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By Charles B. Dudley

In view of various papers and discussion.;, at recent meetings of the Institute, upon testing, methods of testing, inspectors, inspection and specifications, it has occurred to me that my experience of some fifteen years, in the making and enforcement of specifications, in connection with the Motive Power Department of the Pennsylvania Railroad, might give some value to the few suggestions offered in this paper. There is friction, not to say antagonism, between the producers and the consumers of structural materials. On the one hand, the producers complain of the severity of inspection, or the lack of knowledge and want of good judgment on the part of inspectors, and, indeed, have gone so far as to suggest the abolition of the whole scheme of inspecting and testing materials. On the other hand, the consumers are, apparently, more and more relying on specifications

Jan 1, 1893

By J. H. Wernick

IN a study of the rate of decomposition of ½ -in. cubes of limestone, dolomitic limestone, and dolomite in a sweeping nitrogen atmosphere, Joseph, Beatty, and Bitsianesl found that the zone of calcination advanced at substantially a constant rate at a given temperature. The purpose of this paper is to show that their data indicate at least two processes occurring when the above carbonates decompose. It is suggested that there are two processes occurring temperature range and the other the limiting process over another temperature range. The data of Joseph and co-workers have been extended by use of the Arrhenius equation, Eq. 1, a relation beween the velocity constant k of a reaction and the absolute temperature T.

Jan 7, 1954

By W. T. Turrall, M. J. Cook

A discussion of modern developments in beneficiation of fine sizes of anthracite, this paper includes a description of the plant flowsheet, an analysis of operating results, and a summary of fundamentals of mineral separation relative to plant operation. DURING the past several years Lehigh Naviga-tion Coal Co. has installed equipment at Tamaqua and Lansford collieries for cleaning and sizing No. 4 buckwheat —3/32 + 3/64 in. and for recovering and cleaning flotation coal —20 + 200 mesh at Tamaqua colliery. Papers describing some of these installations have been presented to AIME. At Coaldale colliery, however, methods used to clean fine coal were inadequate and inefficient. Management decided upon a thorough investigation of all existing processes before building a plant to treat the combined three sizes mentioned. Investigation, carried out on company property and at other plants, entailed a study of hydrotators, hydroclassifiers, tables, spirals, flotation machines, methods of screening, and methods of dewatering. On the basis of this investigation a flowsheet was designed which necessarily excluded many processes in use, and the writers wish to emphasize that no criticism is implied by omission of processes or machines. A determining factor in selection of many machines was the policy of standardizing equipment wherever possible. Flowsheet and Operational Data The first principle to be considered in designing of any plant is efficiency of cleaning as related to laws of classification. Beneficiation of coal may be described as separation of two materials having different specific gravities. Although there is an inherent ash content even in the purest coal which slightly affects its specific gravity, it is recognized that many particles are true middlings. The percentage of these particles allowable in the final product depends upon the ultimate ash, or specifications of the consumer. Richards in his study of free settling and hindered settling classification' determined that particles of equal size and different specific gravities had unequal settling velocities. He also determined a definite size relationship for equal settling velocities with free settling and hindered settling conditions. Considering the design of machines used to clean No. 4 and No. 5 buckwheat, it may be assumed that both free settling and hindered settling conditions exist and that ratio of size for practical operations is between the established values. The essential factor is that the more efficiently and closely sized the feed is maintained, the more nearly perfect the resulting separation. Flowsheet design was governed primarily by factors related to the 1200 to 1500 tons per hr feed to the main plant. It should be stressed that because of the many sources of supply from mine and stripping, the physical characteristics of this feed varied considerably. The most significant influence was varying percentage of fines, necessitating that all machines be capable of operating under maximum peak load during periods of surge. Since cleaning practice is a wet process, about 9000 gal per min containing 14 to 15 pct solids, or 350 tons per hr, must be treated. This slurry contained all the fines, or —3/32 in., but also percentages of oversize, up to 1 % in., dependent on spills or breaks in screen jackets, a not uncommon occurrence in preparation plant practice. The flowsheet developed is shown in Fig. 1. Circled numbers represent points of sampling. Table I gives operational data including size, ash by size, composite ash, rate of flow in gallons per minute, percent solids dry weight, and average tons of solids per hour. It should be noted that these results are subject to human error in sampling practice. Detailed information reported is a representative evaluation of plant operation.

Jan 1, 1954

By Robert D. Gunn, John E. Boysen, Dennis D. Fischer

The second underground coal gasification experiment conducted by ERDA's Laramie Energy Research Center at a site near Hanna, Wyo., was completed on Jul. 30, 1976. During the experiment production reached 0.32 blm3/d (12 M cu ft/d) of 6.9 w/m3 gas (175 Btu per cu ft). Approximately 6100 tonnes (6700 tons) of coal were gasified during the experiment. Energy return ratios of 4.5 to 5.3, coal gas thermal efficiencies of 76 to 89%, and overall process efficiencies of 65 to 74% were achieved during the second Hanna experiment. This paper describes the experiment and the results obtained with emphasis given to the determination of the energy recovered relative to energy consumed in conducting the test. Data from this determination are compared with previously published data from the first test conducted at Hanna during 1973-74.

Jan 1, 1978

The data about production in this county are exceedingly meager, and there are few reliable data about shipments. It is probable that consid¬erable amounts of coal from here moved north to Erie by both the Beaver and Erie. Canal and the Erie and Pittsburgh Railroad, and if so, they are included with Mercer County. The data in the early state reports are very inaccurate and are always much too low. Much of this coal was used in local furnaces and iron plants and not handled by railroads. There was some production in this county on the line of the Pittsburgh, Fort Wayne and Chicago Railroad, of which no record can be found. The estimated production is based on the number of mines reported as operating in the county at various dates and their probable output, as suggested occasionally in county histories. It is believed that these figures are below, rather than above, the actual figures, which can now never be obtained.

Jan 1, 1942

Jan 1, 1918

Jan 1, 1920

Jan 1, 1925

By Edward V. D’Invilliers

In connection with some recent professional work in the coalfields of Western Pennsylvania, with special reference to results of coking operations, I was asked to compile a statement giving the estimated cost of mining coal and manufacturing coke at two hypothetical plants of 500 ovens each, giving the relative yield of coal in coke at each plant; and, upon the average number of working days in each of the past five years, from 1899 to 1903, together with average selling price of coke at the ovens, to prepare an estimate of the relative commercial returns in each district. What seemed at first sight to be a comparatively simple proposition, involving only the ordinary elements of mining and coking costs, became complicated by the lack of standard published records of mining costs and sales, which would be applicable to the subject at issue. Upon searching through the usual channels of Government publicatious and the files of our technical societies and mining periodicals, I was surprised to note the absence of fundamental factors that would approximately meet the case in point. The very elaborate and interesting statistics annually published by the National Government' do not supply the required data for the following reasons:—1. Being reported by arbitrary districts, the average values are too general to be applied to special fields. 2. The value of coal charged to the ovens is apparently based upon the regional average value of the coal if sold in the market, and not upon the cost of production. 3. Some plants only use the slack (a by-

Jan 1, 1905

By H. O. Hofman

Jan 1, 1896

"The pumping of the underground water of the Butte mines is largely done from two central plants of the Anaconda Copper Mining Co. The mines of one part of the mining district are served by a modern and mechanically efficient underground plant at the High Ore mine, and the remaining part by a similar one at the Leonard mine. Properties not affiliated with the A. C. M. Co. have separate pumping plants, although in several instances that company handles the water of outside companies, under which arrangement costly single plants are dispensed with. An extensive system of underground crosscuts and drifts connects these mines to both the main pumping plants, so that either may receive the water from all the mines in case there should be a failure in the other to perform its designed service.Quintuple) vertical electric pumps, 7 inches by 12 inches each, of a capacity of 600 gals. per minute under a head of 1,203 feet, are installed at both the plants. Each pump is direct connected to two 150 h-p. motors using 2,300 volts, the motors being on top of the pumps.At the High Ore plant the power cable of 400,000 c. m. is placed in a nearby shaft, the cable at present being hung from the surface to the 2,200 level. From this cable feeders of 300,000 c. m. are laid in connecting crosscuts to the pumping station at the High Ore shaft.The Leonard motors use 440 volts. The practice of building the pumps with the motors on top requires stations with high roofs, but permits the operation of the pumps if they should be submerged by an unusual flow of water."

Jan 1, 1913

By Charles Locke

IT will soon become apparent that the Conference Committee's choice of the title for this presentation is a fortunate one for the speaker; since if it had read "Review of Known Facts Controlling Slag Volume" he would best step down right now. There is a dearth of facts in a quantitative sense on this subject, especially in regard to the effects of slag volume on the acid electric practice for steelmaking, as borne out by a library search involving some 175 references from 1915 to date. Even the opinions in these references on any phase of slag volume are meager. This, then, leads to a report that is candidly based on private observations, on readings and on conjectures gleaned from gossiping with fellow practitioners. Perhaps the subsequent papers, which, as I understand it, are substantiated by actual measurements, of slag volume versus specific contributing factors, will be able to acclaim or disclaim my remarks.

Jan 1, 1947

By Oliver Bowles

ALTHOUGH Oliver Bowles retired as chief of the nonmetal economics division of the Bureau of Mines last year, that retirement has not lessened his active interest in the field of nonmetallic minerals, in writing, nor in his hobby, cultivation of African violets. Excellent co-ordination of the timing of a professional meeting and a flower show permitted him on at least one occasion to attend technical sessions and take in the African violet exhibition which happily arrived simultaneously in one city. Dr. Bowles celebrated his seventieth birthday on Jan. 10, 1947, and

Jan 1, 1948

By L. J. Dijkstra, R. J. Sladek

IN earlier work the effect of manganese on the general behavior of nitrogen in iron was the subject of a careful examination by Fast.' Part of the investigation was made, in collaboration with one of the present authors (L.J.D.), by using the internal friction method. This technique, which has been described elsewhere,' showed some significant changes in the properties of Fe-N alloys by the addition of a small amount of manganese namely: 1—Under standard conditions the maximum of the nitrogen peak in pure iron appears around 20 °C and the half width is about 27 °C. By addition of 0.5 atomic pct Mn a general broadening of the internal friction peak occurs. The half width is increased by about 9°C. Moreover, a shift of the maximum of about 5°C toward a higher temperature takes place, Fig. 2. 2—The precipitation of nitrogen from the supersaturated solution, measured, e.g., at 200 °C, was inhibited by the addition of the amount of manganese given in effect 1. The broadening of the nitrogen peak was confirmed in more recent work3 on samples which were prepared from Westinghouse Puron iron. The effect of manganese on the rate of precipitation, however, was much less striking than in the earlier work' based on Philips high purity iron. Theory To explain the first change in properties just referred to, effect 1, the following two assumptions were made:' First, every manganese atom in sub-stitutional solid solution creates around it six interstices located between an iron and a manganese atom, as is evident from Fig. 1. These interstices, conveniently called Fe-Mn interstices, have for nitrogen a free energy level which is AG* lower than the normal Fe-Fe interstices between two iron atoms. For such low concentrations of manganese as 0.5 atomic pct, the possibility that two manganese atoms will be nearest neighbors can be disregarded. Second, it is assumed that in addition to the normal relaxation time TFe at least one new relaxation time, Mn, Fe, enters in the phenomena which is associated with the elementary diffusion jumps between a Fe-Mn interstice and an adjacent Fe-Fe interstice. Fig. 1 gives schematically the free energy for a nitrogen atom as a function of its position along the line ABC. A tentative analysis of the nitrogen peak in a 0.5 pct Fe-Mn alloy based on these assumptions has been made in Fig. 2. The dotted curve with a maximum at 22°C is caused by jumps between Fe-Fe interstices, the dotted curve with maximum at 32°C by jumps between an Fe-Mn and an Fe-Fe interstice. The two effects added together give the dash-dot internal friction curve for the alloy. In the following these two components will be referred to as the normal peak at 22°C and the abnormal one. (The small secondary peak at

Jan 1, 1954

By Dr. Egleston

While I thoroughly appreciate the United States testing-machine at the Watertown Arsenal, and regard it as the most accurate testing-machine that has yet been built, I wish that I could say that it is complete in all respects. I not only fully appreciate it, but I have given up advising thesending of material to be tested anywhere else. It is five or six times more expensive to use this machine than any of the others, but the results which are obtained from it are, I think, perfectly reliable, and of such a character that the tests are all comparable with each other. It has proved, beyond a doubt, that the system of testing specimens of' diminished area, and then calculating that the metal examined will be as many times stronger as its area is greater, is an absolutely vicious one. I am quite prepared to say, that, either from their limited size or faulty construction, most of

Jan 1, 1882

By D. S. Pye, J. P. Gallus

Successful hydraulic pressure treatment of oil and gas wells that have long producing intervals, multiple pay zones, fluid thief zones, or natural or induced fractures has long been a serious problem plaguing the petroleum industry. High fluid-injection rates, straddle packers, ball sealers, and either liquid or solid additives to the treating fluids are being used to cope with this difficult and costly problem.l-6 The use of ball sealers and straddle packers is limited, in practice, to wells that have been completed with perforated cemented casings or liners. Well stimulation with ball sealers and straddle packers is usually successful as long as the cement remains competent. The other techniques of diverting are used with all types of completions. However, there are two significant disadvantages of the high rate method: excessive horsepower requirements, and the need of large treating-fluid volume. Consequently, most well stimulation techniques that involve diverting depend upon ball sealers or granular materials. Liquid diverting agents, and some of the solid ones in use today, frequently will cause formation damage. On the other hand, the most popular particulate diverting agents often are so soluble in the treating fluid that they become largely ineffective; their particle size is severely reduced as they dissolve while being transported through thousands of feet of pipe to the formation face down hole. In our attempts to deal with the shortcomings of these diverting agents, we experimented with a large variety of potentially suitable deformable materials the solubility of which could be controlled. Following are the criteria for the diverting agent sought: 1. The material must be effective in reducing fluid loss to thief zones, including existing fractures and very high permeability layers in the formation to be pressure treated. 2. The material must have enough strength to bridge under the treating pressure. 3. The material must be insoluble or slowly soluble in the treating fluids so that the particles retain sufficient size to be effective after they reach the formation face. 4. The material must be completely soluble in the produced oil or condensate liquid so that it can be removed readily; it must not cause formation damage. A number of products consisting of various polymers blended with waxes and other solid hydrocarbons were examined. All these materials satisfied the criteria for a diverting agent and also exhibited some degree of plastic deformability. On the basis of initial tests of strength and hardness, several blends of wax and polymer were selected for extensive testing in the laboratory and the field. These compounds have congealing temperatures ranging from 140 to 190F; they are insoluble in water and soluble in oil. They conformed, therefore, to the criteria specified for a theoretically superior diverting agent. Laboratory and field tests were conducted using these wax-polymer materials to demonstrate that the use of a deformable diverting agent can significantly improve fluid diverting performance. Data in this

Jan 1, 1970

By J. Weertman

An explanation is advanced for the recent results of Barrett and Sherby on the high-temperature creep of fee metals. Their measurements indicate that metals with a low stacking fault energy creep at a much slower rate than metals with a high stacking fault energy. The explanation is based on the assumption that the rate of core diffusion is much smaller in partial dislocations than in perfect dislocations. An experiment is suggested to test this assumption. The explanation also requires that the jog density is small on widely split dislocations. SHERBY and Barrett1,2 recently established an important result in the field of high-temperature steady-state creep. They have shown that fee metals whose dislocations split into partial dislocations separated by a wide stacking-fault ribbon creep at a much slower rate than fee metals whose dislocations are not split appreciably. The creep rates in the two cases may differ by a factor as high as 6000. (For the purpose of comparison, the test temperature of each metal was chosen so that its rate of self-diffusion was equal to a standard value. Similarly the stress levels were such that the ratio of the stress to an appropriate elastic modulus was the same for each metal. In all cases the stresses were sufficiently low that the steady-state creep rate was proportional to the stress raised to a power.) It is the purpose of the present paper to attempt an explanation of this interesting and significant result of Sherby and Barrett. The activation energies of high-temperature creep of the metals tested by Sherby and Barrett (aluminum, nickel, copper, and silver) were equal to their self-diffusion activation energies. Hence it appears reasonable to assume that this type of creep is controlled by a dislocation-climb process, which in turn is controlled by the diffusion of vacancies to or from dislocation lines. (It will be assumed that the diffusion of interstitial atoms is unimportant in the climb process. The analysis could be repeated for the case in which interstitial atoms are important.) In prior papers374 I have treated dislocation climb by using the assumptions that core diffusion is extremely fast down a dislocation and that a dislocation always maintains an appropriate vacancy concentration in its immediate vicinity. In this

Jan 1, 1965

By Frank A. Crossley

The work described has one serious shortcoming: grain size was not monitored during heat up to the temperature (1675°F) of isothermal anneal. The chief obstacles to p grain growth in titanium a-ß structures are the a grains. Heating a structure such as that shown in Fig. 1 to a temperature close to ß transus causes dissolution of a grains in order to adjust the a/ß ratio, compare Figs. 1 and 2. During this process there is a concomitant growth of the ß grains—otherwise ß grains would have to be nucleated in order to adjust the a/ß ratio. When the annealing temperature is reached the a/ß ratio stabilizes and this initial phase of ß grain growth ceases. After an incubation period growth resumes as described. Some 0 grain boundaries can be clearly seen in Fig. 1. (Skilled metallography commonly produces photomicrographs which show more structural detail than direct observation.) These boundaries suggest that the average ß grain size is approximately 0.002

Jan 1, 1970

By Stephen C. Blair

Laboratory permeability measurements at elevated pressure and at temperatures ranging from 20º to 150°C have been conducted on samples of Ironton-Galesville sandstone. The purpose of this testing was to identify and characterize important physicochemical processes occurring in association with the injection and withdrawal of heated ground water at the U.S. Department of Energy's Aquifer Thermal Energy Storage (ATES) field site in St. Paul, Minnesota. Results indicate that permeability decreased significantly as temperature was increased and that dissolution of the dolomite and silicate cementing agents and accompanying changes in mechanical properties may occur in the heat storage aquifer at St. Paul. Further, loss of permeability with temperature in laboratory samples may be caused by the change in the mechanical structure of the sample. Tests at ambient temperature to evaluate the effect of particle migration under conditions of reversed flow indicate that this process will not significantly impair formation permeability at the St. Paul site.

Jan 1, 1984