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By Walter W. Kaufman

The braking performance of underground, rubber-tired, non-coal mining vehicles is evaluated. Surveys of mining equipment and braking manufacturers and underground stopping tests are discussed as they relate to this evaluation. Stopping performance recommendations are included as well as related aspects of roadway construction and runaway vehicle protective devices.

Jan 1, 1977

By E. C. Truesdale, Gerald Edmunds

A few years ago H. M. Cyr, working in the Research Laboratories of The New Jersey Zinc Co., produced a few pounds of zinc1 of such purity that no other elements were detected in it by spectrographic analysis, using the facilities then available. This zinc contained less than one ten-thousandth of one per cent of metallic impurities.&apos; During the decade that followed upon the laboratory production of this "spectro-graphically pure" zinc, commercial developments brought about the production of large tonnages of zinc of purity exceeding 99.99 per cent, and today zinc of 99.999 per cent purity is produced and marketed as "chemically pure" zinc. Typical analyses of present supplies of high-purity zinc are given in Table 1. Table 1.—Typical Analyses Percentnge by Weight Sum of Zinc Fe, Ib1 Fe Cd 1A1 cd Special High Grade*.......... 0.007b 0.005b 0.005b none O.OIOb C.P. (chemically pure)......... < 0.0002 0.0005c 0.000052 S.P. (spectrographically pure).. <0.0002d <0.00005d a A.S.T.M. Standard Specification for Special High Grade Slab Zinc (A.S.T.M. Designation: B 637). b Maximum. &apos; Fe chemically determined. Pb and Cd are spectrographically determined. d Differences between composition of C.P. and S.P. zinc are discussed later in this paper. The availability of commercial tonnages of special high-grade zinc has been the basis for the development of the zinc-base die-casting alloy industry which, in the year 1936, consumed one-eighth of the zinc used in the United States for all purposes. This and the C.P. and S.P. grades have given impetus to scientific investigations into the properties of pure

Jan 1, 1939

By E. C. Truesdale, Gerald Edmunds

A few years ago H. M. Cyr, working in the Research Laboratories of The New Jersey Zinc Co., produced a few pounds of zinc1 of such purity that no other elements were detected in it by spectrographic analysis, using the facilities then available. This zinc contained less than one ten-thousandth of one per cent of metallic impurities.&apos; During the decade that followed upon the laboratory production of this "spectro-graphically pure" zinc, commercial developments brought about the production of large tonnages of zinc of purity exceeding 99.99 per cent, and today zinc of 99.999 per cent purity is produced and marketed as "chemically pure" zinc. Typical analyses of present supplies of high-purity zinc are given in Table 1. Table 1.—Typical Analyses Percentnge by Weight Sum of Zinc Fe, Ib1 Fe Cd 1A1 cd Special High Grade*.......... 0.007b 0.005b 0.005b none O.OIOb C.P. (chemically pure)......... < 0.0002 0.0005c 0.000052 S.P. (spectrographically pure).. <0.0002d <0.00005d a A.S.T.M. Standard Specification for Special High Grade Slab Zinc (A.S.T.M. Designation: B 637). b Maximum. &apos; Fe chemically determined. Pb and Cd are spectrographically determined. d Differences between composition of C.P. and S.P. zinc are discussed later in this paper. The availability of commercial tonnages of special high-grade zinc has been the basis for the development of the zinc-base die-casting alloy industry which, in the year 1936, consumed one-eighth of the zinc used in the United States for all purposes. This and the C.P. and S.P. grades have given impetus to scientific investigations into the properties of pure

Jan 1, 1939

By Robert T. MacMillan

An essentially chemical technique has been developed on a small scale for the efficient utilization of certain domestic titaniferous iron ores. Three main steps are involved: (1) Sintering the ore at 1,050° C. with carbon and soda ash to reduce the iron to metal powder, retaining the titania in the slag, (2) separating the powdered iron from the slag, after wet grinding, by magnetic or gravity methods, and (3) sulfuric-acid decomposition of the titania fraction to produce pigment and certain byproducts. The technique was first applied to the tailings from the Bureau of Mines bauxite-concentrating plant at Bauxite, Ark. A good grade of powdered iron was produced from this material. Subsequently, the work was diverted to the study of the titaniferous magnetite from the MacIntyre Mine at Tahawus, N.Y., because of the potentially higher recoveries of iron, titanium and vanadium. Ninety percent of the iron in this ore has been recovered as an iron powder analyzing 90 percent metallic iron and containing 2 to 3 percent TiO2. The remaining titania was found in the slag and was recovered as pigment-grade TiO2 by application of a suitable technique. The vanadium was distributed between the TiO2 fraction and the alkaline liquor resulting from the wet-grinding and magnetic-separation operations, with only a minor proportion retained by the metallic iron.

Jan 1, 1950

By Leandro Gusmão da Silva

Neste trabalho, foram estudados os efeitos da irradiação de uma superfície polida do aço inoxidável tipo ASTM F138 com laser de pulsos ultracurtos. As irradiações foram realizadas variando-se a velocidade de varredura do laser, ou seja, a taxa de sobreposição espacial de pulsos. Foi observado que após a irradiação houve uma visível mudança na coloração da amostra. Também foi verificado que com o aumento da taxa de sobreposição de pulsos a superfície tendeu a tornar-se preta, ou seja, absorvedora de luz. Com essa técnica, pode-se realizar marcações com alto contraste sem que haja formação de camadas de óxidos, nitretos ou alterações microestruturais no metal, o que é importante para um material com a precisão que um implante exige.

Aug 17, 2017

By B. Andresen, S. T. Johansen, H. Tveit, S. Grådahl, B. Ravary

The Norwegian ferroalloy industry has high ambitions regarding environmental standards. Basic research work has been performed to improve the fundamental understanding of ferroalloy processes and the environ-mental aspects. This paper will present work dealing with the understanding of formation and control of NOx, PAH and dioxins. During this work various techniques and methods have been applied, such as comprehensive industrial measurements, laboratory experiments, model development and application of Computational Fluid Dynamics (CFD). The main goal has been to reduce the environmental impact of ferroalloy plants, by means of improving the combustion processes done by introducing new charging routines and optimized furnace operations, instead of installing expensive gas treatment systems. The Norwegian obligations in accordance with the Gothenburg protocol are to reduce the NOx emissions by 30%, compared with the 1990 level within 2010. Measures developed in this work have resulted in 40-60%reduction in NOx emission, and major reductions in PAH and dioxins for ferrosilicon and silicon metal plants. This has been achieved by introducing semi continuous charging and improved furnace operations. Semi continuous charging and optimized furnace operations are shown to reduce the blowing activity (i.e. emission of large quantity of SiO over the charge by direct channelling from the crater zone). It also reduces variation in off-gas temperature and dust production. To understand the processes and to achieve our results we have used online equipment, with fast sample rates and response times, to measure the off-gas compositions and temperatures. Most of the measuring techniques used are based upon optical principles making use of the absorption- and emission spectrum of the gases. In addition a new prototype instrument is developed for continuous measurement of off-gas characteristics, total dust amount and off-gas temperature. The presented work is a result of a long term co-operation research and development teamwork, between the industry and the research community, and has improved both the process and reduced the emissions. The work has introduced new process design and operation standards, and has resulted in ferroalloy production with better environmental standards.

Jan 1, 2007

By Dorothy M. Richardson

The Bureau of Mines has participated in the American Petroleum Institute Research Project 48A (API-RP48A) program on the Separation and Identification of Sulfur Compounds in Crude Petroleum. The lack of reference compounds or infrared spectral data has made difficult the identification of individual sulfur compounds boiling above 140° C. The recent acquisition of 24 alkylthiophnnes has made possible a limited study of this important class of sulfur compounds. The infrared spectra of 2-monoalkylthiophenes and 2,5-dialkylthiophenes for the 2 to 15p range are reported. Correlations for determining the 2-alkyl and 2,5-dialkyl substituted thiophenes are derived from this information. The 2-alkylthiophenes show a unique pattern in the 5.50 to 6.54 region, while the 2,5-dialkylthiophenes show a distinctive pattern in the 5.6µ to 6.7µ region. A skeletal vibration occurs in the 9.5 to 10.0µ region for all of the thiophenes investigated. These data will aid the infrared spectroscopist in the identification of compounds of the type reported.

Jan 1, 1961

According to the data provided by the most recent European Survey on Working Conditions, roughly 25 per cent of the European working population is exposed to mechanical vibrations for no less than one quarter of the work shift duration, while around ten per cent are exposed for the entire work shift. The occupational exposure to whole-body vibration (WBV), in particular, represents a major health risk in mining, quarrying and civil excavation activities. In accordance with European Directive 2002/44/EC, the latest version of the Italian law on physical risks has recently confirmed the possibility of using relevant literature data on vibration magnitude in order to evaluate personal occupational exposure (vibration database or data provided by the manufacturer). Still the alternative option, based on field measurements, represents the most appropriated method of risk assessment, as it accounts for the actual operating condition at the workplace; actual operator and vehicle under investigation and specific working cycle. The article discusses the vibration measurements taken on a number of heavy machinery (excavators, loaders, trucks, dumpers, etc) employed for talc extraction in a mine located in Sardinia and the resulting personal exposure for the drivers. The assessment was carried out in accordance with the specifications of ISO 2631-1 and EN 14253.

Dec 6, 2010

By G. L. Oldright

The studies previously made on Smelting in the Lead Blast Furnace have dealt with the custom smelter of the International Smelting Co. at Tooele, Utah, and on the smelter of the Bunker Hill & Sullivan Mining & Smelting Co. at Kellogg, Idaho. The International plant may be considered representative of the traditional custom smelter. The lead smelter of the future seemingly will have to treat increasingly richer lead charges. This feature was then stressed in describing the Bunker Hill plant.

Jan 1, 1934

By Heidy de Oliveira Simões

Visando entender os impactos causados pela formação de trincas e deformação das pelotas na qualidade física do material, foi desenvolvido um algoritmo que, através de análise automática de imagens, é capaz de medir o tamanho da trinca, sua largura e comprimento, bem como efetuar as medições de tamanho e morfologia da pelota queimada. Foram analisadas pelotas produzidas com minério hidratado (elevado teor de goethita) com 2 perfis térmicos distintos. Os dados obtidos na análise de imagem foram correlacionados com a resistência à compressão das pelotas e evidenciaram o tamanho das trincas denota notória correlação com a sua resistência física. A medição das trincas formadas pela deformação da pelota no leito (denominadas resiliência) permite evidenciar o quanto a pressão no leito de pelotas impacta na qualidade após a queima, bem como indica o ponto ótimo para que não acarretem em perda da resistência. A medição do tamanho das trincas térmicas mostra-se essencial, pois mesmo em perfis mais suaves de queima pode haver a formação de tais trincas, sendo que o tamanho e a abertura da trinca é que definem a melhor ou pior resistência. O conhecimento, e possível aplicação prática, da avaliação das trincas poderá auxiliar na otimização de perfis térmicos de fornos de pelotização.

Aug 16, 2017

By E. A. Schmidt

In 1962, while investigating the tungsten potential in the Thompson Creek area for Union Carbide Corp., Henry T. Eyrich obtained anomalous concentrations of molybdenum (up to 19 ppm Mo) from stream sediment samples collected along Pat Hughes Creek, a tributary to Thompson Creek. Follow-up investigations by Eyrich during the same year disclosed the presence of a hydrothermally altered and molybdenite-bearing granitic exposure in the headwaters of Pat Hughes Creek about 2.4 km (1.5 miles) upstream from the sample point. The altered outcrop measured about 549 by 305 m (1800 by 1000 ft), contained abundant northwest-trending quartz veins locally with molybdenite, and was overlain and surrounded by the Challis volcanic extrusive sequence of mid-Tertiary age. Eyrich&apos;s subsequent soil and rock chip geochemical sampling program over the altered outcrop area showed a general increase in the molybdenum content to the northwest toward the postmineral Challis volcanic cover. Over a distance of about 305 m (1000 ft), values in the altered intrusive rock increased from less than 5 ppm Mo to over 600 ppm Mo, with aconcomitant intensity of the hydrothermal alteration pattern. Based on these geochemical results and on preliminar; megascopic hydrothermal alteration studies, Eyrich correctly concluded that the altered outcrop is an erosional window and that molybdenum mineralization of sufficient grade could exist beneath the Challis volcanic cover some distance further to the northwest. His recommendation to test the area of potential molybdenum mineralization with several drill holes was, however, declined by Union Carbide in 1962. The property remained unclaimed until 1967, when Eyrich joined Cyprus Mines Corp. Acting on Eyrich&apos;s recommendation, Cyprus immediately staked 26 lode mining claims to cover not only the altered intrusive outcrop, but also the northwest trend of mineralization where it projected beneath Challis volcanic rocks. Eleven of these claims are now patented.

Jan 1, 1991

By William S. Heckman

a. When to use: high surcharges, vertical capacity required, limit noise and eliminate vibrations, low headroom, eliminate vibration induced settlements. b. Advantages: eliminates impact noise and vibrations, high section modulus if required, vertical load bearing capacity; corrosion resistant, easy to apply facing for use as a permanent wall, adapts to complex wall layouts, would allow top- down construction, very high uplift resistance. c. Disadvantages: spoil disposal, not water tight, cannot penetrate rock and most obstructions, soil can erode between the piles if surface water and ground water are not controlled, hard to install reinforcing beams over 409 long; subject to high negative skin friction loads, high grout takes in rubble and organic soils. e. Relative cost to other systems: 30% to 50% more expensive than driven soldier piles and lagging except when surcharge loads are involved, or the pile cannot be driven due to noise and vibrations. About the same cost as a sheet pile system. Very competitive if high vertical load must be supported by the wall.

Jan 1, 1997

By Jelena Milinovic, Sofia Martins, Anna Lichtschlag, Sven Petersen, Fernando J. A. S. Barriga, Bramley Murton, Adeline Dutrieux

"The active TAG hydrothermal mound is one of the largest and better studied. Due to its size (one of the largest, known so far, in the Atlantic Ocean) and concentration of specific economic valuable elements, it might be considered for future exploitation due the increasing demand for raw materials. However, the discovery of several large inactive sulfide mounds, some partially buried under sediments may relieve this pressure. Exploration for such occurrences can, together with geophysical exploration tools, be accomplished by mineralogical and geochemical studies of those sediments.INTRODUCTION AND GEOLOGICAL SETTINGThis study reports the results from sediment samples collected during the Meteor M127 cruise on the TAG hydrothermal area in 2016. The Trans-Atlantic Geotraverse (TAG) hydrothermal field (Mid-Atlantic Ridge, 26°08’N) is located 2.4 km east of the main rift valley at depths of about 3650 m. The TAG hydrothermal field stands as an example of a massive sulfide deposit on a low-spreading ridge associated with an active detachment fault (Humphris et al., 2015).Associated with the TAG hydrothermal field are metalliferous sediments/deposits that can reach several meters in thickness (Metz et al., 1988). These sediments/deposits can be formed by hydrothermal plume fall out (buoyant and nonbuoyant), massive wasting of hydrothermal edifices (sulfide mounds and chimneys) and authigenic mineralization (Gurvich, 2006). By studying the grain size, mineralogy and geochemistry of the sediments it is possible to identify each type of sediments and find their proximal or distal distribution. The location of the gravity cores studied here is distributed along sediment ponds near inactive hydrothermal mounds [Three mounds area (B)], actively venting low-temperature mound [Shimmering mound (A) and Mir zone (D)] and an area of sediment accumulation [Central area (C)] (Rona et al., 1993) (see Figure 1)."

Jan 1, 2017

By H. Soto, J. Jara, F. Nava

"A combination of oxidation and precipitation was used to eliminate cyanide from gold milling effluents. Preliminary laboratory work developed with both synthetic cyanide solutions and with industrial effluents indicated that ozone can easily destroy free cyanide and weakly complexed cyanide (i.e. copper and zinc cyanide). In this case the reaction is quite fast and seems to be controlled by the mass transfer of ozone to the solution. Experimental results indicate that free cyanide and weak-acid dissociable cyanide in mill effluents can be reduced to less than 1 ppm. However, the iron-cyanide complexes proved to be quite resilient to destruction with ozone and they remained in the solution even after most of the free and weakly complexed cyanide was destroyed with ozone. These results were confirmed in a pilot trial developed at the Sphinx plant in northern Quebec.To deal with the problem presented by the presence of the iron complexes two different approaches were studied: use of a combination ozone-ultraviolet light oxidation, and the precipitation of iron-ferrocyanide complexes in the residual solution after ozonation. This last method proved quite promising since reduced the total cyanide levels of industrial solutions assaying as much as 250 ppm to less than 1 ppm of total cyanide. Control of the · pH of the solution was the key to obtain the precipitation of the iron complexes. The use of iron to precipitate cyanide complexes has the advantage of being less expensive and less toxic than copper (used by the Inco process)."

Jan 1, 1992

By J P. Jona, S R. Poulson, C H. Gammons

Spatial and temporal trends in water chemistry in the acidic (pH ~2.6) Berkeley Pit lake, Butte, Montana, can be explained by a newly developed iron-cycling model. Key elements of this model include: subaqueous oxidation of pyrite and other metal sulfide minerals by dissolved ferric iron, producing Fe2+ as a by-product; re-oxidation of Fe2+ to Fe3+ in the epilimnion, assisted by A ferrooxidans; precipitation of secondary ferric minerals (schwertmannite, jarosite) in the epilimnion; and replenishment of the Fe3+ concentration of the hypolimnion by seasonal lake turnover and gravitational settling and re-dissolution of ferric precipitates. Pyrite oxidation rates were approximated by using published rate laws and information on the Fe3+ concentrations (~5 mmol) of the Berkeley Pit as a function of depth. The results indicate that subaqueous pyrite oxidation may be releasing as little as 6 + 106 or as much as 600 + 106 moles of H+ each year to the lake; the large range reflects uncertainty in calculation of the specific surface area of pyrite in the flooded pit. This helps to explain the observation that the pH and metal concentrations of the Berkeley Pit have not improved with time since mine flooding began in 1983. Vertical cycling of ferric iron in the pit lake permits pyrite oxidation to continue in deep water, even in the absence of dissolved oxygen. This hypothesis is supported by preliminary stable-isotope data.

Jan 1, 2003

By Fredrick M. Ryan

Present indications are that in about 2-3 years phosphor tags will be required in commercial explosives. A permissible 254 run ultraviolet lamp assembly has been developed to permit mine inspectors to detect such phosphor tags and therefore to establish if non-permissible explosives were used. This new lamp is powered by a Miner&apos;s cap battery without interference with the normal lighting requirements of the cap lamp battery. It is compact, light, and rugged with very high ultraviolet output.

Jan 1, 1977

By P. Quinn

"The Venturi-aerated flotation column (VAC) is based on a reactor and separator design for a new generation of flotation machines. The reactor is a Venturi tube, where the air/slurry contact takes place with intensive aeration for efficient particle collection. The separator is a column of 1-3 m length that provides quiescent hydrodynamic conditions for effective separation of bubble-particle aggregates from the remaining slurry.Aeration in the Venturi tube occurs via two mechanisms: air dispersion and nucleation (cavitation). By forcing air through a restricted passage with a fast flowing slurry stream, air is dispersed into fine bubbles. Bubble formation due to cavitation occurs on the surface of particles in the low-pressure section of the Venturi, from dissolved air contained in the liquid.Size-by-size recovery and flotation rate constants were determined for a small-scale laboratory Venturi-aerated flotation column. The results were compared to those obtained in a laboratory 2.2 L Denver cell. It is shown that the Venturi-aerated flotation column has slightly slower flotation kinetics to the Denver cell, but with much higher flotation selectivity. A portable Venturi-aerated flotation column can effectively be used to investigate process or equipment problems in operating plants.INTRODUCTIONFlotation processes can generally be divided into two sub-processes: 1) selective collection of hydrophobic particles by air bubbles and 2) separation of bubble-particle aggregates from hydrophilic particles that remain in the pulp. The methods of aeration, or bubble generation, control the mechanism of particle collection by either collision with, and subsequent attachment to bubbles, or by in situ bubble formation on the surfaces of hydrophobic particles. A flotation device should provide optimal aeration conditions for efficient particle collection and a suitable hydrodynamic environment for effective removal of bubble-particle aggregates from the remaining pulp."

Jan 1, 2002

By B. N. Hira

A multistoreyed residential complex was at the penultimate stage of construction by ONGC at Nazira, Assam. The site was situated at high earthquake zone. The subsoil was very weak and contained soft to medium clay with water table almost at the ground level. The bearing capacity of soil was quite poor particularly with predicted settlement beyond permissible limit. In this situation, the conventional shallow and deep foundations were found uneconomical and ground improvement with granular piles was considered as the viable solution. ONGC approached the Central Building Research Institute with the request to design granular piles along with R.C.C. foundation and other suitable cost effective measures. CBRI collected relevant geotechnical informations and supplimented the data by conducting field tests at site and laboratory tests at Roorkee. Rational design of 30 cm dia. and 5.00 meter deep granular piles were suggested with isolated and combined RCC footings over the reinforced soil. In addition to several structural and geotechnical advantages, the granular pile foundation provided considerable economy in the cost of construction. The paper presents the salient geotechnical and structural informations of the challenging project and provides the design details of the innovative granular pile-system. It also furnishes the design approach of the RC footings and other elements of the foundation.

Jan 1, 1996

By Walter W. Bradley

FOR a number of years up to the economic setback of the 1929-1931 period, the greatest proportional advances in the mineral industries in California were made among the substances in the nonmetallic groupings, particularly among the so-called industrial minerals and the salines. During the past year or two, although these have not regained the stride that marked their progress in the preceding decade, we can still record, -some new developments. California produces annually between 55 and&apos; 60 different minerals on a commercial scale. Of these, some 40 to 45 comprise the "structural," "industrial," and "salines" materials as grouped in the reports of the State&apos;s Division of Mines. Barite-The barite deposits of California were described in Report

Jan 1, 1935

By R. J. Hundhausen

This report describes the exploration and recent utilization studies the Bureau of Mines conducted on the Iron King, Chambers, and Dry Camp chromite deposits in the John Day district, Grant County, Oreg. The field investigations were undertaken during parts of 1939 and 1942 to determine the tonnage and grade of chromite in the district that could be utilized as a war reserve for the steel industry. As a result of the Bureau&apos;s field work, which included construction of 9 miles of access road, 6,204 feet of diamond drilling, 195 channel samples, and 1,020 linear feet of trenching, an ore reserve of 208,000 tons of 22-percent chromic oxide was indicated in the 3 deposits. Less than 1,000 tons of this ore has been mined since the field work was completed because the 2 largest deposits are submarginal in grade and there is as yet no incentive to develop and mine the ore. Since the war, however, the Bureau has been seeking means of utilizing the ore. Two methods of utilization that show promise are direct smelting of the ore in an electric furnace and use of the chromite for making refractory brick.

Jan 1, 1956