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By Mark Sheppard

This paper is the second of a series recording the results of tests made at various quarries throughout the United States to determine, (1) the relation between the size gradation of feed to, and product from, primary crushers; (2) the particle shape of crushed product; (3) the differences in gradation and particle shape produced by different tries of primary crushers; and ( 4) the differences in gradation and particle shape caused by crushing different kinds of stone. Primary crushing has received comparatively little attention in the technical literature in spite of tine fact that the design of the whole crushing plant should be correlated to the performance of the primary crusher.

Jan 1, 1938

By R. W. Dougherty

From time to time interest has been evidenced in transporting coal with water in pipe lines. About the year 1895, United States patents broadly covering a method of pumping coal with water through pipelines were granted to W. C. Andrews. His process was used to some extent in pumping anthracite culm and waste back into the worked-out portions of the mines. About 1905, W. T. Donnely was granted patents relating to pumping anthracite silt away from the breakers. From about 1913 until 1924, a British engineer, Gilbert G. Bell, used a short pipeline to convey coal with water from barges on the Thames River to the Hammersmith Electricity Generating Station, London. Minus 5-inch coal was transferred 660 yards through an 8-inch pipe. Some trouble was experienced with fine coal, which tended to plug the line. Bell made several proposals to transport coal by pipeline overland from the Midlands to London, a distance of about 100 miles, but these were never adopted. This survey is concerned mainly with the problems presented by actual pipeline transportation of coal with water. It is assumed that the coal will have been processed to remove most of the abrasive impurities by conventional methods prior to introduction into the line, and that it has been crushed to the required top size. Dewatering at the discharge end of the line is considered part of the conventional cleaning process. There still remain many pump-performance and behavior of water-coal mixture problems that can be solved only by actual performance tests. It is recognized that the distribution of coal to other than very large users is not changed. Large storage areas would be required to supply seasonal markets. Large users, such as power plants and heavy industries, could be supplied by branch lines directly to the point of use, It is also recognized that pipe lines might not be able to carry a full range of sized coal to meet market demands in many areas.

Jan 1, 1951

By Paul Hatmaker

Diatomite is the name now generally given to a mineral substance composed of the tiny , skeletal remains of diatoms , which are microscopic , flowerless , water plants related to the algae ... This residuum is essentially hydrous amorphous silica. Common names for diatomite are : Diatomaceous earth , tripolite , kieselguhr , and infusorial earth . Strictly speaking , however , the latter material is not diatomite , as it is composed of the fossil remains of infusoria , which usually do not occur with the diatomaceae . Other synonyms for diatomite are : Diatomaceous silica , kieselmehl , bergmehl , diatomeenpeelite , polirschiefer , moler , molera , molererde , de smid earth , fossil flour , mountain flour , farine fossil , white peat , radiolarian earth , chalk rock, ceyssatite , randanite , and tellurine ; also various diatomite products of individual companies are known by their own trade names . Diatomite should not be confused with fuller's earth , for the two are separate and distinct substances . Bentonite , pumice , and tripoli , have also been used erroneously to designate diatomite . Tripolite , however , is a true diatomite formerly mined near Tripoli ..

Feb 1, 1931

By B. W. Jong

As part of the Bureau of Mines program to develop substitutes for critical and strategic materials for metallurgical applications, the Tuscaloosa Research Center has evaluated the effect of additives and starting materials on the sintering and strength properties of sialon (silicon-aluminum-oxynitride) compositions fabricated by conventional pressing and sintering techniques. Sintering and MOR (modulus of rupture) data were developed for sialon compositions produced from three components, Si3N4, A1203, and AIN. When doped with Y203 to aid in sintering, the highest MOR values were obtained with compositions containing between 20 and 30 mole-pet (A1203 + AIN). The effect of the crystalline phase of the Si3N4 and Al203 used in the three-component system on MOR also was investigated. Alpha-Si3N4 and ?-A1203 were found to be the best starting materials. A sialon composed of 67.4 mole-pct a-Si3N4 plus 32.6 mole-pct (?-AI203 + AIN), doped with 5 wt pct Y203, had MOR values at 25°, 1,200°, and 1,400° C of 40,300, 40,300, and 31,100 psi, respectively. Samples of this composition doped with Gd203, MgO, Zr02, and ZrSi04 also were evaluated. The ZrSi04-doped sialon had higher MOR values than Gd203-, MgO-, and Zr02-doped materials but lower MOR values than the Y203-doped sialon. The MOR values of ZrSi04-doped sialons were 25,000 and 25,900 psi, respectively, at 25° and 1,400° C.

Jan 1, 1981

By L. C. IlsLey

Through the cooperation of the Pennsylvania Department of Mines the writer obtained from State, records detailed information concerning coal-mine accidents occurring in Pennsylvania bituminous mines during 1939, particularly those nonfatal accidents in which the injured person lost 60 or more days? time from mark. The writer wishes to acknowledge assistance received from Pennsylvania State officials, especially Richard Maize, secretary of mines, and. Joseph J, Walsh, deputy secretary of mines; also to Thomas Dickinson,3/ of the Bureau of Mines, who rendered valuable assistance in assembling the data an the several tables.

Jan 1, 1941

By Frank J. Wiebelt

As a result of the examination of many copper-zinc properties in the West Belt area of California, nine were chosen for exploration projects by the Bureau of Mines. This was part of the Bureau's wartime mineral-development program aimed at maintaining production of essential metals and increasing ore reserves. The properties explored were the El Dorado, El Dorado County; Copper Hill, Newton, and Gray House, Amador County; Constellation, North Keystone, and Collier, Calaveras County; and American Eagle and Akoz, Mariposa County. In addition to surface sampling and mapping, 41 holes, aggregating 18,134 linear feet, were diamond-drilled. Detailed results of the work done on all properties except the El Dorado and Akoz are given in this report. The El Dorado and Akoz were discussed in Reports of Investigations 3896 and 4144, respectively. Figure 1 is an index map showing the location of the mines covered in this publication.

Jan 1, 1951

By K. C. Dean

During the investigations of the occurrence of manganese in the Western United States, a Bureau of Mines examining engineer collected samples frame two properties in Beaver County, Utah. As the ores were too low in grade to be acceptable by manufacturers of ferromanganese, beneficiation studies were made to determine the amenability of the ores to concentration. The Steelville property is about 37 miles southwest of Frisco, Utah. The deposit is an example of manganese occurring as a replacement of limestone in a bedded vein or as layers in limestone associated with shale and rock decomposition products. The Susie Q deposit, about 33 miles southwest of Milford, Utah, is also a tabular replacement deposit in limestone, apparently of limited extent. Test work was done on representative samples of 2-ton lots obtained by the examining 'engineer from each of the properties mentioned.

Jan 1, 1951

By B. K. Shibler, I. S. Solet, H. W. St. Clair

"This study was undertaken to provide a more adequate knowledge of the chemistry of the sulfide volatilization process for recovery of tin from low-grade Bolivian ores. The investigation was partly supported by the Department of State under its program for scientific cooperation with South American republics.The results of this investigation demonstrate the conditions under which cassiterite (Sn02) may be converted to stannous sulfide by reaction with pyrite or sulfur vapor. Quantitative data are given on the rate of sulfidization and on the vapor pressure of stannous sulfide.INTRODUCTIONAlthough the United States is the world's largest consumer of tin, virtually no tin ores occur within our national borders. Most of the world's tin supply comes from alluvial deposits in the Far East and in Africa, The major sources of tin ores are Malaya, Indochina, Bolivia, Belgian Congo, Nigeria, Thailand, Burma, China, and the United Kingdom. Bolivia is the only important source of tin in the western hemisphere. It was the chief source of tin f or the United States during World War II. The Government-owned tin smelter at Texas City, Tex., was built primarily for smelting Bolivian ores and depends largely on Bolivian ores for its operation. Bolivia is the only major tin-producing country in which the tin ores occur as vein or lode deposits requiring underground mining. Most of the tin from the Far East and Africa is mined by dredges from alluvial or placer depos its. It is recovered as a high-grade concentrate of cassiterite relatively free from impurities. The tin minerals in the lode deposits are more intimately associated with other minerals and more difficult to separate into a clean concentrate. Furthermore, a large part of the tin in the original ore is lost during concentration. The ores as mined contain only a few percent of tin, so they must be milled to separate the gangue minerals and produce a concentrate containing 30 to 40 percent tin before they are shipped to the smelter. The losses of tin that occur during milling vary from 18 to 65 percent. The average recovery of tin from Bolivian ores is probably 50 to 60 percent."

Dec 1, 1954

By C. A. Komar

The Bureau of Mines has undertaken an investigation to determine possible applications of acoustic energy at sonic and ultrasonic frequencies to improve ultimate recovery from oil reservoirs. A literature search was conducted to provide background information for initiating laboratory research. The purpose of the literature search was to review the uses that have been made of acoustic energy in the petroleum industry and to select procedures and techniques that could be applied to the solution of petroleum production problems. The characteristics (68)3 of ultrasonic energy make it potentially useful to a variety of industrial and experimental applications. Pulse techniques (99) are common in the testing of materials where inspection is accomplished by propagating an ultrasonic pulse through the material. Viscosity measurements (45) are made by interpreting changes in the absorption of sound as it is propagated through a flowing liquid. Cavitation phenomena (93) produced by high-intensity ultrasound in liquids have been used extensively in industrial cleaning, machining, impact grinding, and aluminum soldering operations.

Jan 1, 1963

By L. R. Burdick

Sulfur compounds have long been recognized as damaging pollutants of the air. A number of investigations have been made to determine the amount of such compounds existing in the air of various cities; moreover, some study has been given to the conditions affecting the concentrations. This paper summarizes published investigation and includes a bibliography on the subject. The methods of obtaining data have differed to the type of sampling, analysis procedure, hour of sampling, number of locations, and number of determinations made. Sampling methods include both the continuous type, covering a day or a number of days, and what can considered the ?snap? type, covering very short periods. Continuous sampling has, given data representing the average concentration at the location chosen but no information regarding variations from hour to hour, are none that might be said to represent the average for a city. The snap-sampling method, while not giving a true average for any one location or area, has in some instances made available date regarding variations of concentration during different hours of the day and at various locations or zones within the area chosen. Although the sulfur compounds in the air nay include sulfur dioxide, sulfur trioxide, hydrogen sulfide, and organic compounds of sulfur, most investigators report on the basis of sulfur dioxide. This gas unites with moisture to form sulfurous acid.

Jan 1, 1939

By T. E. Swigart

In connection with experimental work by the Bureau of Mines to determine effects of back pressure . on oil wells * , data were compiled on the engineering conditions in the oil field selected , in order to afford a more complete understanding of the wells tested , and to illustrate the extent to which underground conditions should be studied when making oil -field experiments of this nature . This report , containing the data mentioned, may be of interest to the oil industry , as it describes briefly the methods of operation employed in developing and exploiting shallow well territory .

Feb 1, 1923

By H. D. Baylor

This is the first of a series of papers describing mining methods and costs at cement plant quarries throughout the United States and deals directly with those methods employed and costs obtained at the quarry of the Louisville Cement Co. located at Speed, Ind. ACKNOWLEDGMENTS The author wishes to acknowledge the assistance of Mr. J. M. Buohheit, superintendent of quarries, and Mr. H. E. Schoonover, quarry engineer, in furnishing data and in compiling this report.

Jan 1, 1930

By J. H. Field

Results of studies by the Federal Bureau of Mines on a pilot-plant scale for removing hydrogen sulfide and carbonyl sulfide from gas mixtures by the hot carbonate system are given in this publication. Gases containing up to 10 pet. hydrogen sulfide and 48 grains carbonyl sulfide per 100 cu.ft. were treated. In most tests carbon dioxide also was present and was removed simultaneously with the sulfur compounds. Because the rate of absorption of hydrogen sulfide is much more rapid than that of carbon dioxide over a wide temperature range, selective removal of hydrogen sulfide occurred in the bottom section of the absorber near the point of gas entry. Hydrogen sulfide was removed to pipeline specifications with carbonate solutions by using split-stream flows in the absorber and regenerator.

Jan 1, 1960

By Mark Sheppard

This p aver is the second of a series recording the results of tests made at various quarries throughout the United States to determine, (1) the relation between the size gradation of feed to, and product from, primary crushers; (2) the particle shape of crushed product; (3) the differences in gradation and particle shape produced by different types of primary crushers; and (4) the differences in gradation and particle shape caused by crushing different kinds of stone. Primary crushing has received comparatively little attention in the technical literature in spite of the fact that the design of the whole crushing plant should be correlated to the performance of the primary crusher.

Jan 1, 1938

By Roger J. Morrell

Disk-cutter experiments were performed on five rock types ranging in compressive strength from 9,000 psi to 27,000 psi. A specially constructed testing machine called a linear-cutter apparatus (LCA) was designed to load and traverse a free-rolling disk cutter across a sawed rock surface. The LCA was instrumented to measure the vertical and horizontal forces acting on the cutter during the run.. The ability of disk cutters to fragment rock was determined for both 60--degree and 90-degree cutting-edge angles, and relationships and regression equations were developed to predict cutter performance based on rock physical properties and applied forces,

Jan 1, 1970

Maps To Accompany Bulletin 494

Jan 1, 1950

By Louis A. Panek

Roof bolting has been known for many years, although the practice had very limited application before 1948. Since then, bolting has been introduced as a systematic method of support in more than 700 coal mines and more than 200 noncoalmines and other underground openings in rock. By far the greatest number of bolts are used to support bedded roof. This is largely because of their use in coal mines, although roof bolts are used in mining bedded deposits of all kinds -potash (New Mexico), trona (Wyoming), and ores of iron (Alabama), lead (Missouri), uranium (Utah), lead-zinc (Utah), and copper (Michigan and Arizona). Thus, bolting has been successfully employed to reinforce bedded roof under a wide range of conditions despite the limited knowledge of the principles involved. This report develops the basic principles of bolting bedded roof based on elementary beam theory and on the results of tests intended to prove or disprove certain fundamental premises. Specifically, the objectives were to gain an understanding of the function of the bolts and the behavior of bolted roof and to establish standard bolt patterns. A combination of theoretical and experimental analysis was employed. The experimental method consisted of testing mine -roof models in a centrifuge. The models, the test procedure, and the model-prototype relations are described in a companion report (1)2/. A second companion report presents a method for designing systems of vertical bolts to reinforce bedded roof (2).

Jan 1, 1956

By Henry E. Blake

Defluorination studies on refractory fluoride - bearing compounds and minerals , particularly on partly defluorinated residues from high - temperature pyrohydrolysis , required a dependable and reasonably accurate analyticalcontrol method for the analysis of fluorine . The difficulty in liberating fluorine from the fluorides of metallic elements such as aluminum, zirconium , and rare earths by steam- distillation can be largely overcome if the distillation is made from a sulfuric - phosphoric acid solution of a sodium carbonate fusion of the sample material and if the distillation temperature is maintained at about 155 ° C. The data presented in this paper show that liberation of fluorine by this method is more complete and proceeds more rapidly than by usual distillations from perchloric or sulfuric acid alone or a mixture of phosphoric and perchloric acids . Fluorine in amounts ranging up to about 140 mg can be recovered by collecting only about 300 ml of distillate . Determination of fluoride in the distillate is made by the usual thorium nitrate titration .

Jan 1, 1963

By R. P. Beyer

[The Bureau of Mines has measured the low-temperature heat capacities and high-temperature enthalpies of crystalline K2Si2O5 as part of a program for advancing mineral resources technology with energy economy. High-temperature enthalpies of glassy and liquid K2Si2O5 and crystalline K2SiO3 were also mea¬sured. An adiabatic calorimeter operating over the range 5 to 308 K was used for the heat capacity measurements for K2Si2O5 from which the standard entropy at 298.15 K, S°298 = 45.55 ±0.05 cal/deg-mole, was calculated. Tabulated values of Cp°, S°, -(G° -HO°)/T, and H°-HO° from 5 to 300 K are given for K2Si2O5. A copper-block drop calorimeter was used in the enthalpy measurements, operating from 298.15 to 1,198 K for K2SiO3 and from 298.15 to 1,453.8 K for K2Si2O5. No transitions were found for K2SiO3. The KI2Si2O5 showed two reversible first order transitions, one at 510 K with a heat of transition of 0.29 kcal/mole and one at 867 K with a heat of transition of 0.38 kcal/mole. The heat of fusion for K2Si2O5 20 5 was calculated to be 8.42 kcal/mole. Relative enthalpies are given in equation form, and high-temperature values are tabulated for Cp°, S°, - (G°-H°298 )/T, and H°-H°298 . Also tabulated are ?H°, ?G°, and log K for formation of K2SiO3 and K2Si2O5 from both the elements and the oxides.]

Jan 1, 1979

By A. W. Fahrenwald

The purpose of screening is to separate a crushed or natural product into one or more products in which size of grain is constant, or within certain size limits. The ore dresser finds need for this operation in the laboratory, in the study of ore-dressing processes, and for various purposes in the plants. In the plant, for example, screens are employed in closed circuit with crushing devices such as rolls, and sometimes are used in closed circuit with ball mills. Screens are generally used to prepare jig feed where a sized feed is wanted. For any given sieve opening there is in any feed a certain percentage of grains that will pass through the sieve meshes only with difficulty and under favorable conditions. For example, cylindrical grains of length greater than the maximum dimension of the sieve mesh and of diameter less than the sieve opening pass the sieve only when the long axis of the grain is normal or nearly normal to the sieve. Whether such grains should actually be in the through's or the oversize of a screening operation--considered from the point of view of the subsequent treatment of the grains--can not be said. The grains that pass the sieve opening in a screening process only under-favorable conditions have been named "difficult" grains by R. K. Warner.4 In many ore-dressing flow-sheets it probably matters little whether these difficult grains show up in the screen through's or oversize. The main objection to them is that they are sieve-blinding.

Jan 1, 1929