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By S. Ramachandran, R. G. Woolery

INTRODUCTION Union Carbide is currently operating an in-situ leach project on the Palangana Dome area in Duval county. This deposit meets all the requirements for in-situ leach in that the ore (1) is below the water table, (2) is in a permeable horizon, (3) is amenable to chemical leaching, and (4) is confined by impervious layers. This project has been under commercial production since 1976, and its capacity has been expanded on three occasions since going on-stream. Recently, additional uranium reserves were discovered on the Rogers-Cardenas (R-C) property about 32 km north of the Palangana operation. The ore is located within the Oakville sands and its characteristics are quite similar to those of the ore at Palangana. Both are an unconsolidated Arkosic sand high in clay and calcium carbonate. The R-C ore, however, is somewhat coarser with a mean particle size of 0.15 mm as compared to a mean particle size of 0.07 mm for the Palangana ore. In all respects it would appear that this ore would be a candidate for in-situ leach as a satellite operation to Palangana. Unfortunately, R-C ore is above the water table and, therefore, not amenable to the Palangana practice. Because of the limited known reserves in this deposit, it is readily apparent that conventional mining and milling are out of the question. However, because of its proximity to our Palangana operation, it seemed worthwhile to consider other options. The most viable route based on our past experience was to heap leach the ore. Our recent success at our Gas Hills facility and our Maybell operation, in employing a heap leach practice to our marginal reserves seemed to be a logical approach for processing this ore. Our experiences at both locations are described in "Heap Leaching - A Case History" by R. G. Woolery et al., Mining Engineering, March 1978. In both instances the process is an acid leach circuit and acid consumption averages 20 kg/t H2SO4. A preliminary feasibility study showed that because of the high strip ratio required for the R-C project to be successful, additional ore reserves must be located and that a method of heap leaching with an alkaline circuit would have to be developed. As a result of this paper study, the decision was made to proceed with a program of additional exploration drilling to determine the total ore reserves that could be mined economically. The Mining Department will evaluate each ore zone for cutoff grade, strip ratio, and expected mining cost. At the same time, a laboratory program to evaluate the available core samples for amenability to heap leaching with respect to an estimate of uranium recovery and processing costs was developed. This program is currently in progress, and at this time, we are just completing our process amenability study. BENCH-SCALE EVALUATION OF THE R-C ORE The initial bench-scale slurry leach tests on the R-C ore showed an acid consumption in excess of 200 kg/t H2SO4. These data, of course, discouraged us from considering this process route. Not only would the acid cost be prohibitive, but the gypsum generated by the reaction of the sulfuric acid with the calcium carbonate of the ore would severely effect the percolation of the lixivant. For this reason, the laboratory program was directed toward an alkaline circuit compatible with heap leaching. Because of the proximity of the R-C property to our Palangana operation, it seemed advisable to integrate the processing of this ore into the production at Palangana. Doing so would enable us to bring the R-C property into production by merely enlarging our present facilities at Palangana; otherwise, construction of a grass roots plant would be necessary. Ideally, the simplest method would be to construct the heaps at Palangana and employ an ammonium carbonate/bicarbonate leachant compatible with the in-situ production liquor. The product liquors could then be co-mingled or processed separately as desired. To determine if this goal was practical, samples of the R-C ore were obtained, and a laboratory program initiated. Heap leach amenability testing consisted of preliminary bench-scale evaluation to determine optimum solution strength and ultimate uranium recovery, followed by small column tests to confirm the bench-scale metallurgy and to determine percolation characteristics. These bench-scale tests are being followed by pilot-scale testing approximating field conditions. As expected, the bench-scale tests showed that the dissolution rate is considerably slower for alkaline leach than has been our experience in acid leaching. Because of the slower reaction rates, product liquor grades will be lower than for acid, as greater volumes of solution are required for satisfactory uranium extractions. The greatest influence on reaction times found in the laboratory was the carbonate/bicarbonate strength and oxidant addition. However, the higher salt concentration reduced the efficiency of the IX resin circuit and about 25g/L salt proved to an upper limit compatible with subsequent IX treatment. The oxidant contributed significantly to the early extraction rate but seemed to have only minimal effect on the total practical U308 extracted or the time required to achieve it. This variable will require larger scale testing to determine if the added cost of the oxidant is actually justifiable. Thus, the small-scale laboratory slurry tests, based on the 0.088% U308 sample available, indicate that leaching at 25g/L ammonium carbonate/bicarbonate, with or without oxidant, we might expect an 80-85% U308 extraction on this ore.

Jan 1, 1979

By J. D. Price, W. M. Bertholf

W. J. PARTON*—I have not had the opportunity to read this paper, and I do not have a written discussion. However, I thought it might be interesting for me to relate some of the experiences we had with equipment similar to the vibrating filter as described by the' authors. At the Tamaqua flotation plant of the Lebigh Navigation Coal Co. approximately 40 tons per hour of froth concentrate carrying 60 pct by weight moisture are produced. The major problem encountered at this plant is the dewatering of this coal froth so that a satisfactory product can be sent to market. In the original design of the plant a centrifuge of solid bowl type was included for de-watering this material. The centrifuge did not work out as well as we had hoped. High maintenance costs and moisture content in the cake were obtained. A Robbins dewatering screen was installed at a later date with the idea of using it in conjunction with the centrifuge. The froth concentrate from the flotation cells was fed directly to the Robbins dewatering screen. The cake from the screen carried approximately 55 pct of the feed solids. Moisture in the cake was approximately 24 pct by weight. The underflow from the screen carried 45 pct of the feed tonnage at about 80 pct moisture by weight. The underflow product was then pumped into the centrifuge with the idea of using the cen-trifuge for recovering the tonnage lost through the screen. This circuit did not operate as satisfactorily as we expected. The only benefit derived was in the reduction in the power consumed by the centrifuge. The maintenance on the centrifuge was approximately the same as previously. The next step in our experiments was to pump the underflow from the screen into a cyclone thickener which was mounted directly over the vibrating screen. This thickener increased the concentration of the solids to approximately 60 pct by weight and dropped the mate- rial back 011 the filter cake which had formed toward the discharge end of the screen. Unfortunately, the screen was not capable of handling this additional tonnage, and our experiments stopped at that point. We have been considering installing a second screen to make possible the complete mechanical dewatering of this product by the use of the dewatering screen and the cyclone thickener. Another possibility under study is to pump the underflow from this screen to a thickener which is available in the flotation plant, and to combine this thickeued underflow with the original feed going to the screen. Again, however, a second dewatering screen will be required to handle the total tonnage. 0. R. LYONS*—I had an opportunity to read this paper ahead of the meeting, and I did a little pencil engineering on it. As Mr. Bertholf said, it is very difficult to make a comparison and to carry the results of work at one plant over to what might be expected at another. What I did was to find information on filtering operations more or less comparable to the type of operation that Mr. Bertholf has with his vibrating filter. The only information that I was able to find was for drum type filters, and I found the operating characteristics of the vibrating filter and the drum type filters were very similar. The moisture contents of the cakes were almost identical. The output per square foot was about the only way that I could compare their capacities— using square foot of screen area against square foot of filter area—and I found the capacity of the vibrating filter to be slightly greater per unit area than the capacity of the drum-type filters. W. H. NEWTON†—Do I understand that the only escape for the solids is by overflowing the thickener? That is, does the filter have a chance to recover all the solids except that lost in the thickener overflow ? W. M. BERTHOLF (authors' reply)— Actually, the only escapc from that part of the circuit is over the top of the thickener. There are other places the fines could be lost in the washery. but once they get into that part of the circuit, they must go over the top to escape. W. H. NEWTON—I would like to ask Mr. Lyons if, in the study of rotary filters, he has any basis for comparison of operating costs? 0. R. LYONS—No, I had no information on costs. The only information I was able to find was on screen size, moisture content, and tonnage output per unit area. W. L. McMORRIS*—Are you wasting that overflow water or re-using it? W. M. BERTHOLF—Right now, we are not re-using it. D. R. MITCHELL† —What is the approximate per capita cost of one of these units? W. M. BERTHOLF—It appears to be somewhere in the neighborhood of $200, for the screen. W. H. NEWTON—The cost would be about $2500 for the complete unit including the vibrating power unit. G. A. VISSAC‡—I do not like to come on the floor after I have been talking so long, but I thought you might be interested in our experience in dewatering, as well as drying our very fine coals. We have used both centrifuge and vibrating screens. The type of vibrating screens we have used in Canada are called the Zimmer. That is a screen of German construction, and I guess it is along the same lines as the dewatering screens you are using now. We use wedge wires, and the minimum size opening is a quarter of a millimeter. In our experience, the cheapest way is still a dewatering bin. A dewatering bin takes 48 hr to do work that takes 20 min in a dewatering screen. We use old wedge wire from our driers which we cover with brattice cloth, and

Jan 1, 1950

By E. R. Gilbert

Klopp et al. have reported data on tensile and creep properties of are-melted and electron-beam-melted tungsten. We would like to point out some similarities between their creep results and ours on are-melted and powder-metallurgy tungstenand offer some alternate interpretations of the data which lead to different rate-controlling mechanisms. Klopp et al. observed extensive transient creep in the 2250" to 3500°F temperature range where the acthetivation energy is 106,400 ± 3300 cal mole-1. They suggest cross slip as the possible rate-controlling mechanism since "cross slip may occur only by the movement of screw dislocations, and not edge dislocations, thus allowing only partial recovery of the strain hardening and resulting in a continuously decreasing creep rate, characteristic of transient creep.'' Our tests on are-melted tungsten and powder-metallurgy tungsten displayed an extensive transient creep stage in the same temperature range but they also displayed a steady-state creep stage. The stress levels and strain rates of the two investigations, 1.4 to 7 kg mm-2 and 10-7 to 10-4 sec-1 for that of Klopp et al. and 4.5 to 10 kg mm-2 and 10-8 to 10-4 sec-1 for those of Gilbert et al., are overlapping. The activation energy for creep of our powder-metallurgy tungsten is 105,000 cal mole-1. This close agreement with the value found by Klopp et al. suggests that the same mechanism may be common to both types of materials. It may be possible to gain some additional insight into the rate-controlling mechanism by applying the analysis made by conrad22 in terms of the activation volume. The value for the activation volume depends upon the dislocation mechanism and may be used to help differentiate between various dislocation mechanisms. The activation volume for cross slip is 10 to 100 b3. Values determined from our data were 130 to 220 b3 which are in better agreement with the range of 102 to 104 b3 for nonconservative motion of jogs. Values determined from data of Klopp et al. are 240 to 1040 b3. We suggest that the rate-controlling mechanism for creep in this temperature range may be nonconservative motion of jogs assisted by enhanced diffusion along grain boundaries or dislocations. This model requires an activation energy lower than that for self-diffusion as is observed. If this is the controlling mechanism, a higher activation energy which is closer to that for self-diffusion might be expected for tests conducted on specimens with reduced grain boundary area, i.e., larger grain size. In support of this premise we have conducted tests on speci- mens having one to three grains per cross section for which a higher activation energy of 130,000 cal mole-1 was observed. Also, in agreement with results of Klopp et al., a faster creep rate resulted from the increased grain size and probable decreased dislocation density. Further argument against the cross slip mechanism is based on the constant activation energy we obsserved over the range of 5.0 to 10 kg mm-2,21 whereas the activation energy for cross slip displays a significant stress dependence.23 In addition to this, the powe on the stress term for the strain-rate dependence appears too high for cross slip. The values for tungsten fall in the range of 4.5 to 7 (Klopp et al. and Ref. 21) whereas values of approximately 2 are observed in creep by cross slip for hep metals.24 At temperatures from 3300° to 4000°F, Klopp et al. observed an activation energy of 141,000 ± 4000 cal mole-' which is less than that for self-diffusion, 153,000 cal mole-1, 25 and less than that reported for high-temperature creep of powder-metallurgy tungsten by Green:' 160,000 cal mole-1. Klopp et al. suggested that recovery of strain hardening by dislocation climb is the rate-controlling mechanism in this temperature region. Actually an activation energy larger than that for self-diffusion is predicted by this model if the temperature dependence of the elastic modulus27 is taken into consideration. Klopp et al. attributed this lack of correlation to the compositional differences between powder-metallurgy tungsten used by Green and their own arc- and EB-melted tungsten. It is our position that the value of 141,000 ± 4000 cal mole-' represents a transitional value between the higher and lower activation energies and does not represent a discrete mechanism of deformation. If the tests had been extended to higher temperatures the higher value of activation energy would have been observed as has been demonstrated by both our analy sis'' of isothermal test data by GE-NMPO28 and differential temperature tests28 on are-melted tungsten. The activation energies determined (170,000 and 160,000 cal mole-1) were greater than that for self-diffusion and are in better agreement with the value found by Green. The model of dislocation climb is associated with ; activation volume of 1 b3 according to Conrad.22 The activation volume calculated for the creep data of fou independent investigators in the temperature range where the activation energy for creep is near that for self-diffusion (Klopp et al. and Refs. 26, 28, and 30) is 110 to 2800 b3 and is in the range suggested for nonconservative motion of jogs. In the case of tungsten this mechanism may be preferred over that of dislocation climb. Sincere appreciation is expressed to Messrs. J. E. Flinn and F. L. Yaggee for the helpful discussions and suggestions in the preparation of this communication.

Jan 1, 1967

By B. C. Allen

The interface energies of chronzium, molybdenunz. hugsten, and their solid-solution alloys Cv-35Re, MO-33Re, and UJ-25Re were studied at 0.6 to 1.0 of the absolllte liquidus ter)zpe,vature using fiz&apos;e )izethods. Liquid surface tension, yv , was deter mined clsing the pendant-drop and drop-weight methods. Results are, respectizlely, 1700, 2370, and 2480 +100 dynes per ct for the rhernium -containing alloys and essentially the same as tlwse reported for liquid chro)riln, trolybdenum, and tungsten. Average solid slrjace energy, rsv< xias ))zeasured using tlre fiber-extetlsion method. The ratio of ysS, the acerage high-angle grain-boundary energy, to ySV cclas jolnd fronz grain-bolzdary grooue angles fort)zed at the surface in an inert atrfizosphere. Absolllte iute?:face energies were deterawined using ?nultip/rase equilibria involzing suitable liquids of known surface tension (tin, silver). Interpretation of the experimented results in view of pvobable tenzperatzcre, orientation, and purity effects giz,e the follouling approximations in ergs per sq ctn: ysv (i2lo. Mo-33Re) - 2100, ySS (Mo, Mo-33Re) - 800, rr (defornzation twins in MO-33Re at 1200"C) - 800. ysV (Cr. Cr-35Re) - 2400. YSS (CY, Cr-35Re) - 1000. Probably Ylv- YSV- 2500 for tungsten and W-25Re, giving yss (It&apos;, W-25Re) - 900. The interface energies of solid and liqid ch?&apos;omiu?.z, nolybdenu?rr, and tungsten are not geatly aff&apos;ected by rhenium and therefore are not a ttlajor factor in the ductili zing rhenium effect in Croup VI-A metals. THE interface energies of the refractory Group VI-A metals, chromium, molybdenum, and tungsten, are not well-established. The objective of this investigation was to study the liquid surface tension, solid surface energy, and grain-boundary energy of these metals and compare them to those found for the bcc solid-solution alloys, Cr-35e,&apos; 0-33e,&apos; and -25e. Five techniques were used to measure interface energies in high-purity polycrystal rod, wire, and sheet at 0.6 to 1.0 of the absolute liquidus temperature. The alloys were chosen to see if there was any connection between interface-energy behavior and the ductilizing rhenium effecL4j5 EXPERIMENTAL WORK Materials. A description of the materials used is presented in Table I. Chromium rod was prepared by arc melting iodide process crystals supplied by Chromallo Cor., hot extruding, and warm swaging to 0.63-cm-diam rod.6 The sheet was prepared by rolling as-extruded rod to 95 pct reduction in area from a hydrogen furnace at 800" to 900°C and surface grinding off 0.02 cm from each face. Cr-35Re rod was prepared by arc melting sintered rhenium powder and iodide chromium crystals, warm rod rolling to 50 pct reduction in area in cans, and swaging to 60 pct reduction in area at 1100" to 1200°C. Some of the rod was warm-rolled to sheet and then surface-ground. Portions of swaged chromium and Cr-35Re were further reduced by swaging and drawing to 0.013-cm-diam wire by the General Electric Co. Mo-33Re and W-25Re rod, sheet, and wire were provided by Chase Brass and Copper Co. The molybdenum sheet consisted of two lots, both essentially the same except for the carbon content. Liquid Surface Tension. The liquid surface tension of Cr-35Re, Mo-33Re, and W-25Re was measured by a combination of pendant-drop and drop-weight methods using techniques already decribed." Following out-gassing, molten drops were formed on the ends of centerless-ground Mo-33Re and W-25Re rods by electron bombardment at 5 x 106 mm. Similar drops were formed on outgassed Cr-35Re rods by induction heating under 1 atm of 99.995 pct Ar. Solid Surface Energy. Solid surface energy was measured by conducting microcreep experiments on molybdenum, Mo-33Re, chromium, and Cr-35Re wires at 2350°, 2306, 1550°, and 180O°C, respectively. In preparation, gage marks -2.5 cm apart and -0.001 cm deep were circumferentially scribed on the wire with a razor blade. Weights of the wire material were then attached. Five to seven reasonably straight wires were hung in a container made out of the wire material. The free end was placed through a small hole in the removable top and secured by bending a small portion 90 deg. The containers not only tended to provide vapor-solid equilibrium for the wires but also protected them from gaseous impurities. They were nominally 2.5 cm in diam by 5 cm high and were made from extruded chromium rod, Cr-35Re arc casting, molybdenum bar stock, or welded Mo-33Re sheet. After deg re as ing, the assembly was outgassed at a relatively low temperature to 2 x 10"5 mm and then recrystallized 2 to 8 hr at the creep temperature in a rhenium-element resistance furnace. The static argon atmosphere was gettered by tantalum radiation shielding. Specimen temperature was measured optically to 25"C using calibration with known melting points and blackbody conditions. The wires generally developed a stable bamboo-type structure according to Fig, l(b), (c), and (d) and retained their gage marks [upper portion of Fig. l(d)]. One or two of the weights were clipped off to provide a low load for the creep anneal. To minimize the possibility of bending or breakage, the wires remained attached to the top of the annealing container which was held to keep the wires vertical. The distance between gage marks was

Jan 1, 1967

By JOHN JANNEY

STABILIZATION of the adjustment of normal consumption to normal production of world commodities is quite different from reducing production until visible surpluses are consumed. The first means restoration and maintenance of prosperity, the second means merely a temporary alleviation of a condition with the prime cause remaining uncorrected. Overproduction of foodstuffs in some sections of the world while millions starve in other sections represents not so much overproduction of foodstuffs as mal-distribution of foodstuffs. The flour mills of Washington and Oregon normally ship quantities of flour to China. Now, the wheat that would make this flour goes East instead of West. Is this overproduction, or is there something wrong that calls for study, analysis and correction? Can the plan used by the ostrich of hiding its head in. the sand get us by this present world tragedy, or must the challenge to solve this problem be met, constructively? Can we not make out of this breakdown in the world&apos;s economic system an opportunity? And use it as the stimulus for remedying the basic cause of the trouble and not content ourselves with devising temporary expedients that aim at remedying this or that of the obvious conditions, in themselves not causes at all but rather the evidence of causes, or that are the symptoms of the real trouble.

Jan 1, 1931

By Blandford C. Burgess

Mica is an orchid among minerals. It is formed in pegmatites, one of the most bizarre of igneous formations, and is exceeded by few other minerals in the perfection it may attain as to size, color, and cleavage. First used for window glazing, as an ornament and article of trade, it has become one of the most essential insulators of electricity, heat, and shock. Most internal combustion engines use mica condensers or capacitors and such machines of war as planes, tanks, and submarines are immobile without it. The original manuscript of this guide was written in April 1943 at the peak of war emergency. It was not used be- cause shortly thereafter a decision was made to buy on a one price basis eliminating differentials for both quality and size. This is now presented with the thought that from the standpoint of preparedness we can only consider an- other war imminent and every effort should he made to set up in usable form the experience gained during the Second World War. Colonial Mica Corp. was set up by Metals Reserve Co. as a wholly owned government agency to encourage production of domestic mica and to purchase it. It soon became the exclusive buying agency for such mica. The writer as Southern Manager called on all the private agencies buying mica to assist in formulating buying policies, methods, and prices.

Jan 1, 1949

By J. WILLIAM WETTER

WHEN the privilege was extended to me to address this meeting I could not help but make a mental review of my own activities and experiences in connection with association work. After having spent about 16 years in the mining engineering field, I entered into the operating branch of coal mining which afforded, about 12 years ago, my first opportunity of attending a meeting of our local Association and sitting in with the "big boys" of the industry. This was quite a thrilling experience because I had heard a great deal about the various operators who belonged to the Association and knew, or at least thought I knew, that a certain group dominated its affairs and that a "clique" was in control of a sizable "roller" which could be "steamed up" at will to flatten out any opposition which might appear upon the horizon or under it, too, for that matter. Now, I was to have the privilege of observing this "clique" at first hand, of seeing a small group making the policies and shaping the destinies of a great industry and planning the activities of an important Association while a large majority of the members would sit by either complacently or otherwise with the full knowledge that the "roller" was in waiting to reduce them to ribbons at the first sign of resistance.

Jan 1, 1930

H. W. Turner, San Francisco, Cal. (communication to the Secretary*): This excellent paper apparently represents the results of extensive observation and experience among the mines of the Mother-Lode, but I strongly question its relegation of the dioritic intrusions to the period of fissuring and ore-deposition. The dioritic rocks referred to are evidently those areas represented by Ransome in the Mother-Lode folio1 as meta-diorites, and, as he says, are merely basic facies of the great granodiorite batholite of the Sierra Nevada. If followed downward I venture to predict that these meta-diorite areas would be found to connect with the great batholite, and to be in fact mere apophyses of it. I see no reason for supposing that these apophyses were intruded into the Mother-Lode slates at a period later than the intrusion of the granodiorite in general. The period of fissuring was subsequent to this intrusion; the basic granodiorite or quartz-diorite areas of the foot-hill region are themselves fissured extensively; and the fissures were filled with quartz, apparently during the same general period of the formation of the Mother-Lode veins. Prichard and Ransome2 both refer to the deposition of quartz in the same lode at different periods resulting from a reopening of the fissures. Some time since, I saw in the stopes of the

Jan 1, 1904

By AIME AIME

EVER since his college days at the University of Iowa, the professional interest of Morris Morgan Leighton has centered on geology, and he now heads the State Geological Survey of Illinois. Just 52 years ago--on Aug. 4, 1887-he was born at Wellman, Iowa. He remained at the State university for his Master&apos;s degree, awarded in 1913. A two-year fellowship at the University of Chicago led to a Ph. D. degree, after which Dr. Leighton went out to Seattle as instructor in geology at the University of Washington during 1915-&apos;16. He returned to Iowa as assistant professor of geology at Iowa State Teachers&apos; College for a year, followed by another year at Seattle, after which he returned permanently to the Middle West, first as acting professor of geology at Ohio State and then, from 1919 to 1923, as assistant professor of geology at the University of Illinois and geologist for the Illinois Geological Survey. Of the latter organization he has been chief since 1923, with no present teaching duties. As a result of the successful work of the Survey, notably in non-metallics and in the initiation and stimulation of the recent oil activities in the southern part of the State, it is soon to have a new building with modern laboratory facilities.

Jan 1, 1939

By Robert Mehl

THE precipitation of the nitride Fe4N from the solid solution of nitrogen in a Fe and of the phosphide Fe3P from the solid solution of phosphorus in a Fe both lead to the formation of structures that may be easily identified as Widmanstätten figures, within the meaning of the term as used in this series of papers. A complete solution has been obtained for the figure formed by Fe4N. The structure of Fe,P, however, is not fully known and a complete solution of this figure thus cannot be obtained; nevertheless, a study of this figure has furnished some new information. PRECIPITATION OF FE4N FROM ALPHA SOLID SOLUTION OF N IN ALPHA FE Constitution of System Iron-nitrogen A knowledge of the constitution of the whole of the Fe-N system is unnecessary for this work, though the recent studies by Eisenhut and Kaupp1 and by Lehrer2 have clarified most of the moot points; it is sufficient for our purpose to state that a Fe of high purity dissolves 0.42 per cent of nitrogen in solid solution at the eutectoid temperature, 591° C., and that this solubility decreases at first rapidly and then more slowly until at room temperature the solid solubility amounts to approximately 0.1 per cent nitrogen.3

Jan 1, 1934

By Blamey Stevens

The object of this paper is to show how igneous intrusion is governed by definite mechanical laws. A distinction is made between dikes and fissures, and the various characteristics of intrusions are explained on an exact scientific basis. The modification of rock-stresses by intrusion is then considered and extensive isostress regions are recognized. Finally, a complete classification of intrusions is constructed covering all possible cases. The generalizations of observed data, taken from Geikie&apos;s Text-Book of Geology, confornl to the laws of intrusion herein stated, and the deductions based upon these lams. No authority, however, is quoted for the type which I hare named a corrugated intrusion. Its existence is a necessary deduction from the laws of intrusion, and even the entire absence of examples in technical publications cannot disprove its reality. In all probability, corrugated fissures would have remained undiscovered, but for the nrorking of mineral veins. As intrusions of tabular form are seldom worked for commercial purposes, it has been left for theory to anticipate the discovery of corrugated dikes. In the light of these laws of intrusion and the corresponding laws of fissures,&apos; there seems to be a remarkable uniformity of stress-distribution in rocks at moderate depths. This renders possible the mathematical calculation which should help us to approximate exact science in this and kindred branches of applied geology.

Jan 1, 1911

By Jerry G. Rose, Robert C. Howell

This paper addresses a process by which both the disposal and utilization of preparation plant coal refuse can be simultaneously accomplished with an attendant benefit of significantly increasing the percentage of extractable coal. A laboratory study is described in which coal refuse was successfully utilized as an aggregate in low cost concrete (coal-crete) mixes under simulated mine environments. Coal-crete specimens with compressive strengths of 14 000 kPa (2000 psd were consistently produced. A construction sequence and mining plans are offered for placing the low-cost coal-crete pillars in accessible areas in room and-pillar mines so that a substantial portion of the remaining coal pillars could be extracted. The method could be applicable in areas where mining procedures do not permit pillar extraction because of possible surface subsidence, roof problems, or other conditions. Possible structural difficulties with the coal-crete pillar support system are discussed. Using a discounted cash flow analysis, the economic feasibility of mining with the coal-crete pillar system is investigated. The cost of the system is compared to the cost of a mining system which would have less coal recovery. The analysis indicates that although at higher coal selling prices the coal-crete mining system may yield an acceptable rate of return, the alternative of leaving the coal pillars is more attractive at the present time.

Jan 1, 1980

By C. E. Julihn

Technology concerns the ways of doing things; mineral technology the ways of performing operations required for obtaining minerals from the earth and extracting their valuable constituents for man&apos;s use. At any particular time, technology is relatively fixed, as everyone tries to adopt the way of doing things that has proved most profitable; but improvements evolve from minor changes here and there, and occasion- ally entirely new methods are discovered. Technologic improvement thus characterizes any long-time view of the mineral industries. Its test lies always in reduction of costs; there is no other incentive for the adoption of new methods. Reduction in cost of producing metal from ore decreases, in turn, the amount of metal that must be obtained from ore in order to pay for its production. An advancing technology thus is characterized by utilization of ores of lower and lower grade. A very important result of this is an increase in the gross quantity of metal obtainable at any price level, since the earth&apos;s crust contains vast amounts of very low-grade ores and relatively insignificant amounts of very high-grade ores. Technologic advances have, therefore, been the means of rendering the metals both cheap and abundant. Though concern as to possible exhaustion of the world&apos;s ore deposits is warranted, it is conceivable that a transcendent technology of the future might supply metal requirements from what we

Jan 1, 1932

By J. H. Frye, S. G. Holder, E. E. Stansbury

Internal friction studies on annealed and cold-worked pure silver and alloys of silver with 4.5 atomic pct each of Cd, Sn, and Sb are reported. Small amounts of cold work, introduced by stretching pure silver, decrease the internal friction; large amounts of cold work, by wire drawing, cause this decreased internal friction to rise. Results of severol anneoling histories on the room-temperature in-ternal friction indicate a rather complex recovery and recrystallization behavior. A rather system-atic alloy effect is observed for the elements of Period V-B in silver in both the annealed and cold-worked states. DURING recent years internal friction measurements at very small stress levels have been interpreted in terms of structural models and mechanisms occurring within the metal or alloy.These measurements have been made over wide ranges of frequency of vibration and of temperature. While the effects of impurities, alloying, and plastic deformation have been studied by numerous investigators, no investigations of the effect of a series of solutes related by their position in the Periodic Table on a given solvent seem to have been reported. The present paper reports internal friction measurements on silver and on certain silver-base solid solutions to determine the values of room-temperature internal friction associated with varying amounts of plastic deformation and after different annealing

Jan 1, 1957

By Willis T. Burns

I. Introduction.......................................... 703 II. History................................................ 703 III. General Description of Plant......................... 704 IV. AnoDes................................................. 711 V. Cathodes............................................... 714 VI. Electrolyte............................................ 718 VII. Electrolytic Slime..................................... 727 VIII. Power................................................. 728 IX. Operating Details..................................... 732 X. Furnace Refining...................................... 736 XI. Physical Testing oF Products.......................... 739 I. Introduction. These notes are submitted, not as a discussion of the modern practice of electrolytic-copper refining, but as the record of a refinery that was among the pioneers in the field and that is to-day, and has been for 17 years, operating under conditions not to be found in any similar plant in the country. I refer to the current density, which is at least 60 per cent. higher than that regularly employed elsewhere, and to the fact that the anodes treated are the direct product of the converter rather than of the reverberatory furnace. The writer has no knowledge of any other refinery treating anodes of this character. II. History. This refinery, now one of the oldest plants of its kind operating in this country, was built in 1892 by the Boston & Montana Consolidated Copper & Silver Mining CO. to refine the product of its Great Falls reduction works. The estimated capacity of the plant as designed was 65,000 lb. of cathodes per day at a current density of 16 amperes per square foot.

Jan 1, 1914

By Bradley Stoughton, M. Miyake

The importance of magnesium alloys as engineering materials has increased rapidly in the past few years. The most important properties of magnesium alloys are their lightness and strength, which result in their extensive use in aircraft and automobile construction. Recent progress in the metallurgy of magneaium seems to offer hope of the production of the pure metal at a reasonable cost. The use of magnesium would doubtless increase greatly if it could be produced at a cost comparable with that of aluminum. A preliminary survey of the magnesium-base alloys shows that the most promising from a practical standpoint are magnesium-aluminum and magnesium-zinc as binary alloys, and magnesium-zinc-aluminum as ternary alloys. The research reported in this paper is a preliminary study of binary magnesium-aluminum and magnesium-zinc alloys, as an introduction to a series of further investigations. Magnesium-aluminum System The magnesium-aluminum system was first studied by Boudouard,1 who merely determined the liquidus. An accepted constitutional diagram was given by Grube,2 who found a compound A13Mg4 (melting point = 462.7" C.) and two eutectics at 35 per cent. magnesium (451.6° C.) and at 68 per cent. magnesium (440" C.) Between the first eutectic and the compound a solid solution exists. This diagram was checked or supplemented by Pécheux,3 Broniewski,4 Eger,5 Schirmeister,6 Voge17

Jan 1, 1926

Taking advantage of the lessons in administrative organizations which were taught by the war, Director Van H. Manning has put into effect a new form of organization in the Bureau of Mines. The Bureau is divided into two branches, one the investigations branch and the other the operations branch. F. G. Cottrell, who has been chief metallurgist of the Bureau, has been promoted to the position of assistant director and will be in charge of the investigations branch. F. J. Bailey, who has been chief clerk of the Bureau, has been placed in charge of the operations branch with the title of, assistant to the director. All research and technical control will be exercised through the investigations branch, while the non-technical work, administrative duties, and dissemination of the results of the Bureau&apos;s activities will be handled by the operations branch. Under the investigations branch comes the division of mineral technology, in charge of Dr. C. E. Parsons; the division of fuels, under the chief mechanical engineer, 0. P. Hood; the division of mining, under the direction of George S. Rice, the chief mining engineer; the division of petroleum and natural gas, under the direction of J. 0. Lewis, the chief petroleum technologist; and the division of experiment stations, under the direction of D. A. Lyon.

Jan 9, 1919

The Sixty-fifth Congress was a "War Congress." Perhaps nothing else than war work should have been expected of it, but it had time and opportunity to do much more. Engineers have good reason for sorrow over the engineering legislation that died merely because there was no opportunity for a vote. The mineral resources of the public lands of the United States are, except the precious metals, locked away from development. For more than eight years there has been an attempt by both the executive and legislative departments of the nation to secure legislation which, under proper conditions and without detriment to the public interest, will open up these lands for development. After eight years of study, argument, conciliation, and compromise, Congress agreed in conference of the two Houses upon a measure satisfactory to it and to the Executive Department and the final draft was passed by the House of Representatives, but in the Senate it was talked to death by Senator LaFollette of Wisconsin. Some of its proponents plan to, reintroduce the bill identically as agreed to in conference into the 66th Congress, where it is hoped that by reason of its peculiar fate in the 65th Congress it will be regarded in the nature of unfinished business and thus receive early consideration and passage.

Jan 5, 1919

An old philosopher once said, "God grant me the serenity to accept those things I cannot change, the courage to change those which I can, and the wisdom to know the difference." It is time to take stock of how the human race has progressed-whether the trend now points toward greater evils or finer things. It is time that we stop fooling ourselves and put into effect a program of "real" conservation. By this it is not meant that we limit our concept to planting new forests, preserving wild life or preventing soil erosion, but rather taking stock of the expectancy of our resources, expanding human resourcefulness and effecting careful utilization and replacing of, or producing substitutes for, material resources. Man is still dependent upon energy and matter in certain usable forms, despite the fact that energy is inherent in all matter. Until such progress is made that the energy contained in all matter can be controlled, man must continue to utilize the common fuels. Advancement of research in atomic energy has cast a gleam of hope for future use of the tremendous energy contained in the atom. Use of atomic power for industrial pursuits would open up limitless resources of power. This energy, of course, is a two-edged sword, since man&apos;s progress and his means of destruction have always evolved parallel to each other. Thus it is estab-

Jan 1, 1950

The Institute published a collective index of- Volumes I to XXXV inclusive, which has been very extensively purchased and used by the members of the Institute. It enables one to look, up any subject in the first thirty-five volumes and is useful to those who have the Transactions, as well as to those who have not, because it tells what subjects have been treated and enables one to look these matters up in his own library and then afterward either to procure the individual papers from the Institute at the price of $1 each, or to procure Volumes, or to consult the Trans-actions at a nearby library, if such a one is available. It now seems desirable to publish another collective index, and the Editorial Department, upon the authority of the Board of Directors, has prepared an index of Volumes XXXVI to LV inclusive. This will be sold in the Institute&apos;s standard half morocco binding at a price of $5 and in paper covers at a price of $4. It wilt be ready in a few weeks. Those who already have the first index and purchase the second one, and those who purchase both, will have a complete index of the Transactions from Volumes I to LV inclusive. The Institute will be glad to receive advance orders for this index to insure prompt delivery upon publication.

Jan 8, 1917