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By I. Milton LeBaron

Operation of the phosphate flotation plant at the Peace valley mine of the International Minerals and Chemical Corporation, Florida, began in the summer of 1942. Since that time several changes have been made in the flowsheet, with resultant increases in metallurgical results. Three flowsheets, together with the comparative plant results, are given in this paper, together with a discussion of the desliming circuit used for preliminary washing of the flotation feed. Fig. I lists the essential units in the original flowsheet at the Peace Valley plant. The figures for tonnage and grade are average for a period of two months. Mineral Separation Airflow cells are used for both the fatty acid and the amine float. Three immediate difficulties presented themselves in the use of this flow sheet: I. Floating a maximum amount of phosphate in the rougher section to give good recovery sent a low-grade concentrate to the silica float, resulting in high costs for amine reagent in that section.

Jan 1, 1947

By I. Milton LeBaron

Operation of the phosphate flotation plant at the Peace valley mine of the International Minerals and Chemical Corporation, Florida, began in the summer of 1942. Since that time several changes have been made in the flowsheet, with resultant increases in metallurgical results. Three flowsheets, together with the comparative plant results, are given in this paper, together with a discussion of the desliming circuit used for preliminary washing of the flotation feed. Fig. I lists the essential units in the original flowsheet at the Peace Valley plant. The figures for tonnage and grade are average for a period of two months. Mineral Separation Airflow cells are used for both the fatty acid and the amine float. Three immediate difficulties presented themselves in the use of this flow sheet: I. Floating a maximum amount of phosphate in the rougher section to give good recovery sent a low-grade concentrate to the silica float, resulting in high costs for amine reagent in that section.

Jan 1, 1947

By Frederick W. DeVries

Since we first agreed to present this talk we have learned that some of you may have been covering ground we intend to discuss: Bob Schechter, Daryl Tweeton, Don Seidel, Herb Burgman; however, the ideas were original when we began, "novel" as in the title of the talk, and whether our results are news or merely corroborative, we feel they point a direction that could be valuable to all. We worked with many of you in the past on using hydrogen peroxide in in-situ uranium leaching. Our talk today is not directly related to peroxide; it is, I hope, illustrative of Du Pont&apos;s interest in providing service to this industry in any way we can. The scouting work we are presenting was stimulated by field inputs: First, ammonium carbonate leaches cause restoration problems, primarily because ammonium ions exchange on clays with calcium. Second, sodium carbonate solutions, especially in South Texas deposits, can cause intolerable swelling of clays. From discussions with Dr. van Olphen, who wrote the book on clay chemistry, we inferred by comparison of the radii of the hydrated ions of the elements in these clay systems, that since potassium had about the same radius as ammonium, and sodium was much larger, potassium occupied a unique position to solve both problems. We have shown: FIGURE 1 Potassium bicarbonate systems leach uranium without loss of permeability found with sodium Potassium salts are very effective in restoring ammonia-leached sites Before reviewing the details of our work, which was performed by Hazen Research, Inc., I should like to stress its scouting nature. We are trying to assist the in-situ industry by pointing out new, potentially important directions. But, as with our previous work on sodium silicate to restore permeability, we feel the development phases can generally best be carried out in cooperative programs with companies directly involved with operations. DISCUSSION Test Parameters Now for the details: Our leaching tests were designed to note pressure-drop changes across the ore sample as the uranium was leached. Figure 2 shows the apparatus. The [ ] packed length was 20.5 inches (52 cm) with fifteen hundred grams of ore in the two-inch (5 cm)-diameter bed. Pressure drop was measured by manometer and feed rates were maintained constant with a tubing pump. The samples, from a South Texas leach site, were sealed in "Zip Loc" bags, frozen with "dry ice", crushed (still frozen) through six mesh, and blended before placement into the columns. The ores analyzed as shown here: FIGURE 3 Ore Analyses [Sample A Sample B U308 015% 0122% Mo 0004% 0086% Se0012% <0001% Fe3,078%076% Fee- 098% 044%]

Jan 1, 1979

By Frank M. Brewster

The handling of congealing oils and paraffin is a serious problem in the Appalachian fields, particularly because the small amount of oil produced per well makes the removing of paraffin a very costly operation per barrel. Few operators realize or have any means of knowing just how much production is lost on account of paraffin depositing over the face of the sand and plugging the pores of the sand; but where paraffin has been removed the production increases indicate that this loss has been considerable. Many operators believe that paraffining is confined to the tubing and pumping equipment, but it is evident that the most serious damage occurs on the face of the sand and a short distance back in the pores. This paper is an attempt to disseminate information on methods and processes in use in the Eastern fields for combatting losses of production and operating difficulties caused by deposition of paraffin in the pores, on the walls, on the tubing and on other pumping equipment. Mills1 covers this subject so thoroughly that excerpts, abstracts and quotations from his work have been used freely in this paper. Nature oF Paraffin Mills states: "The so-called paraffin that collects in oil wells, and in the pores of the producing sands immediately around the wells, is generally made up of amorphous wax or uncracked paraffin, asphalt, or other gummy hydrocarbons mixed with more or less water, oil and inorganic silt. Some of the samples of this paraffin collected from oil wells in different fields and examined by the Bureau of Mines contains as much as 20 per cent. by weight of water and inorganic silt, whereas other samples are composed entirely of waxy hydrocarbons and oil. The inorganic silt accompanying this &apos;paraffin&apos; is mostly fine sand, clayey materials, common salt and finely disseminated precipitates of calcium and magnesium carbonates. Sulfates of calcium, barium and strontium are less common constituents of paraffin.

Jan 1, 1928

By W. J. Shearer

A COMPARISON of statistics relating to coal min-ing in Great Britain and the United States leads one to suspect widely differing conditions and practice. A brief review of some of the conditions may enable American mining men to appreciate more fully the difficulties with which British engineers are faced, and to some extent explain why American, coal can be sold f.o.b. mine at the present time at about 50 to 60 per cent of the cost of British coal at the mine, and why British man-shift outputs fall far below American at present being less than 30 per cent. Bulman gives the average depth of 6-ft. seams. in Britain at 1350 ft., and of 2-ft. seams at 517 ft. George S. Rice states that 90 per cent of American coal &apos;is taken from less than 600 ft. Much English coal is taken below 2000 ft. and some below 3000 ft. The total influence of depth on cost is not always evident. Room work as known in America becomes less advisable with increasing depth, as pillars crush badly if left -for any length of time. A limited amount of bord and pillar work, taking very small amounts of coal in the first working, takes the place of room work, with rapid working of the pillars as soon as the panels are broken. Ventilation difficulties increase tremendously with depth and thinning coal. In America the chief use of air underground is to dilute gas. In Britain it serves a dual purpose, in many cases the amount of air cir-culated being far in excess of the quantity necessary to dilute gas to reasonable proportions. At great .depths rock temperatures exceed-95 deg. F., and great volumes of air are necessary for rock cooling. At these high temperatures humidity becomes an important factor. At present a great deal of research is under way to find methods of overcoming the troubles experienced with high temperature and humidity in deep mines.

Jan 8, 1928

By Joseph Richards

THERE are two essentially different types of case-hardening processes; that using a dry mixture in which the object to be case-hardened is packed and kept for the necessary time at the necessary temperature, and the "liquid" process, employing a bath of fused, salts into which the object- is immersed and which by immediate contact case-hardens the surface of the article. The Shimer process belongs to the second class, and was a war emergency invention. Of the liquid melts used as baths, the most effective and most fre¬quently used are melted potassium cyanide and melted sodium cyanide. These may be used either pure, or mixed with salts that reduce the melting point and the percentage of cyanide present. The use of these baths since 1914 has met many commercial difficulties because of the high price and frequent commercial scarcity of the cyanide salts; at present sodium cyanide has practically entirely displaced potassium cyanide. Another trouble is the danger to the workmen handling the cyanide salts, which are extremely poisonous, and the annoying and poisonous vapors or gases given off in the workshop, unless an effective system of hoods and ventilation is provided, so as to prevent the gases from the baths mixing with the air of the room. Porter W. Shimer, of Easton, Pa., has invented a substitute for the bath of melted cyanides which case-hardens with equal or greater facility and effectiveness, gives off no poisonous vapors, and costs for chemicals materially less than the cyanide costs in the previously used baths. The process has been in use over a year in a large American works and the following statement embodies the results of practical experience in the use and operation of the process. The Shinier liquid or melted bath consists of a mixture of easily fusible salts that do not possess case-hardening properties, into which is immersed fresh calcium cyanamide, which imparts to the bath case-hardening properties. The composition of the non-case-hardening-,salts appears rather immaterial. Good results have been obtained by using a mixture of sodium chloride, calcium chloride, and barium chloride in

Jan 2, 1919

By W. H. Corbould

The township of Cloncurry is situated in the northwestern part of Queensland, about latitude S. 20" 42&apos; 53" and longitude E. 140" 30&apos; 25". Townsville is the port through which all the trade passes and is about 470 miles east-northeast of Cloncurry township. The Cloncurry copper district covers an area about 200 miles long by 40 miles wide. Unfortunately the mines are very scattered over this area, there being no large groups of mines. Mount Elliott mine is situated about 70 miles south from the township of Cloncurry, and Mount Oxide mine about 150 miles north of Cloncurry. The district has been known for the last 35 years, and in the early stages a large amount of capital was expended with little to show for it; but within the last four years the railway has been extended from Townsville to Mount Elliott and about 40 miles north of Cloncurry, which has made possible the treatment of the ores of the mines on this extension. The Mount Elliott company within the last few years has smelted and converted on its mine 169,688 tons of ore for 20,554 tons of blister copper, containing 20,377 tons of copper, 35,642 oz. of gold and 28,841 oz. of silver, at a cost of about 233 per ton of blister copper, f.o.b. Townsville. This cost included all development, wages, salaries, general management, office, agency, legal expenses, freight, etc. The gold and silver contents would practically pay for freight to Europe, refining, realization charges, etc. The costs of supplies are as follows: Firewood, 15s., coke, 75s., mine timber, 54s., and coal, 60s. per long ton; explosives: dynamite and gelignite, 50s., and blasting gelatine, 65s. 6d. per case, Mount Elliott Mine The pay shoot of the orebody outcrops at the surface for about 200 ft., and lies between two slate walls about 40 ft. apart., having a general

Jan 1, 1915

By A. B. Kinzel

MUCH work has been done recently in an attempt to analyze the physicochemical mechanism involved in the production of steel by the open-hearth process. . This has resulted in reducing the process to a series of interrelated phenomena obeying the usual laws of mass action and diffusion. Of these, the reaction of the iron oxide and carbon in the molten steel is of most interest from a technical point of view as it con-stitutes the main action in the usual steelmaking processes. A. L. Feild1 has formulated a basic differential equation expressing the open-hearth reactions and Hefty has done considerable experimental work on the determination of a number of constants involved in the basic open-hearth reaction. In considering the application of the law of mass action. to the reaction FeO +C ?? CO +Fe, the iron will be taken as constant, as is the case in the open hearth and the carbon monoxide pressure will be assumed&apos; constant at one atmosphere. From this xy = m at equilibrium, where x is the percentage weight of carbon, y percentage weight of iron oxide and m the weight-concentration equilibrium constant. While it is customary for physical chemists to express equilibrium constants in terms of molar concentrations, the constant is here expressed as the product of the percentage-weight concentrations for ease of comparison with the constants quoted by Herty and by Feild, and for more ready applicability to the open-hearth reactions. Herty and his associates have attempted to calculate the value of this constant from data on open-hearth heats. So many variables affect these results that an adequate calculation presents very great difficulties. A value of 4 X 10-2 was first arrived at, but this was later changed to 1.6 X 10-2. Feild, in order to illustrate the operation of the differential equation of the open hearth, has assumed a value considerably lower than Herty&apos;s, namely, 1.0 X 10-2, the largest value consistent with certain theoretical

Jan 1, 1929

EARLY this year the Board of Directors announced that, through the generous gift of past-president W. L. Saunders, a gold medal to be awarded for distinguished achievement in mining had been estab-lished. At the December meeting of the Board the medal committee reported that it recommended that the first medal be awarded to David William Brunton for "development and exposition of the principles and prac-tice of ore sampling; for systematic daily mapping of mine geology; for the Brunton mining compass; and for engineering achievements in connection with great tunnels." The formal presentation of the medal will be at the din-ner, on Feb. 16, in connec-tion with the annual meet-ing. Mr. Brunton, like several other prominent Institute members, was born in Can-ada, and came to the United States when he was twenty-four years old. He had then been in civil en-gineering work for three years and after a year more of it, deciding that mining was more attrac-tive he spent two years at the University of Michigan doing advanced work in geology a n d chemistry. His first mining engage-ment was with the Dakota and San Juan Mining Co., at Mineral Point, Ouray County, Colo. That was in June, 1875, and the young engineer had to travel 230 miles by trail from the then nearest railroad station at Pueblo. Having to come out because the company did not get in enough supplies to last through the winter he became metallurgist for the Hunt, Douglas & Stewart Co., at Georgetown, Colo. When the Hunt and Douglas plant proved a success, H. A. Taylor, the father of Mr. Brunton&apos;s later partner, Frank M. Taylor, engaged him to build the Clear Creek Reduction Works. Eighteen months later he built the Native Silver Mining Co. mill at Caribou and a year later a mill at Silver Peak, Nev., that was so successful that the principal owner shut it down to freeze out the minority stockholders. The winter of 1879 found him at Leadville where he did engineering work for the Robert E. Lee, Duncan, Wolftone, A. Y. & Minnie, and Dinero mines, eventually becoming manager of the Colonel Sellers. In 1886 he was called in on apex-side-line litigation at Aspen with the result that he went there to develop the mines for economic and legal pur-poses, and later became the manager of three of them. His most notable piece of work there was the driving of

Jan 2, 1927

By Horace Porter

MOST of the bituminous and semibituminous coals of this country Will coke, and all of them yield, on carbonizing, more or less marketable gas and byproducts. We need, however, a finer distinction as between various grades of coking coals and between coals of different degrees of byproduct and gas-making possibilities. There is required by the consumer or the coal producer a dependable test to show whether a certain coal or mixture of coals will make coke of good commercial value for blast, furnace, foundry, water-gas, or domestic use; whether any difficulties in operation may arise from properties inherent in the coal; and whether gas and byproducts may be expected of good quality and in profitable quantity. For determining coke quality, the most dependable test is in actual run in an oven, but for byproducts a coal may better and more accurately be tested in the laboratory or in a miniature oven or retort. As to what are the most desirable qualities in blast-furnace coke, the furnace men themselves are not in complete agreement. Soiree desire a hard, well-burned, "hot" coke, and others get better results from a "greener," less hardened product that burns somewhat more readily in the furnace. But certain qualities of cell structure and porosity are commonly agreed upon as desirable. Information as to what kind of coke a certain coal may be made to yield is valuable in advance, whatever may be the consumer&apos;s ideas as to the particular kind most suitable to his needs. The question arises, Can we predict coking quality with any degree of satisfaction from a small-scale test? It used to be said that coals could not be tested satisfactorily on a laboratory scale either for the coke they would yield or-the byproducts. On account of the mystery with which the coking quality of -coal has been shrouded and the large determining influences that many believe are exerted by mass, pressure, and the passage of carbonaceous volatile matter through the coking material, it has seemed difficult to reproduce in the laboratory the exact conditions of commercial practice. Great progress, however, has been made in recent years

Jan 9, 1919

COMMITTEE OF ARRANGEMENTS. General Committee.-J. F. Lewis, Quinnimont, W. Va. Committee of Reception at Staunton.-Major Jed. Hotchkiss, Chairman ; W. A. Burke, M. E. Miller, R. N. Catlett, W. J. Nelson, J. T. Effinger, D. A. Kayser. Local Committee of Arrangements.-G. T. Wickes, Low Moor, Chairman; G. W. Bramwell, Stone Cliff, Secretary; J. E. Johnson, Longdale; H. Firm¬stone, Longdale; S. F. Morris, Quinnimont; O. A. Randall, Ferrol; William N. Page, Ansted; F. Lyman, Low Moor; S. M. Buck, Coalburgh; E. S. Hutchinson, Cannelton ; M. F. Maury, Saltpetre Cave. THE opening session of the Institute was held at Staunton, on Monday evening, May 30th, in the Opera House. Major Jed. Hotchkiss, Chairman of the Committee of Reception, called the meeting to order and introduced Mayor Balthis, who spoke a few words of welcome to the members present, and then introduced the Hon. A. H. H. Stuart. Mr. Stuart in addressing a formal welcome to the Institute to the " little city of the mountains," spoke of the value of the services of the mining engineer in developing the mineral wealth of Virginia and in solving the problems of her geological history. Mr. Metcalf, President of the Institute, replied on behalf of the Institute to the cordial welcome of the mayor and Mr. Stuart, and then read an inaugural address on Force. At the conclusion of the President&apos;s address the following papers were read The Electrolytic Determination of Copper and the Formation and Composition of so-called Allotropic Copper, by J. B. Mackintosh, Hoboken, N. J. Read by Professor Egleston. The New Unpublished Map of Chester County, Pa., by Professor Persifor Frazer, Philadelphia. The second session was held at the Opera House on Tuesday morning. The papers read at this session were: Investigations on the Ore Knob Copper Process, by Professor Thomas Egleston, School of Mines, New York city. A Volumetric Estimation of Manganese in Pig Iron and Steel, by F. H. Williams, Vulcan Steel Works, St. Louis, Mo. Read by the Secretary.

Jan 1, 1882

By James C. Fulton

Since publication of the First Edition of "Basic Open Hearth Steelmaking," in 1944, this book has been a major reference on the subject of steelmaking. The Second Edition of 1951 was so fundamental that it has retained its general usefulness to the present date. However, recently some of the material has been updated in connection with the writing of a companion book, "Electric Furnace Steelmaking." The sponsor of these two books, the Physical Chemistry of Steelmaking Committee, has felt that the new material should be made equally available to purchasers of either book. Accordingly the subject matter of Chapters 14, 15, and 16 of this new edition is duplicated by corresponding chapters in "Electric Furnace Steelmaking." It was also recognized that the use of oxygen in the open hearth and in the new basic oxygen processes represents a major development that should not be omitted from any basic reference. Thus the major new feature of this Third Edition is the supplement on "Oxygen in Steelmaking." The cooperation of the Iron and Steel Division&apos;s Acid Converter and Basic Oxygen Steel Committee (now merged to form the National Open Hearth and Basic Oxygen Steel Committee) is specifically recognized. In addition to the authors of chapters listed elsewhere, it should be noted that Arthur B. Wilder was the Committee Chairman. Although the changes in the Third Edition are important, the Committee cannot overlook the classic character of the Second Edition. This edition was edited by W. O. Philbrook and M. B. Bever in collaboration with H. B. Emerick and B. M. Larsen. It is anticipated that the Third Edition will maintain the value of the book until the current rapid changes in all basic steelmaking processes stabilize themselves sufficiently to justify a complete revision of the entire text in Part I. The experienced service of Wesley Burr in incorporating the new material in the index is also recognized.

Jan 1, 1964

"Power is transmitted to Butte, a distance of 130 miles, over two separate lines running parallel on the same right of way.The transmission line embodies the most approved ideas in construction. The conductors are No. O. B. & S. gauge, hard drawn copper strand. The insulators are of the suspension type, each insulator consisting of six units, 10 inches in diameter. The insulators will stand a wet test of over 300,000 volts, and were selected after long and careful tests by the company's engineers. The wires are carried on steel towers of four-legged, single crossarm type, manufactured by Milliken Bros. The three conductors are suspended in a horizontal row from the crossarm, and there are no transpositions in either line. Above the power wires and symmetrically located are two galvanized steel strands, Vs-inch in diameter, grounded at each tower, which serve as a protection against lightning.The distance between towers in level country is 600 feet. In mountainous country, however, the spans are irregular in length and spans of 1,500 or 2,000 feet are common. The longest one in the line is that crossing- the Missouri River and is equal to 3,034 feet. The length of this span is such that a person standing at one end of it can sec the wires go off and vanish into space, while the tower at the other end is barely visible to the naked eye on a clear day. The towers at one end of this span arc shown in the accompanying photograph. The line starts at an elevation of 3,200 feet, rises to an elevation of 8,200 feet as it crosses the Continental Divide, and again descends to 6,100 feet, the elevation at Butte.Quantity of coppc1· in transmission line, 1,330,000 pounds.Number of towers, 2,-1-00.Steel used in construction, approximately, 2,-1-00 tons."

Jan 1, 1913

By R. W. Raymond

Prof. Henry Lours, of Armstrong College, Newcastle-on-Tyne, England, a distinguished member of this Institute and other technical societies, has recently sent to the Institution of Mining Engineers, and to the Institution of Mining and Metallurgy, in Great Britain, a communication, the substance of which is as follows : Professor Louis calls attention to the absence of any recognized English term for the definite description of a frequent phenomenon—namely,the oblique position of an ore-body in the plane in which it lies. In this connection, Professor Louis says that in America the term " pitch " has been occasionally applied to this relation, and proposes that, in the literature of ore-deposits, it shall be hereafter restricted to this particular meaning, the angle of the pitch, like that of the dip, being always measured from the horizontal, and the dip being always taken at right angles to the strike, while the pitch is taken on the plane of the dip, in the direction of the strike. Thus, for example, in a vein or bed striking N-S., and dipping, say, 45&apos; E., there might be an ore-body, the axis of which pitched northward, at an angle of 45O below the horizontal line, as measured on the plane of the inclosing vein or bed. If&apos; the term " pitch " had this universally recognized meaning, the situation could be simply and perfectly expressed by its use, in connection with the general data of strike and dip. As Professor Louis says: "This suggestion has a certain practical value, and is not merely academic. Every mining engineer of practical experience in such types of ore-deposit will have met with cases, in which a vertical shaft has been sunk with the object of cutting the deposit, but has missed it, because the dip alone has been taken into account, while the pitch has been overlooked." He adds the acute observation that such an oversight is much likelier to occur with regard to a condition not definitely desig-

Jan 1, 1909

Connecticut Geological and Natural History Survey, P O Box 1106, New Haven, Conn W. E Britton, Superintendent. A complete list of Bulletins available will be sent upon request. Address all inquiries for publications to: George S Godard, State Librarian, Hartford, Conn Fifty-one Bulletins have been issued, 15 of which are of particular interest, dealing with the geology of the state, and are available as follows; 4, The clays and clay industries of Connecticut, by G. F Loughlin (1905), 35 cents; 8, Bibliography of Connecticut geology, by H E Gregory (1907), 20 cents, 13, The lithology of Connecticut, by J Barrell and G. F Loughlin (1910), 45 cents, 18, Triassic fishes of Connecticut, by C. R Eastman (1911), 30 cents, 23, Central Connecticut in the geologic past, by J. Barrell (1915), 20 cents, 24, Triassic life of the Connecticut Valley, by R Lull (1915), 70 cents, 29, The Quaternary geology of the New Haven region, Connecticut, by F. Ward (1920), 60 cents, 30, Drainage modifications, and glaciation in the Danbury region, Connecticut, by Ruth S. Harvey (1920), 55 cents, 33, Geology of the Stonington region, Connecticut, by L H. Martin (1925), 60 cents, 40, The geology of the Shepaug Aqueduct Tunnel, Litchfield County, Connecticut, by W M. Agar (1927), 50 cents; 41, Guide to the geology of Middletown, Connecticut, and Vicinity, by W. N Rice and W. G Foye (1927), $1, 44, Report on the water resources of Connecticut, by R. H Suttee (1928), $1, 46, The physical history of the Connecticut shoreline, by H S Sharp (1929), 75 cents; 47, The glacial geology of Connecticut, by R F. Flint (1929), $2, 51, Minerals of Connecticut, by J F Schairer (1932), 75 cents Bulletin 51 explains the physical and chemical properties of minerals, their classification, and describes more than 100 common minerals found in Connecticut. A bibliography is included The Survey gratuitously distributes all its Bulletins to state residents, scientific institutions, etc. Prices quoted are to private citizens of other states

Jan 1, 1933

By G. C. Wallick, J. S. Aronofsky

This paper presents an experimental verification of numerical solutions of the differential equation describing the transient flow of an ideal gas through a porous material including gas slip effects. Several experiments previously proposed by one of the authors are described together with the correlation of the experimental results with the numerical solutions. Excellent agreement is shown between experiment and theory, thus demonstrating the validity of both the basic assumption made in the derivation of the differential equation and of the numerical solutions of the differential equation. INTRODUCTION In a recent paper,&apos; one of the authors has discussed a numerical solution of the differential equation describing the unsteady flow of an ideal gas through a porous material. This paper was primarily concerned with the effect of gas slip on the flow behavior. In steady state measurements, Klinkenberg2 and others have observed that the apparent gas permeability Kn of a porous material may be expressed as a linear function of the reciprocal average pressure 1/P of the form, ka = b + m/P........(1) where the intercept b is a constant for a given porous material and the slope m is a constant for a given porous material-gas combination. Aronofsky1 assumed that Equation (1) could be used to describe transient flow if P was replaced by the average pressure in an infinitesimal volume element. A number of numerical solutions of the resultant differential equation were presented and specific flow experiments were proposed as a means of testing the numerical solutions. The purpose of the present paper is to describe the results of several of these experiments and the correlation of the experimental data with the results of the numerical analysis. Reference should be made to the previous paper&apos; for details of the mathematical and numerical analysis. EXPERIMENTAL PROCEDURE A simplified schematic drawing of the experimental apparatus is shown in Fig. 1. An 8.89 cm diameter limestone core of length L = 14.82 cm was mounted in a conventional rubber sleeve permeameter cell. The external sleeve pressure in this cell was maintained equal to 500 psig during all experimental tests, thus permitting only longitudinal flow through the core. One end of the core, X = L, was connected to an adjustable cavity of volume V as well as a pressure gauge or manometer. The other end of the core, X = 0, was connected to a Nullmatic pressure regulator which was in turn connected to a nitrogen cylinder or vacuum pump. In each experiment, the core and adjacent dead volume were charged with nitrogen to a uniform gas pressure P1. The pressure at X = 0 was then suddenly raised or lowered to a constant pressure P, and the resulting pressure buildup or pressure decline at X — L was recorded as a function of the time. The porosity + and the permeability constants m and b were determined using the transient method which was suggested by the results of the numerical analysis and which was described in the earlier paper.&apos; The following average values for these constants were obtained as a result of 19 separate evaluations: 171 -0.259 2 0.005 md-atm; b = 0.374 5 0.008 md; and F = 0.098 ± 0.005*. It should be noted that in order that transient phenomena will be slow enough to be observed conveniently, it is desirable to use a porous material of very low permeability, e.g., less than I md. Moreover, it is in this low permeability range that the gas slip effects are most significant. Thus, such a low permeability sample is very suitable for use in an experimental verification of the numerical solutions previously described.

Jan 1, 1955

By A. M. Gaudin

The study that is presented here was undertaken in order to condense information concerning comminution, and covering a great variety of conditions, into one or several rules which would be of use in the development of a systematic theory as well as in many directly practical ways. As the result of this work, the following conclusions appear justified: 1. Rocks may be classified, from the point of view of comminution, into two general classes which are (a) structurally homogeneous, and (b) structurally heterogenous. Structurally homogeneous rocks are those in which fracture takes place through grains and grain boundaries alike; heterogeneous rocks are those in which fracture passes in preference through grain boundaries. 2. If a sized product composed of structurally homogeneous rock grains is crushed, a product results in which the relation between the percentage weight of grains of various sizes and these sizes themselves follows a definite law. This is not true of structurally heterogeneous rocks. 3. Ball milling with structurally homogeneous rocks, and under certain conditions, presents exceptions to this rule. 4. In ball milling with structurally homogeneous rocks, there exists a critical ratio of size of feed to size of balls, above which the machine operates essentially by surface wear, and below which it operates essentially by breaking across the body of the particle. 5. In ball milling, with structurally homogeneous rocks, and when the size of feed grains exceeds the critical size, the particles worn off are of a substantially definite size which depends upon the ball size. 6. In the case of a typical heterogeneous rock, such as Manhattan schist, particles are crushed in such a way that there is a greater proportion of grains of the size that is the average grain-size of the rock than there would be in that range of size with a structurally homogeneous rock. This has been found to be true with all the crushers tested. 7. Different methods of crushing produce grains of different shapes. 8. The importance of sizing the — 200-mesh portion of a crushed product, in crushing-efficiency investigations, has been greatly under-

Jan 1, 1926

By Sir Robert Hadfield

LAST year this Institute was good enough to accept some remarks by the writer regarding sound steel, entitled Plant for Hadfield Method of Producing Sound Steel Ingots, being a continuation of a research in which for some time the writer has been engaged, and full particulars of which were submitted in papers entitled A New Method of Revealing Segregation in Steel Ingots, and Method of Producing Sound Ingots, read before the Iron and Steel Institute in October, 1912. These papers gave rise to a very interesting discussion, both in England and America. This question is one of vital importance, as unless sound steel in the form of ingots is first obtained, sound steel in the finished forms of rail billets, rails, bars, sheets, and other forms cannot be expected. The working stresses demanded by modern conditions are so great, each year they probably approach nearer to the limit of safety, that without doubt those who produce steel will be compelled to pay the attention which this subject deserves. Moreover, the problem is not an insuperable one, as shown by the writer in the papers above referred to. In view of the information which has already been presented in these papers, it is not now necessary to go into details of the system advocated by the writer, except to repeat that the ingots and steel now referred to were produced by employing in the first place sound fluid steel, free from blowholes, this being poured into ordinary ingot molds, provided with the necessary feeding heads, the insulating slag medium, also charcoal and air blast or other suitable form of applying heat to the head portion of the ingot. Tile upper or head portion of the ingot is kept fluid by the intense heat generated by the air blast and charcoal, so that such fluid steel passes into the body of the ingot below the head, thus feeding and avoiding the shrinkage or piping which would otherwise occur. The result is the production of a sound steel ingot, free from blowholes, segregation and piping, and in which the waste portion, usually termed the discard, is but little over 7 or 8 per cent.

Jan 4, 1914

By F. H. Wilson

Copper base alloys containing various amounts of aluminum and silicon are of considerable commercial interest. In particular the alloy containing 7 pct aluminum and 2 pet silicon shows an attractive combination of high strength with excellent, machinability. Since there is no evidence ill the literature that this ternary system has been studied since the recognition by Smith1 and Anderson2 in 1939 of the kappa phase of the binary copper-silicon system, the determination of the equilibrium phase relationships in the copper corner of the ternary diagram has been undertaken to provide a fundamental basis for understanding the behavior of these alloys. Phase boundaries have been determined by the micrographic examination of quenched samples while points on the liquidus surface have been obtained by thermal analysis. The results, of sufficient precision to serve their major purpose of providing a guide for the control of the manufacture of alloys in the region covered, are presented in a series of both isothermal and vertical sections of the diagram. Alloys StVdied For a rough survey of the copper corner of this ternary system the compositions listed in Table I (Series A) were employed. The results of examinations of these alloys indicated that the compositions listed in Table 2 (Series B) would further clarify regions of greater complexity. All alloys were prepared as 1200 g heats, the copper being melted under charcoal, and then first silicon and then aluminum were added. An excess of 0.05 pet silicon was allowed to cover deoxidation losses. Two small bars 5/8 by 1 1/4 by 5 1/4 in. were cast using Durville type casting equipment. Ailalyses were made on all alloys using material which was hot-rolled at 800 or 850°C and annealed 17 hr at 650°C. All analyses were found to be within 0.05 pet of the nominal composition. Since the precision of analysis is not much better than this, the points of both isothermal sections and vertical sections at fixed aluminum and silicon contents have been plotted at the compositions indicated by the nominal composition.

Jan 1, 1949

By R. H. Marshall, J. Welchner, E. S. Rowland

THIS paper presents results on an exten¬sion into the realm of high-carbon steels of some work recently published&apos; on the effects -of time at temperature, quenching temperature and prior structure on the hardenability of one 0.20 and four 0.40 per cent carbon alloy steels. It was shown at that time that unless the conditions of time, temperature and prior structure are substantially the same in performing the hardenability test as in conducting harden¬ing of parts in production, the correlation of hardenability information with the [ ] hardness and properties of production parts is often not of satisfactory accuracy. The general effects of these variables on the austenitic grain size, distribution of excess carbides and critical cooling rate have been known for many years and one or more have been investigated by Shepherd ,2 3 Davenport and Bain,4 Digges,5,6 Digges and Jordan,7 Post and associates&apos; and Roberts and Mehl,9 to mention only a few. There has been no systematic investigation, however,&apos; into the quantitative variations produced on the hardenability of commercial high¬carbon steels by changes in these factors of time, temperature and prior structure. PROCEDURE A plain carbon hypereutectoid steel, S.A.E. 52100 and Graph-Mo, a molyb¬denum-bearing high-carbon steel contain¬ing some graphite, were chosen for this investigation. The chemical analyses of these electric-furnace steels are given in Table I. [ ] The procedure used was exactly that reported previously,&apos; hence the details will not be repeated here. Normalized (1650°F.) and spheroidized prior structures were utilized on all steels with hot-rolled and quenched (1600°F. oil) prior conditions added for the plain carbon steel. The end-quench test developed by Jominy10 was selected for use in this investigation and, with the noted exceptions, the American Society for Testing Materials standard. procedure was followed. The effect of time at temperature was examined at intervals of 0, 10 and 40 min. and 4 hr., and a few i6-hr. tests were run. Salt-bath heating of the specimens was employed to control and minimize the

Jan 1, 1944