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By E. P. Mathewson

THE experiments described in this paper were made at the Washoe Reduction Works, Anaconda, Mont., for the purpose of determining the relative speed of elimination of the iron, sulphur and arsenic during the process of bessemerizing copper-mattes. The samples were taken from a horizontal "barrel" converter, 8 ft. in diameter and 12 ft. 6 in. long, having an average charge of 9 tons of matte, and blown with a 16-1b. air-pressure. All samples were taken with the blast on, turning the converter from its normal blowing-position to nearly verti¬cal, so that a conical mold, with a long handle attached to a horizontal rod, could be introduced from a platform above the converter into the mouth of the converter and a sample taken. The difficulties of taking a sample with the blast on are appar¬ent, and the irregularities of the lines in Figs. 1, 2 and 3 can be readily accounted for by the amount of slag in the samples. On the whole, the plotting of the results gives comparatively uniform lines, considering the conditions. The samples were taken by the regular sampling-force of the works at 10-min. intervals, as shown in Tables I., II and III, which also give the chemical analysis of the samples so taken. The test shown in Table I. was made with a new converter; that of Table II with a converter that had made three charges and had been cleaned out; that of Table III with a converter that bad blown one charge to white metal, and had then been " washed " out and used for the test. In plotting these results, it was necessary to take, as a basis, the percentage of copper in the samples. This basis does not exactly represent the true condition, since the volume is constantly decreasing and a certain quantity of copper passes into the slag, but it is as near as can be obtained in practice. Take, for instance, in Table I., the sample No. 5, which shows : Cu, 59.9;

Jan 1, 1907

By E. L. Litchfield

Spark ignition of combustible-gas mixtures is a relatively old subject of investigation and has been treated both experimentally and analytically by many people. Elements of static and current electricity are almost always present in mining and industrial operations, and the spark can be an extremely efficient source of ignition. Thus the practical interest of such problems as the "intrinsic safety" of electrical apparatus is obvious. Ignition and quenching phenomena are the primary laboratory representatives of combustion phenomena that are dynamically nonsteady, and such nonsteady phenomena playa considerable part both in industrial processes and in safety matters, although they are of less immediate practical interest. Considerable effort has been expended by the Federal Bureau of Mines in investigations of spark ignition.5 6 7 8/ Primarily, this work has established the significance of several of the parameters involved. Although the

Jan 1, 1959

By David Reger

THE value of carbon ratios in determining the boundaries of possible oil deposits appears to have passed the hypothetical stage. The theory that the ratio of fixed carbon in pure coals is an, invariable index of incipient metamorphism in both, surface and underground rocks and that it may be applied in defining the limits of petroleum, advanced by David White,1 has been received with keen interest by many petroleum geologists. Detailed isocarb maps have been prepared of the Pennsylvanian area of North Texas and Eastern Oklahoma by M. L. Fuller.2 A similar map of the coal-bearing area of West Virginia is given here. An isocarb3 is a line showing an equal fixed-carbon percentage, pure coal basis; the term has been proposed by David White to supersede a less expressive nomenclature. The term carbon ratio is applied to the percentage of carbon in pure coal after water and ash have been eliminated. As a comparatively small number of analyses have been made on this basis, it is usually necessary to compute the ratio by dividing the fixed carbon of the proximate analysis by the sum of the fixed carbon and volatile matter of the same analysis. Many thousands of proximate analyses have been made by the West Virginia Geological Survey, covering nearly every county in which coal is found. Numerous others have been made by the. U.S. Geological Survey and the U. S. Bureau of Mines, but as uniformity of results is

Jan 2, 1921

By J. E. Chilton

The Bureau of Mines has examined the operation of an oxygen sensor manufactured by the City University, London, England. The sensor produces a current proportional to the oxygen concentration by reacting oxygen at a nonconsumable cathode. The sensor design is unique in that the primary mode of oxygen transport to the cathode is by diffusion through a capillary, The sensor using this design has a stability of 0- to 0.02-pct reading change per day over a 4.7-month test, small temperature coefficient of 0.29-pct reading change per °C, and small pressure coefficient of 0.34-pct reading change per 1,000-ft altitude change, If this sensor were incorporated into an oxygen detector or monitor, this would be a distinct improvement in electrochemical-type oxygen analyzers and would be useful to the mining industry.

Jan 1, 1983

By Firkin GR, Allen RJ

Sulphide Corporation Pty. Limited has roasted a number of different zinc sulphide concentrates on its sinter machine which pro- duces zinc-lead sinter for an Imperial Smelting Furnace, and results have varied widely. The differences are considered to be functions of !concentrate particle size and reactivity. Amdel have used differential thermal analysis to examine these concentrates and two major effects have been found. Firstly, in concentrates 1containing small quantities of pyrite and chal- L [copyrite, heat is liberated at 400¦C to 650¦C [by oxidation of these two sulphides. Secondly, as particle size decreases, heat release from the oxidation of zinc sulphide commences at flower temperatures and rate of heat release In a sinter bed, the presence of some rite and chalcopyrite would help to heat the cc sulphide to ignition temperature in a orter time, while a finer concentrate would sult in roasting being completed more ickly. Both of these effects result in a arper flame front and minimise the chance heat and combustion fronts being mismatched. is theory is supported by sintering results tained by Sulphide Corporation. As a result

Jan 1, 1975

By Jr. Chesson

"Phosphate" is a misnomer as often used. The word is increasingly used to refer to any material containing phosphorus - an element essential to any form of life. Phosphate rock, a mineral - fluorapitate - is recovered from Florida's sedimentary deposits in particle sires ranging from 0.1 to 13.0 millimeter. This product of mining, washing, screening, and flotation is commonly called "phosphate". Its phosphorus content, measured and reported as P2O5, varies from 29% to 35%, and is essentially insoluble. "Phosphate" is also used to describe products containing soluble phosphorus obtained from acidulation of phosphate rock with mineral acids; primarily, sulfuric acid. Many miners have nearby chemical plants wherein phosphate rock is converted into upgraded products such as phosphoric acid, superphosohates, and ammonium phosphates with 45% to 70% P205, soluble and suitable for use as fertilizer. The rock and upgraded products are all commonly called "phosphate"; the plants, "phosphate plants' and the producers collectively are known as the "phosphate industry". The public in Central Florida generally loses identification of the individual operators that include major corporations such as IMC. Williams Companies, W.R. Grace, Mobil, Embark, U.S. Steel, Borden, American Cyanamid and others. They all become just a "phosphate company".

Jan 1, 1978

By R. Robertson

Dense medium cyclones are the preferred means for cleaning 112 in. x 14 Mesh to 28 Mesh (12.7 mm x 1.0 mm to 0.6 mm) raw coal and are becoming a common choice for cleaning raw coal from a nominal top size of 2-1/2 in. to 3 in. (63.5 mm to 76.2 mm) down to 14 Mesh to 28 Mesh (1.0 mm to 0.6 mm). During the last ten years, dense medium cyclone circuitry design has undergone changes which have combined to improve process efficiency. This paper describes these improvements and compares present day design with the design used prior to the mid 1980's. Improvements in the following areas are described: Raw coal desliming, cyclone configuration, drain and rinse applications, dilute medium circuitry, and instrumentation and control.

Jan 1, 1997

By T. W. Peterson, J. W. White, E. E. Krist

In developing a minicomputer application for an industrial grinding circuit, the control program is usually coded and the compilation is debugged on a remote access computing system. Final debugging must wait for installation of the minicomputer. This work reports on an alternative. Here both compilation and execution bugs are eliminated before the hardware is installed by testing the control program against a dynamic simulation. Attention is directed toward development of a particular real-time control program for an industrial wet grinding circuit in a copper concentrator. Specific data were supplied by the Anamax Mining Co. for a grinding division consisting of a rod mill followed by two ball mills in parallel. This information was used to set up a plausible model structure.

Jan 1, 1977

By M. H. Pilkuhn, H. Rupprecht

The junction luminescence of GaAsxP1-x diodes containing up to 47 pct Gap was studied. Diodes were prepared by diffusing zinc into n-type material which was eithw boat- or vapor-gvown. Observations concerning the energy and the line shape of the spontaneous emission are presented and discussed; in particular the influence of inhomogeneous phosphorus distribution is considered. The role of reabsorption of the junction radiation is pointed out. With increasing current, the peak emission shifts to higher enwgy. This is alm true in cases where slow line narrowing occurs simultaneously. The length dependence of the threshold current density for lasing at 77 °K was examined for lasers made from the same material. It was found that longer lasers have lower threshold curvent densities, Estimates of the characteristic laser losses are given. Data concwning the range of Gap concentration in which stimulated emission was observed are presented. FORWARD-BIASED p-n junctions in mixed alloys of GaAsxPl-, emit light whose wave length depenfs on the composition of the alloy ranging from 8400A (x = 1) to 5350A (x = 0) at 77°K. Laser action in vapor-grown material was first reported by Holonyak and evacqua,' and in boat-grown material by Ainslie, Pilkuhn, and Rupprecht.' In both cases this was observed for low Gap concentration where GaAs,Pl-, is still a "direct" semiconductor with the lowest conductance-band minimum at k = 0 and a subsidiary minimum in the [loo] direction. As the Gap concentration is increased, the subsidiary [loo] minimum in the conduction band is lowered and finally becomes the lowest minimum for Gap concentrations above 50 pt,3 making the alloy an ''indirect" semiconductor. It is of interest to determine up to which Gap concentration stimulated emission can be observed. EXPERIMENTAL Boat-grown material was prepared by N. Ainslie of IBM by horizontal Bridgman technique. The material was n type and silicon-doped up to a concentration of 10'' cm-'. Vapor-grown material was made by E. Hull of IBM or received from Merck & Co. Diodes were fabricated in a similar manner as in the case of GaAs by zinc diffusion. Details about the diffusion can be found in a later paper.4 All diodes were of Fabry-Perot structure with two parallel sides cleaved and the other two sides sawed. Their width ranged from 50 to 150 p and their length from 50 to 700 p. RESULTS AND DISCUSSION Spectral Distributions. A typical display of the junction luminescence of a GaAsxPl-, diode is shown in Fig. 1. The liquid-nitrogen and room-temperature curves which were taken at a very low current (25 ma dc) show a relatively sharp high-energy emission which is band-edge radiation. They also show a broad low-energy emission which is due to transitions to deep impurity levels. This latter emission line may have different shapes and positions depending on the nature of the material. It can sometimes be quite near the band gap giving rise to "bumps" in the high-energy line. The results presented in this paper will be concerned only with the high-energy emission which becomes more intense relative to the low-energy emission when the current is increased and the temperature is lowered.

Jan 1, 1964

In December's marketing of 99.5 percent aluminum ingot, domestic producer pricing remained at 53$ per pound, while dealer quoting rose from 47.5¢ to 48.5¢. BORON Domestic production of boron minerals and chemicals reached an all-time high in 1977--1.4 million short tons valued at $236 million. Combined sales of the three California producers topped the 1976 level by 15 percent in quantity and 28 percent in value, a consequence of healthy demand in the glass and insulation industries. Unprecedented demand for boric acid as a flame retardant for cellulosic insulation stimulated producers to utilize fully all available capacity, thereby achieving a record output of 158,000 tons. One company increased output from its existing boric acid facilities and initiated production at another plant that historically had produced only sodium borates. A second company achieved a previously planned 25 percent plant expansion.

Jan 1, 1978

By J. M. Oblak, W. A. Owczarski

A cellular appearing recrystallization product formed by annealing a cold-worked nickel-base super-alloy at 1800°F has been studied by electron nzicroscopy. Prior to deformation, an equilibrium micro-structure of fcc matrix y and cuboidal ,,', Ni (Al, Ti), precipitates of CuzAu structure had been established by an age at 1825°F. The strain-free recrystallization cells consist of very large rodular y' particles in a y matrix. They precipitate is oriented and coherent both before and after recrystallization. The results showed that y' coarsening accompanies recrystallization at 1800°F. However, it does so as a secondary effect and does not necessarily take place at lower temperatures. The structural similarity of this reaction to cellular precipitation in other systems indicates that lattice strain may also play a significant role during some cellular precipitation reactions. THERE have been numerous microstructural investigations of recrystallization in single-phase materials but two-phase systems have received much less attention. The second phase can either remain inert or be altered along with the matrix during recrystallization. If the second phase is an oxidelm3 or a relatively inert pre~ipitate,~, recrystallization is retarded when the interparticle spacing is less than 1 p. Prior to the onset of recrystallization, these materials show a well-polygonized substructure with the subgrain size limited by the interparticle spacing. Since recrystallization by the motion of preexisting grain boundaries6 is not observed, retardation has been related to particle pinning of the subboundaries. This pinning prevents coalescence' or growth8 of subgrains to a critical size (formation of a high-angle boundary) necessary to initiate recrystallization. In a material such as a nickel-base superalloy both y matrix and y' precipitate are altered by the recrystallization reaction. Haessner et al.' studied the recrystallization of a cold-rolled Ni-Cr-A1 alloy by electron microscopy. The material was initially cold-rolled in the supersaturated condition. upon annealing at 750°C, immediate precipitation of 7'occurred. Presence of this 7' greatly retarded the onset of recrystallization which eventually took place by the development of randomly oriented, strain-free grains. The original •/ was dissolved at the recrystallization interface and reprecipitated as oriented, coherent par-tiles in the new grain. Recrystallization caused a refinement of .)' particle size. Recently ~hillips'' investigated recrystallization of Ni-12.7 at. pct Al. Reduction by cold rolling presumably elongated the p' precipitate into lamellae that remained coherent with the matrix. After recrystallization at 600" to 750°C, there was no unusual change in y' particle size al- though there was a tendency toward clustering along the prior rolling direction at 750°C. Above 750°C, the recrystallized grains were generally free of precipitate. Studies in the somewhat analogous Cu-3.23 wt pct CO" and Cu-2 wt pct'2 systems demonstrated that the coherent cobalt-rich fcc precipitate in these alloys obstructed softening, initiation, and completion of recrystallization. The precipitates were deformed into lam~llae during rolling and those of diameter less than 250A remained coherent. Recrystallization took place by the growth of new grains into the recovered or poly-gonized material. In the first study," both matrix and precipitate reoriented in the same manner upon passage of the recrystallization interface. There was no change in particle size or morphology. Tanner and ~ervi,~ on the other hand, observed that motion of the recrystallization fronts was strongly hindered by the pinning action of coherent precipitates in the deformed material. Particles in contact with a pinned boundary coarsened and coalesced leaving a denuded zone in the unrecrystallized region. When the number of pinning points was sufficiently reduced by coalescence, the boundary swept past these particles and through the denuded zone. The authors1' considered this as a variation of discontinuous precipitation with both chemical driving force and deformation strain energy contributing to recrystallization. Preliminary observations by the present authors had revealed that recrystallization in Udimet 700, a nickel-base superalloy, occurred in an entirely different manner. Optical metallography showed that the recrystallized product formed as cellular colonies containing coarse y' particles elongated in the direction of cell growth. In this investigation the structural features of this reaction were investigated by transmission electron microscopy. EXPERIMENTAL PROCEDURE As-received I$-in. rounds of Udimet 700* were (wtpct) 18.4 15.2 4.95 4.42 3.43 0.06 0.031 0.14 Bal. solution-annealed for 4 hr at 2150" and then fast air-cooled. An initial y-~' structure was established by a 4-hr age at 1825°F followed by a fast air,cool. Essentially the equilibrium volume fraction of ?' at 1825°F is precipitated within 4 hr. Microstructural examination showed no measurable increase in the amount of precipitate after longer aging times. Deformation consisted of swaging to 52 pct RA with 6 pct reduction per pass at room temperature. To reduce the precipitation potential to a negligible amount, recrystallization anneals were conducted at 1800"~ (982"~). Microstructures were investigated by optical and transmission electron microscopy. To prepare foils for electron microscopy, the material was first sliced into 30-mil slabs parallel to the swaging direction. Discs were dimpled and electrolytically cut from

Jan 1, 1969

By Howard G. L

The gold treatment plant of Great Western Consolidated N.L. is at Bullfinch, Western Australia, 22 miles north of Southern Cross, which is 100 miles west of Kalgoorlie. A railway to Southern Cross connects the mine with the main Perth-Kalgoorlie line.The plant, which commenced operations on the 31st October, 1952, was, designed by Messrs. Alex: Stewart & Co. in consultation with the technical staff of Western Mining Corporation Ltd. to treat 1,000 long tons a day, made up of approximately equal parts of quarry oxidized ore and underground sulphide ore, by moderately coarse grinding (2-3 per cent plus 65 mesh Tyler) and straight cyanidation without straking. The design had to allow for future treatment of all sulphide ore at the rate of 40,000 tons per 28-day periodand to make provision for the possible later inclusion of preaeration treatment.The test work on .which design was based was done on representative development samples, the mine being divided into zones for this purpose, to check possible local variations from average treatment behaviour. Proposed mill feed mixtures were made up from time to time for complete ore dressing tests, which were conducted in the Western Mining Corporation laboratory at Kalgoorlie.The chief feature of the design was that the plant had to handle the extremes of very soft, poor settling and filtering oxidized ore and very hard, good settling and filtering sulphide ore. On one hand, crushers and mills had to be large enough to handle the sulphide ore and on the other, thickeners and filters had to be large enough to handle the oxidized ores.The design is marked by simplicity, the use of large units of equipment, and flexibility to cope with a variety of ores.

Jan 1, 1956

By Stanley W. Ivosevic

Introduction Increasing investor and industrial demand for gold is not being matched by new mine output from traditional sources. This forces the exploitation of alternative natural and industrial resources to supplement traditional sources. A traditional natural resource is either high- to medium-grade ore, of gold or silver with coproduct gold. Or, they are medium- to low-grade base metal ores having byproduct gold. Traditional ores are also frequently extracted at relatively great expense by selective underground mining. Alternative natural resources include low-grade, near surface ores and the products of mining-dumps - and of onsite processing - tailings. Traditional industrial resources are newly mined gold or that obtained from plant sweepings. Their alternative analogues include gold in old scrap and chemical sludges and precipitates, notably those incidental to the electronic industry. These alternative gold resources have several attractions. They are untapped and abundantly available. Having been overlooked by prior metals suppliers, title to many alternative resources is easily acquired. Or, the value of such a resource may go unnoticed until its gold is rendered exploitable by an advance in extractive technology or an other approach. This article addresses the effect of large tonnage, low-grade lode ores on gold supply. Exploiting these ores is rendered commercial by their amenability to bulk mining by modern large-scale mining and metallurgical operations requiring little selectivity. Placer gravels, perhaps the earliest type of gold ore mined, also are bulk minable. But these fall outside the definition of being lode deposits. Most lode bulk mining is from surface open-pit mines. Some, however, is from underground by such large-scale mining techniques as room and pillar, vertical crater retreat, and end slicing. The low-grade gold ore being discussed averages 2.8 g/t (0.082 oz per st). Output How greatly do bulk minable, low-grade resources effect supply? 1982 was a somewhat healthy year for gold mining and exploration in North America in spite of the general depression in the mining industry (Table 1). The wildly fluctuating price of gold bullion had stabilized at an annual aver¬age of $12.08/g ($376 per oz) - (Handy and Harmon base price). Half of the 1.3 kt (43 million oz) of 1982 world gold mined were from South Africa's high-cost, medium-grade, selective underground mines. Of the remaining half, 20%, or about 130 t (4.2 million oz), was mined in North America. This includes Canada and the US - the third and fifth largest gold producers in the world. Of that North American production, more than 62.2 t (2 million oz) of gold, or about 50%, came from bulk mining of gold ores with or without co-product silver. Most of this was in the US, where bulk minable gold-silver lode ore produced nearly 31 t (1 million oz). This amounted to 60% of the nearly 46.6 t (1.5 million oz) produced in the US during 1982. An additional nearly 7.7 t (250,000 oz) of gold were produced as the byproduct of bulk mining of cop¬per ore, for a total of 34 t (1.1 million oz) of gold, or 75% of US gold production by bulk mining. To further illustrate this, US placer, mine dump, and related operations produced an insignificant 4% of US gold output at the time. Exploitation of bulk minable gold deposits is becoming increasingly important worldwide. Most new Australian gold mining announcements are of bulk minable developments. This trend will increase in North American mining as more large tonnage, low-grade operations come onstream in Canada, where much current production is from underground. It will increase with the general climb in Mexican gold mining. And it will grow with expansion of the 12 t/a (400,000 oz per year), gold production of the Dominican Republic. Production Metal price and operating costs make these large tonnage, low-

Jan 11, 1984

By J. K. Stanley, R. F. Meel

The recrystallization of cold-worked metals is studied ordinarily by determining the temperatures required for complete recrystallization to occur within a given arbitrary time period, usually within 15 min. to 2 hr. The results obtained are conventionally assembled in a three-dimensional diagram relating this temperature to the amount of cold-work (percentage deformation) and the resultant grain size, though sometimes other modes of representation are emp1oyed.l Such three-dimensional diagrams are not complete, for the number of variables exceeds the number represented. The process of recrystallization is characterized by a time-rate, a fact that is not portrayed upon ordinary recrystallization diagrams. It is known that recrystallization consists in the formation of new nuclei and the growth of these nuclei, a process that continues until the matrix is completely consumed and the original set of grains entirely replaced by the new. This knowledge is old.2 Truly heterogeneous reactions invariably proceed by nucleation and growth; the decomposition of eutectoid solid solutions provides an example about which much is known,3 and freezing, originally studied by Tammann, provides the classic example. Although recrystal- lization is not a heterogeneous reaction within the orthodox meaning of the term, the mechanism of the process is the same. As in eutectoid inversion and freezing, it should be possible to study the rate of isothermal recrystallization as a function of time, and it should also be possible to analyze the isothermal reaction curve into the component rates of nucleation and growth that determine them.* Other methods, not employing the rates of nucleation and growth, have been used to represent the rates of such reactions, but these in general have been artificial and have not led to progress. 4,5 The theory of recrystallization is not in advanced state; if recrystallization data were obtained in terms of the rate of isothermal recrystallization, and in terms of the rate of nucleation and the rate of growth of recrystallized grains, and in particular if the temperature coefficients of these rates were measured accurately, an adequate theory should be more readily developed.27 Such an effort requires proper experimental technique, but especially requires suitable methods of mathematical analysis to convert mcasurements made upon a surface of polish into values for the rate of nucleation and the rate of growth and to combine these into a rate of isothermal recrystallization. These methods are now available for the case of three-dimensional recrystallization (recrystallization of

Jan 1, 1942

By R. F. Meel, J. K. Stanley

The recrystallization of cold-worked metals is studied ordinarily by determining the temperatures required for complete recrystallization to occur within a given arbitrary time period, usually within 15 min. to 2 hr. The results obtained are conventionally assembled in a three-dimensional diagram relating this temperature to the amount of cold-work (percentage deformation) and the resultant grain size, though sometimes other modes of representation are emp1oyed.l Such three-dimensional diagrams are not complete, for the number of variables exceeds the number represented. The process of recrystallization is characterized by a time-rate, a fact that is not portrayed upon ordinary recrystallization diagrams. It is known that recrystallization consists in the formation of new nuclei and the growth of these nuclei, a process that continues until the matrix is completely consumed and the original set of grains entirely replaced by the new. This knowledge is old.2 Truly heterogeneous reactions invariably proceed by nucleation and growth; the decomposition of eutectoid solid solutions provides an example about which much is known,3 and freezing, originally studied by Tammann, provides the classic example. Although recrystal- lization is not a heterogeneous reaction within the orthodox meaning of the term, the mechanism of the process is the same. As in eutectoid inversion and freezing, it should be possible to study the rate of isothermal recrystallization as a function of time, and it should also be possible to analyze the isothermal reaction curve into the component rates of nucleation and growth that determine them.* Other methods, not employing the rates of nucleation and growth, have been used to represent the rates of such reactions, but these in general have been artificial and have not led to progress. 4,5 The theory of recrystallization is not in advanced state; if recrystallization data were obtained in terms of the rate of isothermal recrystallization, and in terms of the rate of nucleation and the rate of growth of recrystallized grains, and in particular if the temperature coefficients of these rates were measured accurately, an adequate theory should be more readily developed.27 Such an effort requires proper experimental technique, but especially requires suitable methods of mathematical analysis to convert mcasurements made upon a surface of polish into values for the rate of nucleation and the rate of growth and to combine these into a rate of isothermal recrystallization. These methods are now available for the case of three-dimensional recrystallization (recrystallization of

Jan 1, 1942

By N. Afrin

The microstructure and tensile properties of AZ31B-H24 magnesium (Mg) alloy after friction stir welding (FSW) were evaluated. The grain size was observed to increase from approximately 5 µm to about 9 µm after FSW. The obtained Hall-Petch type relationship showed a strong grain size dependence of the hardness values. While the FSW led to about half of the yield strength of the base magnesium alloy, the ultimate tensile strength after FSW could reach about two thirds of that of the base alloy. The hardening capacity of the FSWed samples was about twice of that of the base alloy. The strain hardening exponent of the base alloy was found to be about 0.1 whereas it became larger than 0.3 for the FSWed samples. After yielding the base alloy showed a high initial and almost constant work hardening rate, corresponding to linear hardening stage II, followed by stage III with a decreasing hardening rate. Stage II linear hardening was observed to be absent in the FSWed samples.

Jan 1, 2007

Completing its historical role the opera tion of copper blast furnace of the Saganoseki Smelter was terminated in 1970, but it left some interesting data on metal lumps formed at the furnace bottom. Analysis disclosed the lumps to be speiss containing 100 to 10,000 g/t of Au and Ag and stratified to iron speiss and copper speiss. Solidifying temperatures of iron speiss and copper speiss being approximately 1,090¦C and 800¦C respectively, copper speiss precipitated at the lower side. The distribution coefficient of Au and Ag between matte and speiss (g/t Au(Ag) in matte / g/t Au(Ag) in speiss) is in the range of 1 x 10 2 to 2 x 10 ' and 1 x 10 1 to 5 respectively. The higher Cu % is in speiss, the-more An and Ag are distributed into speiss. Except for a few data, these results comfotm well to the range of distribution equilibria of Au and Ag in matte and speiss systems by Gerlach and Others.

Jan 1, 1980

By B Darlington, L Sandberg, O Vallati

The D47 and D39 Mechanical Dynamic Extra bolts (D47 MDX and D39 MDX) have been developed in response to the ever-increasing demand from the mining industry for rock bolts with high dynamic capacity. To prove such capacity, Sandvik has performed numerous in situ dynamic testing with the unique Dynamic Test Rig (DTR) (Darlington, Rataj and Roach, 2019; Roach, Rataj and Darlington, 2019). To complement the collection of testing data, Sandvik, in collaboration with the Swedish Research Institute for Mining, Metallurgy and Materials (Swerim) have performed additional experiments in laboratory condition using Swerim’s new drop test rig. This rig utilises a momentum transfer method to apply a dynamic load to the bolt. The sample falls together with the mass until the support beam impacts stationary dampers and the momentum energy is transferred to the bolt. Part of the charged energy is released by the dumpers while the remaining portion is absorbed by plastic deformation and/or displacement of the ground support element. The D47 and D39 MDX bolts have been tested at Swerim’s test facility with different levels of input energy. Six tests were performed at the specification energy of 36 kJ and six tests were carried out with the maximum allowable energy from the facility, ie 44 kJ. The bolts confirmed their dynamic performance absorbing the input energy without failure. The D47 MDX bolt absorbed up to 33 kJ with 150 mm displacement while the D39 MDX bolt absorbed up to 35 kJ with 162 mm displacement. This work will present an overview of the drop test rig at Swerim’s facility and a collection of results of the test performed on the D47 and D39 MDX bolts. The test method and results will be analysed and compared to the tests carried out with the in situ DTR.

Nov 29, 2022

By James Hall

A geological map of a State involves very much, and its pre sentation to the public incurs grave responsibilities. It has been for a long time my earnest desire to bring out and place before the pub lic a geological map of New York which might be creditable to the State and worthy of a place among her scientific publications. We have done much for the advancement of geological science in this State—very much, and in many directions—but unfortunately, this feature, which should have been made the basis of all our work, has been too long neglected and delayed. For twenty-five years I have been laboring and looking forward to this consummation. I have recorded the field-work, systematic and desultory, upon such maps as were available for this use; and notwithstanding their imperfec tion, I have been able to transfer this recorded information to a more perfect base, which it is hoped will be completed during the early months of the next year. In 1883 I had combined, upon a small map of the State, the in formation which we possessed at that time, and communicated the same with my annual report to the Legislature. The report mas published in the regular course, but the special appropriation made for the map was vetoed by the Governor. Not discouraged by this untoward and unexpected circumstance, I continued my work, and made every effort to render the map more complete, preparatory to its communication with the next annual report. I brought together all the information within my reach, whether published or unpublished, reviewing and revising, as far as practicable, the work done by myself and assistants in southern and southeastern New York.

Jan 1, 1893

By Harold Gibson, Ulrich Schwarz-Schampera, Ralf Freitag, Hendrik Mueller

INTRODUCTION Germany has a long history in marine research in the Indian Ocean. The first German scientific cruise started in 1964, followed by a series of state-sponsored research cruises between 1983 and 1995 leading to the first finding of polymetallic sulfides in the Indian Ocean. The research included regional bathymetric, geological, structural, volcanological, petrological and hydrothermal investigations along the Carlsberg Ridge and the Central Indian Ridge (CIR). Early environmental base line studies covered oceanographic and sedimentology aspects. In 2010, BGR took the initiative for the preparation of a license application for the exploration of polymetallic sulfides with the International Seabed Authority (ISA), and prospecting started in 2011 along the southern Central (CIR) and the northern Southeast Indian Ridge (SEIR) in the southwestern Indian Ocean (cruises INDEX 2011 on board R/V Sonne), INDEX 2012 (R/V Fugro Gauss), INDEX 2013/1-2 (R/V Sonne) and INDEX 2014 (R/V Pelagia). After three years of resource-oriented and environmental base line studies, BGR, in order for the Federal Ministry for Economic Affairs and Energy (BMWi), applied for an exploration license which was approved by and subsequently signed with the ISA in 2015. The license gave permission to start a detailed exclusive resource-oriented exploration program in the license area. The program includes the outline of potential ore deposits and a resource assessment but also extensive and detailed base line studies for the sustainable protection of the marine environment in the license area. The license contract has a fifteen years lifetime and may allow the application for a subsequent mining license. The exploration aims at the identification of inactive polymetallic sulfide deposits, formed below former discharge zones of hot hydrothermal fluids on the ocean floor (“black smoker” systems), by advanced and modern exploration techniques.

Jan 1, 2018