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By Joseph Grumer

About a century ago Bunsen and his associates invented the famous burner that bears his name and was to become the ancestor of today's gas appliances. Over the years, Bunsen's invention became the starting point of a highly developed, practical technology that culminated in the gas industry as we now know it. However, it did not occur to the early workers to investigate the scientific potentialities of the new device, and as a result the science of gas-burner performance did not keep pace with the growing industry. It was with the objective of closing the rapidly widening gap between science and technology that the present research was undertaken Its immediate purpose was to provide basic information on the combustion characteristics of .fuel gases, in particular as they affect flashback, blowoff, and yellow tipping. Information obtained in the present research and contained within this report consists of the following: (1) Fundamental flashback and blowoff characteristics have been determined, it is believed, for all fuel-gas mixtures in which the gas industry may be interested. These are critical boundary velocity gradients for flames in free air, on burners with ports at room temperature and pressure. Burner aeration is characterized by the parameter, fraction of stoichiometric. These basic limits are explained, values are presented, and calculation procedure is given for deriving corresponding values of port loading and percent primary air (chs. I and II).

Jan 1, 1956

By G. B. Shea

"In 1928, there were 47 fatal accidents in the California petroleum industry, 14.6 per cent more than occurred in 1927 when 41 men lost their lives in the drilling, producing, manufacturing, and marketing divisions of the industry. This increase in the number of fatal accidents for 1928 has caused the first upward trend in the fatality curve of the California petroleum industry since 1923. In no other year during the 6-year period have the fatalities in any one year been greater than those for the preceding year. This fact should be given serious consideration and study by the petroleum industry, and an endeavor should be made to cause the number of fatalities again to decrease and conform to the previous gradual declining trend of the fatality curve.The following chart shows the trend of fatal accidents during the past six years:Of the 47 fatalities in 1928, 30 occurred in the drilling and producing division, 1 in the pipe line and transportation division, 14 in the refining division, and 2 in the sales and marketing division. A comparison of the number of fatalities in each division for 1927, and 1928, is given in the following table:3"

Sep 1, 1929

By James S. Browning

Recovery of fine mica from a sample of impounded tailing from the Dixie Mines, Inc., crushing and screening operations, Heflin, Ala., was investigated to determine if plant losses of mica could be reduced while econmically producing a commercially acceptable mica concentrate. Conventional wet-tabling and agglomerate-tabling methods yielded concentrates assaying about 95 percent mica from the tailing that contained 17 percent mica. Products containing about 98 percent mica and accounting for mica recoveries of 86 percent were obtained by flotation, using as reagents sulfuric acid, kerosene, and coco amine acetate (a mixture consisting chiefly of dodecyl and tetradecyl amine acetates). The results of the batch flotation tests were verified by tests in a small continuous flotation pilot plant.

Jan 1, 1963

By James W. Martin

This user's manual analyzes the application, selection and performance of front-end loaders in mining operations which can effectively utilize their load-and-carry capability. All aspects of the application are considered starting with a discussion of the load-and-carry system and alternate material handling methods. Site conditions such as the geology of the formation, material characterisitics, alternative mine plans and working conditions are identified. Selection considerations include machine design characteristics, production capabilities and ownership and operating costs. Typical operating practices and safety procedures are discussed. Comprehensive machine specifications, together with a series of checklists and worksheets, are included for preliminary analysis.

Jan 1, 1981

6889. Aslakson, C. I., and Swick, C. H. Gravity Observations in Peru and Colombia. Coast and Geodetic Survey,-Special Pub. 233, U. S. Government Printing Office, Washington, D. C., 1943, 18 pp. (Price, 10 cents.) In accordance with the policy of cooperation among American republics, the-United States Coast and Geodetic Survey in 1941 made gravity surveys in Peru and-Colombia. The information was desirable for determining the figure of the earth for geophysical purposes and for studying the relationship between intensities of gravity and deflections of the vertical. The survey instrument was the Brown pendulum apparatus. 11 gravity stations were established in Peru and 13 in Colombia. The results obtained at these stations are given in a table covering observed gravity, theoretical gravity, and anamalies. - V. S.

Jan 1, 1943

By William O. Vanderburg

This report3/ gives the reconnaissance of a reconnaissance of the mining districts in Churchill County, Nev., made in the fall of 1938 and spring of 1938 All of the mining districts in the county were visited, but no attempt has been made to include all the mines and prospects within the area; inclusion or omission of a property in this paper has no bearing on its merits, The report gives the situation of the various districts, mineral production, and ownership of properties; describes the ore deposit, mines, and prospects; contains information on past and current activity; and includes other data likely to be useful to those interested in the development of our mineral resources. The various district, were named when they were organized for purposes of record and regulation. When established, the districts embraced large areas n without well- defined borders, so that the names have little geographical significance.

Jan 1, 1940

By Robert W. Thomas

This paper describing the mining practices at the Ray mines at Ray, Arizona, is one of a series being prepared by the Bureau of Mines on mining practices, method and costs in the various mining districts of the United States. At the present time (1929) all mineral Production of the Ray district comes from the Ray Mines of the Nevada Consolidated Copper Co. The ore body is being worked from two shafts, designated as No. 1 and No. 2. An undercut block-caving method of mining is used, variations of which are employed to fit different conditions. The present method has been developed by making improvements as experience was gained or when conditions changed. Refinements in practice are continually being made. The Ray mine was the first in the Southwest to use a caving system of mining on a large scale.

Jan 1, 1929

By W. W. Agey

As a part of the program of investigation of domestic sources of manganese in the western United States, engineers of the Bureau of Mines examined. and obtained samples of ore from two properties in the vicinity of Barstow, San Bernardino County, Calif. In addition to these, samples from two other properties in the same vicinity were submitted by the owners. As the ores were too low-grade to be acceptable for the direct production of ferromanganese, beneficiation studies were made to determine the amenability of the ores to concentration by ore dressing. The Big Reef manganese claims axe about 140 miles east of Barstow, Calif. The claims were leased by W., E. Thurber of San Gabriel, Calif., from the owner, C. S. VanDoren of Daggett., Calif. Manganese oxides occur as a replacement deposit in heavily brecciated andesite along a fault plane. Four samples were taken by an examining engineer of the Bureau of Mines from the ore zone, which, when composited, were representative of all the exposed ore. Preliminary tests were made on lot B, and final tests wore made on the composite sample. The Trans-Oceanic property is about 20 miles southeast of Barstow, near Newberry, in the. Pisgah mining district, Calif. The sample, submitted by the owners, was taken from a 1,000-ton reject clump from a hand-sorting operation. The ore occurs as a replacement of rhyolite.

Jan 1, 1952

By H. Robert Ensminger

The Belizean economy registered a modest real growth of 1.3% during 1981. The gross domestic product (GDP), based on current prim was $121 million' with an inflation-rate of 10%. The country received $19 million in economic aid during 1981. In early 1981, Belize'e four commercial banks raised the interest on deposits to 15% in an effort to curb capital outflow. During 1981, the financial situation deteriorated somewhat, particularly the balance of payments. For the year the total value of imports exceeded exports by almost $38 million, while the Government continued to maintain a fairly free trade policy. Import duties and term averaged about 8% on essential item and 40% on nonessential ones.

Jan 1, 1983

By Thomas W. Camm

This study was done to evaluate the costs of various dumping operations at waste and spoil piles. It has been theorized that accidents associated with dumping operations might be reduced by short-dumping rather than edge-dumping, but many operators have been reluctant to use short-dumping because they believe it is not as cost effective as edge-dumping. To evaluate this perception, researchers at the Spokane Research Laboratory of the National Institute for Occupational Safety and Health reviewed the costs of various dumping methods at waste and spoil piles. The study found that overall cost differences between the two methods were not significant in most cases. However, while overall cost differences between the two methods appear small, capital costs could be more significant when short-dumping if numerous dump sites are used concurrently. The choice of which method to use should be based on considerations of the safety of dozer and truck operators.

Jan 1, 2000

By H. S. Auvil

[The shrinkage of coke after formation is one of the variables that effects the net expansion of the change in both industrial and test ovens. Various test results5/ have been interpreted as indicating that cokes from certain coals shrink to a marked extent and that other cokes show very little shrinkage; but no comprehensive experimental study of the shrinkage of coke after its formation and of the factors influencing this shrinkage has come to the attention of the authors.]

Jan 1, 1940

By Charles Janin

The recovery of gold from sands and gravels is one of the oldest forms of mining; it antedates history and has been practiced by savage peoples. In North America the search for placer gold has been a powerful agency in the exploration and development of unknown regions and has profoundly influenced the course of our civilization. With the progress of invention, the improvements in machinery, and the availability of large capital for the conduct of great operations, the tendency in placer, as in many other branches of mining, has been toward the working of extensive but comparatively low-grade deposits. The early miner washed the rich spots in stream beds or terraces with his pan, his long tom, and his primitive sluice. Then followed the growth of hydraulic mining and the use of giants supplied with water under pressures of hundreds of pounds to the square inch that could work at a profit gravels whose gold tenor was less than 3 cents to the cubic yard. Finally came the dredge that could handle deposits lying so far below water level as to be beyond attack by other methods. Although the gold dredge was first successful on a commercial scale in New Zealand, it has reached its present strength and efficiency in this country and its development is a monument to the daring, per- severance and technical skill of the many men, mine owners and engineers who have each contributed something to the final result. The Bureau of Mines, authorized to conduct investigations for the purpose of increasing efficiency in the mineral industries, had its attention called some years ago to the need of a comprehensive report on gold dredging in the United States. The director of the bureau recognized that such a report should summarize the development of the gold dredge, should describe in detail the essential features of present-day dredges, should discuss the facts that determine whether a placer deposit can be profitably dredged, and should point out the approved methods of prospecting placer ground and of operating dredges. At the request of the director, the author undertook the preparation of such a report and has been intermittently engaged on the task for several years. This bulletin is the outcome of his labors. He hopes that it will prove of interest to designers and builders of dredges, to mining engineers, and to persons who may contemplate investing capital in placer-mining ventures.

Jan 1, 1918

By Parry. V. F.

"SUMMARY This report reviews the status of the packaged-for industry as of 1941. A field study was made of 35 representative plants to obtain technics and economic data on different types of processes used to make packaged fuel in the Central States. The report includes a classification of processes, photographs of typical operations, designs of different plants, an analysis of costs of manufacture, and a study of the physical and chemical properties of fuel cubes.It was observed that many of the smaller plants were having troubles in the manufacture of packaged fuel as the price of materials and costs of labor advanced toward the higher levels of 1942. In some instances, the total cost of manufacture was as high as $5.00 per ton, while in the better, medium-sized plants it was approximately $3.25 per ton. The direct manufacturing costs, excluding investment and depreciation, ranged from $3.17 to $2.37. These costs permit almost no profit at small plants when packaged fuel sells for the same price as competing lump coal under conditions existing in 1941-42.It was found that the predominant troubles in plants were due to inadequate drying and insufficient mixing of the starch binder. It was ob¬served that in the better plants, where proper mixing of binder was attained high-quality packages were made if 50 to 70 percent of the moisture was removed in the drying ovens. Experimental data obtained in the laboratory show the relationship between the temperature of dry air and the time required to remove different percentages of moisture in wrapped orunwrapped coal cubes.The average physical and chemical properties of fuel cubes made by five processes are listed, and tentative standards for minimum physical qualities and methods for measuring quantity are giver."

Jun 1, 1944

By Candice Stevens

The Territory of Afars and Issas is to receive its independence from France on June 27, 1977. The Territory's economic income was based on entrepôt trade through the port of Djibouti and trans-shipment of goods on the Chemin de Fer Franco-Ethiopian (CFE) railroad. The Territorial budget was scheduled to in- crease from $32.6 million3 in 1976 to $36 million in 1977, despite severe shortfalls in 1976 stemming from inflation and a persistent balance-of-trade deficit. Subsidies from France continued to sustain the economy, and the French pledged to provide approximately $140 million in aid annually after independence. In 1976, financial agreements were concluded with a number of Arab oil-producing countries, including Saudi Arabia which granted $10 million toward development projects. The new Republic of Djibouti is scheduled to become the 49th member State of the Organization of African Unity (OAU) and the 21st member of the Arab League, and to receive aid from their financial institutions. The port of Djibouti and the CFE railroad constituted the Territory's main economic resources. Traffic at the port greatly

Jan 1, 1980

By L. C. IlsLey

Explosives have been fired electrically for several decades. Mountains have been tunneled, deep shafts sunk, extensive coal and metal mine workings excavated and, in times of war, railroads, buildings, bridges, and fortifications have been destroyed by means of electrically fired explosives. Modern engineering depends so much on explosives that their safe and efficient handling and especially their detonation are of prime importance to all those connected with the use of explosive agents. Electric shot-firing is only one method of igniting explosives, but it is rapidly spreading and because of certain inherent safety features should be encouraged. Data collected by the Bureau of Mines indicate that in the United States a large percentage of the blasting in quarries, shafts, and tunnels, and from 15 to 25 per cent of the blasts in mining operations, are set off electrically. The Bureau of Mines is interested in electric shot-firing because of its use in mining, and especially because electric methods, when properly applied, are undoubtedly safer than other methods commonly used.

Jan 1, 1926

By H. C. Fuller, J. H. Jacobs

"Manganese ore from Metals Reserve stock piles at Deming, N. Mex., Cushman, Ark., and Philipsburg, Mont., were processed in the Bureau of Mines pilot plant at Boulder City, Nev., to determine their suitability for the production of electrolytic manganese. Manganese was produced successfully from all of the ores.The ores, crushed and ground to minus 33-mesh, were roasted in a Skinner furnace to reduce the manganese and were then leached with spent electrolyte, from the cells, containing sulfuric acid. Acid-leach extractions of 96 percent on Deming, 89 percent on Cushman, and 97.5 percent on Philipsburg ores were obtained. Neutralization of leaches with ammonia results in the highest manganese extraction; but Cushman and Deming leaches could not be neutralized with ammonia, because the amount required was more than enough to maintain the proper ammonium sulfate concentration. A combination of ammonia and calcine was used. However, ammonia was satisfactory for neutralization of Philipsburg leaches. Sulfuric acid needed for make-up was as follows: Deming, 0.380 pound per pound of manganese extracted when neutralized with ammonia and calcine; Cashman, 0.402 pound per pound of manganese extracted when neutralized with ammonia and calcine; Philipsburg, 0.594 round per pound of manganese extracted when neutralized with ammonia alone.All of the leach slurries settled well enough to be separated and washed in countercurrent thickeners.Impurities were precipitated with hydrogen sulfide and removed by filtration. Cushman ore solution contained only- small amounts of impurities and required 0.055 gram of hydrogen sulfide per liter of solution for purification. Deming and Philipsburg solutions contained large amounts of zinc and required 0.55 and 0.65 gram of hydrogen sulfide per liter of solution, respectively.Electrodeposition was satisfactory on all three ores and current efficiencies of 62 to 66 were obtained.A process for the production of electrolytic manganese has been developed by the Bureau of Mines, first on a laboratory scale4/ and then on a semicommercial pilot-plant scale.5/ At first the- pilot plant operated on ore from the Three Kids mine near Las Vegas, Nev., to determine the practical features of the process on ore of this type. Since completing the work on this ore, the pilot plant has been used for processing other domestic ores to obtain engineering data and other economic information regarding the amenability of such ores to the process."

Sep 1, 1946

This manual provides instructions for installing, operating, and maintaining a protective canopy on the Galis Mfg. Co. face drill. The instructions are based upon an actual installation made in the mine on face drill model 460-S. The parts list and engineering drawings for the protective canopy are included at the end of the manual. And a discussion of some alternative design concepts is also included. The manual can also be used for retrofitting other face drills with similar protective canopies. Skilled mechanics can determine if the instructions herein would be applicable to the other face drills and can determine any necessary modifications if they are not.

Jan 1, 1973

By Paul G. Marinos, Vassilis Marinos, Evert Hoek

The Geological Strength Index (GSI) is a system of rock mass characterization that has been developed in engineering rock mechanics to meet the need for reliable input data related to rock mass properties required as input for numerical analysis or closed-form solutions for designing tunnels, slopes, or foundations in rocks. The geological character of the rock material, together with the visual assessment of the mass it forms, is used as a direct input for the selection of parameters for predicting rock mass strength and deformability. This approach enables a rock mass to be considered as a mechanical continuum without losing the influence that geology has on its mechanical properties. It also provides a field method for characterizing difficult-to-describe rock masses. Recommendations on the use of GSI are given and, in addition, cases where the GSI is not applicable are discussed.

Jan 5, 2007

By W. R. Hardwick

This paper describes open-pit mining methods and practices at Copper Cities Division of Miami Copper Co, in Gila County, Ariz. It is one of a series being prepared by the Burea of Mines on mining methods, practices, and costs in various mining districts of the United States. A similar program, conducted from 1928 to 1939, provided technological information on the development and conservation of our mineral resources and assisted operators and engineers in evaluating and developing new mineral deposits. This circular contains a brief history of the district and describes the Copper Cities deposit, with particular emphasis on a detailed description of those characteristics--physical, economic, or engineering--that affect the choice of mining method. Prospecting and exploration, sampling and estimation of tonnage and values, development, and mining (including breaking ground, loading, hauling, ore control, and auxiliary operations related to mining) are described, Percentage of extraction, production rate, safety, first aid, Eire prevention, mine organization, and processing plant are discussed briefly, The final section gives such costs, on a percentage basis, as are available for publication. Where relevant, some information on the Castle Dome mine is included.

Jan 1, 1960

By John C. Machisak

THIS CHAPTER of the Minerals Yearbook (Volume III) contains overall injury experience for coal mines, both anthracite and bituminous, coke plants, petroleum and natural gas, peat, and asphalt and related bitumens (native); metal mines, their metallurgical plants, including ore-dressing plants and primary nonferrous reduction plants and refineries; nonmetal mines; nonmetal mills; sand and gravel operations; slag (iron blast-furnace) plaints; and stone quarries and their related pants. Volume I of the yearbook contains a chapter showing injury experience and employment data treated separately by metal mines, nonmetal mines, quarries and their related plants, metallurgical plants (ore-dressing plants and primary nonferrous reduction plants and refineries are shown separately), nonmetal mills, sand and gravel plants, and iron blast-furnace slag plants. Volume II contains injury and employment experience in the fuel industries (coal, coke, petroleum and natural gas, asphalt and related bitumens (native), and peat. Injury and employment data are submitted voluntarily for the mineral operations through an industry canvass made by the Bureau of Mines, except for the coal industry, whose reports are mandatory. Information published in this chapter is the result of this canvass. Figures presented in this chapter for 1961 are preliminary except for anthracite, peat, coke, petroleum and natural gas, asphalt and related bitumens, and slag. These preliminary data, with the exception of bituminous coal, are a summation of reports received by May 31, 1962, from the operators showing their injury and employment experience. Estimations of injury and employment experience are not included in these preliminary data.

Jan 1, 1962