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By H. F. Ramstad, F. D. Richardson

The equilibria (a) SiOz +Hz =SiO +H20 and (b) Si + SiO, = 2Si0 have beet1 studied at temperatures of 1425"to 1600°C ad 1310°to 1485°C respectively. The stattdard free energy changes for the tzrro reactions are given by the equatiotts Combination of the results for both equilibria leads to tiotz removes certain anomalies in existing high-terlzperature data for equilibria involving silica and silicon in iron. In many metallurgical processes and in many laboratory investigations silicon monoxide undoubtedly plays an important role. It is unfortunate therefore that wide differences exist between the results obtained by different investigators1-7 in their studies of such equilibria as In an attempt to put our knowledge of SiO on a surer basis, an exhaustive study has been made of equilibria [I] and [2] at temperatures ranging from 1300" to 1600°C. Reaction [I] was studied by measuring the amounts of silica which could be condensed from streams of Hz or Hz + HzO which had previously been brought into equilibrium with silica at temperatures ranging from 1425" to 1600°C. Reaction [2] was studied by measuring the material that could be condensed from streams of Hz or argon which had been brought into equilibrium with mixtures of silicon and silica at temperatures ranging from 1310" to 1485°C. EXPERIMENTAL Materials. The silicon was "superpure" grade and contained less than 0.1 pct impurities. The silica was prepared from pure mineral quartz; this was crushed and treated with concentrated hydrochloric acid to remove particles of iron, washed with water, and finally dried at 120°C. For the hydrogen + silica reaction, the silica was sized to —20+100 mesh. For the silicon + silica reaction, the two materials were ground to a fine powder in an agate mortar. The hydrogen and argon were commercial oxygen-free gases. The gas streams were controlled with capillary flow meters and the volumes were measured by wet gas meters. After passing through the meters, the gases were partially dried by silica gel. The hydrogen for the HZ + SiOz reaction was then passed through palladised asbestos at 300°C and dried with magnesium perchlorate. The efficiency of oxygen removal was checked throughout the experiments by passing the gas over an electrically heated strip of nichrome, used as an indicator as described by Rathman and de itt.' When mixtures of HZ + Hz0 were required, the partial pressures of water vapor (1.8 to 22 mm) were obtained by passing the hydrogen through oxalic acid dihydrateg' lo held at various controlled temperatures, O.l°C, by means of a water bath. The hydrogen for the Si + Si02 reaction was purified by passing it over a mixture of 3 parts of magnesium to 5 of lime heated to 600°."l1 u The argon for this reaction was passed through titanium powder (-3/16 in. + 100 mesh) heated to 900°C. The nitrogen used to prevent the reaction products escaping from the condenser (see later), was deoxidized by copper or iron at 600°C. All these gases were finally dried with magnesium perchlorate. Furnace, Temperature Contr01, and Measurement A molybdenum resistance furnace was used for both sets of experiments. The reactions were conducted inside a high-grade alumina tube, 36 in. long and 1 in. in diam as indicated in Fig. 1. With this arrangement an even temperature zone (2"C) 4 cm long was satisfactorily obtained. The temperatures were kept constant by means of a proportional controller actuated by a Pt-Pt 13 pct Rh thermocouple. This was placed between the two alumina tubes, so that the temperature at the junction was 1400" to 1450°C. Up to 1485"C, the temperatures were measured with Pt-Pt 13 pct Rh thermocouples. For higher temperatures an optical pyrometer was used, this being sighted (through the glass window 1 in Fig. 1) on the end of the alumina tube, that held the SiOz or Si +SiOz mixture, 10 in Fig. 1. The optical pyrometer was recalibrated whenever a change was made in any part of the apparatus situated in the hot zone. Successive readings with the optical pyrometer were reproducible to within 1"C. Equilibrium Apparatus and Procedure. Hydvogen and Silica Reaction. The apparatus is shown in Fig.

Jan 1, 1962

By G. W. Elger, H. E. Bell, J. E. Tress, J. B. Wright

This paper describes laboratory techniques and subsequent results of US Bureau of Mines (USBM) research to produce chlorination-grade feed- stock from an abundant, low-grade, domestic, rock ilmenite ore. The research is part of the Bureau effort to devise technology that may help decrease US dependence on imported raw materials. A rock ilmenite containing about 46 wt % TiO2 was smelted in an electric arc furnace with coke, wood-chips, and Na2CO3 to separate most of the iron as pig iron and to form a low-iron, titanium-enriched slug. The slug was ground, pelletized, oxidized, and then sulfated with mixtures of SO2 and air in a continuous 4.5- to 9.1-kg/h (10- to 20-lb per hour) apparatus at 1023° to 122J0 K (1380° to 1740° F). The sulfated slug, containing 60% to 65% TiOb, was reground and leached in water at ambient temperature to decrease the combined levels of the troublesome calcium, magnesium, and manganese impurities from 7.0 to 1.7 wt 70. The final product was upgraded to about 8.4 wt % TiO2. This material is potentially suitable for chlorination in a fluidized bed reactor. The most favorable results were achieved with leached slug sulfated at a feed rate of 4.5 kg/h (10 lb per hour) and at temperatures of 1073° to 1123° K (1470° to 1560' F).

Jan 1, 1986

R. V. NorHis, Wilkes-Barre, Pa. (communication to the Secretary*) : The electric-haulage plant of the Short Mountain Colliery of the Lykens Valley Coal Co., mentioned by Messrs. Stoek and Harris as the earliest underground electric plant in the United States (and, I believe, the second in the world), was started July 23, 1887. The plant, designed by W. M. Schlessinger, consists of two motor-cars, each weighing about 5 tons and equipped with a 32-h.p. Union Electric Go. motor. The original general construction of the motor-cars is shown by Mr. Stoek; but they were rebuilt, the same year, with some important improvements in design; and, except for strengthening the frames and replacing the original pig-iron weights by a casting, they have not been greatly changed since that time. The generating-plant consists of two Union Electric Co. dynamos of 65-h.p. each, driven by an old 18- by 48-in. plain slide-valve engine; the ordinary voltage is 450 and the amperage varies from 40 to 200; the average indicated h.p. of the engine is about 75, with a steam-consumption of about 75 lb. per i.h.p. per hour; and as the cost of steam at this colliery is 8.11 cents per 1,000 lb.,the steam-cost per day is about $4.56.

Jan 1, 1904

By John C. LaScola, David M. Hyman, William P. Diamond

The U.S. Department of the Interior, Bureau of Mines, has established a computer-implemented coalbed methane data base containing data representing over 2,000 coal samples from approximately 250 coalbeds located in 17 States and one Canadian Province. Space for approximately 130 sample characteristics is reserved for each sample record and is divided for access efficiency into three separate physical files. A software package was written to provide a user-friendly environment in which the three files can be manipulated simultaneously. These files can be used interactively in DATATRIEVE 11, a commercially available sorting, retrieval, and report-writing software package or in any FORTRAN-compatible system for statistical analysis. The data base has been established for coalbed methane research in response to the health and safety needs of the mining industry. Possible applications of the data base include mine planning related to the occurrence of gas, as well as delineating areas of resource recovery and utilization.

Jan 1, 1983

By M. F. Trice

PYROPHYLLITE is a hydrous aluminum silicate (A12Si4O10(OH)2)1 that occurs in both the foliated and the massive forms. The foliated variety resembles talc in that it has a greasy feel, a pearly luster, perfect basal cleavage, and usually is white, although in some deposits apple green, gray, brown, russet, and nearly black specimens may be found. The massive deposits of pyrophyllite yield pearl gray to light tan aggregates, some of which are so friable that they may be crushed with the hands into a fine gritty powder. Frequently specimens of the massive variety are studded with crystals of radial structure. The mineral has a specific gravity of about 2.7 and a hardness of 1 on Mohs' scale.1 The chemical composition of commercial pyrophyllite reflects the mineralogy of the deposits, which, according to Stuckey,2 contain pyrophyllite and quartz, together with chloritoid, sericite, and a few other minerals of negligible importance. The latter, he says, "are noticed in but small quantities to the extent they might occur as accessory constituents of an igneous rock or as products of regional metamorphism or weathering. . . . Quartz is abundant everywhere except in the very best grades of pyrophyllite." Analyses of specimens from several deposits are listed in Table 1, showing that the silica content varies from 57 to 73 per cent and the alumina from 22 to 33 per cent. Oxides of iron and the alkaline metals are collectively present, with one exception, to an extent of about 1 to 1.5 per cent. SOURCES At present, North Carolina is the only commercial source of pyrophyllite, although the mineral has been found in small quantities in many parts of the world. The North Carolina deposits are in the "Carolina Slate Belt," which traverses the center of the state in a southwesterly direction. This

Jan 1, 1940

By D. Walton

The effect of small solute additions of Cu on the activation energies for creep A1 single crystals were determined over the range from 78° to 850° K. Below 240°K and above 800°K activation energies were unchanged. Between 240°K and 400°K strain aging causes the creep rate to become vanishingly small and the flow stress was independent of the temperature. Between 500° and 50°K the activation energy was increased to 41,000 cal per mole. NUMEROUS investigationsL have shown that solid solution alloying invariably increases the flow stress. A typical example is documented in Fig. 1. Such increases in flow stress can arise from two general effects: Alloying can increase the long-range stress fields through which dislocations must move by causing appropriate clustering; modification of dislocation densities, and so forth. Alloying can also modify the short-range stress fields that determine the activation energies for thermally stimulated migration of dislocations, such as occurs in some solute atom pinning processes, and so forth. Actually both long- and short-range stress-field effects can occur simultaneously. It was the purpose of this investigation to evaluate the effect of alloying on the short-range stress fields by determining the effect of alloying on the activation energies for creep. The resulting observations also shed some light on the effect of long-range stress fields on dislocation processes. EXPERIMENTAL TECHNIQUE Single-crystal bars (6 in. long 3/8 in. wide and l/4 in. thick) of dilute solutions of Cu in A1 were seeded, so as to provide extensive single slip, with the pole of the tensile axis located in the standard stereographic projection as shown in Fig. 2. Each crystal was grown under an argon atmosphere in a graphite mold containing a large reservoir of molten alloy for the purpose of obtaining rather uniform composition of Cu along the length of the bar. The nominal compositions of the alloys which were produced from 99.99 pct Cu and high-purity A1 containing 0.001 pct Fe and 0.001 pct Si, are given in Table I. Strains, measured by linear variable transformers attached by quartz rods to a 3 in. gage section were sensitive to and the stresses were ap- plied by direct loading of the specimen. Temperatures were determined by thermocouples attached to the gage section of the specimens. Below 400°K the apparent activation energies for creep, Q, were determined by the effect of small, rapid changes in temperature of about + 10°K from T1 to T2 on the corresponding creep rates ?1 and ?2 during primary creep according to where R is the gas constant.' Above 400°K, Q was evaluated from Eq. [1] for the secondary creep rate using temperature changes of about ±20K. A typical set of results is shown in Fig. 3. RESULTS AND DISCUSSION The previously obtained effect of temperature on the apparent activation energy for creep of single crystals of high-purity A12 is shown by the broken curve of Fig. 4. The datum points on the same graph illustrate the effect of dilute a solid solution alloying with Cu on the activation energy between 600" and 750°K. Each plotted point is the average of not less than five independent test values between 600° and 750°K and not less than three at other tempera-

Jan 1, 1962

By P. T. Carter, A. B. Murad, H. B. Bell

The distribution of manganese and oxygen between molten iron and FeO-MnO-SiO2 slags not saturated with SiO2 has been determined and used to calculate activities of MnO and SiO2 in MnO-SiO2 slags. These were found to be intermediate between the corresponding activities in FeO-SiO2 and CaO-SiO2 slags. THE equilibrium constant for the reaction between molten iron containing manganese and slags containing FeO and MnO, namely: FeO(slag) + Mn = MnO (slag) + Fe(1iquid) is most conveniently represented by: (MnO) Kmn== (FeOHMn] [Fe] is omitted, since for dilute solutions of manganese in iron, afe is approximately constant. When activities are used for (MnO), (FeO) and [Mn], Kmn is a true equilibrium constant and will apply to all types of slags, but when weight percentages are used, the values obtained for Kmn for different slags vary considerably. The equilibrium between iron containing manganese and relatively pure FeO-MnO slags has been investigated by several workers;1-4 the most recent investigation reported is that of Chipman, Gero, and Winkler.4 Their results, corresponding to slags containing up to 4 pct SiO2, were represented by the equation: 6440 log KMn = +2.95 In this case both slag and metal may be assumed to be ideal solutions, therefore the values of Kmn so derived represent the true constant for the manganese reaction. As the molecular weights of MnO and FeO are almost equal, weight concentration of these oxides may also be used in the above expression. Acidic oxides such as SiO2 and P2O5 affect the activities of FeO and MnO differently, so that when total concentrations by weight of FeO and MnO are used in the above expression for Kmn the values obtained are no longer constant. These will be denoted by K'mn. Körber and Oelsen5 investigated the manganese reaction using silica-saturated iron-manganese-silicate slags and found: 7940 logK'mn =3.172 This corresponds to Kmn values much higher than those obtained for pure oxide slags. The results of Körber and Oelsen, and Chipman, Gero, and Winkler are summarized in Table I. In the present investigation it was decided to study the manganese reaction using iron-manganese-silicate slags not saturated with silica, and which fell mainly between the orthosilicate join 2FeO . SiO2 - 2MnO.SiO2 and the FeO-MnO side of the ternary system FeO-MnO-SiO2. It has been shown" that the phases present in solidified slags of this part of the diagram are (FeO, MnO) and (2Fe0.Si02, 2Mn0-SiO,) solid solutions. Such an investigation would be of interest in deoxidation and also gives information on activities in liquid slags. This equilibrium has not as yet been investigated successfully. Hilty and Crafts7 attempted to examine this reaction in a rotating crucible furnace, but were unable to obtain suitable slag samples. In the present investigation one series of experiments was carried out in a rotating crucible furnace, because the success of Taylor and Chipman8 with such a furnace in their study of oxygen distribution between molten iron and (CaO, MgO) — FeO-Si0, slags suggested that it would minimize contamination of the slag by the crucible material. A second series was carried out using a wire-wound resistance furnace. Rotating Crucible Furnace Experiments In all cases the metallic charge consisted of 800 to 1000 g Armco iron containing 0.02 pct C, 0.03 pct Mn, and traces of Si. Manganese and silicon additions consisted of electrolytic manganese (99.9 pct)

Jan 1, 1953

By H. C. Chang, N. J. Grant, A. R. Chaudhuri

During the creep of coarse-grained polycrystalline magnesium at elevated temperatures, a nonbasal type of slip was found to play an important role in the deformation processes. The nonbasal slip traces were examined metallographically in eight specimens (13 grains) and the observed glide plane located stereographically for each grain. The tests were run at 500&apos; and 700°F at stresses of 148 to 786 psi. Based on these measurements and theoretical calculations, the crystallographic elements for nonbasal slip were determined. WHEN a metal deforms by slip, the conventional appearance of the slip bands on the surface of a specimen is that of straight lines. Such is the behavior of the face-centered-cubic metals, as for example, aluminum. The particular slip system on which slip occurs in these metals is governed by the criterion of resolved shear stress. Work on the body-centered-cubic metals a-iron,&apos;. &apos; molybdenum, and columbium4 has shown that the process of slip is somewhat more complicated than the simple gliding of one close-packed plane of atoms over another in a close-packed direction and that it results in the formation of wavy and irregular slip traces on the surface. The recent reviews and experiments of Vogel and Brick and Chen and Mad-din3 show that, for the body-centered-cubic metals, the resolved shear stresses along the planes and the degree of close-packing do not necessarily determine the slip system. Theirs and other investigations indicate that a complete understanding of the slip process in the body-centered-cubic metals is not yet possible. However, one behavior displayed by all these metals is that the slip direction is invariably one of the close-packed directions <11l>. The wavy nature of the slip-band traces has been explained on the basis of cooperative slip by planes sharing this same slip direction.1&apos;3l&apos; It is generally acknowledged that, when the hexagonal-close-packed metal magnesium (axial ratio c/a = 1.624) deforms by slip at room temperature, it does so by basal slip in the close-packed direction <1I%>. This type of slip has the conventional appearance of straight lines and is governed by the critical shear-stress law. Schmid and coworkers" showed that basal slip was operative in the temperature range of —185" to 300°C (—300" to 572°F). Work by Servi, Norton, and Grant6 has shown that, during the creep of coarse-grained aluminum at high temperatures, new slip systems come into operation. The existence of a new high temperature slip system at temperatures greater than 225 °C (437°F) for magnesium was suggested also by Schmid. This was later indicated by Bakarian and Mathewson&apos; to be slip along the pyramidal planes (10i1) in the close-packed direction <11%>.* They * Mention will be made in the text of pyramidal planes and prismatic planes. The pyramidal planes referred to are the type I. order 1 of the form {10il); and the prismatic planes of the type 1 of the form (10i0). For the sake of brevity, they are termed in the teat as pyramidal (10il: and prismatic (10i0) planes, respectively. Where reference is made to the pyramidal plane type 1, order 2 of the form {10i2), they are referred to as the pyramidal planes of the type (10i2:. observed that this kind of slip resulted in irregular markings on the specimen surface. According to them, a possible cause for the appearance of the markings was due to "limited accessory slip on the pyramidal {10i2) planes." Burke and Hibbard," on deforming a single crystal of magnesium at room temperature, found evidence of slip on a pyramidal plane {1011). They explained it as being due to the effect of grip restraints. It is pertinent to note at this point that, although basal slip has received a fair amount of attention, only two specimens have been investigated, that of Bakarian and Mathewson and of Burke and Hibbard, to establish the elements of nonbasal slip in magnesium. During the study of the deformation mechanisms

Jan 1, 1956

The official Institute reports for the year 1929 were distributed in pamphlet form at the Annual Meeting, February, 1930, and were later included in Section 2 of Mining and Metallurgy, June, 1930, and thus made available to the entire membership. Membership In its report the Admissions Committee set forth the changes in membership during 1929, as follows: Total membership, Jan. 1, 1928, 8582; elected and placed on rolls in 1929, including 59 reinstatements, 509; loss by resignations in 1929, 88; loss by death in 1929, 110; loss by suspension in 1929, 37; membership at end of year not including Student Associates, 8856. Distribution of membership: Honorary Members, 16; Members, 6590; Junior Members, 38; Associates, 1041; Junior Associates, 1033; Rocky Mountain, 138; total membership, Jan. 1, 1930, 8856; Student Associates, 150; total including student associates, 9006. Treasurer&apos;s Annual Report, Year of 1929 Statement of Receipts For the year ended December 31, 1929 Dues: Arrears............................................ $ 3,501.75 Current............................................ 97,257.12 New Members...................................... 5,721.50 Advance........................................... 1,970.79 $108,451.16 Initiation Fees.................................................. 7,436.00 Magazine Receipts: Advertising Gross Receipts........................... $40,610.81 Magazine Sales..................................... 3,799.84 44,410.65 Sale of Transactions Current........................... $ 2,985. 15 Sale of Special Editions Current........................ 5,147.82 Sale of Back Transactions and Special Editions........... 4,186.93 Sale of Year Book..................................... 65.50 Sale of Authors&apos; Reprints.............................. 2,585.40 Sale of Pins and Fobs.................................. 14.73 Sale of Technical Publications.......................... 1,451.55 Sale of Bindings...................................... 3,949.13 20,376.21 Net Interest Received: On Bank Balance and Temporary Investments......... $ 2,595.04 On Lie Membership Fund........................... 3,223.43 On James Douglas Library Fund...................... 5,425.61 On General Reserve Fund............................ 2,015.58 13,259.66 Miscellaneous Receipts........................................... 335.80 Total Receipts................................................ $194,269.48

Jan 1, 1930

The official Institute reports for the year 1929 were distributed in pamphlet form at the Annual Meeting, February, 1930, and were later included in Section 2 of Mining and Metallurgy, June, 1930, and thus made available to the entire membership. Membership In its report the Admissions Committee set forth the changes in membership during 1929, as follows: Total membership, Jan. 1, 1928, 8582; elected and placed on rolls in 1929, including 59 reinstatements, 509; loss by resignations in 1929, 88; loss by death in 1929, 110; loss by suspension in 1929, 37; membership at end of year not including Student Associates, 8856. Distribution of membership: Honorary Members, 16; Members, 6590; Junior Members, 38; Associates, 1041; Junior Associates, 1033; Rocky Mountain, 138; total membership, Jan. 1, 1930, 8856; Student Associates, 150; total including student associates, 9006. Treasurer&apos;s Annual Report, Year of 1929 Statement of Receipts For the year ended December 31, 1929 Dues: Arrears............................................ $ 3,501.75 Current............................................ 97,257.12 New Members...................................... 5,721.50 Advance........................................... 1,970.79 $108,451.16 Initiation Fees.................................................. 7,436.OO Magazine Receipts: Advertising Gross Receipts........................... $40,610.81 Magazine Sales..................................... 3,799.84 44,410.65 Sale of Transactions Current........................... $ 2,985. 15 Sale of Special Editions Current........................ 5,147.82 Sale of Back Transactions and Special Editions........... 4,186.93 Sale of Year Book..................................... 65.50 Sale of Authors&apos; Reprints.............................. 2,585.40 Sale of Pins and Fobs.................................. 14.73 Sale of Technical Publications.......................... 1,451.55 Sale of Bindings...................................... 3,949.13 20,376.21 Net Interest Received: On Bank Balance and Temporary Investments......... $ 2,595.04 On Lie Membership Fund........................... 3,223.43 On James Douglas Library Fund...................... 5,425.61 On General Reserve Fund............................ 2,015.58 13,259.66 Miscellaneous Receipts........................................... 335.80 Total Receipts................................................ $194,269.48

Jan 1, 1930

By A. D. Bryant

APPROXIMATELY 2 1/2 million tons of silica sand and ground silica with a value of $7.25 million is produced annually from the Ottawa, Illinois, district. These silica products come from the well known St. Peter sandstone formation which covers part of the Mississippi Basin extending from St. Paul on the north to the central part of Arkansas on the south and from Muncie, Ind., on the east to Kansas City on the west. Practically the whole state of Illinois is underlain by this formation except where removed by erosion. Sand produced from the St. Peter sandstone in the Ottawa district is noted for its purity, uniformity, and quality. In addition to various screened grades for industry about 10 pct of the total production of the Ottawa district is ground into silica flour for use in glass, abrasives, enamel, porcelain, tile, for foundry and filter sand, and other uses.

Jan 3, 1953

By B. W. Adams, R. W. Shilling

9.4-1. Basic principles. DESCRIPTION AND BASIC FUNCTIONS. The concept of inclined skip haulage is not new. The basic idea has been in use at least 400 years. The system is essentially a steeply inclined railway utilizing a hoist to pull the skips to the top or intermediate positions. Inclined skip haulage is often justified where high lifts would require long hauls for other haulage systems. The basic system types are as follows: 1. Single skip, single drum. This system is a single car pulled by a simple hoist system. 2. Balanced skip, single drum. A system utilizing two cars (skips on cables)--one overwound, one underwound-on a single drum. The dead weight of one skip and cable balances the dead weight of the other. As one skip ascends the other descends between two fixed points. 3. Balanced skip, double drum. This system is an elaboration of system No. 2, except the drums may be disengaged from one another to permit the skips to service various loading and dumping points. The preceding are major classifications subject to numerous variations. These variations may be in the skipway, skip design, loading methods, or unloading methods. A few examples follow: 1. The skipway may be standard or special railroad, an overhead monorail or cable, or a ramp for rubber tired vehicles. 2. The skip, per se, may be of varying dumping arrangements (side, bottom, etc.) or could be the box of the vehicle hauling to the skip. 3. Loading may be accomplished directly from the service unit to skip, through an intermediate loading device (e.g., a pocket), or into bins which feed the skip. Loading may be at more than one point. 4. Unloading of the skip can be simple or complex as required. Dumping may be to the haulage unit, to bins and feeders, or to a crusher and conveyor system. Dumping may take place at more than one point.

Jan 1, 1968

By Franklin J. Kay

Introduction The methods used in surface, mining vary throughout the world, depending on many variables such as: the types of over- burden materials, the depth of the overburden, the thickness of the seam, and other operational choices, both financial and functional. However, the stripping machines are typically draglines, stripping shovels, excavators, scrapers, loaders, and bulldozers. In all cases the economic feasibility of mining thin seams depends on the market needs, the market location, the equipment used, the mine management, the quality of the coal, and the labor market. Slight negative combinations of these parameters have closed many mines while positive combinations allow others to exist. The limited mobility or slow movement of large stripping shovels, draglines, and bucket wheel excavators make them more economically fitted to areas where large quantities of overburden are to be moved. This is necessary to keep the transfer and setup time between pits a negligibly small percent of the total operational time. Equipment such as the scrapers, loaders, backhoes, trucks, and bulldozers that are either very mobile or can be trailered is more versatile and can be used in the smaller area mines.* Mobile equipment is also more practical in areas with shallow overburden because of the constant movement required while removing overburden. In thin coal seams the equipment is usually paired such that the operational equipment can be listed as: (1) dragline-loader, (2) shovel-truck- loader, (3) scraper-loader. (4) loader-truck-loader, or (5) loader-loader. In these operations the overburden is removed with the first machine(s) of the pairing and the loader or loaders are used for coal production. Recent articles in Coal Age (Chironis, 1978) and Mining Engineering (Wiebmer, 1978) have discussed varying philosophies in mining similar seams of coal. One operator uses draglines for competitive mining while the other uses scrapers for the same purpose. Both cite strong cases sup- porting their choice of equipment as good sound economic decisions and their success supports their choices. The drag-line operation is adding new larger draglines to decrease the cost of mining, rather than to increase coal production. The scraper operation has also gone to more and larger scrapers for basically the same reasons. These operations and all

Jan 1, 1981

By J. A. Putnam, A. D. K. Laird

In laboratory research on the behavior of oil, gas and water in porous materials, no direct method has been devised to measure saturation without disturbing the flow. Indirect methods involving various forms of radiation have been developed for measuring one or two components. The X-ray absorption method for two components has been described previously1-3. The possibility of three component measurement has also been mentioned1. Since two component measurement still requires considerable care to insure accuracy, the fact that three components can be measured satisfactorily is not generally appreciated. The fraction of the energy of an X-ray beam of one wavelength transmitted through a material is given by the transmission factor. in which 1 is the beam&apos;s path length through the fluid. p is the fluid density, and 1,. is its mass absorption coefficient. Eq. 1 implies that all parts of the beam pass through equal amounts of the fluid. Practical applications are, therefore, limited to systems in which the fluid is distributed so that I varies negligibly over the cross-section of the beam. Typical variations of the transmission factor with X-ray tube potential arc shown in Fig. 2 from which experimental points have been omitted for clarity. The X-ray absorption of low pressure gases in a core is practically zero so it cannot he distinguished from that a vacuum by instruments that will differentiate between liquids. The transmission factor of a gas in a core is. therefore, unity. Consequently, the saturation of only one gaseous component can be found. If two fluids completely fill a core, their two saturations add to unity and, therefore, only one value of the transmission factor, T, is needed to determine both of them. When two liquids do not completely fill the core, their saturations do not add to unity and transmission factors at two wavelengths must be measured. At one of these wavelengths, 7 for one liquid must be different from T or the other liquid. The change of T for one liquid us the wavelength is changed between the two values must be different from the corresponding change of T in the other liquid. The two values of fluid saturation will also give that of the gas because the three saturations must add to unity. In Fig. 2 it can be seen that there are many large differences of T between various oil solutions and water solutions at any one potential, and between potentials for any one solution. Consequently, conditions for optimum accuracy of measurement of the saturations of a gas and two liquids can be chosen. Once the operating potentials have been selected, however. it is more convenient to cross plot the data from Fig. 2 on transmission factor-solution concentration coordinates for the chosen potentials, as shown in Fig. 3. Fig. 3 was used to plan the experimental procedure for Core N-38-1. Since the voltage control at 45 kv was good, the slopes of the curves in Fig. 2 at this potential would cause little error. At low potentials, however, the voltage control was not good, so 33 kv was chosen because the small slopes of the curves made voltage control less critical. The lowest strength beam that could be measured reasonably at 33 kv corresponded to a minimum T factor of 0.385. Fig. 3 shows that both 4.80 weight per cent of cadmium chloride in water and 24.0 per cent of iodobenzene in crystal oil had this T value, and, consequently, were indistinguishable to the X-rays at 33 kv. Thus, at 33 kv, the liquid saturation was given by the same curve regardless of the relative amounts of oil and water solutions present. This simple calibration curve from which the gas and liquid saturation can be read, is shown in Fig. 4. Fig. 3 also shows that at 45 kv, T for the aqueous solution is 0.610. and that T for the oil solution is 0.220. These values were transferred to Fig. 4 to give the triangular calibration plot from which the brine and oil saturations can be found, after the gas saturation has been determined at 33 kv.

ON p. 499 of the December issue Of MINING AND METAL-LURGY plans were announced for a memorial to en-gineers who died in overseas service during the World War and a gift to the University of Louvain on behalf of the engineers of America. In this connection it is proposed to erect a memorial tablet giving the names. of engineers who died in the foreign service. Members of the A. I. M. E. who gave their lives, so far as they are known, are listed below. It will be much appreciated if notice be given of any omissions and also if the name of some surviving relative be supplied in each case. Louis Baird, Lieut., Royal Field Artillery, British Army, killed on the battlefield, 1915. John H. Bellamy, Capt., Regimental Staff, 103rd Engi-neers, killed near Fismes, Aug. 9, 1918. Martin F. Bowles, Lieut., 1st Battalion, 355th Infantry, 89th Division, killed on the battlefield, Sept. 3, 1918. Andrew Burt, died in .active service, 1916. Stanley B. Carlisle, Machine Gun Battalion 346, 91st Divi- sion, died in France, Oct. 24, 1918.

Jan 1, 1928

By V. H. Gottschalk

SEVERAL years ago a group in the metallurgical division of the U. S. Bureau of Mines began a study of the application of new developments in physics to metallurgical problems&apos;. Among these developments were the extensions of what may be termed by analogy the "sound spectrum." Electromagnetic waves, from X-rays to radio waves, have been quite thoroughly explored for metallurgical use, but the sound spectrum, extending from low-frequency vibrations involved in certain types of metal failure by fatigue through the range of audible sound to inaudible vibrations having frequencies of many kilocycles, has had only meager consideration from metallurgists. Because of the general interest in the process recently demonstrated by St. Clair3 for flocculating smoke by means of sound waves, this article is written to point out possible applications of sound and supersonic (ultrasonic) waves in the metallurgical industry.

Jan 1, 1937

By Chester Purington

THE AUTHOR hopes that this paper will meet with criticism and debate by fellow members of the Institute rather than with that attitude of passiv-ity and indifference which one is inclined to adopt when considering a field completely foreign to one&apos;s own experi-ence. After several years of study of voluminous literature, maps, and statistics, and many personal journeys and field inspections of various parts of Siberia, the conclusion is reached .that the area adjacent to the Stanovoi, Zhugd-Zhur, and Yablonoi ranges as below defined is that which .is most accessible to the western world and will soonest give results from exploration. HISTORY The first incursion of the Russians into Siberia east of the Yenesei River appears to have been in 1632 when the fort of Yakutsk was founded on the middle Lena. The early expeditions were in quest of furs. As the Siberians say, "the sable beckoned" and the post of Anadyr was founded in 1639, two thousand miles further northeast. Thus nineteen years after the Pilgrims landed in Massachusetts, the Russians had established a trading post within 700 miles of what is now the town of Nome, Alaska. Parties of Cossaks penetrated to the shores of the Okotsk1 Sea early in the seventeenth century, but it was not until 1688 that the town of Okotsk was founded. In 1712 a grand project was elaborated at St. Petersburg for building a port at Okotsk, but it came to nothing. Vitus Bering, the Alaska explorer, built ships at Okotsk, and made this his point of depar-ture. It is stated that the iron work used in these ships was brought overland partly from Yakutsk, and partly even from St. Petersburg, 5500 miles away. Accord-ing to report a copper deposit was worked on the river Urak, not far from the coast, and copper was smelted for sheathing the bottoms. Grassgrown mounds con-taining slag and shots of copper were inspected by the writer last summer, at the site of the ancient shipyard.

Jan 11, 1923

By George B. Lee

DURING The Two Years In Which The New Reduction-Works Of The Copper Queen Consolidated Mining Co. Have Been In Operation At Douglas, Ariz., There Has Developed A Remarkable Condition In Regard To The Corrosive Action Of The Water Used To Cool The Jackets Of The Blast-Furnaces. Were It Not For The Many Contradictory Features, It Might Pass As One Of The Unavoidable Troubles Due To The Composition Of The Water. This Water, Obtained From Wells 600 Ft. Deep, Is Also Used In The Steam-Boilers, And Its Composition, As Shown By The Following Analysis, Does Not Indicate The Presence Of Any Ingredient Which Would Explain The Corrosion Grains Per U. S. Gal. Silica, 0.861 Iron Oxide And Alumina, 0.223 Calcium Carbonate, 0.2111 Calcium Sulphate, Magnesium Carbonate, Sodium And Potassium Sulphates, . 14.850 Sodium And Potassium Chlorides, 9.732 Sodium And Potassium Carbonate, 6.452 32.409 The Jackets Are Made Of Inner Plates 0.5 In. Thick And An Outer Plate I In. Thick, With 3-In. Stiffeners Between The Inner And Outer Plates. In From 10 To 12 Months The Inner Plates Have Been Reduced By Corrosion To A Thickness Of From 1/8 To 1/16 In., While The Outer Plate In The Same Time Is Reduced By Less Than 1/16 In., And The Stiffeners Show Very Little Corrosion. The Plates Are Pitted And Eaten Away In Some Places More Than In Others. There Is Practically No Scale Found On The Jackets, But When Cleaned Considerable Iron Oxide Is Found In The Bottoms. With An Action So Marked, Serious Trouble Would Be Expected In The Boilers, But, On The Contrary, A Recent Inspection By a

Mar 1, 1908

By H. H. Stout

IN the early fall of 1925, the writer was conducting, in the Ledoux and Co. labora-tory, New York, experiments directed to-ward ascertaining the effect on its impurity content when cathode copper was subjected to a current of various gases at an elevated temperature below the melting point, The apparatus consisted of a vertical 1-in. dia. silica tube about 12 in. long, heated on the outside, The cathodes were broken to pass a8-in. mesh, and a current of various differ-ent gases was passed up through a 4-in, long column of these loose cathode particles in the vertical tube furnace. Temperature was maintained to i500° to 1600°F. and the gas treatments lasted from 3 to 6 hr, The writer observed that whenever reducing gas (H2 or CO) was used, these cathode par-ticles stuck together at points of contact with each other. The cohesion was so marked and tenacious that an examination was made of the fractured surfaces, when cathode particles were broken from the cluster. Crystal growth was always found to have taken place across the surfaces where separate particles were in contact, but only after all oxides, sulphates, etc, had been completely removed. The idea of a possible new process was then conceived and was disclosed to A. M. Smoot (V. P. Ledoux and Co.) with intent to obtain his views. The first conception as given Smoot was "to gas-clean broken cathodes, put them in an extrusion press, solidify and extrude them at around 1500°F," Smoot&apos;s reaction, after a few moments considera-tion, was, "It looks perfectly all right to me."

Jan 1, 1940

By John F. Elliott, John R. Rawling

The rate of reduction of silica to silicon by carbon at 1550° to 1700°C in iron blast-furnace type slag-metal systems has been investigated. In the tower portion of the temperature range oxygen transport in the metal boundary layer at the slag-tal interface is probably rate limiting. A second step, which apparently involves a chemical process in the slag at the slag-metal interface, appears to be rate limiting when the oxygen-transport limitation is avoided. Above 1650°C rate control of the reduction by carbon probably is mixed between the two steps. INVESTIGATIONS1.2 into the equilibrium distribution of silicon between graphite-saturated slags and metals typical of iron blast-furnace practice show that, under the experimental conditions specified, the reduction of silica to silicon is relatively slow compared with the rates of other slag-metal reactions under similar conditions. For this reason, the reduction of silica in blast-furnace slag-metal systems was considered to be an interesting subject for further study. Investigations of the kinetics of the reaction3-5 suggest that several possible steps may be rate controlling, and that the rate-controlling step depends not only on the physical state of the systems but also on the configuration of the apparatus. The main objects of the investigation reported here were to sug- gest plausible reaction paths for the reduction of silica under the experimental conditions chosen and to determine the step or steps which control the rate of reduction of silica. EXPERIMENTAL Two types of experiments involving the reduction of silica from the slag were carried out. In the first, the only reducing agent present was carbon (graphite), for which the over-all reaction is (SiO2) +2C(gr) —Si + 2Co(g) [l] The second type was a graphite-saturated ferro-silicon-iron concentration cell. In it silica in the slag could be reduced either by carbon according to Eq. [I], or by a reaction of electrochemical nature in which silicon was oxidized at the ferrosilicon-slag interface and silica was reduced at the slag-iron interface without the formation of CO. The two types of experiment are described below. Reduction of Silica with Carbon as the Only Available Reducing Agent. The reduction of silica was accomplished by allowing a liquid lime-alumina-silica slag and graphite-saturated iron to react in an induction-heated graphite crucible. The crucible was 2.25 in. diameter and 5 in. deep; it was fitted with a graphite stirrer which penetrated through the slag and into the metal, Fig. 1. The slag and metal charges weighed 350 g each. Pure carbon monoxide at a pressure of 1 atm was maintained above the melt by passing the purified gas through the crucible at a rate of 0.5 liter per min. The gas did not stir either the slag or metal. Temperature measurements were made by sighting an optical pyrometer down the hollow stirrer rod into a 1/4-in. hole drilled in the stirrer blade. The crucible temperature was maintained within *15"C of the required value by manual control of the power supply to the

Jan 1, 1965