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By E. Marè, D. R. Groot, R. Engelbrecht, T. Coetsee

Hydrogen peroxide is often used as an oxidising agent in experimental waste electronic equipment (WEE) leaching work. However, the high cost of peroxide is a negative factor in its consideration in further process development. A few studies have reported on the efficient application of peroxide addition schedules to ensure optimum reagent consumption. Large quantities of unleached substrate material contained in WEE feed material result in a large dead volume of material in the leaching reactor. This factor necessitates fast reaction rates to enable the use of a high feed material throughput reactor to enhance overall project viability via hydrometallurgical processing. In this study the effects of hydrogen peroxide addition schedules on base metal leaching efficiency and solution temperatures were tested at laboratory scale. The results showed that overall peroxide consumption can be optimised to lower levels by matching peroxide additions to the particular feed material’s leaching behaviour. A simplified integrated model for peroxide decomposition is used to explain its effect on solution temperatures and leaching rates. Keywords: Peroxide consumption, waste electronic equipment, copper leaching, integrated model

Jan 1, 2020

By Lyman C. Hitchcock

The objective of this program was to determine the minimum luminance requirements for underground coal mining work from the working face to the first transfer point. The resulting data encompasses 114 visual tasks from conventional continuous and longwall mining methods representing the salient visual tasks found in the jobs listed. Cutter Operator Roof Bolter Face Drill Operator Airdox Operator Longwall Jackman Shuttle Car Operator Loader Operator Shot Fireman Continuous Miner Operator Longwall Head Conveyor Operator Longwall Tail Conveyor Operator

Jan 1, 1973

By Victor E. Kral

"SUMMARYA preliminary examination of the Buena Vista iron deposit was made in June 1942 by Paul E. Pesonen, mining engineer of the Bureau of Mines. Subsequent examinations were made by D. W. Butner, of the Bureau, in March 1943, and by the author in July 1944, who recommended exploration by diamond drilling, trenching, and sampling. Work on the project was done during the period March 28 to May 26, 1945.Property holdings, comprising 16 claims known as the Buena Vista group, are situated in sec. 4, T. 24 N., R. 34 E., Mount Diablo base and meridian, north Churchill County, about 37 miles east of Lovelock, Nev.Three diamond-drill holes totaling 575 feet were drilled; 45 small pits and ten trenches, totaling 435 linear feet, were excavated, and 84 channel samples totaling 862 feet were obtained under supervision of the Bureau.Purpose of the project was to determine the possible downward extension of the mineralized sections exposed in the outcrops and to determine grade of the ore.Bureau work was confined to one claim only - the Iron Mountain."

Jun 1, 1947

By R. E. Wagner

MISSOURI's famous lead area, in what is known as Southeast Missouri, is locally termed the "Lead Belt." These deposits are in the Bonne Terre dolomite of late Cambrian age which has a thickness of nearly 400 ft. Underlying this is the La Motte sandstone which varies in thickness from 0 to 400 ft. The La Motte beds are deposited directly on the ancient erosion surface of Pre-Cambrian porphyries and granites of probably Algonkian age. The buried igneous peaks extend up into the Bonne Terre in several areas within the Lead Belt. Overlying the Bonne Terre are shales and siliceous dolomites of late Cambrian and early Ordovician age. Within the Lead Belt these have a thickness of from 0 to 500 ft. The district is bounded in general on the southwest by the Sims Mountain fault, on the northwest and north by the Big River fault, and on the

Jan 1, 1947

By G. J. Hartman

The Fort Cady in situ borate mining project involves recovery of boron from a mineral deposit located over 1400 feet below the surface. The resource recovery method is being developed using in situ mining technology employing weak acid solution injected directly into the ore body. As the acid contacts the calcium based ore (primarily natural colemanite), the contained borate values are digested as boric acid. This boric acid solution is then pumped to the surface by use of submersible pumps. At the surface the borate values are recovered as a finely divided solid white powder after a series of chemical reactions and precipitations resulting in the production of calcium borate. The refined product is then sold under the trade name CADYCAL 100.TM All environmental permits for up to a production rate of 90,000 tons per year have now been obtained. These permits required an Environmental Impact Study (EIS) for federal lands and an Environmental Impact Report (EIR) for the private portion of the property. Regulatory permitting took over 5 years to obtain all authorizations for this operation. The ore body has an average thickness of 118 feet extending over 273 acres. At a production rate of 90,000 tons per year with only a 70 percent resource recovery allowance, in place reserves are sufficient to sustain production for over one hundred years.

Jan 1, 1997

By Singh BN, Chakravarty PK, Chatterjee LM

Indian blast furnaces operate with coke gener- ally containing 24 to 28% ash compared to 10-15% ash in coke in most other parts of the world. The operating problems are further aggravated by the high alumina content and the adverse alumina to silica ratio in the ore. The above factors not only increase the coke rate but, at the same time, increase the flush slag volume, make the bosh slag highly limey and thereby viscous, and produce a flush slag containing 24 to 26% alumina. Relative- ly low flame temperatures (RAFT) make conditions more difficult. The high basicity of the bosh slag limits the maximum flush slag basicity to around 1.0, beyond which the burden movement is adversely affected by the viscosity of the bosh slag: This effect is partly controlled by operating blast furnaces with high MgO in the flush slag (around.10%), which also improves the desulphurizing power of slag. Steps are underway in some plants to inject lime through theòtuyeres to control the bosh slag basicity and also to neutralise the large quantity of silica which is released at the tuyere level from the coke ash, so that the silicon content of the hot metal can also be controlled. High bosh slag basicity coupled with the characteristics of iron ore/aggolmerates, widens the softening-melting zone and alters the shape of the softening-melting zone. This leads to operat- ing difficulties and poor hot metal quality. This paper discusses the above aspects of Indian blast furnace operation and steps being taken to surmount some of the above difficulties.

Jan 1, 1981

By M S. Kizil, T OÆConnor

It is predicted that underground coal mines in the Bowen Basin will have a significant rise in heat problems as mines aim to increase production, depth of extraction and length of longwall panels. At an actual Bowen Basin mine, extended longwall panels greater than 4 km in length are planned to be mined at depths with a virgin rock temperature (VRT) of more than 40¦C. Research has been completed into the reasons for the substantial increase in temperature at the face for underground coal mines in the Bowen Basin. An analysis into heat loads produced at the Bowen Basin mine for the development and production phases shows a significant amount of additional cooling will be required to ensure safe working temperatures. All of the major sources of heat, which included both natural and mine induced heating, were considered for the analysis. Maximum heat loads were assessed, together with peak intake surface temperature to determine the maximum cooling capacity required at a Bowen Basin mine. These maximum heat loads were assessed for a specific longwall panel, Longwall A, which extends to over 4.1 km in length and at a maximum depth of over 330 m, resulting in a VRT above 40¦C. The cooling system positional efficiency was analysed, determining that underground cooling via an indirect heat exchanger was preferred to increasing the capacity of the current bulk air cooling (BAC) on the surface. A preliminary cost analysis was also detailed which compared the cost of additional BAC compared to implementing underground cooling.CITATION:OÆConnor, T, Kizil, M S and Belle, B, 2013. Required cooling system capacities for extended longwall panels at a Bowen Basin mine, in Proceedings The Australian Mine Ventilation Conference , pp 249-256 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013

By S. Dawson

The Republic of South Africa has become a major producer of opencast coal in recent years. Opencast production commenced in 1970 and by 1977 some 10 million run of mine tonnes were being produced annually, Since then surface mine activity has increased to more than 60 million tonnes which represents approximately one third of the total annual South African? coal production. Whilst a substantial portion of this production is exported, the majority is used in the domestic market, The largest consumer, being the South?\ African Electricity Commission (Eskom), produces most of South Africa's electricity using coal fired power stations,

Jan 1, 1990

By G. Shaw

IN recent years, most of the reconnaissance work of the Geological Survey of Canada has been mapped on a scale of 1 inch to 4 miles. Topographic base maps, commonly made from aerial photographs, were available to the geologist for such work. The advent of war curtailed aerial photography for civilian purposes, and by 1941 all areas already photographed had been geologically mapped. Nevertheless, the need for geological maps to assist post-war prospecting was so apparent, and the country to be covered is so vast, that some new method of rapid mapping had to be devised. It was felt that the need would be met if geological maps could be produced at a scale of 1 inch to 8 miles, provided they were sufficiently accurate in topographic detail to serve as guides to travel. Though in such maps there would be considerable sacrifice of geological detail, they would serve to outline, at least approximately, the major geological units, some of which might prove of sufficient interest to warrant later detailed study. It seemed that such mapping would be particularly useful in the northern regions of Canada which the work of early explorers has indicated are underlain largely by granitic rocks. These, so far as is known, are barren of mineral deposits, but within them are known to be areas or bands of 'greenstones' of the type that, in some localities, have been found to contain valuable orebodies. The problem, then, was to devise a method of mapping, particularly of such greenstone bands, that would make it possible to cover a relatively large area-say 30,000 square miles-in one season and at a cost below that of 4-mile mapping, with, of course, some sacrifice of accuracy. The problem seemed to be threefold: (a) to observe as much of the bed-rock as possible; (b) to produce a topographical map of as much of the area as possible, with particular reference to portions of geological interest; and (c) to cover as large an area as possible in a limited time, which meant faster modes of travel than have hitherto been used. The obvious answer to all three phases of the problem was the use of aircraft. If rock types could be broadly differentiated from the air, reconnaissance traverses by air would supply the answer to the first part of the problem. For topography, air photographs taken on reconnaissance flights appeared to be the answer. For the third phase of the problem, the use of aircraft was ideal.

Jan 1, 1943

Coal-derived flue gases contain CO2/SO2 and these contaminants preferably have to be captured by cheap sorbents. This remediation approach is from the standpoint of addressing issues such as global warming, acid rain and development of Advanced Power Generation Systems and to realize the economic gain as well. Conventional and existing dry scrubbing technologies use regenerable sorbents which are pollutant specific and require expensive stabilizers in order to attain versatility. This paper discusses the use a novel class of sorbents prepared from the heavy metal contaminated Berkeley Pit water (Butte, Montana) by a proprietary process developed at The University of Nevada, Reno. These sorbents are activated mixed spinel ferrite (MxFe,_X04)' Preliminary experimental results show that the sorbents have good desulfurization and CO2 decomposition capacities. The decomposition effectiveness of these mixed spinel ferrites was studied at 300°C and compared against the synthetic magnetite obtained from ferrous sulfate solution in our laboratory. The results indicated that the mixed spinel ferrite had good affinity for the adsorption and decomposition. The CO2 decomposition data of both sorbents fitted the first order reaction kinetics. Even though the surface area of the magnetite was higher than that of mixed spinel ferrite, the CO2 decomposition rate of the mixed spinel ferrite was estimated to be 2.5 times higher than that of magnetite under identical conditions. The carbon analysis deposited on the sample indicated that the CO2 was 100% decomposed into carbon and other carbon! hydrogen compounds by the mixed spinel ferrite whereas the conversion was 43% by the magnetite. In terms of specific adsorption of carbon, ferrite was 3-5 times more efficient than magnetite.

Jan 1, 1996

By N. Ahmed

"This paper is concerned with the drainage behaviour of gangue mineral in the froth phase. Experiments were carried out in a continuous laboratory flotation cell in which froth depth and bubble size can be changed independently. The fraction of solids returning from the froth to the pulp zone was expressed using a rate constant by considering the appropriate froth regimes. A mixture of hydrophilic solids (silica) and floatable particles (glass ballotini) was used as a flotation feed. Samples of glass ballotini of different hydrophobicities were obtained, using controlled silanation. Three samples, with contact angles of 50, 66, 82 degrees, were used. The effect of the initial bubble size (pulp bubble size), concentration of gangue mineral in the froth zone, and froth depth on the drainage of silica, were also investigated.Typical results obtained from this study is shown in the figure given below. In this figure drainage rate constant for the entrained solids in the presence of particles of the three hydrophobicities is plotted against froth height. As observed, the drainage rate of the entrained solids increases considerably with an increase in the degree of hydrophobicity. Concerning the effect of pulp bubble size on the drainage rate of entrained solids, larger bubbles always give higher drainage rates due to formation of relatively loose froth structures which allows gangue particles to easily move down to the pulp zone. Conversely, smaller bubbles exhibit lower drainage rate constants, in particular at shallow froth depths."

Jan 1, 2003

By CHARLES R. KETES

I. INTRODUCTORY. INDUSTRIALLY, the most important service that geological science can now render to mining in the Upper Mississippi leadand zinc-fields is to devise some practical scheme whereby the productive ore-belts may be located with greater certainty than they have been in the past. Up to the present time there has been little service of this kind, and in spite of all that has been worked out concerning the geologic features of the region, and notwithstanding all that has been written about these ore-deposits, this particular phase of the subject has been, for some reason or other, the very one that has received the least consideration. The neglect by geologists in this respect has been all but complete. The following notes are suggestive of some practical solutions to the problems presented. As here suggested, the geologic relationships of the ore-bodies were surmised some years ago, though somewhat vaguely perhaps. No opportunity for securing critical data appeared until recent investigations of a private character were undertaken, which bad in view the extensive prospecting of undeveloped areas. Fresh from rather wide experiences of a decade in the principal mining-regions of four continents, and after a lenstrum's residence among the chief mining-camps of the West and of Mexico, under conditions which measured geologic hypotheses in meters and rigidly tested their values in, terms of dollars, the recent return to the Joplin field and a new survey of its ore-conditions were fraught with somewhat unexpected results. Aspects of the ore-deposition were presented of which previously there was no hint. Ten years' absence from the district had tended greatly to clarify former hazy impressions. It enabled many features, then only dimly outlined, to be considered more nearly in their true perspective and in their real relationships to their surroundings. It permitted a great mass of details collected a dozen years before in connection with the work of the Missouri Geological Survey to be viewed under new light and to

Feb 1, 1909

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 R. D. Sharpe

Gypsum wallboard manufacturers in the United States shipped 3.18 billion m2 (34.2 billion sq ft) of wall-board products during 2004 versus 2.93 billion m2 (31.5billion sq ft) in 2003. Following a historic high production of gypsum wallboard products in 1999, production decreased in 2000. But it has steadily increased during2001 through 2004. Wallboard production in the United States increased about 8.6 percent in 2004 from 2003. Following several years of a “building boom” of new wallboard plants and the expansion of the manufacturing capacity of several existing plants, 2004 was a relatively quiet year. However, several new plants and capacity expansions were announced or are in progress during 2004.

Jan 1, 2005

By W. E. D. Stokes

The faster that aircraft fly the sooner some new and stronger material must be found to take the place of the present aluminum alloy used in all-metal planes. Experts of the National Advisory Committee for Aeronautics. in studying hi-speed aircraft, are convinced that the present all-metal plane, of semi-monocoque, aluminum alloy construction, is not the ultimate in aircraft design. Magnesium alloys and steel are under consideration.

Jan 1, 1942

By J. Sadaki, G. Dodbiba, S. Murakami, T. Fujita, S. Matsuo, H. Ono, K. Okaya

Printed circuit boards (PCBs) from discarded personal computer (PC) and household appliances were crushed by mechanical crushing or water explosion to remove mounted parts. More parts were stripped from PCB for PC composed of epoxy resin than from PCB for household appliance composed of phenol resin. In an attempt to raise the copper grade of PCB by removing other components, a carbonization treatment was investigated. The crushed PCB without surface-mounted parts was carbonized under a nitrogen atmosphere at 1073K. After screening, the char was classified by size into oversized pieces, undersized pieces and powder. The copper foil and glass fiber pieces were liberated and collected in undersized fraction. The copper foil was liberated easily from glass fiber by stamping treatment. On the other hand, tantalum capacitors were collected from mounted parts. The tantalum-sintered bodies were separated from molded resins by heat treatment at 723 to 773K in air atmosphere and screening of 0.5mm. Silica was removed and 70% of tantalum grade was obtained after more than 823K heating and separation.

Jan 1, 2011

By Q Qu

Reliable prediction of longwall gas emission sources and rate plays a critical role in mine ventilation and methane drainage capacity planning. Over the years, Australian longwall mines have been using the historic Winter method and the Flugge method in modelling specific gas emissions (SGE). The predicted results often experience high discrepancies from the operational reality. To improve gas emission prediction, post-mining gas contents were measured in several mines in Qld and NSW by safely drilling core holes into the longwall goaf. The results revealed many new insights into gas emission characteristics from different coal seams and the drawbacks of the European methods in their use in high-production gassy Australian longwall mines. Based on measurement data, a new, time-dependent gas emission prediction model has been developed. Considering several factors such as caving, desorption and production rate, the new model can predict more accurate and meaningful gas emissions to meet today’s needs in mine gas emission management. A case study is provided to demonstrate the application of the new SGE model.

Oct 12, 2022

By M Barley, C A. RosiFre, L Lobato

The Carajßs iron ore deposits contain approximately 17.5 billion tons of ore with >64 per cent Fe and occur in the eastern part of the Amazonas Craton. They are hosted by jaspilitic banded iron-formation (BIF) of the Carajßs Formation which, together with metavolcanic rocks, comprise the ~2.75Ga Grpo Parß Group of the Itacai·nas Supergroup in the ~1000 km long, E-W trending Carajßs Synclinorium. The Carajas Formation comprises discontinuous layers and lenses of partly dolomitised BIF (17 - 43 per cent Fe and 35 - 61 per cent SiO2) and lenses of high-grade iron ore, cut by mafic sills and dykes. The high-grade iron ores occur as large tabular bodies of friable (soft) hematite with smaller lenses of hard (compact) hematite. The hard hematite ores typically occur at the contact with the underlying volcanic rocks and are surrounded by an aureole of hydrothermal carbonate alteration. BIF that has been overprinted by dolomite and magnetite crystallisation has recently been discovered at depth in the N4E Mine. With increasing amounts of carbonate, the original lamination (microbanding) and other fine primary structures in the BIF have been progressively obliterated resulting in alternating carbonate and iron oxide mesobands. The friable hematite ore that is characteristic of the Carajßs deposits results from ongoing weathering and leaching of the carbonates from this type of altered BIF. The hard hematite ores probably result from more extensive early oxidation. The association of both carbonate-altered and jaspilitic BIF with the N4 Mine is similar to that observed at the Mount Tom Price deposit in Western Australia, where carbonate-altered BIF occurs below massive hematite ore with a jaspilitic halo developed above the orebody. This indicates that as at Mount Tom Price, hydrothermal carbonate alteration and associated loss of silica from BIF may be an important step in the formation of these giant hematite deposits.

Jan 1, 2002

By A. C. Ross

"The paper will deal with non-destructive testing in general, and its advantages to those responsible for the maintenance of wire rope. An outline of the main features of the M.D. 6 Defectograph will be given, and the method of operation and results obtained will be described.The instrument will accommodate ropes at 7 /16-to 2 %-inch diameter at reasonable speeds, and is capable of detecting the most minute defects in even the largest-diameter wire ropes."

Jan 1, 1969

By J P. van Dyk

The dramatic strengthening of the rand against the dollar as well as a decline in quantity and quality of locally available concentrates have had a dramatic impact on Zincor?s operations during the previous two years. Zincor has responded with the implementation of a number of technical improvements to the process to decrease cost and increase revenue and plant flexibility. Among the initiatives is the pre-leaching and pelletising of the zinc concentrate, de-bottlenecking and process improvements in the leach and purification circuits, the introduction of cathode washing and automated cathode stacking in the cell house and the installation of a new furnace to produce pre-alloyed jumbos. This paper will describe these initiatives and others that Zincor have recently taken to stay competitive in changing global base metals market.

Jan 1, 2005