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By M. H. Kline

The Scarlet mine, in Randolph County, N. C., was operated on a small scale at intervals from 1899 to 1915, but no records of the quantity of ore produced are available. J. I. Moore unwatered the mine in March 1948, and Bureau of Mines' engineers examined the underground workings. Several assays checked previous sampling of the mine and indicated a small but comparatively high-grade copper-zinc deposit. The high metal content of the veins and the possibility of developing additional reserves prompted the Bureau of-Mines to drill three holes, totaling 530 feet, at the deposit during March and April 1948. Drilling disclosed that the mineralized vein did not extend over 300 feet along the strike and is probably limited in depth to the contact with the granite mylonite.

Jan 1, 1949

By D. L. Paulson

The Bureau of Mines studied the feasibility of producing copper matte in an electric furnace from blends of copper concentrate similar to those currently smelted in a gas-fired reverberatory system at an installation in Tacoma, Wash. A 800-kva electric-arc furnace was used to determine the distribution of constituents when arseniferous concentrates are being smelted in an electric-arc furnace. Test results from smelting 40 tons of materials indicated that electric smelting is more like a conventional gas-fired system than originally expected. Although gas composition over the molten bath is much different in an electric furnace, the secondary constituents such as arsenic, lead, zinc, and antimony behaved the same as in a reverberatory furnace. The results established that an electric furnace would be compatible with sulfur and particulate recovery facilities that are being used.

Jan 1, 1976

By McHenry Mosier

A skull breaker has demonstrated its advantages for secondary breaking in a limestone quarry by entirely displacing secondary blasting . It has reduced safety hazards to workmen, increased the number of quarry operating days , and has lowered mining costs by 2.7 cents a ton. It is believed that the application of the skull breaker can be made economically advantageous in the surface mining of other commoditics .

Aug 1, 1948

By Jos. R. Guiteras

This paper is one of o. series describing mining and milling methods and costs being published by the United States Bureau of Mines. It presents the results of a study of the Alice mine by the writer in December 1936. ACKNOWLEDGMENTS Acknowledgment is made to J. Fred Johnson, mining engineer off the American Smelting & Refining Co., for permission to visit the property; and to Arthur F. Johnson, general superintendent at the property, for his friendly cooperation in contributing the information contained in the paper.

Jan 1, 1939

By R. L. Marek

The number of persons fatally injured in the California petroleum industry in 1932 was 24, a decrease of 6, or 20 percent from the number killed in 1931. The decrease in the number of fatalities occurring in 1932 caused the fatality curve of the California petroleum industry to reach its lowest point in 10 years. Changing conditions in the oil industry - reduced personnel, decreased active field development, and curtailed production - have undoubtedly caused a part of this decrease, but continued accident-prevention efforts by the industry have also contributed to the reduction in the number of fatalities for 1932. The Bureau of Mines has analyzed and reported annually the fatalities in the California petroleum industry for a period of 10 years. Figure 1 shows the trend of fatal accidents during that period. Fatality statistics for 1932 show that the drilling and producing, pipe line and transportation, and refining and natural gasoline divisions of the industry had fewer accidents in 1932 than in 1931, sales and marketing being the only division that showed an increase over 1931. The number of fatalities by divisions for 1931 and 1932, percent of total, and percentages of increase and decrease are given in Table 1.

Jan 1, 1933

By Janke L. W. Jolly

Owing to an upsurge in export earnings. Cameroon made substantial economic Progress in 1978 and 1979. With a real growth estimated at 6%, the gross domestic product (GDP) for 1979 surpassed $5 billion.2 Crude petroleum production was providing a new potential in 1978 and 1979 for achieving national self-sufficiency. Among other benefits, crude petroleum exports were helping to offset the escalating costs of refined petroleum imports and to reduce the 14% to 17% annual rate of inflation. Over the 4 years prior to 1978, Cameroon's petroleum imports increased by 12.1% in volume annually, while the import cost increased by 24.5% annually to about $105 million. Total export earnings for 1978 were $805 million,3 to which crude petroleum contributed $25.3 million and crude aluminum product exports contributed $25.9 million. Petroleum exports had increased to about $240 million in 1979 and were in third place after coffee and cacao. Total imports for 1978 were valued at nearly $1 billion. The volume of petroleum imports decreased in 1979 to 552,000 tons, compared with 622,000 tons in 1978. The European Economic Community (EEC) countries purchased over 75% of total Cameroonian exports and provided most of the Nation's imports. The United States purchased $12.4 million in petroleum exports from Cameroon in 1978. Domestic consumption of aluminum metal from imported Guinean alumina continued. to grow; thus exports of this metal to France (valued at $2 million in 1978) and Japan

Jan 1, 1981

By Fred D. DeVaney

The Mesabi iron district of Minnesota has a potential production of over 50 million tons of iron ore annually. The large shipments of ore each year are gradually depleting the reserves, and if the present rate of production is to be maintained there must be a growth in the present available ore supply. Growth is a natural course. The growth of a city may be affected by the addition of city blocks or by the improvement of utilities necessary for its betterment. These may go on in the order named or concurrently. The city-block type of growth of the Mesabi has been tremendous, and the "betterment" type has followed in due course. Probably the former has reached its limit, and if so, more time will be allotted to the latter. It is not the intent of this paper to present either a eulogy of the wonderful mining methods or a history of the milling, but it is pertinent to say that if the lean-ore area continues to produce, the continuance will be more the result of further improvement of milling methods now well under way than of extension, of boundaries by the city block plan of growth. In an examination of the western end of the Mesabi district one finds sludge basins containing millions of tens of millable ore rejected by washing plants which were built for economy in operating cost and with little thought of conservation, and rich tailings piles of jigging plant rejects. In addition, there is an appreciable tonnage of bowl rake products so low-grade that it requires mixing with the best ore of the district to make it merchantable.

Jan 1, 1932

By H. R. Batchelder

The Bureau of Mines Gas Synthesis Demonstration Plant at Louisiana, Mo., includes apparatus for the gasification of pulverized coal with oxygen and superheated steam. A pebble heater constructed by the Babcock & Wilcox Co. is used to superheat nominal 5-pound steam for the gasification process, usually to temperatures of 1,600° to 2,300° F. with flow rates of 1,400 to 2,300 pounds per hour. Heaters of this sort have been described. So far as is known, the Babcock & Wilcox Co. is the sole commercial manufacturer of equipment of this type. Units have been built with capacities above 18,000 pounds of steam per hour.

Jan 1, 1951

By G. E. Johnson

A bench-scale study was made of removing hydrogen sulfide from synthesis gas at elevated pressure by iron oxide impregnated on wood chips. The gas contained 0.02 to 0.06 percent oxygen. The removal of hydrogen sulfide by iron oxide impregnated on wood chips is more efficient at elevated pressure. At constant space velocity, longer periods of operation at 400 p.s.i.g. are possible before the exit gas reaches a given maximum concentration of hydrogen sulfide, compared with 200 p.s.i.g. or atmospheric pressure. In tests at room temperature, 60° C., and 100° C., the most effective removal of hydrogen sulfide was obtained at room temperature and the least effective at 100° C. Dry impregnated wood chips removed only about half as much hydrogen sulfide as chips wetted to a water content of 50 percent.

Jan 1, 1962

By V. B. Dale

This paper is one of a Federal Bureau of Mines series covering the mineral resources of the Nation. It briefly describes most of the tungsten deposits in Cochise, Pima, and Santa Cruz Counties, Ariz. Most of the descriptions are from field examinations by the two senior writers, prior to July 1957. Wolframite first was identified in Arizona in 1896 by W. P. Blake, Territorial Geologist. Tungsten mining began about 1900 in the Little Dragoon deposits of Cochise County, and about 1901 in Las Guijas district of Pima County. The price history of tungsten is an erratic one; consequently, production has been erratic. Prices rise during wars and periods of national preparedness. Production of tungsten ore was stimulated greatly by a Government purchasing program, announced on May 10, 1951, wherein the Government agreed to purchase standard-grade tungsten concentrates at $63 per short ton unit5/ for 5 years or until 1,468,750 units were purchased. This was later increased to 3,000,000 units, and after this amount had been purchased in June 1956, the purchase of an additional 1,500,000 units was authorized. Government purchase, however, was suspended in December 1956 before completion of this latter program, and the price of tungsten concentrates declined sharply. The price had dropped to $15 per short ton unit, duty extra,6/ by the last part of July 1957.

Jan 1, 1960

By L. C. IlsLey, H. H. Clark

As part of its investigations of the causes of mine accidents and of the safest and most efficient methods of handling electricity underground, the Bureau of Mines undertook a study of the ignition of mine gases by the filaments of electric incandescent lamps. This bulletin describes the investigation in detail and gives a complete record of the results obtained.

Jan 1, 1913

By Christopher Mark, Anthony T. Iannacchione

Falls of ground continue to be one of the most serious causes of injury to U.S. miners. Of the 256 fatal injuries that occurred in mining between 1996 and 1998, 52 (20%) were caused by falls of ground (Table I). Falls of ground affect some sectors of the mining industry more severely than others. For instance, nearly 40% of the 98 coal mine fatalities between 1996 and 1998 were caused by falls of ground. Underground miners are at much greater risk than surface miners. Nearly half (45 out of 101) of underground mine fatalities were attributed to roof, rib and face falls, while less than 5% of the 155 surface fatalities were caused by falls of highwalls or slopes. Sources of Data All of the injury data examined in this study were derived from MSHA’s Fatal Investigation Reports (www.msha.gov)and the MSHA accident database. Because falls of ground often result in serious injury, MSHA Fatal Alert Bulletins and Fatal Investigation Reports provide a useful snapshot of ground control issues in the mining industry. MSHA requires that mines file a report on every reportable accident that occurs, containing information on the accident’s location, severity, classification, activity, and nature of injury, etc. A short narrative is generally included as well. Accident reports can be searched by many of the above fields. From 1996 to 1998, miners suffered a total of 55,096 injuries, which ranged in severity from death (degree 1) to injuries with no days away from work nor restricted duty (degree 6). Six percent of the total injuries were from falls of ground, including machine accidents where caving rock was coded as the source. As the data in Table II indicate, 98% of all non-fatal fall of ground injuries occurred in underground mines, with underground coal mines accounting for 83% of the total. Table II also shows the distribution non-fatal fall of ground injuries by severity and commodity. The injuries are classified into Lost Time Injuries that resulted in permanent disability (degree 2) or days off work (degrees 3-4), and Injuries Without Lost Time that resulted in no more than restricted duty (degree 5-6). Overall, groundfall injuries appear to be more serious than other types of mining injuries. 65% of all ground fall injuries resulted in lost time compared to 54% of all types of mining injuries.

By F. Fraas, H. H. Storch

"In the second paper 4 of this series, data were presented concerning the decomposi¬tion of polyhalite by saturated salt solutions. It was found that uncalcined polyhalite upon leaching with boiling saturated sodium chloride solutions yielded a brine in which the (K2 Mg) /304 ratio was considerably higher than that obtained from the calcined material, and for this reason appeared more suitable for the production of potassium chloride. It was found, in fact, that the leach liquors from uncalcined polyhalite deposited a mixture of KC1 and NaC1 upon evaporation and subsequent cooling, whereas those from calcined polyhalite yielded mixtures which contained not only potassium and sodium chlorides but also large quantities of glaserite, K3Na (S04)2. Hence it was decided to study the evaporation of the uncalcined poly—halite leach liquor and postpone experiments on the calcined polyhalite liquors until such time as a process for further removal of sulphate was developed.A considerable body of equilibrium data is available in the literature on thesystem K+ Mg++ — Na+ Cl—S04 =,— H20 for temperatures up to 83º C. Owing, however, tothe lack of data other than that corresponding to the invariant points and the complete absence of data for temperatures of 100 to 115°C., and owing to the fact that supersaturation phenomena render unsafe the prediction of the behavior of such a system upon evaporation, it was considered essential to obtain the necessary data by actual evaporation and analysis of the brines thus obtained."

Feb 1, 1931

By A. G. Starliper

Laboratory studies were made to produce whiskers of tungsten over a wide range of operating temperatures. Hydrogen reduction of tungsten hexachloride in a vacuum furnace at temperatures from 2,7000 to 3,3000 C yielded a small quantity of tungsten whiskers, provided a low degree of supersaturation was maintained. Direct measurements of 3,000,000 to 4,000,000 psi were obtained for the ultimate tensile strengths of individual whiskers averaging 3 to 4 microns in diameter with average aspect ratios of 1,000. This compares with strengths of 300,000 to 400,000 psi for 13-micron-diameter commercial filaments.

Jan 1, 1968

By George E. Blandford

A deterministic model to assess the hydrologic impact of small watersheds subjected to unsteady storm events is presented. The overland flow model is based on the kinematic wave approximation coupled with a Green-Ampt infiltration equation. The Green-Ampt infiltration parameters are estimated using the USDA-ARS parameter estimation technique which is based on soil moisture-tension data. A Galerkin finite element formulation of the kinematic wave approximation is presented for the deterministic analysis of overland flow on small watersheds. The finite element formulation includes linear, quadratic and cubic Lagrangian one-dimensional spatial elements. A linear time variation is assumed which includes both explicit and implicit time marching algorithms, depending on the choice of the time weighting parameter. The implicit time algorithms result in a system of nonlinear equations which are evaluated using a modified Newton-Raphson iteration scheme. Initial solution estimates are generated using a linear finite difference procedure. The coupled infiltration overland flow model is tested using storm data for impervious surfaces, a laboratory soil flume, and two natural, USDA-ARS experimental watersheds.

Jan 1, 1983

By Emery Chilton, Charles Taylor, Mark Senk, Linda McWilliams

Three-axis ultrasonic anemometers are used to study airflow in the NIOSH ventilation gallery where ventilation in an underground mine is simulated. In this study, performance characteristics of this anemometer are evaluated and the effects of sensor orientation and sampler location on flow readings are examined. The study results provide guidelines for more effective use of the ultrasonic anemometers in the ventilation gallery.

By M. P. Youker

USE OF LOW-PRESSURE GAS BURNERS IN OIL- FIELD BOILERS

Feb 1, 1922

By Summer S. Smith

The year 1916 broke all previous records of mineral production in the Territory. As a consequence, there has been a noteworthy increase in the number of mines in active operation or under development, though the greater part of the increased output is the result of greater activity at mines already producing rather than of opening new mines. Owing to available funds not being sufficient to meet the cost of travel in the interior of the Territory during the winter months, the Federal mine inspector was unable during the spring to visit the placer mines of the interior as has been his custom in the past. However, by working in close cooperation with the Territorial in- spector, who left Juneau in June to take the first boat down the Yukon to Fairbanks after the spring break-up, it was possible to visit hurriedly all the larger mining centers of the Territory. The Territorial inspector covered the districts from Fairbanks to Nome and the Federal inspector covered those of southeastern and south- western Alaska. A number of applicants have begun mining coal on ground held under free-use 10-acre permits, and have furnished coal for local use. The larger leasing units in the Bering River and Matanuska coal fields have been advertised and applications for leases have been submitted. These applications came too late in the fall for active development to begin before the end of the year. The Government railroad has been built from Anchorage to the center of the Matanuska coal field, and private interests have under- taken the building of a standard-gage road from a point known as Goose City on Controller Bay to Canyon Creek, in the Bering River field. Capital has become interested in the oil fields on Controller Bay, and plans have been made for more active exploration and production. The work of the Federal mine inspector is still handicapped by the lack of funds for additional field assistants and of the office ac- commodations necessary for carrying on the work with the efficiency that its importance warrants.

Jan 1, 1917

By Fred A. Williams

The cause of many deaths and extensive property damage in coal mines resulting from explosions and mine fires has been directly attributable to electric cable failures (including splice failures). The Federal Bureau of Mines data show that out of 355 underground coal mine fires investigated from July 1952 to January 1960, 103 (29 percent) were directly related to trailing cables. These cable failures resulted in the death of 7 men and injuries to 37 others. These potential hazards have become greater, obviously, through the widespread adoption of mechanized mining methods with electric-driven machinery powered through trailing cables according to Young,4 68.1 percent of the total bituminous and lignite production of the United States was mined underground in 1959. About 85 percent of this production was attained by mechanized loading methods. A large majority of the mines using the hand- loading methods also used equipment with trailing cables such as cutting machines, drills, and gathering locomotives. The problem of minimizing the loss of life, resources, and equipment from cable failures should be of concern to the management of all coal mines. It would be misleading to imply that no consideration has been given to the problem and its associated hazards. Through research cable manufacturers have endeavored to develop trailing cables that will withstand the severe service imposed by underground mining conditions. Technical research groups have undertaken studies for determining improved procedure and materials for field splices. Coal companies have instituted cable maintenance programs with a view toward the reduction of cable failures and consequent improvement in safety and efficiency of operations. Safety agencies are alert to unsatisfactory cable handling practices, poor workmanship in field splicing, mechanical

Jan 1, 1962

By J. W. Paul

A study of mining methods and underground practices as they influence injury from falls of roof or coal reveals data as to the location in the mine where such injuries occur with the greatest frequency and as to some of the methods and practices which are in use for the prevention of injury. This paper, which presents statistics bearing on the frequency and place of occurrence of accidents and discusses regulations and practices which have resulted in a low-frequency rates from falls of roof and coal in a few representative mines, takes its information from mine-accident reports and from the results of studies conducted in a group of 80 mines in the bituminous coal fields of Western Pennsylvania, Ohio, and West Virginia. The statistics from this group of mines cover periods of one to four years but average 2 years and 7 months. During this time these mines produced over 110,400,000 tons of coal, equivalent to one-fifth of the annual production of all bituminous mines in the United States. The coal beds of the mines in the group studied are mostly flat, with local pitches of moderate degree. A number of mining plans are in use, each of which follows a general system of multiple entries, gross entries, and rooms. Room and pillar in panels either advancing, retreating, or half advance and half retreat, and the block system are employed. The methods of pillar extraction are by splitting, slabbing, pocket-and-stump, and open end. It is hoped that in presenting some of the details of the methods and practices at particular mines of this group which have commendable records in the prevention of injury some goad may accrue to many other bituminous mines which have similar natural conditions.

Jan 1, 1933