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Reduce longwall shearer operator's dust exposure by selecting the best drum water spray sys-tem for minimizing dust generated durinq cutting. Approach Three of the most commonly-used drum water spray systems were installed on the same set of shearer drums and compared to determine which system best suppresses dust. The spray systems studied were: ? pick-point flushing ? cavity filling ? water-through-the-it Instantaneous and gravimetric sampling instruments were used to measure the respirable dust exposures of the shearer operators and dust concentrations downwind of the shearer. The Three Systems: Longwall shearer drums are routinely equipped with internal drum spray systems since these systems have been shown to be more efficient than external systems in terms of dust suppression per gallon of water applied. All U.S. longwall shearer faces utilize some type of internal water delivery spray system. The two most common systems are bit-or pick-point flushing and cavity filling. Pick-point flushing uses nozzles mounted in the bit blocks or in special blocks immediately in front of the bits. Cavity filling utilizes spray nozzles installed in a pipe manifold mounted on the drum hub between the scrolls or along the edge of the vane scrolls; water is sprayed radially from the manifold towards the adjacent vane scroll.

Jan 1, 1986

By E. C. Lane

This paper is the first part of a report giving the results of the Bureau of Mines' twenty-third semiannual survey of motor gasoline marketed in the United States. A companion report, Part II, is in preparation and will give a more detailed discussion of the whole survey. Results of the determination of copper-strip corrosion, color, sulphur content, copper-dish evaporation residue, and gum content as given by the Bureau of Mines steam-oven method will be presented in the second paper, which will also include the prevailing retail price and the tax at the time the sample was taken. This paper deals specifically with data relative to gravity, Reid vapor pressure,5 and distillation (method 100.13).6 The samples tested were divided into "competitive-price gasolines" and "premium-price motor fuels," a method of presentation that was begun with the twenty-second semiannual survey.7 A total of 312 samples were collected from service station pumps in 20 cities throughout the United States. Of this number of samples, 207 were "competitive-price gasolines" and 105 were "premium-price motor fuels." All of the samples were collected in March, 1931, and analyzed at the Petroleum Experiment Station of the United States Bureau of Miner at Bartlesville, Okla.

Jan 1, 1931

By C. S. Allbright

This report gives the results of analyzing three groups of crude shale oils by the Bureau of Mines procedure:4/ (1) Oils produced by standard Fischer assay determinations on oil shales from Brazil (Paraiba Valley) and the United States (Colorado); (2) oils produced from Brazilian shale by different retorting methods; and (3) oils from high-temperature retorting of Colorado oil shale in the Entrained Solids retort. It is the second in a series presenting data obtained by analyzing crude shale oils from various sources. The series furnishes information on the general characteristics and compositions of a wide variety of shale oils. Use of a standard analytical method on all samples facilitates comparison of different oils. The 18 oil samples analyzed in this project comprised 3 from assays of Brazilian and Colorado oil shales in the Fischer retort, 9 obtained by processing Brazilian shale in various other units, and 6 from entrained solids retorting of Colorado shale at 1,000° to 1,500° F. The crude oils from Brazilian shale contained about half as much nitrogen as the Colorado oils. Properties of the Fischer assay oils from Colorado shales agreed with some data that relate grade of the oil shale with properties of the crude oil from the Fischer assay. Comparison of results from Fischer assays of oils from the foreign and domestic shales shows that the oil from Brazilian shale contains more low-boiling material and less residuum than either of the two from Colorado shale. This fact is reflected in lower specific gravity, viscosity, and carbon-residue values for the Brazilian oil. Retorting Brazilian shale in the Entrained Solids unit at 1,120° F. produced an oil whose boiling range was generally lower than the boiling ranges of oils obtained by processing in three other retorts at conventional temperatures. The quality of crude oils from high-temperature retorting of Colorado shale in the Entrained Solids process varies with retorting temperature. As the temperature is raised within the range 1,000° to 1,500° F., the amount of the naphtha fraction in the crude oil increases to about 35 percent and the aromaticity to 98 percent.

Jan 1, 1956

By Frank E. Scott

During the past year interest in the use of hydrazine and hydrazine hydrate as a fuel has increased in the United States; For this reason it was felt to be desirable to obtain information on the explosives properties (if these materials in order that hazards inherent in their manufacture, storage, transportation, and use might be evaluated.

Jan 1, 1949

By C. P. Lazzara, R. A. Franks, G. F. Friel, J. C. Edwards, J. J. Opferman

A series of four coal combustion experiments was conducted at the National Institute for Occupational Safety and Health's (NIOSH) Pittsburgh Research Laboratory (PRL) in the Safety Research Coal Mine (SRCM) to evaluate the response of fire sensors to a small 0.61 m square smoldering coal fire which transitions to flaming combustion in the presence of diesel emissions. An optical path smoke sensor alarmed earlier than a point type diffusion mode ionization smoke sensor which alarmed prior to a CO alert value of 5 PPM above ambient. The presence of steady state diesel emissions resulted in a decrease in the optical smoke sensor analog output voltage signal by less than 1.4 pct for the three coal fire experiments in which a diesel engine was operating, whereas the ionization smoke sensor output decreased between 10.8 and 26.7 pct after the initial surge of the diesel engine. A commercial diesel discriminating fire sensor did not alarm for a fire in the one experiment for which it was used. The results of the experiments demonstrated that an optical path smoke sensor might be used to detect a coal fire under the experimental conditions considered of starting a diesel engine followed by a slowly developing coal fire.

By J. C. Edwards, C. C. Hwang

A Computational Fluid Dynamics (CFD) program was used to model buoyancy induced Product-Of-Combustion (POC) spread from experimental fires in the National Institute For Occupational Safety And Health (NOSH), Pittsburgh Research Laboratory (PRL), safety research coal mine. In one application, the CFD program was used to predict spread from fires in an entry under zero airflow conditions. At a location, 0.41 m below the entry's roof at a distance of 30 m from the fire, the measured smoke spread rates were 0.093 and 0.23 m/s for a 30 and a 296 kw fire, respectively. The CFD program predicted spread rates of 0.15 and 0.26 m/s based upon the measured fire heat production rates. Based upon a computation with [c3h3] as the hydrocarbon fuel, a predicted 5 PPM co alert time of 70 s at a distance of 30 m from the fire is to be compared with the measured alert time of 148 s. In a second application, the CFD program was used to analyze smoke flow reversal conditions, and the results were compared with visual observations of smoke reversal for 12 diesel fuel fires. The CFD predictions were in qualitative agreement with visual observations of smoke reversal.

By Ivette E. Torres

Of the 15 selected non fuel mineral commodities detailed in table 12, only 3 indicated increases in worldwide consumption in 1992. As in 1991, decline in consumption levels of the selected commodities can be attributed to reduced levels of use in the former U.S.S.R. and Eastern Europe. Of the remaining 12 commodities, 2 magnesium and cadmium, stayed relatively the same, while the other 10, including iron and steel, all recorded decreases. Global consumption of iron ore is estimated to have fallen about 3.5 % or about 30 million tons. This is a greater decline than what was estimated for production of iron ore, which is down only 2.7% or nearly 26.5 million tons, suggesting an addition to stocks. The consumption trend for iron and steel has been declining since 1989. This has mainly been due to the continued drops in use in the former U.S.S.R. and Eastern Europe. Even as the European economy begins to turn upward, there may only be a slight increase in consumption of iron, steel, and cement, considering the high cost of construction needed to modernize factories and buildings in Eastern Europe. Many feel that the economies of these countries are limited by the current status of their industries.

Jan 1, 1994

By L. L. Oden

The Bureau of Mines analyzed vapor-aluminum-diffused stainless steels prior to conducting corrosion measurements in severely sulfidizing environments. These studies were conducted in response to the national need to better control the environmental and economic costs of corrosion. Specimens of a ferritic alloy and austenitic alloys types 316 and 310 were treated by a proprietary vapor-aluminum diffusion process and a dual vapor-aluminum diffusion process. Weights and dimensions were recorded before and after treatment, and comprehensive metallographic, X-ray, and electron micro-probe analyses were conducted for both single-and dual-vapor-aluminum-diffused specimens. Surface aluminum concentrations ranged from 26 to 34 wt-pct for all alloys. Dual treatment increased the quantity of aluminum per unit area by a factor of 2 and increased the depth of penetration by a factor of 3. The aluminum-diffused region of the ferritic alloy was single-phase aFe solid solution that was ordered on the surface, whereas two distinct diffusion layers were ob-served on the austenitic alloys. The outer layer comprised aFe solid solution that was ordered on the surface, and the inner layer was a two-phase mixture of aFe solid solution and the interrnetallic compound AINi.

Jan 1, 1982

By Arnold O. Tanner

The recession that took hold of the domes-tic mining industry in 1981-82 finally abated somewhat in 1987, resulting from increases in many commodity prices, especially in the metals sector, and from continuing success in lowering operating costs. By no means was the work finished; the mining industry was in a sense entering a new era. The struggle for survival was still very evident for many companies and various commodities, but increasing productivity and profits were accompanied by indications that these trends were more long term than short term. Raw nonfuel minerals produced in the United States during 1987 had an estimated value of $26.3 billion, an increase of $2.9 billion over the 1986 value. This is the fifth consecutive year that the value has increased. Except for a decrease in 1982, the value each year has increased since 1971, or 15 of 16 years. The value of raw metals production increased by an estimated 28%, an impressive improvement since the drastic fall in 1982. Industrial minerals growth was comparatively flat, with an estimated in-crease in value of 0.1 %, continuing a trend of the previous 2 years. Metal mine production dropped considerably in 1982 and maintained its resultant lower level until 1987, when production significantly recovered.

Jan 1, 1989

By R. V. Ramani, J. Qin

"During the mining process, the insitu material is broken into different size ranges, from very, large pieces to very fine particles. Some of the fine particles become airborne. In underground coal mining, airborne respirable. dust is associated with health and safety of the miners: The amount and size distributions of airborne dust are important parameters to effective dust control measures. The design of underground mine experiments, including sampling procedures and sample analyses methods to determine these parameters are presented in this paper.. A total of fifteen continuous miner cuts were sampled. The amount of dust generated during the cutting process and the relationship between total and respirable airborne dust concentrations and amounts are examined.The amount of respirable dust airborne is on the average only. 0.016% of the respirable dust generated. On the average, 61% of the total .airborne dust measured is in the respirable size range. The amount of respirable airborne' is on the average 36% of the respirable size fraction in the total airborne dust. For equal proportion of rock and coal material cut, rock contributes about twice as much fines (<0.22 mm) as coal. Additional fundamental research is necessary to further the understanding of 'the airborne propensity of respirable dusts in mine atmospheres.INTRODUCTIONMining is a sequential process of breaking, gathering, loading, and transporting the in-situ .materials.' In underground coal mines, duet in both the non-respirable and respirable size ranges is generated and entrained in every phase of the process. Even though large amounts of dust particles' adhere to run-of-mine coals, part of the dust generated becomes airborne (Cheng and Zukovich, 1973). Studies have shown that bit type affects the amount of dust generated'(Evans and Pomeroy, 1966; Kurth et al., 1975; Roepke et al., 1976; Stecklein et al., 1982; and Khair and 'Reddy, 1986). Deep cutting can reduce airborne dust generation (Black and Schmidt, 1977 arid, Black et 1978). Mechanical properties of. coal seams are also important factors in dust generation. Laboratory studies have shown that Hardgrove Grindability Index (HGI) of the coal has a relationship with the amount of respirable. dust generated (Beafi and Ramani, 1979; Moore and Bise, 1984; and Moore, 1986). However, these relationships have not yet been validated with' data from the mines. The amount of dust airborne depends on a number of factors. Suppression of the airborne propensity of dust by water sprays is'widely practiced and is very effective. Water flow rate; pressure and configuration of water sprays have been identified as major factors affecting dust capture by sprays (Courtney and Cheng, 1977; Courtney et al., 1978; and Kissell et al., 1979). Ventilation is a very important means of controlling the dust level at the coal face (Jayaraman, 1977). According to a National Academy of Sciences study (1980), the mechanism of dust generation and the process by which the generated dust becomes airborne are complex and not yet completely understood coal seams are also important factors in dust generation. Laboratory studies have shown that Hardgrove Grindability Index (HGI) of the coal has a relationship with the amount of respirable dust generated (Beafi and Ramani, 1979; Moore and Bise, 1984; and Moore, 1986). However, these relationships have not yet been validated with data from the mines. The amount of dust airborne depends on a number of factors. Suppression of the airborne propensity of dust by water sprays is widely practiced and is very effective. Water flow rate; pressure and configuration of water sprays have been identified as major factors affecting dust capture by sprays (Courtney and Cheng, 1977; Courtney et al., 1978; and Kissell et al., 1979). Ventilation is a very important means of controlling the dust level at the coal face (Jayaraman, 1977). According to a National Academy of Sciences study (1980), the mechanism"

Jan 1, 1989

By R. V. Ramani, R. Bhaskar

"An airborne dust cloud is an ensemble of particles of varied size, density, shape and states of aggregation. An understanding and quantifying of the dispersion and deposition of the du.st generated in mines is essential to the development of measures for reducing worker exposure to dust.In coal mining, the major portion of the dust is generated during the cutting of coal using a shearer or a continuous miner. The major phenomenon affecting ambient concentration is the deposition of dust. Panicle deposition may take place due to the effect of gravitational, inertial, electrostatic, and thermal forces, and mechanisms such as Brownian and eddy diffusion and inenial impaction. The three major mechanisms of deposition in turbulent flow in mines are diffusion (Brownian and eddy), sedimentation and inertial impaction. The mechanisms determining panicle deposition are size dependent.From a review of the literature, there appears to be a knowledge gap in the understanding of the deposition phenomena in mine airways. In order to obtain a better understanding of the deposition of dust for various particle sizes, and to develop a set of data for evaluating predictive mathematical models/or dust flow in mines, a series of dust-flow experiments was performed under controlled conditions in mine airways. It appears that the deposition data generally follow the theoretical behavior of dust based on the combined effect of diffusional and gravitational deposition. Jn this paper, the findings of the study on the deposition of dust in mine airways and its dependence on size, velocity and concentration are discussed. A set of deposition equations that could be used to determine the approximate deposition at various points in a mine airway are presented.IntroductionThe major factor affecting ambient dust concentration in mine airways is the deposition of dust. Particle deposition may take place due to the effect of gravitational, inenial, electrostatic, and thermal forces, and mechanisms such as Brownian diffusion, eddy diffusion and inertial impaction. The major mechanisms of deposition in turbulent flow in mines are diffusion (Brownian and eddy), sedimentation and inertial impaction. Inertial impaction is significant only during changes in direction, but the change in direction of flow with resultant powerful eddies may cause increased re-entrainment of the particles, thus having a compensating effect. While the literature in aerosol sciences contain several references on deposition, most studies were done in small diameter tubes for diffusional deposition (Liu and Agarwal, 1974). The deposition data from small diameter, short tube experiments may not be applicable to studying deposition in mine airways that have large areas and extend several hundred meters. Further, the change in concentration along the length of a mine airway may significantly affect the deposition an aspect that may not be easily determined in short tubes in laboratory experiments."

Mar 1, 1992

By R. L. Bolmer

Driving long development raises probably is one of the most hazardous and expensive operations in underground mining. The safe handling of men and materials becomes more difficult and more time consuming in the higher sections of the raise. The efficient ventilation of these sections often is a major problem. This information circular describes a unique method by which Resurrection Mining Co, safely and efficiently completed a 622-foot vertical raise at its Irene shaft near Leadville, Colo. The method used by the company involved driving a raw, 6-foot-diameter ventilation raise and emergency escapeway, using a work cage that was suspended on a hoisting rope extended down a small-diameter drill hole. Although the method was new and experimental, the raise was completed in record time. Overall costs were less than they would have been with conventional methods. The company&apos;s initial experience suggested improvements both in design and operating technique that should prove of value to others who contemplate using the cage method of raising

Jan 1, 1958

By F. E. Joyce

The Bureau of Mines studied copper-nickel minerals (mainly sulfides) of the Duluth Gabbro Complex in north-eastern Minnesota to determine their response to selective high-temperature sulfatization techniques. The gabbro, containing 0.44 percent copper and 0.13 percent nickel, was ground to minus 325 mesh and sulfatized in a heated, rotating, stainless steel bench-scale retort. Tests demonstrated that over 95 percent of the copper and 80 percent of the nickel can be converted to water-soluble sulfates, depending upon the roasting conditions employed. Yield equations were developed using regression analysis for predicting the extraction of copper and nickel between the temperature limits of 520° to 670° C, the roasting time limits of 3 to 7 hours, and S02 limits of 10 to 40 percent in S02-air mixtures.

Jan 1, 1971

By F. A. Rutledge

Mercury deposits were discovered in 1941 in the sedimentary rocks of the Cinnabar Crook area, near the head of the Holitna River drainage in southwestern Alaska, by Russell Schaefer and Harvey Wincholl of Sloitmut, Alaska. High-grade float was found in both Canary Gulch and Cinnabar Gulch, and indications of other deposits wore found in Aldor and Broken Shovel Gulches. Schaefer and Winchell&apos;s exploration in 1942 and 1943 revealed placer deposits of cinnabar along Canary Gulch. During prospecting on Canary Gulch, 3,600 pounds of ore was recovered from the detrital material on the Lucky Day lode at the head of the gulch. When retorted, this ore was reported by the owners to have produced 26 flacks of quicksilver. During the summer of 1943, Wallace M. Cady and Charles A. Hickcox, of the U. S. Geological Survey, spent 4 weeks mapping and investigating the area. Bruce I. Thomas and Harold C. Pierce, mining engineers of the Bureau of Mines, examined and sampled several deposits in September 1943. Following their preliminary examination, in view of the exceptionally high-grade cinnabar present, additional investigation by the Bureau of Mines was recommended. A program of trenching, test pitting, and sampling to delimit the deposits was completed during the summer of 1947 under the direction of the author.

Jan 1, 1950

By J. R. Thoenen

In June 1929 the Bureau of Mines issued a 13-page Information Circular entitled "Mineral wool." This was one of the first publications to present to the public some technical aspects of the mineral-wool industry. Since that time several articles have appeared on the subject in the technical press as well as publications by State organizations. Inquiries for information on mineral wool have continued to be received by the Bureau of Mines in large numbers, and in 1935 it was decided, with the cooperation of the is industry, to make a field survey of the plants then producing and to collect therefrom technical data to be compiled in a paper for public distribution. As a first step, a brief questionnaire was mailed to the known producers asking if they would cooperate for publication. Favorable replies were received from of percent of the manufacturers, and the field work was started. As the study progressed and tie number of plants visited grew, it became more and more apparent that the industry had made rapid strides in technical operation and control of their product, as well as in increasing production during the mast decade.

Jan 1, 1938

By G. W. Birge, D. E. Wolfson, J. G. Walters

Seventeen samples were carbonized by the BM -AGA pilot - plant test method and in industrial ovens . Chemical and physical properties of the samples were determined , and the physical properties of the cokes prepared by the two methods were compared . Since the capacity of the plants from which these samples were obtained is about 30 percent of the 1959 total for the United States , the data given in this report are indicative of the chemical and physical properties of blends used to produce industrial cokes and the acceptable chemical and physical properties of the resultant coke .

Jan 1, 1964

By Craig M. Jensen

A laboratory assessment of prompt and delayed neutron activation analysis with 252Cf and 14MeV neutron sources, for use as an in-situ method of determining low-level copper concentration has been performed. A simulated borehole using porphyry ore was constructed and varying copper concentrations were simulated using copper rods. Prompt neutron activation analysis experiments were consistant with earlier work and do not appear to be feasible fur copper concentration of 1.5% or less. Delayed neutron activation analysis experiments indicate that copper ore concentrations of less than 0.1% are detectable using either the 511-KeV gamma-ray of copper-64 or the 1039-KeV gamma-ray of copper-66, with high resolution detectors such as Ge (Li) or intrinsic germanium.

Jan 1, 1977

By S. R. Zimmerley

Recent investigations of finely ground materials have verified Rittinger&apos;s law of crushing.4, This law states that the surface produced is proportional to the work expended in the crushing operation. Thus, for a unit of work applied to crushing quartz a definite amount of surface will be produced. Obviously, this amount of work applied to some other mineral will not produce equivalent surface. It follows that in an investigation of mill practice, where ore is being crashed, the relative crushing resistance of the component minerals must be known. In a previous investigation of the Rittinger law,5 the crashing resistance that is, the work required to produce a unit of surface - was accurately determined for quartz. The surface values were obtained by means of the rite of dissolution of quartz in hydrofluoric acid.6 If it were possible so to measure surface on other minerals the determination of relative crushing, resistance would be a simple matter; however, the results obtained on minerals other than quartz by a dissolution method were not encouraging. Moreover, if accurate values could be obtained by dissolution this method could probably never be used on a mixture of minerals such as occurs in an ore.

Jan 1, 1929

By Richard L. Sayrs

The Eve Mills deposit is in Monroe County, Tenn., near the southeastern corner of the State. The deposit was examined in February 1943 by a Bureau of Mines engineer, and drilling the property was recommended to increase the on: reserves enough to justify mining should war needs require it. The deposits were explored, by 32 diamond-drill holes totaling 11,649 feet during the periods from July 1943 to November 7, 1945, and from April 1944 to August 17, 1944. The drilling campaign disclosed a large area of mineralization. The ore, however, is apparently confined to long, narrow sheets. The indicated grade of the ore bodies blocked cut by the Bureau of Mines is 4.o8 percent zinc and 2.10 percent iron.

Jan 1, 1949

By Graham W. Marks, Clyde A. Bridger

"INTRODUCTION An electrolytic process for the preparation of metallic cobalt has been developed recently in the Bureau of Mines Experimental Station at Boulder City, Nev. Chemical analysis shows this cobalt to contain impurities in small percentages, chief of which is nickel. It is desirable to be able to determine these impurities spectrographically. This report is concerned with a procedure for the spectrochemical determination of nickel in cobalt.Previous spectrographic work on cobalt was done by Breckpot and Mevis,/ who used the method of homologous pairs of lines. However, it was felt that a more detailed investigation was needed, employing the method of internal standards.ACKNOWLEDGMENTWe are indebted to B. G. Knickerbockor and his staff at the Boulder City, Nev., station of the Federal Bureau of Mines for their cooperation, and particularly to Richard W. Lewis and Robert G. Sanderson, who prepared nickel-free electrolytic cobalt for us."

Feb 1, 1948