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By Shoma Sinha, Nirmal K. Sinha

Deformation in a material at any temperature is known to consist of two major components - a reversible (elastic) part and an irreversible part (often called plastic). What is not universally known is the fact that at high temperatures greater than about 0.4Tm, where Tm, is the melting point in Kelvin, the reversible part includes not only elastic but also a delayed elastic (recoverable but time dependent) component. A very simple computational model is presented here for a constant-strain stress relaxation test (SRT) on the basis of a three-component constant-stress rheological equation derived from strain relaxation and recovery test (SRRT) data. It is shown that the rapid stress reduction during the early periods of relaxation when the stresses are high is governed primarily by delayed elasticity irrespective of the imposed strain level. This is in contradiction to the popular concept prevailing today. The asymptotic approach to a quasi-stable stress rate at longer times and lower stresses is, however, controlled by viscous flow (power-law creep). The validity of the theory is examined by comparing the predictions with experimental results obtained for a titanium-base alloy Ti-6246 at 0.45Tm.

Jan 1, 2004

By E. G. King

This report contains experimentally determined heat-content values for cerium dioxide and Columbium (niobium) dioxide in the temperature range from 298° to 1,800° K. There are no previous similar data for Columbium dioxide, and those for cerium dioxide have an upper limit of 373° K. The heat-content and corresponding entropy-increment data are presented in tabular form. Equations were derived to represent the heat contents and heat capacities. The data for cerium dioxide are entirely regular, but those for columbium dioxide show two previously unreported anomalies at 1,090° and 1,200° K.

Jan 1, 1961

By A. Mortazavi, H. Nasab

"The storage of petroleum products on surface is associated with difficulties and limitations. Accordingly, a viable alternative is to excavate underground space in rock and provide a safe way for oil storage. Soft rocks such as salt domes provide good conditions from environmental and operational points of view. The potential for high-volume storage and low permeability are encouraging aspects for oil storage in salt domes. The complicated shape of oil storage caverns, the complicated behavior of salt rocks, and boundary conditions associated with large underground openings are important challenges in the design of oil storage caverns. The aim of this paper is to delve into the stability and deformation mechanisms of storage caverns created in salt domes. A parametric study of effect of the cavern size, orientation, and depth is carried out as a function of ground stress regime. The stress field and deformation mechanisms are calculated for each case aiming at providing design guideline.INTRODUCTIONOne of the most popular soft rock that is used for underground oil storage is salt rock (halite). Salt rock has particular characteristics which makes it suitable for oil storage. Salt rock has several advantages for oil storage, these are: high production rate, high degree of availability, short filling period, high level of safety and low permeability [1]. The low permeability is due to the fact that halite deforms in a plastic manner over a wide range of pressures, temperatures and rates of deformations. This property prevents joints or gaps opening up in the formation, thus preventing the escape of liquids and gases. The state of stresses around the cavern in salt domes depends on the depth of the cavern (initial stresses and rock mass temperatures are increasing with depth), the in-situ stress state within the rock mass, and the internal oil pressure in the cavern. Furthermore, the salt creep behavior and the cavern geometry are influencing stress redistributions during loading and unloading phases.Rock mass structure, cavern geometry, material behavior and cavern operation patterns require complex physical models to describe the load-bearing behavior of the geomechanical structure. The determination of stress, strain and deformation in the rock mass due to cavern construction and operation are complex problems which can be evaluated employing numerical tools such as the Finite Element Method (FEM) or Finite Difference Method (FDM). In this study, the finite difference method was used to evaluate the behavior of oil storage cavern in salt rock."

Jan 1, 2015

By Etienne S. Bieler

Mr. Chairman, Ladies and Gentlemen, I come to you tonight distinctly as a physicist, not as a geologist or a mining man. My experience in applied geophysics has been short, and I do not doubt that many of you have a much larger acquaintance: with the subject than I have. A little over a year ago, the firm of Alderson, MacKay & Armstrong decided to investigate the possibility of developing a new method of electrical prospecting suitable to our northern Quebec and northern Ontario conditions, and asked me to take up the work. A preliminary survey of existing literature convinced me that the field of induction methods was most promising. I wish to give you some account of the work carried on last summer in the Rouyn district in this connection with the very able assistance of Mr. H. G. I. Watson. Geophysical methods of prospecting can be divided generally into four classes: magnetic, electrical, gravitational, and seismic. Each class depends on the existence of a definite property in which the valuable mineral to be discovered differs materially from the surrounding rocks. In the four classes, the property will be, respectively, magnetic permeability, electrical conductivity, density, and elasticity. By far the largest differences occur in the case of electrical conductivity, where it is not rare to find ratios of the order of several millions, or even billions, between ores, sulphide ores especially, and the surrounding rock. Hence the sensitiveness and delicacy of electrical methods. Of these four classes, only two, the electrical and the magnetic methods, have been put to extensive practical use in the discovery of metallic ores. The other two classes are important mainly in connection with oil detection.

Jan 1, 1928

By P J. Marsh, P J. Bartsch, N J. Semler

Iron Road Limited is currently studying the feasibility of producing 20 Mt/a of high-grade (67 per cent Fe) magnetite concentrate from a 2.6 Bt resource (JORC) located at Warramboo on the central Eyre Peninsula in South Australia. Bulk concentrate has been tested at a relatively coarse grind size of -106 ¦m. The preliminary flow sheet has been confirmed based on initial mine plans and comprehensive metallurgical testing across the range of mineralisation. Extensive Davis tube testing to predict magnetite recoveries has been conducted over the resource, however this was completed at settings different to the optimised settings developed in the metallurgical test work program.This paper outlines the development of an ore treatment simulation in SysCAD which utilises the mine production plan, the Davis tube test data from the resource, data from metallurgical test work and process design criteria to predict magnetite concentrate deliveries. Mineralogical data, including QEMScan results and metallurgical assessments, were a fundamental basis of the process models which enable predictions of concentrate yield and quality. Power and water requirements are also calculated within the model. SysCAD dynamic simulation has been used to assist with the design of the process plant and downstream infrastructure. The simulation has been set-up to allow iterative integration and optimisation of the mine plan when it becomes available.CITATION:Semler, N J, Marsh, P J and Bartsch, P J, 2013. Iron RoadÆs prediction of magnetite concentrate production from the Central Eyre Iron Project, in Proceedings Iron Ore 2013 , pp 539-546 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By P Lindsay

A numerical model has been developed to simulate the effectiveness and costs of a number of conceptual remedial measures aimed at reducing acidity and metal concentrations in the Ngakawau River and its tributaries near the Stockton Coal Mine, situated on the West Coast of New Zealand. The Stockton Coal Mine has been in operation over the past 100 years. During that time, seepage from waste rock dumps has contributed to elevated acidity and metal concentrations in the Ngakawau River and some of its tributaries. The yearly mean rainfall at the mine site is 6000 mm. The model, developed using GoldSim software, simulates rainfall, run-off and stream discharge for 26 tributaries. It then calculates acidity and metal concentrations in the mine impacted tributaries and the dilution downstream from the mine. The model has been calibrated to measured flow and acidity and metal concentrations in the Ngakawau River and some of its tributaries. Acidity and metal loads are removed from the system in accordance with specified efficiencies and capacities of the respective conceptual remedial measures. The user can compare specific remedial measures, or a combination of conceptual remedial measures. The model predicts the acidity and metal concentrations at a number of monitoring stations for any remedial strategy selected by the user. It also calculates the capital and operational costs for that particular remedial strategy. This paper presents the development of the numerical model and describes how the end-user can use it to compare the efficiency and costs of various remedial strategies by running different æwhat ifÆ scenarios.

Jan 1, 2006

By S. Banisi

Thickening is the most widely applied dewatering technique in mineral processing. Thickeners are used to increase the concentration of suspension by sedimentation, accompanied by the formation of a clear liquid. As the particles get finer the thickening process encounters difficulty due to a significant change in the settling behaviour of particles. The batch settling tests of coal refuse of a coal washing plant which contained 91% particles smaller than 38µm and 0.6% coarser than 75 µm showed that the optimum feed percent solids that provided highest flux (solids handling capacity) was 4%. The flux of the pulp with the plant solids concentration (i.e., 10%) was 60% lower than that of the pulp with 4% solids. A thickener with a diameter of 22m based on the dilution of feed from solids concentration of 10% to 4% was designed. Monitoring of the thickener performance for a period of one month in the plant indicated that on average the feedrate of 25t/h (dry solids) with solids concentration of 10% could be thickened to the underflow concentration of 26.5% with a clear water overflow. It was found that the key component of the successful operation of the thickener is the dilution of the feed without which the overflow loses its clarity and the system ceases to operate under predetermined conditions. Specially designed feeding system which efficiently dissipated the energy of the incoming flow and staged flocculant addition regime are among the main contributing factors in making the design and operation of such thickener possible.

Jan 1, 2014

By G. E. Peacock

SIGMA MINES is situated in the township of Bourlamaque, Abitibi County, Quebec. It is a gold producer, and presently treats an average of 1,200 tons of ore per day, at a grade of approximately 0.18 oz. per ton recovered. The mill started operations in March, I937, at a rate of 300 tons per day. This was increased to 800 tons in I940, and to 1,000 tons by I943. The rate was cut back during the war years, but was brought back up to capacity by I948. The mill tonnage was in-creased to the present 1,200 tons per day in I960. The underground workings are serviced through No. 2 Shaft (Figure 1), which, with 24 operating levels, extends from surface to a depth of 3,317 feet. When depth exploration was decided upon, two possibilities were considered: (a) deepen the main shaft by1,000 feet; (b) put down a winze for the same distance.

Jan 1, 1962

By George A. Miller

ALTHOUGH the Andean mountain belt, which contains almost all the metal deposits of the other South American nations, does not enter Brazil, this country is rich in mineral resources, for in area it accounts for half the continent and geologically it contains almost all of the Brazilian Shield. This great mass of ancient rocks has been relatively stable for a long time and forms a great area of plateaus and highlands interrupted only by the syncline which carries the Amazon River across it to the sea. Lowland Brazil - the great flood plains of the Amazon. Tocantins, Paraguay, and Parana Rivers-is of no interest to the miner, and in fact supports but a small proportion of the country's population. The highland area is divided into unequal parts by the Amazon River; the north half is underlain by the north lobe of the Brazilian Shield which extends into Venezuela as far as the Orinoco, and into the Guianas, and is known as the Guiana Highlands. Mineralization appears to have been weak in the Brazilian portion of these hills. In fact most of the ore deposits are to be found in the States of Minas Gerais and Bahia, although the neighboring states of Sao Paulo, Pernambuco, and Piauhy can also boast of some deposits. Goias and Matto Grosso are as yet incompletely prospected but are considered to contain reserves for the future.

Jan 1, 1945

By George A. Miller

AMERICANS like engines, but more than anything they like powerful engines, and next to that they want them quiet, silent, smooth; perhaps a slight purr might be permitted, but they must not knock. To provide a gasoline to fit all these requirements, American petroleum technologists have experimented for years, and mounting octane numbers of the gasolines the refiners have produced both before and during the war bear witness to their success. The question on everyone's mind now is what may we expect in the way of engine fuel in the postwar period? The gasoline drouth during the war rationing, the inconvenience of doing without a car were major annoyances to all motorists, but they put up with them pretty cheerfully for the most part. However, now that the war is over, and the jalopies are all out and the better cars have been taken off the jacks and brought out on the road, the call is for "Some of that good gas-fill her up, if you please."

Jan 1, 1945

By George Mixter

MINING, in contrast to manufacturing, deals with a wasting asset. That which is taken out of the ground is gone, the property is depleted to that extent, and will eventually become exhausted of profitable ore. So the life of a mining company is dependent upon the ability of its management to develop improved methods to permit extraction at a profit of the lower-grade ores which remain, to extend by intelligent exploration the limits of its known ore bodies, and to find and acquire new properties to take the place of those that, for one reason or another, are no longer operated. Its history is a story of constant change, of the working out of properties here and the acquisition and development of properties there, to maintain the vitality of the whole. It is a story of estimating with the tools and the knowledge available the location and extent of hidden ore bodies and of devising the means of extracting

Jan 1, 1948

By Douglas R. Schmitt

In general, knowledge of the state of stress within the Antarctic lithosphere remains largely unconstrained due in part to Antarctica?s inaccessibility and because of the paucity of seismic focal mechanism solutions. As such, an important component of the ANDRILL project was to acquire new information on the stress directions and magnitudes within the upper crust. Extensive fracture mapping of the core and oriented ultrasonic televiewer logging were carried out to provide strong constraints on both stress orientations and the faulting regime. The first hydraulic fracturing stress determinations in Antarctica were also carried out to provide complimentary stress magnitudes. These measurements were accomplished using a wire-line transported hydraulic fracturing system consisting, essentially, of two synthetic polymer packers that were inflated to isolate the 1-m long pressurization interval. The tests were conducted at the end of the drilling and logging in a ~130-m section specially drilled below 1000 mbsf (nearly 1500 m from the rig floor) for hydraulic fractures. This zone was drilled primarily through competent, dense, and low permeability diamicts. The core fracture and televiewer logging information was used to site twenty separate measurements. Classic hydraulic fracturing pressurization records with unambiguous breakdown and fracture closure pressures were obtained in about half of the measurements. The remaining tests provided fracture propagation and closure pressures that are consistent with the classic breakdown curves, but they did not include a clear breakdown pressure and are indicative of the reopening of either natural or drilling induced fractures in the wellbore wall. The preliminary analysis of the results are in generally good agreement with the stress directions indicated by the core fracture logging and the stress regime suggested by the character of the drilling induced core fractures.

Jun 1, 2012

By Thomas J. Peters

A mineral survey of the Sill Hill RARE II area (No. 5304), covering 5,200 acres (2,100 ha) of the Cleveland National Forest, San Diego County, California, was conducted by the U.S. Bureau of Mines and the U.S. Geological Survey. This survey was in conformance with the Resource Planning Act (RPA) of 1974, as amended by the National Forest Management Act of 1976, to provide mineral resource information for study area classification. Bureau of Mines personnel made an economic appraisal of mineral deposits by searching pertinent geological and mining publications as well as U.S. Bureau of Land Management, U.S. Forest Service, and U.S. Bureau of Mines files and records. Known mines, prospects, and mineralized localities were examined during 1981, and sampling and mapping were done where warranted. The Geological Survey 'did geologic mapping, geochemical sampling, and geophysical surveys to aid this study.

Jan 1, 1983

By K. C. Dunham, M. Solomon, T. A. Rafter

Sulphur isotope ratios have been determined for 81 sulphides and S and O isotope ratios for 26 barites from the Alston Block in the northern Pennine ore field. In addition, both isotope ratios have been determined for 29 evaporitic anhydrites of various ages from European and Australian localities. The consistency of the sulphate isotope ratios over a wide area of the northern Pennines, and their similarity to values for Lower Carboniferous evaporites, suggests that the sulphate originated from Lower Carboniferous connate waters. It is suggested that these mingled with warm brines rising through granitic plutons beneath Tynehead and Upper Weardale, the aqueous sulphide ion in these brines having a delta34S value of approximately +10 per mille. The delta34S values for the sulphides range from +15.0 to -5.9 per mille and show an outward zoning with higher values in the central fluorite zones and mainly negative values in the outer barite zones. The wide range of delta34S values for the sulphide S is not characteristic of magmatic S and there is no adequate local source in the Carboniferous sediments. It is suggested that formation waters, probably mainly of connate origin, sank down sufficiently deep to become heated above 200°C before rising through Caledonian granite plutons into the Carboniferous sediments, where they spread laterally to mingle with cooler sulphatic connate water. The rising fluids were hypersaline brines carrying F, Ba, Pb, Zn, Cu and S. Temperatures of deposition calculated from galena-sphalerite isotope fractionation are similar to temperatures previously determined from fluid inclusion studies.

Dec 1, 1971

By J. Jankovic

Numerous advantages have been recognized for solid oxide fuel cells (SOFCs) operating at temperatures of 500-700°C. However, there are several issues related to low temperature SOFCs, such as high electrolyte resistance and high electrode polarization. One of the routes to enhance the electrode performance, particularly for the cathode, is to use new materials with optimized microstructure. In this work, the plasma-spraying technique, recognized to have several advantages over presently used deposition techniques, was used to deposit cathode materials onto ceramic and stainless steel substrates to obtain highly porous structures. Cathode materials with composition of Lao 6Sr0.4Co02Fe0 8O3 (LSCF) were employed in the powder form. The LSCF was prepared from powder precursors with different pore formers and binder levels, or from already produced, single-phase LSCF. The (La0.8Sr0.2)0.98MnO3 (LSM) cathode material was also processed for comparison purposes. The deposition process was developed to obtain coatings with good bond strength, porosity, film thickness and residual stresses. The phase and microstructure of deposited materials were characterized using XRD and SEM.

Jan 1, 2005

LIST OF THE MEETINGS OF THE INSTITUTE AND THEIR LOCALITIES FROM ITS ORGANIZATION Transactions Number Place Date Vol Page 1 Wilkes-Barre, Pa May, ?71 1 3 2 Bethlehem, Pa August, ?71 1 10 3 Troy, N Y November, ?71 1 13 4 Philadelphia, Pa February, ?72 1 17 5 New York, N Y May, ?72 1 20 6 Pittsburg, Pa October, ?72 1 25 7 Boston, Mass February, ?73 1 28 8 Philadelphia, Pa May, ?73 2 3 9 Easton, Pa October, ?73 2 7 10 New York, N Y February, ?74 211 11 St Louis, Mo May, ?74 3 3 12 Hazleton, Pa October, ?74 3 8 13 New Haven, Conn February, ?75 3 15 14 Dover, N J May, ?75 4 3 15 Cleveland, 0 October, ?75 4 9 16 Washington, D C February, ?76 4 18 17 Philadelphia, Pat June, ?76, 5 3 18 Philadelphia, Pa October, ?76 5 9 19 New York, N Y February, ?77 5 27 20 Wilkes-Barre, Pa May, ?77 6 3 21 Amenia, N Y October, ?77 6 10 22 Philadelphia, Pa. May, ?78 6 18 23 Chattanooga, Tenn May ?78 7 3 24 Lake George, N.Y. Oct. ?78 7 25 Baltimore, Md. Feb. ?79 7 26 Pittsburgh Pa, May ?79 8 27 Montreal, Canada Sept, ?79 8 28 New York, N.Y. Feb, ?80 9 29 Lake Superior, Mich Aug, ?80 9 30 Philadelphia, Pa. Feb, 81 9 31 Staunton, Va May, 81 10 32 Harrisburg, Pa Feb, 81 10

Jan 1, 1952

(Under this heading will be published notes sent to the Secretary of, the Institute by members or other persons introduced by members.) Development and production. Member open for engagement. Past year in war mineral field work, operation and production. Ten years' thorough experience in both subordinate and executive positions, gold, silver and copper in the United States, Mexico, and South America. Age 37, married. Minimum salary $3600. Interview. South or East. A-577. Engineer and executive. Captain U. S. Army, age 36, expects discharge before July 1. Seven years' mining and metallurgical experience. Six years with large technical college as assistant professor of mining and directing extensive experimental work. Desires position as executive or research engineer with reliable company or as professor of mining with first-class college. A-909. Mining engineer. Twenty-five years' experience including mine and works operation, construction, plant installation, and mine examination. Speaks Spanish. A-1173. Metallurgical engineer. Twelve years' laboratory and operating experience, covering copper blast furnace, roasting, reverberatory smelting and latest Cottrell treater practice on copper dust and zinc dust. Technical graduate. 36 years of age, married. Highest recommendations. Open for immediate engagement. A-2354. Mining engineer. Junior Associate. At liberty about July 1. Captain Heavy Artillery. Single, age 24. Go anywhere. Best refer-ences. A-2843. Engineer. Age 26, single, graduate Missouri School of Mines, B. S. in Mis. Met. E. Desires position with oil or metal company in any capacity. Location immaterial. At present engaged, desires change. A-2844.

Jan 7, 1919

By P. M. Lin

This paper presents an overall stabilization method to eliminate the potential of reoccurrence of subsidence over abandoned mine lands. The method considers column grouting at the specific locations inside the subsidence influence areas including the distressed and stress concentration zones instead of grouting' around and beneath the damaged structures. The later method is commonly used for AML subsidence abatement at the present. By using finite element method the conditions of stress distribution in the strata before and after grouting can be calculated. The design of grout pattern includes the location and number of the grouting holes. Based on the calculation, the proposed method significantly reduces the stress concentration, i.e., the potential of reoccurrence of subsidence can be reduced or eliminated. A comparative analysis including number of grouting holes, grout affected area, stress level, and potential of subsidence reoccurrence will also be presented.

Jan 1, 1990

By A Crosky, S Saydam, H Chen, H L. Ramandi

Cable bolts and rock bolts are used as primary and secondary anchoring systems in many underground mines. Reports on the premature failure of cable bolts and rock bolts due to stress corrosion cracking (SCC) in underground coalmines have been increasing in the past two decades. The previous studies found that the SCC in both rock bolts and cable bolts occur as a consequence of atomic hydrogen diffusion into the material, which is known as hydrogen-induced stress corrosion cracking, HISCC (Craig et al, 2016; Wu et al, 2018b). While research to understand the process of SCC occurrence in underground mines is still required, finding a prevention solution to protect the bolts from HISCC is crucial. In this study, we analyse a variety of commercially available coatings for steel corrosion prevention, including barrier coating (ie epoxy, polyester TGIC) and sacrificial coating (hot-dip galvanising). We test the coating on coupons manufactured from rock bolts and cable bolts used in the coal mining industry.

Nov 29, 2022

By J. P. Harrison, R. Roostaei

"In this paper we investigate the consequences of using conventional triaxial peak strength criteria in the polyaxial stress conditions that occur around the end of a long circular underground opening. A series of 3d boundary element analyses were performed using Examine3D to determine the stresses induced around the tunnel in different in-situ stress conditions. To discuss the applicability of a triaxial strength criterion in failure prediction, strength factors were computed for both the Ottosen polyaxial strength criterion and the triaxial Hoek-Brown criterion. Assuming that the Ottosen criterion is an accurate indicator of strength factor, the discrepancy from this value due to the Hoek-Brown criterion is the error in prediction.In order to simultaneously show the error in prediction and actual strength factor, a quantitative bivariate colour scheme is used to visualize the results. This allows rapid identification of regions with large error, and where either unsafe or overly conservative conditions occur. We show how the inappropriate use of triaxial criteria rather than polyaxial criteria leads to an under- or over-estimation of strength factor, and can result in uneconomic or unsafe design. Extending the analysis to different in situ stress regimes shows how the in situ stress conditions affect the assessment."

Jan 1, 2015