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By R. E. Tremoureux

This paper describing the methods and costs of quarrying limestone at Sloan, Nev., is one of a series of similar papers being prepared for and published by the Bureau of Mines on this industry in the United States. These papers are designed to disseminate information regarding the methods used. The cost tabulations represent local operating expenditures only and not total production costs. It is recognized that publication of total production costs might in many instances cause embarrassment to individual producers as well as to the industry as a whole. On the other hand, operating costs are essential to the technical discussion and study of the methods Employed. The attention of the reader is specifically called to this differentiation in order that no misunderstanding of the scope of the cost tabulations shall ensue. The quarrying operations at Sloan are interesting not only from a technical viewpoint and because of the magnitude of the deposit, but also because the quarry is located in a desert region far removed from the centers of population where lime is used. The quarry and plant are in Clark County, Nev., 20 miles west of Las Vegas, which is the nearest town to the site of the Boulder Canyon Dam. Sloan is on the main line of the Union Pacific Railroad connecting Salt Lke City and Los Angeles. The latter city is 280 miles from Sloan and it is the shipping, point for all supplies.

Jan 1, 1932

By P. N. Anyalebechi

The effects of a cross-hatched grooved mold surface topography, casting speed, and superheat on the morphology of solidifying shells of aluminum alloy 3003 have been characterized by a series of immersion tests. The cross-hatched grooves were 0.232 mm deep with wavelength or spacing between 1 mm and 15 mm. The shells solidified at casting speed of less than 10 mm/s on the 1 mm spaced cross-hatched grooved mold surface were fairly uniform with little or no localized variations in thickness. However, the propensity for non-uniform shell growth morphology was exacerbated by an increase in casting speed, melt superheat, and the wavelength of the cross-hatched grooves. This is provisionally attributed to their effects on interfacial heat transfer and wetting of the mold surface by the molten metal.

Jan 1, 2008

By Lloyd A. Morley

Previous research conducted for the USBM by Penn State personnel (Grant GO-101729) found that a need existed to physically model a typical a-c/d-c coal mine section electrical system. Its purpose would be to permit preliminary evaluations of electrical problem solutions prior to launching full-scale investigations. Such use can result in greater flexibility than afforded by present computer models. Furthermore, numerous problems, which would be virtually impossible to incorporate in a computer model at this time, are more easily analyzed with physical simulation. The development of this system is now proceeding at the USBM's Bruceton Research Facilities. However, electrical specifications of scaled down components for its construction are required. This project is a result of that need and has been funded as an extension to Grant GO-133077. The following report covers these specifications. Scope of Work To represent a mined a-c/d-r. coal mine section, the typical component specifications must detail at least: a. one a-c continuous miner, b. two a-c or d-c shuttle cars, c. one a-c or d-c roof bolter, d. one a-c section fan, and e. feeder cables. Further, each machine should be portrayed by each of its general

Jan 1, 1974

By Wallace W. Roepke

Research to evaluate the lubricity effects achieved by spraying water on the cutting bit of a mining machine or spraying water on the coal during cutting has shown that neither practice affects cutting forces, as had been believed. However, when water was supplied to the cutting zone axially through the bit at 3,000 to 5,000 psi pressure, tangent'ial cutting forces were reduced an average of 30 pct at a I-in depth of cut while normal bit forces were reduced an average of 65 pct. Lower normal forces mean reduced bit wear, faster advance with greater depth of cut, and fewer coal fines.

Jan 1, 1985

NEW MEMBERS The following list comprises the names of those persons who became members during. the period Mar. 10, 1919, to Apr. 10, 1919. AFFLECK, B. F., Pres., Universal Portland Cement Co., 210 So. La Salle St., Chicago, Ill. BENSUSAN, ARTHUR J., The Ouro Preto Gold Mines of Brazil, Ltd., Passagem de Marianna, Minas Geraes, Brazil, S. A. BIERBAUM, CHRISTOPHER H., Cons. Engr., & Vice-pres., Lumen Bearing Co., Buffalo, N. Y . DEWITT, OSCAR E., Geol., Vinegar Hill Zinc Co., 622 North Court St., Platteville, Wis. DOTY, L. C Mine Supt., Bullion Beck & Champion Co., Box C, Eureka, Utah. ESPIE, FRANK F Burma Mines, Ltd., Namtu, Upper Burma, Asia. FOZARD, J. L., Gen'l Supt., Beatson Mines, Kennecott Copper Corpn., Latouche, Alaska. GRANT, BENERE Supt., Bulluhacker Min. Co., Butte Mont. HARDEL, JEAN A., Engr., French Government, 21 Rue du Colonel Moll, Paris, France. JANSSEN, WALTER A., Operating Mgr., Canadian Steel Foundries.Ltd., 120 St. James St., Transportation Bldg., Montreal, Canada. KNOWLES, RALPH Roy, Supt., Radium Plant, The Minerals Recovery Co., 457 So. Elati St. Denver Colo.

Jan 5, 1919

By Adam Jordens, Olga Kuzmina, Christopher Marion, Kristian Waters

"In order to meet the growing demand for non-Chinese rare earth suppliers many new rare earth (RE) mineral deposits are currently under development, however these deposits typically include many minerals for which there is little processing information available. One of these deposits is the Nechalacho deposit located in the North West Territories of Canada. This deposit contains multiple RE minerals including bastnäsite, zircon, fergusonite, allanite and monazite. The work presented here investigates the use of different classes of flotation collectors (carboxylic acids, hydroxamic acids, phosphoric acids) typically used in RE mineral flotation to float the Nechalacho ore directly. Flotation tests are also conducted as the final step in a beneficiation process incorporating centrifugal gravity concentration and magnetic separation. This combination of centrifugal gravity concentration and magnetic separation rejects low specific gravity gangue minerals such as K-feldspar and plagioclase and concentrates high specific gravity minerals such as magnetite and hematite. The removal of low specific gravity gangue helps to improve flotation and the removal of ferromagnetic iron oxides is important prior to flotation using certain chelating collectors."

Jan 1, 2014

By Paul M. Tyler

Masurium and rhenium are two elements known only to a few scientists and known to them for scarcely more than five years . The existence of two members of the manganese family was long suspected , and places were left for them in the orderly table of the periodic systemas developed by Mendeljeeff . The empty spaces left in this table some 60 years ago were for elements numbered 43 and 75 , respectively , and since it was evident these were related to manganese they were sought for in research laboratories under the names of ekamanganese and dvimanganese . This nomenclature is in harmony with that usually employed in describing hypothetical elements , and the prefixes are taken descriptively from ancient Sanskrit wherein the word " eka " means one and " dvi " ( also spelled dui or dwi ) means two . Ekamanganese or element 43 was once removed and dvimanganese or element 75 was twice removed from manganese . It was further possible to predict that these elusive elements would not only be related to manganese but would have a great deal in common with certain other elements . It was reasonable to suppose that element 43 , merely because it stood in numerical sequence between element 42 and element 44 , would likewise prove to be intermediate in many other respects . Since its next neighbors were molybdenum ( No. 42 ) on the one hand and ruthenium (No. 44) on the other , ekamanganese could be given in advance what would correspond among persons to a social and economic rating . Similarly , the properties of dvimanganese were likely to be in simple harmony with those of tungsten and with those of osmium , which latter , like ruthenium , is a member of the platinum group of metals . Another inference , although one which could not be stated with scientific certainty , is that these new elements because they have odd instead of even atomic numbers , would be even more sparingly distributed than their near neighbors , none of which is abundant in nature . This inference has been amply supported by available evidence . These elements eluded discovery until 1925 and never have been found except as minute traces in complex association with relatively rare minerals . In 1930 , for the first time , rhenium became available in quantities which give promise of commercial possibilities , but masurium still stands on the border of the unknown , like some distant star speck photographed and identified by vigilant astronomers but invisible without the aid of the powerful tools of science . The telltale flame of element 43 has been charted by its spectrum lines ; but beyond that , little more can be said except perhaps to repeat the forecasts made for ekamanganese before the Noddacks captured it and gave it a definite name . Certain rare - mineral dealers will furnish molybdenite samples from Norway which are said to contain masurium as well as rhenium , but except for a few highly technical statements as to its behavior in the spectrograph , nothing in the way of concrete information on masurium has come to the notice of the present writer . The literature of rhenium is a little less meager and a brief résumé of the data available in the files of the Bureau of Mines may be of interest not merely because of the novelty of the metal but because its unique properties and increasing availability afford a prospect of its finding employment in industry .

Jul 1, 1931

By E. J. Lintner

This paper is one of a series being prepared by the United States Bureau of Mines describing clay mining, crushing, and grinding methods and costs at various operations throughout the United States. These papers are designed to disseminate technical information regarding methods used. The cost tabulations represent local operating expenditures only and not total production costs. It is recognized that in many instances publication of total production costs may cause embarrassment to the individual operator as well as to the industry as a whole. On the other hand, operating costs are essential to a technical discussion and study of the methods employed. The attention of the reader is called specifically to this differentiation in order that no misunderstanding of the scope of the cost tabulations shall ensue. The following report deals with the methods employed by the Malvern Clay Co., Malvern, Carroll County, Ohio. The author wishes to acknowledge the assistance of the following persons: H. C. Ross, vice-president and general manager, and H. C. Dormer, secretary and treasurer.

Jan 1, 1937

By Webster, Wm. Reuben

THE greatly enlarged demand for small sizes of seamless copper tube which has recently occurred, due particularly to the rapid growth of the electric household-refrigerator industry, has emphasized the superiority of phosphorized to tough pitch copper for the purpose of producing this commodity. In the manufacture of this material exceedingly heavy reductions by cold drawing are employed, customary practice involving as much as 90 per cent. reduction of cross-sectional area in four runs without intermediate annealing. Although this superiority has long been recognized by tube makers, no quantitative expression of it has heretofore been published. It is believed that the data herewith presented mill serve this purpose. Recent investigators are not in agreement as to the relative mechanical properties of copper containing small amounts of oxygen as compared with copper containing sufficient oxygen to produce that condition known as tough pitch. Hanson, Marryat and Ford1 found that "oxygen has a relatively small effect on the properties of copper." Johnson, on the contrary, states "it cannot be denied that it (tough pitch copper) is inferior to deoxidized copper . . . where severe mechanical manipulation is concerned." These authorities in the reports of their investigations, as might be expected from their conclusions, do not present data of a character requisite to a conclusive determination of the question.

Jan 1, 1927

Application of flotation for the removal of hydrophobic compounds from soils was studied. Bench scale flotation tests were conducted on artificially contaminated soil, using both conventional mechanically agitated machine and flotation column. Flotation parameters tested include surfactant collector type, conditioning time, flotation time, surfactant dosage, pulp pH, solid/liquid ratio in conditioning and pulp temperature. It is found that with conventional flotation 74% removal of the contaminant was achieved from soil particles in the range of 75-830 µm; with column flotation up to 80% of oil could be removed from the 250-830 µm soil fraction, and 65% from the 75-830 µm fraction. Flotation was found to have considerable potential for cleaning up contaminated soils.

Jan 1, 1998

By N Eriksson

BolidenÆs Aitik mine, located 100 km north of the Arctic Circle in northern Sweden, is one of EuropeÆs largest copper mines. This operation produces 18 Mt of ore per year and 99 per cent of this tonnage needs to be deposited as tailings. The tailings pond currently covers 1140 ha but at closure it will hold around 760 Mt of tailings and occupy an area of 1400 ha. The tailings contain less than one per cent sulfur and only 0.03 per cent copper. The carbonate content is as low as 0.25 per cent but silicates, with substantial accumulated buffering and metal adsorption capacity, are abundant. A programme of comprehensive material characterisation and investigations has been undertaken in order to design a decommissioning strategy that meets the regulatory requirements and secures long-term physical and chemical stability of the deposited tailings. The main concern has been the potential generation of acid rock drainage (ARD). Standard tests using acid base accounting (ABA) and humidity cell tests during 15 weeks were not conclusive regarding the ARD generation potential. The accuracy of the results was considered to be unsatisfactory, therefore the humidity cell tests were gradually extended in time. In total, almost four years of humidity cell tests were conducted on various sets of samples which were selected in order to cover the variation in sulfide content existing on site and in various points of the milling process. The laboratory results were subject to detailed geochemical evaluation in order to fully understand the interaction between acid-producing reactions, driven by weathering of sulfides, and acid-consuming reactions by dissolution of carbonates and alumino-silicates. The laboratory tests were followed by both pilot tests and field measurements in order to estimate the scale dependency between the laboratory and the field results. It was found that sulfide weathering rates in the field were considerably lower than those measured in the laboratory. However, it could not be verified that the tailings top layer would maintain a neutral pH in the long term even under field conditions. Thus, a reviewed tailings management plan, including de-pyritisation of the tailings during the last years of operation, is considered.

Jan 1, 2003

By X. Q. Jiang, D. L. Chen, A. Macwan

Magnesium alloy, being the lightest structural material, is a key candidate for the weight reduction of vehicles in automotive and aerospace industries; however, its poor corrosion resistance and difficulty in deformation are limiting factors. Recently, Al/Mg/Al tri-layered clad sheets have been considered as a promising alternative to improve corrosion resistance and formability of magnesium alloys. The aim of this study was to evaluate the tensile properties and deformation behavior of Al/Mg/Al tri-layer clad sheets at different temperatures and strain rates. Yield strength (YS), ultimate tensile strength (UTS), and elongation were observed to increase with increasing strain rate. With increasing temperature from -40°C to 180°C, YS and UTS decreased and ductility increased. The strain hardening exponent evaluated via three equations of Hollomon, Swift, and Afrin et al. showed a similar increase with increasing strain rate and decreasing temperature. The fractographic analysis showed partial debonding of clad interface especially at higher strain rates and lower temperatures.

Jan 1, 2015

By P. L. Woolf

Seven evaluation tests with blast furnace iron bearing burden materials are described. The effects of pellet strength, fines in the burden, decreasing slag volume, pellet size, eliminating stone with superfluxed sinter, and eliminating stone by prefluxing the pellets were determined. Fluxed pellets and fluxed sinter made with the same ore fines were compared. The tests were conducted under cooperative agreements between the Bureau of Mines and North American steel companies. The objectives were to improve blast furnace practice, expand and develop understanding of the operation and theory, quantify the effects of changes, and explore the limitations of operability. This work was part of an extensive program of blast furnace research in experimental blast furnaces at Bruceton, PA conducted in the years 1958 to 1967.

Jan 1, 1984

Cutter roof failure, a ground control problem that frequently results in massive roof failure, is common in coal mines of the Northern Appala-chian Coal Basin, causing delays in production and posing a safety hazard to mine personnel. The Bureau of Mines is conducting research on the causes of cutter roof failure to gain a basis from which to predict and prevent its occurrence, and to support such roof when failure occurs or is imminent. Research conducted at the Greenwich Collieries North and South Mines, in central Pennsylvania revealed a correlation between the presence of clastic dikes and formation of cutter roof failure. The research con-sisted of in-mine mapping of geologic and deformational features, rock pressure monitoring, core recovery and evaluation, and in situ stress measurement. It was found that roof failure increased in areas where the occurrence of clastic dikes was most frequent, especially where two or more clastic dikes intersect. Staggering of crosscuts prevented the extension of cutters and deterred the occurrence of large falls extending over several break-throughs. In addition, trusses and cribbing were effective in stabilizing clastic dikes and inhibiting the development of cutter roof failure when employed immediately or shortly after mining.

Jan 1, 1987

By Stephen Krickovic, J. E. Carpetta, T. D. Moore

Air quantity-pressure and methane concentration surveys were conducted by the Bureau of Mines in accessible portions of an area being pillared in a Pittsburgh coalbed mine in West Virginia. These included two mined-out and three active butt headings and a bleeder system. The particular mine workings were started in virgin coal directly from a set of main headings; the main reason for the study was the difficulty usually encountered in adequately bleeding the gobs under such conditions. Although the two separate return airways in each active butt heading and the North and 1 Left bleeders contained acceptable methane concentrations (0.01 to 0.78 percent in the butts and 0.73 to 1.0 percent in the bleeders) with significant total methane removal (109 cfm in butts and 631 cfm in bleeders), there were relatively large areas in the gobs with possible minimal airflows. This condition appears to have developed from lack of systematic regulation of the airflow across the gobs and appears to indicate the existence of considerably more methane in the probably low flow areas in the gob.

Jan 1, 1973

By Lix Tafur, Julio Gómez, Vidal Aramburú

Las operaciones de la pequeña minería artesanal de oro se caracterizan por tener bajas recuperaciones, bajo condiciones inseguras de trabajo y consecuencias negativas en el ecosistema por el uso indiscriminado del mercurio y/o cianuro, Con la finalidad de mejorar dicha práctica se desarrollaron pruebas de lixiviación con reactivos alternativos al cianuro para recuperar oro y plata a partir de los relaves de amalgama. El análisis mineralógico determinó la presencia de especies como: oro, pirita, magnetita, hematita, Ilmenita, rutilo y gangas, así mismo los ensayos químicos determinaron una ley de 20.16 g-Au/TM, 147.12 g-Ag/TM y 10.53 ppm de Hg

Sep 29, 2023

By Musa Karakus

The sedimentary iron ores of Alsace-Lorraine, France have very high phosphorous contents that average 0.7% and are as much as 2.19% P. Ores from the Tucquegnieux and Joeuf mines have been studied by cathodoluminescence microscopy, X-ray diffraction, scanning electron microscopy, and electron microprobe analysis in order to fully characterize the mineralogy, size, shape, and distribution of the deleterious phosphate grains. The phosphorous occurs as collophane, a carbonate fluorapatite, in ten morphological forms, most abundantly as microcoprolites, but also as intraclasts, concentric layers, and cortices in ooids, phosphate replaced ooids and bioclasts, phosphatiC shells, fossil infillings and internal molds, fish teeth, phosphatiC laminae, and cements between the goethite ooids. About 95% of the phosphate grains are sufficiently large that relatively fine grinding fol'lowed by reverse flotation would be expected to be effective in significantly diminishing the phosphorous content of the concentrates.

Jan 1, 1989

By K. Hawboldt, J. E. Halfyard, C. Bottaro

The removal of sulfur from leach residues has been practised in the zinc industry using a combination of flotation and hot melt filtration. The process is highly dependent on the nature of the concentrate and the subsequent residue. When the mineral constituency of the residue alters, the process can encounter significant operational challenges. An alternate method of converting elemental sulfur to water-soluble polysulfides was applied to leach residue from Vale's nickel demonstration plant in Argentia, Newfoundland. Reaction parameters, sulfur purity and other key indicators are discussed as is the potential commercial application.

Jan 1, 2011

By Chuck R. McLendon

A new face ventilation system was needed at the Allied Chemical Trona mine, near Green River, Wyoming. The development of an exhaust manifold face ventilation system came from a need to reduce the dust and noise concentration level while maintaining methane control at the continuous miner working face. Dust laden air from a heading being driven by a continuous miner was contaminating the intake air in the mine around the roof bolter operator and adjacent headings. Each working heading was exhausted into the last open crosscut by a face fan. A face fan would contaminate the adjacent downstream heading with dust-laden air until a high dust concentration developed in the final entry before the returns. A face ventilation system was needed to give the exhaust of each heading an individual path to the return air. In addition, the system could not interfere with the present room and pillar mining process. A manifold system of rigid duct ventilation tubing was designed using the existing fans in a parallel arrangement. Each system was to consist of the rigid duct tubing in three headings junctioned together at the last open crosscut and exhausted at a common branch in the return air. Each heading was to have its own damper (or valve) so that air could be directed where it was most needed. The system was installed using both round and oval rigid duct ventilation tubing to minimize head loss and to allow proper ground clearance for mining machinery. Two fans in parallel were used to exhaust three headings. By adjusting the valves at each heading, up to 18.0 kcfm (9.36 cu m per sec) could be exhausted from one heading and still keep the methane level controlled in the other two headings. The manifold exhaust system has proven to be an efficient, long lasting ventilation system at the Alchem Mine. It has reduced the dust and noise exposure levels at the working faces while keeping the methane level under control.

Jan 1, 1980

By Mark K. Larson, Douglas R. Tesarik, Heather E. Lawson

"Load transfer distance (LTD) is simple in concept and usually evident in underground coal mines. Many people in the mining industry recognize LTD as the distance from the panel to where the mine ribs and pillars show evidence of renewed spalling, floor heave, or other effects of increased weight due to longwall mining or pillaring. Barrier pillars, in particular, are designed to shield mains and other relatively permanent facilities from this loading. LTD is also important in determining the extent and degree to which mining increases the load on pillars and ribs in the gate roads. Generally, a long LTD reduces loads in gate roads, but may require larger barrier pillar widths to protect mains or adjacent panels from excessive loads. Therefore, a long LTD may make it easy or difficult to meet various objectives of mine layout design . LTD reflects overburden geology in two ways: First, overburden that is weak and readily caves will limit both the amount and distance of load transfer. Second, stronger, stiffer, sandier, and more massive overburden increases both the amount and distance of load transfer. As such, LTD is central to coal mine layout design and calibration of numerical models that seek to anticipate these transfers of load during mining. However, the term does not have a consistent definition in the literature, and various instruments and observational techniques with varying sensitivities and thresholds have been used to indicate the onset of mining-induced stress increase and, subsequently, to determine an LTD. Consistency is important for meaningful comparison of ground response between mining sites and for accurate calibration of models.This paper adds to the body of observed and reported LTDs by presenting cases with relatively sandy and massive overburden at two western coal mines. These two cases include observation and measurement of LTD with multiple methods and provide insight into how distances reported relative to different criteria and instrumentation could be adjusted for comparison against a common base. This base is the criteria used by Peng and Chiang (1984) to determine their empirical equation. In one of these two cases, LTD was recently measured at a western U.S. coal mine (Mine A) to be approximately four times that calculated using the Peng and Chiang empirical equation. LTD measurements were examined using various instruments at Mine A and at adjacent Mine B. The measurements at Mine B showed that LTD was significantly greater than that calculated by the Peng and Chiang equation. Difficulties with BPC installation and fittings at Mine B permitted only ranges of LTD to be determined from some BPCs. Even so, the LTDs and ranges of LTDs determined were consistent with the LTDs determined at Mine A."

Jan 1, 2015