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By D. E. Munson, H. J. Sutherland

Surface subsidence caused by underground mining is described through complementary influence functions. The complementary functions developed here differ from the simple functions previously used in that the surface displacement is the result of the combined contributions of the mined and unmined zones. This eliminates computational difficulties experienced with the simple functions in determining the deflections above the rib side and in the eventual application of influence functions to complex room-and-pillar configurations. Although the analysis framework presented is intended for predicting subsidence over complex mine configurations, use of the complementary functions is illustrated adequately by application to a longwall panel of the Old Ben No. 24 coal mine.

Jan 1, 1982

By John M. Hird

A section of unstable overburden that has hampered an all-dragline mining operations at Texasgulf's phosphate mine in eastern North Carolina, is being successfully removed by hydraulic dredging. Blocks are dredged, drained, and developed ahead of two large draglines that strip the remaining overburden and mine the 12-m section of ore. Dredging assistance has increased ore production, increased ore recoveries to a maximum, reduced unit costs, and has made it possible to reclaim mined-over land that would be left underwater mined by all dragline methods.

Jan 1, 1981

US 4,195,426-Manganese nodules are recovered from relatively great depths on the ocean floor using a self- propelled remote-controlled vehicle having a V-shaped tubular structure with a system of crawlers at its apexes. Underneath each side of the V-shaped structure is a scraping system for gathering nodules and directing them into a tubular conveying system for elevation to the surface ship. A given area of sea bed is fully mined in a single pass of the vehicle. V. Banzoli, V. Di Tella, and P Vielmo, assigned to Tecnomare, SPA. Apr. 1, 1980. 5 pp. 137-60) Filed. 3-31-78 (892,197). Priority: Italy, 4-1-77 (84119A/77).

Jan 1, 1982

The Institute conducts jointly with the American Society of Civil Engineers, American Society of Mechanical Engineers and American Institute of Electrical Engineers, certain activities as listed below, and is joint owner with them of certain properties. United Engineering Trustees, lnc. When Mr. Carnegie made his gift which made possible a home for the engineering societies, a separate corporation was organized to act as a holding company and to manage the common property. This was long known as the United Engineering Society, but the name has now been changed to one which more nearly reflects the real function of the corporation. It holds title to the Engineering Societies Building and to various funds placed in its charge and is managed by a Board of Trustees, of which three are chosen by each of the four societies, American Institute of Mining and Metallurgical Engineers, American Society of Mechanical Engineers, American Institute of Electrical Engineers and American Society of Civil Engineers, which have equal and undivided interests in. the property. The land and building cost two million dollars. During the year 1934, the Constitution and Bylaws

Jan 1, 1938

By A. T. Stroebel, J. A. Goodwin

Diatomite deposits, the skeletal remains of tiny aquatic plants called diatoms, are found in many parts of the world. Only a few of these deposits are of commercial value. Open pit mining is used in nearly all deposits now being worked. Processing methods range from simple drying, crushing, sizing and packaging to carefully controlled and highly sophisticated calcining and air classification procedures, employing the latest control and testing techniques. The major uses of processed diatomite are infiltration as filter aids and fillers and extenders.

Jan 1, 1983

By J. F. Lazenby, W. F. Abercrombie

The role of the laboratory is described in relation to the prospecting and exploration of kaolin clays. Test method's used to evaluate crude ore samples of kaolin clay for commercial consideration are reviewed. A background of the kaolin mineral and known means of prospecting this mineral are presented. Common analytical methods are discussed with special emphasis on those in use today.

Jan 1, 1983

By Erwin S. Sperry

It is a tradition in the brass industry that bismuth is ail injurious element in brass, even more deleterious than antimony; but such a belief has lacked verification. The occasional presence of bismuth in commercial copper (although less frequent than was formerly supposed) led the author to investigate this tradition. The f'ollowing experiments mere conducted in the same man-

Jan 1, 1899

By J. C. Donnell, O&apos

Sinking an inclined ventilation shaft at the Never Sweat mine of The Anaconda Co. has required a unique underground hoisting arrangement because the shaft changes direction from vertical to 71.5º. Access to the project is made through the High Ore shaft to the 2800-ft level, then by crosscut to the bottom of the vertical Never Sweat shaft. The 71.5º incline shaft starts at this point, which makes an unusual operation as the 60-cu ft sinking skip coming up the incline changes into a vertical position above the 2800-ft level before going into the dump scrolls. This requires both rollers and guide shoes on the skip. Coming up the incline to the collar of the shaft the loaded skip enters into a guard before reaching the vertical section. The tendency of the surface- mounted Never Sweat hoist is to lift the front wheels of the skip off the track, so the guard keeps the skip on the rails during the transition.

Jan 11, 1965

By M. L. Jeremic

Mining practice and underground studies show that, besides mining stresses, lateral tectonic stress also influences roadway stability. Roadways perpendicular to the direction of major lateral stress experience the majority of roof falls, accelerated floor heave, and extrusion of coal ribs into openings. They have the most severe deformations and their maintenance is difficult. Roadways parallel to the major lateral stress exhibit roof sagging and bed separation, moderate though sometimes uneven floor heave, and slabbing of coal ribs into openings. Roadways oblique to lateral stress have, to a certain degree, self-supporting roofs, uniform floor heave, and limited sloughing of coal ribs into openings. The optimal orientation of roadways is, therefore, oblique to the lateral stress direction with fewer crosscuts between them.

Jan 1, 1982

By Calvin C. Brown, John Bigando

Pit slopes at Cananea commonly vary from 50-55°, and some have been standing for over 25 years. Their maximum vertical extent is 700 ft. Investigation of these slopes and the rocks of which they are composed has led to the decision to experiment with final pit slope angles of up to 70". Precision blasting to obtain a smooth final pit wall with minimum raveling is an integral part of this field experiment. Presplitting, one of the precision blasting techniques, requires the drilling of a single row of holes along the limit of a pre- designed excavation. The hole spacings and charge concentrations must be experimentally determined in the field, using published data as a base (Table 1). The holes are fired prior to the main round and carry no burden and therefore produce no broken rock. Thus, it is an operational cost with no direct return on investment.

Jan 9, 1972

By W. C. Lacy

THE Cuajone porphyry copper deposit is the northernmost of a group of three deposits in southern Peru controlled by the Southern Peru Copper Corp.-Toquepala, Quelleveco, and Cuajone- all within a 20-mile belt. Although small pockets of high-grade copper oxide ores were worked in the Cuajone area in the 19th century, it was not until 1939 that its potentialities as a disseminated deposit were recognized by O. C. Schmedeman. An exploratory drilling program was begun in December 1942 and continued until early 1945. The program was revived in November 1952 and completed early in 1954. Early exploration was by diamond drilling. Later exploration was predominantly churn drilling, with diamond drilling used only for wildcat holes.

Jan 1, 1958

By F. J. Budin

Steel supports are increasingly used in metal mines for junctions, chambers, and other wide openings and for semi-permanent areas such as haulageways, shaft stations, and pump rooms. Steel lasts longer-especially in wet mines and where foul air is present-and is procurable in different sizes that will carry heavier loads than any timber of equivalent cross section. The chief advantage of steel supports is that less excavation is needed than with timber support of the same strength, so that faster progress can be made. Since there is no possible way to calculate the exact weight on supports, sizes must be chosen by experience. Any adjustment and cutting of steel supports underground would be costly and time-consuming, and it is therefore advisable to cut sets beforehand at the surface workshops. This requires standardization of sets. All these problems have been recognized at Bawdwin Mines, Burma, where mining is difficult, slow, and very expensive. The lead-silver ore is very brittle, with hanging and footwall rock of unconsolidated rhyolite tuff. During the rainy season from May to October water penetrates into the mine, and where soft rock is present disintegration into a loose mass around openings can be expected. For this reason heavy 10x10-in. timber caps break quickly in drifts and crosscuts, and timber rots in a very short time. An average increase of 50 pct in both maintenance work and costs could not be avoided.

Jan 3, 1960

Advantages to Members of Our Advertising Section.-It is our intention to make the advertising section of the Bulletin as comprehensive as possible, so that members can turn to it for complete information as to where to buy the best mining and metallurgical supplies at the lowest prices. No firms or supplies of dubious reputation are advertised in the Bulletin. If members, in buying any material, will refer to the advertisement of that material in the Bulletin, or if they do not find it advertised in the Bulletin, will, when ordering, ask the manufacturers why the goods were not advertised in the Institute publication, it will be of material benefit to all of us, because the chief reason why advertisers are unable to trace direct results is because purchasers do not mention the Bulletin when writing. Finally, if members, when in need of anything whatsoever, will write to the Institute headquarters, an effort will be made to send them a complete list of manufacturers able to supply the desired materials of good quality. The furnishing of these lists will be a benefit to our Advertising Department, as well as to the members. We need scarcely call attention to the advantages obtained by the members from the money which advertising brings in, because all this money is returned directly to the members in one form or another.

Jan 7, 1913

By Arthur Redfield

THE year 1923 was marked by slight progress in exploring and developing the petroleum resources assumed to exist in Central America. Actual drilling for oil took place only in Costa Rica and Panama. The Sinclair Consolidated Oil Corpn., through its subsidiary the Costa Rica Oil Corpn., drilled in southeastern Costa Rica.. Its, Panaman subsidiary is reported to have abandoned drilling in Bocas del Toro. The Texas Co. drilled in Chiriqui, and the Panama Gulf Co. in Garachiné, Province of Darién. No oil was obtained in any of these wells;' shows of gas were met in Costa Rica. Concession hunting continued during the year. A number of concessions, several of which appear to be purely speculative, were submitted for ratification. Some confusion has been caused by overlapping concessions and claims to oil lands, caused partly by the imperfection of existing maps. A conflict between the Sinclair, and Gulf companies in Panama has been compromised. The Amory concession in central Costa Rica, held by the British Controlled Oilfields, Ltd., was voided by decision of the arbitrator, Chief -Justice Taft. Geologic exploration took-place in Guatemala and in Panama. The chief contribution of the year to Central American geology was a description by Katherine Van Winkle Palmer of Lower Miocene foraminifera and mollusks from southeastern Costa Rica. A new petroleum law was promulgated in Panama.

Jan 3, 1924

The Institute conducts jointly with the American Society of Civil Engineers, American Society of Mechanical Engineers and American Institute of Electrical Engineers, certain activities as listed below, and is joint owner with them of certain properties. United Engineering Trustees, Inc. When Mr. Carnegie made his gift which made possible a home for the engineering societies, a separate corporation was organized to act as a holding company and to manage the common property. This was long known as the United Engineering Society, but the name has now been changed. to one which more nearly reflects the real function of the corporation. It holds title to the Engineering Societies Building and to various funds placed in its charge and is managed by a Board of Trustees, of which three are chosen by each of the four societies, American Institute of Mining and Metallurgical Engineers, American Society of Mechanical Engineers, American Institute of Electrical Engineers and American Society of Civil Engineers, which have equal and undivided interests in the property. The land and building cost two million dollars. During the gear 1934, the constitution and By-laws of The United Engineering Trustees, Inc., were thoroughly revised and a better organization of its functions was affected: The Engineering Foundation and the Engineering Societies Library were made "departments? of the United

Jan 1, 1936

The Institute conducts jointly with the American Society of Civil Engineers, American Society of Mechanical Engineers and American Institute of Electrical Engineers, certain activities as listed below, and is joint owner with them of certain properties situated at 29 West 39th Street in New York City United Engineering Trustees, Inc. When Mr Carnegie made his gift, "for the erection of a suitable union home" for the engineering societies, United Engineering Trustees, Inc (then United Engineering Society) was chartered un¬der Chapter 703, Laws of the State of New York, 1904, for "the advancement of the engineering arts and sciences in all their branches, and to maintain a free public engineering library " The Corporation was further empowered to acquire real and personal property and to use, maintain and occupy it, with the provision that any building erected by the Corporation shall be used perpet¬ually as a meeting place and headquar¬ters for the Founder Societies Thus the Carnegie gift realized the ideal of bring¬ing the engineering societies together under one roof, and the Corporation through its members nominated in equal numbers by the four Founder Societies had the necessary authority to act for the Founder Societies in their joint in¬terests in owning and operating for them not only Engineering Societies Building, but in the course of time, Engineering Societies Library, and The Engineering

Jan 1, 1952

By W. R. Ingalls

DURING 1921, the Oklahoma mines dominated the American zinc-producing industry. They comprised the only group that could produce under the adverse conditions that prevailed. At the beginning of 1921, there were about 34 mills in opera-tion in the Tri-state District, out of a total estimated variously at 150 to 200, and these were producing at the rate of about 5000 tons of blende concentrate per week. At the end of 1921, there were about 50 mills in operation. The Tri-state District rates about 80 men to the mine and mill, on-the average. SMELTING The zinc smelters-in 1921 experienced a disastrous year. All of them operated at greatly reduced capacity and probably most of them suffered loss in operations. Smelting costs came down to a considerable extent by virtue of drops in the price for coal, wage reductions and more efficient work, but these ameliorations were insufficient to enable the smelters to come out even. In the Illinois fields, wages at the end of 1921 had been reduced about 37 per cent. from the peak (middle of 1920), but coal continued to be very dear. The operation of works at a low rate of their capacity was a discouraging and expensive condition. At the end of 1921, the zinc-smelting capacity ,of the United States was as follows:

Jan 7, 1922

By H. B. Charmbury, D. R. Mitchell

Everyone in the coal industry from top management to the preparation engineer is vitally interterested in recovering as much salable coal as possible from the run-of-mine product. Coal losses from a preparation plant occur in the solid refuse material being discharged from the plant and in the bleed-off slurry from the water circuit. The refuse is generally hauled from the plant in solid form by trucks, conveyors, or aerial trams to the refuse or culm banks or it may be crushed and transported by hydraulic methods to refuse ponds or dams. The loss of coal in refuse material and the extent of this problem has been covered in another paper. The loss of salable coal in the plant bleed-off slurry is one of the water circuit problems in coal preparation plants. Slurries originate at various places in the processing circuits and are usually disposed of by transportation to waste ponds known as slurry ponds. Even though the combustible material discharged as slurry and refuse from the plant is labeled a loss, the loss must only be considered temporary. There is a tendency at the present time to examine refuse and slurry losses and to reprocess these materials to recover valuable coal.

Jan 1, 1960

By W. P. Yant

THIS paper presents evidence of the general occurrence of methane in a large number of the coal fields of the United States and substantiates the apparent unnecessary differences in the ventilation requirements and codes in the various states, as was brought to the attention of the Committee on Mine Ventilation of the American Institute of Mining and Metallurgical Engineers at its Pittsburgh meeting in October, 1925, by J. A. Garcia.1 The data in his report have been compiled from the files of the Gas Laboratory of the Pittsburgh Experiment Station of the Bureau of Mines and represent samples collected throughout the various states and submitted for analysis by its engineers, also by mine operators and State mining departments, since 1911. Several thousand analyses were available but most of them were rejected because they represented abnormal conditions, undefined place of sampling, special investigations, or duplications in the same mine. Only those samples were included which, without reasonable doubt, were ascertained to fall within three major classes, namely, main return, air splits, and face and rooms of live workings. In the case of air splits, and face and room samples, only the one which contained the highest percentage of methane found in a given mine was taken.

Jan 1, 1927

By Benjamin B. Lawrence

Arthur Launcelot Collins was born at Truro in Cornmall, England, July 8, 1868. His father, J. H. Collins, is well kuown as an engineer, and his books have been widely read in this country: Arthur was the third son. Three of his brothers are engaged, as is his father, in the profession of mining engineering. His education, gained partly at St. Austell, partly at Falmouth, and partly at Nuttall's Collegiate School in Truro, England, was supervised by his father, who was then Lecturer on the Mining Sciences to the Miners' Association of Cornwall and Devon. In 1881, J. H. Collins went to Rio Tinto, in Spain, as chief chemist and metallurgist, and it was there that Arthur began his practical work in the laboratory and continued his studies in chenlistry and mineralogy. To the latter science he was deeply attached; and he never lost an opportunity of adding to his cabinet of minerals, of which he was an ardent collector. In 1883, he became assayer and general assistant to Mr. Nicol, Manager of the Peña del Hierro copper-mines, ncar Rio Tinto. Until 1885 he was associated with his father in the study of the geology of the Rio Tinto belt. In 1885 he retuined

Jan 1, 1904