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By Gillies A. D S, Lee A. H

The major operational objectives of a mine water resource management system (WRMS) are to supply the water needs of the mine and mill, to minimise disturbance to mining due to rainfall flooding or seepage and to dispose of excess water. Historically, company management have placed a significantly lower emphasis on managing the WRMS as compared to managing production. Changing Government legislation concerned with the disposal of water from mine sites is, in many cases making mining companies look more closely at how they manage their water. For example, within the next few years it is likely that prior to mining approval by the Government, mining operations will have to submit water management plans/budgets and contingency strategies in addition to operational plans. While the formulation of a comprehensive water management plan/budget is an additional cost to the company at the mine establishment stage, such plans can be beneficial to the operation in the longer term.The two keys for the efficient design, operation and development of a WRMS are the establishment of written goals which have managerial priority and secondly, access to appropriate good quality data. Managerial priority towards the WRMS will increase as a consequence of the education of mine operators in the benefits to the operation of good WRMS management or less desirably as a requirement to meet Government legislation. The collection of appropriate WRMS data is a more complex issue and to obtain information efficiently and cost effectively relies on the clear definition of the data application.

Jan 1, 1992

By G. A. Bezuidenhout, S. Bradshaw, W. Malan

"Currently, the matted-based collection process is most widely used for platinum group metal (PGM) recovery. However, because PGM-containing concentrates are becoming more enriched with UG2 (Upper Group 2) low-grade concentrates, this is expected to be integrated or replaced with an alloy collection process.The reduction LG (low-grade) concentrates with silicon carbide (SiC) was investigated. The purpose of the study was to ascertain the feasibility of using SiC as reductant with regard to metal fall, PGM grade in the alloy, slag composition, and overall PGM recovery, and if possible, the integration of such a process in the current matte-based collection process. Rowland and Easterns LG concentrate samples from Lonmin were analysed by Xray diffraction (XRD), X-ray fluorescence (XRF), and inductively coupled plasma mass spectrometry (ICP-MS). It was found that SiO2 and MgO are the most abundant oxides and Pd is the most abundant of the PGMs. Sulphide-bearing minerals such as chalcopyrite were detected in low concentrations (below 1%), and Cr2O3 concentrations are between 2-4%. SiC reduction of Rowland and Easterns concentrate were conducted at 1600°C with reductant to concentrate ratios ranging from 2.5 to 3.5 kg SiC per 100 kg concentrate.The reduction experiments revealed that PGM recoveries from Rowland concentrate were poor. SEM images showed entrained metal prills in the slag phase. The slag viscosity at the end of the melt was calculated by using FactSage, and the results indicated that the viscosity was higher than 4 poise, which is above that of Easterns slag. PGM recoveries for Easterns concentrate were significantly better. More than 85% of the Ir and Pd and almost 60% of the Pt were recovered in a test with a reductant to concentrate ratio of 3.5 kg SiC per 100 kg Easterns concentrate. At this reductant to concentrate ratio, Fe recovery was also the highest, at 66%. SEM imaging of a slag sample revealed few or no metal prills entrained. The FeO content in the initial concentrate charge was then increased by adding Peirce-Smith converter slag in order to decrease the slag viscosity and further increase PGM recovery. A test was conducted with the addition of 10 kg converter slag per 100 kg Easterns concentrate. The reductant to concentrate ratio was kept at 3.5 kg SiC per 100 kg Easterns concentrate. The Ir and Pd recoveries were more than 95%, while Pt recovery was almost 70%. Fe recovery increased to 76%. On the basis of these results an optimum feed ratio between Easterns and Rowland concentrates and Peirce-Smith converter slag were calculated. FactSage predicted that the concentrate charge should consist of 70-80% Easterns concentrate with 20-30 kg converter slag per 100 kg LG concentrate. SiC reduction of this optimum LG concentrate charge is expected to recover more than 90% of all PGMs. Cr and Si concentrations in the alloy will be below 1% in total.The effectiveness of SiC as reductant was also compared to carbon reduction. Carbon reduction of an optimum concentrate charge at the same reductant to concentrate ratio resulted in a marginally higher metal fall than SiC reduction. However, gas emissions and energy requirements are higher for carbon reduction.The study has shown that base metals and PGMs can be recovered in an iron alloy by SiC reduction of LG concentrate with converter slag additions. Integration of such a process into the matte-based collection process could be considered as a future alternative for smelting UG2 LG concentrates."

Jan 1, 2014

By A J. Scogings, W J. Shaw

The successful development of industrial minerals projects requires an integrated, holistic understanding of the metallurgical and product performance test work in the context of the geological setting of the deposit and applied to mining, processing and marketing of saleable products. The product specifications provide the essential starting point for geometallurgical studies. A sound understanding of the desired product is needed to design and interpret a program of test work. Examples are provided from recent studies on bentonite and graphite deposits.For bentonite projects, the naïve testing of only the cation exchange capacity (CEC) as a measure of purity can lead to unexpected outcomes when the deposit is mined. The CEC attribute may remain the same, while other important properties such as pH and swelling index change markedly with depth, due to weathering and oxidation, leading to disappointing production outcomes.For graphite projects it is not enough to report only total graphitic carbon content (TGC). Knowledge is required of the in situ flake size and textures in addition to purity and flake size distribution of extracted graphite, which may all vary from one domain to another across the deposit. Such geometallurgical attributes of the ore will impact on the ‘basket price’ used to estimate the value of marketable parcels of expected product.Disclosure of such information must be considered part of fully informing the market. As with all new project developments, consideration of the JORC (2012) and VALMIN (2015) Codes requires disclosure of all material information. This includes the geometallurgical characterisation, ie those aspects of the mineralogy that impact on resource evaluation, ore reserve definition and project valuation.CITATION:Shaw, W J and Scogings, A J, 2017. The importance of geometallurgical test work for industrial minerals projects, in Proceedings Tenth International Mining Geology Conference 2017, pp 83–92 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

By Albert E. Wiggin, Frederick Laist

Page I. Introduction............................470 II. The Sources and Amount of Slime................470 II. The Composition of the Slime..................471 IV. The Experimental Development of the .Anaconda Slime Plant.. 471 1. The Great Falls Slime Plant and Experimental Work......471 2. The Experimental Work Done at Anaconda..........473 (a) SlimeThickening Devices.............. 474 (b) SlimeConcentrators................. 475 (c) Dewatering the Slime Plant Concentrate......... (d) The Use of Chemicals to Accelerate the Settlement of Slime........................ 478 (e) The Effect of Temperature upon the Settlement of Slime 478 V. A Description of the Anaconda Slime Plant........... 479 1. A Diagrammatic Flow Sheet of Plant............. 480 2. The Slime-Thickening Division................ 480 3. The Concentrating Division.................. 481 4. The Concentrate-Dewatering Division............. 483 5. General Data........................ 484 I. IntRoduction The new slime-concentrating plant at the Washoe Reduction Works, Anaconda, was put into operation during March, 1914. This plant, which has a capacity of 26,000,000 gal. of slime pulp carrying 2,500 tons of solid matter per day, consists of Dorr thickeners and Anaconda multiple-deck slime concentrators. This plant is the culmination of a great deal of experimental work extending over a considerable period of time, which , work will be described briefly in the following pages. II. The Sources and Amount of Slime Up to the beginning of this year, the ore from the Anaconda company's mines in Butte, Mont., has been concentrated both at the Great Falls

Jan 1, 1915

By K. E. Nelson

The effect of thorium and zinc variations on the strength and 100-hr creep characteristics of Mg-Th-Zn-Zr alloys was investigated. Optimum resistance to creep at 650° and 700°F are attainable within a certain range of thorium and zinc contents. This range does not conform to that which develops maximum tensile properties. RAPID advances have been made during the last few years in the development of magnesium alloys for elevated temperature applications demanding high resistance to creep. The beneficial effect of rare-earth metals on the creep resistance of magnesium alloys has been emphasized by a number of publications1-13 and such alloys are now in commercial production. The use of thorium as an alloying ingredient in magnesium was mentioned by McDonald and also in two Alien Property Custodian patent applications.10,17 The initial observation of Sauerwald that thorium contributes still higher creep resistance to magnesium than is attainable with rare-earth metals has recently been substantiated.'" " In fact, it has been demonstrated that the useful temperature range of magnesium alloys is appreciably extended by the use of thorium. In all cases, it was observed that zirconium must be included in the alloys in order to render them fine grained and more readily castable. Several recent publications:2-27 indicate that a still further improvement in creep resistance and a further extension of the useful temperature range can be realized by the addition of zinc to alloys. The primary purpose of this paper is to present the results of a comprehensive study of the effect of zinc on the strength and creep characteristics of Mg-Th-Zr alloys. Compositions covering the range of thorium content from M to 6 pct and zinc content from 0 to 5 pct have been investigated. The creep characteristics at 650" and 700°F reported in this paper are based on results of tests of 100-hr duration. It is appreciated that creep tests of 100-hr duration might not yield adequate data for design purposes for parts with much longer expected life. However, for the purposes of the present discussion, it is felt that the combination of stresses and temperatures used in the 100-hr creep tests have yielded a clear representation of the compositional variation of creep resistance at the temperatures investigated. Creep tests of 1000-hr duration are now in progress on a few of the most promising alloys. Preparation and Testing of Alloys The alloys studied in this intensive investigation were prepared in 25 lb capacity mild steel crucibles. The thorium, zinc, and zirconium were alloyed and poured as described in earlier publications The thorium was introduced into the melt in the form of a Mg-Th hardener," the zinc added in the metallic form, and the zirconium alloyed in the form of the commercial hardener containing magnesium and 30 to 50 pct Zr.10, 26 Fluxing practices for melting and refining were the same as for magnesium-rare-earth metal-zirconium alloys. The melts were sampled for analytical determinations and poured into separately cast 1/2 in. diameter standard tensile bars. The test bars were given a precipitation treatment of 16 hr at 600°F in laboratory furnaces. It has been shown by other tests that a high temperature solution treatment followed by an aging treatment is unnecessary for the development of optimum properties in Mg-Th-Zn-Zr alloys. The selection of 600°F as the aging temperature was based on an attempt to achieve metallurgical stability without coalescence of the undissolved phases and the attendant loss in strength. The thorium, zinc, and zirconium contents of each melt were determined chemically. The zirconium contents are reported in two parts, "soluble" and "insoluble," referring, respectively, to the portions present in the alloy which are soluble and insoluble in dilute HCl acid. Distinction is being made between these two components of the zirconium content in the alloys because it has been found that only that portion of the zirconium content which is soluble in dilute inorganic acids affects the structure and properties of the alloys. The usual impurities consisting of copper, iron, manganese, and nickel were determined spectroscopically. The analysis for each melt is listed in Table I. A description of the methods of tension and creep testing has been detailed in earlier papers. The tests were performed with the cast skin re-

Jan 1, 1954

By T. Grammatikopoulos, C. Gibson, M. Aghamirian

"Lithium is a soft, silver-white alkali metal with atomic number 3. As of 2015, the end use of lithium was estimated to be as follows: lithium-ion batteries (35 percent), ceramics and glass (32 percent), lubricating greases (9 percent), air treatment (5 percent), continuous casting mould flux powders (5 percent), polymer production (4 percent), primary aluminum production (1 percent) and other uses (9 percent) (Jaskula, 2014). Lithium is found in brine lake deposits containing lithium chloride and in hard rock pegmatite deposits. It can be sold in a range of product types; as mineral concentrate, brine, compound (lithium carbonate or lithium hydroxide) and metal depending on its intended end use (Goonan, 2012; Jaskula 2014).In the 1990s, the United States and Chile were the largest producers of lithium globally, primarily from brine operations (Ober, 1994). Most of the lithium compounds produced during this period were consumed in the glass, ceramics and aluminum industries. In the 1980s and 1990s, there were two major lithium operations in the United States: brine operations at Silver Peak, NV and a spodumene mine and lithium carbonate/lithium hydroxide plant in Kings Mountain, NC. The Kings Mountain operations ceased production in 1991 and were eventually dismantled in 1994. Brine operations were also active in Argentina and Chile, while the largest lithium ore deposit in the world was operated at Greenbushes, Western Australia. During this period, it was predicted that major shifts in demand for lithium would come from the success and widespread use of electric vehicles (Ober, 1994).Lithium is still produced from the brine operations at Silver Peak. But in more recent years, Chile has become the world’s leading producer of lithium carbonate from brines. Australia has maintained its position as the world’s largest producer of lithium mineral concentrate, the majority of which is exported to China to produce lithium carbonate and lithium hydroxide (Jaskula, 2014).A spodumene concentrate was also produced at the Tanco Mine in Manitoba, Canada beginning in the 1980s through to 2010 when lithium operations were suspended due to fluctuations in the lithium market price (Martins et al., 2013)."

Jan 7, 2017

By David Clarry

?The issue ?reduction requirement ?Planning abatement steps ?Energy Management & Energy Efficiency ?Energy Recovery / Utilization ?Alternative Energy Professional Services Overview ?Capital Projects and Construction ?Project Development and Planning ?Engineering ?Project management ?Construction management ?Consulting ?Process ?Business ?Environmental ?Technology ?Operational Services ?In-house engineering services for operations

May 1, 2009

Such are the rigors of climate and topography of western Tasmania, that much of the area has remained uninhabited. The mountains, rising to peaks above 5000 ft high, receive the winds out of the west and precipitate 110 in. of rainfall a year on this coast. The drenched forests have a primordial look with such unfamiliar trees as the tru-sassafras, blackwood, cheesewood, ti tree, and man tree ferns. Prospectors speak of the "horizontals," trees which, in the dense foliage, grow out flat. When the explorer climbs over them he does not come back to the ground but continues forward on dense vegetation with the ground many feet below. Gold was discovered by the intrepid prospectors of the late nineteenth century and stamp mills were erected in the vicinity of Zeehan and Queenstown. At Mount Lyell, mining began for gold in the ironstone capping. The familiar story, of course, is that copper was found beneath the gossan and it was this mineralization that lead to permanent mining operations. Two companies began mining at Mount Lyell and their history from 1893 to 1902 was marked by an unreasonable competitiveness, human perversity and technical difficulties. The North Lyell and Mount Lyell companies were mining copper ores within one mile of each other separated only by a ridge. Each company built its own railroad and harbor. For six years of struggle both companies tried to work out the metallurgical problem which was the key to profit. Although they didn't know it, the two ores were complimentary and could have been smelted together. North Lyell ore was strong in silica and weak in iron, whereas Mount Lyell was fortunate in having a first-class metallurgist in Robert Sticht, from Brooklyn, N. Y., who in 1902 successfully achieved pyritic smelting without the use of carbon fuel.

Jan 10, 1964

By A. Lee Barrett

THE Maintenance Committee of the Coal Division of the American Institute of Mining and Metallurgical Engineers is presenting as a part of this report the second of a series of maintenance cost comparisons. The committee's purpose is to assemble maintenance costs on all equipment connected with mechanical operations at the face of coal mining and to arrange these costs by districts so that comparisons can be made between districts and within districts. The committee, this year, sent 35 questionnaires to representative coal companies who either reported last year or had advised specifically of the inability to report to last year's questionnaire primarily because of limited time. The response to the questionnaire this year was not as good as last year, only 20 of the 35 selected companies returning a completed questionnaire. This year's data has been .compiled and combined with last year's data to present a comparison of the 1945 and 1946 costs of loading machines, shortwall cutting machines, universal cutting machines, service locomotives, shuttle cars, and mine cars. The same tabulation by districts is used as was used for 1945. As was indicated by last year's report there is considerable variation in the maintenance cost of mining machinery in the various coal mining districts and due to this high variability it was not felt practical to attempt to Arrive at weighted averages. Consequently, all average figures used in this report are straight averages. An analysis was made of companies reporting both this year and last year in an attempt to determine the trend in maintenance costs for different classes of equipment. Ten representative companies are used in this computation. Table I shows the average cost for 1945 and 1946. It is felt that the negative trend in the maintenance cost of universal cutting machines probably represents the effect of the purchase of a relatively large number o new machines in 1946 with little maintenance cost appearing during the first yeas of operation. The grand total figure indicates an upward trend amounting to plus 18.7 pct. However, this figure is viewer with some suspicion because of the effect of the universal cutters decreasing maintenance cost and it is concluded that direct application of percentage increase should be made to types of equipment. In Table 2 covering maintenance costs of various types of mining equipment for 1945 and 1946 the results, obtained in Table I indicating trends were applied to those

Jan 1, 1948

By R Turner, P Hatherly, T Medhurst

Borehole geophysical logging data are routinely acquired during exploration of coal deposits in Australia. These data are commonly used qualitatively to identify and correlate coal seams and geotechnically significant interburden rock units. Some quantitative analysis, such as using sonic logs for rock strength estimation is becoming increasingly widespread. This paper discusses results from a project aimed at expanding the quantitative approach to more detailed mineralogical and lithological analysis, which leads to improved geotechnical characterisation for mine planning and mining hazard reduction. A standard suite of wireline logs measuring density, natural gamma, sonic and neutron were analysed from three coal mines in the Bowen Basin. Thirty-nine samples from cored sections of the boreholes were analysed by X-ray diffraction, spectral gamma counts and hyperspectral scanning. Using a standard petrophysical approach to calculating porosity, shale and matrix components from a combination of density, natural gamma and neutron logs, a good correlation with observed mineralogy was demonstrated. However, unusual mineralogies such as heavy minerals or low-potassium clays may distort this analysis. Simultaneous evaluation of all available geophysical logs by modern data mining methods was able to show how these ambiguities may be solved.

Jan 1, 2006

THE Geophysics Education Committee has devoted several years to a consideration of the problem of training geophysicists. Past reports have dealt largely with fact finding and with the discussion of particular aspects of geophysical education. In the present report it is proposed to review the subject more comprehensively. This involves the question of what educational qualifications the geophysicist of the highest professional standards should possess, and the related question of what changes must be effected in existing educational institutions in order that prospective professional geophysicists may obtain instruction of the desired quality. The type of geophysicist here contemplated is one familiar with what is known already in the several branches of earth physics, and capable not only of following contemporary progress in any of these branches, but of contributing to that progress in a research capacity. Geophysics in its broadest sense, as has been emphasized repeatedly by this Committee, is the study of the physics of the earth and of terrestrial processes. This includes both the static and the dynamic characteristics of the gaseous, the liquid, and the solid portions of the earth, as well as its gravitational, thermal, and magnetic and electrical manifestations. Some branches of earth physics have been cultivated but slightly; others have reached an advanced state of development. Those branches whose development is sufficient to warrant explicit recognition in the form of organized Sections of the American Geophysical Union are: geodesy, seismology, tectonophysics, and volcanology, dealing with the rock constituents of the earth; oceanography and hydrology with the aqueous constituents; meteorology with the atmospheric constituents; and terrestrial electricity and magnetism with the electromagnetic manifestations. At present, instruction on the professional level in any of these branches of earth physics can be obtained in but few universities in North America. In most institutions where such instruction is undertaken different subjects are given in different and independent departments. Geodesy and hydrology are taught, if at all, as a part of civil engineering. The nearest approach to volcanology and tectonophysics ordinarily is represented by petrology and structural geology given

Jan 1, 1944

By John J. Gordon, Neil K. Cooperrider

The International Organization for Standardization (ISO) standard ISO 2631 [1,2] provides three methods for evaluation of human exposure to vibrations that contain occasional shocks or impacts. Part 1 of the standard specifies the running r.m.s. or maximum transient vibration method (MTVV) and the fourth power vibration dose value (VDV). Part 5 of the standard provides a method of computing the stress in the lumbar spine for humans exposed to multiple shocks. Alem et al [3] have reported application of these methods to data for tactical ground vehicles. This paper reports and compares VDV and spinal stress evaluations of more than 90 hours of vibration and shock measurements on North American locomotives engaged in through freight operations. The measurements evaluated in this paper were obtained for full crew shifts on 19 freight locomotive runs on mainline track in locations from New York to California. The shifts ranged in duration from 187 minutes to 497 minutes. The average speeds for the shifts were from 21.0 mph to 54.6 mph. All measurements were made on locomotives hauling freight trains in regular revenue service. Data Acquisition and Processing The results reported here were computed using test data acquired from a tri-axial seat pad, accelerometer at a sample rate of 400Hz with an anti-aliasing filter corner frequency of 100Hz. The VDVs and the lateral and longitudinal spinal stress values were computed directly from the acquired test data according to the procedures specified and described in [1] and [2]. The vertical spinal stress values were computed by converting the as-acquired test data to a sample rate of 160Hz for input to the vertical spine model, as required in [2]. The conversion of the test data from the as-acquired sample rate of 400Hz to the required sample rate of 160Hz involved up sampling or interpolating the test data to an equivalent sample rate of 800Hz, band limiting the resultant data with a low-pass filter corner frequency of 60Hz and finally down sampling or decimating the 800Hz data to a sample frequency of 160Hz. Discussion The vertical VDVs computed according to [2] for the 19 shifts ranged from 2.68 to 9.33 m/s1.75. In all but one case, the vertical values were greater than the values for the lateral or longitudinal directions. Note that the health guidance in [1] puts the lower boundary of the health guidance caution zone at a VDV value of 8.5 and the upper boundary at 17 m/s1.75. The daily equivalent static compression dose computed following [2] ranged from 0.123 to 0.434 MPa. Health guidance provided in [2] states that there is a low probability of an adverse health effect if the daily dose is less than 0.5 MPa.

Jan 6, 2006

By José Luis Limaymanta Marcos

En la última Cumbre de Países de América Latina, Unión Europea y el Caribe, realizada en Lima, se evidenció la necesidad de realizar cambios en los países para disminuir la brecha de la desigualdad y se elimine la pobreza -en tanto educación de calidad y excelencia. Para el caso peruano, dicha pobreza radica en las zonas de influencia minera, donde nacen los conflictos sociales. En ese sentido, el presente trabajo describe un modelo de desarrollo solidario que pueda reducir este impacto social a través de una educación de calidad, el cual se sustenta sobre la base de las transferencias de los beneficios que genera la minería tales como: canon, regalías, así como reforzar el crecimiento de los beneficios indirectos tales como los puestos de trabajo colaterales del rubro minero para integrantes de las zonas de influencia minera, el uso, consumo de insumos y servicios de PYMES establecidas en estas áreas y cuyos productos se orientan a las Empresas Mineras.

Sep 14, 2009

By Daryl L. Gusey, John T. Neubert, Matthew A. Sares

The Colorado Geological Survey completed an inventory of environmental degradation associated with abandoned and inactive mines on National Forest System lands in Colorado. In the course of the inventory, areas with naturally occurring acid rock drainage were also noted. Approximately 18,000 abandoned mine- related features were inventoried, including about 900 features that are considered significant enough environmental problems to warrant further investigation. Water quality data, such as pH and conductivity were gathered at all features where water was present, such as draining adits, seepage at the toe of dumps and tailings, and standing water in shafts. Samples were taken where field tests indicated low pH andlor high conductivity, including several areas with naturally occurring acid rock drainage. Samples were analyzed for dissolved and total metals, and for selected anions. All mine locations and data collected by the field geologists were entered on field forms and, subsequently, into a computer database and GIS format. With the information provided by the inventory, the Forest Service, in cooperation with other agencies, has been able to prioritize abandoned mines for reclamation. In most cases, cleanup is approached on a watershed basis. Mines in priority watersheds have been selected for reclamation first. Watersheds where studies prerequisite to cleanup are occurring include the upper Anirnas River, Willow Creek (tributary to the upper Rio Grande), Chalk Creek (tributary to the upper Arkansas River), the Uncompahgre River, and the Alamosa River. During the inventory, evidence of naturally occurring water quality degradation was found in areas where little or no evidence of mining activity exists. These areas include the upper Alamosa River, the Middle Fork of Mineral Creek, Peekaboo Gulch, and Handcart Gulch. Water from these natural sources has been found to significantly exceed Colorado water quality standards for several metals.

Jan 1, 2000

By K Dagdelen

A vehicle proximity warning system is being developed using GPS and wireless local area networks to improve safety of off-highway trucks in open pit mines. After two an a half years of research, software development, and laboratory testing, field tests were carried out at operating limestone quarries and open pit mining operations to evaluate GPS accuracy and overall system effectiveness under rugged operating conditions. This article describes the progress made on this NIOSH funded project and discusses the GPS accuracy tests and overall system tests that were carried out during 2001 at the Morenci open pit copper mine in Arizona.

Jan 1, 2003

By B. W. Madsen

Experimental results obtained from large scale (7 tons), long-term (500 days) leaching of low tenor copper sulfide ores were interpreted by a geometric model involving the movement of a reaction zone through the ore fragments. The postulated leaching mechanism involved mixed kinetics and included diffusion of the reacting species through the host rock and a chemical reaction at the surface of the mineral particles. Ore properties which were considered were ore particle size and shape, grade of ore, and mineral content. Excellent agreement between the mixed kinetic model and the laboratory leaching results was obtained when minus ½ inch ore particles were not included in the leach. Also, a satisfactory prediction of copper recovery from plus ½ inch ore with a different particle size distribution was made; however, it was necessary to modify the shape factor in the model. Predictions of copper recovery from an ore sample which included the minus ½ -inch fine fraction and leaching for 460 days was 56.5 percent, and the recovery from leaching was 47.0 percent. The presence of fines caused channeling and uneven solution distribution and inhibited the leaching rate.

Jan 1, 1974

By Frank C. Smith

The following article covers the history of a metallurgical campaign, commenced in March, 1905, at the mines of the Socorro Bold Co., in the so-called desert region of Yuma county, Arizona. The results obtained were simply a function of necessity, as will be seen from the description of the local economic conditions and the character of the ores treated. The mines and mill of the Socorro Gold Co. are located near the small village of Harrisburg, about 60 miles from Congress Junction, Ariz., which, at the time this work was undertaken, was the nearest railroad station, and from which all supplies were brought by wagon through the desert, at a cost varying from $10 to $15 per ton in addition to the railroad freights. Wood, the only available fuel, cost $7 per cord. Water for all purposes was pumped to the plant from a well in the valley about 4 miles away. Under the Arizona law, a working-shift is 8 hr. Wages were $6 per day for foremen and mill-men, $4 per day for blacksmiths and engineers, $3.50 per day for miners, and $3 per day for shovelers and trammers. The ore consisted of quartz, in which, above the 250-ft. level, the iron-minerale were largely oxidized and some free gold was visible; below that level few traces of oxidation occurred, and pyrite constituted the principal mineralizer in the quartz, together with occasional pockets of galena and a few eccentric specks of covellite. The 20-stamp mill was equipped with plates for amalgamation, and three Standard tables for concentration. The tails from the tables mere elevated by a centrifugal pump to a launder, by which they were conveyed to a 60-ton cyanide-mill for further treatment. The cyanide-mill was erected at so great a distance from the stamp-mill that a separate crew of workers and a separate power-plant were necessary. No arrangement had been made for the treatment of the concen-

Jan 1, 1907

By Tang Chaobo

Employing manganese carbonate ore and zinc oxide dust as material, Mn-Zn compound oxide powder for soft magnetic ferrite was prepared by a serial methods, as follows: leaching by using sulfuric acid, removing aluminium and silicon by neutralization and flocculation method, using ammonium bicarbonate to co-precipitating Mn and Zn, calcinations and washing to removing impurity content. The optimal technical condition was obtained by experiments. The difficulty of removing impurity such as Si, Al, Ca, Mg, from leaching solution was solved. The impurity content in the production meets with the preparation standard of high quality soft magnetic ferrite. The compound oxide powder obtained in the experiment was made into lower power loss magnetic ferrite, the quality of magnetic ferrite meet the standard of PC40 which was established by TDK corporation.

Jan 1, 2006

By C. H. Fisher, M. L. Fein, A. Eisner, G. C. Sprunk, Loyal Clarke, H. H. Storch

"The large reserves of low-rank coals in the western United States are at a disadvantage in competing with the more mature but less plentiful eastern coals, which are nearer important markets and are more suitable for combustion and coke production. However, low-rank coals generally are amenable to hydrogenation, and the western coals might become an important source of liquid fuels and organic chemicals when petroleum is less plentiful.In view of these facts an the tremendous quantities available, further information on the western coals clearly desirable. The purpose of the work described in this paper was to study the hydrogenation characteristics of some of the low-rank western coals in discontinuous converters. The data obtained in this manner, which are inadequate for predicting the suitability of coals for large-scale continuous hydrogenation, were used as a basis for selecting samples for further study in the Bureau's experimental coal-hydrogenation plant (26, 35). 8/ Because of the general importance of the western coals and recently demonstrated relation between coal hydrogenation and petrograghy (14, 15, 16), the proportions of anthraxylon, (vitrain), translucent attritus, and opaque matter were determined. In some instances samples of anthraxylon were isolated and hydrogenated separately so that their properties might be compared with those of the entire coal. The samples studied include peat, brown coal, lignite, sub-bituminous coals, and low-rank bituminous coals."

Mar 1, 1940

By Joel Darmstadter

The position of the coal industry in America’s fuel and power picture remains one of prime importance. Measured in Btu terms, the industry is the country’s leading energy producer and an important exporter. Foreign coal sales yield annual proceeds of about $4 billion. Coal’s one-fifth share of the nation’s energy consumption is nearly as high as that of natural gas. Coal is the electric utility sector’s principal fuel supplier. It accounts for about55% of the electricity generated at power stations.

Jan 1, 1999