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By James A. Soles

Concrete is a complex, multicomponent mass whose stability is dependent on three principal variables: quality of the mix, its composition, and environment of the site. The aggregate is only one component, but its constituent minerals may react in unfavorable regimes and, given sufficient time, destroy the concrete. Therefore, besides ensuring that a concrete will meet the strength requirements of a structure, the concrete engineer must be confident that the mortar and aggregates will resist destructive processes. This paper reviews the principal causes and effects of aggregate instability, notes reactions of certain phases, and suggests precautionary measures that can be taken to extend the useful life of concrete structures.

Jan 1, 1984

By Paul A. Beck, A. H. Lutts

IN a previous paper' isothermal softening and X-ray line sharpening data were reported for the annealing at 350°C of single crystals of pure aluminum rolled on the (110) plane in the [112] direction. It was shown that, after rolling to 80 pct reduction in area and careful etching in such a manner as to eliminate extraneous orientations by removing surface material and disturbed areas adjacent to saw cuts, the specimens may be extensively annealed at 350°C without any observable recrys-tallization. At the same temperature, the line broadening caused by cold rolling was found to disappear practically completely after less than 200 sec of annealing. The present work was undertaken in order to study the temperature dependence of line sharpening and of the initial softening with high purity

Jan 1, 1957

By H. Landssberg

Subsidence caused by mining operations has been a matter of interest for the mining engineer for just 111 years, since the Belgian committee for study of subsidence in the city of Liege submitted its first report in 1825. This interest is fairly expressed in the enormous amount of literature that has since appeared on this subject. A bibliography, probably far from being complete, which preceded this study as a preliminary survey, comprises more than 800 titles. In spite of this fact the problem remains today as acute as it has ever been. The questions of as good a recovery as possible of the national resources, the safety of the operations, and the protection of private and public property are the important angles from which to look at the problem. The Problem To systematize an investigation regarding the effects of mine excavations two different aspects have to be dealt with: (1) the subsidence of the immediate roof above the workings, affecting the safety of the workers and the progress and efficiency of the operations; (2) the subsidence of the surface, which is also, from the point of time, the second event. The immense importance of surface subsidence as regards the impairment of surface structures of every kind in a mining area is self-evident. Both effects result from reactions of the strata overlying the excavations and they depend mainly on the extent of the excavations and the structure and geological condition of the strata. It has been stressed repeatedly, in this country principally by G. S. Ricel,† that for the understanding of the phenomenon of subsidence accurate surveys are the most urgent necessity. In the past, however, at least in the normal course of mining operations, these surveys have been very crude. The control of the roof in the mine is left to the observation of the behavior of the timber, warning cracks and sounds in roof and walls and to the general judgment and experience of the worker and his supervisors. In any given case this may or may not be sufficient to prevent fatalities but certainly it does not give any accurate information as to what is happening in roof and strata. On the surface, principally in endangered areas, surveys have been conducted more frequently, but also in this case usually weeks or even

Jan 1, 1936

By Ray Arms

This paper includes a brief classification of dry-cleaning devices, with a theoretical discussion of the principles involved. It outlines the methods of handling dust and screening difficulties at the McComas plant, as well as other plants that are being constructed and other dry-cleaning devices being developed. It describes the American Pneumatic Separator and discusses the sizing required, the effect of moisture in the raw coal, disposition of the middlings, and other aspects of the process. It gives s results of tests on various coals, and results of operation at Raton and McComas. DRY CLEANING, or pneumatic separation, is not, strictly speaking, a recent discovery. Among the archives of the Patent Office may be found many patents dating back as far as 1850 which cover early attempts to separate materials of varying specific gravity or of different shape by means of air. Hundreds of patents covering this art have been issued, which may be roughly classified into four general groups, as follows: 1. Stationary devices with pulsating air currents. The separating surface is usually riffled and air is supplied by bellows or compressors. This group' also includes air jigs, which have been used rather extensively. 2. Stationary devices with continuous air currents. These submitted the material to a continuous current of air, either horizontal or vertical. Chaff is blown from wheat by such a device. 3. Reciprocating or vibrating devices with pulsating air. A small group in which the pulsating air is supplied by bellows and some motion provided in the separating surface to move the stratified material to various discharge points. 4. Reciprocating or vibrating devices with continuous air supply. This is by far the most important group and all recent developments have been along this line. All of the above groups involve the stratification of material by air and include none of the dry methods that use other principles, such as coefficient of friction, magnetism, etc.

Jan 3, 1924

By Ronald J. McGregor, Anton R. Hendriksz

INTRODUCTION The NIMCIX contactor was developed in the late sixties at the National Institute for Metallurgy in South Africa, for the main purpose of extracting uraniuy from relatively low-grade uranium solutions. ' The concept was sufficiently developed by 1974 to permit the operation of a 1500 litre per minute column to treat unclarified urgnium-bearing solution under industrial conditions. The plant operated so successfully that several large-scale units have subsequent18 teen constructed and are operating efficiently. ' Total resin consumption figures as210w as 3 per cent per annum have been reported, and the extraction efficiencies of the installations have been exceptionally good. All the solutions treated have been acidic in nature and in every case have been of such a nature as to significantly depress the maximum uranium loading on the resin beads. The chemical constituents of the leach solution fed to the loading column determines the ease with which the soluble uranium can be absorbed by an ion exchange resin. The concentration of competing ions and various resin foulants define the nature of the continuous ion exchange equipment required for efficient extraction performance. The basic NIMCIX concept is retained in these various alternate designs, but batch or continuous elution methods with fully automated or manual control systems may be selected for the different process solution conditions. BRIEF DESCRIPTION OF THE NIMCIX CONTACTOR The NIMCIX ion exchange column is a multi-stage fluidized bed contactor which is designed to permit a counter-current flow of solution and resin in order to maximize extraction efficiency. The flow o resin is periodic, based on the Cloete and Streat 5 principle of reverse flow. The basic operating cycle can be divided into five periods, as illustrated in Figure 1. For the purposes of describing the cycle, the loading column is considered; how- ever, a similar sequence may be applied to the operation of a NIMCIX continuous elution column. S'I'EP 1: During the forward flow period, Solution flows up through the column and fluidizes the resin contained in each stage. The uranium depleted solution overflows the upper flared-section of the column as the tail solution. Step 2: The flow of solution to the column is temporarily stopped and the resin is allowed to Settle onto the plates in the column. STEP 3: During the reverse flow period, a fixed volume of solution is drained from the column to the transfer vessel. This flow causes resin transfer to occur from stage to stage and also out of the bottom stage. At the end of this period, which expires when the low level switch (LS) is actuated, some of the resin is left in the conical section of the column and the pipe interconnecting the column and the vessel. STEP 4: The cone flush period ensures that all the resin left in the cone of the column and the pipe is transferred to the transfer vessel before forward flow commences. STEP 5: The loaded resin in the transfer vessel, which has been isolated from the column, can either be hydraulically transferred to the top of the elution column or eluted in the vessel before being transferred to the top of the loading column. The major advantages associated with the NIMCIX concept are: (i) Simple method of operation (ii) Contactor can readily be scaled up to large diameters. (iii) Because the resin does not pass through pumps or airlifts, and valves cannot be closed on resin beads at any time, the resin losses are exceptionally low. (iv) Operating costs are low. (v) Relatively few valves in the system. (vi) Stable operation is achieved over a wide range of feed rates and concentrations.

Jan 1, 1980

By Leo H. Glanville

UNTIL 1934, natural ventilation was depended upon in the mine of the Climax Molybdenum Co. at Climax, Colorado. In that year a 7-ft. axial-flow, low-pressure fan was installed as an exhausting unit. In 1936, three more fans of the same kind were installed, all as exhausting units, with a total capacity of 115,000 cu. ft. per min., and since then fans and sprays have been added as required. ATMOSPHERIC CONDITIONS Adverse atmospheric conditions at this elevation of 11,500 ft. account in part for difficulty in maintaining adequate ventilation throughout the mine. Barometric pressures range from 18.99 to 20.01 in. of mercury; the normal average being 19.70 in. Air weight is 0.051 lb. per cu. ft., and humidity is low-about a 30 per cent yearly average. This makes the use of mechanical humidity aids mandatory the year around to prevent excessive dryness of the mine workings and the resultant dust hazard. The yearly temperature range is from minus 24° to 95°F.; typically, in February 1942 the mean low was minus 3.25°F. and the mean high, 21.3°F. In August the mean low was 34.8°F.; the mean high, 64.26°F. Even during the summer month air filtration through the openings of the cave area is 32°F., owing to accumulation of snow in the glory hole and in part to glacial ice, which, combined with a rock temperature of 39°F. on the upper levels (elevation 11,945 ft.) and 42°F. on the main haulage level (elevation 11,490 ft.), makes it difficult to maintain a comfortable working temperature. The one advantage in ventilation of mine workings at the altitude of the Climax mine is that the power required to circulate a given air volume is 32 per cent less than would be required at sea level. PROBLEMS Since 1936 the mine management has studied intensively plans for providing adequate ventilation for the entire mine for its expected life. As the ore breaks into large pieces, much secondary blasting is necessary, therefore there is a considerable amount of smoke, gas and dust, which requires circulation of a large amount of air to remove the contamination. It is undesirable to use haulage drifts and manways as air passages because some would be passageways for contaminated air also, and there would be undesirable high velocities in some drifts. High velocities and large volumes of subfreezing air dry out the passageways through which they pass, and thus increase the amount of dust. Regulating doors in haulage drifts are difficult of upkeep and interfere with production. It was decided as a general principle to distribute fresh air to each working place at low velocities and low pressures and to remove contaminated air as soon as possible with a minimum of travel through working places.

Jan 1, 1943

By S. C. Schaeker, A. W. Schlechten, A. H. Larson

PARRAVANO and Malquori' studied the equilibrium of H2S-Hz with molybdenum and its lowest sulfide which they believed to be MoS2. Mc Cabe' has shown that its composition is actually Mo2S3 and determined its dissociation pressure by means of Knud-sen effusion measurements. Stubbles and Richard- son3 have recently studied the equilibrium of gas mixtures of H2S-HZ with the two-phase solid mixtures of Mo-MozS3 and Mo2S3-MoS2. The latter investigators found that M02s3 deviated slightly from the stoichiometric composition, but they did not determine the homogeneous region of the disulfide phase. Morimoto and Kullerud, studied the Mo-S system by quenching, microscope, and X-ray methods and concluded that the disulfide is stoichiometric. The present investigation was concerned with the measurement of the sulfur vapor pressure variation with composition at 1100°C in the homogeneous region of "MoS2". These measurements were made by reacting: 1) molybdenum powder (99.97 pct Moj with sulfur vapor, and 2) MoS1.g9 (formed by reaction of Mo + H2S) with sulfur vapor in a quartz capsule. Conditions were controlled to form an equilibrated phase within the homogeneous region of the disulfide. The quartz capsule was sealed off initially under a vacuum and the residual gases were gettered by titanium powder contained in one end of the capsule. A mixture of Mo + S or MOS,., + S was in the other end. The section containing the titanium powder was heated for 24 hr at 700°C and then removed by flame sealing. The end of the capsule containing the charge was then heated to 1100°C. The other end of the capsule was maintained at a temperature which would produce the desired sulfur pressure in the capsule (liquid sulfur distilled from the charge mixture was retained in this end). After equilibration, the capsule was removed from the heating assembly and rapidly air-cooled. It is assumed that equality existed between the total sulfur pressures (PT) in the two ends of the capsule and not between the partial pressures of the different molecular species (S, SZ, Three separately controlled heating elements were used to maintain the proper temperature gradient over the length (approximately 12 in.) of the capsule. A thermocouple-Wheelco "Capacitrol" system was used for temperature control of the two end heating elements within 2"C. The center heating element was controlled directly by a " Power -stat". Separate controlling and measuring thermocouples were used for both end heating elements. Pt-Pt(l0 pct Rh) thermocouples were used for 1100°C and Chromel-Alumel thermocouples were used for lower-temperature control and measurement of the assembly. Silver foil was wrapped around the end of the capsule containing the liquid sulfur to insure a constant temperature zone. The thermal gradient over the entire length of the capsule was measured to: 1) ascertain that the length of the constant temperature zone of the liquid-sulfur end and the sulfide end was sufficient, and 2) ascertain that the liquid-sulfur zone was the zone of lowest temperature. The data obtained in this investigation are shown in Fig. 1 and Table I. The total sulfur pressure (PT) and p(S2) were calculated from the data of Braune et UZ.~ The compositions of the equilibrated disul-

Jan 1, 1964

By Anthony F. Lucas

Certain geological indications at Glady's station, four miles south of Beaumont, on the Sabine and East Texas railway (a branch of the Southern Pacific) induced me to undertake a thorough test of that locality by means of a well. I had been making reconnoissances for nearly two years in that part of Texas, before deciding upon this supreme effort. Three previous attempts had been made in the same place: one in 1894 by Messrs. Sharp & Co.; one in 1896 by Mr. J. Looney; and one in 1898 by Messrs. Savage Bros. They had all failed to pass though the immense thickness (500 ft.) of quicksand which underlies the surface soil, clay, etc. At first, I employed the system of boring which I had previously used in the Louisiana salt-deposits.* But I soon found that this method was inadequate, without modification, to deal with the quicksand. Accordingly, I adopted the use of large and heavy castings, and pipes of 12, 10, 8, 6 and 4 in. diameter, successively telescoped one into the other. Boring was begun by Messrs. Hamill Bros., of Corsicana, contractors, about the middle of October, 1900; and on January 10,1901, after many difficulties, a layer of rock containing marine shells was reached, at the depth of 1160 ft. For 150 ft. immediately above, the drill had passed through layers of sandstone and concretions of limestone. At this time there was about 600 ft. of 4-in. pipe, weighing at least 6 tons, in the well; and this, together with the next (6-in.) casing above, was filled with water. When the rock was penetrated the well " blew out," lifting the whole of the 4in. pipe. Mr. Hamill was on the top of the 60-ft. derrick when

Jan 1, 1902

Jan 1, 1969

Jan 1, 1914

By L. A. Roe

The flotation of fine particles less than five microns in diameter and the flotation of liquids from liquids generally requires bubble generation methods different than methods used in dispersed air type machines used in mineral flotation. Conditions in the separatory zone in mineral cells are generally more dynamic as compared to the quiescent conditions often absolutely necessary for the flotation of fine particles and liquids. An example of quiescent flotation with very fine bubbles is the lithium flotation plant which operated at Trona, California for 34 years, until it ceased operations in 1978. A review of the process development and the commercial flotation operations at Trona is given in this paper. The clarification of oil field brines by flotation of the oil from the brine has been used for over twenty-five years. Recent installations related to the Prudhoe Bay oil field and the Alaska pipeline are described.

Jan 1, 1980

By Frank H. Probert

The mining laws relating to winding-ropes in some of the German provinces are very strict, and severe tests have to be periodically made to see that the ropes in use come up to the prescribed standard. A few notes on the method of testing the ropes and the results obtained may be of interest to the members of the Institute. Permission must be given by the Inspector of Mines to put up a winding-plant; and previous to installation a full report made by the manager, clearly setting forth all details of the shaft, the pit-head, engines and appliances appertaining thereto has to be sent to the mining officials. Accompanying each subsequent report, further details, such as the name of the firm supplying the rope, construction, quality of steel, date of installment, weight per meter, length, particulars of the safetycatches, cages, etc., must be given. At least one spare rope must be kept at ever? shaft ready for use in case of emergency. The rope must hang in the shaft, with cage attached, not less than twenty-four hours before it is used for winding; and it must have undergone a severe test in the manner hereafter described. The laws prescribe that when a rope is continually in use it must be tested every three months; but if the rope is only used every few days it must be tested at least every six months, in the presence of the superior officer; and notification of the date of testing has to be sent to the Bergrath two days before the test is made, in order that he can personally superintend the operation if he chooses. Should winding have been stopped for a long time, it is not necessary to test every six months; but before the rope can be used again it must be tested.

Jan 1, 1901

(Under this heading will be published notes sent to the Secretary of the Institute by members or other persons.) The position of converter blower at a side-blow Bessemer steel casting plant is vacant. The State Legislature of Utah has provided for the establishment of a metallurgical research department at the State School of Mines, Salt Lake City. Applications will be received for, the position of head of this laboratory, and further details may be obtained by applying to Prof. Joseph F. Merrill, Director, University of Utah, Salt Lake City. An engineering company owning patents for improvements in steel manufacture which have been adopted at many works in America, desires. to secure the services of a technical iron and steel metallurgist as assistant to its chief metallurgical engineer.

Jan 6, 1913

"Located on Missouri River 16 miles N. E. from Helena, 67 miles from Butte and 18 miles below Canyon Ferry. River drainage area 16,000 sq. miles.DAM: Built in 1907; rebuilt of concrete in 1911. Maximum height 129.3 ft., length over all 720 ft.; elevation of crest 3621; elevation of bridge 3640; normal head 60'; normal tail water elevation 3568.5.SPILLWAY: Length over all 491 ft.; clear opening in 24 sections; 445' flashboards, 14 high to elevation 3635, which is 3.5' above Canyon Ferry normal tail . water elevation.PENSTOCKS: 5 of steel, 12 ft. diam., about 75 ft. long from canal to main turbines, and 3 40-inch diam. from canal to exciters.WHEELS: 5 main pairs, horizontal, center discharge, 48-inch bronze turbines, 225 rev., 4,000 h-p. at 60 ft. head, made by S. Morgan Smith Co., direct coupled to generators, and--3 single, horizontal, 25-inch units, direct coupled to exciters.GENERATORS: 5 W. E. & M. Co. water wheel type, revolving field, 2,800 k-w., 2,400 v., 225 r. p. m., 3 phase, 60 cycle alternators.OPERATION: The plant has a larger water storage than Canyon Ferry and can also use stored water from Canyon Ferry storage. Separate transmission lines 13 miles long connect to lines from Canyon Ferry to Butte, and the Plant operates in parallel with the Canyon Ferry plant."

Jan 1, 1913

The pattern of the coal industry west of the Mississippi River, so far as its history is concerned, is entirely different from that to the east of the "Father of Waters." When the Louisiana Purchase was consummated, one of Jefferson's first thoughts was to ascertain what sort of a country had been purchased, and to that end he sent Lewis and Clark to ascend the Missouri River and to reach the Pacific Ocean if possible, but above all to bring back a report showing the character of the country, its mineral and other resources, inhabitants, etc. This first expedition was supplemented by others to various parts of the vast domain for the same purpose; years later, when transportation routes were necessary to hold and develop the western country, a number of expeditions were sent to explore possible routes for railroads. The records of nearly all of these explorers, as will be shown later, contain references to coal in many localities, the possible value of which was realized but its potential value remained dormant for many years until increasing population and methods of transport made markets available. Missouri was the first state west of the Mississippi in which coal was produced and the names of a number of places show that the French were familiar with the coal deposits there. Lewis and Clark, soon after they left St. Louis, passed "a remarkable Coal Hill on the Larboard Side, called by the French Carbonere, this hill appeares to Contain great quantity of Coal."1 This hill was about seven miles below St. Charles. No other outcrops were seen by them until they had passed the present limits of the state. The Louisiana Gazette of April 9, 1805 contained an article on "The Missouri," author not stated, which said, "the short stay we have generally made among the savage nations has prevented us from making those researches, which would have supplied us with a more extensive information respecting the various mines found on the borders of the Missouri; we know with certainty only those of iron, lead and coal." In 1806 Pike passed through Missouri on his tour to Mexico. On August 17th, along the Osage River he remarked, "here the river-bank is

Jan 1, 1942

Organization Place - Date 1918 American Iron and Steel Institute New York, N. Y. May American Water Works Association :.. St. Paul, Minn. May 20-25 American Institute of Chemical Engineers Berlin, N. H.. June 19-22 American Concrete Institute Atlantic City, N. J. June 24-26 American Society for Testing Materials Atlantic City, N. J. June 25-28 New York Electrical Society New York, N. Y. June National Association of Stationary Engineers Cincinnati, 0. Sept. 9-13 National Exposition of Chemical Industries New York, N.Y.. Sept.23-28 American Chemical Society Cleveland, 0. Sept. National Petroleum Association Atlantic' City, N. J. Sept.

Jan 5, 1918

Jan 2, 1966

By J. C. Todd

The volume of air needed to move the combustion wave through each acre-foot of the reservoir is a very important quantity for engineering economic analyses. A new method, which involves backflowing the injection well, has been developed for determining the air requirement .for the forward combustion thermal pilot in the Delaware-Childers field. The method depends on measurement of the total volume of air injected and measurement of the pore volume in the zone swept out by the combustion front. The basic premise of the method is that the pore volume of the swept zone contains air, while the formation around this zone contains flue gas, oil and water. The pore volume of the swept zone is determined by blowing down the pilot section of the formation through the injection well after the pilot is shut down. Oxygen balance is used to differentiate between air from the swept zone and flue gas from the surrounding formation. Data indicate that air'is produced from the swept zone by relatively efficient miscible displacement by the flue gas. The pore volume occupied by the air in the swept zone is determined by simple PVT relationships. The average temperature of the swept zone is calculated by heat balance from the total amount of heat generated during the pilot and losses to the surrounding formation. The new method was applied successfully at the conclusion of the pilot in the Delaware-Childers field; the air required for the reservoir conditions involved was calculated to be 19.2 MMscf/acre-ft of reservoir swept. INTRODUCTION One of the most important pieces of information to be found from a forward combustion pilot is the air requirement; that is, the volume of air needed to move the combustion wave through each acre-foot of the reservoir. Compression costs per barrel of oil recovered, which are a direct function of the air requirement, are a large portion of the expenses incurred in the thermal recovery process. Thus, the profitability of thermal recovery depends largely on the air requirement, which is a measure of the amount of fuel deposited and burned in the thermal recovery process. Several attempts have been made to correlate crude oil properties with fuel deposition and, hence, air requirement.l*2 Other attempts have been made by our laboratory to find the air requirement by material balance, gravity survey, pressure transient analysis,3 magnetic survey and the poten-tiometric model. Better methods are needed to predict more accurately the economics of fieldwide application of the process. Another method of finding the air requirement consists of operating a pilot thermal project for several years. This is followed by an extensive coring program to define the volume swept by the combustion wave. The air requirement is found from the total injected air divided by the volume of the swept region found from the coring operation. This method is costly; an adequate coring program usually costs several hundred thousand dollars. A thermal pilot was operated in a watered-out portion of the Delaware-Childers field, Bartlesville sand, from Nov., 1960, until May 3, 1965. One of the primary purposes of this pilot operation was to determine the air requirement for economic calculations which determine the advisability of expanding the project to the entire 128,000 acre-ft field. Barnes4 has described the result of this pilot operation,, including calculation of the air requirement from limited coring data. The value obtained, as calculated, was 15.8 MMscf/acre-ft. One purpose of this report is to describe a new method of finding the air requirement from a thermal pilot operation. A second purpose is to describe the application of this method to the Delaware-Childers thermal pilot. THEORY AND DESCRIPTION OF THE METHOD The combustion zone in the forward combustion process is propagated from injection w producing

Jan 1, 1970

By E. T. Turkdogan

Jan 1, 1962

By T. K. Matthews

Minerals are mined as a one-time crop, and the processing of one ton of ore results in there being one ton less to be recovered from the deposit. Although some minerals occur in greater abundance than others, they are to a greater or lesser degree exhaustible. Depletion Allowances One of the distinctive features of the mineral industries is the allowance for depletion. The depletion allowance is a much maligned and misunderstood principal of our tax structure. Although imperfect in design, it has nevertheless served as a constructive incentive for the development and expansion of the minerals industry.

Jan 1, 1969