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By Norman B. Pilling, George P. Halliwell

The effects of lead and tin up to maximum contents of about 0.1 per cent. each, in the presence of oxygen between 0.04 and 0.30 per cent., have been studied. Tin is retained efficiently in the oxidized condition, whereas lead is not. An approximate relation between the lead-oxygen and tin-oxygen contents is deduced which, if observed, permits the presence of these elements without detrimental effect. Excess of lead beyond this limit affects ductility and rolling properties adversely and an excess of tin correspondingly diminishes the conductivity. It is shown that copper carrying a combined lead and tin content of several hundredths per cent., yet fully equal in quality to electrolytic wirebar, may be produced under commercial conditions. Tin is not normally found in more than bare traces in current grades of American electrolytic copper, and lead is rarely found to more than a few thousandths per cent. In the electrolytic refining of copper these metals do not present great difficulty in separation and their presence in any considerable amount in copper that has been refined by this method need not be tolerated. On the other hand, the effect of these elements is not entirely academic, as a considerable tonnage of scrap copper liberally contaminated with them has been reclaimed by the fire-refining process into metal with a residual lead and tin content of several hundredths per cent., yet having excellent working properties and fully equal in quality to current grades of electrolytic wirebar. Such copper has been found entirely suitable for use in the manufacture of electrical apparatus. In the absence of oxygen, tin is known to depress the conductivity rapidly, and lead to impair ductility and the rolling properties, yet the effects of these metals on commercial grades of copper—i. e., copper containing from 0.03 to 0.10 per cent. of oxygen—apparently has not received systematic attention. Occasional reference is made to the fact that in the presence of oxygen lead may be tolerated, yet Addicks says,1 in regard to overpoling: "The unstable condition can be controlled by adding certain substances, notably lead, in small quantities, but as mere

Jan 1, 1926

By I. Cornet

With the greatly expanding use of magnesium during the war, it appeared necessary to the War Metallurgy Committee that the notch sensitivity of magnesium alloy extrusions be further investigated and the influence of various factors upon notch sensitivity be noted. Accordingly, the National Defense Research Committee of the Office of Scientific Research and Development placed a research contract with the University of California, supervised by the War Metallurgy Committee. The work discussed herein was done under "Restricted" Project NRC-21, reported in Dec. 1943~; it has been released for publica-tion by the O.S.R.D. Scope of the Investigation The notch sensitivity of various magnesium alloy extrusions was determined under axial tension, and also under several conditions of nonaxial tension. Hardness, grain size and other metallographic features were observed; stress-strain data were obtained, and the chemical compositions of the alloys were determined, in order to correlate these quantities with thc notch sensitivity. Notch sensitivity under axial tensile load was determined for a few specimens which had been cold worked to various degrees by tensile prestraining. Magnesium alloy extrusions studied included Dowmetal 0, X, J, and A(. For comparison, extrusions of aluminum alloy 24s-T, cast bars of aluminum alloy 122-T2, and cast bars of magnesium alloy C were also tested. The specified chemical composition of these alloys is given in Table I. All bars tested were within specification limits of composition. Investigation of thc tensile notch sensitivity of various magnesium alloy extrusions, under conditions of axial and eccentric load, showed little or no correlation with stress-strain or other conventional data. Since the many uncontrolled variables present might mask significant relationships, one alloy was selected for intensive study. Magnesium 0 alloy extrusions were subjected to experimental heat treatments, and the ,Changing hardness, tensile strength, microstructure, and notch sensitivity observed. Experimental Techniques and Procedures Tensile Testing Bars used for axial loading were machined with % in.- and with 34-in. minimum diam1 and included specimens with 60" V notches (Fig I and 2). Each V-notched specimen was roughed out carefully and then finished with a honed tool. These Y-notched bars were sampled frequently, sectioned, polished, and examined at 500 X magnification to control

Jan 1, 1949

By Laing W. P, Neill D. M, O&apos

The Reward polymetallic massive sulphide deposit occurs 35 km south of Charters Towers, adjacent to the Highway gold deposit (Fig. 1). It is hosted within rhyolitic lavas and interlayered volcaniclastics of the Cambro-Ordovician Mt Windsor Volcanics. Reward is a "blind" deposit discovered in 1987 after a long history of exploration by various companies in the area. The main pyrite dominant massive sulphide body occurs under 100m combined thickness of Tertiary fluviatile sediments overlying deeply weathered gossanous volcanics. The exploration case-history provides a striking example of how geological and structural models can be built up almost exclusively from drill information. Four different styles and ages of mineralisation are present: 1) volcanogenic Cu+Pb+Zn+Ag+Au massive sulphides of probable syngenetic origin; 2) remobilised Cu+Au in massive pyrite of metamorphic/deformational origin; 3) supergene and 4) oxide Cu+Au mineralisation of weathering origin. The massive pyrite body, containing chalcopyrite lenses, transects the stratigraphy and is inferred to contain in excess of 5 million tonnes. Overlying the primary mineralisation a supergene chalcocite rich zone contains a measured/indicated resource of 634,231 tonnes of 6.77% Cu which includes 287,000 tonnes of 1.32 g/t Au and 18 g/t Ag. In addition a measured/inferred oxide resource of 309,000 tonnes of 5 g/t Au and 27 g/t Ag overlies the supergene zone.

Jan 1, 1989

By E. F. Poncelet

Forty years ago A. A. Griffith developed a theory explaining why brittle materials displayed such low tensile strengths.' He based his views on two points. First, he found himself compelled to assume that all brittle materials are replete with flaws, cracks, and other defects that act, although quite invisible, as large stress raisers. Second, he applied the "theorem of minimum potential energy," which says that the total potential energy of a system must pass from the unbroken to the broken condition by a process involving a continuous decrease in potential energy. By this means he satisfactorily accounted for the noted low strength of such solids and also for the wide spread obtained in experimental measurement of these strengths. So successful has the theory been that it is favored by some to this day. Unfortunately this theory is of limited use beyond the explanation of these two noted phenomena and it is keenly felt that a better theoretical insight into the physics of the fracturing process is needed as the volume of experimental evidence accumulates. The author proposes in the following to build on the fundamentally sound concepts of Griffith and, with the help of increased theoretical knowledge over that available to Griffith, develop a mechanism for frac-ture which will provide far greater understanding of the experimental evidence accumulated to date than is possible from the original Griffith idea. THE GRlFFlTH THEORY Very little progress indeed can be made without accepting the first postulate of Griffith which supposes all brittle solids to be full of microcracks. It would be difficult indeed to find a better mechanism for the small strength of such brittle materials, in conjunction with the fact that the energy that must be expended for comminution is by no means small. The postulate of the existence of the microcracks permits the breakup of the various bonds a few at a time by concentrating the stress at the tip of the progressing crack, while the total energy expended is the same as if they all had been ruptured simultaneously. The only flaw in the argument is that no reasonable explanation has been proposed to account for the genesis of such cracks. Indeed their very presence is in violation of the Griffith second postulate, the potential energy theorem. This theorem is straightforward for isothermal processes, and, in spite of Griffith, there is some doubt that treating the problem isothermally is legitimate. The surface energy of bodies is a free energy, not a potential energy as stated by Griffith, and the production of new surface free energies is not necessarily an isothermal process. There is ample evidence to the contrary. Generally speaking, if heating a body increases its surface area, then, by virtue of Le Chatelier's principle, any increase of that area by other means will tend to lower its surface temperature. Lord Kelvin calculated the actual cooling that resulted in drawing out a film of liquid.2 R. A. Houston calculated the surface cooling that resulted in stretching a metal wire.3 These calculations were made by applying the Carnot cycle to the process and evaluating the thermodynamics thereof. IRREVERSIBILITY OF THE FRACTURING PROCESS While Griffith was very careful not to say so, the impression gained from studying his papers is that he considered the fracturing process as reversible, that is, a succession of quasi-equilibrium states. There is ample evidence that it is not. The indication that the new surfaces produced by the propagation of a crack are cooler than the original body points to an irreversible heat flow from the interior to the new surfaces to equalize the temperatures. If the process be reversible, any crack accidentally formed should immediately close up as, in the absence of any strain energy, the potential energy would thereby be lowered. The fact that they do not, constitutes a paradox. Such paradoxes are nothing new where certain phenomena that propagate from minuscule nuclei are assumed to be reversible. Such is, for instance, the condensation of a pure saturated vapor that is suddenly chilled by adiabatic expansion. At the beginning the tiny droplets that are formed should be only a few angstroms in size, but the vapor pressure at such droplets is so high that they should evaporate at once. A similar situation arises if a saturated pure solution becomes super-saturated upon cooling; the first tiny crystal nuclei should dissolve as fast as

Jan 1, 1964

By E. P. Klier

THE work of Klier and Lyman1 on the bainite reaction has led to the full description of this reaction for medium-carbon low-alloy steels. Certain experimental data reported by Klier and Lyman appear, however, to be improbable of obtaining in very high-carbon steels. The study herein reported consists of an analysis of the transformation characteristics of a 3 per cent chromium, 1 per cent carbon steel by means of X-ray and metallographic methods. From the results obtained it is concluded that the bainite reaction in this steel is more complicated than that reported by Klier and Lyman for the low-carbon low-alloy steels. However, the mechanism of bainite formation in this steel appears to be essentially the same as proposed for the low-carbon low-alloy steels with the modification that the first volumes to transform are carbon-rich rather than carbon-poor. EXPERIMENTAL PROCEDURE The analysis of the steel studied was: Cr, 2.89; C, 1.02; Mn, 0.33; Si, 0.35; S, 0.012; P, 0.020. The stock was received from the Carpenter Steel Co. in rolled bars. Specimen Preparation Specimens were austenitized at 1200°C. (2192°F.) for 25 min. in purified nitrogen. The resultant A.S.T.M. austenite grain size was 0-1. Isothermal transformation was allowed by quenching the specimens into liquid metal baths controlled to ±5°C. at 540°C. (1004°°F.) and above, and to ±2°C. at 490°C. (914°°F.) and below. Following the desired degree of transformation all specimens were water quenched. Metallographic Examination Specimens 1/4 in. round by 1/4 in. were used for metallographic examination. Etchants used were Vilella's reagent (1 gram picric acid, 10 ml. hydrochloric acid to make l00 ml. ethyl alcohol solution) and alkaline sodium picrate (electrolytic). Vilella's reagent was effective in revealing all microconstituents, while the alkaline sodium picrate developed the carbon-rich structures or carbides only. X-ray Examination Two X-ray techniques were used-the Debye-Scherrer method and a back-reflection method. The small specimens necessary for the Debye-Scherrer method were austenitized and then allowed to transform, or were cut from the larger metallographic specimens. The metallographic specimens were used for the back-reflection X-ray analysis. When it was desirable to determine the structure of the carbide present, sliver specimens were electrolytically etched to develop a carbide coating, then were exposed in the cameras. This technique was frequently necessary to allow positive identification of the carbide.

Jan 1, 1945

By Reginald E. Hore

Since the discovery of silver at Cobalt, Ontario, in August, 1903, more than 100,000,000 oz. of silver have been produced by the mines in the Nipissing district, and there is reason to believe that at least as much more will be produced in the nex five years. The estimated value of the aggregate output o ore to the end of 1910 is $48,327,280. The ore yielded 93,977,833, oz. of silver and was mined at a net profit of abou $16,000,000. For 1910 the production was 30,558,825 oz., valued at $15,436,894, and yielding a profit of about $9,000.000. The details of the production of the Cobalt district for the years 1904 to 1909, inclusive, as reported by the Ontario Bureau of Mines, are given in Table I. The shipments from Cobalt are in the form of smelting-ore, concentrates from milling-ore, and bullion. The smelting-ore is largely high grade, averaging about 3,000 oz. per ton A smaller return is from what is called low-grade ore and which

Jan 1, 1912

THIS chapter and the one following deal with the heat quantities involved in open-hearth steelmaking, including the thermal efficiency of the furnace as a generator of high-temperature heat, the heat storage in the steel and slag produced and in the furnace walls, and the heats of the various chemical reactions involved in combustion, in the formation of slag, and the refining of steel. The fundamental laws to be considered are the simplification of the first two ' laws of thermodynamics as applied to problems involving sensible and potential (or latent) heat only 1. Heat input equals heat outflow plus storage. 2. Heat may be transferred only from a hotter body to a colder one. The first of these laws relates to the various heat quantities or the "heat balance" of the process. No one has as yet made an open-hearth heat balance that came out almost exactly balanced, and we assume that the cause lies in the difficulties of accurate temperature and flow-rate measurements at the high temperatures involved and the inherent complexities of flow distribution, air leakage, etc., present in any real, open-hearth furnace system. Some idea of the magnitude of the heat quantities involved can be obtained- by a brief, crude outline of the heat balance of a 90-ton heat of steel. We will assume a 60 to 70 per cent hot-metal charge in a fairly fast working and only moderately efficient furnace, burning fuel oil, with a fuel consumption of around 4 million B.t.u. per net ton. of ingots produced. The time from start of charge to tap is 9 hr. During this period, the oil burned represents 360 million B.t.u., and the sensible heat in the preheated air at the port ends is 117 million B.t.u. so that the total heat input at the ports is 477 million B.t.u. Heat stored in the steel and slag at the end of the heat, plus the various amounts absorbed by certain bath reactions, amounts to a total of 195 million B.t.u., but 120 million of this is supplied by the heat in the hot metal and by various heat--evolving reactions in the bath, so that only 75 million B.t.u. need be supplied to the bath by the flame.

Jan 1, 1944

By Shianny Cruz Vasquez

Peru is a country with a complex physiography due to the Andes uplift that expose the different ore deposits. Actually Peruvian mining produces a variety of metal commodities and has one of the world’s largest mining. It is the third-largest global producer of copper, silver, zinc and tin. Within Latin America is the largest producer of gold, zinc, tin and lead. The importance of this research was to determine the toxic elements source and the current state of surface water and groundwater all the way from the top until it empties into the Tambo River and assess their, that impact have the toxic contaminants on the environment and the human health of the surrounding Communities and provide a management and decision-making tool to prevent socioenvironmental conflicts.

Sep 1, 2017

By G. W. Healy, W. D. Forgeng, N. R. Griffing

The liquidus surface of the C-Cr-Fe system to 1900°C has been mapped from carbon solubility and freezing point measurements, metallographic observations, and published data. In the graphite field, the surface drops precipitously to meet a slope descending from the Cr3C2-C join through the mixed carbide fields to a meandering eutectic valley; this flows from the Cr-C to the Fe-C edge. On the low-cavbon side of the valley, the surface rises to the chromium corner. 1 HE purpose of this inquiry was to gain a more complete knowledge of the C-Cr-Fe liquidus surface. This required an extensive study of carbon and chromium-rich alloys which, in the past, have received the least attention. Sanbongi el al.1 measured the solubility of carbon in liquid alloys containing up to 25 wt pct Cr at temperatures of 1460" and 1545°C and found that it increased with chromium content and temperature. Lucas and wentrup2 also made solubility experiments in graphite crucibles, but at higher chromium contents in the range of 38 to 80 pct and at temperatures of 1550" to 1700°C; however, their experiments were relatively few, and the effect of temperature was not consistent. The present investigation included compsitions ranging from 0 to 94 pct Cr and 1.4 to 11.7 pct C at temperatures up to 1800°C. Saturation experiments in graphite crucibles, thermal analyses during freezing, and metallographic and X-ray diffraction studies were employed to obtain desired information which, together with published data from other investigations about the binary edges and the ternary system at lower carbon levels, made possible the construction of a comprehensive C-Cr-Fe liquidus surface. C-CR-FE LIQUIDUS SURFACE The derived ternary liquidus surface is shown in Fig. 1 where the solid curves are liquidus isotherms. The dashed curves and the binary edges are the liquidus field boundaries of the primary crystals, the arrows along these boundaries indicating their direction with decreasing temperature. Each intersection of three internal boundaries is the composition of liquid involved in four-phase isothermal equilibrium with the three primary crystals whose liquidus fields touch there. It may be observed that a total of six four-phase equilibria occur at melt temperatures. The general topography of the liquidus surface consists of a eutectic valley sloping down from the Cr-C edge at 3.2 pct C to the Fe-C edge at 4.25 pct C. The liquidus surface rises in two directions from the valley, one hillside terminating at the Cr-Fe edge while the opposing hillside rises toward the carbon corner out beyond the top edge of Fig. 1. Both hillsides are interrupted by intersections of surfaces or joints representing the liquid colmpositions of various three-phase equilibria. Seven primary crystals occur, namely a(bcc), ?(fcc), graphite, (Fe, Cr)3C capable of dissolving as much as 15 pct Cr, and three different chromium carbides in which iron is partially soluble by substitution for chromium. The composition ranges of the primary l~hases at melt temperatures are shown

Jan 1, 1962

By H. Schrader, E. Houdremont, H. Bennek

The different influences exerted by the various alloying elements in iron and iron-carbon alloys give rise to a great number of complexities, which are difficult to grasp. It is important therefore to study any systematic relations that may exist between the effects exerted by the various alloying elements, in order to obtain a general classification and thus a clearer conception of the nature of alloy steels. A systematic survey of the alloys of iron, based on an investigation of the binary equilibrium diagrams, was recently published by Wever. Although his work deals little with properties of importance in works practice, its purpose being rather to point out the theoretical agreement among the types of binary equilibrium diagrams and the position of the alloying elements in the periodic system (atomic radii, etc.), the classification proposed nevertheless also suggests relationships among the properties of the alloys in question, even though the alloys may contain carbon in addition to iron and the alloying element. Wever divided the alloys of iron into one group exhibiting an open or enlarged gamma field and another exhibiting a closed or restricted gamma field, with both groups capable of further subdivision depending upon whether a continuous series of solid solutions is formed, or, owing to the separation of compounds, etc., only a limited series. Thus all alloying elements which with iron form a closed gamma field, a "gamma loop," produce alloys that beyond the composition corresponding to the greatest extent of the gamma loop are composed of ferrite alone at all temperatures. Alloys of this composition accordingly are not susceptible to ordinary heat treatment because of the lack of transformations. Steels of this class may thus be divided into steels that contain less than the critical amount of alloying element, and are subject to heat treatment, and those that contain more than the critical amount of alloying element and are not subject to heat treatment. Thus chro-

Jan 1, 1935

By Daniel Martin

THE dendritic pattern of steels shown by deep etching is used exten-sively as a guide in the inspection and control of the great majority of steels used in ordnance construction and for many applications in indus-try. The value of macroexamination lies in the fact that it enables a qualified observer to make deductions concerning the general quality of relatively large pieces of metal. Not the least of these general character-istics is the nature and extent of the dendritic segregation in the steel, either in the cast condition or after mechanical or thermal treatments. PREVIOUS WORK Detailed methods for macroetching were outlined by Yatsevitch1 and have been standardized by the American Society for Testing Materials. A comprehensive study of the occurrence, origin, and the chemical and crystalline nature of the dendritic structure was given by Keshian.2 The marked persistence of dendritic segregation in nickel steels is fully recognized and has been discussed by Sauveur and Reed' and by others. Very little, however, has been written on the effect of the various elements on the macrostructure of steels, and the purpose of this report is to submit evidence concerning the influence of chromium, nickel and molybdenum on the macrostructure of some 4 by 4-in. ingots cast and treated under closely controlled conditions.

Jan 1, 1939

By R. E. Miner, J. K. Jackson, D. F. Gibbons

Internal-friction measurements were made during isothermal aging treatments of 18 pct Ni maraging-steel wires between 420° and 612°C. A sharp initial drop in the internal-friction level was interpreted in terms of a rapid dislocation recovery reaction. The rate of the recovery was found to be independent of temperature. Truncation of the recovery reaction was apparent in those systems that exhibited the rapid age-hardening characteristics of the maraging steels. It is proposed that this initial hardening response is the result of a low activation energy preprecipitation reaction involving molybdenum. A gradual rise in the internal-friction level at longer aging times was associated with the precipitation of a molybdenum-containing precipitate. CONSIDERABLE research effort has recently been devoted to the mechanisms responsible for the high strength and toughness of 18 pct Ni maraging steels. These bcc martensitic alloys are found to harden during aging at temperatures between 400° and 600°C. The aging response is very rapid with more than half the total hardness increase occurring within the first few minutes of aging, Fig. 1. Precipitate particles have been observed in the later stages of aging by a number of investigators.'-' While the identity of the precipitates remains the subject of some controversy, one or more of the intermetallic compounds, Ni3Mo, Ni3Ti, and Fe2Mo, are almost certainly involved. Heterogeneous nucleation of precipitates at dislocations has been noted8 and cobalt is believed to enhance the formation of fine, homogeneously distributed particles by lowering the solubility of the alloying elements in the martensitic matrix.3,7 Transmission electron microscopy studies of the initial hardening behavior have not been fruitful. Strengthening mechanisms based on atomic ordering have not been generally supported by X-ray and neutron-diffraction experiments.9 In the present investigation, the aging reaction was studied using isothermal-aging internal-friction measurements. The marked sensitivity of internal friction to short-range diffusion and precipitation processes has provided a convenient tool for the elucidation of the strengthening mechanisms operative in the maraging steels. EXPERIMENTAL PROCEDURE An upright torsion pendulum was used to measure the internal friction of several maraging steels during isothermal aging. The pendulum was placed in an atmosphere of helium at a pressure slightly less than atmospheric. To permit measurement of internal friction during the first minutes of aging, the specimens were rapidly heated by passing a current through them in a manner similar to that described by Ang and Wert.10 Thermal gradients in the specimen were largely eliminated by using specially designed specimen grips11 which produced temperature variations of less than 1 pct over 90 pct of the specimen length and less than 3 pct over the entire length at aging temperatures up to 620°C. A proportioning strip-chart program controller was employed to maintain constant specimen temperature during treatments of up to 36 hr duration. A number of vacuum-melted laboratory heats having compositions near that of a typical commercial 18Ni-7Co-5Mo-0.4Ti alloy were investigated. The amount of cobalt was varied from 0 to 7 wt pct in five of the heats. Either molybdenum or titanium was omitted in the remaining two heats. The alloy desig-

Jan 1, 1967

By K. MacMaster

"This paper deals with the history, development, present and future of the Employee Assistance Programs in place at the Inco Ltd. operations in Thompson, Manitoba. It should be noted that, although many similar programs exist in various industries and jurisdictions, these programs had to be fine-tuned to meet the needs of Inco employees, having in mind the helping professional resources available in Thompson and its geographic location. IntroductionIn the late 70s, many Canadian industries and the Canadian Labour Congress and their affiliates commenced discussions on the value of the Employee Assistance Program (E .A.P.) philosophy to both management and labour.In the contract signed between Inco Ltd., Manitoba Division and Local 6166, U.S.W .A. in 1981, a commitment was made to establish a joint E.A.P. for the hourly workforce in Thompson, Manitoba. With this background and sequence of events in mind, it is appropriate to explain the methodology and the steps that were taken for the implementation of the hourly program. Development of Hourly ProgramIt was agreed by the company and the union that the committee to develop the program should consist of equal numbers from both sides: three active union members plus an advisor representing the Union and three supervisory personnel plus an advisor representing the Company; in addition, a person familiar with E.A.P.s from the Alcoholism Foundation of Manitoba was to act as a facilitator. The Union appointed a social worker who was working as a counsellor for union members as their advisor , and the company appointed a staff employee who had worked voluntarily in the field of alcohol and drug abuse for many years. The makeup of the committee was extremely important in order to give credibility to the entire process. The makeup of the committee is shown in Table 1.The facilitator selected from the Alcoholism Foundation of Manitoba was well known in the community and highly respected in his profession."

Jan 1, 1989

The Favona Underground Project is located approximately two kilometres east of Martha Mine Open Pit in Waihi, 150 km south east of Auckland, New Zealand.   The underground reserve of 354 koz Au contained in resources of almost 600 koz lies within 600 m of the existing process plant presenting an attractive development target in a challenging environment.   The Martha Mine Open Pit is surrounded by urban housing on the north western edge of Waihi township and the Favona Underground abuts residences on the eastern edge of town. Environmental, community and social licence aspects influence project strategies as the new underground mine extends mining in a town that is planning for closure of current open pit operations in late 2006.   The Favona Underground Project has successfully passed through a detailed feasibility study, the third stage of the five stage Newmont project appraisal system. Methodologies used in the feasibility study and parallel permitting draw on a high level of stakeholder involvement to streamline the development and permitting phases.   This paper discusses the project appraisal process and design innovation required for developing an underground mine adjacent to town.

Jan 1, 2004

Mt. Whaleback is in the Pilbara region of Western Australia approximately 1200 kilometers north of Perth, the State capital. In this deposit the Mt. Newman Joint Venturers are mining ore reserves totalling 1500 million tonnes of high grade hematite averaging 64.0% Fe. In addition to Mt. Whaleback, 38 ore bodies have so far been identified outside Mt. Whaleback on the Company's remaining 75,000 hectares of lease area. These ore bodies contain major tonnages of iron ore. Extraction at present is planned at a rate of 37 million tonnes per annum at an ore-to-waste ratio of approximately 1 to 1.4. The ore is railed north to Port Hedland on the Indian Ocean where the different products are screened, crushed and blended prior to shipping. The purpose of this paper is to acquaint the reader with the facilities installed in the Mt. Newman operation to form a background to the sampling techniques employed, describe the precisions which were achieved in experiments conducted February through June, 1976 and also to assess the degree of blending which takes place during the various processes and to put a quantitative measure to the degree of blending. There have been many excellent papers written on the more theoretical aspects

Jan 1, 1976

By T. M. Broderick

InveStIgations into the possibilities of economically mining and concentrating low-grade iron ores of the Lake Superior region are attracting increasing attention. Among the organizations that are carrying on the work are the United States Bureau of Mines, the State of Minnesota (which spends about $80,000 annually on problems of the iron and ferroalloy ores of Minnesota), and the State of Michigan (which spends about $10,000 annually of its iron-ore research). Several of the mining companies are also financing research. Of the states in the Lake Superior district, Minnesota has done most in iron-ore concentration. In 1930, thirty-seven concentrating plants were in operation on the Mesabi Range, beneficiating about one-third of the total ore shipped. About one-half of these plants reduced silica; the others reduced moisture or improved the structure of the ore.' Research into the possibilities of magnetic concentration of the Eastern Mesabi magnetite ores indicates that vast tonnages of that ore may be utilized at a profit in the not distant future. Magnetic concentration has also been tried at Sellwood, Ontario, on the Moose Mountain deposit, and at the Berkshire mine in Wisconsin on the magnetic ores of the Western Gogebic Range. There have been few attempts to concentrate Michigan iron ores. In order to determine the possibilities of such concentration, iron-ore research has been carried on at the Michigan College of Mining and Technology for the past few years. After a general survey of the iron ores of the state, a program of more detailed experimentation was outlined, starting with work on the Ironwood formation of the Gogebic Range. The results of this research led to the belief that gravity methods will produce fairly satisfactory concentrates from the parts of the iron formation that are made up of comparatively thick alternating beds of rather high-grade ore and lean chert. About 85 per cent of the iron and steel produced in the United States comes from ores of the Lake Superior district. The reserves of direct

Jan 1, 1935

By C. B. Sclar and

A graphical solution is presented for the equation v =v &-cU where vb is the volume of liquid b of density 6 that must be added to liquid a of volume va and density d, in order to obtain a heavy-liquid solution of preferred density dm for mineral fractionation. The equation is valid only for pairs of liquids whose volumes are additive, but empirical density-composi-tion data show that this condition is met over wide compositional ranges by all of the heavy solutions that are commonly used for mineralogical analysis. The chart is a nomograph which consists of two horizontal volume scales ad a vertical density scale arranged so that one volume scale occurs on each side of the density scale. All the scales are linear. For two liquids of density d, and &, respectively, each volume scale has an independent level on the density scale, ad the graphical solution for vb on the nomograph is obtained by construction of one straight line. The chart can be prepared easily to cover any density range with any desired accuracy by proper selection of the scales. Heavy-liquid separation of particulate samples is an indispensable analytical procedure in the mineralogical and mineral-process ing laboratory. Heavy liquids may be used 1) to isolate specific minerals in the form of high purity products or to fractionate samples into several products with density limits for petrographic, chemical, spectrographic, and X-ray diffraction analysis,'-' 2) to determine the density of minerals,'-l4 3) to facilitate the recognition and identification of optically similar associated minerals,15 and 4) to determine quantitatively the degree of liberation of ore minerals in ores and mill products at various limiting sizes." The preparation and recovery of heavy liquids suitable for mineralogical analysis are discussed fully in the literature and operational procedures and special equipment for heavy-liquid separation are described in numerous references.'747837' 13,18,25-42 Useful tabulations of heavy liquids for mineralogical analysis are given by Tickell, Mil-ner,' Twenhofel and Tyler,' and Lange and a very complete up-to-date list of minerals arranged according to increasing density is given by Mursky and Thompson. USEFULNESS OF THE DENSITY CHART For any particulate sample, the limiting densities selected for its fractionation by means of heavy- liquid separation depend on the respective densities of the constituent minerals and the specific objectives of the separation. In many instances, the densities of readily available and practicable heavy liquids do not coincide with those that are required, and suitable liquids of the proper density are obtained by dilution with miscible liquids. In the general case, one may wish to mix either a pure liquid (A) or a solution of two miscible liquids (AP,,) of known density with either a pure liquid (B) or a different solution of the two miscible liquids (A,B,) of higher or lower density in order to obtain a final liquid of the preferred density. In conventional practice, the latter is reached empirically by trial-and-error addition of increments of one liquid to the other. The density of the final solution may be determined either by accurately weighing a known volume of the final liquid,'' 532;4;40, or by means of I)a Westphal balance, 2)a hydrometer, a refractometer in the case of binary liquid systems for which density-refractive index data are available,15 4) natural or synthetic .indicators of known density, a pycno-meter. Like all trial-and-error methods, these procedures are time consuming and many require special equipment which may not be available, The purpose of this paper is to show that the volume of a liquid of known density which is to be added to another liquid of known volume and density in order to obtain a solution with an intermediate preferred density may be determined rapidly and accurately by a graphical method provided that the two liquids form ideal or quasi-ideal solutions whose volumes are additive. Empirical data47'8~'8~4B'49 show that solutions prepared from pairs of miscible

Jan 1, 1961

Developed and built in 1982 for simultaneous bathy-metric and reflectivity mapping of the deep ocean by the Hawaii Institute of Geophysics, SeaMARC II was a breakthrough in sea-floor mapping technology. The design was developed cooperatively by industry and academia, and the system has served as a prototype for a new generation of mapping tools for operation in both shallow and deep water.Research programs using the SeaMARC II system have focussed on basic research into the geophysical evo-lution of the Pacific, ranging from intra-atoll mapping to surveys of the deep-sea trenches. During the past few years most work has been concentrated on detailed investigations of the morphology of mid-ocean spread-ing centers, seamounts, and the subduction zones which surround the Pacific. The detail provided by the high resolution, 10-km wide side-scan sonar images of fault and fold structures, combined with the swath of bathy-metric information obtained simultaneously, allow previ-ously unattainable analysis of seafloor morphology and are leading to development of detailed models for ocean crust genesis and deformation.

Jan 1, 1990

By Orrin P. Peterson

The decision of the Supreme Court -of the United States not to review the findings of the lower courts closes an interesting chapter in the mining litigation that has arisen as a result of the extralateral feature of the mining law. The time seems opportune to record some of the important geological features, and also some of the legal features, of the controversy, in the hope that these will be permanently accessible to members of the mining profession. After many rumors of litigation, the Utah Consolidated Mining Co. sued its neighbor for the ore that had been, it was alleged, wrongfully extracted from its so-called Yampa limestone lode. This ore lay beneath Utah-Apex surface and was claimed by virtue of the extralatera1 rights conferred on the Utah Consolidated Co. through the ownership of certain specific mining claims, one of the principal claims being the Yampa. Previous to bringing suit, the Utah Consolidated Co. had strengthened its position by purchasing the Old Yampa mine and by making an agreement with the Utah Metal & Tunnel Co., which gave it clearer title to the outcrop of the Highland Boy limestone. Access to the workings of the Utah-Apex Co. was secured and reciprocal privileges gave Utah-Apex representatives the right to enter the properties of the Utah Consolidated Co. This resulted in the Utah-Apex immediately bringing countersuit for ore alleged to have been wrongfully extracted from under its surface in the Leadville country, see Fig. 4. Six cases came up for consideration: five related to the original suit and the countersuit, and one related to the Dana extralateral claims of the Utah-Apex Co. Well-known attorneys, geologists, and mining engineers were engaged by both sides, and thousands of feet of development work were done to prove or disprove ideas that would sustain the contentions of the opposing sides. Models of wood, wire, and glass were constructed to present clearly to the court the actual physical relations. These models were also of great value to the attorneys and witnesses in clarifying hazy impres-

Jan 1, 1924

By J. J. Rutledge

On Sept. 4, 1914, Mine No. 1 of the Union Coal Co., Adamson, Oklahoma, suddenly caved, entombing thirteen miners whose bodies were never recovered. The seam of coal mined, the Lower Hartshorne, averaged 5 ft. in thickness and dipped at an angle varying from 22" to 30n. The strata overlying the coal seam were sandstones and shales. The mine was worked by the pillar-and-room method, the rooms being driven directly up the dip of the seam. All coal was blasted off the solid. Rooms were turned on short centers and room pillars were thin and irregular, as shown in Fig. 1. Fig. 2 is a cross-section of the form; showing the mine workings. Some cracks had been observed on the surface, it is said, at least a month before the squeeze occurred, but the collapse of the mine workings came very suddenly. As is usual when squeezes occur on such steep dips and the pillars fail, the crush progressed rapidly down the dip until it reached solid coal; there was a line of break, or draw, over in the solid coal. Several well-defined cracks appeared on the surface, after the mine had squeezed, but there was no appreciable subsidence of the surface, the weight seemed to be thrown entirely to the dip. About one year after the squeeze, and after the workings of the adjoining mine, NO. 4, had been retimbered and made safe, the writer inspected the tenth north (right) entry, or lift, off of No. 4 slope, which was below and fairly near the lowest caved portion of mine No. 1. The roof shale was composed of thin layers, which had been bent in somewhat the same manner as the leaves of a book having flexible covers are bent when the book is folded or rolled up in the hands. Though the mine workings are immediately beneath the streets and buildings of the mining town of Adamson, business was not disturbed by the squeeze, so far as any subsidence of the surface was concerned. No surface monuments were available and no elevations were taken, but the mine workings had been accurately surveyed and traversed, and the streets of the town overlying the mine workings had been carefully platted on the mine map, so that it was possible to locate accurately the cracks on the surface.

Jan 1, 1923