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By Donald L. Siebert

This profile study of the commercial secondary aluminum industry examines not only the elements that form the industry but also the technological contributions of each toward industrial growth. Concise descriptions of processing methods trace aluminum scrap from generating sources to marketable industrial and consumer goods. Economic and marketing appraisals are used to illustrate the impact that recent technology has had upon the secondary aluminum industry. Price, supply, demand, competition, and substitutes are selected as components of an economic model of the secondary industry and are used to illustrate the aggregate effects of technological changes. The final section is a conceptual look at the future in which sensitive economic indicators (such as die casting in the automotive and appliance industries) are examined as well as the problems of conserving mineral resources by retrieving secondary aluminum from solid waste.

Jan 1, 1970

By Norman L. Wimmler

Active placer mining in Alaska began near Juneau in 1880, but the first gold rush did not start until 1896; then the discovery of the Klondike brought gold seekers from all parts of the world. A few of the newcomers were experienced miners, but the majority knew nothing whatever of placer mining. Even those who were placer miners of much experience found entirely new conditions, notably frozen ground, that presented many difficult problems. As a result, numerous methods of mining and of thawing frozen ground were tried. From these trials the practice described in this bulletin has been developed. All known placer fields in Alaska have been mined to some extent, and some have been virtually exhausted. In most districts, however, there remain large quantities of low-grade gravel and also some small isolated areas of comparatively rich gravels which could not be successfully mined because of adverse physical conditions. These districts are now the scene of most placer mining, including dredging, hydraulicking, drifting, mechanical methods of open-cut mining, and ground sluicing (or booming) followed by " shoveling-in."

Jan 1, 1927

By Amitava Ghosh

A new analytical formula for predicting ground vibrations induced by blasting is proposed. One factor accounts for geometrical spreading. One factor corresponds to inelastic attenuation. The geometrical spreading function is based on likely source geometries, idealized as either square-root, cube-root or site-specific scaling, and on the propagation characteristics of predominant wave types. The inelastic attenuation is approximated by an exponential function. The empirical constants in these functions are backcalculated from field measurements. Regression analysis has been performed on twenty-three sets of measured data in order to determine the validity and the effectiveness of the proposed method. In many cases, the proposed method gives better correlation than the conventional method. In most of the remaining cases, there was no difference between the two methods. Best-fit lines given by the proposed method fit the data trend very well, especially at large scaled distances. At large distances the proposed method gives a prediction much closer to the actual values than the conventional methods. The statistical analysis shows not much difference between square-root, cube-root or site-specific scalings.

Jan 1, 1983

By T. L. Johnston

A review of technical literature of the last quarter century discloses that much experimental work has been carried on in an effort to develop commercial processes for making sponge iron. In addition to the work that has been recorded, other work has been done the results of which have not been published. The degree of success or failure of these investigators does not detract from the fact that the problem has its challenging aspects and practical possibilities that encourage further investigation. The purpose of this report is to record information derived from recent experimental work that .had its 'objective the development and demonstration of one method of producing sponge iron. Work of other investigators was studied and applied wherever possible.

Jan 1, 1948

By A. L. Engel

In recent investigations of chloride Volatilization of gold at the Reno Station, it was found that the addition of small amounts of copper and NaCl to the charge brought about improved volatilization of the gold. The investigations described in this report were concerned with the recovery, in an aqueous medium, of fumes from chloride volatilization of gold. It was attempted to discover a suitable aqueous medium that would permit absorption, solution, or precipitation of all the volatilized gold immediately upon contact with the medium. A simple laboratory apparatus was employed to produce fumes by volatilization. To this furnace was attached an absorption train consisting of a series of chambers containing the aqueous medium, through which the fumes were drawn by suction. A satisfactory synthetic ore that contained metallic, gold in a quartz-matrix was made and utilized, enough. gold being present in a' small amount of material to permit an accurate, metallurgical balance of the volatized values' to be obtained in all the experiments.

Jan 1, 1949

By A. C. Fieldner, G. W. Jones

Tests were made at the Government Fuel Yard , operated at Washington , D. C. by the Bureau of Mines , Department of the Interior , in order to determine and improve the adjustment of the carburetors on the trucks used for transporting coal from the Fuel Yard to the different Government buildings in Washington . The tests were made possible through the hearty cooperation of G , S. Pope , engineer in charge of the Fuel Yard . Joseph Burrows and A. E. Foote of the garage department assisted during all the tests and supplied information on the mileage obtained by the trucks for the months preceding and succeding the time the tests were made . The Mack trucks used range in capacity from 2-1/2 to 7-1/2 ttoonnss .. The majority of the carburetors were Stromberg G- 3 type , as shown in Table 2. During the winter months , when the demand for coal is heavy , from 30 to 35 trucks are used . At the time the tests were made , only about ten of the trucks were in daily use , owing to the small demand for coal during the summer months , and scarcity due to labor conditions . Samples of the exhaust gas were taken on the trucks kept in service for summer hauling in order to determine the carburetor adjustment as used . Changes were then made to a more economical adjustment wherever possible , without sacrificing flexibility of operation and power . In every case the adjustments were maintained for maximum power , but were adjusted to the leanest position to give that power . In all but one case the carburetors were found to be adjusted too rich for maximum power and economy . These results are considered in detail in a later part of this report .

Jun 1, 1923

By Koehler Stout

Previous work done by the authors of this report indicates that hydraulically-placed backfill can be strengthened several fold by various placement methods. Sunshine mill tailings were tested by these placement methods and strength increases up to thirty times were achieved over the ordinary placement methods. A computer simulation study of the test stope in the Sunshine Mine showed that a high-modulus fill absorbs up to 27% of normal stresses versus 7% for "normal" fill while reducing maximum convergence 28% versus 8% for "normal" fill. Although high-modulus fill was not placed in the test stope during this contract, various instrumentation was purchased, designed and built to record necessary data in the stope. Stress gauges were placed in the pillars and recorded data corresponded quite closely with theoretical projections.

Jan 1, 1983

By L. C. IlsLey

So many subjects are covered in State mine-safety regulations that any attempt to compare different State laws in their entirety would be futile. On the other hand, if one selects a single phase or branch of safety work, such a comparison may prove profitable. The subject selected for study in this paper is limited to legislation or regulations dealing specifically with safeguarding (electric) motored equipment used in gassy mines. T When one reads glowing accounts of the safety activities being carried on here and there it is easy to believe that everything which is right and proper is being done to safeguard the mine.workers; but, when one takes time to look into the weakness of many State regulations, it is evident that there is still room for improvement. Undoubtedly it would have been much better for the safety of mines if electrical equipment had been introduced into mines 50 years earlier. If electricity had been in general use when the first mine regulations were pre- pared, those formulating the rules would have covered this hazard along with other hazards, but as electricity came in at a later period, safe mine legisla- tion regarding it has been woefully neglected. Today the United States in general is far behind most other coal-producing nations in the provision of adequate safety rules or laws for the installation and maintenance of electrical equipment and wiring. Returning to the subject of our study, approximately 30 of the 48 States mine coal. More than 20 of these States' produce coal in large quantities. How- ever, of the 30 States only four, 3 Pennsylvania, Utah, Washington, and West Virginia, have laws which specially call for the use of explosion-proof types

Jan 1, 1929

By P. H. Floyd

This report presents the results of laboratory and continuous mill-beneficiation tests conducted at the Bureau of Mines Northwest Electra Development laboratory, Albany, Oreg., on nonsulfide lead ore from the Sherman mine, Leland district, near Burke, Idaho. The predominant lead-bearing mineral in the ore sample treated was pyromorphite, a minor ore mineral of lead. Known reserves of pyromorphite lead ore in the United States are limited, although an appreciable tonnage of this type of ore is found in the Sherman mine. Very little pyromorphite is being mined in this mine or in the United States. This beneficiation problem presented a unique opportunity to study the mineral-dressing properties of a less widely known lead mineral, and consequently adds valuable knowledge to the ways of beneficiating ores containing nonsulfide lead values. This mineral-dressing problem was successful with conventional concentration methods of flotation and Gravity separation.

Jan 1, 1952

By W. D. Ryan

Industry must be made to realize that "Safety First" means just that - safety first. The miner must realize that safety first takes precedence over earnings. The employer must realize that safety is the first consideration, and is not to be subordinated to profit-making. Neither employee nor employer is justified in adopting the principle of safety first with reservations; that is they will practice safety first only so long as they think that it does not interfere with earnings or profits. This paper proposes to demonstrate that suberdinating safety to possible profit is short-sighted and that over an ex- tended period of time it dres not result in increased profits or earnings. An employee through disregard of safe practice may receive an injury that will cause him a loss of earnings if, indeed, he is net killed or permanently in- capacitated. If permanently incapacitated any compensation he may receive is very likely to be wholly inadequate as compared with probable earnings if the accident had not cccurred. The employer, upon his part, will find that the burden of compensating his injured employse will far exceed the outlay of money necessary to maintain a reasonable program of safety in his mine or plant. The mine foreman is one of the most important factors in the matter of mine safety. A vigilant and competent mine foreman, once he has established the confidence of the employees in his ability as a foreman, can be of invalu- able assistance in promoting mine safety, for through him and his assistants the employees may be made to cooperate. Every employer should remember, then, that the soluction of the foremen and their assistants is one of the most important matters connected with the work of establishing the maximum amount of safety in his mine. Everyone connected with the mining industry must be made to realize that there is to be no back-sliding and no let-up in safety work; that no matter how dry and tedious the routine may seem it is absolutely essential and justi- fied for both humanitarian and economical reasons. Efficient safety effort pays dividends in actual cash to both employer and employee. About 50 per cent of underground accidents in coal mines take place at the working face where the miners dig and load the coal. Approximately 17 per cent of coal-mine fatal accidents are the result of underground haulage. Face and haulage accidents can and will be reduced materially if the individual miner takes all precautions necessary to protect himself and if the management

Jun 1, 1930

By Richard W. Knostman

A study was made of the factors affecting lead and zinc production in the Pacific Northwest. Costs, ore reserves and potential resources, and domestic demand were analyzed. It was concluded that a projected 3.1-percent average annual increase in U.S. demand for zinc through 1975 and a corresponding 2.5-percent rise for lead will be supplied mainly from mines in the Eastern and Central States. Annual Pacific Northwest mine production of lead is estimated to fluctuate around 82,000 tons, while zinc output may average 135,000 tons through 1975. Measured, indicated, and inferred reserves in the Pacific Northwest, containing 1.56 million tons of lead and 2.59 million tons of zinc, are more than sufficient to maintain this level of production. Annual production from Pacific Northwest electrolytic zinc plants is expected to increase to over 300,000 tons of slab zinc by 1975. Lead smelters may experience difficulty in maintaining output at 1964 levels.

Jan 1, 1967

By Katherine A. Margolis

Refuge Chamber Expectations Training was created by a multidisciplinary team at the National Institute for Occupational Safety and Health (NIOSH) to inform miners of what to expect psychologically and physically if it became necessary to use a refuge chamber in a mine emergency. The presentation can be used either for one large group or for individual miners. The training is a multimedia Adobe Flash presentation containing pictures, audio, video, and interviews with miners who have used a refuge chamber in an emergency. It must be run on a computer with Adobe Flash Player installed (refer to the computer system requirements section).

Oct 1, 2009

By Merwin H. Howes

In constructing the NORAD Combat Operations Center, controlled blasting techniques were employed to achieve smooth walls and to avoid shattering the rock beyond excavation lines. Extraordinary measures were taken to stabilize the rock to permanently preserve the openings. Rock stabilization was accomplished by means of reinforced concrete and gunite linings, rock boltings, installation of chain-link fabric, and epoxy resin and cement grouting. A particular zone of weakness at a vital location was supported by exceptionally thick reinforced concrete lining, rock bolts, and cement grout.

Jan 1, 1966

By Richard W. Lusignea

This report describes a program to evaluate the feasibility of determining roof features which occur in United States coal mines from changes in bolting machine drilling parameters. The ultimate purpose of this effort is the development of an instrumented roof bolting machine which can detect hazardous roof conditions and/or indicate when the existing roof control plan is inadequate. A survey of hazardous conditions occurring in United States coal mines is included, along with the slang expressions for these conditions, and their relative degree of hazard. Specific machine parameters are identified for detecting the specific roof conditions. Measurement concepts are proposed using readily available instrumentation in most cases. Various systems are evaluated and tradeoffs presented. An implementation plan is proposed for developing a prototype system and using it in an operating coal mine.

Jan 1, 1978

By Oliver Bowles

The term" sandstone" is applied to a rock composed of mineral grains smaller than pebbles, cemented together more or less firmly. "Conglomerate" is the name given to a rock composed of pebbles, or pebbles and bowlders, of various sizes cemented together. If the pebbles are large and well rounded the rock is sometimes called " pudding stone." Although the term "sandstone" includes all varieties, certain specific terms are applied to types characterized by particular compositions, colors, or uses. "Quartzite" is a variety in which the individual grains are so firmly cemented together with quartz that the rock will fracture as easily through the grains as through the cement; "ferruginous sandstone" is one rich in iron as cementing material, or as grains, or both; "micaceous sandstone" is one in which mica is prominent; " arkose" is a feldspathic or granitic sandstone composed of angular grains; "calcareous sandstone" is one containing considerable calcium carbonate; and" argillaceous sandstone" is one containing considerable clay. The term "flagstone" is used for a rock that splits readily into sheets suitable for flagging; "freestone" for rock than can be cut or carved readily, and with equal ease in all directions; and" ganistel'," in the United States, for sandstone suitable for the manufacture of refractories. Others are named from their characteristic colors such as " bluestone," " redstone," or " brownstone."

Jan 1, 1917

By H. W. Lang

The Bureau of Mines conducted an investigation to observe the effect of cetane improvers upon nitrogen oxides concentration in diesel exhaust gas. Amyl nitrite and amyl nitrate were used as additives to the fuel used in a four-cycle, single cylinder type test engine. It was concluded that nitrogen oxide concentrations were not enhanced at fuel-air ratios above 0.03 pound of fuel per pound of air.

Jan 1, 1969

By Oliver C. Ralston, and others

"INTRODUCTION Investigations of the Nonmetals Division are now conducted at College Park, Md.; Tuscaloosa. Ala.; Seattle, Wash.; and. Norris, Tenn. The last of these was acquired, this year by arrangement with the Tennessee Valley Authority and is engaged in electrothermel research, using power generated by the T.V.A. and. raw materials from that region. In general, the work of the division is concerned with dressing nonmetallic minerals end utilizing the products there-from. Coal, salts, and waters are investigated, and the suitability of apparatus and equipment is studied.As the Metallurgical. Division of the Bureau of Mines makes routine tests of certain nonmetallic ores under prescribed conditions for the public if they are of general interest, the published reports of that division should be read and thus, with the reports of tile Nonmetals Division, the whole field may be covered."

Oct 1, 1939

By R. J. Leary

This investigation was conducted to determine the effects of various rare-earth metal addition practices upon the macrostructure and the pattern of sulfur distribution in steel ingots. Heats of plain carbon steel were melted in a 1-ton, basic electric-arc furnace. Melts were treated with mixtures of rare-earth silicides, aluminum, and cryolite either in the furnace before tap or in the ladle after tap to determine the effects of this form of rare-earth treatment upon ingot macrostructure. Steels thus treated with rare earths in the furnace were characteristically free of the gross subsurface nonmetallics which typically result from conventional rare-earth treatments. Steel treated in the ladle showed only a few such nonmetallics, and practical techniques were developed for eliminating most of these. Results showed that furnace deoxidation was controlled by the concentration ratio of rare earths: aluminum. During casting, deoxidation was controlled by the concentration of rare earths. Oxygen contents equivalent to vacuum ladle degassing resulted from air-melt furnace treatments with the rare-earth mixtures described. Rare earths in steel inhibited the onset of equiaxed grain formation during ingot freezing, and also virtually prevented interdendritic segregation of sulfides.

Jan 1, 1968

By Alvin Kaufman

Increased exploration in Alaska has resulted in many requests to the Bureau of Mines for facts about the mineral resources and mining conditions in the Territory. This report presents information about the minerals of Southeastern Alaska and the factors that affect development of a mining industry in that area. Southeastern Alaska is a narrow coastal strip of rugged mountains and many islands. The climate is mild, with an average annual temperature of 40° and heavy rainfall. Geologically, the region is favorable for deposition of ore; geographic-ally, it is difficult to prospect and to develop, except along areas immediately adjacent to the coastline.

Jan 1, 1958

By Ronald S. Conti

This U.S. Bureau of Mines report discusses the results of research conducted in the Bureau's experimental mine at Lake Lynn Laboratory on the response of fire sensors to simulated mine fires, which included (1) a slowly developing coal-conveyor belt fire, (2) a rapidly burning liquid fuel-belt fire, and (3) a liquid fuel-belt fire in the presence of diesel exhaust. During these tests, several mine fire sensors were evaluated with respect to sensor placement, spacing, and type. The data indicate that smoke sensors alarm several minutes before CO sensors do; and that, in the presence of diesel exhaust, a prototype diesel-discriminating smoke sensor can successfully function without being sensitive to the diesel contaminants. The vertical placement of sensors in the entry near the fire was also shown to be critical in terms of alarm times. Additional data showed that variations exist in response time and level of response for two brands of electrochemical CO sensor. Results also indicate that early detection of fires will improve the probability of miners' escape, because of reduced smoke concentrations during the incipient stages of the fire.

Jan 1, 2010