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By Thomas M. Barczak

This US. Bureau of Mines report examines the roof and floor contact pressure provided by the interaction of a shield with the surrounding strata. Controlled forces were applied to an 800-ton two-leg shield in the Bureau's mine roof simulator; the distribution of forces acting on the canopy and base of the shield were measured with 24 hydraulic pressure cells. Several influential factors that affect the load distribution were investigated: (1) the magnitude of loading (leg pressure); (2) the profile of the canopy, principally the upward-sloping tip; (3) the base-lifting device; (4) horizontal load acting on the shield; and (5) compliancy of the immediate roof and floor. It was concluded that the shield does not develop full canopy or base contact without deformation of the strata. Maximum contact pressures are developed at the rear of the canopy and on the toes of the base. Less than 10 pct of the available shield capacity is developed at the canopy tip despite the design intention to ensure tip contact. Horizontal loading reduced the toe pressure acting on the base by as much as 75 pct. The base-lifting device exaggerated the inherently high toe loading, increasing the contact pressure by more than 200 pct.

Jan 1, 2010

By J. P. Harrison, J. A. Hudson.

ABSTRACT: When considering the rock stress component of rock mechanics design, the basic procedure is to consider the pre-existing stress-state in the rock mass and then estimate the disturbance to this stress state as a result of engineering excavation. Failure criteria are applied to the final stress state to establish whether failure will occur. However, during the evolution of the stress state, the failure locus may be reached before the anticipated failure state and, in this case, failure will occur unexpectedly. This indicates that the complete stress path (defined as the variations in magnitudes and orientations of the stress tensor components resulting from engineering-induced or natural changes) must be considered. We list a set of stress path principles with their corollaries and then introduce a new and powerful method for simultaneously illustrating changes in the six independent components of the stress tensor. This method plots the magnitudes of the principal stresses above their orientational paths on the hemispherical projection, to provide a three-dimensional stress path locus for each of the three principal stress components. In connection with this presentational device, we illustrate a number of concepts associated with the stress path in rock engineering. For example, we show how the minor principal stress approaches zero at an unsupported excavation face, the interchange of the trajectories of two principal stresses when their magnitudes become equal, and the influence of the bounds on the principal stresses given by strength criteria. RESUME: Si on s’interesse à la composante “contrainte” lors d’un dimensionnement en mécanique des roches, la méthode de base consiste à considérer l’état de contrainte pré-existant dans le massif rocheux, puis d’estimer la perturbation à cet état générée par l’excavation projetée. Des critères de rupture sont appliqués à l’état de contrainte final pour établir si une rupture va se produire. Cependant, lors de l’évolution de l’état de contrainte, la surface critique peut être atteinte ce qui provoquera une rupture anticipée et, dans ce cas, cette dernière sera inattendue. Cela indique que le chemin de contrainte complet (défini par les variations de l’intensité et de l’orientation des composantes du tenseur des contraintes liées à des causes anthropiques ou naturelles) doit être pris en compte. Nous présentons un ensemble de règles pour les chemins de contraintes ainsi que leurs corollaires et, ensuite, nous introduisons une méthode, nouvelle et puissante, pour présenter simultannement les changements des six composantes du tenseur des contraintes. Cette méthode consiste à tracer l’intensité des contraintes principales sur le chemin d’orientation des contraintes à l’aide d’une projection hémisphérique afin d’obtenir le lieu, en trois dimensions, de chaque contrainte principale. En relation avec cet outil de représentation, nous illustrons certains concepts associés au chemin de contrainte en ingénierie au rocher. Par exemple, nous montrons comment la contrainte mineure tend vers zero à la surface d’une excavation sans soutenement, le changement de direction des deux contraintes principales quand leur intensité deviennent égales, et l’influence des conditions aux limites sur les contraintes fournies par un critère de rupture. ZUSAMMENFASSUNG: Bei ingenieurmassigen Taetigkeiten in Felsgesteinen ist es noetig die ungestoerten Gesteins Stress Componenten, die vor einem anthropogen Eingriff im Gestein vorhanden waren, zu kennen und erst dann Vorhersagen ueber Stoerung des Stress Zustandes, der durch einen ingenieurmaessigen Eingriff hervorgerufen wird, herzuleiten. Kriterien fuer das Versagen werden im letzten Stadium, des Stress Zustandes angewendet, um zu erfahren ob ein Versagen wohl eintreten wird. Es ist jedoch zu beachten, dass waehrend des Stress Aufbaus ein oertliches Versagen eintreten kann, welches vor dem eigentlichen, erwarteten Versagens Zustand auftritt. Diese Moeglichkeit weist darauf hin, dass der gesammte “Stress Path” (definiert durch die Variationen der Stress Tensor Komponenten in Richtung und Groesse, hervorgerufen durch ingenieurmaessig hervorgerufene oder natuerlich Vorgaenge) betrachtet werden muss. Wir fuehren eine Liste der “Stress Path” Prinzipien auf und stellen dann eine neue und wirksame Methode zur gleichzeitigen Darstellung der sechs unabhaegigen Komponenten des Stress Tensors vor. Diese Methode stellt die Groesse der “Principal Stresses” in Abhaengigkeit von ihrem rauemlichen Weg auf einer hemispherischen Projektion dar und erlaubt hiermit eine drei dimensionale Darstellung fuer jeden Ort des “Stress Path’s” in die drei Haupt Stress Komponenten. Im Zusammenhang mit der hier gegebenen Darstellungsart, verdeutlichen wir eine Reihe von Konzepten in der Felsmechanik. Wir zeigen zum Beispiel, wie der “Minor Principal Stress” Null zustrebt an einer Wand von einer nicht abgestuetzten Ausschachtung, den Austausch von Trajektorien zweier “Principal Stresses” wenn ihre Groessen sich gleichen, und den Einfluss der Groesse von “Principal Stresses” bei gegebenen Kriterien des Festgkeits Versagens.

Jan 1, 2003

By V Cullinan, D Buchanan

The Brunswick plant is located in Costerfield, approximately 40km east of Bendigo in central Victoria. Crushing, grinding, gravity gold concentration and flotation methods are used to produce a saleable gold concentrate and an antimony-gold flotation concentrate. This paper discusses the improvements made within the processing plant which have resulted in a 99% increase in throughput over nameplate capacity of 6 250 average tonnes per month to 12 445 average tonnes per month and increases of 12% gold (from 2007 average of 78% to 2014 average of 90%) and 16% antimony recovery (from 2007 average of 79% to 2015 average of 95%). This combined effort has resulted in an increase of equivalent gold ounces (AuEq oz) produced from 2010-2014 of 15 872 to 82 574 – a 66 702 increase.AuEq oz= Au oz +Sb t × Sb (US$/t)Au (US$/oz)CITATION:Buchanan, D and Cullinan, V, 2015. Improvements in bi-metal production at the Brunswick Plant, Costerfield, in Proceedings MetPlant 2015, pp 267–272 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

By L. B. McConville

The general term "tar sand" refers to sand that contains varying amounts of dense, viscous petroleum. Tar sand deposits have been found throughout the world, often in the same geographical area as conventional petroleum. The largest one by far is known as the Athabasca Tar Sands, in the province of Alberta, Canada. Actually a group of three deposits, these particular sands underlie an aggregate area of more than 12,000 sq miles. Current estimates place the contained raw petroleum at about 700 billion bbl; and via currently available technology, the amount of recoverable synthetic oil may be as much as 300 billion bbl-which is roughly equivalent to five times the combined US and Canadian total crude oil reserves. With the ever-widening gap between energy supply and demand, mining and petroleum companies are now evaluating all possible energy resources-both developed and underdeveloped-and, certainly, the Athabasca Tar Sand deposit is one of the more important ones to merit such attention. The first section in ME deals with the geology and historical developments; the other four sections, with mining methods, extraction technology, economics, and outlook.

Jan 1, 1975

By R. W. Raymond

I DESIRE to call the attention of the Institute briefly, and by no means in the way of an exhaustive description, to the interesting developments recently made on the east bank of the Hudson River, in the mining of spathic iron ores. The mines to which I refer are those of the Hudson River Spathic Iron Ore Company, situated at Oakhill on Hudson, Columbia County, N. Y., five or six miles from the city of Hudson, and opposite the town of Catskill. The ore occurs in beds, constituting apparently members of the stratified series of rocks on that side of the river, coursing nearly north and south, parallel with the river, and dipping east. The principal out- crops are presented in a range of low hills, about one mile from the river, along the crest, on the western face of which the stratum of spathic ore is more or less exposed. The length of the line in this range, along which, at various openings the ore has been discovered in profitable quantity, is about two miles. To the northward, the hills are somewhat higher, and the stratification may possibly be disturbed, though the rapid examination of the locality which I made in November last did not, include any determination of this

Jan 1, 1876

By Fred Perea

The practical example of the effectiveness and necessity of establishing and maintaining close communications between the design engineering section and operating section of a large plant concerned with the building of an underground crusher will be presented.

Jan 1, 1969

The Kwademen Au deposit was discovered in 1977- 1978 following a regional geochemical survey carried out as part of a UNDP (United Nations Development Programme) and BUMIGEB (Bureau des Mines et de la Geologie du Burkina) mineral exploration programme. The climate in Burkina Faso is rather dry, with markedly seasonal rainfall averaging 800 mm pa in the Kwademen project area. The relief is low and the drainage poorly developed, so that soil sampling was preferred to stream sediment sampling. Rocks have been subjected to deep lateritic weathering, so that they are transformed into a mixture of Fe-oxides and kaolinite over depths varying between 30 and 40 m. At the regional stage, soil samples (30-40 cm depth) were collected a a 300 x 500 m grid. The Kwademen deposit was indicated by Cu, Zn, Mo and Au anomalies. Subsequently, an area of 9.2 km2 was covered by a detailed geochemical survey by soil (100 x 50 m) and auger sampling. The regional anomaly was fully confirmed, and subsequent drilling intersected mineralized ore shoots, justifying the establishment of an evaluation project led by the U.N.R.F. (United Nations Revolving Fund) in 1983- 1985.

Jan 1, 1988

A diverse selection of rockbolt designs and resin anchors are available for use in underground mines. Research in recent years at the UNSW Mining Research Centre led to the construction of a rockbolt pull-testing facility. This facility has subsequently been upgraded, commissioned and initial test work has been completed to verify the pull-test process. A test program has been completed with the objective to understand the load transfer mechanism and improve the general performance of rockbolts. This paper describes the results of this research. Une sélection diverse de dessins du rockbolt et ancres de la résine est disponible pour usage dans les mines de métro. Faites des recherches ces dernières années à l'UNSW que le Centre de la Recherche Minier a mené à la construction d'une facilité de l'essai de la traction du rockbolt. Cette facilité a été améliorée par la suite, le travail de l'épreuve en commission et initial a été complété pour vérifier le processus de la traction-épreuve. Un programme de l'épreuve a été complété avec l'objectif comprendre le mécanisme du transfert de la charge et améliorer la performance générale de rockbolts. Ce papier décrit les résultats de cette recherche. Eine verschiedenartige Auswahl an rockbolt-Designs und Harzankern ist dafür verfügbar, benutzen Sie in unterirdischen Bergwerken. Forschung in letzten Jahren beim UNSW-Bergbau Forschung Zentrum führte Ruckerprobung-Einrichtung zur Konstruktion eines rockbolt. Diese Einrichtung ist anschließend befördert worden, ist beauftragt worden und wird abgezeichnet, prüfen Sie, die Arbeit ist vervollständigt worden, um den Ruckprüfung-Prozeß zu verifizieren. Ein Prüfungsprogramm ist mit dem Objektiv vervollständigt worden, den Lastübertragungsmechanismus zu verstehen und die allgemeine Aufführung von rockbolts zu verbessern. Dieses Papier beschreibt die Ergebnisse dieser Forschung.

Jan 1, 2003

This paper describes new research and development currently being undertaken by the CSIRO Mining Technology Group to advance the automation capability of continuous mining equipment in underground coal mining operations. The effort aims at increasing the overall rate of roadway development as well as providing a safer working environment for underground mine personnel. The activity is funded by the Australian Coal Association Research Program (ACARP) and forms part of a larger underground development initiative, known as the CM2010 project. The CM2010 is managed via a consortium of leading mining industry representatives through the Roadway Development Task Group (RDTG). The Task Group has identified three research areas requiring new development in order to realise the CM2010 project objectives: self-guiding (autonomous) continuous miner capability, an enhanced drilling and bolting process and improved mesh deployment. CSIRO's primary role in the CM2010 project is in the development of the autonomous continuous miner guidance capability.This paper reports on outcomes achieved at the half-way mark of a three year research and development project. It details the technical developments undertaken towards demonstration of a 'self-steering' capability to enable a continuous miner to automatically maintain a given mining heading and mining horizon under production conditions. A primary technical requirement of this automated functionality is the means to accurately determine both the location and orientation of the continuous miner in real-time. Testing and validation of the guidance system solution has been implemented using a combination of an instrumentation-grade inertial navigation unit and radar technology. Comprehensive performance evaluations have been conducted using a scale skid-steer mobility platform known as the Phoenix. Results achieved to the present stage of the project are highly promising and suggest that an automated self-steering functionality is achievable under production conditions. This new outcome represents an important move towards implementing a step change improvement for future underground roadway development.

Dec 6, 2010

By V. Panayotov, M. Panayotova, R. Villas-Bôas

The "United Nations Framework Classification (UNFC-2009) for Fossil Energy and Mineral Resources 2009” is the international system designed to meet (to the extent possible) the needs and to support the decision making and resources management of private industry investment, governments, policymakers, bank investment, scientists. There are different international and national systems classifying commodities (resources, reserves, possibility and feasibility to extract them, etc.) with their own definitions and reporting terminology which often do not overlap entirely or even differ significantly - thus creating difficulties and problems among stakeholders to understand each other. The UNFC-2009 is developed to allow “speaking in one language”. The paper presents briefly the UNFC-2009. The UNFC-2009 applies simultaneously three fundamental criteria to classify projects: economic and social viability, field project status and feasibility, and geological knowledge (so called E, F and G axes), thus creating a visualized, easily understandable three dimensional system. The E, F and G axis categories are divided to subcategories, using additional criteria. The UNFC-2009 is already applicable to solid minerals, nuclear fuel resources, petroleum. The amounts of solid waste generated by metals production from ores (mining, minerals beneficiation, extraction metallurgy) and its metals content are discussed from the viewpoint of using the waste as resource. An attempt is made to apply the UNFC-2009 to technogenic waste from metals production from ores - both to old engineering constructions (historic mining dumps and reclaimed beneficiation tailings ponds) and new (currently in use) dumps and ponds.

Jan 1, 2016

By Arnulf Muan, Hobart M. Kraner

Ferromanganese alloys react with aluminu-silica brick in blast furnace hearths and cause the formation of new phases with low refractoriness and consequent failure of the refractory lining. The nature of these reactions is explained on the basis of petrographic observations, thermodynamic data, and Phase equilibrium considerations. Animproued hearth design resulted from these findings. The production of ferromanganese in blast furnaces presents many problems which are not encountered in the production of iron in the same furnaces. One of the most serious of these problems is the rapid failure of refractories caused by their reaction with the ferromanganese metal. The present paper describes such a "hearth attack", its symptoms, causes, and cure. Following an introductory discussion of operating practice in ferromanganese blast furnaces, results are presented of a petrographic examination of samples from a furnace which had to be shut down because of refractory failure. The causes of this failure are then analyzed on the basis of petrographic observations combined with thermodynamic and phase equilibrium data available in the literature. The latter type of data were subsequently used as a guide in recommending improvements in hearth designs which have since proven themselves successful in practical operations. I) FERROMANGANESE BLAST FURNACE PRACTICE It is considered good practice to blow in a furnace on iron and operate it in this way for a period of time preliminary to producing ferrornanganese. During this time, iron generally penetrates the bottom refractories six or more feet below the original working surface of the hearth. Not only does this metal pervade the joints to these depths, but the pores of the refractories are usually also filled by molten iron. The high throughput of the iron furnace provides ample heat to maintain a high temperature in the hearth refractories. This, together with a high ferrostatic pressure, causes porous clay brick of the hearth to shrink. During subsequent use of such a furnace in ferromanganese production, the iron in the pores of hearth brick if; replaced to some extent by ferromanganese. The replacement is usually not complete. This is probably due to the lower metal throughput and lower prevailing temperatures resulting from this in the brick of the hearth bottom. When the ferrornanganese furnace is banked—or when the temperature in the furnace falls due to a furnace delay—-manganese oxidizes even though the atmosphere is largely CO. Considerable expansion accompanies this oxidation of manganese from metal to oxide. The hearth refractories are then subjected to the disintegrating forces of the volume expansion. These forces may in extreme cases be large enough to lift the furnace off its mantle supports as was described in a previous paper.' When cooling takes place slowly, however, and the temperature remains at a fairly high level, the refractories undergo fluxing action by the MnO. This latter reaction and the reduction of SiO2 of the clay brick is the general subject of the present paper. The observations to be described herein were made on a ferromanganese furnace located at the Johnstown plant of Bethlehem Steel Co. The furnace was lined entirely with clay refractories and had operated on iron for 266 days and on ferromanganese for 96 days prior to being taken off because of a hearth wall failure. II) PETROGRAPHIC EXAMINATION AND CHEMICAL ANALYSIS The photograph reproduced in Fig. 1 shws a cross section of the upper part of an 18 by 9 by 4-1/2 in. bottom block removed from the blast furnace. This brick came from a depth of approximately 6 ft below the original working face of the bottom. It will be noted that the 4-1/2 in. dimension is almost the same as when the brick entered the furnace. Three characteristically different zones marked I, II, and III on the print of Fig. 1 are apparent. Results of chemical analyses of the original brick and samples from each of these zones are listed in Table I. Petrographically the various zones were characterized as follows: The central zone marked I was essentially un-reacted brick. The microstructure consisted of fine needles of mullite, and the pores in this entire area were filled with iron. This is characteristic of

Jan 1, 1962

By Joe E. Bryan, John P. McDonnell

"Underground mine rib stability is an ongoing safety issue in all mining applications. Rib-related accidents present at least as many problems as roof-related ground control. Underground coal mine rib safety is continually emphasized as a primary safety concern at every mining operation. The application of rib support materials is increasing as more difficult mining conditions are experienced due to deeper cover, more variable depositional environments, thicker seam heights, and multi-seam mining effects. As the coal seams become thicker, the need for rib control increases. A variety of rib control methodologies has been documented and research continues on mine design methods and support techniques to reduce or eliminate rib-related accidents.This paper presents an alternative rib bolting technology using proven conventional rib support systems that allows mine personnel to more efficiently install rib support during development operations. This alternative rib bolting method allows for additional rib support with a single support installation.INTRODUCTIONRib control continues to garner the watchful eye of both concerned operators and government officials due to many factors: inherent safety within entries and crosscuts, actual rib stability history, safety improvement, cost control, improved mining methods, and maintaining production goals. As demonstrated through many years of actual practice, desired outcomes can be achieved by scrutiny, innovation, and combining improved practice methodologies.Rib surface control continues to be a necessary part of the production process. However, production and safety issues persist at the point of installation using current control apparatuses and methods to install rib controls. Among others, current issues of rib control are quantity of bolts required, overall time required for installation, ease of apparatus installation, flexibility of the system for appendage installation and operator exposure. A need exists to decrease the time miners spend installing rib control apparatuses, while increasing the safety of such installation processes. At present, installing rib control devices (primary rib bolts, plates, mesh, and, in most cases, secondary rib bolts and plates) is performed in a very congested area and is time-consuming process at the primary coal-winning area: the face. The MatLok system addresses these problems."

Jan 1, 2015

By S Jephcott

The McArthur lead-zinc-silver deposit is of the stratiform type. It consists of a mineralised bituminous shale sequence containing some tuffites, numerous graded beds and isolated slump breccia horizons. The principal sulfides; pyrite, sphalerite and galena, are essentially restricted to the shales and the genetically unrelated turbidites contain only minor mineralisation. The geochemistry of the deposit has been investigated with respect to the stratigraphic column and mineralogy of the sediments. A sedimentary origin is advocated for the deposit. Volcanism, thermal spring activity and high salinities, perhaps related to the Emu Fault, are considered as contributing factors to ore genesis. The metallurgy of this deposit is discussed in relation to its geologic history.

Jan 1, 1971

By C. A. Fleming, K. W. Sarbutt, P. K. MacPhail

The SART process has been developed for Teck to treat bar­ren solution from the cyanidation/CIP process that has been developed for the Lobo-Marte project in Chile. The objective of the process is to recover cyanide in a form that is suitable for recycling to the leaching part of the process. The Marte and Lobo ore bodies require a dosage rate of about 2 kg/t NaCN, of which only 0.5 kg/t is truly consumed (as thiocyanate, cyanate and ferrocyanide species). The remaining -1.5 kg/t is present as cop­per cyanide (-1 kg/t) and free cyanide (-0.5 kg/t), and is poten­tially recoverable and recyclable. SART is an acronym that describes the unit operations in this cyanide recovery process; namely, .. Sulphidization .. Acidification .. Recycling of precipitate " Thickening of precipitate The basic chemistry has been applied previously, and has also been the subject of two patents (American Cyanamid Company, 1965, Potter et al., 1986). The process involves the conversion of all free and WAD cyanide in solution to hydrocyanic acid by acidification of the tailings solution to pH :s,4, and the conversion of all copper in solution to cuprous sulphide (synthetic chal­cocite) by the addition of a sulphide salt:

Jan 1, 1998

By J. R. Hurley

The continuous flow, horizontal drum blender has dynamic properties which may be described by the same type of equations which often arise in electrical filter analysis. Furthermore, the equations may be readily solved by the same techniques used in electrical control analysis. For this reason the blender model developed is termed an "Electric Analog", although strictly speaking it is a mathematical model. Presentation of the dynamic performance of the blender as an electrical (or mathematical) model is desirable for several reasons. The model can be of assistance in correlating performance data with equipment design parameters. The model 'can be used with other process equipment models for simulation of an entire plant operation or in stability studies. In addition, the model may be useful in providing insight into the actual blending mechanism, or it may suggest a similar method of analysis for other closely allied equipment.

Jan 1, 1967

By François G. Bernardeau

Cement-bentonite (C-B) slurry walls have been used for ground water cutoff in deep excavations, contamination containment, and other applications. Hydraulic conductivity is of great concern for cement-bentonite slurry walls. The quality control program usually specifies permeability and strength tests to be performed in a laboratory on samples cast in the field and cured for a certain time. Currently there is no widely accepted in-situ test method for the performance of the constructed slurry wall. A recently constructed cement-bentonite slurry wall in South Carolina included a 200-foot-long test section done in advance of the production of an 8,300 foot-long wall. Intensive tests and investigation were conducted during and after the test section construction: Monitoring piezometers were installed using wet insertion method and packer tests were conducted in boreholes drilled in the post-28-day-cure slurry wall. The permeability measured from the packer tests was about two orders of magnitude higher than the design and the laboratory test values. Additional investigation was performed using a video camera to inspect the borehole walls especially the packer test sections. Test pits were excavated to observe both sides of the cement-bentonite slurry wall. A thorough inspection was conducted to evaluate the integrity of the wall. The lessons learned and issues regarding the disturbance effects of in-situ testing of cement bentonite slurry walls is presented and discussed.

Jan 1, 2008

By E. E. Wark, J. Rogers, I. W. Wark, K. L. Sutherland

SOAPS have been used as collectors for many years, but only in the last eight years have other long-chain paraffin salts been used. It may be anticipated that these newer collectors will be used mainly with nonsulphide minerals, for which the xanthates and similar compounds are of little value. On the other hand, the xanthates are both cheap and effective for sulphide ores and seem likely to retain their present eminence in this field. During 1938 and 1939 two of us (E. E. W. and I. W. W.) commenced a comprehensive investigation of the principles underlying the use of paraffin chain salts as flotation reagents. This research was sponsored jointly by the University of Melbourne and a group of Australian mining companies.[t] A broad, semi quantitative survey was then made of the field covered in the present paper. This was followed in 1940 by further work by one of us (K. L. S.). In 1941 the investigation was taken over by the Division of Industrial Chemistry of the Commonwealth Council for Scientific and Industrial Research, Australia. Discovery of some principles upon which are based the flotation of minerals by paraffin chain salts was followed by their application in the development of processes for the recovery of certain strategic minerals from their ores. Promising results in the flotation of cassiterite from various ores will be described in a subsequent paper. THE PARAFFIN CHAIN SALTS The basic requirements for a "collector" in flotation are that it should form a film over the surface of the mineral to be floated, and that this film should be orientated so that hydrocarbon (nonpolar) groups form the effective surface. When modified in this way, the mineral surface possesses some degree of air avidity. All investigators would agree with Taggart, Taylor and Ince23 that such a film can be produced only if the collector compound contains an active (polar) group to attract it to the mineral surface as well as the nonpolar group. One section of this large class of polarnonpolar compounds is the paraffin chain salts: CH3(CH2) „X where X signifies a polar group that ionizes in aqueous solution. Though the compound can ionize, it may be a weak or a strong electrolyte, and the hydrocarbon chain may be in the cation or the anion (Table I). Many compounds of similar constitution are available, but the usual polar groups are: -CO2Na, -SO3Na, -SO4Na, - PO4Na2, or an aminonitrogen group, the

Jan 1, 1946

By Guillaume Blanc

The development of marine mining in the offshore areas adjacent to most of the insular and continental European States is limited by the complex and evolving nature of its legal regime on the basis of the relevant applicable international, European and domestic rules. As the development of marine mining requires investments in capital-intensive technologies, the bankable feasibility of marine mining projects is very much dependent on the legal security of mining rights, assets and operations in offshore areas. This is quite difficult to assess due to the constant accumulation of applicable and potentially conflicting international and domestic laws in these areas, in particular the coastal zone, the territorial sea, and the Exclusive Economic Zone (EEZ). The often conflicting interaction of international treaties, laws and regulations in offshore areas raises specific and major issues in terms of permitting processes, access rights, ownership rights over the mineral resources explored and mined, flag vs. coastal State jurisdiction over mining vessels and marine mining equipment, international environmental liabilities, and unitisation and multi-forum disputes. In addition, the determination of jurisdiction and the legal regime under which marine mining could take place is becoming even more complex with the development of EU Law and the recent revision of the International Law of the Sea, particularly the new extension regime of the EEZ and jurisdiction over the continental shelf.

Jan 1, 2004

By Joseph B. Umpleby

WHEN the Cushing field flooded the oil market in 1914 and 1915 with a daily output equal to nearly one-third of the world's production, the situation was soon corrected by increased consumption, and the price of crude oil rose from 45 c. per barrel in, February 1915 to $1.10 in December of the same year-the highest price paid in the Mid-Continent field up to that time. The intensive search for oil during the following seven years failed to disclose a single new ,field equal to Cushing, and many observers concluded that the rapidly increasing number of wells contributing to the world's output, each declining roughly 20 per cent. a year, combined with the rapidly increasing con¬sumption of petroleum, made it highly improbable that any field would; be found again sufficiently large to seri¬ously affect the oil market. That seven exceptional fields should then be discovered simultaneously is a remarkable coincidence. Long Beach, Santa Fe Springs, and Powell, each exceeded Cushing in daily output and reached the apex of their production during a year when Burbank, Tonkawa, - Smackover and Huntington Beach each contributed several times the daily output of the average new pool. This unexpected and tremendous flood of flush production could only have the effect of depressing price and greatly adding to stocks throughout the country. It was particularly depressing in the Mid-Continent as the new oil from California proved of attractive refining grade and because of cheap transportation by water easily undersold Oklahoma crude in the eastern markets.

Jan 1, 1924

By M. M. Rao, P. G. Winchell, R. J. Russell

A detailed analysis has been used to correlate the avalable thermodynami c da In on iron-ric11 Fe-Ni (41loys in the body-centered a, and the face-centered y phases. The inp ut injovrt~ation required by the a am lysis consists of tile heat of the a, to y transformation at 1123°K, the heat of mixing of y at 1123°K, tile specific heats of both a, and y (decomposed into Debye, electronic, and magnelic contributions), and the positional and magnetic entropies of both a, and y. PYLrrzary oirt.bul of the analysis is the free energy of each phase as a Junction of temperature and composition. FOr Fe-Ni alloys the adjustment of twenty-one parunletevs allows the accurate reproduction of enthalpy data for both phases, the heat of mixing- for y, the a/y equilibrinm compositions in the Fe-Ni phase diagram, and the usually accepted enthalpy and entropy of a and y iron. Also obtaitzed are fuirly accurate reproductions of electronic specific heat coefficients predicted from electron- to-atom ratio interpolations and To temperatuves eslimanted from transformation studies. Also considered in the calculation are the elastic constants, Curie temperatures, saturation magnlelizalion values, and indications of short- range order. The measnred activity coefficient of iron in anstetnite could not be accurately matched. The major source of uncertainty in the model is thought to be the magnetic contribution to the entropy of austenite. Calcrclations were extended to Fe-ni-C alloys using available carbon-acliuity data. The free energy of transformation from martensile to r at fixed composition was obtained as a function of nickel and carbon contetzt, and binary thetal-carbon phase diagrams Were estimaled as a function of nickel contenl. We needed thermodynamic information for Fe-Ni and Fe-Ni-C alloys at temperatures between 400" and 800°K in order to interpret the results of several phase-transformation studies. The most recent theoretical analysis of the thermodynamics of Fe-Nialloysl was based on a lumped-parameter, regular-solution model and used the Fe-Ni phase diagram available at that time.' Because significant difficulties were encountered in attempting to extend this analysis to Fe-Ni-C alloys, and because more experimental data has become available recently, we decided to attempt a new correlation. The analysis used here allows the extrapolation of measured and calculated thermodynamic values to lower temperatures and the extension of the thermodynamic analysis to Fe-Ni-C alloys. The structure of this correlation consists of expressions containing a total of twenty-one adjustable parameters. The forms of these expressions are discussed in the next section; however, a less formal summary is presented now to provide a physical overview of the model and to indicate its connections to prior work. Primary input information for this correlation is described below. The measured values of the specific heat of iron3 and its analysis475 and theoretical estimates of the specific heat of y* iron at low tempera- loys at 1123°K has been measured by solution calori-metry.7 The enthalpies of both a, and y have been measured most recently by Scheil and Saftig,B who used a dry-ice calorimeter. These data are used to formulate expressions for the heat of mixing of y and the heat of transformation of a, to y both at 1123°K. The a and y solubility limits in the Fe-Ni phase diagram have been redetermined recently9 by methods which assure a close approach to equilibrium. The a to y transformation can occur without change in nickel content or free energy at a temperature called TO; TO temperatures for various nickel contents have been estimated from transformation studies. The computed free-energy functions are adjusted by means of the parameters to fit both the phase diagram and the TO temperatures. Primary emphasis is placed on the phase diagram fit. Iron activities have been measured in Fe-Ni austenite10 between 973" and 1173°K. These activity data, which cannot be fitted accurately with our model, indicate that iron is substantially ideal in iron-rich austenite. Secondary, but helpful, information for the present correlation is provided by neutron diffraction and saturation magnetization measurements on both body-centered and face-centered Fe-Ni alloys."-'3 These results were interpreted11 in terms of composition-insensitive, localized magnetic moments on both iron

Jan 1, 1968