to supply the Army and Navy and virtually none for civilian needs. During this period of scarcity the Bureau of Mines, in cooperation with the Bureau of Entomology, Department of Agriculture, investigated the possibility of substituting other materials in part for the dichlorodifluoromethane. It was required that the resulting mixtures be satisfactory expellant and noninflammable under all normal conditions of use."

Jun 1, 1946

By Robert W. Metcalf

The feldspars are a series of related aluminum silicates containing varying proportions of potash, soda, rind lime; smaller amounts of other minerals arc likely to be present as impurities. They comprise three principal types: Potash spars, microline and orthoclase (KA12Si208); soda feldspar or albite (NaA1Si308); and soda-lime e (plagioclase) fellspars. The last-named is an intermediate group ranging from albite through oligoclase, andesine, labradorite, and bytownite to anorthite or line feldspar (CnA12Si2O8), Minor varieties are barium feldspar or celsian and a potash-barium feldspar. Perthite is a mixture of orthoclase end albite in alternate layers. Graphic granite or "corduroy spar" is an intergrowth of feldspar and quartz characteristically in the ratio of 3:1. Cornwall stone is a natural mixture of feldspar, quartz, end kaolinite imported in former years in sizable quantity from Cornwall, England. (A similar synthetic mixture, including some fluorspar, has been blended and marketed in the United States as "Carolina stone".)

Jan 1, 1941

By Alex U. Miller

Since its beginning, the occupation of coal mining has been considered hazardous. It is true that there are hazards inherent in mining, but it is believed that most of them, at least, can be guarded against. Moreover, many man-made hazards can be eliminated by officials and workers adopting safer practices. Notwithstanding the hazards in coal mining, the fatal accident rate in the United States has improved. During the, period from 1911, to 1941, inclusive, the fatal accident rate varied from 5.35 to 2.22 per million tons of coal. With many handicaps during the war period, 1942-45, such as the lack of experienced manpower. and the, employment of untrained men, the increased average age of workers, and the shortage of equipment and supplies, the industry s ill further reduced its accident rate, so that it ranged from 2.30 to 1.724/ deaths per millon tons of coal. During 1944, 684,000,000 tons of coal was produced with a rate of 1.91, and during 1945, 631,000,000 tons was produced with a rate of 1.724/ deaths per millon tons of coal. The accident rate for 1945 was the lowest for the industry since records have been compiled.

Jan 1, 1946

By W. E. Wallace, C. A. Hill, M. J. Keane

"Diesel exhaust particulate material from exhaust pipe scrapings of two trucks, diluted automobile diesel exhaust particulate material collected on filters, and two oil shale ores were prepared for the Ames mutagenrcity assay by dichloromethane OOP ex¬traction, by dispersion into 0.85% saline, or by dispersion into dipalmitoyl lecithin (DPL) emulsion in saline. Salmonella typhimunum TA98 was used to detect frameshift mutagens in the samples. Samples of diesel soot gave positive mutagenic responses with both DCM extraction and DPL dispersion, with the DPL dispersion giving higher results in some cases. The results suggest that possible mutagens associated with inhaled particles may be dispersed or solubilized into the phospholipid component of pulmonary surfactant and become active in such a phase.INTRODUCTIONThe Ames Salmonella/microsome assay (Ames et al., 1975) has been shown to be a useful test for detecting genotoxic properties of various agents. Hundreds of specific chemicals have been screened (McCann et al., 1975), and the test has been applied for many types of environmental samples. Airborne mutagenic agents, for example, have been found in urban air (Chrisp and Fisher, 1980; Hughes et al., 1980; Ro· senkranz et al., 1978), in diesel engine exhausts (Huisingh et al., 1978), and in the by-products of coal combustion processes (Chrisp et al., 1978).Samples of airborne particles are typically collected on membrane filters, and undergo a rigorous extraction procedure with organic solvents and/or ultrasonic agitation (Clark and Hobbs, 1980). Often extracts are transferred to another solvent that is compatible with the assay system. These extraction procedures, while efficient from an analytical perspective, are not physiologically plausible. The questions that present themselves are whether a demonstrated mutagen can be taken up in vivo and whether the process is quantitatively or qualitatively different from the above laboratory procedure (Wallace et al., 1984).When a particle of respirable size is inhaled to the alveolar region of the lung, its first physiological contact is with pulmonary surfactant that lines the inner surfaces of the alveoli. This surfactant is an aqueous fluid containing proteins, phospholipids, and other components (R. J. King, 1982). The principal phospholipid constituent is L·alpha-phosphatidylcholine, beta,gamma-dipalmitoyl, or dipalmitoyl lecithin (OPL) (l. C. King et al., 1981)."

Jan 1, 1989

By R. W. Watson

This Bureau of Mines report summarizes some recent results on the sensitivity of various experimental explosive systems using ammonium nitrate (AN) as the oxidizing agent. The sensitivity survey included drop-weight and friction testing and sensitivity to initiation by projectile impact and a No.8 blasting cap. It was found that certain types of AN prills can result in cap-sensitive mixtures when combined with No.2 diesel fuel (Fa); prilled AN mixed with nitromethane also result in cap-sensitive mixtures. Mixtures of AN prills and neat 1-and 2-nitropropane were not cap-sensitive, and the use of powdered or grained aluminum in AN-FO did not adversely affect the sensitivity except possibly to increase its sensitivity to friction.

Jan 1, 1974

By K. Robert Dorman

Spray-applied polyurethane foam was used to insulate the walls of heated rooms excavated in permafrost. The experiment was designed to determine whether polyurethane foam can be sprayed successfully on frozen ground under freezing conditions and to measure the effectiveness of the insulation in maintaining--at elevated temperatures for an extended period--a room excavated in frozen ground. Two manufacturers' foams were investigated in the laboratory. Subsequently, one of the foams was employed to insulate two small rooms, one in frozen gravel and one in frozen silt, in an experimental tunnel belonging to the U.S. Army Cold Regions Research and Engineering Laboratory (USACRREL) near Fairbanks, Alaska. Following insulation, heat was introduced into the two rooms. Heat migration across the insulating barrier into the walls, in addition to wall closures, was monitored over an 8-month period. The results show that polyurethane foam can be successfully sprayed on frozen ground in below-freezing temperatures. Given this type of insulation, together with winter cold to supercool the surrounding ground, it should be possible to maintain a shaft or heated room in permafrost for several years.

Jan 1, 1970

By Doug Scott

Develop tools that companies can use to comply with 29 CFR 1910.1200.

By M. G. Zabetakis

This publication presents a simplified graphic method for determining the explosibility of mine atmospheres under mine-fire conditions from mine- atmosphere composition data. Sometimes it is necessary to seal part of a mine during a fire to exclude air and thus extinguish the fire. Unfortunately, liberation of methane and formation of hydrogen and carbon monoxide in the sealed area may create an ex- plosive or flammable atmosphere if enough oxygen is present to support combustion. On the other hand, the oxygen concentration may be reduced through combustion processes and the concentration of inert gases (nitrogen and carbon dioxide) increased enough to render the atmosphere within the sealed area non-explosive. Before an area is unsealed, it is extremely important to know if the sealed atmosphere contains Flammable gases in proportions that might form explosive mixtures when air is introduced. If an explosive mixture forms and the fire is rekindled, a gas explosion will result. Various experimental methods may be used to determine the explosibility of a particular mine atmosphere; however, these methods usually are impracticable in the field.

Jan 1, 1959

By C. R. Bopp, N. A. C. Smith

"For a period of several years, beginning with 1915, there has been a continuous change in the quality of motor gasoline. The average volatility has decreased, this to the fact that higher boiling fractions of the crude oil have been included in the gasoline. This change in quality was made necessary by the tremendous increase in the demand for motor fuel, caused by the development of the motor car, and during the war was an absolute necessity to avoid gasoline shortages. The Bureau of Mines has kept in close touch with this situation by making surveys from time to time of the gasolines sold throughout the country, as this information is of value to manufacturers and users of motor cars and also indicates when any changes are required in the Government specifications. The Bureau has just completed a gasoline survey and is in a position to make public the fact that there has been very little change in the quality of motor gasoline in recent months.During the period from January 17 to February 3, 1920, 81 samples of actor gasoline were collected by representatives of the Bureau of Mines in seven districts of the United States. The cities selected for this survey were New York, N. Y., including Brooklyn; Washington, D. C.; Pittsburgh, Pa.; Chicago, Ill.; New Orleans, La.; Salt Lake City, Utah; and San Francisco, Cal., including Berkeley. In every case the samples collected were taken in such a manner as to represent material actually being sold as motor fuel, and to include samples from each refinery marketing in the district."

Jan 1, 1920

Develop and evaluate a mechanical position and heading system (MPHS) that provides information about underground mining machine position and heading to aid in the remote positioning of mining machines during face maneuvers. Background While great improvements have been made in mineworker safety, progressive technology continues to create a safer, better working environment for miners by keeping them away from the dangerous face area. In maintaining such high standards of safety, the Bureau is investigating remote, computer-assisted operation of mining systems for underground, highwall, and surface mining applications. A key component of computer-assisted operation is a guidance system. Since there are no guidance systems on any commercial continuous mining machines, the Bureau itself developed and tested the mechanical position and heading system (MPHS). The MPHS is based on linear position transducers (LPT's), and operates on principles of triangulation to provide machine position (xy coordinate), and orientation in the xy plane (yaw or heading). These data are needed in order to keep the continuous mining machine in proper alignment before and during the cutting cycle. The MPHS theory development is in three parts: characterize the sensors used and their configuration; select and define the navigation reference frames; and derive a closed-form solution for determining the position and beading from sensor information. Application of the MPHS theory required the development of hardware, software, and system interfaces.

Jan 1, 1992

By S. J. Pearce

There are a number of methods for determining relatively small quantities of sulfur dioxide in air. However, those methods require fairly elaborate apparatus and laboratory facilities. Frequently in industrial hygiene surveys it is desirable to have a simple arrangement to obtain "on the spot" determinations. This has been accomplished for concentrations of sulfur dioxide of hygienic significance by using the midget impinger and decolorizing a starch-iodine solution.

Jan 1, 1948

By M. M. Jones

Natural brines are potential domestic resources of minerals. The brines of Searles Lake, CA, for example, contain an estimated one-fourth of our current reserve of tungsten. A key to Bureau of Mines research to recover this critical mineral is the ability to quantitatively measure concentrations of particular constituents in the large number of brine samples and process solutions produced under a multiplicity of test conditions. This paper describes procedures used to determine arsenic, boron, phosphorus, silicon, and tungsten in these solutions by simultaneous inductively coupled plasma spectrometry. A variable in-ternal standard method was used to compensate for tungsten interference on the other analytes in tungsten concentrates, and matching standards were used to determine tungsten in raw brine. Other solutions were analyzed using normal techniques. Analytes were determined down to 1 mg/L with an average precision of 2.5 pet relative standard deviation. Accuracy, estimated using synthetic solutions and by comparison with values obtained by other methods, averaged about 2.5 pet. The methods were rapid, required little sample preparation, and provided the needed sensitivity.

Jan 1, 1985

By L. B. Berger, S. J. Pearce

One phase of Bureau of Mines' work in health and safety is promotion of the use of safe, satisfactory, and reliable respiratory protective. devices. To insure that such devices will be available, the Bureau has established schedules of minimum requirements for self-contained breathing apparatus, gas masks, supplied-air respirators. (hose masks, air-line respirators, and abrasive blasting helmets, hoods, or masks), dispersoid (dust, fume, and mist) respirators, and nonemergency gas respirators (chemical cartridge respirators). Approval tests of self-contained breathing apparatus are conducted by the Safety Branch; approval tests of other types of respiratory protective equipment are conducted by the Health Branch. Both branches are in the Health and Safety Division.

Jun 1, 1950

By X. B. Starnes

"INTRODUCTION The Eva Tanguay property is in Crittenden County, Kentucky, about 1 mile south or the village of Mexico, and can be reached from Marion, the County seat, by travellng south on State Highway 91 for 6.8 miles and then turning southwest on State Highway 70 and traveling 2 miles farther.Although the property lies between the Huffaw and Pigmy properties, which together have produced 200,000 tons of fluorspar ore, production from the Eva Tanguay has been estimed at only 1,000 tons. Geological factors on the property indicated the likelihood of an ore occurrence, and the author examined the property in April 1944. Shortly thereafter, the U.S. Geological Survey wrote a report on the property, which was not published. A drilling program was initiated by the Bureau of Mines November 1, 1944, and continued until eight holes totaling 3,137.5 feet were drilled.The holes showed that the Tubb fault system on the Eva Tanguay property is composed of three members, all of which contained commercial ore. The line dividing the Haffaw and Tanguay properties crosses the vein outcrops, causing a part of the ore indicated to be on each property.The mineral rights, which are leased by Robert Frazer of Marion, are owned by Mrs. O. S. Denny and W. C. Bohn, both of Marion."

May 1, 1947

By Danqing Xu, A. W. Khair

"This paper presents a laboratory simulation of regrinding and resulting dust generation. An Automated Rotary Coal Cutting Simulator (ARCCS) was modified to conduct regrinding experiment. In order to estimate the effects of coal properties and operating parameters on regrinding and dust generation, an orthogonal fractional factorial experimental design was implemented in regrinding experiment. Marple personal cascade impactors, Series 290, were used to measure dust concentration during experiment. Three types of coal seams, namely, Waynesburg, Pittsburgh, and Lower Kittanning, were used to represent different coal properties. Experimental results and complete parametric analysis were presented.In a rotary cutting system, all the broken coal and part of the remaining coal from previous cutting cycles must be transported through part or entire circumference of the cutting drum. This transportation of already recovered coal through the cutting zone of rotary head makes it a rotary grinder. Some of the coal particles will be subjected to secondary fragmentation or regrinding in the process. The potential effect on dust generation by regrinding is significant because the cutting head utilizes kinetic energy to comminute recov¬ered coal material. The moving bits and bit blocks on the cutting head impact coal particles and transfer some of their kinetic energy to the particles. After obtaining kinetic energy, coal particles are free to impact one another and they also impact the coal seam or cutting head. During impact, high impact force and high internal stress concentration are created in the particles. Kinetic energy is transformed into strain energy. When stored strain energy exceeds allowable strain energy, the particles will break. A great amount of respirable dust will be generated due to impact failure. In reality, regrinding occurs at the same time as primary cutting. The particles to be ground are the result of primary cutting. Both primary cutting and regrinding produce dust. Therefore, it is impossible to separate regrinding from primary cutting. In order to study respirable dust generation by regrinding and analyze the influencing parameters, a laboratory approach was adopted. In this approach, it is possible to study the regrinding separating from primary cutting."

Mar 1, 1992

By L. H. Duschak

"This paper is based on the results of work conducted of the bureau's experiment station at Berkeley, Calif., in connection with the investigation of properties and methods of utilizing Western magnesite. The experiments described herein were made under the supervision of the writer, by W. C. Riddell and E. H. Delius, of the station's staff.In calcining magnesite for the production of magnesium oxide to be used in the preparation of oxychloride cement, the calcium carbonate present in the original rock may remain unchanged or appear in the finished product, either as CaO, or in combination with SiO2, A12O3, etc. As there is reason to believe that free CaO may have an effect on the behavior of caustic magnesia in the cement reaction, it is desirable to have a method for the determination of the relatively small amounts of free CO in the presence of a large quantity of MgO.The extraction of the free CaO with water free from CO2 at once suggests itself as a possible method. The solubilities of Ca(OH2)2 and Mg(OH)2. are given by Seidell in his book an ""Solubility of Inorganic and Organic Compounds."" (2nd Edition, 1919) as follows:"

Jun 1, 1920

By Allen D. Look

Use of two-way radio communication at the Santa Rita open pit of the Kennecott Copper Corp. has furnished a satisfactory answer to the problem of communications for an operation covering an extended area. Coordination of operations has resulted, with little loss of time in making changes during the shift. Repairs are facilitated, and safety of operations is increased through better control of blasting and hazardous conditions. INTRODUCTION Expansion of mining operations brings increasing needs of improved communications to coordinate the mechanized operations that contribute to the efficiency of present-day open-pit methods. Equipment found satisfactory when first installed becomes inadequate as distances and demands increase. It is the, purpose of this paper to record the progress being made by one mine in meeting this problem.

Jan 1, 1952

By L. G. Marshall

The geology, mining, beneficiating, types of products, and costs in terms of percent of total costs and of labor, power, and supplies of two crushed- limestone operations in Madison County, Iowa, are described in this paper. The operations are basically similar, differing in refinements in mining, product types, and markets. The operations are comparable as to personnel and as to weighted costs in terms of percent of total costs and in terms of man-hours, power, and supplies. The waste-to-stone stripping ratio is 1 to 0.8 at both operations, the powder factor is 0.29 pound of explosives per ton of stone, and daily production is 95 tons per man-shift. Both companies use crawler-mounted diesel shovels for loading, truck transportation, wagon drills, and dry screening.

Jan 1, 1963