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By Caisa Samuelsson

Experimental studies in laboratory-scale equipment have been carried out to study the vaporisation from dust generated during the copper converting process. In the present work the vaporisation of Zn, Pb, As, Sb, and Bi from a dust collected in the electrostatic precipitator after the copper converter were studied. The results show that Pb, Bi and As were vaporised to a high degree from the dust at a temperature above 900°C in a gas containing N2, SO2 and a small amount of H2. The vaporisation was high for these elements also in a gas containing N2, SO2 and 02 at temperatures above 1120°C. In an earlier study, thermodynamic calculations showed that it is possible to selectively condense metals at high temperature' in a gas atmosphere generated during a copper converting process. The present study was carried out to verify the thermodynamic model. The results indicate that it should be possible for a selective condensation of Zn at high temperature. The temperature required for a selective condensation of Zn is dependent upon the gas atmosphere, e.g., the oxygen potential.

Jan 1, 1998

By Albert L. Toenges, Louis A. Turnbull, Henry E. Dekay, James N. Scudder

A preliminary survey of coke and steel plants conducted by the Bureau of Mines in cooperation with the Office of Solid Fuels Coordinator and under the auspices of the Coke Production Committee indicated that a very appreciable increase in pig-iron production would be obtained if pres- ent blast furnaces were supplied with a more uniform coke. Control of the sulfur and ash content of coal used for making coke is an important factor in producing uniform coke and thus increasing blast- furnace efficiency. In some mines producing metallurgical coal, the analysis of the coal bed shows a wide range of sulfur and ash content. To obtain production of coal with minimum deviation in sulfur content sampling, grading, selective mining, blending, and surface preparation are practiced at some mines with satisfactory results. The mines selected for this study have developed these methods and are successfully producing coal of uniform sulfur and ash content. The systems employed at different mines vary according to the physical character- istics of the coal bed, the manner of occurrence of impuritites in the coal, the development plan and mining system, surface preparation and the acceptable impurity content of the prepared coal. The ash content of the coal can be controlled by face preparation and in the cleaning plant. The introduction of some method or practice at other mines might make possible the use of coal for inetallurgical purposes that otherwise could not be used for making coke because of the wide variation of sulfur and ash content.

Dec 1, 1943

By Ernst Lindemann

Steel suppliers are required to deliver sheets with particular qualities and with lightweight-potential to the automotive industry. New types of steel call for new production processes. SMS group has developed a new micro-mill-concept, the core of which is the belt caster. This was first built on an industrial scale and has been put into operation and developed together with Salzgitter Flachstahl GmbH. The robustness in industrial-scale operation could be verified. The full use of the belt casting technology, mainly related to energy efficiency and CO2 reduction, is realized with the micro-mill-concept. This is an in-line-process, casting and rolling in one line.

Aug 17, 2017

By William J. Campbell

These investigations were undertaken as part of a program to determine the optimum X-ray spectral lines to use for analyzing the wide variety of samples received by the X-ray Laboratory. Theoretical calculations and experimental data derived from these investigations show that longer wavelength spectral lines, > 2A, are very useful for many analytical problems. Because of the low fluorescence yield of the elements of atomic numbers 13-22 and the small depth of penetration of their X-ray spectral lines, these elements were originally considered to be insensitive; however, these studies show that the wide dispersion of their spectral lines, coupled with their weak beta lines, permits the use of wide collimation, thus increasing the line intensity. More importantly, the background due to scattered primary radiation is very low in the long-wavelength region.

Jan 1, 1959

By Steven J. Page

Responding to the increasing concern for dust control in metal and nonmetal mining, the Bureau of Mines investigated typical dust reduction efficiencies of wet bar cutter machines as they are presently being used in salt mines. Wet bar techniques have previously been used in coal mines, achieving dust reduction efficiencies ranging from 11 to 60 pct. Two different wet bar techniques, namely, the front spray and the water trickle, have been studied as they are currently being used in two salt mines. Preliminary results show that the dust reduction efficiencies have a large variation (0 to 66 pct), as is the case for wet bars used in coal. However, whereas wet bars in coal required 3 to 4 gpm water consumption, wet bars in salt obtained similar efficiencies with only 0.1 to 0.4 gpm. The most reliable data obtained during this study show that the front spray system consistently performs at efficiencies between 41 and 66 pct, with an average of 54 pct. The results indicate that, although wet bar cutter techniques in salt mines are a relatively simple and inexpensive means of dust control with a minimum of water consumption, further investigation should be performed to fully evaluate and optimize wet bar cutter dust reduction efficiencies.

Jan 1, 1980

By Samuel J. Sims

The Grace mine magnetite deposit, located 2 miles north of Morgantown in Berks County, Pennsylvania, was discovered in 1948 by an aerial magnetometer survey. It is situated on the southern border of the Triassic lowlands section of the Piedmont province. Cambrian sandstones, shales, and limestones overlie Precambrian crystalline rock and were folded and thrust-faulted during the late Paleozoic Appalachian revolution. Late Triassic continental sediments were deposited on the deformed basement rocks and were intruded by Late Triassic diabase dikes and sills before regional tilting and normal faulting occurred. The Grace mine magnetite ore is characteristic of the Cornwall type. The ore has replaced a Cambrian limestone lens isolated between Triassic diabase footwall and Triassic sedimentary rock hanging wall. The ore body is roughly tabular in shape, dips 20° to 30°NE and plunges about 20°N80°E. The ore is granular, fine- to medium-grained, typically consisting of unevenly distributed magnetite in a matrix of light green to white serpentine gangue. Magnetite is the major ore mineral, pyrite and chalcopyrite are common accessory minerals, and pyrrhotite occurs locally. Sphalerite, marcasite, galena, hematite, digenite, and goethite are uncommon. Serpentine, talc, and chlorite are the major gangue minerals; calcite and dolomite are common, and phlogopite, tremolite, and biotite are present locally. Apatite is a common accessory; sphene is rare. Calcium-magnesium silicates were formed first by contact metamorphism of impure limestone by the intruding diabase. Later, the silicates were altered hydrothermally to the serpentine- talc-chlorite assemblage now present. Magnetite, the first ore mineral, formed by replacing serpentine and was followed by pyritepyrrhotite and then by chalcopyrite-galenasphalerite. Marcasite, secondary pyrite, goethite, and hematite are secondary minerals resulting from alteration of pyrrhotite and magnetite. It is estimated that confining pressure was about 1500 bars and the temperature range was 500° to 675°C during ore formation.

Jan 1, 1968

By P. K. Kaiser, M. Cai

When designing an efficient and effective support system for burst-prone ground, it necessary to select the most appropriate, i.e., the ‘right’ support components, including areal and reinforcement components. For this paper, it is assumed that the areal support is not the weakest link and the support performance is controlled by the rock reinforcement and holding components (bolts). We discuss the loading modes of rockbolts under static and dynamic loadings and analyze published data from laboratory and field tests. The mechanisms of energy absorption of dynamic rockbolts are presented and rockbolts are categorized based on factors such as energy absorption capacity, energy absorption rate, direct and indirect energy absorption capacities, rock mass bulking or displacement control, and shearing resistance capacity. Guidelines for selecting the ‘right’ rockbolts to build an effective rock support system for burst-prone ground are provided.

Apr 26, 2022

By Jr. Watts, B. K. Cantrell, K. L. Bickel, J. F. McDonald

"A field trial was conducted at an underground gold mine to evaluate diesel fuel derived from soybean oil (soy-methyl-esters or “biodiesel”) as an alternative to commercial, low-sulphur, number 2 diesel fuel (D2). A 2.7 m3, 18-ton load-haul-dump (LHD) unit, powered by a naturally aspirated, indirect injection (pre-chamber), 100 kW diesel engine was used as the test vehicle. The LHD was equipped with a diesel oxidation catalyst. The LHD operated satisfactorily on the biodiesel fuel. Operators observed a slight decrease in power and an absence of black smoke.Diesel particulate matter (DPM) concentrations were monitored for a six-week period while the LHD was operated with either the biodiesel fuel or the D2 fuel. DPM concentrations were measured in the mining section’s clean air intake, exhaust and on the LHD. Reduction in DPM emissions was determined from the measured difference in DPM concentrations between the clean air intake and the exhaust. The biodiesel fuel reduced energyspecific DPM emissions approximately 75%, from 3.6 ± 1.8 g/kW-hr to 0.86 ± 0.27 g/kWhr. Time-weighted average DPM exposure, measured near the LHD operator, was reduced from 0.67 ± 0.13 mg/sm3 to 0.28 ± 0.12 mg/sm3, or approximately 58%, when the biodiesel fuel was used. IntroductionDiesel exhaust consists of noxious gases and diesel particulate matter (DPM). Recent attention has focussed on the potential carcinogenicity of DPM and the potential health impact on miners. The National Institute for Occupational Safety and Health (NIOSH) recommended that whole diesel exhaust be regarded as a “potential occupational carcinogen”, and that reductions in workplace exposure would reduce cancer risks (NIOSH, 1988). The International Agency for Research on Cancer (IARC) declared that “diesel engine exhaust is probably carcinogenic to humans” (IARC, 1989)."

Jan 1, 1997

By Carlo Massa

THE Societá Auonima di Miniere e di Alti Fourni, familiarly known as the " Elba Company," works the rich ore-deposits of the Island of Elba under a long-term contract with the Italian Government. The ore-deposits are scattered over the eastern and southeastern coast; but as those parts of the island are not well provided with ports, the blast-furnaces were built at Portoferraio, the principal town of the island, situated on the northern shore, and possessing a magnificent natural harbor where even vessels as large as the battleships of the Italian navy can comfortably anchor. In the selection of Portoferraio. the cost of transporting the iron-ore from the different mines to the blast-furnaces has been reduced to a minimum, and shelter has been provided for the Company's flotilla of tugs and barges, as well as for the steamers carrying coal and pig-iron. The whole plant, of which a general view is given in Fig. 1, comprises 1. A discharging-pier with unloading-cranes. The ore and coal are transported from this pier by means of an aerial cable-rail¬way to the coal- and ore-storage yards. This cable-railway is supported by an iron bridge extending from the pier to the shore and by a wooden trestle extending from the shore to the yards. , 2. Blast furnaces, two in number, with all the accessory appa¬ratus, such as blowing-engines, dry purifiers, Cowper hot-blast stoves, hoists, etc. 3. Coke-ovens, two batteries, with coal-bin, crushers and boilers. 4. Engine-house containing the blast-engines and the electric generating-station. 5. Pumping-plant. 6. Narrow-gauge railways.

Mar 1, 1905

By B Murphy

Safescape Laddertube provides an improved system for emergency egress in ventilation shafts. The addition of Laddertube in a rise has very little impact on ventilation flow, studies have indicated that the difference in flow velocities are difficult to measure due to the minimal impact. Due to the size and open-ended nature of Laddertube, the air velocity inside and out of the Laddertube is mostly linear. Laddertube can be used either permanently or during an emergency as a secondary ventilation duct. One project involved a 385 m ladder installed in a surface return air raise that could be made to bypass the primary circuit and supply fresh air to a sea container fresh air base at the bottom of the raise. Laddertube has been designed to be installed to any feasible length and can be fitted with a climb assist system ensuring enhanced speed and reduced fatigue during ascent. The climb assist used in association with Laddertube is a Tractelift system which applies a weight relief of up to 36 kg off the climber’s body weight when using the ladder. This system has successfully been tested for ladders up to 600 m in length and is currently in use for a ladder of 185 m length. The use of refuge chambers in underground coalmines has long been a contentious issue due to the concern that while it may provide temporary shelter, the risk of being exposed to high heat or the inability for rescuers to access them due to fire or explosive atmosphere means that they may be effectively trapped. The additional application for coal environments includes Laddertube installed alongside a refuge chamber concealed behind a blast proof door ensuring a secondary means of emergency egress. In certain operations designs may allow for this chamber to be provided withpositive pressure fresh air.

Oct 12, 2022

By F. T. Cawood, T. Chikande, H. R. Phillips

Underground mines require electricity to operate both the main surface fans and auxiliary systems, with primary ventilation systems typically accounting for approximately 40–60% of the mine’s overall electricity consumption. The primary reason for this considerable expense is that most underground ventilation systems are designed for peak demand, regardless of the actual demand, which is commonly dictated by diesel equipment usage in trackless mining operations. Most platinum mines on the Great Dyke in Zimbabwe tend to operate their ventilation systems at this peak level, despite the mine’s air quantity being well in excess of the ‘true’ ventilation needs. This is due to a lack of appropriate ventilation controls. The authors designed and installed a ventilation-on-demand system at one of the bord and pillar platinum mines to minimize the use of redundant air in underground operations. Fourth industrial revolution techniques were applied to the environmental monitoring and tracking systems thereby optimizing air quantity demands. The mine managed to reduce its annual power consumption by 23% through the implementation of manual control and time-of-day scheduling levels of the ventilationon- demand concept. There was also a 6% productivity improvement, mainly attributable to an increased face time as a result of the significant reduction in the re-entry period following a blast. This paper introduces a novel concept of ventilation optimization through digital transformation targeting mainly room and pillar platinum mines. A system was designed, installed, and commissioned, though there is currently an ongoing optimization process to harness the full benefits such as productivity enhancement, reduced power costs, and improved worker health.

Dec 13, 2022

By Roderick C. McDonald

Great Bear lake, the fourth largest body of water on this continent, comprises an area of approximately 12,000 square miles, and is set astride the Arctic circle, with a large portion of it witnessing both the Arctic winter night, and the Arctic summer day with its midnight sun. The very name itself, Great Bear, suggests an Arctic region. The seasonal contrasts at Great Bear lake are very marked by the cold and darkness of winter, and the warmth and brightness of summer. Signs of winter such as low clouds, snow, sleet, fog, and night frosts, generally appear the latter part of August, while ice forming on bays during the last two weeks in September ends boat travel on the lake about September 30th.Early in June the ice leaves the river mouths, during the last ten days of the month it disappears from small bays, and at some time during the last two weeks of July the main body of the lake becomes navigable. In 1916, the ice disappeared earlier than usual, and the lake was navigable on July 5th. Great Bear river generally breaks up about June 1st, but, on account of ice cliffs and floes, it is not navigable with safety until early in July. Even then, the traveller is confronted with the Charles rapids, but these might be overcome by a wagon or motor road, such as the one from Fitzgerald to Fort Smith: However, in 1931, Mr. A. W. Boland, Fort Norman, N.W.T., carried with scow and motorboat practically all freight between Fort Norman and LaBine point and Hunter bay, at the east end of the lake. During July and August, two types of clothing are required, for, although the days are mainly ones of warm sunshine, the nights are cloudy and cold. In the winter season, fur clothing is used exclusively. Considerable timber, mainly white spruce, suitable for fuel and building purposes, borders the lake and extends eastward to the Coppermine river. North of the lake, no timber is found except in the river valleys, but with oil and coal possibilities near Fort Norman, the fuel situation might be solved.

Jan 1, 1932

By Floyd C. Bossard

Major air-cooling facilities have been installed and are operating underground in U.S. copper mines (at Butte, Montana and Superior, Arizona), South African gold mines, European coal mines, Zambian copper mines, Kolar gold mints in India, Coeur d'Alene mines of Idaho, plus other locations. Mining districts that utilize spot cooling and local air-cooling facilities would increase the above listing many times. The principal objectives of underground mine air cooling systems are to; 1. Extract heat and water vapor from the mine air and provide for their removal from the mine via (a) water pumped to surface or (b) discharged mine exhaust air. 2. Provide acceptable artificial ambient conditions for efficient working mine development and production areas. 3. Recondition used air, thus supplementing the limited mine ventilation balance. In deep South African gold mines, when rock temperatures exceed about 105°F, cooling of underground air becomes necessary for the poorly ventilated sections of the mine. By U.S. standards, air conditioning in poorly ventilated mines usually commences when the virgin rock temperature exceeds 100°F. On the other hand, well ventilated deep vein-type mines in the U.S. have been able to forego general cooling of mine air until the mines have been extended to such depths that the virgin wallrock temperatures have exceeded 115° - 120°F. It must be noted that spot-cooling of selected development headings may be required in many mines where rock temperatures exceed 100°F. Such local air-cooling practices permit the driving of long headings for exploration or extended development prior to holings which result in establishment of primary ventilation circuitry. The following summary reports on current practices of cooling and dehumidifying mine air. General system descriptions with important details will hopefully permit the reader to gain an understanding of the subject. A list of references is provided for this serious investigator who desires a more thorough knowledge-base and who is responsible for the design of a mine air-cooling system.

Jan 1, 1973

By X Feng, X Zhang, W Sun, Y Zhe, K Hou, B Zhao, H Liu

Pulang Copper Mine, being China's largest newly built mine using block caving, boasts an annual production capacity of 12.5 million tons. Production level and roadway stability hold the key to the successful application of block caving. However, with Tong Kuangyu being the only mine in China which has applied such a method, we currently lack relevant experience in the successful application of the method. This paper has studied the influence of different rock mass zonings, fault thickness, fault dip angles, on-site construction quality on the production level, roadway stability of block caving through numerical simulation and analysed the roadway stability in different kinds of support solutions so as to ensure the successful application of block caving in Pulang Copper Mine. The results have shown that the existing support method in Pulang Copper Mine can meet the requirement of roadway support in zone II and III, but could not satisfy the demand in terms of support strength in the relatively fragmented zone I area. When roadway passes through the fault, the deformation of surrounding rock and plastic zone of roadway will gradually decrease with the increase of fault dip angle; the deformation of surrounding rock and plastic zone of roadway will gradually increase with the increase of fault thickness. An ideal support effect can be achieved through the joint support of grouting and bolting when roadway passes through the fault. In the measured model of on-site construction, there is stress concentration in the intersection between the access and transverse drift of ore removal. Therefore, the stability of the roadway can be improved by improving the construction quality. CITATION:Sun, W, Hou, K, Zhang, X, Feng, X, Liu, H, Zhe, Y and Zhao, B, 2018. Research on supporting technology for production level roadways of block caving in Pulang Copper Mine, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 95–106 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By T. R. A. Davey

Previous publications on the application of EIETSIM include the modelling of an electrolytic zinc plant and a copper flash smelter. In the present case METSIM has been used to model the desilverising of lead by the reagent zinc, whereby a silver-zinc intermetallic compound is formed, and floats out of the lead. This compound has a variable composition, depending upon the ratio of dissolved zinc/silver in the lead bath. Its solubility in lead decreases with falling temperature. A number of variations and modifications of the Davey Desilverising Procedure are modelled, and applied to a wide range of silver contents in lead bullions at several plants. METSIM uses both feed- back and feed-forward controls to simulate plant conditions, and a logic control to distinguish between different phases in the Zn-Ag system. Use is made of extensive (previously unpublished) fundamental data on the ternary Pb-Ag-Zn system, and of plant data, to establish certain operating parameters.

Jan 1, 1993

By Shanjun Mao

This paper summarizes current achievements of Digital Mining in China, puts forward the concept, framework and key technology of Smarter Mining, and finally points out that there is still a long way to go in order to acheive Smarter mining.

Aug 1, 2013

By N. Melnyk, H W. Habgood

The conventional low temperature process for extracting' helium from natural gas involves liquefying the whole gas stream in order to remove the relatively small fraction of helium. A process based on the selective diffusion of helium through a semi-permeable barrier is, in principle, more economical and flexible, particularly for the treatment of small re-serves and low concentrations. The well-known permeability of glass to helium offers the possibility of such a diffusion process and McAfee of the Bell telephone Laboratories showed in 1958 that practical separations could be achieved by passing natural gas over bundles of fine capillary glass tubing. Developmental studies have been carried out involving larger units and more extended field tests than those of McAfee. Fine capillary tubing of Pyrex glass 0.0035 in. diameter was prepared by drawing ordinary 6 mm. laboratory tubing in a furnace. Extraction units were pre-pared containing about 10,000 such tubes, 4 ft. long and cemented inside

Jan 1, 1961

By F. Lowell Lawrance

JOHN SMITH, citizen of the U.S.A., has become so accustomed to reading that Congress has appropriated billions of dollars to pay war costs. that he no longer is impressed by relatively small figures, such as several hundred thousand or a few million, in connection with Government departments.

Jan 1, 1944

By Jorge Alberto Soares Tenório, Denise Crocce Romano Espinosa, Amilton Barbosa Botelho Junior

A new step in the Bayer process has been used to recover NaOH and to reduce its content in red mud. After digestion, the residue is separated from the Bayer liquor and goes through press filters, which enables the recovery of NaOH and decreases the moisture content. It is well known that red mud is one of the most important sources of scandium. For this reason, the goal of this work was to characterize a Brazilian red mud (BRM) for scandium recovery. The sample was collected after the press filter system process. Analysis of energy-dispersive X-ray fluorescence (EDXRF), scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS), and X-ray diffraction (XRD) was performed. Microwave digestion using an acid mixture was carried out to determine the concentration of the main elements. Fe2O3 represented 40% of the BRM, and the Sc concentration was 43 mg/kg. The SiO2 content was 24%, which is the highest value found in the literature, whereas the sodium concentration was the lowest. A literature review was carried out to compare results with BRM, as well as the current studies for recovery of scandium by the leaching/ion-exchange process. Scandium recovery using a leaching/ion exchange process may be possible with efficiency higher than 90%. The greatest challenge is the occurrence of silica gel formation during leaching.

Oct 19, 2020

By C Simpson

In 2011 the forecasted world demand for iron ore continues to grow, and during this time Australia is looked upon as a reliable supplier of high quality ore. The expansion of the current Australian mines is unlikely to meet the forecast demand. New mines are therefore being actively explored for and when discovered, are quickly being developed into mines in order to meet the world’s hunger for steel.The Solomon Project area is a large new iron ore discovery, located in the central Hamersley Ranges of the Pilbara province in Western Australia. The first Fortescue exploration drill holes commenced on the project in 2007 and to date three billion tonnes (Bt) of iron ore have been defi ned within the project area. Fortescue is fast-tracking the development of the ‘Solomon Stage 1’ project, with rail and mine construction commencing during 2011, and ore to be railed to Fortescue’s existing shipping operations at Port Hedland commencing in 2012. At a designed production rate of 60 Mt/a, the Solomon operation will be one of the biggest production centres of iron ore in the Pilbara.Deposit types include the three dominant mineralisation styles of the Pilbara province, being bedded iron deposits (BID), Channel iron deposits (CID) and detrital iron deposits (DID). All these mineralisation styles are present in large concentrations within the Solomon project area, and when mined will produce two product streams. These are a single product of CID, and a combined product from a blend of BID and DID material.This paper defines the geological characteristics of the Solomon iron deposits as recognised through the exploration and development of this vast resource over the three years since exploration commenced on the project.

Jul 11, 2011