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By Espi J

The Nena high sulphidation deposit, located in the Sandaun Province, PNG, contains a measured and indicated resource of 51 Mt of copper ore grading 0.5% Cu and 0.6 g/t Au at a 0.5% Cu cut-off. The copper orebody is overlain by an 18Mt oxide gold resource grading 0.1 % Cu and 1.4 g/t Au at a 0.6 g/t Au cut-off. The deposit is hosted in advanced argillic altered pyroclastics interstratified with lavas, volcanoclastics, epiclastics and sediments of the Debom Volcanics within the Frieda River Intrusive Complex. Foraminiferal sediments indicate the Debom Volcanics to be Early-Middle Miocene in age. Alteration is elongated along, and concentric about a northwest trending structure (Nena Structural Corridor) which is about 7km in length. The inner two alteration types, residual and massive silica-alunite are strongly brecciated and host the bulk of later hypogene Cu-Au mineralisation. Weakly mineralised weak silica- alunite and barren peripherally zoned clay alteration surround the inner mineralised alterations. The hypogene sulphide deposition was polyphasal, episodic and is zoned from north to south from covellite-enargite ¦ chalcocite (5600N to 5200N) to a mixed enargite-luzonite (5200N to 4700N) to luzonite-stibioluzonite (4700N to 4400N) in the south within a 1200m long by 300m diameter sub horizontal pipe like body. Paragenesis studies indicate that pyrite ¦ marcasite were introduced early with barite and black native sulphur before deposition of banded pyrite (melnicovite) with barite during a period of brecciation. Continued brecciation allowed bladed covellite ¦ chalcocite followed by enargite-luzonite-stibioluzonite ¦ pyrite (brassy) and minor acicular covellite deposition. Yellow native sulphur and trace amounts of galena were deposited in remaining pores. Pre-acid alteration intrusives domed the mainly volcanic stratigraphy in the southwest and post-mineralisation porphyries in the northeast truncate mineralisation. Supergene processes and erosion have modified the top of the deposit, creating a 45m thick goethitic-scoroditic-haematitic gold cap above a 40m thick (on average) chalcocite rich supergene blanket. Lesser amounts of digenite, covellite native copper and rarely seen malachite occur in the supergene copper zone.

Jan 1, 1997

By Hugh M. Roberts

The important place in the economic life of the country that is occupied by the United States Geological Survey and the various state surveys is appreciatcd by most members of our Institute. To the public at large, the functions of these surveys are no doubt largely unknown, and taken for granted. Possibly a realization of the value of the work of these government branches is brought home most fully to that group of our members whose duties as examining engineers and mining geologists take them to mines and prospects in many different parts. The examining engineer or geologist is usually seeking for a judgment on the value of an enterprise from the standpoint of the useful minerals that may or may not be present; he must also attempt some prediction as to future market prices. On his opinion rests the determination of the expenditure of money, which rendered into other language means the expenditure of human effort. An opinion on an exploring venture or the reasoning out of the probable extensions of an orebody requires among many other things a background of knowledge covering the geologic horizons not only of an immediate area but of the surrounding area, a knowledge of the structural geology and of the causes that have operated to form the ores as they are. The great storehouses of this knowledge are the statistics, reports and maps issued by the various geological surveys. They supply the groundwork for additional observations. To these, reference is always made when going into a new district. The technique of work in the field and laboratory, and to some extent the hypotheses that underlie our methods of approach, have been formed by men such as Van Hise, Leith, Kemp, Spurr, Emmons and Lindgren, who developed their powers in the service of the geological surveys. In addition to whatever originality of thought, or power to observe facts and analyze them, may be our portion, we require, in the application of the arts and sciences, a knowledge of what has already been done. We stand on the shoulders of those who have gone before, and the extent of our vision often depends upon the thoroughness with which we form earlier work into one whole and make use of it.

Jan 1, 1935

By Hugh M. Roberts

The important place in the economic life of the country that is occupied by the United States Geological Survey and the various state surveys is appreciatcd by most members of our Institute. To the public at large, the functions of these surveys are no doubt largely unknown, and taken for granted. Possibly a realization of the value of the work of these government branches is brought home most fully to that group of our members whose duties as examining engineers and mining geologists take them to mines and prospects in many different parts. The examining engineer or geologist is usually seeking for a judgment on the value of an enterprise from the standpoint of the useful minerals that may or may not be present; he must also attempt some prediction as to future market prices. On his opinion rests the determination of the expenditure of money, which rendered into other language means the expenditure of human effort. An opinion on an exploring venture or the reasoning out of the probable extensions of an orebody requires among many other things a background of knowledge covering the geologic horizons not only of an immediate area but of the surrounding area, a knowledge of the structural geology and of the causes that have operated to form the ores as they are. The great storehouses of this knowledge are the statistics, reports and maps issued by the various geological surveys. They supply the groundwork for additional observations. To these, reference is always made when going into a new district. The technique of work in the field and laboratory, and to some extent the hypotheses that underlie our methods of approach, have been formed by men such as Van Hise, Leith, Kemp, Spurr, Emmons and Lindgren, who developed their powers in the service of the geological surveys. In addition to whatever originality of thought, or power to observe facts and analyze them, may be our portion, we require, in the application of the arts and sciences, a knowledge of what has already been done. We stand on the shoulders of those who have gone before, and the extent of our vision often depends upon the thoroughness with which we form earlier work into one whole and make use of it.

Jan 1, 1935

By Douglas A. Sloan

Who would believe that young elementary school children could understand something as complex as the mining industry? The Challenge The challenge of accomplishing this is tremendous. An examination of Canadian school children indicated that they knew very little about the world of work in general, and hardly anything about the mineral resource industry in particular. It calls to mind the story about two youngsters who decided to play house. The little girl played her role well as she went about the house doing things she had watched her mother do every day. When it was the little boy's turn, he grabbed his lunch, waved goodbye to his "wife," jumped on his bicycle and pedalled furiously down to the end of the driveway-where he stopped. The youngster explained that he saw his dad go out of the driveway each morning, but he didn't know where he went, or what he did on the job. When you stop to consider the number of families today with two working parents, you can begin to appreciate the importance of the opportunities for role identity provided by this project. The Approach The challenge of teaching the school children of Canada about the world of work and, specifically, the mining industry is the challenge which the Canadian Institute of Mining and Metallurgy met with the Curriculum Development Research project. It started when a small, dedicated group of Vancouver members met Dr. Doreen Binnington. After this meeting, Dr. Binnington, an expert in curriculum development at the University of British Columbia, set herself to develop a curriculum program for the elementary shcools which accomplishes two main goals: It uses the "Identity Approach," developed by Dr. Binnington, an expert in curriculum development at the enable students to understand and appreciate the contribution of people, in this case, working with mineral resources. It has pupils enthusiastically exploring the importance of rocks, minerals, and the mining industry in their lives [(Fig. 1)]. Evolution of the Curriculum Development Research Project When the curriculum development research project was presented to the Vancouver Branch of the Canadian Institute of

Jan 1, 1981

By R. J. Wysor

J. S. UNGER, Pittsburgh, Pa.-On page 22 reference is made to 36 carloads .of dust shipped. Did the material in that last sample come from a; furnace running on pig iron, ferro alloys, or spiegel? R. J. Wysor.-Pig iron; we have not made any ferro alloys; or spiegel at Bethlehem in the last 3 years. J. S. UNGER.-DO you use domestic or foreign ores? R. J. WYSOR.-In regular practice, largely foreign ores. J. S. UNGER.-How much per unit does it cost to produce that? R. J. WYSOR.-You might say it does not cost anything; we do not change our blast-furnace practice at all to obtain the dust. Although it has been a profitable byproduct, I would rather not have it unless we could reclaim it on a large scale, as we would have better working stoves. J. S. UNGER.-Does the trade take it as readily as natural salts? W. J. WYSOR.-The fertilizer dealers have been anxious to get it. This did not happen, however, until the war started. J. S., UNGER.-They have been willing to take anything since the war started. R. J. WYSOR.-Yes. However, we could have sold the material before the war; in fact, about 4 years ago, we had a contract ready to sign, but we did not think it would pay us to bother with it then. W. H. Ross, Washington, D. C.-We of the Fertilizer Division of the Bureau of Soils have been particularly interested in Mr. Wysor's investigations on the possibilities of recovering potash from the blast furnace, and we look upon the results he obtained as among the-most important that have yet appeared on the subject of finding new sources of .American potash. About 5 years ago we undertook a corresponding investigation on the recovery of potash in the cement industry. Representative samples of raw mix and ground clinker were collected from the different cement plants in this country with a view to analyzing each sample for potash. With the data thus obtained and knowing the ratio between the raw mix and the cement produced and the output of the latter, we thought it possible to calculate approximately for each plant the quantity of potash that escapes daily from the kilns. After partly completing the work, however, it had to be abandoned for a time. It was again taken

Jan 4, 1917

By Peter Beardmore, Michael B. Bever

The effects of the temperature of deformation and the degvee of deformation on the annealing spectrum of a Au-Ag alloy have been determined by vesistance measurements. Specimens were deformed in torsion at 4°, 78K and room temperature up to strains nd/l of about 1.0 and were isochronally annealed. Discrete annealing stages similar to those found for pure metals were observed. Stage A occurred below room temperature; the decrease in reszstance associated with this stage increased as the temperature of deformation was lowered or the strain was increased. Stage B manifested itself as an increase in resistance; this is attributed to the restoration of short-range order promoted by vacancy or vacancy aggregate migration. At temperatures above 48S0K, recrystallization or Stage C occurred. Stages A, B, and C in the annealzng curves of this alloy may be considered to correspond to Stages II, Ill, and V, respectively, in the terminology used to describe the annealing spectrum of pure metals. ThE annealing behavior after deformation below room temperature has been thoroughly investigated on pure metals, in particular gold and copper. The occurrence of several discrete stages in the annealing spectrum of these metals has been established, but the interpretation of some of these stages in terms of specific mechanisms is still controversial.' The annealing of alloys deformed below room temperature has been the subject of only a few investigations. In the investigation reported here, a Au-Ag alloy was annealed after deformation at and below room temperature. This continues a research program on the deformation and annealing behavior of Au-Ag alloys.2-8s EXPERIMENTAL PROCEDURE An alloy rod of composition 82.6 wt pct Au-17.4 pct Ag was reduced to wire, 0.0428 in. diam, by swaging and drawing. After a recrystallization treatment, the grain size was 0.031 mm, as obtained from the average linear intercept.7 The ends of wires about 6 in. long were flattened and sealed into short brass tubes with cold setting cement to form the grips of the torsion specimens. The equipment used for deformation has been described elsewhere.6 The specimens were deformed at room temperature, 78", and 4°K to various strains nd/l, where n is the number of turns, d the diameter of the specimen, and 1 its length between grips. The strain rate ?max was 0.1 min-' at the sur- face of the specimen except where noted otherwise. The specimens were annealed isochronally for 30 min at intervals of approximately 30°K from the temperature of deformation to approximately 800°K, except that after deformation at 4°K the lowest annealing temperature was 78°K. A potentiometric method was used to measure the resistance: all measurements were made at 78°K with the exception of some measurements at 4°K mentioned below. Data obtained with a single specimen yielded a complete annealing curve: in several cases duplicate specimens were used to confirm the reproducibility of the curves. Since the surfaces of the specimens were rough after deformation, their diameters could not be measured accurately. The resistance increments after deformation and annealing are therefore reported as percentages of the resistance of the same specimen measured after completion of the annealing, that is, after full recrystallization. The corresponding resistivity values can be calculated by obtaining the effective diameter of a deformed specimen from the ratio of its resistance after recrystallization to the true resistivity, which was determined with a smooth specimen of known dimensions. This method of calculation was used to obtain data shown in several of the figures. RESULTS AND DISCUSSION The isochronal annealing curves after deformation to various strains at 4", 78K, and room temperature are shown in Figs. 1, 2, and 3, respectively. The resistance increment of the as-deformed specimens as a function of strain is shown in Fig. 4. For the specimens deformed at 4°K. values measured at 78°K are plotted with the exception of those for the as-deformed

Jan 1, 1970

By K. Taniguchi, Y. Inada

When underground openings are excavated in rock mass for storage of Liquefied Natural Gas, hereinafter referred to as L.N.G., as its temperature is -162o C, steep temperature gradients and thermal stress occur around the openings. That is, the plastic zone and cracks around openings will expand with time. In this paper, the range of cracks which were obtained by the Crack Analysis Method and the range of the plastic zone which was obtained by the No Tension Analysis Method were investigated and compared.

Jan 1, 1986

By E. S. Davenport, R. J. Hafsten, R. A. Grange

The influence of austenite grain size upon the hardenability of steel is now fairly well understood; for a given austenite, increasing the grain size increases the depth of hardening, and, since the latter is related to the fundamental transformation behavior of austenite, it follows that austenite decomposition must, in general, be retarded by increasing grain size. To date, very little quantitative information bearing directly on the effect of austenite grain size upon the progress and result of isothermal transformation has been published. Davenport and Bain,' and Zimmerman, Aborn and Bain2 have shown that the transformation is definitely relarded in hypereutectoid plain carbon steels at temperatures near and above the upper region of rapid transformation (Ar') when the austenite grains are increased in size. More recently, Griffiths. Pfeil and Allen3 investigated the effect of a series of different heating (austenitizing) temperatures upon the progress of isothermal transformation at 1245°F. (675°C.) and 745ºF. (395°C.) in a medium carbon, low-alloy steel; while they reported no measurements of the austenite grain size, their results suggest that increase in grain size retards austenite transformation at 1245ºF. (675°C), but has no appreciable effect at 745°F (395°C.). The present paper deals with the results of a study of the isothermal transformation of austenite in a single commercial alloy steel in which a fine-grained or a coarsegrained state was induced by appropriate selection of austenitizing temperature. The data are presented in the form of isothermal transformation diagrams, which clearly show that coarsening the grains lessens the rate of transformation of austenite to proeutectoid ferrite and pearlite—that is, at temperature levels above about 1000°F. (540°C.)—but is without significant effect at lower temperatures where the transformation product is bainite or martensite. It is to he presumed that the foregoing statement would be valid, at least in principle, for many other grades of steel; it confirms again that the mechanism of transformation to a pearlitic structure is fundamentally different from that to an acicular structure. A number of related observations were made, which seem to throw some light on the transformation process as it takes place in alloy steels, particularly at temperature levels in the vicinity of 1000ºF. (540°C.), where the transition from lamellar to acicular structures occurs. These data are discussed briefly in the belief that they may lead to a clearer understanding of this aspect of the subject. Material and Experimental Procedure The material investigated was a cornmercial grade of S.A.E. 4140 steel, the composition of which was as follows: 0.37 per cent C, 0.77 per cent Mn, 0.98 per cent Cr and 0.21 per cent Mo. It was hot-rolled to a 1 1/8-in. round bar and normalized by air-cooling from 1800°F. (980°C.).

Jan 1, 1941

By R. J. Hafsten, E. S. Davenport, R. A. Grange

The influence of austenite grain size upon the hardenability of steel is now fairly well understood; for a given austenite, increasing the grain size increases the depth of hardening, and, since the latter is related to the fundamental transformation behavior of austenite, it follows that austenite decomposition must, in general, be retarded by increasing grain size. To date, very little quantitative information bearing directly on the effect of austenite grain size upon the progress and result of isothermal transformation has been published. Davenport and Bain,' and Zimmerman, Aborn and Bain2 have shown that the transformation is definitely relarded in hypereutectoid plain carbon steels at temperatures near and above the upper region of rapid transformation (Ar') when the austenite grains are increased in size. More recently, Griffiths. Pfeil and Allen3 investigated the effect of a series of different heating (austenitizing) temperatures upon the progress of isothermal transformation at 1245°F. (675°C.) and 745ºF. (395°C.) in a medium carbon, low-alloy steel; while they reported no measurements of the austenite grain size, their results suggest that increase in grain size retards austenite transformation at 1245ºF. (675°C), but has no appreciable effect at 745°F (395°C.). The present paper deals with the results of a study of the isothermal transformation of austenite in a single commercial alloy steel in which a fine-grained or a coarsegrained state was induced by appropriate selection of austenitizing temperature. The data are presented in the form of isothermal transformation diagrams, which clearly show that coarsening the grains lessens the rate of transformation of austenite to proeutectoid ferrite and pearlite—that is, at temperature levels above about 1000°F. (540°C.)—but is without significant effect at lower temperatures where the transformation product is bainite or martensite. It is to he presumed that the foregoing statement would be valid, at least in principle, for many other grades of steel; it confirms again that the mechanism of transformation to a pearlitic structure is fundamentally different from that to an acicular structure. A number of related observations were made, which seem to throw some light on the transformation process as it takes place in alloy steels, particularly at temperature levels in the vicinity of 1000ºF. (540°C.), where the transition from lamellar to acicular structures occurs. These data are discussed briefly in the belief that they may lead to a clearer understanding of this aspect of the subject. Material and Experimental Procedure The material investigated was a cornmercial grade of S.A.E. 4140 steel, the composition of which was as follows: 0.37 per cent C, 0.77 per cent Mn, 0.98 per cent Cr and 0.21 per cent Mo. It was hot-rolled to a 1 1/8-in. round bar and normalized by air-cooling from 1800°F. (980°C.).

Jan 1, 1941

By A. E. Outerbridge

It has been generally accepted as a fact that cast-iron, under the influence of repeated shocks, becomes brittle, and will finally break under a blow which otherwise it would have withstood. It will probably surprise metallurgists, therefore, to learn that experiment disproves the supposed fact, and establishes exactly its opposite. The result of about a thousand tests of bars of cast-iron of all grades, from the softest foundry-mixtures to the strongest car-wheel metal, enables me to assert with confidence that, within limits, cast-iron is materially strengthened by subjection to repeated shocks or blows. It is very well known that the usual process of annealing castings—such, for example, as car-wheels—increases their strength by relieving cooling-strains. But it is not well known (if known at all prior to this announcement) that the molecules of cast-iron are capable of movement—for they do not touch each other*—without the necessity of heating the casting, and that they can thus rearrange themselves in comfortable relation to their neighbors, and relieve the overcrowding near the surface of the casting. In more technical words, a molecular annealing may be accomplished at ordinary temperatures which will release the strains in the castings, precisely as does annealing by slow cooling in heated pits or ovens. A statement so surprising should not be made without sufficient data to establish its correctness beyond cavil, since it is contrary to former

Jan 1, 1897

By Alan Bugden

Goedehoop Colliery produces 8 million tonnes of coal a year, principally from room and pillar mining, and is situated in the Witbank Coalfield in the Republic of South Africa. The mine has a long and successful record of producing export quality coal from the 2,4 and 5 seams at depths ranging from 20 to 100 metres using modem mining equipment. Following a number of fatalities caused by large and unexplained roof falls in roadways and intersections of supported ground, a review of the roof control system at Goedehoop was carried out. This led in turn to a programme of underground measurements and surveys. This included detailed investigation of the roof falls, horizontal stress mapping, stress measurement and short encapsulation pull testing on roofbolts. These investigations led to a number of important conclusions in relation to the state of stress in the ground, the roof failure mechanisms, standard of rootbolt installation and performance of the roofbolt system. As a result of the work Goedehoop Colliery has made a number of substantive changes to the roof control management system at the mine. These include: 1. A recognition of the importance of horizontal stress as the main factor responsible for roof falls. 2 The forward planning of roof support based on known features which cause the stresses to be elevated. 3. The introduction of a more effective roofbolt system, which can be more easily installed to a high standard. 4. A response system based on risk assessment and monitoring roof movement on a routine basis. The paper describes the knowledge acquired, the conclusions drawn, the changes made and progress to date.

Jan 1, 2001

By E. Gregory, A. Coucoulas

Carbm dioxide, which exists metastably as a constantly subliming molecular solid in a normal room-temperature environment, has been shown to exhibit many microstructural features which are similar to those observed in metals and ceramics at temperatures approaching their melting points. An examinution has been made of some of the factors affecting a brittleness condition known as "smzdiness" which occurs in solid carbon dioxide. It has been shown to be highly dependent on manufacturing and storage conditions and is thought to be a marked intergranu-lay brittleness which results from a combination of excessive grain growth and a concentration of gas-filled pores at the grain boundaries. In the course of an investigation carried out to explain certain physical and mechanical properties of solid carbon dioxide, observations were made of the microstructure and fragmentation of samples after fabrication and storage under varying conditions. Many similarities between the structures of solid carbon dioxide observed under ambient conditions and those existing in metal and ceramic systems at temperatures approaching their melting points have been observed. There are, however, important differences between solid carbon dioxide and the common metallic and ionic solids which result primarily from the differences in the nature of the bonding forces. Despite these differences, the relative ease with which certain microscopic observations can be carried out, may make solid carbon dioxide a useful material model for the physical metallurgist and the ceramist. It could also prove a valuable material for educational purposes where it is required to illustrate grain phenomena which normally can only be seen with the aid of a high-temperature microscope, and after prolonged chemical or thermal etching.

Jan 1, 1963

By E. A. Anundsen

The prevention of accidents is considered a necessity at all branches and divisions of the Phelps Dodge Corporation copper-producing operations, and since there is a continual exchange of data on safety accomplishments between the various units, their safety programs are fundamentally similar. Variations in accident-prevention methods result from a difference in emphasis rather than from a difference in the elements themselves. The main copper-producing operations of the corporation ore conducted in Arizona and distributed as follows: Copper Queen Branch, mines division, Fisbee, and smelter division, Douglas, Aria.; Morenci Branch, mines division, Morenci, and smelter division, Clifton, Ariz.; New Cornelia Branch, Ajo, Ariz.; and United Verde Branch, mines division, Jerome, and smelter division, Clarkdale Ariz. As it is not feasible to describe here the safety programs of all branches and divisions, the program at the Clarkdale smelter has been selected for discussion. The United Verde Brach includes the mine and smelter purchased by the Phelps Dodge Corporation in February 1935 from the United Verde Copper Co. The mine at Jerome and the reduction works at Clarkdale are designated, respectively, as the mine and smelter divisions.

Jan 1, 1939

By Gokhan Inci

Stability problems with dam spillways on existing landslides and appropriate mitigation measures to remedy them are ongoing concerns for geotechnical engineers. The first successful application of drilled piers as stabilizing structures under the spillway was at the Trinity Dam in Sicily, Italy. ?Underpinning? was considered as an alternative to spillway relocation during the Alpaslan 2 embankment dam design in eastern Turkey. Based on the available literature the first application of drilled piers to stabilize a spillway chute in the U.S. was at the Ralston Dam in Colorado. Ralston Dam, which is a 175-foot-high zoned fill dam located 15 miles northwest of downtown Denver, was built in the late 1930s. The concrete spillway for the dam was built on the Pierre Shale Formation in the left abutment. Since reservoir operations began, mass movements have occurred downstream of the chute area. These movements have required periodic spillway maintenance. After the occurrence of recent movements and because of high piezometeric levels, URS was contracted by Denver Water to develop a more permanent solution by the installation and monitoring of additional instrumentation, analysis of slope stabilizing measures, design, repair, and reconstruction of the distressed section of the spillway chute. With state of the art modifications that include: 1) a stabilizing berm with a toe trench that improves the global stability; 2) seepage prevention and control measures that prevent the infiltration of water; and 3) the structural support of the replaced chute section with drilled piers and reinforced concrete the probability of future displacements or other problems have been reduced for the Ralston Dam Spillway.

Jan 1, 2007

By Earl S. Bardwell

The structural relations existing between cuprous oxide and copper were first systematically studied by Heynl; who suggested that a study of the microstructure of refined copper might be substituted for the analytical methods in vogue for determining the oxygen content of copper coming from the refining furnace. Hofman, Green and Yerxa,2 in their paper A Laboratory Study of the Stages in the Refining of Copper, working along the lines suggested by Heyn, showed that a study of the microstructure could be made to yield a correct estimate of the oxygen content of refined copper. In order to determine the oxygen content of the specimen of refined copper under examination a photomicrograph was first made. From the relative areas of copper and eutectic, the percentage of cuprous oxide and the corresponding percentage of oxygen were then readily calculated. It was found that the values for oxygen thus obtained corresponded closely with the analytical results. With the idea of utilizing this method of determining the oxygen content of each charge dipped from the refining furnaces at the Boston & Montana Reduction Plant, the physical testing laboratory was equipped with suitable apparatus for carrying out the work. It may be of interest to describe certain of the methods which have been worked out in this connection and give such data as have been obtained bearing on the effect of the oxygen content of refined copper upon its conductivity. Apparatus.—For the benefit of those who may be unfamiliar with metallographical apparatus and methods and may be interested to know what equipment is required, a few words with regard to the apparatus are in place at this point.

Jan 1, 1914

By John Garcia

THE presence of carbon de terre along the banks of the Illinois river was noted by the members of the Joliet and Marquette expeditions in 1673, and that may be referred to as the birthday of coal in the Middle West. The march of progress in the majority of indus-tries radiating from Chicago-one of the phenomena of history-is due in no small measure to this same carbon de terre and to the development and exploita-tion of the vast coal resources, which nature in a generous mood spread so lavishly over almost the en-tire state. The geological records indicate that coal-bearing rocks underlie three-quarters of Illinois, in-cluding 85 of the 102 counties and the entire area is estimated at from 36,000 to 42,000 square miles. Not all of the coal in this great area may be mined under the conditions existing today; producers are now taking the "cream" since industry demands the best quality and the lowest cost, thereby forcing competition among operators, which, in turn, com-pels the development of mines in those areas where the coal may be most readily .won, leaving the coal that is more difficult and expensive to mine to pos-terity. This is not such a bad arrangement, since the engineers of succeeding generations will enjoy the advantage of the experience of their ancestors, where-by they should profit and know how to mine a 2-ft. seam with as much economy and dispatch as we today work coal of thrice that thickness. During the period between 1830 and 1850, Illinois coal-mining progressed from the art of scratching along the outcrop to the development of small mines, mostly slopes, drifts and shallow shafts, but the real progress in the industry was coincident with the con-struction of railroads.

Jan 2, 1927

By Francis Church Lincoln

I. Situation and Surroundings, The Promontorio mine is situated at the northern end of the Sierra San Francisco de Coneto, in the town of Promontorio, Partido of El Oro, State of Durango, Mexico. As shown in the sketch-map, Fig. 1, the nearest railroad station is Chin-acates on the Mexican International Railroad, 82 miles north of the city of Durango. The mine is 16 miles north of the sta-tion by air-line. It is reached by means of a good wagon-road which first crosses the Guatimapé Plain, passing the ranches of San Antonio and San Julian, to Estacion—a distance of about 15.5 miles—and then entering the mountains crosses the Sierra to Promontorio—a further distance of 11.5 miles— making in all a distance of 27 miles by road from railroad to mine. Promontorio is just beyond the summit of the range, at an elevation of about 8,000 ft. above sea-level, or 1,350 ft. above the Chinacates station. The Castillo de San Francisco, the highest peak in the Sierra, has an altitude of 10,000 ft., and the Promontorio road crosses the summit of the ridge at an elevation of 9,000 ft. by a pass just below this peak known as the Puerto del Almagre. The Promontorio mill is situated at Santa Inés, 2 miles by tram or 3 miles by wagon-road to the north of Promontorio and about 600 ft. lower. The Sierra San Francisco de Coneto decreases in height towards the north and west till it comes to an end at the Mel-chor Arroyo on the ranches of Melchor and Ramos. Beyond this arroyo another range, the Sierra de la Candela, begins. In the vicinity of the Promontorio mine the hills are very rugged and the surface is furrowed by ravines which contain running streams during the rainy season-—July, August and

Jan 1, 1908

By H. A. Coy, H. B. Henegar

The Mascot mines of the American Zinc Co. of Tennessee are situated in the Holston River valley, in Knox County, Tennessee, about 13 miles (20.9 km.) east of the city of Knoxville, and form a property of three operating shafts and one open pit. A second open pit is located at Jefferson City about 16 miles (25.8 km.) east of the Mascot mines. Geology Topography.—The principal topographical features of the region within which the zinc deposits occur is a series of parallel northeast and southwest ridges which reach altitudes of 200 to 400 ft. (61 to 122 m.) above the valley. These ridges are formed of resistant formation such as sandstone, quartzites, etc., while the valleys are occupied principally by limestone, including Knox dolomite, and by shale and other formations subject to quick erosion. The Holston River valley is wide and open with a rolling surface. Sink holes are common to the limestone portion, the general aspect of the valley being that of well-rounded hills with low intervening valleys superimposed upon which is a characteristic sink-hole topography. General Geology.—According to Keith, the rock formation of the area extends from the lower Cambrian into the Silurian. The region has undergone severe deformation with hcavy faulting, the underlying Cambrian having been brought to the surface by a series of low angle thrust faults, the strike of the faults and formations paralleling the general northeast and southwest direction of the topography and dipping at varying angles to the southeast. In general, the Cambrian quartzites, sandstone, etc., occupy the ridges while the Cambro-Si urian dolomites, limestone and shales occur principally in the valleys. Of the latter, the Knox dolomite is of particular interest to this paper in that it is the ore carrier in the Mascot area. The ore is associated with more or less irregular breccia zones, the degree of brecciation varying from a fine crushing to a breaking that involves blocks of large size. The breccia zones

Jan 1, 1918

The use of teleoperation in mining is increasing due to requirements to improve safety and reduce the number of people required to work in remote and difficult environments. We recently completed a project to develop a teleoperated control system for a rock breaker at an iron ore mine in the Pilbara region of Western Australia, with the objective of demonstrating the feasibility of remote rock breaking over long distances. This required controlling both the rock breaker and an array of pan-tilt-zoom (PTZ) cameras using joysticks. Controlling the cameras distracted operators from the primary task of controlling the rock breaker to position and fire the hammer. This lengthened task times as both the operator's attention and their hands have to swap between different control interfaces. In this paper, we present a novel design using human eye gaze as an interactive input for the remote camera control. It follows a simple and natural design principle: Whatever you look at the screen, it goes to the centre. A prototype system has been implemented by integrating computer vision based eye tracking technology, with the advantage of being real-time, robust and marker-less. We conducted a user evaluation, where users undertook a control task while obscuring the direct view of the working area and using a remote camera to transfer the live video stream as the visual feedback. Subjects were required to participate in the experiment using eye tracking camera control and traditional joystick control respectively. The statistical analysis of objective measures indicated that our novel eye tracking control significantly outperformed the joystick control. The results of the post-experimental subjective measures also revealed much higher user preference for using eye tracking control, which provides clear evidence that this design is a better interface for remote camera control in mining teleoperation settings.

May 1, 2010

By S K. Schwank

Trench cutter systems have been used in civil engineering for the least 30 years for the installation of deep cut-off walls, retaining walls and foundation systems. The systems are constantly advanced to achieve greater depth, penetrate through harder rocks a provide a bigger footprint of the cutter. The state-of-the-art equipment can reach down to 250 m vertical depth and penetrate all different types of soils and rocks up to 150 MPa unconfined compressive strength.In mining, especially in commodities with a high value and where the ore deposit has a small footprint, cutter mining with vertical attack from the existing ground level will be a new, cost-efficient approach where conventional open pit mining is not economically feasible due to a high stripping ratio. The same applies for open pit mines that have reached the end of their conventional mine life and where going underground is also uneconomical. The BAUER Cutter Mining System, which has been adapted to the special needs of mining, is a new technology that will allow mining at depths of up to 250 m.The same system can be also applied to ore dykes, be it vertical or slightly inclined, concentrating the excavation on the actual orebody and minimising the strip ratio and the contamination of ore. The system can be adapted to the dimension of the dykes or veins and to the rock conditions.BAUER’s latest approach is to use the vertical cutter mining technology for the extraction of sea floor massive sulfides from the seabed in deep ocean waters. Due to the compact footprint of the system and the vertical attack for mining, extraction of the ore can be concentrated on the hot spots, minimising the environmental impact on the sea floor both for mining and manoeuvring the remote-controlled mining tool.CITATION:Schwank, S K, 2015. Cutter mining – crossover technology from civil engineering to mining, in Proceedings Third International Future Mining Conference, pp 95–100 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 4, 2015