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By E. M. Norris

Phosphate deposits are distributed widely over the earth's surface. Of the known areas of deposit, eight fields are of particular interest because of their vast reserves of high grade phosphatic material and the volume of their production that goes to the world's great consuming areas. These fields, in the order of their present economic importance, are situated respectively in Florida, French Morocco, Kola Peninsula of U.S.S.R., Tunisia and Algeria, Tennessee, Montana-Idaho-Wyoming-Utah, Ocean and Naru Islands in the Gilbert group, and in Egypt. The Rocky Mountain deposits have a comparatively low ranking in the phosphate trade of today, but this field contains one of the largest known reserves of phosphatic material, associated with which are recoverable trace minerals, which are of increasing importance in our national economy. The first discoveries of phosphate rock in the western states were recorded in Cache1 and Rich2 counties in Utah, respectively in 1889 and 1897. Mining operations were begun on these deposits near Montpelier, Idaho, in 1906. During the latter year geological studies of the phosphate beds were started by Weeks and Ferrier of the U. S. Geological Survey. These studies have been continued to the present day by a distinguished roster of the Survey's technicians. As a result of this systematic exploratory program, the Survey has published a series of bulletins, papers, and maps, which provide the mining public with a comprehensive study of the exposed

Jan 1, 1949

By John S. Ball

Aniline points have been used to some extent for more than 20 years. to indicate the types of structures in hydrocarbons and thus to analyze mixtures of hydrocarbons . This type of analysis has been applied - principally to the low -boiling hydrocarbons found in the gasoline range . Although there is some disagreement as to their merits , both aniline point and diesel index (aniline point in degrees Fahrenheit times A.P.I. gravity at 60 ° F. divided by 100) are used rather extensively for evaluating ignition qualities of diesel fuels . In recent years aniline points have been employed in the study of lubricating - oil fractions . They also have been used to predict : the tendency of different oils to cause swelling of synthetic rubbers.5/ Recent standardization of the aniline - point determination by the American Society for Testing Materials has encouraged wider use of this test . Considerable data concerning , aniline points and critical solution temperatures in aniline have been accumulated in the course of a study of related subjects . Thesc data , together with some original results , are presented here in the hope that they will prove useful to other worker's in this field ...

Oct 1, 1943

By S. R. McCutcheon, D. R. Lentz

"Abstract - The 12.1 Mt Brunswick No. 6 Zn-Pb-Cu-Ag massive sulfide deposit (New Brunswick, Canada) lies between two subaqueous felsic volcanic formations near the base of the Middle Ordovician Tetagouche Group. The footwall comprises rhyodacitic pyroclastic rocks (Nepisiguit Falls Formation), whereas the hanging wall comprises a sequence of rhyolitic flows, breccias, and hyaloclastites (Flat Landing Brook Formation), with an age difference of less than 3 m.y. The Brunswick No. 6 deposit is a proximal autochthonous deposit with a well-zoned massive sulfide body and a basal Cu zone that, at depth, develops into a stockwork stringer sulfide (feeder) system. The massive sulfides are capped sharply by a layered magnetite-chert unit that extends regionally beyond the deposit. The deposit has a keel shape (sheath) formed by the F1F2 interference pattern. The heterogeneous ductile deformation and upper greenschist-grade regional metamorphism has transposed many of the epigenetic stockwork structures and alteration within the host sequence. Hydrothermal alteration is much more extensive, both vertically and laterally, in the footwall (a few 100 m) than in the hanging wall (<100 m). Anomalies farther up in the hanging wall sequence seem to be associated with independent alteration systems related to the rhyolite domes. The least-altered footwall units exhibit keratophyric alteration (albite or adularia) and weak Mg enrichment (chlorite). More intense micaceous (sericite and Mg-rich chlorite) alteration occurs around the footwall sequence. The transposed stockwork stringer sulfides are typically composed of Fe-rich chlorite (± sericite, ± silica) with pyrite, pyrrhotite, chalcopyrite, arsenopyrite, and sphalerite. The (Fe2O3T+MgO)/(Na2O+K2O) and base metal alteration indices are the best practical lithogeochemical vectoring tools at this deposit. Sommaire - Le gîte de 12.1 Mt de sulfures massifs de Zn-Pb-Cu-Ag Brunswick No.6 est localisé entre deux formations volcaniques felsiques sous-marines situées près de la base du Groupe de Tetagouche d’âge Ordovicien Moyen. Le mur consiste en roches pyroclastiques rhyodacitiques (Formation de Nepisiguit Falls) tandis que le toit consiste en une séquence de coulées, de brèches et d’hyaloclastites de composition rhyolitique (Formation de Flat Landing Brook); la différence d’âge entre les deux est de moins de 3 m.y. Le gisement Brunswick No. 6 est un gîte autochtone proximal comprenant un corps de sulfures massifs clairement zoné ainsi qu’une zone cuprifère basale qui passe progressivement à un stockwork de filonnets de sulfure en profondeur (feeder). Les sulfures massifs sont abruptement surmontés d’une unité laminaire de chert et de magnétite dont l’extension par delà le gisement est régionale. Le gisement affecte la forme d’une quille (fourreau) résultant d’un patron d’interférence F1F2. Plusieurs des structures épigénétiques du stockwork et des patrons d’altération de l’encaissant ont été transposés par la déformation ductile hétérogène ainsi que par le métamorphisme régional au faciès des schistes verts. L’altération hydrothermale est beaucoup plus importante, tant verticalement qu’horizontalement, dans le mur (quelques 100 m) que dans le toit (<100 m). Les anomalies situées plus haut dans le mur semblent être reliées à des systèmes d’altération indépendants associés aux dômes de rhyolite. Les unités les moins altérées du mur une altération kératophyrique (en albite ou en adulaire) ainsi qu’un faible enrichissement en Mg (chlorite). Une altération en mica (séricite et chlorite magnésienne) plus intense est présente autour de la séquence du mur. Les sulfures du stockwork de filonnets transposés consistent typiquement en chlorite ferrifère (± séricite, ± silice) accompagnée de pyrite, de pyrrhotite, de chalcopyrite, d’arsénopyrite et de sphalérite. L’indice d’altération (Fe2O3T+MgO)/(Na2O+K2O) et l’indice des métaux usuels sont les outils d’exploration les plus appropriés dans ce gisement."

Jan 1, 2006

By E. P. Youngman

The rapidly growing demand for titanium pigments has aroused new interest in actual and potential sources of supply of titanium- bearing ores , which only a comparatively few years ago were almost unmarketable . This paper , which supplements a general circular entitled " Titanium" ( Information Circular 6365 ) , represents a summary of current trade literature and Government reports , together with some hitherto unpublished material that has accumulated in the files of the Bureau of Mines . The purpose of this pamphlet is simply to indicate the commercial possibilities of the deposits , and the discussion is confined almost entirely to the three commercial ores , ilmenite , rutile , and magnetite ( titaniferous iron ore ) .

Oct 1, 1930

By Flavelle IV

A survey is made of changes in the technical status of a number of western world copper extraction and refining operations over the past 20 years. Specific developments in pyro- and hydro-metallurgy and refining practices are identified together with factors in the changing environment of the industry which has influenced their adoption. Nickel extraction and refining is similarly discussed.The replacement of traditional technology by more attractive alternatives has occurred in a considerable number of operations. The develop-ment and status of new continuous smelting processes, advances in hydrometallurgy and refining innovations which emerged during the 1960s and early 1970s is discussed. The varying experience in commercial acceptance of these new technologies is noted.Finally some possible future directions are canvassed for both operators and the research and development institutions.

Jan 1, 1985

By R C. A Minnitt

The Witwatersrand Supergroup is host to the world’s largest gold deposits. The location, quantity, grade, continuity and other geological characteristics of a Mineral Resource are either known, estimated from specific geological evidence and knowledge, or interpreted from a well constrained and portrayed geological model. Establishing such a model is an integral part of the evaluation process in the Anglogold Ashanti (AGA) group, and is referred to as a Geoscience Business Model for the mining operations. The geological model established over the years has relied on detailed descriptions of the mineralisation, and understanding of the regional and local geology of the Witwatersrand sediments, in the West Wits and Free State goldfields. The processes of data collection in regard to underground stope and developing mapping, structural and sedimentological mapping, and the geological inputs to mine planning systems are described, together with aspects of drilling, sampling, grade control, and data management. Anglogold Ashanti’s Geoscience Department employs a complex and unique process to generate the Mineral Resource, including a 3D geological structure model of the orebodies which are usually highly faulted, and a robust mineralisation/facies model on which the decisions about domain boundaries are established. A Mineral Resource Inventory System (MRIS) has a dynamic graphic interface to the resource database that is used for compiling the resource statement. It is also used to determine the gold-called-for, as well as short and long-term planning. A unique estimation process using the extensive closely spaced stope face sampling database and the more widely spaced surface drilling information is used in combination in the Macro Co-Kriging estimation. The use of different support sizes in the C0-Kriging process is preceded by the equally unique ‘clusterisation’ and ‘acceptorisation’ procedures by which the data are quality controlled and assured prior to their use in the kriging process. The Mineral Resource and Ore Reserve estimates are classified according to the SAMREC code through a method that ensures that they are compliant, auditable, transparent and reconcilable with previous Mineral Resource and Ore Reserve statements.

Aug 22, 2011

By J. J. Hoeppner

Lignite samples were collected so as to be widely representative of the extensive deposits in the western north-central area. These were carbonized at temperatures ranging from 450° to 550° C., according, to a standardized procedure. In general, product yields varied; extremes obtained on selected samples show char recoveries on the moisture- and ash-free basis as 56.7 percent for slack lignite or "leonardite" to 80.8 percent for a concentrate of the fusain component from a typical face sample; normal lignite samples averaged approximately 70 percent. Tar-plus-light-oil yields ranged from 3.3 percent for the fusain concentrate to 11.0 percent for a normal sample, averaging approximately 8 percent; gas recoveries varied more widely both in yield and in composition, ranging, from 10.0 percent to 27.7 percent, the latter being from leonardite and quite high in carbon dioxide. Sampling was conducted with the view of representing, as nearly as possible, all beds delineated by Brant (2);4/ many are necessarily missing since collection was confined largely to worked deposits. Data presented in this report indicate a general uniformity of North-Central lignite in respect to low-temperature carbonization, with a few possible exceptions of a local nature. When processed according to the indicated conditions, maximum tar yield may be realized with minimum loss of recoverable heating value of the original coal. Natural weathering of lignite, however, does affect tar yield adversely and should be held to a practical minimum in any commercial operation.

Jan 1, 1956

By E. Stamboliadis

Gravity separation techniques were used in the early years to extract native metal nuggets and flakes from placer gold deposits. This was relatively easy for visible metal grains. As the size of the grain becomes smaller traditional gravity separation techniques become inadequate to recover native gold. Cyanidation was invented as a solution to the problem. According to it, gold and other precious metals are dissolved in water by sodium cyanide. The result was a drastic increase of world gold production but at the same time environmental issues were raised. In Greece gold mining has become equivalent with the absolute destruction of the environment and is under extinction. In the last years a new type of gravity equipment have been produced which create a gravitational field up to 200 G and can separate gold from gangue minerals at sizes below 50 µm. The strong gravitational field is created by centrifugal forces and the separation occurs in a fluidized bed, formed by water flow. Accumulations of finely disseminated native gold are found in the sedimentary sequence of the Flysch of the Ionian Zone. The main gold minerals are gold and electrum present as free metal flakes and micro nuggets in the size range between 5-250 µm. Test work, using the Falcon SB40 centrifugal concentrator, at the Department of Mineral Resources Engineering at the Technical University of Crete, has shown that this particular type of gold ore can be processed by gravitational methods that require no reagents and are environmentally safe.

Jan 1, 2003

By Thomas Bannon

PROSPECTING for oil in Spain has been going on for many years but only in a very haphazard way and without adequate geological or technical advice. Shallow wells have been drilled in several provinces but, for the most part, they have been doomed to failure from the beginning because of unfavorable geological locations, inadequate drilling equipment inexperienced operators, or lack of sufficient capital. Geologists seem to agree that the most favorable chances for commercial fields are in the northern part of Spain where the petroliferous Triassic beds underlie Cretaceous and Tertiary sediments. The prov-vinces of Santander, Burgos, Alava, Vizcaya, Navarra, and Guipuzcoa seem to offer the most promising localities. Several shallow wells have been drilled near Villamartin about 60 Km. northeast of Cadiz. One of these wells produced a small quantity of light oil but was never operated. The Spanish Government has been drilling on a well in this district for some time, using the Russian free-fall drilling system. The present depth is about 3000 meters. Several years ago the Compania Petrolera Franco-Espanola drilled a well to a depth of about 700 meters near Elorrio, province of Vizcaya. A diamond-core drill was used. The well was located on vertical Cretaceous beds near an igneous dike. The same company, in March, 1923, made a new location about 500 meters away from the first well and the same distance from the dike, in beds dipping about 80°, and is now drilling its No. 2 well. The last depth reported was about 200 meters.

Jan 3, 1924

By K. Chandrasekaran

Carbon-in-leach (CIL) is conventionally used in gold processing operations when preg robbing components are present in the ore. The CIL process is becoming attractive even in other situations when preg robbing is not a factor. This article discusses the situations in which the CIL circuit can be applied. The results of leach-carbon-in-pulp (CIP) and CIL circuits at Newmont Gold&apos;s Mill No. 2, No. 4 and No. 5 are presented for comparison: Mill No. 4 was initially designed for a throughput of 4.1 kt/d (4500 stpd). It is presently operating at an average throughput of 6.6 kt/d (7300 stpd) without significant changes to the original design. The design considerations of the Mill No. 4 CIL circuit are discussed. The design of any processing facility represents a series of decisions. The final design options should ultimately be resolved based on economic as well as technical considerations. Every design decision represents some sort of compromise. From the designer&apos;s view point, these decisions are made with the conviction that the final product represents the most prudent long-term expenditure. The design throughput rate is a decision reflecting a maximum return for the capital and operating costs that the plant will incur over the life of the mineral resource. The result is a plant that is not operator proof or maintenance free because it would be too costly to build. At some point, the incremental increase in the level of capital expenditure would not adequately compensate for the lower

Jan 1, 1991

Council and Standing Committees, 1978-1979 President: Dr M. G. Atmore. Vice-Presidents: D. A. Viljoen and Dr P. R. Jochens. Honorary Treasurer: J. K. E. Douglas. Immediate Past President: P. A. von Wielligh. Members of Council: J. D. Austin, A. N. Brown, H. E. James, Prof. R. P. King, Dr D. G. Krige, Prof. F. Q. P. Leiding, D. G. Malan, C. S. McPhail, J. C. Mostert, G. Y. Nisbet, H. G. M. Rose, W. T. Ruhmer, G. C. Thompson, R. A. von Maltitz. Chairman, Witbank-Middelburg Branch: T. S. Wilmot. Chairman, Orange Free State-Klerksdorp Branch: H. M. W. Eschenburg. Past Presidents Serving on Council: R. J. Adamson, H. Britten, J. K. E. Douglas, Prof. D. D. Howat, Dr J. P. Hugo, D. G. Maxwell, Prof. R. P. Plewman, Dr R. E. Robinson, Dr M. D. G. Salamon, P. W. J. van Rensburg. Standing Committee Chairmen: Membership, Dr P. R. Jochens ; Technical Programme - Metallurgy, Prof. R. P. King ; Technical Programme - Mining, H. G. M. Rose; Vacation School - Metallurgy, J. C. Mostert; Vacation School - Mining, D. G. Malan/J. D. Austin; Awards, P. A. von Wielligh; Excursions, D. A. Viljoen; Adjudication, P. A. von Wielligh; Constitution, Rules and Policy, P. A. von Wielligh; Monograph Series, Dr R. E. Robinson; Professional and Technician Train¬ing Committee, Dr M. D. G. Salamon; Career Guidance, D. G. Malan; Phoenix National Committee, Dr R. E. Robinson; 1982 World Congress, Dr M. G. Atmore; Witbank Coal Colloquium, Dr P. R. Jochens; Mines and Works, P. A. von Wielligh.

Jan 1, 1979

By Migen Dibra

Antitrust and competition laws are designed to protect the free markets and promote competition in order to assure a dynamic and efficient economy and to provide competitive prices for quality products and services. They apply to mergers and acquisitions as well as to joint ventures especially among competitor companies who possess market power and these include collaborations on research and development. If it is determined that these actions are likely to substantially prevent or lessen competition the courts might dissolve, stop, alternate them, etc. Two new factors affect this process today: The role of new technologies and the markets globalization. They both have a considerable effect on the way these laws are interpreted by the courts and on their eventual amendments in order to reflect the new reality. A new applied technology and the globalization separately or together may change the factors that determine how anticompetitive a merger or acquisition between competitors may be and may also serve as a basis for amending the antitrust and competition laws. In this paper, a short review of the recent mergers and acquisitions of various companies has been carried out along with an abridged analysis of the current antitrust and competition laws in USA, Canada and European Union in the view of their capacity to handle the new reality. Some related court decisions are also examined and several examples are given in order to illustrate the influence of new technologies and globalization in interpreting the existing laws and on their amendment possibilities.

Jan 1, 2006

A. L. BLOMFIELD, ? Colorado Springs, Colo. (written discussion?).¬I congratulate the author on bringing out a paper of real service to the profession. His contention of uniform size in balls is borne out by my own experience; in coarse crushing at the Golden Cycle in 6 by 6-ft. (1.8 by 1.8-m.) ball-mills we unquestionably gain by screening out the small balls once or twice a month. The point of gaging the ball size to be used by the uniformity of screen sizing is of particular interest. The necessity of sufficient return feed from classifier to the ball-mill is sound and clearly shown. In connection with this, I wish two further points had been gone into as thoroughly: (1) The effect of the quality of classification. In general, it is true that the smaller the per cent. of undersize in the feed the more effective is the mill&apos;s work. This is true on a bucking board, in tube-mills, ball-mills, and grinding pans. Given the possibility of returning. a full-feed load to any mill, it has been my experience that the effective work in the grinder is almost proportional to the quality of the return feed. (2) Again speaking generally, the shorter the tube-mill the greater is the quantity of return feed necessary to keep it loaded. The classification thus keeps the oversize in the mill more free from finished product and thus the crushing more efficient. It is very easy to overload any long mill with too much return

Jan 4, 1919

(Under this heading will be published notes sent to the Secretary of the Institute by members or other persons introduced by members) Member, aged 32. Fifteen years&apos; experience in the mining, quarrying, and manufacture of gypsum and gypsum products, as purchasing agent, designer, operating manager and managing executive. Thoroughly familiar with the business in all branches, especially the organization of efficient producing forces and machinery and the value of cost and their application to manufacturing. Desires responsible position with a financially reliable concern in the same or similar business in which an interest may be obtained at a later date. Now doing consulting work, but free for appointments after April 1. New York or Philadelphia. No. 345. Member, technical graduate. Unmarried. Aged 32. Seven and one half years&apos; experience in mining, timbering, and mine sampling. At present, and for past two and a half years, mine sampler for well known and highly successful mining company. Desire change. Go anywhere. Prefer assisting Mining Engineer. No. 346. Member, 40 years old. 18 years&apos; experience in examinations and operation in the United States, Mexico and South America. Especially successful with poor class of labor. Open for engagement in any part of the world, in technical, administrative or consulting work. No. 347. Member, technical graduate. Sixteen years&apos; experience as engineer, superintendent, and manager in metal mines. Exploratory . work, developing and equipping new properties. Operation of large mines, and various systems of mining. Low costs. Specialized in iron and copper mining, but have had some experience in zinc, lead and pyrite mining. No; 348.

Jan 4, 1917

This paper is essentially an address, rather than a detailed presentation of facts, because the third edition of `Nuclear Electricity - An Australian Perspective&apos; has just been completed and will be available for the seminar. That 96-page booklet contains a lot more information than The AusIMM would be prepared to print in the seminar proceedings. Hence I have kept this paper brief, and ask readers to obtain a (free) copy of Nuclear Electricity at the seminar or from The AusIMM. It can be read as a supplement to the paper (or vice versa). According to one of Australia&apos;s well known critics of nuclear power, Professor Ian Lowe, `the pro-nuclear lobby&apos;s predictions of the future use of nuclear energy .... have been regularly and consistently wrong by large amounts, always overestimating the future demand for uranium" (Aust. Society, April 1989). While I do not accept this as a bald statement applying to all those in favour of increased use of nuclear power, there is sufficient truth in it for it to be credible. Certainly in the 1950s and the 1960s, when the new technology for producing controlled power from atomic fission was first being commercialised, there were some very exaggerated projections of the role of nuclear power. Many people thought that it would take over from fossil fuel fired electricity generation in much the same way as the motor vehicle took over from horse-drawn transport. And these early projections were not simply concerned with electric power generation, they included excavating harbours and digging canals with nuclear explosives.

Jan 1, 1989

By Leonardo Massone

The p-y method is one of the most popular methods in pile design and has been calibrated for various boundary conditions using numerical and experimental studies during recent years. Most studies on reinforced concrete (RC) piles have included the impact of flexural nonlinearity, (e.g. nonlinear moment?curvature relations) but not considered associated pile shear deformations when deriving p-y curves from field data. Common p-y curves may be better applicable for piles with flexure dominated failures (e.g. piles with free- head boundary conditions). For piles with fixed head boundaries (i.e. rotation restrained piles) shear deformations could be of significant influence. To study this problem, a coupled shear flexure interaction model for axial-bending-shear behavior coded in OpenSees is applied to a 0.61 m flagpole and a 0.61m fixed head pile specimen to investigate the possible influence of shear deformations to the overall pile responses. The surrounding soil is represented by p-y curves derived from prior large scale testing on piles with similar boundary conditions. Analysis results show that for flagpole piles, shear forces and shear deformations were insignificant. Considerable contributions of pile shear displacements and forces were observed for the fixed head pile, with shear displacements contributing up to 40% of the total pile displacement. Results suggest that nonlinear shear deformations for reinforced concrete piles should be considered for fixed-head or similar conditions, and that currently used p-y curves may underestimate the actual lateral pile displacement and possibly lead to unsafe design for the particular boundary condition.

Jan 1, 2011

Council and Standing Committees-1984/85 President: J.D. Austin Vice Presidents: H.E. James and Dr H. Wagner Immediate Past President: Prof. R.P. King Honorary Treasurer: Prof. D.G. Krige Members of Council: B.C. Alberts, Prof. S. Budavari, E.B. Crocker, N.J. Devine, C.E. Fivaz, J.S. Freer, Prof. G.G. Garrett, J.J. Geldenhuys, Dr A.K. Haines, R.W.O. Kersten, Dr B.K. Loveday, I.D. Matthews, G. Maude, H.G. Mosenthal, B.E. Protheroe, Dr O.K.H. Steffen, Dr P.T. Wedepohl Chairman, Witbank/Middelburg Branch: W.C. Mather Chairman, Orange Free State/Klerksdorp Branch: Dr M.A. Orridge Past Presidents Serving on Council: Dr M.G. Atmore, Prof. A.N. Brown, Dr P.R. Jochens, G.Y. Nisbet, Prof. R.P. Plewman, Dr R.E. Robinson, Prof. M.D.G. Salamon, P.W.J. van Rensburg, D.A. Viljoen, P.A. von Wielligh Standing Committee Chairmen: Adjudication, Prof. R.P. King; Awards, Prof. R.P. King; Constitution, Rules and Policy, Prof. R.P. King; Excursions and Banquet, B.E. Protheroe; Journal, H.E. James; Membership, Dr H. Wagner; Phoenix National Committee, Dr M.G. Atmore; SAIMM School-Extractive Metallurgy, J.S. Freer; SAIMM School-Mining, Prof. S. Budavari; Special Publications, J.D. Austin; Technical Programme¬Extractive Metallurgy, Dr B.K. Loveday; Technical Programme-Mining, J.J. Geldenhuys; Technical Programme-Physical Metallurgy, Dr P.T. Wedepohl; Training, Career Guidance and Education, Prof. R.P. King; World Mining Congress-National Committee, Prof. R.P. Plewman; Working Group Physical Metallurgy, Prof. G. G. Garrett

Jan 1, 1985

By Chapman Young, Donald E. McCarthy

Many hard rock tunneling projects, where the majority of excavation can be accomplished with TBMs, will still require considerable specialized excavation which can not be done with a TBM. This secondary excavation, involving cross cuts, galleries, flattening of the invert, increases in bore diameter, et cetera, may be accomplished with conventional drill and blast, applied on a small scale and usually with fracture control techniques, or with mechanical splitters. The problems of using explosives in many of these cases and the high cost of mechanical splitting excavation make the consideration of other approaches attractive. The PCF rock excavation method, which has recently been reduced to commercial practice for mine-development excavation, offers an attractive alternative to drill and blast and mechanical splitters. With the PCF method the rock is excavated utilizing a small-charge, propellant-driven, controlled, penetrating-cone fracture process. Excavation is carried out continuously by combining the PCF hardware with integrated mucking capabilities on a carrier which remains at the excavation point. In addition to the benefit of providing for complicated excavation geometry, the PCF method also causes minimal damage to the remaining rock which will significantly reduce ground support requirements. In very bad ground, the continuous nature of PCF excavation allows ground support to be applied as limited sections are exposed thus reducing both the duration and extent that the ground would be free to move. Data on PCF excavation parameters, as measured in actual mining operations, indicate that crosscuts, galleries and the like could be excavated at considerable cost savings compared to drill and blast or mechanical splitters.

Jan 1, 1995

In a previous paper in these Proceedings(l) it was shown from a study of the bore&apos;logs and analyses then available, that the brown coal seams of the Latrobe Valley areas show progressive changes in composition with increase of stratigraphic depth, equivalent to a rise in rank: These changes appear as:(i) An increase in ultimate carbon and hydrogen, calculated on a dry, ash-free basis, and(ii) An increase in calorific value, calculated on the, same basis, each of the order of 1% per 100 ft. of depth, and(iii) A decrease in moisture content of the order of 0.5% to 1.0% per 100 ft. of depth. The decrease in moisture content was found to be less regular than the other changes. In some bores the moisture content remained more or less constant throughout a single seam, or fluctuated slightly, decreasing stepwise on passage to the seam below.It was noted that individual analyses within a bore showed irregular fluctuations, tending to mask the general trend in composition change. This was particularly so for the moisture content, which had been determined for 10 ft. lengths of core, whereas the other components were determined for 50 ft. lengths of core. Averaging of the moisture contents over 50 ft. lengths reduced the masking effects of these irregularities. The suggestion was made that these irregularities arose from variations in the relative proportions of pollen, resin, wood (lignite) and woody attritus composing the core. Such variation in the coal seams has since been established in some detail for the...

Jan 1, 1948

By G. J. Borbely, E. A. Devuyst, V. A. Ettel

Introduction Of the techniques reported for cyanide removal from effluents, alkaline chlorination is the most common (Fisher and Wasser, 1969; Reidt, 1969). Shortcomings with this technique are the high reagent costs, chlorine contamination, and potential formation of cyanogen chloride. Chemical oxidation methods are also not suitable to remove cyanide from effluents containing sulphides in suspension, such as flotation tailings. An inexpensive method for removing cyanide, combined cyanide and related species from waste waters has been developed in Inco laboratories. The method is based on the use of sulfur dioxide (or a sulfite), lime, and air as the reagents. The decomposition reactions of cyanide, combined cyanide, and related species are catalyzed by copper in solution. Complete removal of cyanide species, most of which are oxidized to cyanate, is obtained by treating copper containing cyanide effluents with sulfur dioxide-air mistures while maintaining the pH between 6 and 10 with addition of lime. The new approach can also be applied to selective destruction of cyanide and combined cyanide in effluents containing sulphides in suspension, such as pyrrhotite. Again, a sufficient amount of dissolved copper must be present or added. Metals and precious metals present in the effluents are recovered as hydroxides by adjusting the pH of the treated effluents to about 9-10. Using the new method, the anionic species are removed in the following order: Free CN- > Complex CN- > Thiocyanate The above removal sequence is unusual as oxidants such as chlorine and ozone oxidize thiocyanate preferentially over the combined cyanide.

Jan 1, 1985