Search Documents

By C. G. Anderson

Throughout the world, there are many orebodies or materials which have significant value but also contain arsenic. As regulations on the transport, exposure, disposition and emission of arsenic have become more stringent; it has become increasingly more difficult to derive the values from these resources. This paper will outline the fundamentals of alkaline sulfide hydrometallurgy and its successful application to arsenic bearing ores, concentrates and materials.

Jan 1, 2005

By Zay Jeffries

J. W. RICHARDS, South Bethlehem, Pa.-I think that the diagrammatic results can be much more clearly set forth if they are plotted as follows: The present diagram, shown on page 1227 of Mr. Jeffries' paper, Logarithm of Per cent of Maximum Wattage Used plots the variation of wattage with temperature in a very inconvenient and uncertain-way. If, however, you plot as abscissas the logarithms of the wattage, you get very nearly a straight line, so that you can interpolate the values with much greater accuracy than you can by using

Jan 4, 1917

By R. Watts, R. A. Laybourne

This paper describes how a 'mined out' coalfield is being mined successfully by opencast methods. The coalfield is that at New Vaal Colliery, which is situated in the Vereeniging-Vanderbijlpark-Sasolburg industrial complex. Al three coal seams at New Vaal had been mined previously, when the better-quality coal had been removed. The coal-preparation plant at New Vaal, which is also described, supplies coal to the 3600 MW Lethabo Power Station. The Colliery has been designed to supply 600 million sales tons of coal over its forty-year life.

Jan 1, 1990

By Cowie WJ, Utting BS

The alluvial gold industry of New Zealand is based on the placer deposits in Otago and on the West Coast. Production from these since discovery in the 1850's has been an estimated 480 tonnes (15 million ounces) of gold. Annual output has expanded continuously since 1980 and is expected to be over 2 tonne of gold for 1989.Following a historical review, the characteristics of typical operations, which use hydraulic excavators and mobile trommel units are discussed. Descriptions are then given of alluvial activities in Otago and on the West Coast.

Jan 1, 1990

By R. Debkowski

Mining methods used to protect the workings in underground salt mines against the destructive activity of natural factors are presented in this paper. Major hazards and methods of elimination of their impact on the stability of workings, were determined. Old and modern technical means and technologies used for protection and preservation of the selected most interesting sites were characterized. The results of surveys and studies allowed proposing the change of mine structure i.e. dividing it into monumental and not-monumental part, which should improve execution of necessary protective works.

Jan 1, 2006

By Payman Roonasi

Having knowledge of mechanism of magnetite formation is essential in a number of industrial processes including magnetite synthesis and corrosion of iron. In this study, magnetite nanoparticle was synthesized via two different ways; coprecipitation of iron (II) and (III) and oxidation of ferrous hydroxide. The samples were characterized using X-ray diffraction (XRD), Mid-Far IR spectroscopy, scanning electron microscopy (SEM), chemical analysis for determination of Fe II/Fe III ratio and ICP-MS for iron isotopic ratio (56Fe/54Fe) measurement. Since fractionation of iron isotopes depends on reaction rate and bonding strength, interpretation of the isotopic data with respect to the possible mechanisms is discussed. No fractionation of iron isotopes was observed for the magnetite synthesized by coprecipitation, whilst magnetite formed from ferrous hydroxide showed higher abundance of 54Fe compared to 56Fe in the beginning of reaction, implying the significance of the following reaction:

Jan 1, 2009

By S. M. Moore

Each year more than 400 coal miners are injured (fatal and non-fatal) by rock falling from between or around roof supports. Many of these injuries could be prevented by the installation of roof screen (wire mesh). However, many coal mines may be reluctant to use roof screen because of the added cost. The goal of this study was to determine the potential saving in workers? compensation (WC) premiums that could be achieved due to a reduction in rock fall injuries after roof screening. The WC rate-setting methods utilized by IL and KY were investigated in this study. Using actual data obtained from MSHA, national and state WC bodies and individual insurance companies (e.g. average cost per injury, loss cost rate, number of injuries per year, number of injuries preventable each year with roof screening), hypothetical mines (representing two mine sizes: 67 and 150 employees) were constructed with realistic ranges for estimates of injuries and WC premium costs. Using each state?s actual WC rate-setting formulas, total savings in WC costs after a three-year period were determined. Across both states, savings in WC premiums ranged from 1.8% to 14.6% when injuries were reduced by 10% to 20%. Additionally, an economic analysis was performed for an existing mine consisting of 67 employees. For this mine, the annual cost of a roof screening program was estimated at $240,000. If the screening prevented 13 ?struck by? WC claims over a 3-year period at this mine, the reduction in WC premiums alone could pay for the entire screening program.

Jan 1, 2010

By A. J. Hendron, G. Mesri, R. M. Semple

Squeezing ground conditions in hard-rock tunneling are associated with fault zones containing brecciated rock and gouge. Gouge is a stiff clay-like soil that exhibits a propensity to creep. The ground loads applied to tunnel supports in squeezing ground are known to be significantly time dependent. Accordingly, an experimental and analytical study is presented that deals with soil creep and its application to the prediction of tunnel support requirements in squeezing ground conditions. Relatively undisturbed samples of fault gouge obtained from Straight Creek tunnel in Colorado and Pacheco tunnel in California are classified as very stiff to hard clays of low plasticity. Constant-load undrained triaxial compression tests are performed on these materials. A simple, three-parameter creep equation is developed that adequately describes the observed deformation of fault gouge with respect to applied stress and time. The equation is shown to fit existing creep data of various soil types. The creep equation is used to modify an existing continuum-mechanics solution to the time-dependent behavior of unlined and lined cylindrical openings in a creepsensitive medium under a hydrostatic state of stress. Assuming properties for the medium that are representative of the fault gouge materials tested, parameter studies are performed for unsupported and supported tunnels in squeezing ground. The analyses permit estimates to be made of the steel set supports required for tunnels at different depths in various squeezing ground conditions.

Jan 1, 1974

By C. F. Kaiser, T. J. Roberts, I. A. Thomson

The Broken Hill Pty. Co. Ltd. grate-kiln pelletizing plant located at Whyalla, South Australia, produced a total of 250,000 tons of fluxed pellets during 1970. More than 180,000 tons were exported to Japan, while the remainder was used in B.H.P. Co. blast furnaces. The pellet plant treats high grade hematite ore fines and has a nominal capacity of 1.5 million tpy. The induration equipment includes a grate 12-ft 2-in. wide by 164-ft 1-in. long, a kiln 18-ft 6-in. diam by 118-ft 8-in. long, and a rotary cooler 50-ft mean diam by 7 ft wide. Operating problems encountered in the production of fluxed pellets are detailed. The most significant aspect of the trial was the increased production, from about 5100 tpd up to a maximum of 7100, brought about by the addition of artificial magnetite to the plant feed. Laboratory evaluation of fluxed pellets showed that pellets having a basicity ratio (CaO to SiO2) in excess of 1.2 have excellent physical qualities. Reducibility and compressive strength after reduction were both higher for these fluxed pellets than for normal acid pellets. Although it was not possible to publish blast furnace operating data, blast furnace trials on fluxed pellets indicated that production was higher and dust losses substantially lower, compared with similar operations on acid pellets.

Jan 1, 1973

By Kurt Bryan, O&apos

The crushing and milling of mineral bearing ores can now be accomplished more efficiently through the application of WaterFlush technology. WaterFlush crushing has reduced capital and operating costs for the processing of a lead/zinc ore in South America. Similar benefits can be expected in the processing of other ores. WF cone crushers offer improved performance over conventional cone crushers. Performance improvements include the ability to crush wet and sticky ores, increased reduction ratios and greater production of flakier and finer products.

Jan 1, 1989

By D. W. Frommer

Mineral dressing research was conducted by the Federal Bureau of Mines under a cooperative agreement with the St. Joseph Lead Co., on three samples of iron ore from the Pea Ridge deposit in central Missouri. The objective was to provide information on how to upgrade these submarginal ores and produce marketable concentrates. Samples were prepared from drill-hole cores of similar composition and character to produce (1) a medium-grade mixed hematite and magnetite, (2) a high-grade mixed hematite and magnetite, and (3) a high-grade magnetite. In all three ores phosphorus and sulfur constituted objectionable impurities; excessive amounts of silica were also present in the medium-grade ore.

Jan 1, 1960

By Gary B. Glass

Seventeen percent of US coal production now comes from the 19 surface coal mines in the Powder River Basin of northeastern Wyoming. The Powder River Coalfield, which coincides with this topographic and structural basin, is unique to the conterminous US, in that it contains an estimated 934.4 Gt (1.03 trillion st) of in-place coal resources. At least 13.2 Gt (14.6 billion st) is a compliant, strippable reserve base. In 1993, an estimated 162 Mt (179 million st), or 98% of the coal mined in this Wyoming coalfield, came from the thick - average 30.5 m (100 ft) - subbituminous, Wyodak coalbed, or from the Anderson and Canyon coals in the one mine where the Wyodak is split into two separate coalbeds. The other 2.7 Mt (3 million st) of coal mined in the Powder River Basin in 1993 came from the School, Badger, Monarch and Deitz No. 3 coalbeds. In this "world class" coalfield, there are at least 13 other persistent, 3 to 15 m (10 to 50 ft) thick, coalbeds as well as the Big George and Lake De Smet coalbeds, which are each 61 m (200 ft) or more thick in places. None of these latter 13 coals are mined at this time.

Jan 1, 1994

By J. R. Linney

A HISTORY of the ore-mining and iron-smelting industry of the Adirondacks comprises a century and a half of pioneering by rugged individualists, both men and women. By geographical location, the climate is most severe-long, cold winters with heavy snowfall, and short seasons of vegetation growth; this, together with its remote location from large centers of population, adds considerably to the difficulties of conducting mining operations in this area.

Jan 1, 1943

By Peter M. Fozzard

A review is made of the actual costs of recent foreign mineral exploration programmes in third world countries. Target identification leading to the selection of areas, or macro-targets, must follow a well planned and defined series of steps. Suggestions are made with respect to this inter-active project development work. Potential revenues in the broad sense will always determine the overall economics of exploration but clear objective philosophy, good planning and adequate financing are essential for exploration success. Considerable opportunities exist for making important foreign mineral discoveries and broad selected suggestions are made for the identification of exploration areas in relation to high-grade and precious metal mineralization.

Jan 1, 1984

Minerals are vital to any industrialized civilization. Annually, the United States uses more than 4 billion tons of new mineral materials, or about 40,000 pounds per person-about half being mineral fuels and the other half being metals and nonmetallics. Stable and economic domestic mining, mineral, metal, and mineral reclamation industries are essential to the economy. The value of United States energy and processed materials of mineral origin exceeds $200 billion annually. Although a number of minerals are imported, especially some designated as "strategic and critical," most U.S. mineral supplies are derived from the domestic mines and processing facilities that you will be seeing, reading about, and visiting as you use this visitor guide. We hope you enjoy your experiences. This pamphlet, a guide to mining and mineral operations that may be observed or visited and some other points of interest relating to minerals, is in-tended to aid tourists and students who are interested in mining. Some may wish to study our Nation's romantic past; others may plan to enter the minerals industry as a career; still others may have a primary interest in conservation practices. The pamphlet is also intended to aid State and local officials, Chambers of Commerce, and mining firms in answering some of the many questions of tourists and students.

Jan 1, 1977

Minerals are vital to any industrialized civilization. Annually, the United States uses more than 4 billion tons of new mineral materials, or about 40,000 pounds per person-about half being mineral fuels and the other half being metals and nonmetallics. Stable and economic domestic mining, mineral, metal, and mineral reclamation industries are essential to the economy. The value of United States energy and processed materials of mineral origin exceeds $200 billion annually. Although a number of minerals are imported, especially some designated as "strategic and critical," most U.S. mineral supplies are derived from the domestic mines and processing facilities that you will be seeing, reading about, and visiting as you use this visitor guide. We hope you enjoy your experiences. This pamphlet, a guide to mining and mineral operations that may be observed or visited and some other points of interest relating to minerals, is intended to aid tourists and students who are interested in mining. Some may wish to study our Nation's romantic past; others may plan to enter the minerals industry as a career; still others may have a primary interest in conservation practices. The pamphlet is also intended to aid State and local officials, Chambers of Commerce, and mining firms in answering some of the many questions of tourists and students.

Jan 1, 1977

Minerals are vital to any industrialized civilization. Annually, the United States uses more than 4 billion tons of new mineral materials, or about 40,000 pounds per person-about half being mineral fuels and the other half being metals and nonmetallics. Stable and economic domestic mining, mineral, metal, and mineral reclamation industries are essential to the economy. The value of United States energy and processed materials of mineral origin exceds $200 billion annually. Although a number of minerals are imported, especially some designated as "strategic and critical," most U.S. mineral supplies are derived from the domestic mines and processing facilities that you will be seeing, reading about, and visiting as you use this visitor guide. We hope you enjoy your experiences. This pamphlet, a guide to mining and mineral operations that may be observed or visited and some other points of interest relating to minerals, is intended to aid tourists and students who are interested in mining. Some may wish to study our Nation's romantic past; others may plan to enter the minerals industry as a career; still others may have a primary interest in conservation practices. The pamphlet is also intended to aid State and local officials, Chambers of Commerce, and mining firms in answering some of the many questions of tourists and students.

Jan 1, 1976

By Charles Zdazinsky

"The Multiple Seed Waveform (MSW) blast vibration model, a type of waveform superpositionmodeling developed by Orica Inc., uses vibration data that is collected from a signature hole blast tocharacterize the ground’s seismic properties and determines the ground resonant frequency andfrequency range that is well supported by the ground. Additionally, the MSW model uses thisvibration data as input parameters to predict the resultant dominant frequency of a production blast. This information may in turn be used in conjunction with precise timing control to target theoptimum dominant frequency which promotes ground control."

Jan 1, 2016

By Richards J. W.

J.W. RICHARDS, South Bethlehem, Pa. (communication to the Secretary?).-Mr. Howland's paper, data and conclusions have interested me intensely, and have led me to study carefully the record-of his 26 furnaces therein given. Mr. Howland is undoubtedly right in his conclusion that when expressing the amount of carbon burned at the tuyères in percentage of the total

Jan 1, 1917

By Frank Sames

Most Blasting Programs are developed focussing on the environmental impact with respect to blast vibration and airblast. Compliance with existing regulations or policies limiting the immissions are generally achieved through constrains in the blast design, or monitoring programs. Efficient monitoring programs combine compliance monitoring and blast assessment. Signals, which are obtained in the area of direct influence of the seismic source, can contain valuable information about the blast design parameters. Techniques to analyze blast vibration signals have advanced and can assist in understanding the contribution of individual blast parameters to blast vibration and airblast. Advanced signal analysis encompasses magnitude analysis, Fast Fourier Transforms (FFT) and frequency scans in the frequency domain, as well as filtering in the time domain. Through examples, the advanced signal analysis techniques and their limitations are described and discussed, showing the impact of blast timing, timing accuracy, charge configuration and the geology dependent transmission behavior. Optimization criteria and pragmatic monitoring programs can be developed on the basis of the most influential blast parameters. In addition, however, safety and the cost efficiency of the blasting program are essential to the success of an operation. That is where advanced signal analysis techniques can interface with blast planning, computer assisted modeling and information systems. A valuable process can be developed to ensure compliance with existing regulations and efficient risk management for mining operations, while tracking cost and supporting operational decisions. A conceptual blasting information system is presented.

Jan 1, 2000