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By R. G. McLusky

This paper analyzes the opinion in Bragg v. Robertson, 72 F.Supp. 2d 642 (S.D. W.Va. 1999), a case which threatens the future of surface mining in West Virginia and which will almost certainly result in new policies or rules that will affect surface mining everywhere. This paper addresses: (1) the jurisdictional bases of the action which relies on the federal surface mining laws to enforce a state mining program; (2) settlement agreements reached in the case that threaten to alter federal policies beyond West Virginia borders; (3) a programmatic environmental impact statement on mountaintop mining being undertaken by the federal government; and (4) an opinion by the Court outlawing excess spoil disposal in intermittent and perennial streams.

Jan 1, 2001

By R. Gibala

Internal-friction measurements on hydrogen-charged iron over the temperature range 4° to 300°K are reported. Two relaxation peaks, the hydrogen Snoek peak at 48 °K and the hydrogen cold-work peak in the range 145" to 2200K, are observed at 80 kc per sec. The effects of hydrogen-charging, aging, and deformation on the internal-friction results are determined and are used to show evidence of partitioning of hydrogen between solid solution and dislocations. The hydrogen-dislocation binding energy is estimated from the behaviors of the relaxation tiwzes and relaxation strengths of the Snoek peak and the cold-work peak. Its value is approxi,mately 6400 cal per mole. MANY investigators have demonstrated the usefulness of internal-friction measurements in determining the manner in which interstitial impurities interact with dislocations in bcc metals. Part of this success has resulted from the existence in bcc interstitial alloys of two anelastic relaxation peaks—the Snoek peak' and the cold-work or Koster peak2 (designated hereafter by SP and CWP, respectively). The SP has its origin in the redistribution of interstitials in solid solution among sites made energetically nonequivalent by an applied stress. The rate at which the redistribution occurs, measured by the relaxation time for the process, is related in a simple way to the diffusion rate of the interstitial in the free solution. The relaxation strength is proportional to the concentration of interstitial in solid solution. The CWP appears to have its origin in the relaxation of an interstitial-dislocation complex for which the relaxation time at a given temperature is much longer than that for the SP. The relaxation strength depends strongly on the concentration of interstitial and the amount of deformation at relatively low concentrations and deformations.2-8 From the dependence of the relaxation strength on interstitial concentration, the SP and CWP may serve as measures of the concentrations of interstitials in free solution and bound at dislocations, respectively. Thus their behaviors have been used to investigate interstitial-dislocation interactions in Fe-C, Fe-N, and several refractory metal systems.'-' However, the Fe-H system has not been studied extensively,? even though disputes in recent years over the mechanism of hydrogen embrittlement in steels involve argument over the extent to which lattice hydrogen and hydrogen-dislocation interactions play an important role.?-'' Previous work on Fe-H indicates the internal-friction behavior to be qualitatively consistent with that for other systems. Apparently, both a SP and a CWP are observed in the temperature ranges 30" to 50°K and 100°to 140°K, respectively (at 1 cps). However, there is neither sufficient nor accurate enough information to identify convincingly these peaks with their supposed counterparts in other systems. Nor have there been any attempts to make quantitative use of these peaks to study hydrogen diffusion, aging, or interaction processes. In this paper, an attempt is made to obtain more complete information on internal friction of hydrogen in iron than presently available. Internal-friction measurements in the range 4° to 300°K on hydrogen-charged iron show that the two peaks discussed above are in fact the hydrogen SP and CWP. Several effects of hydrogen charging, aging, and deformation on these peaks are observed and are used to determine the partitioning of hydrogen between solid solution and dislocation sites in iron. EXPERIMENTAL Materials. The starting material for this investigation was a high-purity iron supplied by National Research Corp. as a 1-in.-diam rod. The following analysis was given (inwt pct): C, 0.004; N, 0.0003; 0, 0.007; P, 0.002; S, 0.005; Si, 0.006; Mn, 0.001; Cu, 0.002; Ni, 0.005; Cr, 0.001; Mo, 0.001. After an initial vacuum anneal (-5 XTorr) at 700°C, the rod was cold-

Jan 1, 1968

By N. Powell, R. J. Pine

An algorithm is proposed for updating the probability of slope failure on the basis of sequential testing using Bayesian probability theory. The approach is novel and computationally straightforward since, unlike other methods, updating of the probability of failure is carried out directly. This is because the probability is treated as a random variable whereas other methods have considered it as a purely deterministic value or as a function of shear strength parameters that are updated individually. The prior information required for the Bayesian analysis is obtained by a conventional probabilistic analysis. An exponential distribution is then used for the probability of failure, applying the principle of maximum entropy. This distribution is continually updated for individual slope cells, where repetitive excavation creates several such cells and a corresponding series of Bayesian estimates of the probability of failure is obtained. The approach is applicable to most simulations but there are limitations on its use. A more mathematically rigorous refinement using the beta distribution is currently under development

Apr 1, 1996

By A. W. H. Morris, E. A. Steigerwald

The jatzgue beizazriov oj Mietal matrix co))zpos~tes in tension -lensiom loading has been imestigated as a junction of Dolume fraclion veinfovcelnent using the model systems of a silver matrix reinforced with contlnuous or dzscontztinuous aligned tungsten jilamenls and continuous aligned steel filamenls. Appreciable impvocetnents in fatigue strength were obseved in all syslems inzvesLigated, the degree of sl renglhenng-increasing with increasing volume fraclion of reinforcement. The mode of fatigue failure was found to be a function of colutrre jp-actiotz and was also noted to be controlled by the relative fatigue and strength characlerislics of the matrix and reinforcemenl. THE advantages to be gained by suitably incorporating high-strength filaments or whiskers into metallic matrices are well-recognized.' To date emphasis has been placed on the experimental determination of tensile strengths and elastic moduli of metal matrix composites measured parallel to unidirectionally aligned filaments. Several attempts have been made to relate experimentally measured tensile properties to theoretical values calculated from the properties of the components on the basis of the relatively simple "rule of mixtures" analysis. However, relatively few data have been reported in the literature on the fatigue behavior and mechanism of fatigue failure of metal matrix composites. In a study of fatigue crack propagation in aluminum plus steel wires and aluminum plus tungsten wires, Forsyth et a1.2 found that the incorporation of small numbers of filaments suitably dispersed were capable of substantially reducing the rate of fatigue crack propagation. For this purpose, the strength of the filaments appeared to be more important than the aspect ratio and the authors reported that parallel filaments were not the most favorable orientation for increased strength. In a basic study of the fiber reinforcement of metals, Williams and 0'brien3 report preliminary results which indicate a considerable improvement in fatigue strength in reversed bending fatigue of a steel wire-reinforced aluminum alloy composite. In a study of the influence of interfacial bonding on fatigue behavior, Baker4 has also reported improved fatigue properties in stainless steel-reinforced aluminum composites. In contrast, Ham and place5 report that, although tensile properties are improved greatly by filament reinforcement, the reinforcement of copper with continuous, brittle tungsten wires up to 23 vol pct was comparatively ineffective against fatigue. The authors attribute the poor fatigue properties of the composite to fatigue hardening of the matrix at the tips of cracks which can build up stress concentrations sufficiently large to fracture proximate filaments. Baker and cratchley6 failed to find marked improvements in the reversed-bending fatigue properties of silica-reinforced aluminum. The study was complicated by the complex behavior in a composite during the compres-sive half-cycles imposed in this type of loading. This was manifested in the failure of the composites by de-lamination, a contributing factor being the presence of aluminum oxide at the matrix-filament interface. Prior to the general acceptance of filament-rein-

Jan 1, 1968

By L. W. McKeehan

The occurrence of twins in large ferrite crystals, made by a new process, was reported in a recent note.' This paper describes a typical case of such twinning and suggests, on the basis of the observed facts, why smooth slip-planes are rarely observed in this metal. Method of Preparation The material in which the crystals here dealt with were grown was made from 1/8in. Armco iron welding rod containing C, 0.04; S, 0.037; P, 0.003; Si, 0.008, and Mn, 0.02 per cent. This rod was cold drawn into wire about 1 mm. dia. A piece of this wire was supported vertically and was locally heated in hydrogen at atmospheric pressure to about 1400" C. by an alternating current (60 cycles per sec.) of about 35 amp., passed through it between a pair of traveling contacts about 8 cm. apart. The rate of travel for the case in hand was 12 cm. per hr. After some 30 cm. of the length of the wire had been heated and cooled in this manner the whole wire was immersed for a few seconds in dilute nitric acid, not restrained by alcohol. Etching was continued until, as nearly as could be judged by eye, the original smooth cylindrical surface of the wire was no longer capable of specular reflection. Measurements The wire in the etched state was next mounted in a goniometer of special form which allowed the measurement of the spherical coordinates of the normals to any plane surfaces left by the etching. These coordinates were most conveniently a polar distance, 8, from one direction of the wire axis, and an azimuth or longitude, ?, from an arbitrary prime meridian. The region to be described more particularly is shown at a low magnification in Fig. 1, which gives two different views, differently illuminated to show the spatial relationship of a crystal occupying most of the part shown and of an inclusion, or rather a series of three inclusions suspected of being twins based on the principal crystal.

By Osamu Taki

The innovative Soil-Cement Mixed Wall Technique emerged in Japan and obtained recognition in the engineering and construction communities in the 1980's. This technique was introduced to the United States in 1986. It was accepted as the most credible construction technique by the U.S. Bureau of Reclamation for ground stabilization and cutoff wall work in the Jackson Lake Dam Project, Wyoming in 1987 and 1988. It was also accepted as a remediation technique by U.S. EPA for a Superfund Innovative Technology Evaluation (SITE) demonstration on in-situ solidification/ stabilization. The Soil-Cement Mixed Wall Technique consists of mixing in-place soils with cement grout or other reagent slurries using multiple axis augers and mixing paddles to construct overlapped soil-cement columns. The overlapped column panel is then extended to form an underground continuous soil-cement wall for use as a cutoff wall or a structural diaphragm wall for groundwater control and excavation support. By arranging the column panels in various configurations, the technique becomes a versatile tool for stabilization of soft or liquefiable soils.

Jan 1, 1990

By L. C. IlsLey

"The maintenance of permissible equipment which is tested and inspected at the Pittsburgh Experiment Station of the United States Bureau of Mines is dependent to a surprisng degree upon the voltage at which the equipment is operated. The difficulty of maintaining 500-volt equipment is frequently brought to the bureau's attention, and it is quite possible that if the bureau had appreciated at the beginning the full hazard involved, it would never have undertaken the approval of equipment operating at voltages greater than 250 volts.In this connection, the following statement from State mine inspection departments and other sources are of interest as showing the general feeling in safety organizations with respect to voltages higher than 250. These statements, although obtained as a result of a questionnaire sent cut several years ago, still apply very well to present conditions.A. I have not had time to consider seriously the proposed change from every angle, but looking at it from a standpoint of hazard, feel that the danger would be greatly increased. I have always occupied the position that underground voltage on portable equipment should never exceed 250 volts.High voltage of course would mean smaller transmission lines, which would be more economical and no doubt would require in several instances smaller equipment; notwithstanding, if this statement is true, the writer is still favorable to low voltage on underground portable equipment.B. I believe 500 volts should be the limit on the best equipment ender the best conditions and that the U. S. Bureau of Mines should do all in its power to limit the voltage to 500 volts on permissible equipment, as any increase in voltage means increased hazard.C. I will refer you to a section of our mining law, entitled ""An Act to Regulate the Tine of Electricity in the Mines of the State of ----"" which reads in part, as follows: Trolley wires, or other exposed electrical wires, shall not carry a voltage above 275 volts.You may readily see by this that we are not permitted to operate mining machines under ground in -----, with more than 275 volts at the terminals, except that we are permitted to install transforming stations throughout the mines, after complying with certain regulations at the mine.However, as we have had to date, within the calendar year of 1925, six men electrocuted in the mines of the State, using a voltage of 275 volts, I am of the opinion that if this voltage was increased, the hazard would also be increased in proportion.D. I do not care to make a statement for publication: however, I am referring you to our mining laws. On page 27 and 28 you will find what the laws of -----¬require relative to the installation of electricity in the mines.""Hereafter where electricity is installed no higher than two hundred seventy-five (275) volts shall be used underground, except for transmission, or for application to transformers or other apparata, where the high-voltage circuit is stationary. High-voltage motors, and transformers, shall be installed in suitable chambers, built of fire-proof construction, and well ventilated, and shall not be placed on intake, or between intake and return air courses. All high-voltage lines lines and apparata must be clearly marked, to indicate their danger. Main and distribution switchboards for high voltage shall be made of insulating and incombustible material, such as marble or slate, and to be free of all metallic veins, or of material equivalent thereto. Same shall be installed in a dry place. All switches or other instruments used in connection with high voltage shall be installed on suitable switchboards, with at least a three-foot passageway in front and rear properly floored, and kept looked by a door at each end that can be opened from the inside without a key. With higher than medium voltage, there shall not be any live metal work on the front of switchboard, and the entry circuit must be protected by an oil breaker s"

Apr 1, 1932

By R P. Langford, T A. Moore

Over the last 15 years Indonesia has experienced a surge in coalexploration, which has led to the development of a major export industry. This coal exploration has improved the understanding of the geology of the Indonesian coal deposits. The main economic coal deposits are of Eocene and Miocene to Pliocene age, which mainly occur in Kalimantan and Sumatra and were formed from peat deposits in an equatorial paleoclimate similar to that prevailing today. Some of these peats were domed peats, which grew above the normal water tables, under a climate of year-round rainfall; these peats grew above the level at which waterborne mineral matter can enter the system, resulting in low ash and sulphur, and locally very thick coal. It is believed that such peats have formed the unusually thick, low ash, and low sulphur Miocene coals of Indonesia. Coal deposits of Eocene age are typically characterised by thinner seams, with relatively higher contents of ash and sulphur. The Miocene coals and Eocene coals both appear to have formed in lacustrine, coastal plain or deltaic depositional environments, similar to the modern peat-forming environments of eastern Sumatra and parts of Kalimantan. The Eocene coals formed mainly in extensional tectonic settings. Miocene - Pliocene coal deposits formed in a range of tectonic settings.

Jan 1, 1999

By Curless JM, Power SG

Polymetallic hydrothermal veins of the Western Cascades are hosted in propylitically altered Tertiary volcanics of calc-alkaline affinity and (or) in nearby, altered, and compositionally similar plutons. Ores from shallow and now abandoned mines produced mostly gold and were considered to be of epithermal origin. However, recent discovery of breccia and porphyry types of Cu-Mo mineralisation and other data suggest that the deposits of this terrane vary systematically both regionally, south to north, and locally, high to low altitudes. The evidence includes changes in (1) size, composition, and complexity of plutons, (2) types of mineral deposits; (3) assemblages of alteration and ore minerals; (4) trace metal geochemistry of host rocks; and (5) fluid inclusion and sulphur isotope data. They collectively imply a consanguineous origin of vein, breccia, and disseminated-veinlet types of mineralisation by magmatic hydrothermal processes.

Jan 1, 1987

By Jamel Sgaoula

During 1998 COGEMA Resources Inc. announced that operations at the Cluff Lake mine will be suspended indefinitely by the end of year 2000 as a result of deteriorating uranium market conditions. To remain profitable, Cluff Lake mine started an aggressive cost reduction program. A cost reduction team was formed to look for ways to lower production costs. The focus of this team was to screen all areas and to come up with ideas to improve the economy of the mine and ensure the viability of the operations over the remaining three years of operations. Among the areas where significant savings were achieved are: (1) replacement of portion of cement with fly ash in backfill; (2) backfill optimization; and (3) new shotcrete plant installation on site for bulk in-house shotcrete production. This paper details the research work carried out by Cluff Lake mine on these projects and results of its application.

May 1, 2001

By G. R. Heffernan

"In the early 1970ssteelmakers worldwide were looking forward to many years of expansion and profitability. Huge government investments in Europe, the United Kingdom, Japan, Brazil, and Venezuela were committed in anticipation of growing market s based on long-term OECD forecasts. In 1973 the first OPEC oil shock occurred. Steel demand shrank. Restructuring became the buzz word of the day as billions of dollars in taxpayers' money was poured into eliminating excess capacity and labour. In the United States, where government help was not available, inefficient companies went bankrupt; capacity was cut to 100 million tons from 155 million tons. The industry throughout the industrialized world shrank. By 1979the world economy seemed back on track and a modest degree of optimism could be detected in the international steel fraternity. Then came the second oil shock. By 1982 the industry was in the midst of another shakeout. More bankruptcies, more rationalization, and fewer jobs resulted. In Canada some well-known companies came close to the brink as low prices and high interest rates took their toll. In the light of the turmoil in the steel market over the past 20 years an attempt to forecast the trends through to 2001 is intimidating.However, there are good reasons to be optimistic today about both markets and technology.An economic super power is emerging in western Europe as 1992 draws near. The creation of a single market of 320 million well educated and economically ambitious people has major positive implications for steel demand. The mega projects of the channel tunnel, a European network of high speed railways, and the London docklands are the forerunners of greater things. Still to come is another $200 to $300 billion by the year 2001 in identifiable major projects for highways, railways, airports, water and sewage systems. Add to that the demands of an increasingly affluent population for automobiles, appliances and housing. On top of all that place large increasing demands for electric power and you have a potential beyond anything seen during the 1970s and 1980s. In 1988 the EEC steel industry operated at 90% and in 1989 at 92% of effective capacity. A surge in spot prices indicated that 92% was close to the ceiling. This pace moderated in early 1990 but any slack will probably be taken up rather quickly."

Jan 1, 1990

By R. W. Raymond

In my former paper (Bans., xii., 410) I quoted the ruling of Judge Hallett, of Colorado, in the "Iron-Smuggler" case, tried before him in June, 1882. Under his charge, the jury in that case found for the defendants, practically declaring that the deposit on the outcrop of which the Iron Silver Mining Company's claim was located was not a " lode," or else that the portion of it within that claim was not the apex. The case was appealed, and the decision of the Supreme Court, given in February, 1886, is reported in 116 U. S. Reports, p. 529. It simply declares that there is nothing in the charge of Judge Hallett to warrant the setting aside the verdict. The definition of a legal lode given in that case, and quoted in my paper at the page above-named, is perhaps the best of several which Judge Hallet has pronounced. That is to say, his earlier definition, that " a lode or vein is a body of mineral, or mineral-bearing rock, within defined boundaries in the general mass of the mountain," is here accompanied with further explanations, which relieve it from the requirement on one hand, that the body shall be continuously ore-bearing if it he only well-defined, and, on the other hand, that the boundaries shall be well-defined if the ore-bearing body be proved to exist. So far as this particular case is concerned, the approval of this ruling by the Supreme Court merely prevents any re-hearing as to the face. Undoubtedly, the evidence was conflicting; and the jury chose to believe, for the purpose of that occasion, the " experts " who

Jan 1, 1887

By W. E. C. Coxe

Many of you who are interested in the manufacture of iron and steel, have no doubt heard of the "Wheeler process for combining iron and steel." Mr. Wheeler has formed a company, styled the "Combination Trust Company," whose business is to grant licenses for the use of this patent process in producing what he calls "iron-clad steel." It has been proposed to apply it in the manufacture of car or wagon axles, also to shafting, having steel cores or centres covered with iron; to tubes of steel with an inner and outer skin of iron ; to structural purposes, such as girders and beams; bridge and tie-bolts, where the strength of the iron and the rigidity of the steel would be desirable. In answer to a request from Mr. Wheeler, permission mas accorded him to make some experiments at the rolling mill of the Philadelphia and Reading Coal and Iron Company, at Reading, Pennsylvania, with a view to manufacturing some steel-headed rails. In making this kind of a rail two difficulties are encountered. If the iron is brought to the requisite heat to weld properly, the steel is likely to be burned; if the steel is cared for, to prevent burning, the several layers of iron are not brought up to the proper welding heat. Mr. Wheeler claimed that the steel slab covered with iron which he furnished for the head of the rail could net be injured by any heat to which it might be subjected in the ordinary course of heating the rail-pile. He claimed, also, that by this method the porosity, which he thought was characteristic of all solid rails of Bessemer steel, would be overcome. Four steel slabs were furnished for this experiment, being Bessemer steel of .61 carbon, made at the Edgar Thomson Steel Works, and covered with iron in one of the Pittsburgh mills. The slabs were in section seven inches wide by three inches thick, and the iron covering was one-eighth to three-sixteenths inch thick. Each slab was placed on a pile of iron made up in the ordinary way for a rail fifty-six pounds per yard and thirty feet long. The heating was under the personal direction of Mr. Wheeler, and

Jan 1, 1879

By C. S. Barrett

WhEN a collimated beam of protons or other energetic particles is scattered by a single crystal, the emerging particles produce patterns that contain much crystallographic information. Calculations of the trajectories of individual particles can predict with reasonable accuracy the complete pattern (which is related reciprocally to channeling, now studied in detail6) but the task is a lengthy one which has been completed for very few cases. A many-beam dynamic diffraction calculation of the patterns would be even more difficult and in some cases may be invalid. Because of these complexities, simple methods that will predict to a rough approximation the relative intensities of the lines in films of the back-scattering patterns of a given crystal are wanted. I have found a method which, although it is not a valid computation of intensities or of film darkening by either dynamic or kinematic diffraction principles or by trajectory calculations, nevertheless is found to be useful in practice. It has been tested on several crystal types,7 and is here tested on additional ones. The method consists in first calculating the structure factor F(hk1) for the (hkl) plane, of spacing d, by the familiar equation: where the summation extends over the atoms in the unit cell and fj is the atom scattering factor of the jth atom (using tables computed for electron diffraction, preferably those computed without exchange). Then the F values are squared and summed over all the orders, n, for which F2 has an appreciable value, giving a quantity: Finally, I, is expressed as a percentage of Ic for the

Jan 1, 1970

By A. K. Smith

Overexposure to noise remains a widespread, serious health hazard in the U.S. mining industry. Most other categories of illnesses and injuries associated with mining have improved, with the exception of hearing loss. U.S. Mine Safety and Health Administration (MSHA) coal noise data from 2000-2004 show that the continuous mining machine (CMM) is first among all equipment, accounting for 35% of noise overexposures. Joy Mining Machinery, in collaboration with the National Institute for Occupational Safety and Health (NIOSH), is conducting research to reduce noise generated by continuous mining machines. This paper describes a "JOY Designed for Noise Reduction" (JOY DNR; patent pending) tail section as a noise control for reducing the noise overexposures of CMM operators. Underground testing shows a 45% to 65% noise exposure reduction for the operator when comparing the JOY DNR tail section results to those for a standard machine. Utilizing this newly developed noise control, along with previously proven controls, will provide CMM operators an opportunity to be within the MSHA permissible exposure limit (MSHA-PEL). Mining Engineering, 2011, Vol. 63, No. 7, pp. 83-85. Official publication of the Society for Mining, Metallurgy and Exploration, Inc.

Jan 1, 2011

By A. B. Needham

Graphite is a raw .material of considerable importance in both waxy and peace. Two types of graphite, classified according to particle size as flake and fines, are used, but the former is in much greater demand. The principal wartime use of graphite is in the manufacture of crucibles for melting brass and special alloys of copper and steel. Other uses in both peace and war are as lubricants, for foundry facings, and in paints, electrodes, batteries, motor and generator brushes, and a variety of other commodities. . This paper describes the operations of the Southwestern Graphite Co. of Los Angeles, Calif., which produces both flake and fine graphite from a property in Burnet County, Tex.

Jan 1, 1946

By W. C. Meyer, R. R. Klimpel

A physical model of flotation, derived from viewing froth as a kinetic species since it constitutes the carrier of ore particles, not only agrees with and is simulated by engineering mathematical models, but is statistically verified by actual laboratory flotation data. The model couples the mechanical removal of froth using paddles with the more rapid interactions taking place in the bath. It clearly shows that the kinetics of mass removal is dictated by flotation cell dimensions, paddle speed, and, more importantly, froth characteristics. Some conclusions and model predictions are presented.

Jan 1, 1984

By T. G. Joseph, A. Chamanara

ABSTRACT: The chicken and egg scenario — where adverse truck motions cause ground deterioration and poor ground profiles cause adverse truck motions — is a downward deterioration spiral dominating our industry. If we remove one action, the reaction stops. A simple truck to excavator load data analysis and wireless communication system is outlined, which will provide visual assistance to the excavator operator in achieving improved load placement and balance in a truck body. This will reduce subsequent hauler duty cycle adverse motions and g levels that contribute to structural fatigue, higher tkph, reduced tire life, and ongoing maintenance of haul roads.

Jan 1, 2012

By S. W. Ip

Over the years, the importance of surface and interfacial phenomena has been neglected by the copper-nickel industry. As a result, little data on the surface and interfacial tension of the Ni matte and slag system are available in the literature. In view of the scarcity of information in this area, the surface tensions of the Ni-Fe-S system together with the Ni-Fe-S and fayalite type slag system were measured using the sessile drop technique. Drop images were obtained by X-ray radiography. For the Ni-Fe-S system, the results showed that the surface tension of the matte increases with matte grade. The surface tension behavior with changing matte grade showed a slight negative deviation from ideality. This indicated that FeS is slightly surface active in the nickel matte system. Results also indicated that small increase in sulphur content in the matte can decrease the surface tension quite significantly. The measured surface tension of the Ni-Cu-S system showed a linear relationship with the Cu2S content in the matte. The surface tension decreased with Cu2S content. Interfacial tension measurements showed a similar trend. That is, interfacial tension increased with increasing matte grade. The presence of MgO (-1.5%) and A12O3 (-6%) in the slag does not affect the interfacial tension value. Effects of matte surface tension on phenomena such as entrainment of matte in slag and infiltration of matte into refractory pores are discussed. The calculated flotation coefficients indicated that flotation of nickel mattes cannot be avoided by changing the matte grade. Filming of matte on bubbles can occur below a matte grade of about 19% Ni3S2. As for infiltration, refractory bricks containing high Cr2O3 will be easily wetted by matte regardless of matte grade. Therefore, bricks containing high Cr2O3 can easily be infiltrated by liquid matte.

Jan 1, 1993

By G. A. Apell, E. G. Howe, S. W. Hazen

"INTRODUCTION As a small amount of manganese was produced from the Lake Valley mining district of Sierra County, N. Mex., during the First World War, the district was reexamined in March 1941 by John H. East, Jr., an engineer of the Bureau of Mines, as a possible source of manganese for use during the Second World War. Preliminary examination indicated a substantial reserve of 25 percent ore, so it was recommended that an exploratory program of mapping and sampling be undertaken by the Bureau.The program was started in the fall of 1941 and was completed the middle of 1942. The project 3/ was divided into two parts: The first, an underground sampling program, formed the basis for the second, or churn-drilling program. Mapping and sampling of old underground workings were begun in October and finished in November 1941, whereas churn drilling was begun in February and completed in June 1942."

Jun 1, 1947