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By C. H. North, L. E. Lynd, W. W. Anderson, H. Sicurdson

Since the composition and structure of the beach sand concentrates correspond so closely to what would be expected of ilmenites that have been altered by oxidation and leaching, there is no reason to postulate the existence of the hypothetical compound, arizonite, to account for the composition of titaniferous beach sand concentrates. The four concentrates studied are examples of the different products that can result from various degrees of alteration of primary ilmenite. CONSIDERABLE uncertainty is revealed in the literature regarding the nature of the titanium minerals which make up the bulk of the heavy, opaque fractions of numerous beach sand deposits of the world. An investigation was made, therefore, of beach sand concentrates of North Carolina, Florida, Brazil, and India. Magnetic concentration, X-ray, and microscope data were obtained which show that these concentrates consist essentially of ilmenite and its alteration products. The alteration, brought about by oxidation and leaching of iron values, has resulted in upgrading the ores to a range of 56 to 64 pct TiO², as compared with 52.7 pct in ilmenite of theoretical composition. Conclusions drawn regarding the nature of the dominant titanium-bearing mineral in beach sand deposits have been based mainly on chemical composition, specific gravity, and petrography. This material has usually been referred to as ilmenite or weathered ilrnenite.: It has also been referred to as arizonite because in chemical composition it resembles an Occurrence in in which was described by Palmer' in 1909. The chemical composition of Palmer's arizonite corresponded closely to the formula Fe²O³ . 3TiOs. From approximate measurements of crystal angles on a large imperfect crystal with rounded faces, the

Jan 1, 1955

By G. Sachs, L. J. Ebert, W. F. Brown

INTRODUCTION ISOTHERMAL transformation, or "austempering," of a carbon-containing austenite at elevated temperatures yields so-called "intermediate products." Their structure and properties are, for a given hardness, rather different from those of "tempered martensite" obtained on conventional quenching and tempering.1 Several investigators2,3 have found that for high carbon and slightly alloyed steels the intermediate products formed at temperatures close to that of the martensite reaction possess strength properties superior to those of tempered martensite. The structure of these low temperature, intermediate products is generally acicular (bainite) but clearly different from that of martensite. However, at higher austempering temperatures, between 1000 and 1300°F (540 and 700°C) carbon steels were found to exhibit a rather low ductility.4-5 Thus notch bar tensile tests showed the ratio between notch strength and regular tensile strength to decrease with increasing austempering temperature. For ductilities below a few percent this notch strength ratio is a measure of ductility, according to investigations on low alloy steels.6-7 Furthermore the presence of intermediate products formed unintentionally on quenching was considered as responsible for the low ductility and impact energy of some heat treated steels.8 These intermediate products could result from partial transformation at the so-called "nose-temperature" where the rate of the transformation is a maximum. Tempering improved such mixtures of martensite and intermediate products, their properties approaching those of tempered martensite of equal hardness. The following investigation constitutes an attempt to determine certain strength properties of a partially austempered and subsequently quenched low alloy steel, namely, a chromium steel (SAE 5140). The structures formed by such a treatment should consist of a mixture of intermediate products formed on austempering and a martensite formed on oil quenching from the austempering temperature. It was intended, by varying the austempering time, to vary the quantity of the intermediate products between zero and 100 pct. The austempering temperature of 860°F was selected after extensive preliminary tests close to the nose-temperature. Austempering at this temperature yielded an acicular intermediate product. Additional tests under less exacting conditions were made for an austempering temperature of 950°F where the intermediate product appeared to be very fine pearlite. To determine the effects of tempering on structures containing various amounts of

Jan 1, 1948

By Charles B. Dudley

In view of various papers and discussion.;, at recent meetings of the Institute, upon testing, methods of testing, inspectors, inspection and specifications, it has occurred to me that my experience of some fifteen years, in the making and enforcement of specifications, in connection with the Motive Power Department of the Pennsylvania Railroad, might give some value to the few suggestions offered in this paper. There is friction, not to say antagonism, between the producers and the consumers of structural materials. On the one hand, the producers complain of the severity of inspection, or the lack of knowledge and want of good judgment on the part of inspectors, and, indeed, have gone so far as to suggest the abolition of the whole scheme of inspecting and testing materials. On the other hand, the consumers are, apparently, more and more relying on specifications

Jan 1, 1893

In March 1962, over three months ahead of schedule, production began from the Ventersdorp Contact Reef of the Western Deep Levels Ltd. mine on the West Witwatersrand. Few mines have captured the interest of mining men and the public as has Western Deep Levels. It has presented the gold mining industry with a challenge which involved the opening of an ultradeep mine with the attendant problems of exceptionally heavy capital commitments ($77 million to start of production), high rock temperatures and pressures at great depths, cementation and pumping in an area notorious for the volume of subsurface water, and the necessity for entirely new thinking and the application of new ideas. HISTORY Not all the problems facing Western Deep Levels were, however, new. Situated 43 miles from Johannesburg, just off the main road to Potchefstroom, Western Deep Levels was the sixth company to undertake mining operations on what is known as the West Wits line and it could draw on the wealth of experience gained by other pioneer mines in the area.

Jan 12, 1962

By N. C. Nissen, J. A. Thomas, A. Illis, K. N. Subramanian

Successful miniplant and laboratory testwork has indicated that high purity selenium can be produced from copper refinery slimes. The recovery technique fits into existing unit operations, and the selenium recovery in the new process was close to 99%. This recovery virtually eliminated any selenium being processed through the smelting stage. In addition, miniplant tests conducted at Inco Metals Co.'s J. Roy Gordon Research Laboratory in Mississauga, Ontario, have demonstrated the reliability of the process with respect to extractions, product quality, filtration characteristics, and effluent disposal. Inco's copper refinery at Copper Cliff, Ontario, produces about 500 t/d of copper with the anode slimes fall typically averaging 0.5% of the throughput. Investigations relating to the treatment of slimes within Inco's R&D have been conducted on several occasions since 1959, when the available alternatives such as acid or alkaline pressure leaching, aqueous or high temperature chlorination, roasting, smelting, etc., were considered. Interest in slimes processing was revived recently to meet increasingly stringent environmental standards and to replace equipment of a relatively old plant.

Jan 11, 1978

By P. Nicholls

Though the burning of fuels extends far back into antiquity, and though fuel beds are the most common and widely distributed example of chemical actions and engineering practice, there has been little attempt to group fuel beds by types or to define the principles associated with them. This paper does not profess to cover completely the subject of fuel beds. It suggests some of the over-all principles of the two more common types. No new investigational data are included, but the deductions are largely based on a recent publication of the U.S. Bureau of Mines'. Definition of Types There are three primary types of fuel beds: (I) Underfeed, in which the fuel and the air move in the same direction; (2) overfeed, in which the fuel and the air move in opposite directions; (3) crossfeed, in which the fuel and the air move at right angles to each other. The principle that fixes the type is the relation between directions of the flow of fuel and of air. Fig. 1 shows the three types diagrammatically. All other types are compounded of these three in a simple or more or less complex manner. It does not follow that these three type designations are limited to the methods used in representing them in Fig. 1; they may be turned in any direction, and as long as the relative directions of the fuel and air are the same the type is not changed. For example, A as shown .resembles a pot-type stoker, but the air and fuel can move downward as in the so-called smokeless heating boiler furnace. Also, C can be placed horizontal, as in chain-grate stokers. For this reason, the terms used to designate the three types are not all that could be desired; more logical ones could be coined, but those used probably are satisfactory until the discussion of fuel-bed types becomes more common.

Jan 1, 1936

By P. Nicholls

Though the burning of fuels extends far back into antiquity, and though fuel beds are the most common and widely distributed example of chemical actions and engineering practice, there has been little attempt to group fuel beds by types or to define the principles associated with them. This paper does not profess to cover completely the subject of fuel beds. It suggests some of the over-all principles of the two more common types. No new investigational data are included, but the deductions are largely based on a recent publication of the U.S. Bureau of Mines'. Definition of Types There are three primary types of fuel beds: (I) Underfeed, in which the fuel and the air move in the same direction; (2) overfeed, in which the fuel and the air move in opposite directions; (3) crossfeed, in which the fuel and the air move at right angles to each other. The principle that fixes the type is the relation between directions of the flow of fuel and of air. Fig. 1 shows the three types diagrammatically. All other types are compounded of these three in a simple or more or less complex manner. It does not follow that these three type designations are limited to the methods used in representing them in Fig. 1; they may be turned in any direction, and as long as the relative directions of the fuel and air are the same the type is not changed. For example, A as shown .resembles a pot-type stoker, but the air and fuel can move downward as in the so-called smokeless heating boiler furnace. Also, C can be placed horizontal, as in chain-grate stokers. For this reason, the terms used to designate the three types are not all that could be desired; more logical ones could be coined, but those used probably are satisfactory until the discussion of fuel-bed types becomes more common.

Jan 1, 1936

By A. B. Kinzel

ALTHOUGH vanadium is an important constituent of almost every brand of high-speed steel manufactured today, little is known as to its role in this series of alloys. The now standard 18 per cent tungsten and 4 per cent chromium constituents were the result of developments and improvements before 1903. In that year, vanadium was added to the steel by Dr. J. A. Mathews. This proved to be an outstanding con-tribution, so that the standard high-speed steel of today is generally referred to as the 18-4-1 type-18 per cent W, 4 per cent Cr and 1 per cent V. Various modifications have been attempted, since then, but with the exception of the introduction of cobalt, no striking improvements have occurred. Vanadium has been increased to 2 per cent in many of the common brands, and at least one brand contains 5 per cent V in addition to the usual tungsten and chromium. The carbon has been gradually increased so that it is not uncommon to find 0.80 per cent in the standard grade, although the carbon in the 5 per cent vanadium steel mentioned above is approximately 1 per cent, and even 1.2 per cent has been made experimentally. The role of vanadium has never been well understood, and although vanadium has been increased to 2.5 and even 5 per cent in certain high speed steels, it has not been generally established that the higher vanadium contents 'result in superior cutting properties. However, in all of the investigations, of which the writers are aware, the interrelation of the vanadium and carbon contents was not considered as a prime factor. The carbon content was held at 1.2 per cent or less-generally at the usual 0.65 to 0.75 per cent.

Jan 1, 1932

By E. H. Bronson

PROPERTY of Malartic Gold Fields Ltd. is situaated in the great clay belt in the northern part of the Province of Quebec. This belt represents the floor of the glacial lake Barlow-Ojibway. The clay blanket has a gently rolling, almost flat surface, with here and there projecting knobs and ridges that outline the large irregularities of the surface on which the clay was deposited. At irregular intervals glacial eskers dominate the landscape. The ore-bearing country rock is covered by strata of clay, sand, and silt to a depth varying to 40 ft. There are serious structural problems when it is necessary to place loads of unequal intensities on this surface to support buildings and machinery for a modern mining plant. Earlier mining companies and their engineers paid little attention to the science of soil mechanics, partly because they believed it unnecessary and partly because they knew little of the subject. The results are evident in some of the tottering structures in older camps. Careful analysis of soil problems is well worth-while, since cost of foundations may vary from 20 to 50 pct of the final cost of a structure. Low operating and maintenance costs can be achieved only in this way.

Jan 11, 1957

By James Gayley

The lining of the hearth and bosh of a blast-furnace has naturally come to be considered its weakest part, being subject not only to abrasion, but also to intense chemical action. In order to provide against rapidity of wear, it was formerly customary to build the lining from the mantle to the top first, and to put in afterwards the hearth and bosh, drawing the latter into a recess that had been reserved for it in the upper lining. At some works this practice still prevails ; but through the progressive development of cooling-devices, it has become possible to protect the bosh so well as to make it the most durable part of the furnace. The main question now is, by which one out of several methods the best economy results can be obtained. The plain bosh-jacket, made of wrought-iron or steel, and frequently called the air-cooled jacket, was a great improvement over the crinoline-construction formerly in vogue; but it was difficult in many cases to persuade furnace-managers, that in order to secure its best effects, they must discard the thick bosh-walls and put in comparatively thin ones. Mr John M. Hartman, who did more perhaps than any one to extend the use of these jackets, invariably contended for a 13-inch wall, the thin wall being an essential part of this construction. Later, a coil of pipe was placed just inside the jacket, through which water, circulating freely, contributed further to the proper maintenance of the walls. Undoubtedly much better results have been obtained in practice where the iron jacket has been supplemented by a coil in this way. It is safe to say that this combination of water-coil and jacket is much better than external sprays on the jacket; but it does not prevent the brick-work from cutting entirely away, which enlarges the bosh to that extent and interferes with the economy and output of the furnace. In case of leakage or stopping-up of the pipes, they cannot be replaced. A leading blast-furnace manager who is now using this construction

Jan 1, 1893

By A. Weiss, W. A. Coster

The search for ore is characterized by a great variety of uncertainties, each of which can be resolved by obtaining information at a cost. Three exploration stages may be distinguished in which information can be obtained, based on inherently different cost structure: 1) the reconnaissance or scanning stage, 2) the examination or screening stage and 3) the project stage. This exploration sequence would roughly coincide with replies to questions as to: where, how, why and how much. As complete information in each stage is too costly to acquire, we must assess the probability that adequate information will be furnished by a limited amount of effort and attempt to maximize the expected value of ore to be found for a given exploration expenditure. Several problems are discussed relative to the mathematical formulation and possible computer procedures for determining the optimum allocation of a total exploration effort. Based on the available literature possible solutions to this problem are indicated. When scanning through published literature on mineral exploration, it seems at first that there is little room for substantial and systematic improvements in the efficiency with which the problem of discovery of new ore deposits is presently being handled by large organizations active in exploration. It appears equally difficult to offer something relevantly new which could generate a break-through in exploration thinking and cause a marked improvement in the ratio of successful undertakings to the total exploration projects started. On the other hand, a number of experts in recent years have urged that the problems in prospecting be analyzed in a more skillful and sophisticated manner than in the past. Their thesis is based mainly on the premise that the cost of finding mineral deposits will increase with increasing technical difficulties. In present large-scale exploration ventures, especially in those regions where outcrops and immediately visible geologic evidence are scarce, older methods of prospecting are increasingly being replaced by more indirect and systematic geophysical and geochemical methods with more emphasis on correct statistical design of exploration patterns. It is perhaps the oil industry which has made the greatest strides in developing statistically, well justified patterns in its search for oil; possibly because oil seepages, as indicators of the presence of oil, left off at an earlier point in time than did outcrops as indicators of base metals. Among the pioneers in the field of statistics and operations research, as applied to mineral exploration, the excellent works of Allais, Slichter, Koop-man, Mickey, de Guhnin, Krumbein, Griffith, Sichel, Krige, de Wijs, and Matheron may be mentioned. It should, however, be pointed out that three subjects of basic importance to the allocation of exploration efforts have so far received only scant attention in published literature, even by the aforementioned authors. In the first place, a more precise definition of the object of the search, i.e., a minimum-size orebody, seems to be outstanding. Secondly, a decision model is not a widely-discussed subject. Thirdly, no concentrated attempt so far seems to have been made to establish probabilities of the occurrence of economic deposits on a regional scale and to arrive at a slightly more accurate knowledge of the probability laws governing the deposition of ore. It is not the purpose of this paper to create new order in the complexity of uncertainties in which our decision processes in exploration necessarily have to be conducted. Rather, we intend to highlight some of the outstanding, hitherto unmapped territory, where diligent compilation and a utilization of present and historic data may statistically improve our chances of success. We hope that the contribution of this paper will lie in bringing allocation problems into better focus and in increasing the mineral industry's realization of the magnitude of the factors involved. THE MINIMUM-SIZE OREBODY The concept of target specifications for what constitute a minimum-size orebody in exploration is a rather variable one and depends to some extent on

Jan 1, 1963

By Steven T. Mitchell

The introduction of Vertical Crater Retreat (VCR) Stoping at the Homestake Mine in Lead, SD, constitutes a major advance in Homestake Mining Company's efforts to improve productivity and reduce costs through under- ground mine mechanization. The work to date indicates that Vertical Crater Retreat Stoping is one of the safest methods of underground hardrock mining today, and is competitive with all other forms of stoping in terms of cost and productivity. Homestake anticipates that VCR stoping will account for approximately 35% of the total mine production in 1981.

Jan 1, 1981

By N. I. Fisher, J. Shepherd

A rapid method of determining natural fracture trends in collieries has been developed. The method will yield information that is precise enough to permit fracture domain boundaries to be delineated in a coal seam. Instead of a survey of cleat trends in a colliery taking several man-weeks or even man-months, a reconnaissance survey can be carried out in only a few man-days. At each of a sequence of sampling sites along a traverse, five measurements of trend are recorded for each set of fracture directions. A sequential plot of the medians of each fracture set is then made manually underground or by a computer in the mine office. Changes in fracture pattern can be detected easily in colliery development work if a geologist visits advancing faces regularly, and forecasts can be made about the likelihood of forthcoming faults and dykes. A full description of this method is given in Shepherd and Fisher (1981). The concept of mapping fractures rapidly in a colliery is based on using a geological traverse (Compton, 1962), along which observations can be made at chosen, regular intervals. The technique has been widely used for surface mapping across outcrops and in follow-up work in photogeological studies (Hepworth and Kennerley, 1970). In these cases, the geologist surveys the traverse line as mapping proceeds. In a colliery, however, ready-made traverse lines already exist in panels and along main roadways, often in several directions. It is thus possible to traverse a colliery in different directions and record the fracture trends at intervals, generating a reconnaissance fracture map. This can also be done on a continuing basis as mine development takes place. Generally, a sampling traverse should be longer than 0.5 km with sampling sites at relatively close-spaced intervals along the traverse. For example, in room-and-pillar mines pillars are commonly formed on 40-m centers and the sampling sites can then be arranged at 20-m intervals [(Fig. 1)]. The sites might have to be closer together for mines known to have bad mining conditions. The predominant fracture trend is normally the face cleat and the subordinate trend is the butt cleat (McCulloch et al.. 1974). Various changes can occur in the cleat or joint pattern: the face and butt sets may disappear or an entirely new set or sets may appear. Therefore, it is best to record all prominent fracture sets. Sometimes there is only one; in other cases there may be as many as three or more. An odd number of measurements of each fracture set are made (generally five or more) to enable the median value to be determined easily. The median value can be plotted underground using graph paper or a computer plot can be made in the laboratory or mine office [(Fig. 2)]. The sequential linked median (SLIME) plot draws the median trend for each sampling site as a unit line segment. The segments from successive sampling sites can be connected together to form a long chain [(Fig. 2A)]. The needle plot, on the other hand, draws a straight line to represent the traverse and then plots out the median trend for each sampling site [(Fig. 2B)]. The SLIME plot is better for visual display, as it highlights small irregularities and gross changes in trend. However, some work is required to relate the individual segments to their site location along a traverse. In this respect, the needle plot is more convenient because each segment -can be plotted-at a point corresponding to its location. Also, there is precise match-up if needle plots of face and butt cleat are compared. A description and listing of the SLIME program is given by White et al. (1981). An example of the use of this method is given for Wallsend Borehole colliery in New South Wales (Australia) [(Fig. 2)], where domains II and IV are associated with mining hazards. Domain II is coincident with a normal fault of 2.6-m throw, and domain IV with a basic dyke 12 m thick. These hazards were approached driving in a southwesterly direction, and a pronounced change in trend of the cleat to a northwesterly direction occurred at a distance of approximately 45 m from each one. The northwestern joint trend is parallel to that of the dyke and fault, and it occurs at a higher frequency close to these structures. The association of a particular joint set with faults has been found elsewhere (Shepherd and Creasey, 1979). The two minor cleat direction changes within domain V are narrow joint zones that are less than 5 m wide. The fracture trends derived from a SLIME traverse can be verified by collecting larger quantities of data at selected sites, as shown in the balloon density (rose) plots depicted in [Fig. 2C]. We are grateful for the financial support provided by Thiess Bros. Pty. Ltd. and the National Energy Research, Development, and Demonstration Program administered by the Commonwealth Department of National Development and Energy. R.W. Miller Holdings Ltd. and Thiess Bros. Pty. Ltd. are thanked for their permission to publish data from their collieries.

Jan 1, 1982

By E. R. Borcherdt

METHODS and equipment are subject to study in the Butte district at all times in order that advantage may be taken of any new developments that might serve to increase efficiency and lower costs. Detailed time studies of each operation involved in the entire mining process have been of invaluable assistance in analyzing the individual operation for possible improvement. In other words, the fact that a practice has been in vogue for many years does not exempt it from change provided an easier and cheaper method can be found. EXPLORATION Ore occurs in the Butte district in such manner that structures must be drifted on, no matter how small or unimportant they appear when intersected by a crosscut. Parallel structures also add to the crosscut requirements. This prospecting work, which formerly was done entirely by drifting and crosscutting, is now being supplemented by diamond drilling, to aid in greatly decreasing the amount of waste. In long-shot prospecting, or in second or third class prospecting, where the chances of developing commercial ore are not very great, diamond drilling is of particular value. In prospecting where chances of encountering commercial ore are certain or where crosscuts can be used later for haulage or ventilation, drilling obviously is not applicable. Improvement in drilling machines and bits has contributed greatly to the present success of diamond drilling. STOPING For many years square-set filled stoping was the principal mining method used in the Butte district. Later timbered and untimbered rill stopes were used, also some horizontal cut-and-fill stoping where both ore and walls were particularly strong. Because of the amount of timber required for square-set stoping, and the relatively low production per stope unit, experiments with horizontal cut-and-fill stopes were begun in ore bodies of which many had fairly weak walls. It was felt that increase in the speed of the stoping operation, followed closely by filling, to avoid weight being produced by permitting ore and walls to remain insufficiently supported over comparatively long periods, would maintain the walls and backs in safe condition without the use of timber and without ore dilution from wall slough. Cycles of drilling, scraping ore, and filling were devised, which have materially increased stope production and decreased timber consumption, so that both stope labor and supply costs were lowered appreciably without materially affecting grade control. In the larger mines of the district, where wide veins favor this stoping method, half of the total production is now being mined by horizontal cut-and-fill stopes (Fig. I). The increase of the filling rate demanded by the increased stoping rate was the greatest obstacle encountered in the accelerated stoping operations. Finally this problem was solved by replacing the time-honored method of transferring filling waste by small cars, which were hoisted or lowered in the auxiliary shaft, by a transfer

Jan 1, 1941

By E. A. Peretti

BEFORE embarking on a detailed investigation of the system indium-antimony-bismuth, experiments were carried out to determine the existence of quasi-binary sections. The bordering binary systems are known1 and show the occurrence of three intermetallic binary species corresponding closely to InSb, InBi and In2Bi. Attention was focused on the low-indium end of the ternary diagram where the possible quasi-binary sections, excluding ternary compound formation, would involve the pairs: InSb-Bi, InBi-Sb and InSb-InBi. The latter pair revealed itself as a true quasi-binary, so it was investigated fully by thermal analysis, x-ray and microscopic examinations. All compositions were made by proper combination of three elements involved. The indium had a guaranteed purity of 99.97 pet; the antimony contained 99.99 pet Sb, and the bismuth had a purity of 99.99 pet. Alloys were made by melting together antimony, bismuth and indium in evacuated, sealed pyrex-glass tubes at a temperature of 600°C with vigorous agitation. The melts, weighing about 80 grams, were allowed to freeze in the sealed tubes and finally were transferred to glass tubes for the taking of cooling and heating curves. A protective atmosphere of helium was used, and the melts were stirred mechanically while cooling at rates of from 0.5 to 3°C per min. Temperatures were measured with a calibrated chromel-alumel thermocouple and were recorded graphically on a Minneapolis-Honeywell extended-range recorder working in conjunction with a Leeds and Northrup type K-2 potentiometer. Conventional polishing techniques gave satisfactory results in preparing specimens for microscopic examination. Etching was carried out with Vilella's reagent or aqueous mixtures of chromic oxide with either nitric acid or sulfuric acid plus dichromate. Conclusions deduced from the thermal analysis and microscopic examinations were confirmed by X-ray photograms using Co-K alpha radiation. The phase diagram is shown in Fig. 1. The liqui-dus consists of an uninterrupted line running from the freezing point of InSb (525°C) to a eutectic point experimentally indistinguishable from the freezing point of InBi (110°C). X-ray patterns of the InSb show a slight expansion of the lattice with the addition of InBi, and microscopic work indicated the solid solubility of InBi in InSb to be less than 0.5 pet at room temperature. Acknowledgment We wish to thank the Indium Corporation of America for the loan of the indium used in this investigation. References 1 E. A. Peretti and S. C. Carapella, Jr.: Trans. ASM., 1949, vol. 41, P. 947. T. S. Liu and E. A. Peretti: Trans. ASM, 1952, vol. 44, p. 539. Metals Reference Book, vol. 1, 2nd ed., AIME, p. 345.

Jan 1, 1959

By John C. F. Randolph

(Read at the Amenia Meeting, October, 1877.) Tits establishment being now in full working order, it has seemed of considerable professional interest to collect together, in a concise form, the various points as to its plan, method of dressing, and equipment. The data contained in this paper have been largely drawn from the able paper of E. Kutscher, constructing engineer. of the works, contained in the Zeitschrift fur Berg-Hütten-und Salinenuesen im Preussischen Staate, 1873, supplemented by some personal memoranda made while the works were under construction and by memoranda on the works appearing in various German technical papers from their completion up to date. This is probably the largest dressing works in the world devoted to the beneficiation of argentiferous lead ores, and it is doubtful if any establishment for the concentration of mineral of any description can compare with it in size. As showing the final practice adopted in an old and very conservative mining region, in which the concentration of ores has been a matter of constant practice and experiment for a very long period, these works are of peculiar interest. The fact that the Clausthal ores strongly resemble a very large and abundant class of ores found in the United States has always attracted the attention of American mining engineers and mine owners to the methods employed in dressing and smelting them. The study of their methods of concentration of ores has, however, always been full of difficulty,

Jan 1, 1878

By Edgar G. Hill

Much has been written and said recently about the methods used and materials and equipment employed in building the long tubes that criss-cross a great part of the United States, like the pattern of a spider's web. This paper will discuss the fundamentals of design of these lines from the economic as well as the engineering viewpoint, pointing out the effect of the volumes transported, and the load factor, on the unit costs of transportation, as well as the effects on costs of the character 01 the fluids the lines are called upon to handle. Generally speaking, crude-oil pipe lines carry oil from the producing fields to the refineries. Sometimes part of the journey is by pipe line to a coastal point and tank ships are employed for the rest of the trip. The main lines of directional flow of crude oil through pipe lines in the United States are shown on Fig. I, but this, of course, does not always show individual pipe lines. Basic Formula for Flow OF Crude Oil The laws governing the flow of crude oil through pipes are well known. The basic

Jan 1, 1942

By Edgar G. Hill

Much has been written and said recently about the methods used and materials and equipment employed in building the long tubes that criss-cross a great part of the United States, like the pattern of a spider's web. This paper will discuss the fundamentals of design of these lines from the economic as well as the engineering viewpoint, pointing out the effect of the volumes transported, and the load factor, on the unit costs of transportation, as well as the effects on costs of the character 01 the fluids the lines are called upon to handle. Generally speaking, crude-oil pipe lines carry oil from the producing fields to the refineries. Sometimes part of the journey is by pipe line to a coastal point and tank ships are employed for the rest of the trip. The main lines of directional flow of crude oil through pipe lines in the United States are shown on Fig. I, but this, of course, does not always show individual pipe lines. Basic Formula for Flow OF Crude Oil The laws governing the flow of crude oil through pipes are well known. The basic

Jan 1, 1942

By H. N. Treaftis, J. W. Cahn

THE previous determinations of the solvus of tin in solid lead disagree with one another by as much as 40°C or almost 10 at. pct. Even determinations that appear to be careful differ considerably in both the solubility and its temperature coefficient. Recent kinetic workl -3 on the rate of precipitation of tin from lead-tin alloys and thermodynamic work4 on the heat of solution of tin in lead have given some insight into the time necessary to reach equilibrium in this system. As this time is longer than that used in almost all previous determinations of the solvus, these determinations are questionable. Since the interpretation of recent kinetic results requires accurate values of the equilibrium solubility the present work was undertaken. DISCUSSION OF PREVIOUS RESULTS The methods used in previous studies may be placed into three classes: 1) Several alloys covering a range of compositions are allowed to reach "equilibrium" at a certain temperature.5-7 Some property, such as the X-ray lattice parameter of the lead-rich phase or the re- sistivity of the alloy, is then measured as a function of composition. The solubility limit for that temperature is taken to be that composition at which a discontinuity in the property occurs. However, the recent kinetic work has shown that tin precipitates in two stages. The first stage is rapid but leaves the lead still supersaturated. The second stage is very slow, and it seems from the equilibration times quoted by the investigators of the solvus that the end of the first stage of precipitation was usually mistaken for equilibrium. This is especially true at temperatures below 100°C where the first reaction is still quite rapid (from minutes to months), but where the second stage is so slow that very long holding times are required to reach equilibrium. Alternatively micrographic work8 on several alloys of different compositions seems to have given good results if done carefully. 2) The beginning of precipitation in a homogenized alloy is measured as it cools slowly8-10. Since reactions in solids undercool easily, such determinations will always give too low a temperature for the solvus. 3) Some property of an alloy is measured as a function of temperature while the alloy is above the solvus.5,9,11 The range of temperature can usually be extended slightly into the two phase region. Then the alloy is precipitated at a much lower temperature and slowly reheated. The solvus is taken to be the lowest temperature where the property of the reheated alloy is equal to that previously determined for the homogeneous alloy. Usually one also expects a discontinuity at the solvus in the temperature variation of the property for the reheated alloy. The difficulty in this method is the sluggishness of the dissolution process, and this method may give too high a solvus temperature. EXPERIMENTAL The phase boundary or solvus temperature was determined by a modification of method 3 for a series of chemically analyzed high-purity alloys, ranging from 5.1 to 26.4 at. pct Sn. The resistance, as a function of temperature, of a sample of homogenized alloy (which could easily be undercooled) was compared with the equilibrium resistance which that alloy sample attained after precipitation at room temperature followed by long isothermal anneals at various temperatures. Before each anneal the sample was rehomogenized and reprecipitated. The solvus temperature could be located to within 1°C as the intersection of the resistance vs temperature curves for the homogenized and equilibrium alloys. No attempt was made to locate the phase boundary more accurately since the limiting factor was the precision with which the alloys could be analyzed. This precision was ±0.1 wt pct Sn and corresponds to an error of 1 deg in temperature. This use of isothermal anneals differs from some of the previous investigations in which method 3 was used with baths of slowly rising temperatures. It was found early in the investigation that solvus temperatures tended to be high if the latter method was used even at extremely slow heating rates. For example a

Jan 1, 1961

By H. A. Fisch, A. J. Opinsky, J. L. Bartos

Fort?-six- two-grain bounduries were studied in doped tungsten 1amp wire that had been heated to 3450°K very vapidly. Back-reflection Laue photograms were taken of the grain boundary partners and solved, using a computer. The resulting distribution of large-grain orientations was analyzed. Rotational axes were calculatedfor each grain boundary pair. The axes of least rotation show an anisotropy of rolalional angle. WhILE the orientations of large grains in straight doped tungsten wire have been studied extensively, little has been done to characterize the boundary that separates them. Rosi.1 upon seeing the jagged interlocking boundary in doped tungsten wire. inferred that the grains should have a preferred orientation, and proved it. He interprets his data as indicative of a single ideal orientation—(531)— being parallel to the wire axis. Rieck2, 3 and Mannerkoski' have essentially confirmed this finding. Opinsky, Orehotsky, and Siegle argue that the data suggest that (211)—a plane-is parallel to the wire axis instead. This (211 ) contains the (531). and hence would appear to be a more general case.5 Ahlborn and wasserman6 report that their orientation data stretch from (110) through (531) to (311). This path is the locus of {211 Recently. Opinsky has suggested that the data can be interpreted as a series of ideal orientations that can be related by coincidence relationships to the (110) fiber texture. All these investigators have determined the orientations of the large grains by the back-reflection Laue technique, and they have all obtained similar results. Only Rieck5 as methodically looked at the large grains along a wire. He was apparently not concerned with the relationships of the large grains across their common boundary, but only with their individual orientations. This research was undertaken to fill this gap in the under standing of the mechanical properties of tungsten wire. Only the crystallographic aspects of the problem will be reported here. In addition, the large number of large-grain orientations, which was accumulated in this study. will also be analyzed. EXPERIMENTAL MATERIAL AND TECHNIQUES All of the data were obtained from four pieces of the same 7-mil-diam General Electric tungsten lamp wire. Twelve-inch lengths of the cleaned wire were heated in vacuum by the flick of a switch to 90 pct of the amperes necessary for fusion (a temperature of approximately 3450°K) and held for 1 min. On the basis of other data. it is estimated that the rise time is of the order of 0.5 sec. The four pieces of wire could have come from anywhere within about 18 ft of wire. Consecutive segments of each piece of wire were mounted in bakelite and polished metallographically The polishing procedure followed that described by woods. "nly boundaries between two grains that each occupied the entire cross section of the wire were photographed and X-rayed. The metallographic sample was mounted accurately with respect to the X-ray unit. Steps were taken to read the films as accurately as possible with the conventional Greninger net. The data were then entered into computer programs that solve the Laue film by precisely the same techniques that are used in the solution of the film by means of the stereographic projection. The use of the computer has probably shifted the main source of error from the stereographic plot to the reading of the film. On the basis of several experiments, it is thought that the error associated with the entire process, from mounting the sample through the computer solution, is of the order of about one-half degree. The output of the computer is the direction cosines of the fiducial direction (the wire axis) and the locations of the three cube axes. The former data were used to calculate the differences in orientation between the two grain boundary partners, and the latter were used in the calculation of the rotational axes that could bring the two grains

Jan 1, 1970