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By Kevin Phelps, Jason Baird, Philip Mulligan, Dominique Nolan

The basic metric for linear shaped charge performance is the amount of cutting distance that the charge can effectively yield given a specific standoff and target. Due to its size and restricted production runs the 10,500 grain/foot (2,232.25 grams/meter) linear shaped charge has had only limited studies that examine cutting performance and standoff. This article covers research regarding cutting performance verses standoff as the charge is applied to common structural steel. Specifically this study uses A36 mild carbon structural steel blocks of 10.16 cm by 11.80 cm by 35.56 cm and standoff distances of 0.5, 1.0, 1.5, and 2.0 charge diameters. Data presented includes the presentation of actual cutting performance numbers, comparison of that data to projected performance based on currently recognized industry guidelines, and a discussion of what may contribute to the performance found in this study.

Jan 1, 2013

By B. J. Jody

Each year, about 11 million tons of metals (ferrous and nonferrous) are recovered in the U.S. from about 10 million discarded automobiles. The recovered metals account for about 75% of the total weight of the discarded vehicles. The balance of the material or shredder residue, which amounts to about 3 million tons annually, is currently landfilled. The residue contains a diversity of potentially recyclable materials, including polyurethane foams, iron oxides, and certain thermoplastics. This paper discusses a process under development at Argonne National Laboratory to separate and recover the recyclable materials from this waste stream. The process consists essentially of two- stages. First, a physical separation is used to recover the foams and the metal oxides, followed by a chemical process to extract certain thermoplastics. The status of the technology is discussed, and the process economics are reviewed.

Jan 1, 1994

By Yihan Liu, Jintao Zhang, Chen Xiao, Xiaomeng Zhao, Guanglei Song

To estimate the performance of the inert anode materials based on NiFe2O4 spinel ceramic during it used for aluminum electrolysis, we investigated the wetting process of cryolite molten salt which is in composition of industrial aluminum electrolysis with carbon anode and NiFe2O4 based cermet materials, by means of determination the interface wetting angle between the molten cryolite electrolyte and the solid anodes interface. The results show that the wetting angle between the electrolyte and carbon anode is larger than 90 angulation, this means that they basically can not wetting; however the nickel ferrate spinel ceramics behaves much better. In regard to the NiFe2O4 matrix materials, their initial wetting angles is 76.9. The initial wetting angles for 1.0wt%MnO2, 2.5wt%TiO2 and 0.5wt%V2O5-doped samples are respectively 56.86°, 52.98° and 51.93°. However, after 50s later, all the wetting angles came down below 15°.

Jan 1, 2015

By CHARLES L. WRIGHT

Previous work.-The general plan of work outlined for the Government fuel-testing plant erected at the Louisiana Purchase Exposition, at St. Louis, Mo., in 1904, included investigations relative to the briquetting of coals found in the United States. These investigations embraced the possibility of making satisfactory commercial fuels from lignite or low-grade coals which do not stand shipment well; of benefiting culm or slack coals that are wasted or sold at unremunerative prices; and of improving the furnace efficiency or ability to withstand transportation of good coals. This work was begun in 1904 and was continued in 1905, 1906, and 1907 as an essential part of investigations looking to the determination of methods for reducing waste and increasing efficiency in the utilization of the fuel resources in the United States. The initial briquetting tests at St. Louis, which included examination into the behavior of different coals or mixtures of coals in the briquetting press, experimental study of the merits of various substances used as binders, and consideration of the physical properties and resistance to weather and abrasion of the briquets, have been described.a They demonstrated that satisfactory briquets could be made from most coals, and that by briquetting the commercial value of many low-grade coals and lignites could be raised enough to more than cover the cost of manufacture. Norfolk plant.-The briquetting plant of the Geological Survey was moved from St. Louis, Mo., to Norfolk, Va., in 1907, along with the steam boiler and producer-gas equipment of the fuel-testing plant, as the closing out of the affairs of the Louisiana Purchase Exposition and the consequent removal of the buildings from Forest Park made a change of location necessary. Norfolk was selected largely with a view to the testing of coals for naval purposes, and because of facilities in the way of buildings and materials offered by the Jamestown Exposition Company. The work at Norfolk was chiefly devoted to making steaming and briquet tests of coals which reach the Atlantic seaboard at Norfolk and Newport News and are used by the navy and merchant marine. Two briquet machines were installed at the Norfolk plant, one being the English machine used in briquetting tests by the Geological Survey at St. Louis in 1905 and 1906, and the other an American machine. The briquets made at this plant were tested on locomotives of several railroads entering Norfolk and on the United States torpedo boat Buldle in comparison with the run-of-mine coal used in making them. Some of the tests were conducted by the railroads on their own locomotives, but those on the Biddle and on the locomotive of the Seaboard Air Line Railway were carried on by W. T. Ray and Henry Kreisinger, of the United States Geological Survey. Personnel.-Charles T. Malcolmson continued in general charge of the briquetting section after the removal to Norfolk until January 1, 1908. Walter J. Chapman continued in charge of operation of the briquet machines and of the observations reported under the heading "Details of manufacture." Charles L. Wright supervised the installation of the English briquet machine and later in the year continued the physical tests of briquets and the analyses in the chemical laboratory of the section until January 1, 1908, on which date he was placed in general charge of the work of the section. G. E. Ryder and Ralph Galt also continued with the staff, but the former was obliged to resign soon after the plant was in operation on account of ill health; the latter continued with the section as computer until the close of work on December 1, 1908.

Jan 1, 1911

By J. T. Fyles, C. G. Hewlett

"THE REEVES MACDONALD mine is in the Sa Imo-Pend d'Oreille mining area of southeastern British Columbia. It is on the Nelway-Waneta road 4 miles west of the border-crossing point of Nelway. The Reeves orebody from which all production has come is one of several mineralized zones in easterly-striking limestones occurring between the Pend d'Oreille and the lower part of Salmo River.The property was originally located as two groups of claims by R. M, Reeves and J. H. McDonald. The two groups were consolidated in 1925. and extensive development work was done from then until 1930 and again in 1937, but no ore was shipped. The mine was reopened in 1947 and, between 1949 and 1953, 1,057,804 tons of ore was mined. Concentrates recovered contained 85,626 ounces of silver, 19,394,092 pounds of lead, 72,076,495 pounds of zinc, and 455,051 pounds of cadmium. Low metal prices forced the mine to close in 1953, but operations were resumed in November, 1955.The orebodies at the Reeves MacDonald mine are steeply plunging lead and zinc sulphide replacement deposits in a banded limestone named the Reeves limestone. The orebodies contain pyrite, honey-coloured sphalerite, and galena, and are surrounded by a dolomitized zone. In the Reeves orebody, where the relationships are known, the dolomite has the same general shape as the orebody. Four zones of sulphides are known on the property (see Figure 1). Three of these, the Reeves, B. L., and O'Donnell, are believed to be faulted segments of one mineralized zone. The fourth, the Point ore zone, exposed on the north bank of the Pend d'Oreille River, is not developed and its structural position is not known, but it appears to be a separate deposit."

Jan 1, 1949

By William R. Yernberg

Santa Fe Pacific Gold, headquartered in Albuquerque, NM is expanding its operation at the Twin Creeks Mine in Nevada. The $250-million sulfide expansion project, including the Sage Mill, is under construction and is 80% complete. Also, additional mining equipment has been purchased to haul the sulfide ore to the mill. With the expansion, employment at Twin Creeks is expected to reach approximately 970 people by the end of 1996. Santa Fe Pacific Gold now owns and operates three gold mines in the United States and is involved in several other gold projects. The three currently operating mines are the Twin Creeks, Mesquite and Lone Tree mines. The Mesquite Mine is located in California’s Imperial Valley. Lone Tree is located 55 km (34 miles) southeast of Winnemucca, NV. The company’s total gold production from these operations is expected to be in the range of 26.3 to 26.6 t (845,000 to 855,000 oz) in 1996. This compares to a total production of about 124 kg (4,000 oz) for the company in 1989. Production costs range from $6.90to $7.25/g ($215 to $225/oz). At the end of 1995, the company reported proven and probable reserves of 556.7 t(17.9 million oz) of gold.

Jan 1, 1996

By S. D. Maksirnovic, Fred N. Kissell

The use of vertical surface degasification boreholes with bleeder systems and the use of a timbered bleeder system to degasify gob areas were studied by (the Bureau of Mines. This report describes three gob degasification studies ,conducted in the Pittsburgh coalbed. One study was conducted to determine the number of panels degasified with one large borehole . The study showed that the borehole provided degasification for three panels. Another study was conducted during the retreat of a 35-acre panel with a single-entry and a two-entry bleeder system and a large surface borehole. A major portion of methane emitted from the panel was carried away by the bore- hole, leaving the bleeder entries relatively free of methane. The last study was made to determine the effectiveness of a timbered bleeder system. The bleeder entries successfully degasified the gob area when enough entries were available and adequate pressure was available to force the air through roof falls.

Jan 1, 1980

By Silvia Serranti, Giuseppe Bonifazi, Roberta Palmieri

The possibility to develop an efficient recovery and reuse of concrete materials from Demolition Waste (DW) represents one of the main targets applied to end-of-life constructions dismantling/recycling. The need to recycle end-of life concrete materials is strongly increasing in these last years for several reasons: i) the decrease of steady supplies of good quality natural aggregates, ii) the need to secure ample supplies of concrete aggregates to the construction industry and, finally, iii) the environmental constraints limiting the DW wastes disposal. The fulfilment of these goals produces several benefits, that is: i) a reduction of new resources consumption, ii) a strong reduction of the costs linked to transport and energy production, iii) the possibility to utilize materials, otherwise lost (e.g. land filled), iv) land preservation and, finally, v) the reduction of the environmental impact of new exploitation activities. A lot of efforts have been addressed to develop, set-up and apply innovative technologies to maximize DW conversion into useful secondary raw materials. The possibility to utilize efficient, reliable and low cost analytical tools to perform detection/control actions: i) to assess concrete characteristics, before demolition, and ii) to detect the presence of contaminants in coarse aggregates (e.g. bricks, gypsum, steel, glass, plastics, wood, etc.) represent the key issues to fulfil in order to develop innovative process/control actions/procedures inside the DW sector. In this paper a new technology, based on HyperSpectral Imaging (HSI) sensors is investigated to develop suitable and low cost strategies finalised to define and implement innovative smart detection engines for sorting and/or DW flow stream quality control, addressed to perform recovered materials and/or products certification. The proposed sensing architecture is fast, accurate, affordable and it can strongly contribute to bring down the economic threshold above which recycling is cost efficient.

Jan 1, 2014

By J. M. Johns

INTRODUCTION The Climax Mine is located on the continen¬tal divide, on Fremont Pass, about 145 Km south west of Denver, Colorado. Molybdenum, along with the by products, tungsten, tin, and pyrite are produced from both the open pit and under¬ground operations. The underground operation utilizes a panel caving mining system, and produces in excess of 27,000 mt per day. In the mid 1930's, the Climax mine began changing from a grizzly level layout to the slusher drift system which is still in use to¬ day. Over the years, the slusher drift layout has been refined to correct, improve, and sim¬plify minor operational problems. In common with most older hardrock mines, the development equipment used at Climax was the standard rail mounted, pneumatic mining machinery. This type of equipment remained in use, at least to some degree, until about four years ago. For production, 112 Kw electric slushers were used, while mine traffic was rail with trolley locomotives. Beginning about ten years ago, Climax began

Jan 1, 1981

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 C. J. Beyke

The U.S. Bureau of Mines has developed a process for the selective recovery of Pb metal from a mixed Pb-Zn concentrate. The concentrate was leached in recycled H2SiF6 at atmospheric pressure and 95° C with a redox potential of 570 mV (Eh). Eighty-five pct of the Pb was selectively leached from the concentrate while 87 pct of the Zn remained in the residue. Pressure leaching of the concentrate was slightly less successful, with 78 pct of the Pb leaching from the concentrate and 80 pct of the Zn remaining in the residue. Pure Pb metal was successfully electrowon from a purified PbSiF6-H2SiF6 solution with 96 pct current efficiency and 0.69-kW.h/kg energy consumption.

Jan 1, 1991

By Kang-In Rhee

Nonferrous metal recycling not only provides energy saving and environmental benefits but also is a significant factor in the supply of various types of metals used in our society. Recycling plays an important role in establishing the sustainability of materials. The total amount of recycled nonferrous metals by weight accounts for less than 5% but their value is larger than 50% compared to ferrous metal recycling which consists of about half of the total metal recycling in weight. This paper describes trends and typical achievements in nonferrous metal recycling and overviews the present and future of nonferrous metal recycling technology and business in Korea.

Jan 1, 2006

By Sigmund Black

Ingersoll-Rand Research, T n c and the Lee-Norse Co. built a Bureau of Mines sponsored, special deep cutting continuous miner under this contract to study the effects of rotational speed and depth of cut on airborne respirable dust. After preliminary tests indicated and later verified that deep cutting - low rotational speed reduces airborne respirable dust, a series of underground tests were performed (9 combinations of rotational speed and depth of cut at 45° bit angle and 4" bit spacing). Additional data was obtained on specific energy, coal sizing and noise. The conclusions reached from the tests results were; a) deep cutting reduces airborne respirable dust generated and specific energy needed to cut coal., b) the greater majority of the decrease occurs in going from 1" to 2" depth of cut, c) lowering rotational speed has a particularly sizable effect of reducing the amount of dust at the operator's location, d) no significant relationship was found for either noise level or coal sizing to rotational speed or depth of cut. Recommendations include. a)) use of specific energy as an indicator of the change in dust level correlating to changes in cutting parameters, b) mine operators should acquire new deep cutting machines., since retrofitting would be selective.

Jan 1, 1977

By Kang-In Rhee

A series of processes to recover the gold from electronic scrap which contains initially about 200-600 ppm Au have been developed. First, mechanical beneficiation including shredding, crushing and screening was employed. Results showed that 99 percent of gold component leaves in the fraction of under 1 mm of crushed scrap and its concentration was enriched to about 800 ppm without incineration. The scrap was leached in 50% aqua regia solution and gold was dissolved completely at 60°C within 2 hours. Other valuable metals such as silver, copper, nickel and iron were also dissolved. This resulting solution was boiled to remove nitrous compounds in the leachate. Finally, a newly designed electrolyzer was tested to recover the gold metal. More than 99% of gold and silver were recovered within an hour in electrowinning process.

Jan 1, 1995

By James L. Elder

Field-scale experiments were conducted at Gorgas, Ala., from 1951 to 1954. Three reaction paths were formed by electrolinking-carbonization, using electrode spacings of 150, 152, and 155 feet. The coal along these reaction paths was gasified, using air, oxygen, and steam separately or in various combinations. At the conclusion of operation, a drilling survey was conducted to determine the location and approximate area of the reaction zones. During the applications of the electrolinking-carbonization technique the maximum limitation on electrode spacing was not determined. Initial tests were conducted at 60-foot spacing. Successful path-preparation tests were made at 150-, 152-, and 155-foot spacings, and the indications were that much longer spacings were possible. The potential requirements appear to be constant, regardless of path length, while the gross power required probably will increase with path length. During the carbonization phase gas was produced that is similar in quality to coke-oven gas produced at low to intermediate temperatures.

Jan 1, 1957

A description is given of a detailed examination of a coal bore core and of attempts to predict properties of equivalent "as-mined" coal using the bore core data so obtained. The accuracy of the prediction was measured by testing independently a large sample of coal which was produced under near mining conditions from a site adjacent to the bore core. Very encouraging results were obtained particularly in the prediction of size and ash distributions and washability characteristics of run-of-mine Coal.

Jan 1, 1972

By D. Harrington

The greatly extended use of the underground trolley-locomotive system for hauling coal without doubt was one of the most important factors in the rapid progress of coal mining and the increased production of coal in American coal mines during the period 1910-20. Much of the superior efficiency of production of our underground coal and metal lines should also be credited to the trolley locomotive system. The trend to mechanization of mines during the past 15 years, mere particularly the past 5 years, with higher production per man employed and greatly accelerated advancement of working places, has required increased use of trolley locomotives, necessitating larger equipment, higher speeds, and more 'frequent turn over of pit cars. This is re¬flected in increased size of locomotives and the use of larger mine ears (some with a capacity up to or over 10 tons); moreover, heavier rails and larger-size trolley wires have boon or ought to have boon installed. Trolley-locomotive haulage has proved to be rapid; economical, efficient, and productive; nevertheless; in spite of these advantages, so-many hazardous features and, unsafe conditions are involved and the price paid in life and property is so high as to justify the statement that the system should be scrapped if it cannot be operated under reasonably safe conditions. Since bare trolloy wires were introduced into underground mines, they have boon responsible for the death of hundreds of diners, property damage totaling millions of dollars, an indeterminate loss of tonnage through the abandonment of mines or parts of mines, and loss of time after disasters caused by fires or explosions originated by the trolley haulage system.

Jan 1, 1945

By Donald V. Currie

"The Alberta and Northwest Chamber of Mines was founded in Edmonton, Alberta in 1935. The organization represented private sector mining explorers and developers in the province and north west Canada. The Chamber aided and abetted the establishment of the two territorial mining associations. Because of corporate human resource department creation by north of sixty mine operators, the Chamber refocused on Alberta and broadened its perspective to include activities beyond mining. In 1977 the name changed to the Alberta Chamber of resources. The slogan (in more modern terms vision, mandate, goal, etc) remains as Orderly Development of Canada's Resources.The sixty-three year reputation of the Chamber, built on volunteer rather than staff contribution, is the principal reason for any success. The key has truly been the reputation, not an image, as all activities have been solution oriented.This presentation provides insight into the structure and methodology applied by the organization, and reviews some of the successes and failures during the period 1985 to present. Examples discussed include:• Canada-Alberta Partnership on Minerals 1992-1995• Regional Upgrader Business Plan• National Oil Sands Task Force• Lakeland and Waterways Railway"

Jan 1, 1998

By W. M. Robertson

The rate of crack Propagation thvough a solid meta1 in the presence of a liquid metal has been calculated. The crack is assumed to propagate by solution of the solid in the liquid under the influence of an applied stress, with volume diffusion of the dissolved solute through the liquid controlling the propagation. The calculated velocities can be tens of centimeters per second or higher. THE embrittlement of normally ductile solid metals by liquid metals has been the subject of extensive study, as summarized in the book by Rostoker, McCaughey, and arkuus.' In experimental studies of liquid-metal embrittlement it is usually concluded that the observed crack-propagation rates are too high to be accounted for by diffusion processes. Diffusion is considered to be an unimportant factor and various other mechanisms are invoked to account for the experimental observations. The similarities of liquid-metal embrittlement to stress-corrosion cracking, to hydrogen embrittlement of steel, and to low-temperature embrittlement of bcc metals are frequently used as analogies for these mechanisms.1"3 The present paper assesses how rapidly a crack could propagate by a mechanism of volume diffusion through the liquid metal. We assume that the crack propagates by solution of the solid in the liquid at the crack tip under the influence of the applied stress and diffusion of the dissolved solute away from the crack tip. The model uses only macroscopic thermodynamic, kinetic, and elastic concepts. The calculations indicate that this dissolution-diffusion mechanism can give high crack velocities. In some previous treatments4'' of crack propagation in a liquid-metal environment the fundamental step has been the breaking of atomic bonds at the crack tip. The liquid greatly decreases the energy necessary to break these bonds. The present model assumes the crack is filled with liquid metal; the presence of the liquid is essential because diffusion through the liquid is assumed to control the rate of propagation. With proper modification this model could also apply to stress corrosion in a liquid environment. THEORY Consider a crack in a homogeneous elastic continuum, ignoring all the structural details of the solid. This neglects a host of metallurgical details which can be significant in the problem of liquid-metal embrittlement;' but this simple assumption is a useful approach in evaluating the role of diffusion through the liquid. The stress distribution around the crack tip establishes a gradient in the chemical potential at the tip, which causes a diffusion flux through the liquid away from the tip. The solid-liquid interfacial tension works against crack propagation, since propagation requires creation of interfacial area. From these two considerations we derive the diffusion flux, which then yields an expression for the velocity of the crack tip. The concentration of the solute in the liquid, C, is equal to the equilibrium concentration in the presence of an unstressed, flat surface, Co, plus the excess concentration due to the stress, AC(a), plus the excess concentration due to capillarity, AC(y): We calculate AC(o) and AC(y) and then obtain the diffusion flux. Consider (Fig. 1) a long flat crack of length 2L, thickness 2r, and tip radius r, where r remains constant as the crack propagates in the positive x direction. There is no stress ay in the y direction across the flat surfaces of the crack. The magnitude of the stress at the crack tip due to the applied stress, a,, is given by the relation6 ^=^[l-2^] 12] which, for long narrow cracks, becomes The stress increases the chemical potential in proportion to the strain energy.? The excess chemical potential due to the stress, Ap(a), is given by where 52 is the atomic volume of the solid and E the Young's modulus. Inserting Eq. [3] gives Now consider the crack to be filled with a liquid metal. The excess solubility due to stress, hC(a), is given by the excess chemical potential due to capillarity, Ap(y), is given by8 where y is the solid-liquid interfacial energy, and v1 and YZ are the two principal radii of curvature of any surface point. At the crack tip, r1 = -r and vz = m, so TRANSACTIONS OF THE METALLURGICAL SOCIETY OF AIME

Jan 1, 1967

By Melvin E. Poad

This Bureau of Mines report presents two phases of a research program to evaluate a single-entry system for longwall development. Organizations participating in the program; which began in July 1971, include the Bureau of Mines, the Mining Enforcement and Safety Administration, and the University of Utah, working under a cooperative agreement with Kaiser Steel Corp. at its Sunnyside mine in Utah. Part 1 of this report describes the present longwall mining practice, including a brief history, and discusses the advantages and disadvantages of a single-entry development system and its introduction in the United States. Part 2 of the report presents the research program; test design, instrumentation for ground and support evaluation, and the test results from the No. 2 mine. Subsequent reports will describe the research conducted in the No. 1 mine.

Jan 1, 1977