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By O. W. Bilharz

INTRODUCTION ACID mine-water drainage is a serious problem with many mines in the Tri-State zinc and lead mining district. Particularly is this true when large volumes must be considered in unwatering old mines that have refilled with water which has dissolved the products of oxidation and has become chalybeate in character. The experiences discussed in this paper have to do specifically with the unwatering of a comparatively small area west of the town of Baxter Springs, Kans., where the pumping job was complicated by water of this type and where the extremely high sulphate content particularly effected that phase of mine drainage having to do with stream pollution. LOCATION, GEOLOGY AND HISTORY The Baxter Springs area of the Tri-State mining field is situated just west of the town of Baxter Springs and is a northeasterly extension of the main mineralized zones of the Oklahoma part of the district (Fig I). The mining area is traversed with well defined shear zones which provide easy circulation of ground waters and the ore bodies are found along these shear zones as localized enrichments wherever the structural conditions are favorable (Fig 2). The ore-bearing strata is Mississippian with an overlain capping of shale of Pennsylvanian age. This shale strata carries much pyrite and marcasite at its base and undoubtedly was a contributing factor to the subsequent high iron content of the water. The area originally contained a sulphide water which discharged as an artesian flow in springs within the town and gave Baxter Springs its name. These springs were famed for many years for their mineral water. This original sulphide water was first removed about 1917 and active mining was carried on west of the town during subsequent high metal price periods. Many small mines were opened, with each localized enrichment becoming a separate mine. During the depression mining ceased and all mines in the west Baxter area were allowed to flood. No serious effort was made to again unwater until higher prices caused from the demand for metal for World War II once more focused attention on this part of the field. ORIGINAL MINING RESULTS IN OXIDATION As plans for unwatering progressed, it soon developed that the mine-water pools had become strongly acid in character and carried large amounts of sulphates in solution. This occurred in the following way. When the original sulphide water was removed, shafts sunk, and mining carried on over a number of years, ferrous sulphate was formed by the spontaneous oxidation of the pyrite beds in contact with air admitted through churn-drill holes and mine openings. These products of oxidation can be seen today in the old mines of the district as crusts of crystalline sulphates

Jan 1, 1947

By M. R. J. Wyllie, H. W. Patnode

In the quantitative interpretation of electric log data it is essential to know the formation factor, defined as the ratio of the resistivity of the formation 100 per cent saturated with brine to the resistivity of the brine.' This concept implies that the formation factor for any given rock is constant irrespective of the resistivity of the brine or solution with which it is saturated. It is apparent that this can be true only when the rock matrix is wholly non-conductive. As reservoir rocks may contain clay or shale having an appreciable conductance one may expect these constituents to influence the determination of true formation factor. The formation factor may be theoretically derived from log data by dividing the resistivity of the mud filtrate invaded formation by the resistivity of the mud filtrate. Such a method of calculntion has implicit in it the assumption that the fluids in the invaded formation are wholly replaced by mud filtrate. that the solid matrix is non-conducting, and that the formation factor of the invaded zone is identical with the formation factor of the uninvaded zone. Since the validity of the first two basic assumptions regarding the insulating character of porous matrices and the displacement of the interstitial fluids in porous media do not appear to be fully established, the formation factors of a number of cores and clay slurries have been measured under conditions suitable for verifying the assumptions and the extent of any errors inherent in them. CORE STUDIES Apparatus and Procedure Resistivity measurements were made on short cylindrical permeable cores which had been previously mounted in lucite.2 The cores were clamped by means of insulated bolts between brass plates about 5 cm square and 1 cm in thickness. The plates were provided with a ring seal to prevent leakage between them and the core mount, and had a centrally located orifice so that fluids could be flowed through the mounted core. The brass mounting plates were used as electrodes and any current flow between them necessarily passed only through the constituents of the intervening core. Fluid saturation of the core, and fluid flow through the core, were effected by a centrifugal pump connected to the outflow end of the core, thus providing a differential pressure across the core of approximately one atmosphere. The procedure used was first to evacuate each core by means of the pump and then to saturate the core with an aqueous sodium chloride solution of known resistivity. The resistance of the core was measured and flow of the solution through the core continued for sufficient time to establish a constant resistance reading. After equilibrium had been reached with one solution, another sodium chloride solution of a different resistivity was flowed through the core and the flow continued until a constant resistance reading was again obtained. This procedure was continued until resistance measurements of the core had been made with a series of solutions within a salinity range from 1.0N NaCl to distilled water. The data obtained enabled the apparent formation factor of given porous rocks when saturated with fluids of different resistivity to be computed and also provided information regarding the ability of an invading fluid to displace interstitial water from a core. Results Berea Sandstone — The first core examined was a specimen of Berea sandstone." This core had been cut essentially parallel to the bedding for permeability studies. The core was clamped in the core holder and saturated with 1.0N NaCl solution and the resistance determined. It was subsequently flushed and the resistance measured when saturated in turn with 0.1N, 0.025N, 0.01N, .005N sodium chloride solutions and finally with distilled water. In flushing the core with each

Jan 1, 1950

By John R. Freeman

The die pressing of brass may be described as a method of producing irregularly shaped parts of brass and other copper alloys by hot deformation in a die under pressure. Die pressing of brass was first developed as an improvement on sand castings in order to obtain irregularly shaped articles of brass with superior surfaces, a closer tolerance in dimensions, a denser structure, freedom from porosity and elimination of the relatively large amount of scrap invariably attached to sand castings. The freedom from sandy surfaces with consequent greater tool life in machining operations was also recognized as well as elimination of losses due to the uncovering of blowholes in machining operations. Die pressing also gave alloys of superior strength. Die pressings today are made from extruded rod or shapes, according to design of the part to be made. The greater number of pressings are made from round rod, because of its relatively lower cost and ease of handling. The rod is first sheared or sawed into desired lengths, the diameter of rod used and length of "slug" or "rivet" depending upon ultimate weight and shape of the die-pressed part to be made and design of die. The dimensions of the slug are figured so as to give the minimum amount of scrap to be sheared from the pressing as it comes from the die. Extruded shapes having I, T or X sections are often used when the finished part is to have a similar shape or heavy sections are joined by relatively light sections of considerable length. A rod bent in the shape of a U is also used on occasion, for similar reasons. Proper shearing of the slugs is of considerable importance. The sheared ends of the slugs should be as flat and straight as possible. Improperly sheared ends having an angle to the axis of the bar or a rough, uneven surface are liable to give folds or laps in the finished pressing and proportionately high rejections. The property of shearing varies considerably with different alloys and should be considered in the selection of a material for a given part. Where satisfactory shearing is not possible, the slugs may be cut from the bar by power saws. Extruded

Jan 1, 1931

By A. Eilers

A number of the copper refineries in this country have lately separated some of the rarer metals from the slimes in the refinery tanks. One of these has furnished me the following table of recoveries from given amounts of blister. I publish this to show the proportions, to gold and silver and to each other, in which these rarer metals may be expected to occur in copper from certain localities. GarFIeld, Utah :—The blister copper comes principally from the Bingham porphyry copper mines. Steptoe, Nev. :—All the blister copper is produced from the Nevada Consolidated mines. (Also porphyry deposits.) Omaha, Neb. :—Blister copper comes principally from concentrated copper-lead mattes shipped from the different lead-silver plants of the Rocky Mountain region to the converters at the Omaha lead refinery. Mountain, Cal. :—Ores occur in connection with diorite (?).

Jan 1, 1914

By S. H. Penn

Preliminary experimental evidence seems to preclude the use of unlubricated mechanical force drills on the moon. Measured values of the coefficients of friction and adhesion between metallic and nonmetal-lic solids have been shown to increase in an ultra-high vacuum environment. The paucity of real knowledge of the influence of a hard lunar vacuum upon interacting solid surfaces, relegates current proposals to sample the moon with a mechanical force drill, to the equivalent of wildcatting on earth. Within a few years, drilling will be attempted on the lunar surface with tools that have been designed with parameters that are normally considered for most conventional terrestrial drills. Lunar drills must be light in weight, portable, have reasonable penetration rates, low manpower requirements, etc. Although the initial equipment cost is expected to be high, this will probably not be a critical factor. Early lunar drilling will be limited to shallow holes with depths of 10 ft or less. The primary function of these holes will be to furnish samples of lunar surface materials but they may also be utilized for other purposes, such as geophysical experiments. Instruments may be installed in them capable of measuring thermal diffusivity, gamma radiation, etc. As sampling will be the primary objective of the earliest holes, sample contamination is a parameter that effectively excludes such otherwise promising techniques as explosive or plasma jet drilling. The most desirable method is probably some form of mechanical force drilling that has the capability of operating in the extreme lunar thermal environment (125° to 37S°K), high vacuum (10- l3 torr range), and low gravity.

Jan 1, 1968

By Ernest L. Ohle

IN 1943 diamond drilling from the surface in an area 2 miles southwest of Leadwood, Mo., discovered a lead deposit of a markedly different character from the usual southeast Missouri type. Subsequent drilling of about 500 holes indicated several million tons of ore, and in 1950 a 701-ft vertical shaft was sunk into the orebody. This paper describes the geology, of this interesting occurrence insofar as it is known from the drilling and the small underground exposure at the bottom of the shaft. Geology The location of the Southeast. Missouri Lead Belt and of 'the Hayden Creek property are shown in Fig. 1. As shown here, there are two separate producing areas, one from which the larger tonnage has come, located near Bonne Terre, Flat River, Desloge, and Leadwood, and the other to the south around Fredericktown and including famous old Mine LaMotte. The best published description of Lead Belt geology is by Tarr.* In pre-Cambrian time in this cherty dolomites. Several of these formations may be found in direct contact with the pre-Cambrian as their deposition progressively overlapped the older rocks on the flanks of the igneous knobs and ridges. Immediately overlying the pre-Cambrian there is, not uncommonly, a thin basal conglomerate of granite or porphyry boulders, which is incorporated into the overlying sediments. Deposition of the lower part of the rock section was fairly continuous, and the Lamotte sometimes grades almost imperceptibly into the lower sandy Bonneterre. Since the sediments were deposited on an uneven floor, they tend to reflect the irregularities in that floor. Most of the steep dips found in the district, that is, dips in excess of 10°, are original dips and not caused by deformation. Such domelike structures in the sedimentary rocks around the igneous knobs have localized a considerable number of the orebodies in the district and particularly those in the Fredericktown area. Many of the larger orebodies, however, have no close relation to the pre-Cambrian topography. Most of the lead production has come from the lower 150 ft of the Bonneterre formation, where disseminated ore spreads laterally parallel to the bedding for great distances. Average stoping height is about 20 ft, but in a few places there are stopes over-175 ft high.

Jan 1, 1952

By W. T. Thom

Many able men have contributed to the subject of coal classification, and recent publications on the subject have indicated a crystallization of opinion in that connection which promises the development in the near future of a scheme of coal classification which will be of real and increasing value to coal producers and users, as well as to those interested in coal on more exclusively scientific grounds. It is obvious that such a classification must be simple; must be based upon readily ascertainable factors; and if properly developed will apply to the whole range of coals between peat and anthracite and not merely to certain types of coal. Many of the numerous schemes of classification proposed in the past have given quite satisfactory results when applied to the higher rank coals, but have broken down when applied to the younger coals of higher moisture, and, as previously pointed out by the writer,' this breakdown has been due to the practice of ruling out "moisture" as an essential component of the volatile matter reported in the customary proximate analysis of coal, whereas a review of the mode of formation and natural history of coal satisfies us that moisture is a normal and natural ingredient among its volatile constituents; and a knowledge of analytical practice shows that the "moisture" and "volatile matter" reported are both mixtures of moisture and volatile matter, rather than sharply differentiated distillation fractions. After an extended consideration of the subject the writer regards the conventional proximate analyses of coals as affording the information essential for a both practically and scientifically satisfactory c1assification—assuming that the coal samples compared have been collected and analyzed according to standard methods. Two variables are required for a workable classification, and these appear to be afforded by the calorific value and proportion of volatile constituents (including moisture) credited to the coal on an ash-free basis. The writer originally proposed that the figures used for classification purposes be those given for the "air-dried" and "ash-free" form of the proximate analysis,

Jan 1, 1930

By C. B. Auel

THE subject of this paper involves the crux of the industrial safety problem. It is not overstating the fact to say that "a plant can be made as safe as the management and the workers want it to be;" if such desire is not in evidence and it is not possible to maintain interest in the work of safety, there can be practically no headway beyond the first few steps. These first steps may be said to embrace simply the mechanical or equivalent guarding of tools and equipment and may be taken in a more or less perfunctory manner; but, it has been estimated, they will not effect a reduction of more than 25 to 35 per cent. in the accidents likely to occur in an unguarded plant. The question therefore may be pertinently asked, "Whose interest is meant in the title of this paper, employers', employees?, or both?" It has been repeatedly stated that no safety work of any importance can be carried on: in a plant unless the employer believes in the value of such work. Such statements are true, but have become threadbare with constant repetition and the public is led to believe, that employers differ from ordinary human beings, that their sympathy for their fellowmen has become dulled, and they can be awakened to a sense of the fitness of things with respect to safety, health, sanitation, working hours, etc. only by legislation. There will undoubtedly be found an employer, now and again, who measures down to such specification; but the speaker, in a number of years of close contact with large employers (and his experience has been duplicated by many others) has found that the employers are usually far in advance of the general public in matters affecting the welfare of their employees, including their safety, and not from a selfish viewpoint, but from the humanitarian, economic, etc. If, at times, there is an apparent lack of headway in the solution of some problem connected with employees' welfare, it is not so much due to indifference or a failure to be awake, on the part of the employer, as it is to a lack of knowledge of the way in which to proceed to its successful accomplishment. Further, employers are, only human and cannot follow. every one of the innumerable matters connected with an industry down to their minutest details; they must delegate certain individuals as their representatives, clothing them with the necessary authority to act. These representatives should be looked upon as the Management in their respective fields and the

Jan 6, 1925

By P. D. S. St. Pierre

IN recent years the use of high sulphur fuels and charges in steelmaking has necessitated rapid methods of slag control in order to insure the production of high quality steel. Several systems of control have been discussed in the literature, and of these the method described by Philbrook, Jolly, and Henry' has received the most attention recently. In their process the hydrogen ion concentration of an aqueous slag suspension is determined under controlled, but arbitrary conditions. The basicity of the slag may then be derived from a previously established pH-V ratio curve. Thus, by measuring the pH, some indication of the V ratio is gained, from which significant properties of the slag may be deduced. Philbrook et al. made no claims as to the theoretical justification of their treatment, but simply offered it as a rapid means of slag control. Encouraging results caused others to study the method and publish their findings.2-5 Although there was fair agreement on the efficacy of the method, no common parameter was evolved against which pH readings could be plotted. The results of the various determinations were related to such V ratios as CaO/SiO2 and CaO/ SiO2 + P2O5 by some,'-3 while others" plotted against "excess lime." Rivet,' however, found a simple proportionality between the hydrogen ion concentration and the sulphur content of the molten steel beneath the slag. Since slag control in North American practice is largely directed toward the efficient removal of sulphur from steel, Rivet's approach to the problem had the advantage of connecting directly a property of the slag with the impurity being removed. In view of the diversity of parameters used it seemed probable that some fundamental point was being overlooked in seeking a relationship. Examination of the literature revealed that much emphasis had been laid on experimental detail but scant attention paid to the fundamental aspects of the hydrolysis of the aqueous slag suspension. Consequently the present investigation was undertaken with the object of rectifying this deficiency and deriving, if possible, a parameter of general application. Petrographic studies on several matured Canadian open-hearth steel slags have shown that their major constituents are dicalcium and tricalcium silicates set in a complex matrix of iron oxides and ferrites. These phases are shown in Figs. 1 and 2. Free lime is frequently encountered in slags, but is not an equilibrium phase since on continued heating it dissolves forming silicates or ferrites. Thus, it appeared that a study of the hydrolysis of the major phases in steel slags would be profitable. The experimental technique used in the present work was a modification of that described by the other workers.'- Electrical conductivity measurements were also made on the suspensions, since Smith et al." had claimed advantages for this method in their paper on slag control. Experimental Procedure The compounds studied in this investigation were prepared in the laboratory by heating purified oxides

Jan 1, 1954

By Clare B. Carlson, C. P. Proctor

THE history of the froth flotation of coal is relatively short. The flotation process was applied to fine-coal cleaning about the time of the end of World War I. Coal flotation finds more widespread use in Europe than in the United States and is used on a commercial scale in nearly all major coal-producing countries in the world. In Fig. 1 the general arrangement of a froth-flotation plant at a British colliery is shown. GENERAL FEATIJIEES OF THE PROCESS Application The flotation process is applicable to the cleaning of the fine sizes, particularly minus 48-mesh coal, although it may be used on sizes as coarse as 1/8 in. Since most cleaning processes usually are not effective on sizes smaller than 48-mesh and certainly not effective on minus 100- mesh, the froth-flotation process offers a solution to the problem of cleaning these sizes. This process consists-of agitating the feed pulp with a small amount of reagents, usually 1.0 to 2 ½ lb. per ton of feed in the presence of water and air; the reagents help to form small bubbles that collect on the particles having a greater affinity for the bubble surface than for the water surface, in this case the fine coal, and the bubbles buoy these particles to the surface to form the frothor concentrate. Slate and shale particles remain wetted and suspended in the water to be drawn off as tailing. The frothers commonly used in coal flotation are cresylic acid, pine oil, and alcohols. More expensive frothers, used in ore flotation, work satisfactorily but do not compare with these cheaper reagents for over-all cost. Collectors- used are low-grade petroleum fractions, such as cheap, partly refined fuel oil, or lubricating oil, sometimes mixed with small amounts of kerosene. Other collectors used are the fatty acids and their

Jan 1, 1943

By Gerhard Derge

Metallurgists have used borax as a fluxing agent traditionally, but until recently elemental boron has played an insignificant role as an alloying element. Neither the metal nor its compounds have been regarded as important metallurgical materials and there is a surprising lack of knowledge concerning their metallurgical behavior. The new applications to steel-making of both boron and borates, which arose in part from wartime incentives and restrictions, have been seriously handicapped by this lack of data. For example, rasorite, a naturally occurring sodium borate, has been shown to be an effective substitute for aluminum as a ladle deoxi-dizer in rimming steels.' Likewise, the effectiveness of boron as an alloying agent has been demonstrated,2,3 giving deep hardening when used in restricted amounts. The exploitation of both of these uses has been retarded by the difficulty of attaining suitable metallurgical control. Recognizing that the most important information required was a knowledge of the equilibrium between boron and oxygen dissolved in liquid iron. Gurry4 calculated this relation from the best thermal data available. However, estimates of the entropy of melting of boron, the activity coefficient of boron in liquid iron and the activity coefficient of B2O3 in slag were involved, and experimental work on this problem was obviously desirable. The experiments to be described were planned to establish the boron-oxygen relations in liquid iron and to demonstrate at the same time the ferroborate slag compositions in equilibrium with various amounts of oxygen in liquid iron. Accordingly, slags containing varying proportions of iron and boron oxides were held in contact with molten iron, and samples of both slag and metal were analyzed. The limitations upon the accuracy of the data will be considered, but in a practical sense the oxygen levels that can be attained in iron by iron borate slags, and the amounts of boron in iron at these oxygen levels were established. Experimental Procedure No entirely suitable refractory was found for the mixtures of iron oxide and boron oxide used as slags. Crucibles of silica, magnesia, Ramix, beryllia, and zirconia were all tried unsuccessfully. The must satisfactory method discovered for handling them was the rotating-crucible technique, which creates a parabolic crucible of liquid iron.5,6 Even this was not entirely successful, for at steelmaking temperatures (1600°C.) the slags had such a low surface tension that they crept up to the refractory and slowly dissolved it. These difficulties made it impossible to maintain a constant slag composition for an unlimited period Of time. However, by using the rotating technique, short runs could be made in

Jan 1, 1947

By Gerhard Derge

Metallurgists have used borax as a fluxing agent traditionally, but until recently elemental boron has played an insignificant role as an alloying element. Neither the metal nor its compounds have been regarded as important metallurgical materials and there is a surprising lack of knowledge concerning their metallurgical behavior. The new applications to steel-making of both boron and borates, which arose in part from wartime incentives and restrictions, have been seriously handicapped by this lack of data. For example, rasorite, a naturally occurring sodium borate, has been shown to be an effective substitute for aluminum as a ladle deoxi-dizer in rimming steels.' Likewise, the effectiveness of boron as an alloying agent has been demonstrated,2,3 giving deep hardening when used in restricted amounts. The exploitation of both of these uses has been retarded by the difficulty of attaining suitable metallurgical control. Recognizing that the most important information required was a knowledge of the equilibrium between boron and oxygen dissolved in liquid iron. Gurry4 calculated this relation from the best thermal data available. However, estimates of the entropy of melting of boron, the activity coefficient of boron in liquid iron and the activity coefficient of B2O3 in slag were involved, and experimental work on this problem was obviously desirable. The experiments to be described were planned to establish the boron-oxygen relations in liquid iron and to demonstrate at the same time the ferroborate slag compositions in equilibrium with various amounts of oxygen in liquid iron. Accordingly, slags containing varying proportions of iron and boron oxides were held in contact with molten iron, and samples of both slag and metal were analyzed. The limitations upon the accuracy of the data will be considered, but in a practical sense the oxygen levels that can be attained in iron by iron borate slags, and the amounts of boron in iron at these oxygen levels were established. Experimental Procedure No entirely suitable refractory was found for the mixtures of iron oxide and boron oxide used as slags. Crucibles of silica, magnesia, Ramix, beryllia, and zirconia were all tried unsuccessfully. The must satisfactory method discovered for handling them was the rotating-crucible technique, which creates a parabolic crucible of liquid iron.5,6 Even this was not entirely successful, for at steelmaking temperatures (1600°C.) the slags had such a low surface tension that they crept up to the refractory and slowly dissolved it. These difficulties made it impossible to maintain a constant slag composition for an unlimited period Of time. However, by using the rotating technique, short runs could be made in

Jan 1, 1947

By B. C. Wonsiewicz, W. W. Wilkening

Following a procedure proposed by Wheeler and Ireland, Plane stress yield loci were constructed from Knoob hardness numbers. Basically, six differently oriented hardness measurements were made on three orthogml surfaces through pure poly crystalline magnesium sheet, a magnesium single crystal, and sheet of the magnesium alloys: Mg + 0.5 pct Th, Mg + 4 pct Li, AZ31B, and EKOO. Hardness loci were found to be in poor agreement at small strains (E < 0.05) with loci established by a more rigorous technique. At larger strains (E - 0.10) the agreement is fair, but at this stage in deformation the conventional locus has lost much of the asymmetry that characterizes these anisotropic materials. Two effects which will lead to distortions in the Khn locus are discussed with reference to the geometry of plastic flow during a hardness test. DETERMINING a material&apos;s resistance to multiaxial loading is of interest not only from a structural design viewpoint but also from that of deformation processing. Unfortunately, the determination of the yield locus, although simple in principle, involves tedious procedures if the results are to be at all rigorous.&apos; The idea, first proposed by Wheeler and 1reland2 of determining the yield locus by means of six Knoop hardness impressions along the principal directions in a material has obvious appeal. It is simple, quick, and should be applicable to very thin sheets. If such a technique could be demonstrated to produce consistently reliable results, it would be of interest to both researcher and designer. Lee, Jabara, and ackofen have compared the yield locus determined by Knoop hardness measurements (the Khn locus) to a locus determined by more rigorous techniques. They found good agreement for two titanium alloys at a plastic strain of about 1 pct. The purpose of this paper is to investigate if the Khn locus construction is a reasonable approximation to the locus of a highly anisotropic material. Examples of such materials are magnesium and magnesium alloys which have severely distorted yield loci which in turn reflect markedly dfferent yield strength in different directions.&apos; In pure magnesium, for example, the yield stress in tension along the transverse direction may be four times the yield stress in compression in the same direction and twice the tensile yield stress in the rolling direction. Predicting such large differences ought to serve as a severe test of the Khn locus construction. EXPERIMENTAL PROCEDURES Samples of rolled sheet, 0.250 in. (6.35 mm) thick, of pure magnesium and four magnesium alloys (Mg experimental materials. The pure magnesium together with the lithium and thorium alloys were those used in the study of Kelley and Hosford. The grain size was ASTM number 4 for the pure magnesium and number 6 for the alloys. HARDNESS TESTING The materials were sectioned along the rolling and transverse planes, mounted in a quick setting resin, and mechanically polished. Most of the hardness tests were performed on a surface prepared by electro-polishing (30 pct nitric acid in methanol at 0°C and 20 v) with the exception of the AZ31B and EK00 alloys which were made directly on a metallographically polished surface. However, subsequent hardness tests on the same sample after heavily electropolishing, revealed essentially the same hardness as before. At least twenty Knoop hardness impressions under a 100-g load were made in each of the six orientations shown in Fig. 1. The average hardness number and standard deviation were then calculated for each orientation. CONVENTIONAL LOCUS CONSTRUCTION Yield loci were constructed using a technique described in detail by Lee and ackofen,&apos; in which the flow stress (stress at a given plastic strain) fixes the coordinates of a point on the locus and measurements of the strain ratio serve to establish the slope of the locus at that point. The loading paths which correspond to uniaxial tension or compression tests establish the four intercepts of the locus with the coordinate axes plus one point on the balanced biaxial tension line Tensile testing was performed along the rolling and transverse (r, t) directions. Samples had a uniform rectangular gage length 1 by 4 by 4 in. (25.4 by 6.35 by 6.35 mm) and were deformed at a strain rate of 3.33 x 104 sec-&apos;. The tests were interrupted periodically to unload the sample and measure the plastic strains by means of X-Y post yield strain gages. Compression tests in the rolling, transverse, and through-thickness (r, f, z) directions were performed on 1/4 in. (6.35 mm) cubes at an initial strain rate of 8.33 x sec-&apos;. Lubrication was provided by 0.002 in. (51 pm) Teflon sheet which was renewed after unloading for micrometer measurements used to calculate the strains.

Jan 1, 1970

By A. D. Mutch

IT has long been known that there are wide variations in the thermo-electric potential of pyrite. In the last few years a study of this variation and other properties of pyrite was carried out at the University of Toronto by F. G. Smith on specimens of pyrite from many localities.1-3 As a result of these studies the pyrite geothermometer was developed by Professor Smith. The calibration of the pyrite geothermometer is based on the assumption that "crystals of any one electronically conducting mineral species deposited at a high temperature have a more positive thermo-electric potential than crystals deposited at a low temperature, and the thermo-electric potential varies continuously between any given limits of the temperature of deposition." The cause of the variation was postulated to be crystal discontinuities, such as lineage boundaries. As yet this postulated relationship has not been established as fact. On theoretical grounds it is indicated that the thermo-electric potential of pyrite or any other partial conductor is dependent upon a number of factors as well as the temperature of formation. For this and other reasons there is ground for doubt as to the validity of the relationship postulated above. To date a large number of readings have been made with the pyrite geothermometer which have been recorded in terms of the calibration of the instrument in degrees centigrade. So far most of the pyrite tested by this technique has been in association with gold ore. The values for the temperature of formation obtained in these tests appear to be reasonable and, in relation to geological problems, to vary in the right sense. Determinations on some specimens not in association with gold ore have given readings that appear to be much too high, taking into account the probable maximum temperature of the host rock. To sum up, although many determinations made with the. pyrite geothermometer appear to give reasonable values for the temperature of formation of the pyrite, there are at the same time other readings which seem anomalous. On the basis of an examination of available results of work with the pyrite geothermometer, two problems must be considered: 1-the validity of the calibration of the pyrite geothermometer; and 2-the nature of the distribution of the thermo-electric potentials of pyrite in relation to the specific problems that have been examined. In this paper the academic problem relating to the validity of the calibration of the pyrite geothermometer will not be discussed. Instead, the variations of thermo-electric potential of pyrite in association with gold veins will be discussed with regard to specific examinations. The first of these two examinations deals with the distribution of thermo-electric potentials of pyrite in association with a gold vein and was carried out in the McIntyre Porcupine Mine, Schumacher, Ont., in the summer of 1949 as part of a study with this technique. The second problem deals with variations of thermo-electric potential of pyrite in gold ore specimens from all over the world. The specimens used in this study were part of the private collection of Frank Ebbutt, geologist for Howe Sound Exploration Co. Results of Detailed and Reconnaissance Studies In discussion of the results of determinations made in these two studies the values of thermo-electric potential in millivolts will be used. It will be noted that in some of the diagrams the determinations are recorded in terms of pyrite geothermometer temperatures. Fig. 1 is a calibration chart relating, pyrite geothermometer temperatures and thermo-electric potentials. A full discussion of the technique is given in the original paper by F. G. Smith.&apos; Briefly, the determinations are made by placing two stainless steel probes, one hot and the other cold, against the surface of the pyrite crystal being tested. The thermo-electric potential that is developed is read with a null-point potentiometer that is calibrated in what

Jan 1, 1952

By Gerhard Derge

METALLURGISTS have used borax as a fluxing agent traditionally, but until recently elemental boron has played an insignificant role as an alloying element. Neither the metal nor its compounds have been regarded as important metallurgical materials and there is a surprising lack of knowledge concerning their metallurgical behavior. The new applications to steelmaking of both boron and borates, which arose in part from wartime incentives and restrictions, have been seriously handicapped by this lack of data. For example, rasorite, a naturally occurring sodium borate, has been shown to be an effective substitute for aluminum as a ladle deoxidizer in rimming steels.1 Likewise, the effectiveness of boron as an alloying agent has been demonstrated, 2,3 giving deep hardening when used in restricted amounts. The exploitation of both of these uses has been retarded by the difficulty of attaining suitable metallurgical control. Recognizing that the most important information required was a knowledge of the equilibrium between boron and oxygen dissolved in liquid iron, Gurry4 calculated this relation from the best thermal data available. However, estimates of the entropy of melting of boron, the activity coefficient of boron in liquid iron and the activity coefficient of B203 in slag were involved, and experimental work on this problem was obviously desirable. The experiments to be described were planned to establish the boron-oxygen relations in liquid iron and to demonstrate at the same time the ferroborate slag compositions in equilibrium with various amounts of oxygen in liquid iron. Accordingly, slags containing varying proportions of iron and boron oxides were held in contact with molten iron, and samples of both slag and metal were analyzed. The limitations upon the accuracy of the data will be considered, but in a practical sense the oxygen levels that can be attained in iron by iron borate slags, and the amounts of boron in iron at these oxygen levels were established. EXPERIMENTAL PROCEDURE No entirely suitable refractory was found for the mixtures of iron oxide and boron oxide used as slags. Crucibles of silica, magnesia, Ramix, beryllia, and zirconia were all tried unsuccessfully. The most satisfactory method discovered for handling them was the rotating-crucible technique, which creates a parabolic crucible of liquid iron 5,6 Even this was not entirely successful, for at steelmaking temperatures (1600°C.) the slags had such a low surface tension that they crept up to the refractory and slowly dissolved it. These difficulties made it impossible to maintain a constant slag composition for an unlimited period of time. However, by using the rotating

Jan 1, 1946

By Robert Pring

IN addition to the humanitarian aspects of a dust-control program, certain economic benefits are becoming more fully recognized and now furnish a greater incentive to the mill operator to eliminate the dust from his plant. It is well known that a favorable working environment promotes increased efficiency and improves the morale of em-ployees, with a consequent decrease in labor turnover rates. One progressive mining company estimates its direct and indirect labor turnover costs at from $40 to $50 per man; for skilled labor, such as machine operators, the cost may approach $100 per man. While these figures may not be typical of every plant, they do indicate a potential savings in operating costs. Dust signifies waste; its elimination de-creases maintenance costs of mechanical and electrical equipment; its recovery is often justified from the standpoint of values contained in the collected material, although in large-scale milling operations handling low-grade ore this may not be an important factor. Perhaps the most significant trend in industrial sanitation is that dust-control equipment and procedures are becoming recognized as integral parts of the mill flow-sheet. Exhaust ventilating systems are now afforded equal care in design and mainte-nance to that given other machinery more closely related to the process,

Jan 1, 1940

Arizona E. P. MATHEWSON, Chairman F. W. MACLENNAN, First Vice-chairman CLYDE E. WEED, Second Vice-chairman E.D. GARDNER, : Secretary-Treasurer Box 4097, University Station, Tucson, Ariz. ARTHUR CROWFOOT G.H. DOWELL HENRY F. EASTER R.D. LEISK Boston Meets first Monday each month, October to May, inclusive GEORGE, W. METCALFE, Chairman ROBERT S. WILLIAMS, Vice-chairman F. LEROY FOSTER, Secretary-Treasurer Rooms G-202, Mass. Inst. of Tech. Cambridge, Mass. FREDERICK K. MORRIS GEORGE A. PACKARD

Jan 1, 1934

By W. R. Opie

The object of this paper is to show the manner in which typical electrodeposits of hexagonal-close-packed metals—zinc, titanium, and zirconium—tend to form. The conditions of electrodeposi-tion markedly affect the nature of the deposits in regard to crystal size, orientation, and appearance. No attempt is made to correlate cell conditions with deposit quality but, rather, characteristic types of deposits were selected and a study made to show the relationship between outward appearance and crystal structure. The zinc deposits were made in aqueous electrolytes and the titanium and zirconium deposited from fused salt baths. ZINC deposits studied were made in the American Smelting and Refining Co.&apos;s Central Research Laboratories. They were representative of bright, shiny, smooth deposits, which can be obtained by using proper current densities and electrolyte addition agents, and of deposits which are dull and tend to be nodular. Four deposits were selected which ranged from smooth and bright to very nodular and dull, and their classifications are shown in Table I. These were examined microscopically and were found to differ quite markedly in outward surface structure and in microstructure. The outward surface variation is illustrated in Figs. 1 to 4. At X50 the texture could be seen to progress from granular to platelike to smooth. The microstructures of the deposits&apos; cross sections from starting sheet to outer surface are shown in Figs. 5 through 8. The dull nodular deposits (sample Nos. 1 and 2) show some tendency for acicular growth. The platelike sample (No. 3) shows tendency for columnar growth development and the smooth deposit (No. 4) has a well developed columnar structure. Back-reflection X-ray patterns of the deposit surfaces revealed some interesting information. The crystal orientation was random in all deposits except the smooth deposit. Fig. 9 is a typical back-reflection pattern of a nodular deposit. All planes are reflecting in the proper relative intensity. The pattern of the smooth deposit is shown in Fig. 10. The only planes which reflect are the (10.4). This series of planes is in the right position, with the FeKa radiation used, to satisfy the Bragg equation if the basal planes {00.1) are at right angles to the X-ray beam. The results were interpreted to mean that in the bright smooth deposit preferred orientation has occurred with the basal hexagonal planes oriented in the plane of the sheet but with all other planes randomly oriented around the c-axis.

Jan 1, 1957

By John E. Conley

THE production of lime by the burning or calcination of limestone, including all varieties from true dolomites and magnesian limestones to high-calcium types, continues as one of the essential basic industries. In 1937, a total of 4,124,165 tons of lime valued at approximately $30,091,000 was produced in the United States.1 The importance of any contribution to our knowledge on the mechanism of the lime-burning process is, therefore, obvious. The burning of limestone has been practiced since the earliest days of our civilization, and the literature on the various phases of the industry is voluminous. Calcination of the various types of limestone has been studied by many previous investigators, but some points require additional research. Each occurrence of limestone provides an opportunity for specific investigation, because the characteristics of stones in different localities vary Knibbs13 has given an excellent discussion of available data on the theory of lime and magnesia burning. The thermal dissociation of calcium carbonate has been studied more recently by Johnston,2 Smyth and Adams,3 Ralston et al.,4 Furnas,5 Potapenko,6 and Southard and Royster.7 As a result of these investigations the dissociation temperature at atmospheric pressure has been established as 894º to 898º C. The dissociation of dolomite and magnesite, although studied by several investigator,4, 6, 8 still requires clarification by additional data. The calcination of limestone was studied for a twofold purpose: (1) to extend our information on the mechanism of the lime-burning process and (2) to standardize the conditions for calcination of high-calcium and dolomitic limestones for subsequent hydration tests on the lime.

Jan 1, 1939

By J. H. Brophy, A. I. Prill

The authors have previously investigated the solid-state activated sintering of tungsten powder with various Ni-Cu additions.&apos; Log shrinkage vs log time plots showed changes in slope from 4 to x at intermediate times during the sintering process. This was attributed to a change in the rate-controlling mass-transport process from solution of tungsten into the tungsten-alloy interface to diffusion of tungsten in this interface. It was postulated that the melting of the activating layer should not affect this transport process. However, the superposition of rearrangement due to the presence of a liquid phase complicates the data analysis. It is the purpose of this note to apply the analysis of Prill, Hayden, and rohy&apos; to account for "rearrangement shrinkage&apos;? in liquid-phase sintering of the W-Ni-Cu system. This results in "solution-precipitation stage" shrinkage plots which were comparable to those obtained in solid-phase activated sintering of the same system. If one assumes total shrinkage to be the sum of rearrangement and solution precipitation, the effects can be isolated easily.2 This results in the general equation:

Jan 1, 1967