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By Guang Ping Cui

In this paper the imminent relationship between rock burst and its phenomenon with normal rock pressure and its appearance, as well as the factors of one changing into another have been analyzed. Based on this, the necessary and sufficient appearing factors of rock bursts have been put forward, and the term ''burst pressure" has been defined. According to the statistics data of tremendous rock bursts which appear in collieries in Hunan Province, the features of high frequency, great strength and shallow depth of the beginning burst have been found. There are some special structures in the coal seams, which are closely related with the burst phenomenon. A hypothesis of "star structure" has been suggested for the appearing mechanism of bursts. Inside and around this star structure the distribution rule of burst pressure and rock strength has been researched depending upon the theory of the limited stress field. A new description of the appearing causes of bursts has been raised.

Jan 1, 1984

By E. V. Foran

AMONG the many newer disclosures that have accompanied the petroleum industry's progressively deeper exploratory drilling is the increased frequency with which the operators are encountering reservoirs of which the products at the time of discovery exist wholly or predomi-nantly in the gas phase. The popular term "distillate pool" is most often used within the industry when referring to this type of reservoir, and in this paper the term is used in that sense. These pools have been observed in many different surroundings. In some places the entire reservoir is filled with the wet gas containing its water-white condensible products in the gas phase but apparently with no dark oil or other hydrocarbon liquids in the reservoir. The 8200-ft. horizon in the Big Lake field in West Texas is a good example of this type. At other places the wet, or distillate-bearing, gas may form a large gas cap directly overlying and in contact with an extensive reserve of dark oil. Oklahoma City, Kettleman Hills, the 8500-ft. horizon in the Big Lake field, and many others are examples of this type. There are also many places in which the wet distillate-bearing gas fills nearly the entire reservoir space, while the dark oil occupies only a narrow, bandlike zone, which marks the boundary of the reservoir along its lowest productive contour. The heavier components of these deep pool gases are generally water white in color, a large portion of which are condensible in a conventional oil and gas separator, when operated under pressures of the order of 400 to 800 lb. per sq. in. Although the water-white products recovered in the separator sometimes have end points of 650° F. and higher on standard Engler distillation, they occur only in the gas phase in the reservoir. It is entirely possible that even some small amounts of dark colored reservoir components may occur in the gas phase when the temperature is 300° F. and pressures exceed 6000 lb. per sq. in. Close approaches to these conditions have been encountered in the deepest producing wells. The condensible content of the deep reservoir gases of the many pools that have been tested or produced to date shows a wide variation in both condensible content, per 1000 cu. ft. of gas, and physical character.

Jan 1, 1939

The Library belonging to the Institute is now administered as part of that of the United Engineering Society, the members of the Library Committee representing the Institute on the Library Board of the United Engineering Society. The main collection now consists of 115,900 books, 3680 pamphlets, 5811 maps, and 4402 searches, making a total of 129,793, a net gain of 7701 within the year. There is in addition a lending collection of 1004 volumes and one of duplicates amounting to 11,310. The library grows steadily both by gift and purchase. The cataloging is now substantially current covering 124,100 items represented by 362,145 cards. There are many rare and notable books, especially those relating to early engineering. It is truly a great treasure house of knowledge. While no severe effort is made to record all visitors the books showed 23,470 to have used the Library in 1928. In addition 5102 telephone requests for information were answered, 202 searches and 196 translations made and 34,964 photo prints furnished. The service department is maintained by small fees which cover the cost. The total amount appropriated for operating expense for the year was $46,300, of which $8,240.02 was furnished by the Institute, $5,399.45 being derived as income from the Douglas Library Fund and the remainder from current receipts. Within the year a slight change was made in the method of meeting the expenses of the Library, a flat charge of $5,000 per year being made against each of the four Founder Societies and this being supplemented by a surcharge based upon membership. The effect of this has been for the present to decrease slightly the amount that the Institute would otherwise need to pay. Placing in one collection all the books of the four societies greatly increases the number of books accessible to the members of each and opening the Library to the public is an important factor in keeping the tax exemption privilege enjoyed for the building. The Director and Staff of the Library make every effort not only to accommodate those who come in person to consult the collection but members resident elsewhere who communicate by letter or wire. The facilities of the Library are truly available to all.

Jan 1, 1929

By James F. Lewis

The hematite iron ore mines east of the Hudson River are confined to a strip of country ten to fifteen miles wide, commencing on the south, near Fishkill, running northeast through Dutchess County, and striking the southeast corner of Columbia County, extending into Litchfield County, Conn., known there as the Salisbury mines, cropping out again at and near West Stockbridge, Lanesboro, and Cheshire, Mass., also in Bennington County, Vermont. The ores are found in beds or deposits and in veins, with a limestone ledge on one side and slate on the other, from six to thirty feet from the surface. Portions of it are quite solid, called rock ore, but

Air-sand Process of Cleaning Coal Discussion of paper by THOMAS FRASER and H. F. YANCEY, presented at the New York Meeting, 1926, and issued, as Pamphlet No. 1561-F, with MINING AND METALLURGY, February, 1926. T. DEVENNY, Edgarton, W. Va.-How near the size of the sand can the coal to be treated be brought? Do you use an 8-mesh coal on that cleaner? J. J. RUTLEDGE, Baltimore, Md.-From the little I have seen of the apparatus in operation, I should say 8-mesh. In my experience in metalmine concentration work, trying to separate different minerals on one jig, sometimes I have succeeded and sometimes not. This apparatus has appealed to me; something of this kind should be useful with the silicates and carbonates of zinc. I think this apparatus has possibilities in metal mining. Recently in our coal field a screen has been introduced for cleaning coal; it is giving excellent service. When I asked the inventor why he did not take it to the metal mines, he said there was a good and sufficient reason, in a patent way. There may be reasons why it would not be applicable for metal mining; but the simplicity of it appeals to me and I cannot see why it could not be so used. T. FRASER (written discussion).-We feel that 8-mesh would be about -the minimum size of coal practicable to treat by the air-sand process. This would depend partly upon the friability of the coal. The more nearly the lower size limits of the coal- approaches the size of the sand, the more .time will be required in screening the sand out of the cleaned coal, which would mean a little more chance of breakage. In regard to the treatment of ores; this would necessitate the use of some heavier mediums than ordinary silica sand, or some other means of making the separation at a higher specific gravity than is required for coal. We are now working on a method of obtaining this effect for the preparation of anthracite coal without resorting to the use of heavier and more expensive material than common sand.

Jan 1, 1927

Jan 1, 1970

By O. W. Rees, Gilbert H. Cady

Unit coal calorific values represent a close approach to pure coal values; they possess characteristics theoretically inherent in the latter values. They are essentially uniform in the same seam for areas possessing essentially uniform geological environment. They are higher in older than in younger coals in most cases, and in deeper than in shallower coals. In general, they display characteristics closely in accordance with expectation assuming that they are essentially indices of rank. Because it possesses these characteristics, the unit coal value is essentially a standard value, characteristic of each bed in each local region. Hence it can be used as a basis for determining the accuracy of results in newly established laboratories, or when new equipment is installed, or in checking the results of different laboratories, or even in determining the character of coal as mined or prepared if ash, moisture and sulfur values are known. DISCUSSION (A. C. Callen presiding) R. P. Hunson,§ Wayland, Ky. (written discussion).—One of the interesting observatioris made by the authors is that there is a more or less definite correlation between unit coal calorific values and the geological environment of the coal bed. It is very interesting to note that, in general, the unit B.t.u. value increases with the increase in the probable original depth of burial, and that each seam tends to increase in calorific value toward the areas of diastrophic instability. It is generally conceded that Parr's formula, for determining unit coal values, is about as accurate as any formula subsequently proposed for the same purpose. In his formula, Professor Parr did not differentiate between the sulfur present as iron pyrites and that present as organic sulfur. However, the practical application of the formula has shown that this is of little consequence. I agree with the authors that unit coal calorific values are useful ill determining the accuracy of calorimetric determinations, and in determining the character of the

Jan 1, 1934

BLAMEY STEVENS, Nogales, Ariz. (written discussion *).-This subject should be approached boldly from the purely physical standpoint. There are usually many known ways of making chemical deposits of any particular mineral and probably many more ways that are still unknown. With-physical-effects; .however, there-are, in-general, only one or two, or possibly three, ways that will pass muster before the physicist, when he realizes the geological conditions to be harmonized with the physical ones. Let us consider the second way that Mr. Taber describes: "It (the mineral matter transported in solution) may enter along a fracture, bedding plane, or similar passage, and, as it is deposited, force the wall rock apart, thus making room, for the growing vein," because it is the one Mr. Taber chooses for the great bulk of metalliferous veins. By "forcing the wall rock apart" Mr. Taber indicates that he means that the process of crystallization or-solidification of the mineral in the vein forces the walls apart. To prove this, he offers a great variety of geological evidence, which, from the physical standpoint, is entirely superficial. From the geological standpoint the evidence is the best to be had, but it is entirely negative and one single grain of really positive evidence will entirely offset it. Suppose it be granted that there is a considerable force of crystallization. It is well known among physicists that, other circumstances being equal, the crystal would rather form where it does not have to exert that pressure; or, to be more exact, where it is not necessary for the crystal to

Jan 12, 1918

By James E. York

The honor so fairly earned and so incompletely and tardily paid to Henry Cort, the inventor of the puddling-furnace and the rolling-mill, has been fully set forth by Mr. Charles H. Morgan,' and needs no further emphasis here. In view of the importance of the rolling-mill in the treat ment of iron and steel, the paucity of information concerning it is surprising. With the exception of a book, written about 35 years ago, by Peter Ritter von Tunner, an Honorary Member of this Institute, and of desultory articles on simple sections, which have appeared in technical journals, I know of no publication attempting to treat this subject, although volumes have been written on the scientific theory and technical manipulations involved in other branches of the iron- and steel-industry. This strange anomaly may be due to the fact that roll-turning cannot be called a scientific business. It does not ordinarily come within the range of an educated engineer; yet it cannot be performed by an ordinary mechanic. It demands some of the qualifications of an engineer, in designing, and those of a mechanic, in execution. The men who have followeci this trade have controlled the training of their successors. In many cases the technical knowledge required has

Jan 1, 1907

By Gilbert Soler

THIS year's Chairman of the Iron and Steel Division is a noted member of a small and select group of practical scientists now working in this country and in Canada to improve the production and properties and to reduce the cost of super-quality carbon and alloy steels; he is one of those all-important leavening agents-a man with his feet always on the ground but capable of putting his head into the clouds on occasion-that are so necessary in applying science sensibly to the practical problems of steel production. He is equally at home in a discussion of the free energy of deoxidizing reactions or the entropy of the formation of stable sulphides, and in a consideration of the relative advantages of the basic-electric and the open-hearth furnace for the production of rimming steels in the Detroit area. Gilbert Soler was born of American parents in Havana, Cuba, just forty years ago. He graduated as a ceramic engineer from Ohio State University in 1930 and received a Master of Science degree a year later. In 1940 he received the degree of metallurgical engineer from the same institution.

Jan 1, 1948

EXECUTIVE COMMITTEES OF LOCAL SECTIONS New York Meets first Wednesday after first Tuesday of each month. DAVID H. BROWNE, Chairman, JOHN H. JANE WAY, Vice-Chairman. F. E. PIERCE, Secretary, 35 Nassau St., New York, N. Y. P. A. MOSMAN, Treasurer. Boston Meets first Monday of each winter month. HENRY L. SMYTH, Chairman. ALFRED C. LANE, Vice-Chairman. HENRY A. WENTWORTH, Secretary-Treasurer, 60 India St., Boston, Mass. ROBERT H. RICHARDS, ALBERT SAUVEUR. Columbia Holds four sessions during year. Annual meeting in September or October. FRANK A. ROSS, Chairman. RUSH J. WHITE, Vice-Chairman. LYNDON K. ARMSTRONG, Secretary-Treasurer, P. O. Drawer 2154, Spokane, Wash. FREDERIC KEFFER, FRANCIS A. THOMSON.

Jan 6, 1915

By Arthur H. Redfield

The West Indies are the summits of a submerged mountain chain, the continuation of which must be sought in the mountains of central Honduras. In Haiti, the chain divides, one branch passing through Jamaica and the other through Cuba, the Cayman Islands, and the Misteriosa bank. Suess divides the West Indies into three zones: The first zone is entirely of volcanic origin and includes many recent volcanic cones. It includes the arcuate string of islands, which extends from Saba and St. Kitts to the Grenadines and Grenada. The western half of Guadeloupe belongs to this group. The second zone consists of a geanticline, of which the sedimentary rocks range from the Jurassic to the Quaternary, but consist chiefly of Lower Tertiary sediments. In the west it is broad, including the whole of the Greater Antilles; but in the east it is restricted to a narrow belt, which includes the Virgin Islands (except Anegada), Anguilla, St. Bartholomew, Antigua, the eastern part of Guadeloupe and part of Barbados. The islands that compose the third zone are flat and low. Like the second, this zone is broad in the west and narrow in the east; it includes the Bahamas, Anegada, Sombrero, Barbuda, and part of Barbados. Geologically, Florida and the plain of Yucatan may be regarded as belonging to it. Trinidad and Tobago, though geographically adjacent to the Lesser Antilles, are geologically a detached part of the South American continent. The crystalline complexes of northern Trinidad and of Barbados are a continuation, en echelon, of the crystalline axis of the promontory of Paria. The folded Cretaceous and Tertiary of the central and southern parts of Trinidad represent a continuation of the folded sedinlents of the Paria district of Venezuela. Possible Oil-bearing Areas The volcanic islands of the inner arc of the Lesser Antilles may be excluded from consideration; these include Saba, St. Kitts, Nevis,

Jan 1, 1923

By Arthur H. Redfield

The West Indies are the summits of a submerged mountain chain, the continuation of which must be sought in the mountains of central Honduras. In Haiti, the chain divides, one branch passing through Jamaica and the other through Cuba, the Cayman Islands, and the Misteriosa bank. Suess divides the West Indies into three zones: The first zone is entirely of volcanic origin and includes many recent volcanic cones. It includes the arcuate string of islands, which extends from Saba and St. Kitts to the Grenadines and Grenada. The western half of Guadeloupe belongs to this group. The second zone consists of a geanticline, of which the sedimentary rocks range from the Jurassic to the Quaternary, but consist chiefly of Lower Tertiary sediments. In the west it is broad, including the whole of the Greater Antilles; but in the east it is restricted to a narrow belt, which includes the Virgin Islands (except Anegada), Anguilla, St. Bartholomew, Antigua, the eastern part of Guadeloupe and part of Barbados. The islands that compose the third zone are flat and low. Like the second, this zone is broad in the west and narrow in the east; it includes the Bahamas, Anegada, Sombrero, Barbuda, and part of Barbados. Geologically, Florida and the plain of Yucatan may be regarded as belonging to it. Trinidad and Tobago, though geographically adjacent to the Lesser Antilles, are geologically a detached part of the South American continent. The crystalline complexes of northern Trinidad and of Barbados are a continuation, en echelon, of the crystalline axis of the promontory of Paria. The folded Cretaceous and Tertiary of the central and southern parts of Trinidad represent a continuation of the folded sedinlents of the Paria district of Venezuela. Possible Oil-bearing Areas The volcanic islands of the inner arc of the Lesser Antilles may be excluded from consideration; these include Saba, St. Kitts, Nevis,

Jan 1, 1923

By William Metcalf

One of the first questions that naturally occurs to one who handles steel is, " Why does steel harden?" To answer this question the chemist and physicist have devoted much thought and experiment, and while they have enriched our store of knowledge of the nature and composition of steel, it cannot be said that they have yet solved the problem involved in its hardening. In this communication I desire to direct attention to a line of investigation yet new, in the hope that it may receive the attention. of those who have the time and ability to pursue it. I refer to magnetism. There are so many parallels between the action of magnetism on iron and steel and their behavior under different processes of manipulation that it would seem. as if there must be some connection between tile forces at work in the different cases, if, indeed, there be not an identify of force in all of these cases. Magnetism, as me know it, may be merely the visible manifestation of forces, which may serve as a guide to lead us to an exact knowledge of the structure, tile strains, and the resistances with which me have to deal in iron and steel. If a magnet be brought close to a pile of iron filings, the little pieces of iron will fly to the maguet and attach themselves to it, with their longer axes lying in the direction of the force. If molten cast iron be poured into an iron mould,—a chill,—the iron upon crystallizing will form needlelike crystals, with their long axes normal to the surfaces of the mould. • If the iron is at the proper temperatare and the quantity small, compared to the mass of the mould, the whole of it, will be chilled, or set, in 'the hard needlelike crystals

Jan 1, 1881

By David Baker

When the skip-hoist was first tried as a means of filling the blast-furnace it made a great many enemies and very few friends among furnace managers. This state of affairs continued until the Duquesne furnaces were built, which demonstrated not only the possibilities of a furnace-stack in the way of production, but also the ability of the skip-hoist to charge the materials necessary to produce the large tonnlage obtained. Every furnace manager, who has operated stacks fitted with the vertical hoist and the hand-barrow system of filling, remembers that the momentous question about the furnace, particularly during a good run, was: "Are you keeping her full ?" and many a good run has been spoiled by the furnace " getting away from the men." With the new birth of the skip-hoist this trouble was eliminated ; but alas! Other and more important difficulties arose. The distribution of the stock, the importance of which is never learned until many different ores and fuels have been tried, demanded closer attention. With all the defects of the hand-barrow system, the distribution—When the top fillers were conscientious in carrying out the scheme of filling arranged after thoughtful consideration by the manager—mas above criticism. It is said that the modern skip-hoist, equipped with an elliptical hopper and receiving-cylinder, and discharging over a small bell into the main hopper, will give just as good results as those obtained with hand-barrow charging, but I cannot agree with this statement. I grant, that under very favorable conditions, the mechanical furnace-top will do apparently as well as the

Jan 1, 1905

By Clarence Claghorn

ONE of the simplest and most easily effected steps toward mechanization and concentrated mining in coal mines is the substitution of transport or room conveyors for the customary tracks in rooms, thus bringing the coal to the cars instead of taking the cars to the coal. As this involves little or no change in the established room and pillar layout, it appeals to the conservative operator who is more or less fearful of changes in system involving the element of roof con-trol. An increasing number of these room conveyors would seem to attest the favorable commercial results secured. Rooms are naturally driven as wide as roof conditions permit, providing maximum tonnage from each room cut. If the rooms are more than 12 to 14 ft. in width the room conveyor is usually set along one rib, a porta-ble face conveyor being set along the face itself and within easy shoveling distance of it, so arranged as to discharge to the transport conveyor. As the room ad-vances the latter is lengthened and the face conveyor moved up laterally. The advantages of this layout are, briefly, low lifts, no shoveling, no waiting for cars. It gives easy shovel-ing conditions and continuous production so long as there is loose coal at the face. Several loaders are usually employed at the face and the room is loaded out several times each shift. In fact, where the rooms are fairly wide, by judicious management, cutting and load-ing may go on simultaneously. Under these conditions, naturally, the face conveyor plays an important part as it is the appliance on which the coal is actually loaded. Someone has aptly stated that the loading is a question of "foot pounds," which is an appealing way to put it, for it is the number of pounds to be moved by the number of feet which measures the work to be done. It can easily be seen that the design of the face con-veyor is a matter of importance. It might be an im-perfect target for the shovel or of an awkward shape and height, and so involve extra effort on the part of the loader, tiring him when kept up continuously and at the same time slowing up his shoveling speed.

Jan 12, 1927

Redetermination of the Chromium and Nickel Solvuses in the Chromium-Nickel System by C. J. Bechtold and H. C. Vacher, p. 14 The text of pages 16 and 17 is in improper sequence. The correct version will appear in the bound volume.

Jan 1, 1962

IN the extra-mural service being built up by the Engineer-ing Societies Library as its finances permit, an occasional large total charge is incurred for exceptionally protracted services. A western steel company, for example; was charged the unusual fee of $500. They wanted complete informa-tion on transverse tests of steel, and asked the library to compile copies of all accessible records. Weeks -of search-ing and photoprinting produced three volumes of data. Two years afterward the company's chief engineer told the director of the library that the cost seemed high when the bill was paid but that the volumes had been in constant use. The information had been worth thousands of dollars. A client who wishes to pay no more than a moderate fee for services can state to what limit he is willing to go. Thus he may specify that he would like searches made on a particular subject but that he does not wish to exceed $5 or $30- for the information. The library is as willing to perform a small service as a large one.

Jan 3, 1928

Jan 1, 1932

By Lyall Zickrick

Numerous brands of virgin pig lead are used in the manufacture of lead and lead-alloy cable sheath for commercial cables. In changing from one brand of pig lead to another a readjustment of press operating conditions is nearly always necessary. This is due largely to different flow characteristics, and some brands extrude at a much lower pressure than others; for example, copper-bearing lead requires much more pressure than a low-bismuth lead under the same operating conditions. With the modern type of lead press the extrusion practice in general differs very little. Molten lead at a temperature of 375" to 400" C. (710" to 750" F.) is cast in a water-cooled cylinder and allowed to cool or solidify into a slug for six to nine minutes, This slug is forced into the die block and around the core tube through which the cable runs. The • die block is held at an optimum temperature by means of gas flames, usually 175" to 225" C. (350" to 435" F.). Measurements of the temperature of the cable sheath taken at the time of extrusion have covered a range of 190" to 225" C. (375" to 435" F.). According to Tammann, the rate of extrusion for a metal under constant pressure through a simple orifice is almost doubled for each 10" C. rise in temperature. Because of the irregularity of die-block construction, such a great increase is not obtained in lead-cable extrusion practice. To obtain more definite information about the effect of small percentages of metals usually present as impurities in virgin pig lead, a series of compression tests were made covering several different brands of lead and various alloys. Since the usual temperature of the sheath is approximately 200" C. as it emerges from the die block, these compression tests were all performed at 200" C. Five different brands of virgin pig lead were selected, as follows: Brand A: A desilverized western lead of very high purity. This lead contains neit,her copper nor bismuth. Brand B: A bismuth-free southeastern Missouri lead, usually containing 0.05 to 0.08 per cent copper. Brand C: A copper-free mid-western desilverized lead of very good grade, usually containing around 0.06 to 0.10 per cent bismuth.

Jan 1, 1932