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By R. Y. Williams

The investigative work described in this report was undertaken by the Bureau of Mines under a cooperative agreement with the department of mining engineering of the University of Illinois and the Illinois State Geological Survey." The purpose of this agreement was to provide for a comprehensive investigation of coal-mining conditions in the State, with especial reference to the possibility of lessening waste in the mining and preparation of coal and of reducing the dangers to which miners are exposed. The Bureau of Mines paid particular attention to those phases of the investigation that were of general interest from their bearing on safety and efficiency in the coal-mining industry as a whole. Thus, it studied the occurrence of gas (methane) in the mines of the southern part of the State," tested the inflammability of the coal dust from many mines, examined the efficiency of the control of ventilating currents, and investigated the factors affecting the humidity of mine air with respect to their bearing on the occurrence of mine explosions. Following the establishment of the fact that under certain conditions dry bituminous coal dust is inflammable, there arose the problem of finding efficient methods of preventing or limiting coal-dust explosions. Experiments in the gas-and-dust gallery at the Pittsburgh testing station of the Bureau of Mines verified the fact that certain dusts that explode violently when dry are rendered inert by proper humidi- .fication of the atmosphere within the gallery, and the importance of humidity as a factor in limiting the inflammability of coal dust in a mine is demonstrated by the fact that there has never been in Illinois a dust explosion during the summer months, whereas the records show a number of dust explosions during cold weather. It is easy to see that the warm moisture-laden air that enters a mine in the summer must deposit moisture on cooling, whereas the cold and relatively dry air that enters in winter must take up moisture as it becomes heated in traveling through the mine.

Jan 1, 1914

By R. H. Lien

The Bureau of Mines has conducted research on a flue gas desulfurization (FGD) process as part of its goal of minimizing the undesirable environmental impacts associated with sulfur dioxide (S02)-bearing waste gases. This FGD process, referred to as the modified citrate process, involves absorption of S02 in a buffered citric acid solution. The absorbed S02 is subsequently stripped from the solution using steam, which regenerates the solution and produces a wet S02 product. This product can be further processed to make sulfuric acid or liquid S02. Economic evaluations showed the process to be expensive when the stripper was operated at or near ambient pressures because of the large amounts of steam required for solution regeneration. Research was directed at reducing steam consumption in the stripper. The effect of stripper pressure on steam consumption was investigated. A process research unit (PRU) was operated with the stripper pressurized in the range of 5 to 150 psig. Test results showed that steam consumption decreased with increased stripper pressure. For example, when operating the PRU stripper at 150 psig, 4.1 grams of steam per gram of S02 was required to remove 90 pct of the S02 from a 1.0-vol-pct-S02 gas. This compares to 7.1 grams of steam per gram of S02 required for 90-pct S02 recovery at 5 psig.

Jan 1, 1982

By R. W. Smith, S. H. Ash

Marked progress in safety has characterized the operation of coal mines in general in the State of Washington during the 5- year period 1928-1932 , particularly during the years 1931 and 1932. Physical conditions such as steep pitches , inherently bad roof and floor , prevalence of gas , and explosibility of the dust of Washington coals present certain definite hazards . Although advances have been made in accident reduction in Washington , the State still has far to go in that direction . The State has endeavored to reduce its coal -mine accidents by the usual method of making certain definite safety requirements mandatory . The value of education has not been underrated , but the educational method used has not altogether achieved the res lts desired by the industry itself , particularly within certain imdividual organizations . The past 2 years have witnessed a growth , in certain instances , of the essential ideas that the observance of safety precautions on the part of all is demanded if accidents are to be reduced , and that the initiating and carrying out of any program to promote and obtain desired results in accident elimination must begin and function from the top downward . Mining operations of Washington mines have been described in various publications of the United States Bureau of Mines .

Jun 1, 1933

By L. W. Kelly

The purpose of this paper is to indicate some of the benefits that have been derived in the Zeigler No. 3 mine by using roof bolts under extremely adverse roof conditions J with the thought that much better results could be obtained in other mines with more normal roof conditions by applying some of the practices that were developed in this mine. Some of the benefits that have been obtained in this mine, which will be shown in this paper, are: 1. Increased tonnage per man-shift at the face when roof bolts are used, as compared to the tonnage under similar conditions when conventional timbering methods were used. 2. Increased efficiency of roof bolting by giving the foremen a definite plan to follow. 3. Reduction in delays caused by failures of the trailing cables of loading, mining, and drilling machines. 4. Reduction in the number of accidents after roof bolting was adopted. Inasmuch as the success that followed roof bolting in this mine was obtained under one of the most treacherous roofs in the Middle West, it is reasonable to suppose that correspondingly better results could be obtained under more favorable roof conditions by using the same procedure.

Jan 1, 1952

By Martin D. Conyac

A mineral resource survey of rock types and geologic structures indicates that the Mt. Henry RARE II area has low potential for the discovery of metallic minerals. Potential for coal and geothermal resources is negligible. Essentially, the Mt. Henry RARE II area has had no claim-staking activity, nor has any mine been developed in it. SETTING Size and Location The 23,000-acre (9,308 ha) "1t. Henry RARE II area (No. 1-666) lies within the Kootenai National Forest approximately 36 mi (58 km) north of Libby, Montana, in the Purcell Mountain; of Lincoln County. Irregularly shaped, the area measures roughly 5-1/2 mi (8.9 km) north-south by 8 mi (12.9 km) Past-west, and lies about 1-1/2 mi (7.2 km) south of the Canadian border.

Jan 1, 1982

By J. F. Barkley

The work covered in this report was done to meet the requests from many Government agencies for information on alleviating sludge difficulties in No. 6 (Bunker C) fuel-oil storage tanks. Accumulated sludge at times caused serious loss in tank capacities; pumps became overloaded or lost suction; strainers often required very frequent cleaning; fuel-oil heaters in some instances became fouled and inefficient; and gobs of sludge that passed the strainers interfered with good combustion. The requests also included questions regarding the usefulness in general of oil "additives" for preventing sludge and the relative merits of the many trade-named additives being marketed. Realizing that preventing such difficulties would result in substantial savings to the Government, an investigation was begun with the limited funds avail-able. Although various claims are made for No. 6 fuel-oil additives other than preventing sludge, only an investigation as regards the storage tank-sludge problem has been possible.

Jan 1, 1955

By R. E. Morgan

This publication presents abstracts of articles and investigations pertaining to the utilization of fly ash. The terms "fly ash" and "flue. ash," as' used in most of the papers, refer to the ash from pulverized-coal firing collected by electrostatic precipitators or mechanical collectors. Several investigators do not define the material on which they report beyond calling it fly ash, but they probably refer to the fine material resulting from burning pulverized coal. A few of the papers report on investigations involving not only the use of fly ash but boiler slag as well. These can be identified by the title of the articles. Bibliographical information and the abstracts are arranged according to the date the papers were published, with the most recent listed first. With the continually increasing use of pulverized-coal firing, profitable disposal of the fly ash is becoming a problem of greater importance to many utility and industrial companies. Also, in recent years, the public demand for cleaner air, and the more highly efficient fly-ash collectors available have resulted in the collection of a greater percentage of the fly ash produced. The solution to better utilization of fly ash has, therefore, been the object of research for some years.

Jan 1, 1952

By M. E. Volin

The Smuggler is one of the mines in the Aspen district, located the central part of Pitkin County, Colo. It was first examined in July 1943 by C. R. Wilfloy, former mining engineer of the Bureau of Mines at Salt Lake City, Utah, in, company with the lessees, R. D. Rohlfing of Aspen and J. W. Vanderwilt of Denver. The purpose of this examination was to sample a mineralized breccia zone that appeared continuous along the contact between the Leadville and Weber formations. These preliminary samples showed that the zone contains low but significant amounts of lead and zinc and that the minerals are partly oxidized and thus not easily concentrated. The mine was examined again in May 1946 by the senior author and William Herron, one of the present lessees of the property. This examination reviewed the previous sampling and recommended investigations by the Bureau of Mines. Sampling and drilling investigations were conducted by the Bureau from October 1946 to February 1947 and again from August 1947 to April 1948. Aspen is the center of a famous mining district that produced over $102,000,000 in silver and lead ores from 1880 to 1918, when a dispute closed down the mines (fig. 1). All of the workings below the Cowenhoven tunnel in Smuggler Mountain and the lower Durant tunnel in Aspen Mountain have been flooded since that time. The Cowenhoven portal now is caved, and Smuggler Nos. 1 and 2 tunnels are the only accessible workings in Smuggler Mountain. The only operating mine is the Midnight, situated 4 miles south of town at an altitude of 9,700 feet.

Jan 1, 1950

By David Schlain

"IntroductionThe purpose of this investigation was to study the characteristics of the high-acid electrolytic manganese cell with the idea of fitting it into one of the flow sheets being worked out by the Metallurgical Division of the Bureau of Mines for the recovery of manganese from low-grade domestic ores.In construction, the high-acid cell 3/ differs from the low-acid type in that the cathode and anode compartments are separated by a diaphragm of relatively low porosity, such as alundum. This is necessary because in the high-acid cell the two electrolytes are circulated separately. The anolyte is 15 to 30 percent H2SO4. The catholyte consists of a solution of ammonium sulfate and manganese sulfate with a OH of 4 to 3. The only mixing of electrolytes is that resulting from flow through the diaphragms. In the low-acid cell the two electrolytes are not circulated separately and do not differ so widely in hydrogen-ion concentration. Hence, the canvas diaphragm is sufficient.During operation of the cell, manganese is deposited on the cathode, and sulfuric acid is produced in the anode compartments. Various other reactions take place in the cell. There is considerable decomposition of water; hydrogen is evolved at the cathode, and oxygen is liberated at the anode. When lead anodes are used, some hydrated oxides of manganese are formed at the anodes. The quantity of oxides formed is not as great as it is in the low-acid cell, because fewer Mn++ reach the vicinity of the anodes."

Jul 1, 1942

By Irving Hartmann

[The explosability of coal dusts has been the subject of many investigations studies have been conducted in laboratories, in galleries and in coal faire; of several countries to obtain information on the causes, development, and prevention of mine explosions. Early laboratory experiments on it American colas dealt with pressures developed in test bomb by explosions of dust clouds and with, the effects of gas in the dust atmosphere.5/ Later, the emphasis shafted to evaluation of the relative fleet flammability and the ignition temperatures of coal dusts.6/ Much worthwhile effort was devoted to the development of Laboratory apparatus and test procedures that gave good correlation with large-scale explosion tests in the Experimental cost mine. In recent years a number of special problems were studied, mostly with bituminous Pittsburgh coal dust]

Jan 1, 1954

By Paul M. Tyler

One of the best present-day yardsticks of the material welfare of a nation is its consumption of minerals, The United States, with only 7 percent of the world population, consumes 45 percent of the world wealth, pays the highest real wages, has the shortest working hours, and numbers the largest percentages of home owners among its population, and at the same time its per-capita consumption of minerals is far greater than that of any other nation. In 1937, British India, with roughly twice the population of the United States, used less than 2 percent as much lead, 4 percent as muck zinc, and 13 percent as much copper; even in Europe, which has three times our population and where war preparations have greatly expanded the normal needs of peaceful industries, the aggregate consumption of metals and industrial minerals other than lignite is less than the total for the United States alone. The march of civilization passed from the Stone Age to the Bronze Age before the dawn of history. It may be questioned whether man or monkey first threw stones at an enemy, but only man could have fashioned rough stones into weapons. Eoliths rudely shaped by apelike men are believed by archaeologists to have antedated by hundreds of thousands of years the existence of our own human ancestors. The primitive people that followed the retreating Ice Cap northward in early quaternary period - at least a million years ago - were fairly adept in the shaping of flints and even used a little copper. The Bronze Age, so-called, superseded the Stone Age when, around 8,000 B. C., the news spread that chunk s of natural copper could be pounded into better weapons or cutting implements than ever could be made by chipping stones. The Bronze Age gave place to the Iron Age about 1,000 B, C., and though students of modern history may speak of the Coal Age, the Petroleum Age, and the Automobile Age, and so on, these ages have all been crowded into a brief century and a half. The truth is that we still are in the Iron Age, unless perhaps we choose to call it the Age of Many Metals.

Jan 1, 1940

By A. W. Deurbrouck

This report describes the preparation characteristics of the significant coalbeds from which samples could be obtained in Webster County, W. Va. In 1964, approximately 825,000 tons of coal was produced in the county, of which 732,000 tons was mechanically cleaned in three preparation plants. The Sewell coal bed accounted for 94 percent of the coal produced. Twelve samples were collected from five coalbeds. Four of the samples would require upgrading to meet metallurgical requirements; two others of just over 8.0 percent ash would require some upgrading. In general the coalbed samples collected in the county were of medium-sulfur and medium-to low-ash content as received or after removal of the sink 1.58-specific-gravity material.

Jan 1, 1966

By S. P. Kinney, P. H. Royster, T. L. Joseph

"The study described in this paper, on the reactions in an iron blast furnace, is part of the investigation being conducted by the Bureau of Mines on combustion of coke and the reduction of iron oxides in the blast furnace. Previous study of the combustion zone of the iron blast furnace, by means of a series of as samples taken through the tuyeres across the hearths of 13 blast furnaces, showed that the combustion of the coke in the blast-furnace hearth is complete at a distance of 32 to 40 inches from the nose of the tuyere, measured horizontally toward the center of the furnace. The results of this previous work are sum¬marized in the curves shown in figure 1, where it will be noted that practically all of the oxygen disappears at a distance of approximately 30 inches from the nose of the tuyere.In order to determine the height at which oxygen is found in a vertical direction above the tuyeres - it had been suggested that the combustion zone turned upward near the tuyere and to obtain comparisons with the samples taken at the Bureau of Mines experimental6 (5-ton) blast-furnace at Minneapolis, the Bureau extended the gas sampling on a commercial furnace to a number of planes between the tuyere level and the stock line. The sampling was conducted on a 300-ton furnace, making foundry iron, operated by the Central Iron and Coal Co., at Holt, Ala. The furnace was smelting Southern red and brown ores and nodules from pyrite sinter. Figure 3 is a vertical section of the furnace showing the six planes sampled."

Apr 1, 1926

By W. W. Adams

The United States Bureau of Mines, in cooperation with the National Send and Gravel Association conducted a safety contest in 1929 Among producers of sand and gravel. Only 26 plants were enrolled, as the contest was late getting under way. It is hoped that a ranch larger number of plants will be represented in the safety competition of 1930. Two trophies, both of which were provided by Rock Products magazine, were awarded at the end of the contest; one trophy was given for the best safety record among plants working 100,000 or mare man-hours during the year and the other for the beat record among plants working less than 100,000 man-hours. The trophies were presented to representatives of the winning, companies on January 29, 1930, at the annual convention of the National Sand and Gravel Association at Memphis, Tenn.

Jan 1, 1930

By L. C. IlsLey

The increasing use of Diesel engines for operating equipment on trunk-line railroads and for power-plant units has stimulated interest in the use of Diesel engines for other lines of work, among which is the possibility of substituting Diesel locomotives for trolley locomotives for mines. The possibility of developing Diesel locomotives for duty in American mines is not as remote as it might seem, particularly in view of the fact that locomotives of this type are already used in considerable numbers in European mines. A study of Diesel locomotives in Europe is contained in Report of Investigations 3320, Diesel Mine Locomotives - Development and Use in European Coal Mines, by George S. Rice and F. E. Harris.

Jan 1, 1938

By Carlton E. Brown

Inquiries and instructional work on the determination of the number concentration of dust in atmospheres known or suspected to contain pneumoconiosis (silicosis and asbestosis) - producing particulate matter indicate a need for a description of the impinger method used by the Bureau of Mines. The impinger method consists of the collection of dust in a liquid medium and the counting under the microscope of the particles in a known portion of this liquid. The dust-collecting device is called an impinger. The dust in the air drawn through this collector at a known rate impinges at high velocity upon a smooth surface under a bubbling column of liquid. The dust is either picked up from this surface by the liquid or removed from the air as it passes through the liquid.

Jan 1, 1938

By D. Harrington

The desirability of efficient control of air currents, and the necessity of supplying metal-mine workers with better and safer working conditions, has created an active interest in metal-mine ventilation, especially in recent years. This paper discusses the subject both with regard to efficiency and economy, as well as safety and health. It is based on personal observations of the writer from over four year's study of metal mines in six States, in which more than 50 mines were visited. Many of these were studied in detail; in all several thousand working places were examined, and readings taken relative to ventilation run into the tens of thousands.Object of ventilating metal mines:Whereas in coal mines ventilation is generally regarded as essential, in many metal mines, especially shallow ones, the operators pay little attention to ventilation, or ignore it altogether. Recent shortage of labor, and numerous accidents to which State compensation laws have directed attention, are causing metal-mine operators to regard ventilation more seriously, especially in deep, large mines.There is, in fact, greater necessity for adequate ventilation of metal mines than of coal mines. The latter require air currents to remove explosive gases and the fumes of explosives, but metal mines, in addition to the need of removing fumes of explosives, and occasionally explosive gases, frequently have need of removing dusts dangerous to health, reduction of high temperatures and high humidity, and removal of inert but unhealthful gases like CO2 and nitrugen. The generally accepted superior healthfulness of coal miners as compared with metal miners, is probably due in large part to the better air circulation in working places of coal mines.

Jun 1, 1920

By Will H. Coghill, I. L. Feld, G. D. Coe

The object of this paper . is to make known the superior classification accomplished in a hydraulic classifier designed to make use of principles determined by recent research ... The details of the design , the results of preliminary research , and the final testing are given . The classifier of the new design shown in figure 1 and another one like it are in operation as concentration classifiers in a Birmingham iron- ore mill recovering 4 tons per hour of concentrates from table middling that ` otherwise would require regrinding and retabling . The four factors that contribute to the successful operation of these classifiers are ( 1 ) a teeter column of small diameter , ( 2 ) use of an open - bottom tooter column classifier with a periodic pincer instead of the usual type , which terminates in a vortex, ( 3 ) a sorting chamber under separate hydraulic control , and ( 4 ) a teeter column of more than the usual depth . · At the outset it must be stated positively what the authors mean by hydraulic classification : They mean the reconstruction of a multimineral ground product into fractions graded with respect to size , so that cach fraction has the heavy mineral segregated in the fine sizes and the light mineral segregated in the coarse sizes . This definition presupposes that in multiplespigot classification the low specific gravity minerals are carried beyond the first cells to the later ones . The reader must take into account that , from the standpoint of classification , " ores " may be divided into two types , represented - by the following : ( 1 ) Joplin flint - blende ores , which , because of the hardness of the flint and the softness of the blonde , yield upon comminution a product that already has the essence of classification ; and ( 2 ) Birmingham Big Seam iron oros , which contain " easily shelled - out " sca sand and , upon reduction to about 10 mesh , yield a heterogeneous mixture in which the size analyses of the respective " floats " and " sinks " arc almost identical .

Dec 1, 1945

By S. L. May

Procedures for separating columbium and tantalum have been developed by the Bureau of Mines as part of a broad research program on the utilization of low-grade ores of columbium and tantalum, Columbium and tantalum compounds of greater than 99 percent purity have been obtained by application of the solvent extraction separation system: Hydrofluoric acid-sulfuric acid-methyl iso-butyl ketone. This system is unique in that it not only separates columbium from tantalum, but also separates these two metals from other metallic impurities. The system is effective for separating the metals irrespective of the tantalum and columbium ratio of the starting materials. Investigations in which the spent feed obtained from the initial coextraction step was recycled to the system indicated that efficiency was increased, and cost was reduced without impairing product purity. Continuous tests demonstrated that this solvent extraction system could be used in large-scale equipment without loss in efficiency or in purity of products. The separation of columbium and tantalum has been difficult because of the similarity in their chemical bahavior. Many methods have been proposed for separating these two elements, but most methods either did not achieve satisfactory separation or were tedious and time consuming. The Marignac process (3, 4)4 developed in 1866 was the only method used commercially until recently. This separation procedure is based on the difference in solubility in aqueous solution of potassium tantalum fluoride and potassium columbium oxyfluoride. Current commercial practice appears to favor solvent extraction as a method for separating tantalum from columbium (1). Several efficient methods for separating columbium from tantalum by solvent extraction (2, 9, 8) were reported earlier from this laboratory.

Jan 1, 1961

By Scott W. Hazen

METHODS of determining the grade and tonnage in a mineral deposit have not kept pace with scientific developments in certain other fields. The most commonly used methods of computing ore reserves and grade based on diamond-core-drill sampling are the cross section, the polygon, and the triangle. Tonnage and grade may be determined by these methods with acceptable accuracy, providing a sufficient number of samples is obtained; however, there is no means of determining when an adequate number has been taken or conversely if the deposit has been sampled excessively. It is demonstrated that, by using the techniques of statistical analysis, a mining engineer will be able to determine when a sufficient number of samples has been taken to determine the grade of a mineral deposit within a specified degree of confidence. Using statistical analysis to compute the estimated average grade of the ore makes it possible to compute a fiducial interval, when a distribution of the sample means is normally distributed, so that there is 95-percent confidence in the statement that the true average grade of the deposit is covered by the interval. This report utilizes data obtained from the Maggie Canyon manganese deposit, Artillery Mountains region, Mohave County, Ariz. Four separate exploration projects were conducted at Maggie Canyon between 1936 and 1950. Present economic conditions have made it desirable to determine the amount of 5-percent manganese ore developed by these projects.

Jan 1, 1957