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By R. K. Matheson

The Nivloc mine is 9 miles west of Silver Peak, Esmeralda County, Nevada. It has been operated by Desert Silver, Inc., since the summer of 1937. The cyanide mill treats 190 tons of silver-gold ore per day. In March of this year the main operations were about 2000 ft. west of the main shaft, which served as the downcast air passage for the mine. The mechanical blowers in use were sufficient to ventilate the west end at that time, but it was foreseen that as the mining area was extended ventilation would be an increasingly difficult problem, especially during the summer months. It was decided, therefore, to continue a raise from a point 100 ft. above the highest mining level (440-ft. level) to the surface; a distance of 443 ft. at approximately 65°. From this point 40 ft. of drifting would be necessary to connect with a shallow shaft on the surface. (Fig. I.) All the raise was serviced from the 440-ft. level; costs and progress obtained in the initial 100 ft. are included in the following pages. Choice of Raise A raise in this locality would have four objects: (I) to provide an ample supply of fresh air to the working places; (2) to explore the vein from the highest mining level to the surface; (3) to provide waste fill for stopes in the area, and possibly provide a transfer for waste from the surface; (4) to provide an emergency exit in the west end of the mine. Before the mining of an ore shoot in the eastern part of the mine, a similar raise had been driven for purposes of ventilation and exploration. This raise and subsequent mining showed the vein to be noncommercial for a distance of about 250 ft. below the surface. However, in the area under operation, old surface workings showed occasional values. Thus from a development standpoint the raise was an excellent prospect. The raise chosen was a three-compartment, stulled raise having two chutes and a manway. The manway inside timber measured 4 ft. 8 in. by 4 ft. 6 in.; it carried air and water pipes, a ladderway and a slide for a timber skip. The two chutes would be used for drawing off the muck and the cleaning of the bulkhead, as well as for ore and waste passes, which would be especially useful for lateral exploration from the raise. The fairly large cross section of the raise (6 by 15 ft.) would provide a large quantity of waste for backfilling, and more could be obtained from a glory hole on the surface. Time Schedule As speed in completing the raise was the main requisite, three shifts were considered, but two shifts were decided upon when it was found that three would necessitate considerably larger fans than those available for clearing the raise. The main diffi-

Jan 1, 1943

By Ernest N. Patty, Sherwin F. Kelly

The present case history deals with the examination of an almost forgotten nickel prospect, near Winesap, Chelan County, Washington. Although the final results yielded no ore body of commercial importance, the integration of surface and underground exploration, geophysical survey and diamond drilling endow the story with interest. The program is significant because it is illustrative of how the most disappointing expenditures in mining exploration, the "not-finding" costs, could have been reduced had geophysical methods been applied at an appropriate stage in the prospecting work. The Chelan nickel deposit was discovered about 1900, on a sage-brush-covered hillside with a southerly slope, adjacent to Winesap Canyon; the paved highway now extending from Wenatchee northward, up the Columbia River and into Okanogan Valley, is only a mile away. After the deposit was found, three short prospect tunnels were driven into it, and the prospect then remained dormant for 40 years. No. x tunnel was 80 ft. long, running north into the hillside. For the first 35 ft. this adit exposed a typical, iron-stained gossan with streaks and stains of malachite, and small seams of water-soluble nickel sulphate. Beyond this, it encountered a relatively fresh peridotite, well mineralized with blebs of pentlandite. Systematic sampling yielded an average assay of 1.5 per cent nickel and 0.3 per cent copper. Down the hillside to the south and 35 ft. lower in elevation, No. 2 tunnel was driven under No. I and in the same direction, traversing 50 ft. of gneiss before it reached the peridotite. At this point the latter formation showed only scattered blebs of sulphides, not of commercial grade. To the west, on the same contour line as No. I tunnel, and 800 ft. around the hillside from it, No. 3 tunnel was driven 50 ft. into the hill to explore a strong gossan outcrop that assayed 0.5 per cent nickel (Fig. I). From the geological exposures on the hillside and in the tunnels, it appears that the main mass of the hill is formed of an ancient and altered gneiss complex. Into this, a sill-like injection of amphibolite (altered peridotite) was intruded, which, at least in some places, contains commercial quantities of nickel sulphide. Its structure is obscure, but it appears to dip into the hill at an angle of about 15°. In the vicinity of No. 3 tunnel a large dike of quartz diorite cuts the peridotite or amphibolite; about 140 ft. north of the portal of the tunnel, a dike of andesite 00 ft. wide cuts boldly up the hillside to break the continuity of the peridotite in that direction. The geological evidence available was not adequate to decide whether the peridotite forms a continuous sill, or occurs as isolated bodies in the gneiss. Not all of this peridotite carries commercial amounts of pentlandite, but if the mineral-

Jan 1, 1946

By Ernest N. Patty, Sherwin F. Kelly

The present case history deals with the examination of an almost forgotten nickel prospect, near Winesap, Chelan County, Washington. Although the final results yielded no ore body of commercial importance, the integration of surface and underground exploration, geophysical survey and diamond drilling endow the story with interest. The program is significant because it is illustrative of how the most disappointing expenditures in mining exploration, the "not-finding" costs, could have been reduced had geophysical methods been applied at an appropriate stage in the prospecting work. The Chelan nickel deposit was discovered about 1900, on a sage-brush-covered hillside with a southerly slope, adjacent to Winesap Canyon; the paved highway now extending from Wenatchee northward, up the Columbia River and into Okanogan Valley, is only a mile away. After the deposit was found, three short prospect tunnels were driven into it, and the prospect then remained dormant for 40 years. No. x tunnel was 80 ft. long, running north into the hillside. For the first 35 ft. this adit exposed a typical, iron-stained gossan with streaks and stains of malachite, and small seams of water-soluble nickel sulphate. Beyond this, it encountered a relatively fresh peridotite, well mineralized with blebs of pentlandite. Systematic sampling yielded an average assay of 1.5 per cent nickel and 0.3 per cent copper. Down the hillside to the south and 35 ft. lower in elevation, No. 2 tunnel was driven under No. I and in the same direction, traversing 50 ft. of gneiss before it reached the peridotite. At this point the latter formation showed only scattered blebs of sulphides, not of commercial grade. To the west, on the same contour line as No. I tunnel, and 800 ft. around the hillside from it, No. 3 tunnel was driven 50 ft. into the hill to explore a strong gossan outcrop that assayed 0.5 per cent nickel (Fig. I). From the geological exposures on the hillside and in the tunnels, it appears that the main mass of the hill is formed of an ancient and altered gneiss complex. Into this, a sill-like injection of amphibolite (altered peridotite) was intruded, which, at least in some places, contains commercial quantities of nickel sulphide. Its structure is obscure, but it appears to dip into the hill at an angle of about 15°. In the vicinity of No. 3 tunnel a large dike of quartz diorite cuts the peridotite or amphibolite; about 140 ft. north of the portal of the tunnel, a dike of andesite 00 ft. wide cuts boldly up the hillside to break the continuity of the peridotite in that direction. The geological evidence available was not adequate to decide whether the peridotite forms a continuous sill, or occurs as isolated bodies in the gneiss. Not all of this peridotite carries commercial amounts of pentlandite, but if the mineral-

Jan 1, 1946

By Carl F. Floe, John Chipman

A YEAR ago the authors published a paper on the solubility of sulphur dioxide in molten copper.1 The data in that paper agreed closely with that obtained by previous investigators, which, however, did not agree with the theoretical predictions for solubility of triatomic gases of this type. It has generally been assumed that the reaction of solution is: [ ] Neglecting the slight change in copper concentration and considering that the concentrations of sulphur and oxygen are both proportional to the volume of gas absorbed, it follows that this volume should be proportional to the cube root of the pressure. It was found that a plot of the volume absorbed versus the cube root of the pressure gave a straight line, but that this line did not pass through the origin. Calculations of the equilibrium constant for the reaction showed that it was fairly constant for pressures above l00 mm. but that actually it approached zero at lower pressures. The conclusion was made therefore that the solubility as determined could not be expressed by Eq. I or by any other simple equation, particularly at low pressures. Other investigators have concluded that the solubility of sulphur dioxide in copper as well as in several copper alloys is more nearly proportional to the square root of the pressure.* Such a conclusion, however, does not satisfactorily account for the results, even when rather complicated mechanisms for the solution are assumed. The highly improbable speculations of Lepp2 and of Schneider and Esch3 based upon hypothetical dissociation pressures of Cu20 and (a; 2S dissolved in copper illustrate the type of reasoning that has been used to account for the discrepancy. In the discussion of the previous paper, the authors pointed out that the discrepancy might possibly be due to impurities in the copper, although the purest form available was used. Further consideration of the problem suggested that the impurities likely to have the greatest effect on the solubility of SO2 in copper were oxygen, sulphur and carbon. Accordingly, further experiments have been made to show the effects of these elements. EXPERIMENTAL METHODS The apparatus used for measuring solubility was essentially the same as that shown in the previous paper. However, since it was desired to make measurements at low pressures, a McLeod gauge was added and 6-mm. glass tubing was substituted for the capillary. This increased the "hot volume" considerably but was necessary in order to obtain good vacuums in a reasonable length of time. A mercury diffusion pump was also installed.

Jan 1, 1942

By J. Randel Hill

The 64th Texas Legislature passed the "Texas Surface Mining and Reclamation Act," Chapter 131, Texas Natural Resources Code (subsequently referred to as "the Act"), at a point in time when little surface mining had taken place within the state. Thus, enactment of regulatory control governing mining operations in our state has, for the most part, preceded widespread, intensive mining activity. I should point out that the statute applies only to the extraction of coal, lignite, uranium and uranium ore. A recent opinion rendered by the Attorney General's office has stated that extraction of the named elements, when it occurs incidental to the extraction of other materials, e.g., clay, is not not an activity subject to the Act. An important theme of the Act, frequently overlooked in other environmentally oriented legislation, is recognition of the Act's affect on the mining industry. The Act states that "the extraction of minerals by surface mining operations is a basic and essential activity making an important contribution to the economic well-being of the state and nation" and, in reference to reclamation being accomplished contemporaneously with mining, provides a recognition that "the extraction of minerals by responsible mining operations is an essential and beneficial economic activity." This legislative recognition is, of course balanced against the need for proper mined land reclamation, the rights of surface owners, the need to guard against unreasonable degradation to land and water resources and numerous other actions or events that the Legislature wanted protected. Another rather pervasive general theme that is established in the Act is the concept that the agency is entitled to obtain whatever information, or take whatever action, that appears reasonably necessary to effectuate the purposes of the Act. This concept, coupled with the detailed requirements placed on mining operations in the portions of the Act dealing with Permit Applications, Reclamation Plan and Reclamation Standards, easily insures that surface mining activities can and will be regulated to the extent necessary. Section 131.102(b)(2) is probably the most relevant provision in the Act which deals with the preclusion of mined lands becoming waste lands. This portion of the Act states that the surface mining operator shall: ". . . restore the land affected to the same or a substantially beneficial condition. ." In this language the Legislature had made it abundantly clear that the abandoned or orphaned lands found in some of the Eastern states, will not be tolerated in this State, and provided the Commission with a degree of latitude to determine what condition would be appropriate in each individual mining situation. I bring this area of the Act to your attention because it is the area which has received the most inquiries and concern by operators, i.e. what does "substantially beneficial" constitute? The Commission's staff has spent a considerable amount of time wrestling with the statutory language "substantially beneficial" to determine the legislative intent and provide operators with guidance of what they can expect. In this regard, the most definitive criteria in our opinion lies in the Act's legislative hsitory. The Legislature had before it basically three reclamation standards namely: House Bill 656, considered to provide the most stringent reclamation standard and identical to Senate Bill 66; House Bill 1717 which was supported by industry spokesmen and was considered to contain the least stringent reclamation standard; and Senate Bill 55 which was adopted by the Legislature. During the Bill's initial hearing before the House Environmental Affairs Committee, the House sponsor of the Senate Bill 55, which was the Bill eventually adopted, made the following statement: (I am quoting verbatim from the Committee's transcript although substituting the speaker's reference to the authors names with the Bill's numbers.) "An example of the differing approaches of the four bills can be seen in the area of reclamation standards and this is critical. House Bill 656, talking about restoring the surface of the land, House Bill 656 has this statement: 'At least fully capable of supporting the use to which it was capable of supporting prior to any mining or any higher or better use.' In other words you have to restore it to the level it was prior to the mining. Senate Bill 55: 'Restore the land to the same or substantially beneficial use.' Substantially beneficial use. (Emphasis his) House Bill 1717 says: 'Restore insofar as practical to appropriate beneficial post-mining use.' So that House Bill 1717 said to, 'restore insofar as practical to appropriate beneficial use. I think that's too weak, whereas I think the House Bill 656 that would call you to restore it to at least the use it had prior to the mining may also be too tight the other way. I think the Senate Bill 55 approach is down the middle of the road which says that you do restore it to the 'same or substantially beneficial use,' is a proper way to go there." Therefore, the conclusion that we have drawn from the legislative history of the bill is that the extent of reclamation required by "substantially beneficial" may be something other than the use it was prior to

Jan 1, 1979

By Otto W. Nuttli

The magnetic method of prospecting is well suited to determination of faulting in the basement rock. In addition to establishing the horizontal position of the fault, it often furnishes valuable information concerning the depth and amount of faulting. Consider a simple case of a vertical fault, represented in cross-section in Fig. 1. Let AA' represent the plane of observation (ordinarily the surface of the earth), and BB'B"B"' the upper surface of the basement. Assume that the sedimentary rocks are nonmagnetic, so that the magnetic susceptibility of the material above the basement is zero. Let k indicate the susceptibility of the basement rock, a- the density contrast between it and the neighboring sedimentary rocks, and t the amount of vertical displacement.

Jun 1, 1955

By J. B. Bassett, E. S. Rowland

The experimental work reported herein firas inspired by the publication of a paper by Grange and stewart, in which it was suggested that at low chromium contents the effect of this element on the Ma point was greater than at higher chromium contents, It was argued that, if a small increase of chromium in solution in austenite caused a sharp lowering of the M, point, it might lead to an explanation of occasional unsolved stress cracking of SAE 52100 during heat treatment. Commercial hardening is carried out at temperatures of incomplete solution, leaving carbides available to enrich the austenite during any inadvertent increase in temperature, such enrichment of the austenite in chromium content would lower the M, point nearer room temperature where cracking is more likely to occur. According, it was decided to investigate the effect of chromium, in quantities between o and 2 pet, on the M, point of commercial steels. Fig I summarizes the data available on chromium steels. For purposes of comparison, the M, temperature values were corrected by means of the Grange and Stewart formulas to (I) Hypoeutectoid compositions: 0.50 pct carbon and 0.80 pct manganese (z) Hsereutectoid compos-sition': 1." pet carbon and O.35 pct manganese. Only the steels having compositions reasonably close to these corrected values were included, because large adjustments inevitably introduce increased error such as are experienced in using the formula. The straight lines of Fig I were drawn by the authors. These data obviously do not settle the question Of the effect Of chromium On the Md Oint, particularly at low chromium contents. While it is fairly well established that chromium causes the M, to be lowered when present in quantities of I pet Or more, Grange and Stewart1 have suggested that in small amounts (less than 1 pet) it is more effective in lowering the Ma point, while Klier and Troiano2 have suggested that in small amounts it is less effective in lowering the Ma point. Payson and Savage3 concur with Klier and Troiano and further suggest that the effect is not linear at these concentrations. Rose and Fischer4 report that small amounts of chromium actually raise the Ma point of a 0.20 carbon steel. Material Two series of 35 Ib induction heats were melted for this work, the analyses of which are given in Table I. One series was aimed at 0.50 pct carbon and 0.80 pct manganese with chromium additions in 0,25 pet increments from o to 1.5 pct with a single heat at 2.0 pct Cr. This series was considered necessary because the commercial heat treatment of SAE 52100 does not generally introduce more than about 0.60 pct carbon in solution in the austenite. The high

Jan 1, 1949

By Irving M. Symonds

COMPA[N]IA Minera de Penoles, S. A., at its Avalos unit operates a lead-zinc concentrator having a capacity of about 600 short tons per day. Lead and zinc concentrates are made by flotation methods. The concentrator is at Terminal de Providencia, in the state of Zacatecas, some 70 miles south of Saltillo, Coahuila. The Pe[n]oles-Avalos railroad operating between the plant and Estacion Avalos, a distance of 6 miles, makes connections with the Coahuila and Zacatecas railroad, which in turn connects with the Nacionales de Mexico at Saltillo. The three railroads are each of different gauge, requiring the transfer of all supplies and concentrates at each junction. The mill operates on company ores, on ores from leased mines, and as a custom mill. The custom business is very small. The lead concentrates are shipped to company smelters at Monterrey, Nuevo Leon and Torréon, Coahuila. Since the European war, all zinc concentrates have been shipped to the United States. ORE TREATED The major source of ore supply is a group of four mines owned or leased by the company, some three miles south of the mill in the mountains, from which the ore is delivered to the mill by a gravity aerial tramway. Custom ore comes in by rail. The ores occur in chimneys. The upper levels contained oxidized siliceous ores of lead, copper, silver and gold, with varying amounts of zinc. These ores were direct-smelted. In the first two years of operation a good deal of the tailing loss was caused by the oxidized content of the ores milled. Much of the ore in the transition zones between the oxides and sulphides was not mined. The ores now being milled are clean, hard sulphides in a limestone gangue, with only occasional contamination of oxides. The lead and zinc sulphides are of coarse structure and are freed even above flotation sizes. The galena is usually "steel" colored, easily and quickly floated. When there is any oxidation, it is usually on the coarsest crystals. The zinc minerals vary a good deal in color; a resin sphalerite predominates but there are varying shades of brown marmatites. On an average, the zinc sulphides contain 64 per cent zinc. The only common copper mineral is chalcopyrite. Little is known of the occurrence of gold and silver. Waste minerals are mainly limestone and pyrite, both of which are barren. The ores vary from 20 to 35 per cent pyrite. Mill heads for the year 1940 and the first eight months of 1941 are given in Table I. [ ]

Jan 1, 1942

By Jose A. Ruiz

INTRODUCTION For heterogeneous non-catalytic solid-gas reactions carried out in fluidized bed reactors, nominal bed temperature is an average value between gas and solid. For highly exothermic reactions, actual particle temperature can be up to hundred degrees above termocouple temperature, since heat dissipate at slower rate than heat generation during some steps of transformation. These micro instabilities at particle level can displace thermodynamic equilibrium from the desired phase to others. This effect is important when relatively narrow range of phase stability exists, like in sulphation roasting of sulphides, where bed discharge contains, in addition to the desired sulphate others metastable phases such as basic sulphate and ferrite. For example, for copper-iron sulphide concentration roasted below 680°C, no cupric ferrite is formed, as shown by Jakob et al., therefore the separate Kellogg's stability phase diagrams Cu-S-O represent the roasting (Fig.l). At temperature above this one, like 760°C for example, phase stability changes from CuSO4 to the basic sulphate Cu0•CuSO4. Solid state reaction between Cu0•CuSO4 and Fe203 also occurs to form cupric ferrite, Cu0•Fe2O3, therefore the Cu-Fe-S-O Kellogg's phase diagram of Fig. 1 (continuous line) represents this condition of roasting. Although both Cu0•CuSO4 and Cu0•Fe2O3 are metastable phases under normal operating conditions of sulphation roasting(1-10% SO2, 1-10% 02 and 680°C, points A and B,Fig. 1) sulphation of these species and particularly ferrite are slow and limited due to diffusional control. This explain why reactors discharge contains several phases: CuSO4, Cu0•CuSO4, CuO•Fe203 plus small amounts of CuS and FeS due to the baclonixed conditions of fluidized bed reactors. The presence of cuprous ferrite due to reducing conditions inside individual particles also occurs, but in very limited extent at the reaction interface, as it is demonstrated by the low soluble iron levels of calcines. On the other hand, the presence of cupric ferrites can be explained only due to the higher temperature achieved by particles, since below 680°C cupric ferrite formation does not take place. [ ] This phenomena also occurs for others non-ferrous metal sulphides concentrates roasted under sulphation conditions, such as 7n, Co and Ni. Therefore the prediction of discharge composition of fluidized beds is not possible based only on kinetics and mechanistics models alone or purely thermodynamical considerations, since all factors should be integrated to describe the overall phenomena. SINGLE PARTICLE TRANSFORMATION Assuming a first order reaction with respect to the gas and zero for solid, such as

Jan 1, 1984

By W. E. Ruder

IT has been pointed out by Stead 1 that grains of considerable coarseness may be developed in steels containing from 3 to 5 per cent. of silicon, and in a previous paper 2 the present author has shown that under the proper conditions of annealing single grains having an area of 50 sq. cm. may be obtained. It is the purpose of this paper to discuss in more detail the conditions, promoting the growth of these grains, in the hope that the experiments described may throw some additional light upon the general problem of grain growth in metals. These silicon steels lend themselves particularly well to such experiments because of the ease with which the change in structure may be followed and because of the fact that the effect of the carbon present is largely obliterated by the high percentage of silicon. This forms a solid solution with the iron, which acts very much like a pure metal. This alloy has been found to have but one critical point, viz., Are. This point, determined by Roberts-Austen for Hadfield's 4 per cent. Si alloy, was found to lie at 703° C. Vigouroux3, in working with pure Fe-Si alloys, finds this point to rise from 750° C. for 0.5 per cent. Si to 860° for 6 per cent alloy, with a flat region in the curve from 3 to 4 per cent. Si. No accurate determination of this point has been undertaken by the present author, but it has been roughly determined to lie between 730° and 750°.

Jan 12, 1913

By M. Bourgon

The conductivity of liquid copper sulfide has been measured as a function of the mole fraction of sulfur in the melt at three temperatures: 1170°, 1250°, and 1300°C. The results show that a) the conductivity of copper-rich Cu,S is independent of the sulfur pressure in the furnace, and b) the conductivity of sulfur-rich copper sulfide increases rapidly with sulfur pressure. Assuming that the band theory is applicable to liquids leads to the conclusion that copper-rich copper sulfide is an intrinsic semiconductor, in which case electrons act as carriers. The activation energy for conduction in this case has been calculated to be 0.7 ev. On the other hand, sulfur-rich copper sulfide behaves as a p-type semiconductor, positive holes being responsible for conduction. IN order to elucidate the structure of Liquid copper (1) sulfide, Derge, Pound, and Osuchl have studied the electrical conductivity of this compound as a function of temperature. Their results showed that the conductivity is rather high, of the order of 100 ohm" cm", and that the temperature coefficient of conductivity is positive. This high conductivity seemed to indicate electronic rather than ionic conduction. This conclusion was checked further by Derge, Pound, and Yang,2 who measured the current efficiencies of copper sulfide melts at various temperatures. In all cases, the current efficiency was found to be nil, indicating the absence of appreciable ionic contribution to the conduction in

Jan 1, 1958

By S. R. Goodman, Hsun Hu

The formation of secondary - recrystallization tex-tlires in cube-textured 18-8 stain less steel (Type 304) Ilas been studied at three temperatures. Prolonged annealing at 100°'C protluces a PredoninanGly (520) [OOZJ-type texture, which is related to the cube te.ture of the primary lnatrix by a rotation of approxivzately 22 deg around the [001] axis in the rolling direction. Annealing at 1200 or 1300°C facers the formation of the (123)[272/-type texture, which is related to the matrix texture by a [111] rotation of app.voxiniately 40 deg. These observations suggest that in the secondary recrystallization of cube-texlut-ed stainless steel an apparent actilation energy for growth is higher for grains related to the tncrtuix Og [111] rotations thun those reloted by [100] rotations. THE formation of secondary-recrystallization textures in cube-textured primary matrices of fcc metals has been studied widely by various investigators. For Fe-40 pct Ni alloys, Pawlek' and wassermann2 reported that the orientations of secondary grains were related to the cube texture by rotations of 30 and 38 deg around [001] in the rolling direction. However, Rathenau and custers3 found that, while in one Fe-48 pct Ni alloy, most of the secondary grains were oriented with respect to the cube-textured matrix by rotations around [001] of 26.5 deg, in another alloy of a different origin, the orientations of secondary grains were related to the cube texture by rotations of approximately 35 deg around a [lll] axis. Similar orientation relationships were also observed between the secondary grains and the cube-textured primary matrices of copper.4"a No attempt was made to differentiate these two types of orientation relationships; reorientation by either a [111] or a [100] rotation was considered to be equally favored. The present investigation consisted of a study of the secondary recrystallization textures in cube-textured stainless steel. It was noted that the secondary grains formed in stainless steel were considerably smaller than those of Fe-Ni alloys or copper. This offered the advantage that the secondary recrystallization texture could be determined by the texture-goniometer technique, and a more detailed study of the textural development during the course of secondary recrystallization could be made. The effect of annealing temperature on the formation of secondary-recrystallization textures was also investigated. MATERLAL AND METHOD It was shown earlier"-" that a strong cube texture can be obtained in 18-8 stainless steels by rolling at 800°C to produce the copper-type deformation texture, followed by annealing at 800" to 1000°C for recrystallization. To improve the cube texture for the present study, a commercial-grade 18-8 stainless steel (Type 304) was rolled at 800°C first to 5 mm (0.2 in.) thick plates. Three of these plates were then stacked and welded together along the edges into a sandwich assembly. After annealing at 900°C for 20 min: the assembly was finally rolled at 800'C to 90 pct reduction in thickness with reheats and end-for-end reversals after each pass. Only the central strip, which was reduced from 5.0 to 0.50 mm (0.7 in. to 0.020 in.) thick, was used. The chemical composition of the steel in weight percent was as follows: C, 0.06; Mn, 0.38: Cr, 18.71; Ni, 9.56: P, 0.011; S, 0.009; and Si, 0.39. The purpose of rolling the strip in a sandwich assembly was to prevent direct contact between the central strip and the rolls. It was observed earlier" that, when the strip was rolled at 800°C without being enclosed in a sandwich assembly, the cube texture obtained by subsequent annealing at 900" or 1000° C for recrystallization was largely confined to the central section of the strip, while most of the recrystallized grains formed in the surface section of the strip were not cube-textured. This was obviously due to the fact that the actual temperature at the strip surface during rolling, as a result of direct contact between the strip and the cold and massive rolls, was considerably lower than 800°C. By using a sandwich assembly for hot rolling, the cube texture obtained upon subsequent annealing for recrystallization was found to extend through the entire thickness of the strip. After rolling, the central strip was taken from the sandwich assembly. and cut into specimens. Prior to annealing. the specimens were etched to 0.25 mm (0.010 in.) thick. A tube furnace provided with a purified, dry argon atmosphere was used for annealing. Textures were determined by the reflection technique. using a Siemens automatic texture-goniometer and ZrOz-filtered MoKa radiation. With a time constant of 4 sec. the preferred orientation of the secondary grains could be measured satisfactorily by the integrated intensities. Both (111) and (200) reflections were measured, and corresponding pole figures were constructed according to the techniques described previously.10 The agreement between results deduced from these two reflections was excellent. RESULTS AND DISCUSSION Secondary-Recrystallization Texture due to Prolonged Annealing at 1000°C. Fig. 1 shows the primary-recrystallization texture of a specimen annealed at 1000°C for 30 min. A substantial improvement in both sharpness and intensity of the cube texture, owing to the present processing method, can be noted readily by comparing Fig. 1 with similar pole figures shown earlier in Refs. 9 and 11. Secondary recrystallization

Jan 1, 1967

GEORGE OTIS SMITH, the Institute's new presi-dent, continues the long tradition of close asso-ciation between the organization and economic geology. Several preceding presidents have been eco-nomic geologists, and a gen-erous share of space in the TRANSACTIONS has always been devoted to that subject, one of critical importance to the miner as well as the seeker for ore. Mr. Smith has long served the Institute, hav-ing been a director since 1921 and first vice-president since 1927. He was born in Hodg-don, Me., on Feb. 22, 1871, and graduated at Colby College, where he took his A.B. and A.M. He did graduate work at Johns Hopkins, where he re-ceived a Ph.D. in 1896. Meanwhile he had engaged in field geological work in Michi-gan, Utah and Washington with the Geological Survey. In 1896 he joined the regular staff of that organization, be-coming director in 1907. He has been with the Survey con-tinuously since he first joined, with the exception of one year when he was furloughed to serve as a member of the U. S. Coal Commission. His special interest for many years has been in the eco-nomic aspects, in the larger sense, of the mineral in-dustry, matters that are necessarily the subject of strong differences of opinion, but which he has dis-cussed with good temper though with full adherence to his strong con-victions.

Jan 3, 1928

By M. M. Neale

The pottery department has been aptly described as the "heart of the zinc plant," md every operator of a horizontal-retort plant is acquainted with the fact that good retort practice is the keystone of the smelting process. Since retorts and condensers are clay products, it is obvious that improvements in other branches of the ceramic industry should be observed for possible adoption in the pottery process for zinc smelting. Deaeration of clay bodies is one of the improvements that have become fully, established in many brick and pottery plants. Our investigation of a number of these installations always yielded the same answer—improved practice. Improvement in workability, elimination of laminations, less porosity, greater wet and dry strength, were among the claims put forth for this process. All of these features are exceedingly desirable characteristics in the manufacture of a zinc retort. A preliminary test, which involved truck transportation of deaired slugs over a relatively long distance, did show the value of many of these characteristics in forming the retort. Results from the standpoint of , longer retort life in the smelting furnace were not outstanding. The idea lay dormant for several years but was revived again in 1940, when it was decided to make whatever changes were necessary in the equipment for pottery manufacture to fully demonstrate the process. A number of the manu- facturers of machinery for clay work were asked to submit proposals, and the plan finally adopted was extremely simple and economical. Machine FOR DeaeRRATING Selection of the ''Straight-line'' principle for conversion of the "Wettengel" pug mill to a ''vacuum-extrusion" machine preserved some usable parts of the original equipment, such as the drive mechanism, and main shaft. The converted machine consists of a feed hopper, a compression and shredding zone, a vacuum chamber, and an extrusion barrel, as shown in Fig. I. In operation the clay mix travels from the feed hopper into the compression zone, where it is compressed and finally forced around the tapered cone into the vacuum chamber. As it enters this chamber the clay body is shredded into thin plates, for exFosure to the vacuum. The shredder consists of a hub mounted on the main shaft, to which are bolted segmental sections, each of which carries shredder knives. The compression zone and extrusion barrel function as seals for the vacuum chamber and the shredded clay mix is agitated thoroughly during its exposure to the vacuum. A vacuum pump, equipped with a 3-hp. motor, is attached to this chamber, and maintains 25 to 26 in. vacuum during operation of the mill. Changes in Practice Prior to the adoption of the deaeration process, our standard pottery practice called for double mixing in the combination 7

Jan 1, 1944

By M. Cohen, D. J. Blickwede

Quantitative observations concerning the carbide phases in high speed steel are of importance for two general reasons: (1) the carbides, being inevitable constituents of the final structure, exert a direct influence on the properties of the steel; and (2) a substantial proportion of the total alloy content is tied-up in the carbides, and hence the extent of their solution on austenitizing governs the composition of the steel matrix. The latter relationship has a vital bearing on the response of the steel to tempering as well as on its performance in subsequent service. Accordingly, in the course of a long-term study of the behavior of high speed steels, the authors were confronted with the problem of securing quantitative data on the carbide phases. The obvious method for acquiring such information is to isolate the car-bides from the steel and subject them to chemical, X ray diffraction and other measurements. There are well-known extraction techniques which involve the chemical or electrolytic solution of the less noble matrix (ferrite, marten-site or austenite), thus leaving a residue of the carbide phases. However, the results obtained must be scrutinized carefully1,2 since the carbides may be affected by the chemical or electrolytic action. It is the purpose of the present paper to describe the experiments leading to an electrolytic-extraction technique for quantitatively isolating the carbides from both I and hardened high speed steel. Particular attention is paid to the amount, as well as the composition, of the carbides so that the matrix analysis becomes ascertainable by subtraction from the overall steel composition. Illustrative results are given for the M-2 grade of tungsten-molybdenum steel. Review of the Literature The chemical method of dissolving the matrix selectively with respect to the carbides makes use of dilute non- oxidizing reagents such as hydrochloric or sulphuric acid. Although this simple procedure has led to the determination of the cementite composition,3,4 it achieved only limited success because of the interaction between the acid and the carbide residue. Some of the carbides may not only be destroyed in this way, but the hydrogen released is likely to remove part of their carbon as hydrocarbon gases. The electrolytic technique of isolating carbides has the advantage of rapidly dissolving the specimen (anode) in the presence of less reactive solutions than are practicable with the chemical method. This reduces the possibility of chemical attack on the carbides, and furthermore, the hydrogen evolved during the electrolysis is released at the cathode which is not in close proximity to the carbides. The common electrolytes adopted for this purpose are hydrochloric and sulphuric acids.5-l1 Aqueous solutions of ferrous salts have also been used.12,13 A considerable advance in experimental technique was introduced by Treje and Benedicks14 who developed a double-compartment cell for electrolytic extraction, the anode and cathode chambers being separated by a porous diaphragm. A solution of 15 pct sodium citrate, 2 pct potassium bromide and 1 pct potassium iodide was selected for the anolyte, while the catholyte consisted of a 10 pct solution of copper sulphate, with copper serving as the cathode. This type of cell has a number of desirable characteristics: 1. The anolyte has a pH value close to 7, at least at the beginning of the run. 2. The iron that dissolves from the anode-specimen forms a water-soluble complex ion with the citrate, thereby preventing the precipitation of iron hydroxide (which would contaminate the carbide residue) despite the neutrality of the solution. 3. Copper deposition instead of hydrogen evolution occurs at the cathode, and this avoids an increasing concentration of hy-droxyl ions which (in an otherwise neutral solution) might cause the precipitation of insoluble hydroxides. 4. Contamination of the anode chamber by copper sulphate is inhibited by the porous diaphragm. Houdremont and coworkers15 applied the above method (with the further refinement of excluding oxygen during the electrolysis, washing and drying) to the extraction of carbides from a series of plain carbon steels after various heat treatments. They had quantitative success only with specimens in the annealed condition, and concluded that the size and shape of the carbide particles play an important role in the isolation process, with large spheroids exhibiting the least tendency to decompose during the electrolysis. Up to the present time, the citrate double-cell has not been used to any extent for isolating the carbides of high alloy steels, apparently on the grounds that the complex carbides are more resistant than cementite to attack in the simpler acid electrolytes. In particular, Bain and Grossmann7 and Gulyaev10.10a have employed the hydrochloric acid cell for their investigations of the carbides in high speed steel.* It will be demonstrated here that this type of cell is capable of yielding quantitative results in the case of high speed steel, and actually has certain advantages over the more complicated double cell. However, in order to provide a rigorous test of the quanti-tativeness of electrolytic procedures for the problem at hand, both methods were studied in considerable detail.

Jan 1, 1950

By P. Greenfield, C. C. Smith, A. M. Taylor

The Mg-Zr alloy ZA and Mg-Mn alloy AM503(S) are shown to have a markedly improved resistance to creep deformation after suitable heat treatments. This improvement makes them suitable for certain stress-bearing fuel element components in nuclear reactors. The extent of strengthening is described and an explanation of the behavior of both materials is given, based on a combination of strain-aging and grain growth. The increase in operating temperatures of fuel element components in Calder Hall type nuclear reactors has necessitated the development of magnesium base alloys with a very high resistance to creep at temperatures up to 500°C. Such alloys are not required for fuel element cans, which require high-creep ductility rather than strength, but for can supporting and stabilizing components, which are needed to support the imposed loads without deforming more than about 1 pct in times of up to 40,000 hr. The amount and type of alloying addition made to magnesium for these parts is limited by the necessity of keeping the cross-section to thermal neutrons as low as possible. The alloys must also possess a high resistance to oxidation in CO2. Alloys which have been developed for this application include ZA, an alloy of magnesium with 0.5 to 0.7 pct Zr and AM503(S), an alloy of magnesium with 0.5 to 0.75 pct Mn. In the as-extruded condition these alloys are very weak and ductile in creep but it has been found that they can be strengthened to a significant extent by heat treatment. This paper describes the method of developing a high-creep resistance in ZA and AM503(S), the extent of the strengthening produced and discusses the probable mechanisms of strengthening. TEST MATERIALS Specimens were taken from typical casts of ZA and AM503(S) alloys extruded into 2 1/4-in.-diam bars, supplied by Magnesium Elektron Ltd. Typical analyses of the bars were as follows: The as-extruded mean grain diameter was 0.001 to 0.002 in. for the ZA alloy and 0.003 in. for the AM503(S) alloy. EXPERIMENTAL METHODS Extruded bars of ZA alloy, 2 1/4 in. in diameter and 9 in. long, were heat treated in electrical resistance furnaces in an atmosphere of flowing CO2 containing 50 to 300 ppm water, thereby reducing the extent of oxidation compared with that which would have occurred in air. Heat treatments were carried out at 600oc for times of 8, 24, 48, 72, and 96 hr and material was subsequently both furnace cooled and water quenched. In order to measure the effect of time of heat treatment, specimens were creep tested at 400°C and 336 psi for about 1000 hr. Subsequently, the behavior of material heat treated for 96 hr at 600°C and furnace cooled was tested at a variety of stresses from 200° to 500°C. Tests were also conducted at 200o and 400°C on material in the as-extruded condition for comparative purposes. With the AM503(S) alloy, only the effect of heat treatment at 565°C for 4 hr was examined. It has been shown1 that such a heat treatment produces marked strengthening in this alloy. Tests on this material were conducted at a variety of stresses at 200°, 300°, and 400oc with comparative tests on as-extruded material at 200o and 400°C. The creep tests were carried out on machines using dead-weight loading and direct micrometer strain measurements on specimens 5 in. long and 0.357 in. diameter. At temperatures of 400° C and below, the creep tests were conducted in air, but at higher temperatures an atmosphere of CO2 was used. Grain size measurements were made on ZA in the extruded and heat treated states and on each specimen after creep testing. This was done by a line count of a minimum of 20 grains in two or three random fields in the longitudinal and transverse directions. The same method was used for measuring the grain size of as-extruded AM503(S), but the grain size of the heat treated material was so large that this method could not be employed. For heat-treated AM503(S) the large grained characteristics (between 0.1 and 1 in.) were confirmed by the measurement of individual grains. In the case of the ZA alloy, specimens taken from various stages in the program were analysed for hydrogen by a combustion method. Material in various states was also analysed for the soluble and insoluble zirconium content by dissolving in dilute hydrochloric acid. This technique has been useda for the determination of amounts of zirconium present

Jan 1, 1962

By C. Kremer Bain

DURING the past several years of diamond drilling in Washington County, Mo., the St. Joseph Lead Co. has discovered a concentration of commercial lead-zinc ore at four different points within an area of 36 square miles. The largest and to date the most promising group of these orebodies is located in the Indian Creek area. It was considered to be of sufficient value to warrant development.

Jan 9, 1953

TEE Institute assembled on Wednesday evening at the Western University, and was called to order by President Raymond. Mr. James Park, Jr., of Pittsburgh, made the address of welcome, which was responded to by President Raymond. The Council reported the following names, with approval, for election : Ashburner, William, . . . . . San Francisco, Cal. Asmus, George, . . . . . . New York. Baillie, Nathaniel, . . . . . Uniontown, Pa. Bowie, A. J., Jr., . . . . . San Francisco, Gal. Brown, A. J., . . . . . . Treasure City, Nev. Butler, J. G., Jr., . . . . . Youngstown, Ohio. Chamberlin, J. G., . . . . . Leetonia, Ohio. Clark, R. Neileon, . . . . . Canyon City, Colorado. Cornell, A. B., . , . . . . Youngstown, Ohio. De Crano, E. C., . . . . . San Francisco, Cal. Engelmann, H., . . . . . . Salt Lake City, Utah. Faber du Faur, A., . , . . . New York. Janin, Louie, Jr., . . . . . San Francisco, Cal. Johnson, George J., . . . . . Salt Lake City, Utah., Kent, Joseph C., . . . . . Phillipsburgh, N. J. Kent, William St. G., . . . . Phillipsburgh, N. J. Liebenau, Charles von, . . . . Silver City, Idaho. McClintock, A. H., . . . . . Wilkes-Barre, Pa. Miller, Thomas N., . . . . . Pittsburgh, Pa. Millholland, James A., , . . . Mount Savage, Md. Peters, Ed. D., Jr., . . . . . Dudley, Colorado. Reese, Jacob, . . . . . . Pittsburgh, Pa. Schirmer, J. F. L., . . . . . Denver, Colorado. Smith, W. S., . . . . . . Fairplay, Colorado. Stoelting, Hermann, . . . . . Georgetown, Colorado. Sweet, W. A., . . . . . . Syracuse, N. Y. Tripple, Alexander, . . . . . New York. Van Arsdale, W. H., . . . . . Swansea, Cal. Willard, Dwight D., . . . . . Bordentown, N. J. The following resolution was then offered and passed : Resolved, That gentlemen present, not members, be invited to take part in the discussions of the Institute at the various sessions of the present meeting.

By W. A. Sheaffer

Electric furnace installation and tough-pitch copper-casting operation at Canadian Copper Refiners Ltd. are described. General layout, power supply and control, refractories, induction pour hearth, casting equipment, metal temperature control, and oxygen-content control are discussed. E LECTRIC furnace at Canadian Copper Refiners Ltd. was put into operation in August 1949. The installation was designed primarily to melt electrolytic copper cathodes and to produce vertically cast tough-pitch shapes. To meet emergencies during reverberatory furnace shut-downs, provision was made for casting horizontal tough-pitch wire bars. Due to the ease with which metal temperatures, melting rates, oxygen content, and casting hours can be altered to suit production demands, the electric furnace has met the requirements admirably. General Layout The plant has been described by H. S. McKnight' and by J. H. Schloen and E. M. Elkin.2 Since these papers were written, the electric furnace has been installed in a 140 ft extension of the original casting building. The extension, 264 ft in width, is divided into one 24 ft and four 60 ft bays, each a continuation of similar bays in the older building. Fig. l, a partial floor plan of the extension, shows the location of major equipment. Power Supply and Control Power for the electric furnace and its auxiliary equipment is delivered by Quebec Hydro over two 12 kv three-phase, 60 cycle pole lines. One line is in use, while the second serves as an emergency standby. Connections for the electric furnace from these lines, which also feed the refinery power house, are made to a substation on Canadian Copper Refiners Ltd. property. Connections between this substation and the furnace transformer room are in underground conduit. The are-furnace transformer, 550 v auxiliary-equipment transformer, and 12 kv switchgear are in the transformer room near the furnace. Stepdown from 12 kv to are-furnace voltages is done by a 7500 kva oil-immersed water-cooled three-phase 60 cycle transformer. This unusually high kva rating is available because the arc furnace and transformer were adapted from a steel-melting unit. Secondary voltages are available in 16 steps between 251 and 95 v (across phases). A four-position tap changer, operated from the furnace switchboard is connected to taps yielding 199, 164.5, 127, and 115 v, respectively. The transformer primary feeder is equipped with a General Electric Magne-Blast circuit breaker. The pour hearth, casting wheel, bosh conveyor, and other auxiliary equipment are fed by a 12 kv to 550 v, 750 kva three-phase 60 cycle transformer. Graphite electrodes, 14 in., with tapered nipples are held in the are-furnace electrode arms with steel wedges. The arms, fed from the transformer secondary busbars by flexible cable bundles, are actuated by winch cables. Direct-current motors operating the winches are supplied by a 250 v motor-generator set. Power input to the furnace is controlled from the furnace switchboard. The board has the usual combination of remote controls for the 12 kv breaker and transformer tap changer, meters, overload relays, automatic and manual electrode motion controls, switchgear, etc. When power is on the furnace, automatic electrode feed is used; the power draw on a given voltage tap then is governed by current-limiting rheostats. The rheostats work through a Westinghouse bal-lanced-beam control circuit which, in turn, operates reversing contactors in the winch motor circuits. Arc Furnace The arc furnace is a standard-type NT Pittsburgh 'Lectromelt with inside shell diameter 12 ft 3¾ in. By hydraulic-lift cylinders, the furnace can be tilted forward to 39 ½ ° and backward to 5" from horizontal. A roof-swing cylinder is also installed but not used. Fig. 2 shows refractory-lining details. With the lining as shown, operating life between repairs is 6 to 9 months of two-shift casting operation. Charge slot, skim door, and roof refractories then are replaced completely, and any necessary repairs made to side walls. Bottom life is longer and the original under courses are still in service, while the top course was replaced in October 1951. The launder is lined with high chrome-magnesite trough brick backed by fireclay and insulating brick. The trough is covered with fireclay brick and asbestos sheet. At intervals, openings 12x6 in. are left in the permanent covering. These are covered with

Jan 1, 1956

By P. M. Robinson, J. S. LI. Leach

The heats of solution oj' indiurrr, tin, lend, nrzd tellurium have been calculated from the measured heat effects when mechanical mixtres of indium and telLuium tin and tellurium, and lead and tellurium were added to liquid bismuth. The results are in good agreement xith publislzed values.s for the separate sollction of each eleltzent in bismuth. The heats oj solution of cadmium and tellurium calculated from the rneasuved heat effects on adding trechanical mixtures of these elements do not ugree zc,itl the published values jbv the separate solution of each element. It is shown that at 623°K Ile interaction between cadmium and tellurium dissolved in liquid bismuth is strong enough to led lo preciPitation of solid CdTc. The heats oj- jor-mation of CdTe at 273" nd 623°K (1)-c crilculated fi-or the measured heat ejlfecls. The calcnlaled az'erage deviation from the Kopp-l\'ez?,zunrz rule fov solid CdTe is less than 0.06 cat per g-atom- C over this lertzperalure range. Tlze importance 0.f these oDserl.ations to the determination of heals of formation hy metal solution calorimetry is considered. LIQUID metal solution calorimetry is a convenient method for determining the heats of formation of solid compounds. In this technique the heat of formation is the difference between the measured heat effects on dissolution of the compounds and of mechanical mixtures of the components in the liquid metal.' The heat of solution of the mechanical mixture may be calculated from the measured heat effect. At infinite dilution of the solutes, this heat of solution is equal to the sum of the heats of solution of the separate components. If the heat of solution of one of the components is known, the value for the other can be derived; if both are known, they may be used to check the accuracy of the calorimetric technique. The heats of formation of the tellurides of cadmium, indium, tin, and lead have recently been measured by metal solution alorimetr. The heats of solution of indium, tin, lead, and tellurium at infinite dilution in liquid bismuth at 623"K, calculated from the measured heat effects on solution of the mechanical mixtures, are in good agreement with the published values. The heats of solution of cadmium and of tellurium calculated from the measured heat effect on solution in bismuth at 623'K of mechanical mixtures of cadmium and tellurium, however, do not agree with values estimated from the literature. 1) EXPERIMENTAL PROCEDURE AND RESULTS The Heats of Solution of Indium, Tin, Lead, and Tellurium in Bismuth. The heat effects were measured when mechanical mixtures corresponding to the compounds In,Te, InTe, In2Te3, In2Te5, SnTe, and PbTe were dissolved in bismuth. The calorimetric procedure and the method of calculation have been described elsewhere.' The heats of solution of the mechanical mixtures were obtained by subtracting the change in heat content per gram-atom of the sample between the addition temperature (273°K) and the bath temperature (623"K), (H623°K - H273°K)S, from the measured heat effects. The calorimeter was calibrated with pure bismuth. The reported values of the measured heat effects are based on (HGoK - ^273oK)Bi = 4.96 kcal per g-atom.3 The measured heat effects are found to be linear functions of the solute concentrations of the bath in the dilute solution range. The values, extrapolated to infinite dilution, are listed in Table I, together with the heats of solution of the mechanical mixtures calculated using the published values of (H 623°K - H273°k)s for indium, tin, lead,3 and tellrium. All the error limits quoted in this work represent the spread of values obtained. The heats of solution in liquid bismuth at 623°K of mechanical mixtures of indium and tellurium in four different proportions were determined. Values of the heats of solution of the two components were then calculated from the resulting four simultaneous equations: The heats of solution at infinite dilution of tin and lead in liquid bismuth at 623°K were calculated from the heats of solution of the mechanical mixtures of tin and tellurium and of lead and tellurium using the heat of solution of tellurium calculated above. These values of the heats of solution are listed in Table I1 together with some published values for comparison.

Jan 1, 1967