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By Wayne A. Van Voast

Many coal beds that will be mined in southeastern Montana are aquifers that provide essential local water supplies. Mine cuts along aquifer outcrops create almost imperceptible piezometric changes. Monitoring near such operations at Colstrip has detected almost no water-level declines in observation wells. Mine cuts between outcrops induce rapid storage depletion and associated piezometric depressions. One such cut near Decker induced 1,250 m3/day of flow from storage and created a piezometric depression of 3 meters or more as far as 1,500 meters from the mine. No wells have yet become non-productive but losses of some are inevitable as operations expand. Alternative supplies are available from aquifers stratigraphically below the disturbed materials. Effluents from active mines are chemically similar to other area waters because they are mixtures or ground waters entering the mine cuts. Occasional high concentrations of nitrate do occur, however, as residuals from explosives. Spoils generally consist of confined aquifers of wasted coal and coarse rubble at their bases, overlain by finer-grained sand, silt, and clay. Hydraulic conductivities and storage coefficients are comparable with those of undisturbed confined aquifers. Water quality in mined lands is highly diverse because of diverse spoils lithologies and poorly-established ground-water circulation. Ground water in spoils is more mineralized than in the coal beds and chemically resembles waters from sandstone aquifers. Hydrologic effects of mining will not be catastrophic or widespread but may have local significance. Most notable changes will be in water quality; availability will not be permanently reduced.

Jan 1, 1978

By Fathi Habashi

Extraction by organic solvents is a chemical process in which metal species in the aqueous phase react with an organic reagent to form an organometallic com- plex, thus, the metal species leave the aqueous phase and enter the organic phase from which it can be stripped back in the aqueous phase to obtain a pure and a concentrated solution. The metal in the organic phase is not bound to carbon atoms as in organometallic compounds but to oxygen, nitrogen, sulphur, or hydrogen by a co-ordination (dative) bond (Habashi, 1999).Solvent extraction was used for the first time in hydrometallurgy in connec- tion with the special and urgent materials requirements of nuclear energy during World War II. A plant was constructed in the United States for the preparation of high-purity uranyl nitrate solution. In this plant, the yellow cake (a high-grade sodium or ammonium uranate) was dis- solved in HNO,, and uranium was selec- tively extracted by ether then stripped by water to give a concentrated solution of pure uranyl nitrate. This was gradually followed by developing methods for other high-priced metals such as plutonium, thorium, niobium, tantalum, zirconium, hafnium, boron, beryllium, and molybde num. The second step took place in the 1960s when solvent extraction was applied for the first time to extract a rela- tively cheap metal-copper. At present, solvent extraction technology is wide- spread, well accepted, and highly efficient. Solvent extraction had its origin in the discovery, by Christian Friedrich Bucholz (1770-1818) in 1805, that uranyl

Sep 1, 1999

By AKIHIRO YOSHIMURA, HIDEKAZU KATO, KOTA TAKATORI, YASUNARI MATSUNO

Chalcopyrite (CuFeS2) is the most refractory copper mineral when treated in conventional sulfate media leaching systems. This study is the first to examine the use of a dimethyl sulfoxide (CH3SOCH3), or DMSO, solution containing copper chloride (CuCl2) in the leaching of chalcopyrite. The DMSO solution containing CuCl2 could selectively dissolve the valuable metals of copper (Cu) and gold (Au) from chalcopyrite while leaving minerals with little economic value, such as pyrite (FeS2), and the penalty element arsenic (As) in the residues. Leaching chalcopyrite using a DMSO solution that contains CuCl2 offers a number of advantages, including eco-friendliness and easy operation.

By P. Wittke-Gatterman

ABSTRACT: A three dimensional constitutive law for swelling rock is presented. It can be applied to the osmotic swelling of mudstone as well as to the swelling of rocks containing anhydrite. It describes the development of time-dependent strains and stresses due to swelling considering elastic and viskoplastic behaviour. Furthermore an anisotropic swelling behaviour can be considered. This constitutive model was implemented within a numerical computation program according to the finite element method and calibrated on the basis of the results of measurements in the investigation drift of the Freudenstein tunnel which is completely located in the unleached Gypsum Keuper. A parameter combination could be found which results in a good agreement between numerical solutions and results of measurements. Therewith an analysis procedure which enables the design of tunnels in swelling rock is available. ZUSAMMENFASSUNG: Im vorliegenden Beitrag wird ein dreidimensionales Quellgesetz vorgestellt, das nach derzeitigem Kenntnisstand sowohl auf das osmotische Quellen von Tonsteinen als auch auf das Quellen anhydrithaltiger Ton- beziehungsweise Schluffsteine anwendbar ist. Das Stoffgesetz wurde in ein Finite-Elemente-Programm implementiert und anhand von Meßergebnissen des im unausgelaugten Gipskeuper liegenden Untersuchungsstollens des Freudensteintunnels kalibriert. Es ist gelungen, eine Kennwertkombination zu finden, mit der alle Meßergebnisse gut beschrieben werden können. Damit steht ein Bemessungsverfahren für Tunnel in quellfähigem Gebirge zur Verfügung. RÉSUMÉ: Dans l'article présent un loi de gonflement à trois dimensions est présenté, qui peut être appliqué aussi bien au gonflement osmotique de l'argile compactée q'au gonflement de l'argile compactée ou du limon compacté contenant de l'anhydrite. Le loi de comportement était implémenté dans un programme numérique d'éléments finis et calibré avec des résultats de mesures de la galerie de recherche du tunnel de Freudenstein, situé dans le Keuper de gypse non lessivé. On est réussi à trouver une combinaison de paramètres avec laquelle tous les résultats de mesures peuvent être bien décrits. Par ce moyen, une méthode de dimensionnement existe pour des tunnels dans de la roche capable de gonfler.

Jan 1, 2003

By J. A. Kosek

Work has been carried out under Bureau of Mines Contract HO 395132 to develop improved sensor cells for use in direct-reading detectors and diffusion exposure meters. A pumped CO sensor cell was developed which has a shorter response time, improved temperature cycle characteristics, and improved linearity and stability at high CO concentrations. Diffusion CO sensor cells have shown good response level stability and linearity up to 1000 ppm. In addition, a new sensor cell catalyst has been developed for NO2 sensor cells which has a much shorter response time and improved response stability characteristics.

Jan 1, 1982

By Thomas Domanski

Any type of deep excavation whether for Bored Piling, Diaphragm Walls or Contiguous Bored Piling Walls depends on forming a stable borehole with a defined cross-section to receive safely the permanent materials. In modern construction the excavation depth can reach well the range of 100 m and above. The diameters of the Piles reach often sizes of 2.5 m and bigger. Top casings in Bored Piles (Diaphragm Wall none) are rather short and stability below the casing, need to be secured by stabilization slurry. The boreholes need to be formed through a variety of different materials and stand open for an extended period. Without a safe stable borehole, it is impossible to produce quality products and work cost-efficient. The understanding and proper usage of a suitable slurry is a key element essential for the delivery of Foundation Elements with high quality and within a reasonable budget. The setting of mechanical and rheological parameters in specifications is necessary and helpful, but probably insufficient to embrace and control such a key element in the practical implementation of foundation construction. The proper selection, design, implementation and supervision of slurries on site requires both from Contractors and Engineers to understand how different slurries do function. Only with this knowledge the right decisions in slurry operations can be made. This talk is directed to give some help to both, Contractor’s and Engineer’s, in understanding how different type of slurries do work. (Which ones should be preferred in what kind of soils.) The better knowledge will help the Contractor to control cost and enhance production. The Engineer will be able to assist in arriving at the appropriate technical choices and include in the specifications.

Sep 1, 2022

By Richard L. Ashbrook, John F. Wallace

Several high-temperature eutectics of cobalt and nickel alloys were modified by small additions of selected elements. Thes-e alloys were compared to unmodified melts for microstructural variations. A few modified compositions were selected on the basis of structure and their tensile and stress-rupture behavior determined. The results of stress-rupture tests in air at 1800 F and room-temperature tensile tests of four high-temperature eutectics showed modification capable of producing substantial improvements in properties. The microstructures were altered and mechanical properties improved by: a.) dispersing a subordinate phase more uniformly throughout the matrix; b) replacing large continuous -network or platelike constituents with small equiaxed discontinuous phases; and c) by forming new, finely divided phases. tHE term "modification" is most commonly used to describe the refinement in microstructure of the Al-Si eutectic that occurs as a result of rapid cooling from the melt or on slow cooling after treatment with small amounts of sodium.1 "Modification" has also been used to describe the change from flake to spheroidal graphite in the austenite-graphite eutectic of cast iron.2 This change of graphite shape is accomplished by small additions of cerium or magnesium.3 Other systems have also been shown to be capable of modification, for example: Pb-Sn by copper;4 Al-Cu by sodium;5 Al-Mn by sodium;5 and Pb-Sb by aluminum.5 Although modification of Al-Si alloys and cast irons is usually accompanied by improved mechanical properties, a general definition of modification has been suggested to include the effect of small quantities of impurity elements on the microstructures of all eutectic alloys, regardless of the effect on the mechanical properties.6 In this paper, the term "modification" is employed in a broad sense to include the formation of third phases or even the supplanting of one of the binary eutectic phases by a third phase. The mechanism of modification, as for any solidification phenomenon, must be considered primarily in terms of nucleation and growth. Although both nuclea-tion and growth mechanisms are required to explain all the phenomena observed in connection with the solidification of modified eutectics, various investigators have usually favored one or the other.7"16 It has been shown that modification of a binary eutectic can be effected by addition of a solute element that has greatly different distribution coefficients or k values in the two phases of the eutectic. Under these conditions, differences in the temperatures at the solid-liquid interfaces of the two phases retard the growth of one phase with respect to the other.4 It has also been shown that increased undercooling favors a transition from a rodlike eutectic to a globular eutectic.17 A mechanism proposed for the transition from lamellar to rodlike eutectics depends on the concept of constitutional super cooling.18 The modification of eutectic alloys may be of interest for high-temperature service as well as at room temperature. Although "high-temperature eutectic alloys" may appear to be a contradiction in terms, many eutectic systems, including those studied in this work, have melting points in excess of 2400°F. One of the mechanisms by which high-temperature alloys are strengthened is dispersion of a relatively brittle phase such as an oxide, carbide, or an inter-metallic compound throughout a ductile matrix. For a given volume fraction of dispersed phase, strength is increased by decreasing the size and spacing of the dispersed particles.19'20 Furthermore, room-temperature ductility may also be increased by changing the shape of a brittle dispersed phase from platelike to equiaxed or spheroidal.8 Overaging and redissolving of the secondary phase limit the maximum temperature to which precipitation-hardened alloys can be used. However, in a binary eutectic system, both phases coexist up to the melting point. Although all eutectic structures are not completely stable,21 a dispersion-hardened cast high-temperature alloy might result if a fine distribution of one of the eutectic phases could be obtained during solidification. An additional reason for interest in eutectic alloys is their excellent castability.22 Since eutectic alloys, like pure metals, freeze at a single temperature rather than over a range of temperatures, their castability is superior to solid-solution alloys with long liquidus to solidus ranges. The purpose of this research was to study the effects of small solute additions on the microstructure and mechanical properties of a number of high-melting-point eutectic compositions.

Jan 1, 1967

By Harold Price

ONE year ago, that is in January, 1923, there had not been constructed a single oil-storage tank of 55,000-bbl. or more capacity with a completely electric welded roof and bottom. Today, there are at least fifty 80,000-bbl. storage tanks completed, or nearing completion, on which both the roofs and the bottoms are electric welded. It is the purpose of this paper to describe, in a general way, the construction of these FIG. 1.-ELECTRIC-WELDED SEAMS AND RIVETS OF BOTTOM IN 55,000-BBL. TANK AT EL DORADO, KANS., SHOWING ALSO PATCH PLATE WELDED TO BOTTOM. welded roofs and bottoms, and to give their advantages over riveted construction. All of the following data and conclusions were obtained from observations made during the welding of tanks by the Welding Engineering Co. at Texas City, Tex., and Tonkawa and Burbank, Okla. As far as can be determined, the first electric welding on large tankage was completed in May, 1922. At that time the Empire Companies of Bartlesville, Okla., discovered a badly leaking bottom in a 55,000-bbl. tank at El Dorado, Kans. They had considered concreting this bottom, but because of the much smaller cost, decided to try electric welding; so a- contract was given the Welding Engineering Co. of Bartlesville, Okla. In this instance, no new sheets were added, the bottom being repaired by electric welding of all seams and rivets, Fig. 1. In some places where the original rivets were missing, the holes were filled by welding; patch plates were also added at certain badly worn spots. This tank has since been in service over a year and half, but no other

Jan 6, 1924

By I. L. Nichols, K. C. Dean, P. H. Johnson

Hydrochloric acid , sulfuric acid , and chloridizing roast- water leaching methods for dissolution of cesium and rubidium from Maine , Canada , and Southern Rhodesia pollucite ores and their flotation products were investigated by small- scale tests . Optimum conditions were determined to be ( 1 ) for hydrochloric acid leaching , use 12.7 equivalents of 8.8 normal acid per equivalent of cesium in the sample and leach for 6 hours at 100 ° C ; ( 2 ) for sulfuric acid leaching , use 12.7 equivalents of 14.4 normal acid and leach for 2 hours at 120° C ; and (3 ) for chloridizing roast - water leaching , roast minus 200 - mesh ore, limestone , and calcium chloride in a ratio of 2 : 4 : 1 , respectively , for 1 hour at 900 ° C , and leach the calcine for 1 hour at 80 ° C with enough water to give 35 pct solids . Extractions of cesium from ores and flotation products containing over 20 pct cesium were in excess of 97 , 93 , and 96 pct for the hydrochloric acid , sulfuric acid , and chloridizing roast - water leach processes , respectively .

Jan 1, 1964

By R. W. Raymond

ALEXANDER BRINTON COXE was born in Philadelphia, Pa., Jan. 19, 1838, the second of five sons of lion. Charles Sidney Core and Ann Maria Brinton. A more extended history of his family and its important relations to the development of the United States will be found in my Biographical Notice of his younger brother, Eckley B. Coxe, published in 1895. It is therefore sufficient to say here that Dr. Daniel Coxe, a distinguished physician and surgeon of London, and a medical attendant of Charles II and Queen Anne, purchased, in 1684 and 1686, lands in East and West Jersey from grantees of the Duke of York, and became Governor of West Jersey, in which capacity he did much to develop the provincial fisheries, the manufacture of marine salt and pottery, the exportation of tim¬ber and the West India trade. In 1698, having acquired the royal patent of the Province of " Carolana," covering (with some reservations) the territory extending from the Atlantic to the Pacific, between the 31st and 36th parallels of N. latitude, Gov. Cole sent an expedition from Charleston, S. C., to the Mississippi. In 1769, seventy years later, his grandchildren surrendered to the Crown their title under this vast and vague patent, receiving in return a grant of 100,000 acres in the Colony of New York. The line of his descendants, so far as they concern this sketch, is as follows 1. Col. Daniel Core, his son, b. 1673, who came to New Jersey in 1700; resided there until his death (1730); held many high offices; and issued in London (1722) A Description of the Provinces of Carolana, containing probably the earliest published plan of political union for the British Colonies in North America.

Sep 1, 1906

By W. Hrynewich

"The Central Canada Potash facility, a division of Noranda Metal Industries Limited, is located 3 kilometres south of the junction of Highways 16 and 2, about 75 kilometres south-east of Saskatoon, Saskatchewan. The site occupies 26~ hectares of land and includes well-equipped machine and electrical _shops, a 325,000-tonne muriate storage and reclaim warehouse, a stores warehouse, processing plant (mill), two mine shafts (one for production, the other for servicing and personnel transport), as well as a two track product loading complex. Access to the site is by road and railway (CN and CP Rail). Suppliers of operating and maintenance use both means of transportation, whereas muriate shipments are entirely by railway.Currently five continuous mining machines - one a Goodman 526 borer and four Marietta 911-A units produce some 10,500 tonnes of ore per operating day. A smaller Voest-Alpine Af.1-100 boom type miner is used for floor cutting which was previously done by a production unit. In order to maintain safe, competent ground conditions only 35 percent of the total ore is extracted. At this rate mine reserves are deemed adequate for about 100 years. The plant has operated since August 1969 and has a current practical annual capacity of 1,270,000 tonnes of muriate. As of June 30, 1981, some 11.9 million tonnes of muriate had been produced from 31.4 million tonnes of ore. Of the total muriate, 6.1 million tonnes was granular, 4.8 million was coarse, and 1.0 million was standard. No standard product has been made since August 1978."

Jan 1, 1982

By Derek du Preez, Andrew Hall, Timothy M. Pelech

Net Present Value (NPV) derived from Discounted Cash Flow (DCF) analysis remains the dominant metric for evaluating mining projects despite its well-documented inability to capture managerial flexibility under uncertainty. DCF assumes that all risks are perfectly priced by financial markets. This is an unlikely assumption for volatile commodity prices, geological variability, or the array of mining technical and operational risks present on all mine sites. Real Options Analysis (ROA) was developed to remedy this limitation by explicitly valuing the ability of managers to defer, expand, scale, switch, or abandon investments as new information emerges, and to capture upside and mitigate downside risks. While ROA is philosophically correct and routinely shows an uplift in project value compared with DCF, its practical application at industrial scale is severely constrained, ROA faces the reality of a combinatorial explosion in complexity of decision trees, Monte Carlo simulations and other models required when multiple interdependent or sequential options exist across numerous mining zones and time periods. The AMC Hill of Value® (HoV) process adopts the same intellectual foundation as ROA, that flexibility has economic value, but operationalizes it through a far more robust and scalable architecture. It is built on parametric relationships, rapid scheduling, and multi-objective evolutionary optimisation. HoV can evaluate millions of compound, interdependent real options in a single optimisation run, delivering resilient, adaptive strategies that preserve managerial flexibility while simultaneously optimising NPV, mine life, risk exposure, and other corporate objectives. This paper demonstrates that HoV is the practical, industrial-scale embodiment of real options thinking in mining: it discovers, ranks, and translates the most valuable real options into strategic mine plans, overcoming the scalability barriers that have prevented widespread adoption of classical ROA.

Feb 22, 2026

By N. L. Wimmler

"INTRODUCTION The Southern Cross district in Deer Lodge County, Mont., has been chiefly a gold producer. Most of the production has come from gold-bearing hematite-limonite ores. Some of these ores were mined and shipped to smelters for use as flux in smelting copper ores. A magnetite deposit in the Pomeroy property, containing no gold or other economic nonferrous minerals, was mined from 1921 to 1923, the ore being shipped to smelters for flux.The iron-bearing deposits in the Southern Cross area were examined by Bureau of Nines engineers/ on June 28, 1943, and October 14, 1943. As a result, a Bureau exploration project was recommended; it was conducted during 1944. A magnetometer survey was first made of the magnetite-bearing area at and in the vicinity of the Pomeroy property. Exploration by diamond core drilling was then conducted within this area, and in the Southern Cross and Hold Fast properties. The cyanide tailings dump at the Hold Fast mill was sampled by auger drilling.This report presents the data obtained by the Bureau of Mines exploration."

Dec 1, 1946

"Chairman: Mr W. S. GALLAGHERRapporteur: Professor A. M. STARFIELDPapers:Long-term mine production scheduling by G. C. S. BurneAn application of linear programming to investment analysis by A. ErlandssonOptimizing medium-term operational plans for a group of copper mines by M. Splaine, D. C. Atkinson, W. Davison and L. SmithThe simulation of underground stoping and transport operations in gold mining by F. H. Touwen and N. C. JoughinProduction planning is a subject that lies at the interface between the computing centre and mine management. Discus¬sion during this session was thus largely concerned, directly or indirectly, with communication between computing and mining personnel, and as such was relevant to the symposium as a whole.Mr A. Weiss set the tone of this discussion by referring to `user-orientated systems'. He congratulated Mr Burne in this regard, pointing out that his long-term production scheduling program, as a computer system, was similar in approach to the manual system it replaced, and was therefore easily understood by planning engineers. He asked whether the schedule engineer had his 'hands on' the system, to which Mr Burne replied that the engineer did in fact spend several days running alternative schemes through the computer. Mr Weiss commented on the advantage of having terminals on site for this sort of engineer-computer interaction. He also commented on the flexibility of Mr Burne's approach to scheduling and how preferable this was to a one-step optimization package. This was brought home by a question from Mr H. D. Small: Mr Burne's program sometimes found it necessary to temporarily halt an advancing face, and he asked whether the logic of the program could be altered to avoid this (e.g. by suitably slowing down the rate of face advance). Mr Burne replied that it was in fact easier for the planning engineer to sort this problem out manually. The way in which the computer results were presented made it particularly simple for the production engineer to see how to avoid or remedy a stopped face.On the technical side, both Mr Weiss and Mr H. M. Wells questioned Mr Burne on the handling of grade control by his program. From answers by Mr Burne and his colleague Mr K. H. Thomson it emerged that a spot-check on grade every now and then was all that was necessary at Mufulira, and that the idea of actual grade control was more a question of short-term than of long-term planning."

Jan 1, 2014

By David H. Tang

Massive pillar failures were observed at two underground coal mines. The results of stability analysis using traditional pillar design formulae did not agree with the underground observations. Finite element models were used to analyze the causes and mechanisms of the pillar failures. The results were confirmed by the underground observations. Finally, the improved mine plan for each case was derived to ensure the stability of the underground structure.

Jan 1, 1990

By Ednlund D. North

Discussion of the paper of Edmund D. North, presented at the Spokane meeting, September, 1909, and published in Bulletin No. 37, January, 1910, pp. 21 to 25. A. SCOTT REID, London, Eng. (communication to the Secretary*) :-As a constructor of several glass mine-models, I have read with much interest the description of the model of the Montana-Tonopah mine-workings by Edmund D. North. As an interchange of ideas and experience is always an advantage, and in view of the fact that such models are coming more and more into vogue, perhaps the following remarks on this subject may prove of interest to mining engineers generally and to Mr. North particularly. In the model of the Waihi gold-mine, New Zealand, which I constructed, a dust-proof case is used. The top, bottom, front, and two ends are of glass; the back only is of wood, painted a dull white, against which the mine-workings show very distinctly. Each mine-level is represented by a horizontal sheet of glass, supported on metal runners fixed to the uprights at each end of the case, in a manner similar to that described by Mr. North. The corner uprights are strengthened by having a metal band screwed to the inside face of each, to which the metal runners or supports for the sheets of glass are screwed in turn. The reason for having this additional strength is that as the mine is developed in depth, and fresh levels are opened, the increasing weight of the glass sheets, added to the model, caused the unsupported wooden uprights to bend slightly, so that the glass sheets-did not fit in with the desired nicety, and co-ordination was, to a considerable extent, lost. Strengthening the uprights in this manner is not important in models of mines in which only a few levels have been opened, or when the sheets of glass are small, but in the Waihi model there are 15 sheets of glass to be supported, and more to be added as development proceeds, and the weight is considerable.

May 1, 1910

By D. Parks, A. Miller, M. McNinch, R. Jacksha

Each year, hundreds of mine workers are involved in machinery-related accidents. Many of these accidents involve inadequate or improper use of lockout/tagout (LOTO) procedures. To mitigate the occurrence of these accidents, new safety methods are needed to monitor access to hazardous areas around operating machinery, improve documentation/monitoring of maintenance that requires shutdown of the machinery, and prevent unexpected startup or movement during machine maintenance activities. The National Institute for Occupational Safety and Health (NIOSH) is currently researching the application of Internet of Things (IoT) technologies to provide intelligent machine monitoring as part of a comprehensive LOTO program. This paper introduces NIOSH’s two phase implementation of an IoT-based intelligent machine monitoring system. Phase one is the installation of a proof-of-concept system at a concrete batch plant, while phase two involves scaling up the system to include additional sensors, more detailed safety/performance metrics, proximity detection, and predictive failure analysis.

By I Canbulat, A Mcquillan

This paper presents a parametric analysis showing the impact of virgin in situ stresses on a shallow (less than 100 to 150 m) high slope in a jointed sedimentary rock environment. Slope stability is assessed at varying ratios of slope orientation and horizontal stresses. The results of this study indicate stress conditions should be included in stability assessments of excavated slopes, particularly where structure is orientated perpendicular to the direction of horizontal stress. Some consideration of stress state is applied in deep open cut pits (eg those with planned excavations of 400–1200 m) (Myrvang et al, 1993; Stacey et al, 2003; de Bruyn et al, 2014; Kozyrev et al, 2015). Dodd and Anderson (1972), Kalkani and Piteau (1976), Lee (1978), Coulthard et al (1992), Noorani et al (2011) have studied the effect or horizontal stress and its impact on slope stability, showing that tensile stresses tend to develop at the crest of the slope, with larger tensile zones for higher horizonal stresses and steeper slope angles (Stacey, 1970, 1973; Sjoberg, 2013). However, the consideration of virgin stresses on shallow slope stability is less frequent (Lynch et al, 2005; Dight, 2006; Lucas, 2006; Sjoberg, 2013). This has led many geotechnical engineers to believe the impact of virgin in situ stresses on open cut slope stability is minimal and not worth time or consideration in modelling, or their effects on slope stability are still poorly understood (Stacey et al, 2003; Sjoberg, 2013).

Nov 29, 2022

By Mansoor Barati, Shaghayegh Esfahani

"The slag from extraction of ferrous and non-ferrous metals is a potential heat source which if treated properly can contribute to recovery of a significant amount of energy. The waste heat of slag may be used to generate steam, synthetic fuel gas, or electricity. Although several technologies have been investigated for this purpose, very little has been achieved in terms implementing the technology in industry. In this article, the development and application of various granulation techniques are reviewed and the methods to recover energy from granulated slag are discussed.IntroductionEvery year, more than 422 million tons of slag is being produced around the world as a by-product of the metal manufacturing at temperatures of up to 1300-1600°C [1, 2]. Currently slags are either disposed of or treated by processes such as granulation. Through the granulation process, most slags can be converted into a material which may be fully used as a cement feedstock. Conventional cement production is an energy intensive process with large emissions of CO2; therefore, the replacement can both be energy saving and environmentally friendly. However, for this purpose, the slag should have what is known as a “glassy” content (i.e. it should be amorphous) which requires rapid cooling rates that are not easily achieved due to the very low thermal conductivity. The main challenge in all these processes is to granulate the slag at a high cooling rate while the heat is also being recovered."

Jan 1, 2012

By Robert J. Brennan, Edward R. Navrocky, John W. Buch

In an effort to establish a highly productive mechanized mining system for anthracite beds pitching between 10 ° and 20 ° , for which conventional mobile equipment is not adaptable , the Bureau carried out an experiment in longwall mining using an Anderton- type drum cutter loader and friction - type yielding steel roof supports . The roof- support system proved to be inadequate for breaking the overhanging roof at the break line supports , with the result that the roof broke over the solid coal . The accompanying subsidence destroyed the continuity of the roof in the work area , and the project was discontinued .

Jan 1, 1964