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By Thomas J. Peters

In 1979 and 1980, the U.S. Bureau of Mines and U.S. Geological Survey conducted a mineral survey of the 15,600 acre (6,310 ha) Freel Peak RARE II area (No. 5271) in the Lake Tahoe Management Unit. This study by the Bureau of Mines indicates that potential for economic mineral resources in the area is slight. The only mineralized structures in the area consists of two quartz veins. One quartz vein, at the Mountain Top Mine (fig. 1), located by Fred Denner in 1932, is estimated to contain 2,000 tons (1,800 t) of silver and copper-bearing resources. Chip samples from the vein averaged 0.61 oz silver per ton (20.91 g/t), and 1.59 percent copper. The narrow vein is not economically mineable. The other quartz vein is poorly exposed and contains traces of molybdenum. A second reported molybdenum occurrence could not be substantiated.

Jan 1, 1982

This paper examines the reform of mining legislation over recent years, the establishment of new Crown land management agencies, and the role of the Crown and environmental groups in nature conservation inNew Zealand. It describes the relationship of the minerals industry to the Department of Conservation and environmental groups over recent years, and the prospects for mineral development on the Conservation Estate in future.

Jan 1, 1995

By Donald S. Colby

This Bureau of Mines report is essentially a handbook, or manual, for making the type of mineral resource valuation commonly required for such public policy problems as mineral leasing. The principle of resource valuation through the capitalization of cash flow is well established. A mathematical procedure, based on a simplified accounting system, is detailed for calculating cash flow from revenue, plant costs, and operating expense. Variations of procedure cover cost depletion, percentage depletion, and depletion limited to 50 percent of net income. The influence of the depletion provisions of the tax regulations on the value of a resource to an owner and to an operator is analyzed. The relationship of royalty, bonus payments, and sales price to resource value is also described, and methods for approximating resource values using these payments as input data are developed.

Jan 1, 1969

By Stephen R. Iverson

Manganese deposits exist in the Wonder Mountain RARE II area (fig. 1). The manganese mineral is primarily bementite, a silicate. It occurs with Jasper and manganese oxides in tabular or irregular lenses along the contact between red limestone and basalt. There are about 11,000 tons (10,000 t) of indicated sub-economic resources in the northeast part of the study area. Of this, 10,700 tons containing 27.1 percent manganese is at the Apex Prospect and 300 tons averaging 24.8 percent is at the Brown Mule Mine (fig. 1). Another 1,000 tons (900 t) containing 27.0 percent manganese is at the Steel Creek deposit 0.5 mi (0.8 km) west of the area (Wiebelt, 1942, p. 1, 2). Each of these deposits is subeconomic due to small tonnage and high estimated recovery costs. They are in a regional belt of manganese occurrences trending northwesterly through the area. Pardee (1921) reports that manganese ore was shipped from the Triple Trip (Brown Mule) Mine in 1916.

Jan 1, 1982

By Walter Durst

On October 16, 1978, the Harnback open cut of Rheinische Braunkohlenwerke, the largest open cut ever planned, was officially put into operation. It will outperform all of the large open cuts known at present, both in its dimensions and in its annual output of overburden and coal. Present plans are to commence coal mining in 1983, although target production will only be achieved in 1995when the annual output will be 50 million tons of coal. Considering an overburden: coal ratio of 6: 1, this will involve the removal of approximately 300 million bank cubic metres of overburden. For overburden removal and coal mining, this open cut will use bucket-wheel excavators exclusively. It is planned to employ eight excavators with a daily output of 240,000 bank cubic metres each (Fig. 1). The transport of the overburden and coal to the dump and the power station, respectively, will be effected by 30Q0-mm-wide conveyors, running at a speed of 6 m/sec. The overburden will be dumped by spreaders having a boom length of 100 m, capable of dumping 240,000 bank cubic metres per day (Fig. 2). Such giants, of course, can only be used for extreme conditions . Their employment indicates that huge quantities of material can be handled economically for long periods. However, the use of bucket-wheel excavators is economic when daily outputs of 5,000 bank cubic metres are involved, in particular if direct backcasting of the overburden is not possible.

Jan 1, 1979

By Robert S. Nichols

Fording Coal Limited's mine in the Rocky Mountains near Elkford, B.C. has produced 21.8 million clean tonnes of metallurgical coal from 1971 to 1980, inclusive. This production has come from several pit areas and required the removal of 149.1 million bank cubic meters of waste rock and overburden by truck-shovel and dragline operations. Waste dumps from 30m to 200m in height have been successfully constructed on natural slopes, generally between 10° and 26°. Design considerations for the dumps include foundation and soil conditions, natural slope angles and containment of weak overburden or rehandle materials. Dump control is maintained by monitoring the crest and the face of an active dump area. Crest movement is measured by extensometers locally termed "Spoil Monitors". When crest movement rates progressively increase above normal, dumping operations are temporarily relocated. Some unstable conditions and mass failures have occurred as the result of natural foundation slopes being in excess of 26°, failure of weak water saturated foundation soils or weak material being placed on the dump.

Jan 1, 1983

By Roy J. M. van Lier

In industrial aqueous solutions, germanium generally occurs in trace amounts amid high concentrations of other metals, such as zinc, copper and iron. Separation of germanium from these metals as well as its isolation from gallium and indium pose a real challenge to the hydrometallurgist. After a brief discussion of the aqueous chemistry of germanium, this paper reviews the flowsheet of the Apex Mine in Utah. The Apex property was the only mine in the world to be operated primarily for production of gallium and germanium, but apparently closed due to great operating difficulties. Several process variants proposed for the treatment of the Apex ore, including bioleaching methods, are addressed. Following a more general description of the behavior of germanium in hydrometallurgical zinc processing streams, available technology for its recovery from aqueous solutions is summarized. Precipitation, solvent extraction, ion exchange, electrowinning, ion flotation and liquid-membrane separation are all outlined in terms of the aqueous chemistry of germanium. Finally, the production of high purity germanium dioxide and metal is briefly discussed

Jan 1, 1995

By Graham W. Gibbs

The current state of knowledge concerning mesothelioma risk estimates is reviewed. Estimates of the risk of mesothelioma exist for the commercial asbestos fiber types chrysotile, amosite and crocidolite. Data also exist on which to assess risks for winchite (sodic tremolite) and anthophyllite asbestos. Uncertainty in estimates is primarily related to limitations in measurements of exposure. Differences in the dimensions of the various fiber types and of the same fiber types at different stages of processing add a further complication. Nevertheless, in practical terms, crocidolite presents the highest asbestos related mesothelioma risk. The risk associated with sodic tremolite (winchite) appears to be similar. In chrysotile miners and millers, the mesothelioma risk has been linked with exposure to asbestiform tremolite. Exposure to chrysotile in a pure form seems likely to present a very low if any risk of mesothelioma. While the majority of mesothelial tumors result from exposure to the asbestos minerals, there are other well established and suspected etiological agents. While a practical threshold seems to exist for exposure to chrysotile, it is unlikely to exist for the amphibole asbestos minerals, especially for crocidolite. To date there is no indication of an increased risk of mesothelioma resulting from non-commercial fiber exposure in the taconite industry. © 2007 Elsevier Inc. All rights reserved. Keywords: Mesothelioma; Amosite; Grunerite; Taconite; Crocidolite; Tremolite; Anthophyllite; Winchite; Risk estimation; Etiology

Jan 1, 2007

By Koji Matsubara, Yoshiaki Iguchi, Shoji Hayashi

Iron ore particles of a limonite iron ore were reduced completely with H2 at 1023K to 1273K in a fluidized bed. Then, at 973K, the formed iron was exposed to HrH2S mixtures (sulfur activity, as=0.5) for 3.6ks and carbidized with CO-H2-H2S· mixtures at 0.1 MPa. During the carbidization, the particles of about 150mg were sampled at every 600s interval. The sampled particles were analyzed by XRD and chemical analysis for C and S to evaluate the content of Fe3C, Fe5C2, Fe and free carbon. The reaction extent is defined as fo=Xfc3C +xFc5c2; x is the molar fraction of Fe in Fe3C. The carbidization curves can be fitted very well to -ln(l-f0)=g(pb T)t; g(p; T) is the carbidization rate, i.e. the carburization rate on the pore surface of reduced iron. The rate is found to be nearly proportional to the specific surface area of reduced iron, a P 0 , which decreases with increasing the reduction temperature. The value of a P 0 does not change by the carbidization and the stability of the iron carbide product in the atmosphere increases with the temperature.

Jan 1, 2000

By W. R. Hardwick

This paper describing the mining methods of the Inspiration Consolidated Copper Co. is one of a series being prepared by the Bureau of Mines on mining methods and costs in various mining districts of the United States. The story of mining at Inspiration is of particular interest because, after 127,812,000 tons of low-grade copper ore were successfully mined, the mining method was changed from block caving to open-pit. As the open pit became deeper, many features of the former block-caving operation that were exposed elucidated concepts of the mechanics of caving that previously had been assumed but not observed. The conversion to open-pit mining was accomplished by unique combinations of equipment and the introduction of ingenious engineering and operating practices that have extended the expected life of the mine for many years.

Jan 1, 1963

By R. Curtis

To achieve compliance with 2015 EPA Tier 4 Final regulations, which permit only around 10% of Tier 3 particulate matter (PM) and NOx emissions, a number of technologies are being implemented. Use of a fuel borne nanoparticle combustion catalyst reduces the level of PM and unburned hydrocarbons exiting the combustion chamber, alleviating the burden on downstream exhaust after-treatment systems. The impact of an iron-ceria combustion catalyst (GO2) on carbon oxidation kinetics and on diesel engine emissions is presented. The iron-ceria nanoparticles catalyze carbon oxidation at lower temperatures and increase the oxidation rate by a factor of 18 at 400 °C. Engine tests on a generator powered by a John Deere Model engine and field tests on a Cummins ISC 330 tractor truck and CAT 3508B propulsion engines are presented. Use of GO2 resulted in a reduction in PM10 (particulate matter under 10 um) emissions of up to 26% and a hydrocarbon emission reduction of up to 41%. NOx emissions did not increase in these trials and the amount of change depended on engine type. Application of this fuel borne technology for emissions reductions in mining equipment offers significant benefits.

Feb 27, 2013

Jan 1, 1882

By Joner O. Alves

The disposal of scrap tires has been a serious environmental problem. The treatment of this waste by pyrolysis and combustion has advantages since the landfill space is dwindling and the production of fuel becomes of technological interest. However, that processes needs a rigid control of emissions. This work presents a study of the light hydrocarbon gases (HC) generated during the burn of waste tire chips in a two-stage laminar-flow horizontal furnace. Different temperatures in the primary and secondary stage of the furnace were tested, and the oxygen/nitrogen percentage was also varied during the combustion process. A gas chromatograph was used to identify and quantify the components of the gaseous products of combustion and pyrolysis. The results showed the behavior of the gases during the burn of tires, providing valuable information to the control of hydrocarbon emissions.

Jan 1, 2010

By Sparrow G. J

The effect of polyelectrolyte flocculants on the de-watering of a tailing suspension of very fine clay was investigated.Sedimentation and filtration experiments were carried out in the labqratory to characterise the de-watering properties of the tailing. The results were used to calculate the effect of flocculant additions on the drainage and vaporation components of the de-watering of a clay suspension ponded on to a sand drainage bed.A flocculant increased the drainage rate, but decreased the volume of water that could be removed by drainage leaving more water to be lost by evaporation.The sorptivity values measured in the laboratory were used in the de-watering equation previously established for the tailing to estimate the effect of flocculant additions on the time required to de-water the suspension from 18.2 to 60 per cent solids w/w. The calculated de-watering times were found to increase or decrease depending on the volume of water removed by drainage and the prevailing evaporation rate.

Jan 1, 1980

By R L. Langak, R A. Heins

The use of differences in specific gravity between minerals to separate them has long been utilized in the extractive industries. The environmental and cost benefits of the commercialized forms of these processes are well understood and widely used. Gravity concentration is used inter alia in the primary beneficiation of gold, diamonds, coal, tin, ferrous metal ores and andalusite. The potential for economic loss due to poor performance of these gravity processes is significant, but diverse in manifestation and regular process monitoring can prevent or at least reduce these losses. The measurement of performance of gravity processes has always presented a challenge, due primarily to the masses of material involved and the physical nature of the processes, generally typified by long reporting time, and hazardous materials (such as Tetrabromoethane) for float and sink type tests. The development of density tracers has improved this situation, however recovery of these tracers from the process streams created the next set of challenges, requiring significant manpower to physically remove tracers from product dewatering screens. Additions to these tracers (magnetic or x-ray fluorescent) eased the recovery mechanism issues but made them much more expensive to produce, hence operators became concerned about losses during process testing. In addition, magnetic recovery of smaller size tracers by a magnet suspended above a loaded screen panel is still problematic. The development of new low cost magnetic tracers has improved statistical significance of tracer tests, as the tracers themselves can be bought and used in much larger quantities, whilst still remaining economically viable. Coupled with the development of effective magnetic recovery technology, such as the Gekko MagScreen, for even fine sized tracers, on-line, continuous tracer testing is now becoming a reality. Whilst the development of high technology radio frequency detection tracer systems continues, enabling the real time measurement of the process and interpretation of results, miniaturization and recovery of these tracers, which is critical given their costs at present, remains an issue. Keywords: Gravity, process measurement, tracers, magnetic recovery

Jan 1, 2006

I HAVE to thank the members of the Institute most cordially for the honour conferred upon me in selecting me President, which position my poor services have prevented my filling adequately. I have, therefore only been able to stumble through my year of office under the guiding direction of our esteemed Secretary. I fully appreciate the honour done to me; and, now that it is over, I can look back with pride and pleasure at having occupied the chair; but I am told that it remains for me to fill one of the requirements of our Institute and present you with what has been dignified by the name of a presidential address. My relief in complying with this is in the knowledge of its freedom from the usual discussion which appertains to papers presented by our worthy members. It has been usual in the past for the subject chosen to be specially connected with the work immediately engaging the attention of your president, and on this occasion I would like to break away from this time-honoured custom and engage your attention for a brief space on what is equally dear to us all namely, Ideals of the Profession. In doing so, the retort of Whistler to an art student gives me, I must admit, much misgiving, for, on being asked how he developed his artistic talents, replied that he painted what he saw, which produced the immediate reply, "Ah, but the tragedy will come when you see what...

Jan 1, 1909

The Wednesday Morning Session of the Rocky Mountain Coal Mining Institute was called to order by Albert Keenan of the Thompson Creek Coal and Coke Company, Denver, Colorado, in the absence of the President. He introduced Edward Prostel of the University of Wyoming Natural Resources Research Institute, Laramie, Wyoming, who spoke on "Coal Utilization Work at the University of Wyoming." (Please refer to the index for printed text of the paper.) Following Mr. Prostel's talk, R. Park Lamborn of the National Mine Service Company, Pittsburgh, Pennsylvania asked Mr. Prostel two questions: (1) What -has been done in tar research? and (2) Has there been large scale research on brickets? Mr. Prostel stated that he could not say too much about the first question as this research was done in the petroleum department and he would prefer to have a chemist talk about it. As to the second question, the system of carbonization is a big project. There are many possibilities. At the University they are trying to do that in the same unit that produces the char. This system was introduced in Canada. The brickets are bound with sulphite liquor. Mr. Schloss asked Mr. Prostel to report on a project that they have been working on at the University, and Mr. Prostel stated that some time ago they began to experiment to see if it would be economically possible to dry coal at the mine (coal containing 30% moisture) and then ship it a distance of 130 miles to be used. Results are that it would be possible, but will require a considerable quantity. He felt it might be possible to operate such a scheme in a few years.

Jan 1, 1957

By D. Richter

The Pyrometallurgical refining stage of ferronickel manufacturing produces a slag rich in iron and nickel, which is usually further processed for metal recovery. The recovered material is returned to the refining or smelting stages, depending on the amount of impurities. A series of tests was carried out on the Mineração Morro Azul refining slags, aiming at the recovery of the metallic particles through physical processing. Minor changes in the process showed improved results. This paper compares the textures of these slags after being cooled at ambient temperature and granulated under water at high pressure and flow. It concludes that the cooling process is intimately connected to the work index of such slags, thus resulting in direct impact in operating costs.

Jan 1, 2011

By Romano J. Micciche

One of the largest scale uses of a multiple, high-strength steel bar tiedown system is described. Tiedowns were installed to resist hydrostatic uplift forces acting on a section of the Interstate Highway Route I-90 southern approach roadway to the Third Harbor Tunnel, in Boston, Massachusetts. Site specific information is discussed regarding design, testing, and installation of Tiedowns. Conclusions are presented regarding the overall performance of this system and the application of this type of tiedown system on future projects.

Jan 1, 1994

By K. Rainer Massarsch

In some parts of the world, vibrators are used extensively for different types of foundation engineering projects. If used correctly and in suitable soils then vibratory pile driving for example is very efficient. However, soil conditions and the installation procedure have great significance for the driving resistance and affect the bearing capacity of vibrated piles. Also the intensity of ground vibrations which are transmitted to the surrounding soil is affected by the vibration process. In spite of the increasing use of vibrators and the rapid development of vibrator technology, many aspects of pile-soil interaction are not yet understood. In order to asses the importance of factors, which govern pile installation (and extraction), it is necessary to consider the entire chain of vibration energy transmission from the vibration source to the pile, the interaction between the vibrating pile and the soil and the wave propagation in the subsoil, Fig. 1. [ ] Fig. 1. Transfer of vibration energy from the vibrator through the pile into the ground In the present paper, some important aspects of vibratory driving and their significance for pile installation and soil compaction will be discussed.

Jan 1, 1995