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By A. Karadogan, G. Tuncer, A. Kahriman, S. Gorgun

This paper presents the results of ground vibration measurements induced by blasting operations at five different sites located close to the residential areas. Within the scope of this study, ground vibration components were measured for all blast events over a long period of time in order to predict peak particle velocity and determine the slope of the attenuation curve for five sites. During the study, while the parameters of scaled distance were being recorded carefully, suitable monitors for all blast events of five blasting sites measured the ground vibration components. At the end of evaluation of the data pairs, an empirical relation, which gives an average line at 95% confidence level, and upper bound 95% prediction line with a good correlation coefficient was established and suggested for each site

Jan 1, 2003

By C. R. Stephan

Explosion-resistant seals in underground coal mines isolate the environment within the sealed area from the active workings of the mine. The current United States Title 30 Code of Federal Regulations (CFR) requires these seals to be constructed of solid concrete blocks. The CFR also allows for alternative methods or materials to be used to create a seal if they can withstand a static horizontal pressure of 138 kpa (20 psi), provided the method of installation and the material used is approved in the ventilation plan. The purpose of this report is to identify those explosion- resistant seals that have been tested and meet or exceed all the requirements of the CFR.

Feb 24, 1997

By R. E. Gilchrist, R. F. Nielsen

When a gas is displaced by mother in a porous medium, and there is a relative immobile liquid present. there is a transition zone in which the gas composition varies from essentially that of the original gas to that of the injected gas. The change in extent of this zone with time may be governed by a mixing process in the direction of flow and by the rate of establishment of gas-liquid equilibrium, if the gases are appreciably soluble in the liquid. The relative importance of these two factors in deterri~ining the growth of the transition zone is discussed, with appropriate equations and experimental data. INTRODUCTION The various solution methods of oil recovery involve a transfer of the components of a mixture, whether within a single phase or between a liquid and gas. The similarity of a natural porous medium to systems used in separation and chromatographic processes makes it seem reasonable that certain concepts used by chemical engineers in "mass transfer" might be applicable to petroleum reservoirs. One approach, the HETP (height equivalent to a theoretical plate), involves a distance or length of time over which equilibrium might be con. sidered as established. Another approach involves direct use of a rate of mixing or rate of establishment of equilibrium. The latter approach has been preferred in relation to production problems. DISCUSSION AND PROCEDURE When a gas or liquid in a porous medium is displaced by one of different composition but miscible with it there will be set up a transition zone in which the composition varies from cssentially that of the original fluid to essentially that of the injected fluid. If the fluid being displaced is a gas, and there is a relatively immobile liquid present, the transition zone may be

By Lutz Markworth, Fernando Parra, Wolfram Jaspers

"The worldwide demand of iron ore and the depletion of the high-purity deposits make it necessary to recover ores in increasingly fine size fractions or low Fe content in the feed material. Impurities for Iron ore processing plants are mainly Silica, Al2O3 and Sulfides.There is a copper processing plant in Chile, which has a high content of Fe in its tailings. These tailings will be re-processed to recover the Fe and to produce a pellet feed concentrate. This challenging flotation process was developed by the customer in his own laboratory. Different flotation technologies were tested. The best results were achieved with the PNEUFLOT® (PNEUmatic FLOTation). For a feed capacity of approximately 600 t/h, a flow sheet of two flotation lines with a reverse two-stage Amine-Silica flotation followed by a single stage reverse Xanthate Pyrite flotation was developed.Because of the two impurities the process control is very critical. Not even the reagent dosing has to be flexible for changes in the feed material; also the flotation cell has to be adaptable. Continuous development of the PNEUFLOT® cell with their specific advantages and the elimination of dysfunctions in the PNEUFLOT® cell have led to a growing demand of this type of equipment worldwide for the iron ore industry within the past years.INTRODUCTIONThe worldwide increasing demand of iron ore is mainly caused by China. This has a major impact on all economics worldwide as the metal price indicates. However, not even the iron ore and steel price, but all other commodities prices and the precious metals prices are increasing by a high percentage. Figure 1 shows the iron ore (pellets) price increase for Fe and the import of iron ore by China. Figure 2 shows the imports of iron ore to China."

Jan 1, 2008

Alluvial gold was found in the Terawhiti area, West of Wellington, in the 1850s. This led to the discovery of reef gold. Periods of minor 'gold fever', company flotations, and mining activity occured between 1869 - 1973, 1881 - 1986, and in the late 1880s, with one final company active in 1911 - 1914. 1n the early 1980s, further field work was carried out. No viable mining operations resulted from any of this activity.

Jan 1, 1993

By K. T. Lee, M. U. Ozbay, M. D. G. Salamon

Design of yielding chain pillars in deep coal longwall mines is not as well established due mainly to the lack of knowledge in the behavior of coal pillars in the post-peak regime. This study shows that two of the existing strain-softening models have the potential to provide an improved understanding of yielding and, therefore, could form a rational basis for yielding coal pillar design. Analytic and numerical modelings of a row of chain pillars in a two-entry development at a depth of nearly 700 m suggests that yielding pillars are feasible, but the design is very sensitive to the coal’s post-peak behavior.

Jan 1, 2001

By G. F. Butterworth

The metallographic structures most frequently encountered in rifle barrels, and which are illustrated by the accompanying photomicrographs, fall naturally into two groups, distinguished by the method used to, produce in the stock a physical condition having the requisite properties. The fist group consists of "rolled" barrels; that is, barrels subjected to hot working by rolling in or near the critical range. In the second group, the stock, which is smaller in diameter than the first, is upset to form the butt end and is then heat treated by giving it a quench and a draw. These barrels will be referred to as " heat-treated " barrels. The structure of the rolled barrels resembles closely that of the same steel after annealing. There is the same network of excess ferrite outlining the grain boundaries, but the grains themselves are composed of sorbite rather than pearlite. The grain size is closely related to the rolling temperature. The critical-point curves of this grade of steel, which is approximately 0.50 to 0.60 per cent. of carbon and 1.00 to 1.30 per cent, of manganese, show a single very pronounced point between 1300" and 1350" F. (704" and 732" C.). Barrels rolled within this temperature range give an exceedingly fine grain, shown in Fig. 1. In fact, the grains may be so fine that, at a low magnification, they may be confused with the heat-treated structure shown in Fig. 6. A magnification of 500 diameters, however, will always resolve a rolled barrel into the characteristic structure shown in Fig. 2. As the temperature is increased, the grains are found to be larger. If, on the other hand, the rolling temperature is below the critical range, the structure previous to rolling will not be obliterated, the only effect of rolling being to elongate the coarse sorbite grains in the direction of rolling, Fig. 3. This distortion is greatest at the muzzle. Heat-treated barrels are quenched in oil from above the critical range, which should give a martensitic structure, Fig. 4, but the presence of some troostite in the martensite is frequently noted when the quench has not been sufficiently drastic, Fig. 5. The structure brought about by the subsequent draw is not so striking, though quite as typical. It is sorbitic or sorbito-pearlitic, and under a low magnification appears almost homogeneous, as in the case of fine grains of pepper and salt well mixed together, Fig. 6. This structure is substantially the same for all

Jan 1, 1920

By S. Ralph Austin

Emanation coefficients of 950 samples of domestic uranium ore were successfully and rapidly determined with fair precision by modifications of the closed-can, gamma-only assay method, using commercially available or similar equipment. Coefficients range from <1 to 91 percent. Emanation varies considerably within each mine and area, but distinct differences among major mining areas were found, ranging from 7.5 percent for Moss Back Member, Chinle Formation, Southwest Lisbon Valley, Utah, to 56.6 percent for Ft. Union Formation (?), Powder River Basin, Wyoming. Coefficients also vary with (1) uranium mineralogy; (2) radium mineralogy; (3) lithology of host rocks; (4) grain size of uranium and radium minerals; (5) comminution of ore; (6) estimated porosity and permeability; (7) moisture content; (8) ore grade; (9) supposed mobility of deposits; age of deposits is unknown but limited by (10) age of host rocks which shows only doubtful correlation with emanation. Data obtained may be used to evaluate effects of investigated parameters on radon concentration in mines and thus to select efficient control measures. Drill-core emanation data allow estimates of probable radon problems in undeveloped deposits.

Jan 1, 1978

The Bureau of Mines has reviewed those portions of the "Tariff Schedules of the United States Annotated 1963" that are of interest to the minerals industry. This study shows to what extent rates of duty were altered (increased of decreased), and provides a bridge where possible from the old Schedule A classification system to the new TSUS system of statistical reporting of import data. In general the new tariff has corrected previous classification defects and inconsistencies, but the rates of duties have not been materially changed.

Jan 1, 1965

By L. J. Heaslip, J. M. Toguri, T. R. Meadowcroft, R. L. Addinall

"""Pilot Plant Operations"" is a final-year core course given to the Metallurgy and Materials Science students at the University of Toronto. This course involves a laboratory study of an industrial project at an industrial site. Details of this program are discussed and reviewed after eight years of experience. IntroductionEducators in the field of Metallurgy and Materials Science have long agreed that ""hands-on"" experience is an important component in the education of metallurgical engineers. This philosophy is reflected in the undergraduate curricula of most metallurgical schools. The major problems encountered with laboratory-associated courses are the requirements for equipment, space and funds for both purchase and maintenance of equipment. For example, consider an exercise in crushing and grinding treatment in a mineral processing laboratory. Such operations require the handling of tons of material and often equipment of large size. The problems of storage of ore, methods of handling and maintenance of equipment are a few of the concerns facing the department. Considering that metallurgical departments at universities are, in general, relatively small, the support to purchase and maintain largescale equipment becomes an annual budgetary concern. In reality, universities today are not geared to operate mini-pilot plant equipment, either in terms of space or personnel.For the above reasons, in 1972an undergraduate core course called ""Pilot Plant Operations"" was introduced to the fourth year curriculum in Metallurgy and Materials Science at the University of Toronto. This course consists of I to 2 full weeks (8 hrs per day) of pilot plant laboratory study at an industrial site on a project of mutual interest with the industrial organization whose facility is being used. The first 5 years of the program were carried out at the pilot plant facility at the Ontario Research Foundation; Stelco&apos;s Research Centre in Burlington, Ontario, was used for the last 3 years. The nature of the projects undertaken during the 8-year period is shown in Table 1."

Jan 1, 1980

By R. Stefanko

This first Annual Report covers the work on Contract No. H0377043 "Cable for Face Equipment", from August 1, 1977 to July 31, 1978. It reports the progress in the three areas of over-and short-circuit protection, cable ampacity research and cable couplers. Field trips have established many interesting facts related to circuit breaker settings and cable size. For example, the determination of cable sizes depends on the RMS duty cycle current determined by a particular piece of equipment, but the actual selection of the cable to be used is often a function of the maximum allowable circuit breaker instantaneous settings as specified in Title 30. In order to avoid nuisance tripping as a result of instantaneous starting current field, laboratory and analytical studies are being conducted to determine proper settings and cable sizes Also an extensive program has been established to monitor the performance of high voltage cable couplers and determine their modes of failure. Various equipments are being designed for laboratory testing, and an extensive reeled cable experiment is also under way.

Jan 1, 1978

By David A. Hill

This volume contains a summary of the results of past analyses on U.S. Bureau of Mines Contract No. 80122061 which are relevant to electromagnetic location in mine rescue situations. The analytical results indicated that detection of a trapped miner equipped with a special transmitter is feasible in most situations. Location of the miner by surface measurements is also generally feasible within certain errors. The feasibility of miner detection and the accuracy of miner location have been examined theoretically for a wide variety of situations. Agreement with experimental results is generally good in cases where measurements are available. Personnel involved in the investigation include J.R. Wait (Principal Investigator), D.A. Hill (Co-Principal Investigator), K.P. Spies, A.Q. Howard, and Lana Slusher (Administrative Assistant).

Jan 1, 1974

By R G. Skirrow, M Cooper, J Claoué-Long, K Czarnota, H Dulfer, J Thorne, D C. Champion

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. Tholeiitic intrusion-hosted nickel (PGE-Cu) sulfide deposits are under-represented in Australia’s inventory of known resources of this deposit type, relative to regions globally with comparable geology. To support discovery of major new deposits, a continental scale analysis of Australia’s potential for tholeiitic intrusion-hosted nickel (PGE-Cu) sulfide deposits is being undertaken. The analysis applies a mineral systems approach to map the four essential components of the ore-forming systems:1. sources of ore constituents2. crustal and mantle lithospheric architecture3. energy sources or drivers of the ore-forming systems4. gradients in ore depositional physico-chemical parameters.The results reveal several regions of Australia with potential for discovery of large tholeiitic intrusion-hosted nickel (PGE-Cu) sulfide deposits, mostly around the margins of Archean and Proterozoic lithospheric blocks. These include the south-east and northern margins of the Yilgarn Craton, the south-west and south-east margins of the Kimberley Block, the southern margin of the Arunta Province in central Australia, the western flank of the Gawler Craton in South Australia, and possibly some areas within the Palaeozoic Lachlan Orogen of eastern Australia.CITATION:Skirrow, R G, Dulfer, H, Czarnota, K, Champion, D C, Thorne, J, Cooper, M and Claoué-Long, J, 2015. Australia’s potential for nickel sulfide ore systems – a new continental-scale time-space framework for exploration, in Proceedings PACRIM 2015 Congress, pp 679–684 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By H. H. Dewing

The Bureau of Mines constructed a process research unit (PRU) to demonstrate new technology for extracting zinc from sphalerite concentrates. Up to 9 kg/hr of sphalerite (ZnS) concentrate was reacted at ambient pressure in the PRU with 80 pct sulfuric acid at 160° to 180° C to produce zinc sulfate and elemental sulfur. The PRU consisted of a three-stage glass reactor system: a 4-liter premix stage in which feed was slurried with 78 to 82 pct H2S04, a 40-liter stirred reactor, and a ISO-liter settling stage in which high reaction conversions were effected and excess H2S04 for recycle was separated from insoluble ZnS04 and sulfur. Evolution of sulfur-containing gases was minimized by sub-surface addition of acid feed slurry to the stirred reactor and by exclusion of air from the reactor to prevent the oxidation of elemental sulfur. Conversion of zinc to zinc sulfate averaged over 99 pct at the optimum acid concentration of 80 pct. Total sulfur losses (primarily S02) were less than 2 pct of the sulfur in the sphalerite. Elemental sulfur remained in the insoluble portion of the settled reactor product after leaching with simulated spent zinc electrolyte containing sulfuric acid. The sulfur residue contained 75 to 89 pct sulfur. Neutral zinc sulfate, required for zinc electrowinning processes, was separated from the sulfuric acid leach solution by crystallization at -15° C as zinc sulfate heptahydrate (ZnS04?7H20). The crystallization operation simultaneously effected a partial concentration of the recycled electrolyte solution by removing water.

Jan 1, 1982

The Hyde-Macraes Shear Zone (HMSZ) is low angle, duplex thrust system that has developed in a graphitic pelite schist within the Otago schist belt, New Zealand . At Round Hill lateral ramps have developed parallel to the movement direction between+ the footwall and hangingwall shears. These structures exhibit normal oblique-slip displacement which has been an important mechanism for creating space in an otherwise compressional system. Gold-bearing quartz veins were emplaced along the boundary shears and lateral ramps during thrusting. Gold within the lateral ramps is coarse (up to 300 microns) however hanging wall cataclasite development in the boundary shears after the gold was deposited has reduced the grainzise of most of the gold to less than one micron. This bimodal gold distribution has metallurgical implications with respect to the maximisation of gold recovery at Macraes.

Jan 1, 1993

By Hui Yongning

This paper presents a simulating test of constitutive relation of soil anchor in laboratory and puts forward a new plastoelastic mechanical model, on which a new calculating formula of elastic and plastic limit bearing capacity for soil anchor is suggested and two engineering projects verify that this method is adaptable.

Jan 1, 1991

By D. Van Tonder, C. Edwards

ABSTRACT Solvent extraction is used in many acid leach uranium circuits to upgrade and purify the uranium-bearing solution prior to final product precipitation. A number of strip options are available to recover the uranium from the loaded organic. This paper compares seven of these options on the basis of typical capital and operating costs for the solvent extraction circuit and downstream uranium processing and also considers other related issues. The aim is to provide an objective comparative assessment of these options that could be used as a qualitative guide in process selection or improvement.

Jan 1, 2013

By F. W. Bowdish

Analysis of data on the equilibrium exchange of sodium ions from salt solutions for calcium ions, from various fractions of an oxidized calcareous iron ore from Lorraine, France, strongly suggests that the calcium may be attached to the solid by only one of its bonds. Nearly equal values were found for the equilibrium expression from data covering concentration ranges of 1000 fold for the salt and 235 fold for the ion-exchangeable calcium. Differences indicated between the exchangeable calcium contents of the slime and the sandy portions of the ore, as well as the equilibrium relationship itself, are of importance in the flotation of the ore. During an experimental program on the flotation of oxidized calcareous iron ores from Lorraine, France, ion-exchangeable calcium was found in the ore. Because this source of calcium ions, if not controlled, could thwart all efforts at flotation, an extensive study was made of the phenomenon. The part of that study reported here was to obtain data on the equilibrium established between ore solids and solutions of sodium chloride, and to analyze the data to try to understand better the physical chemistry of the exchange. The ore contains oolites of goethite and quartz grains embedded in a matrix consisting of calcite and a brown cement believed to be the residue from oxidation of the silicate minerals found in fresh unoxidized ore. When ground, a substantial fraction of the ore becomes a fine slime in which is concentrated more than half of the alumina content of the ore. It is believed that the alumina occurs as unidentified clay minerals with which most of the ion-exchange capacity of the ore is associated. A preliminary experiment on the exchange of ions from the ore for sodium ions from solutions of NaCl showed that calcium was about ten times as abundant as magnesium in the exchange solutions. Thus calcium was the predominant ion in causing difficulties with flotation, and it was the only one for which data was obtained in this study. It is believed that the omission of magnesium ion exchange from consideration does not invalidate the results. It is possible, however, that inclusion of magnesium in the analyses and calculations or its prior elimination from the samples would have improved the consistency of the results. EXPERIMENTAL Data about the equilibrium exchange of sodium from solutions for calcium from the solids were obtained using two different samples of material. The solids

Jan 1, 1963

By Donald A. Bruce

The paper reviews aspects of the construction and performance of prestressed ground anchors installed in soils and weak rocks. Attention is focused on good practice for drilling, tendon fabrication and handling, grouting, stressing and testing. Regional variations - not always logically justified - are described. The performance of anchors in a variety of geological conditions is illustrated with reference to recent full scale test programs. 1. Introduction In the United States there has been steady growth in the use of prestressed anchors in materials other than competent or hard rock, in the years since their introduction in the late 1960&apos;s. This expansion has to a large extent been driven by specialty geotechnical contractors who both imported foreign developments and conducted their own basic researches, in locally prevailing conditions. With such data and experience, these engineers have had the confidence to promote "alternative solutions" for difficult earth support problems to receptive designers and owners. In turn, being engaged in the details of design and performance monitoring has given these parties the close exposure necessary for the real transfer and understanding of the technological concepts, and this knowledge has generated positive feedback for the contractors.

Jan 1, 1991

By R. Hardy

LaModel is a boundary-element program capable of calculating the displacements and stresses in thin bedded deposits such as coal, salt, or potash. Throughout its history, it has continually been upgraded in order to expand analysis detail and stay current with the latest advances in computer technology. The most recent enhancements include: an increased grid size capability, a significant increase in the speed of the automatic grid generation using an AutoCAD visual interface, implementation of subsidence-based horizontal strain calculations for multiple-seam situations, and pillar safety factor calculations. To demonstrate these new features, a multiple-seam case study of a longwall panel undermining an active set of main entries is presented.

Jan 1, 2006