Search Documents

By J. A. Fulton, A. B. Foote

Gold was discovered in the Sierra Nevada by J. W. Marshall on Jan. 2, 1848. The town of Grass Valley soon sprang up and contained several stores in 1849; but the population of the town has always reflected the fluctuations in quartz mining. Gold-bearing quartz was found on Gold Hill in September 1850, and in the next two years most of the quartz-bearing veins in the vicinity were located. At first, the quartz was crushed in mortars with spring poles; the IIuff Co. took out $20,000 in this manner during the winter and spring of 1851. The first mill was put up in January, 1851. In 1866, there were in Grass Valley 248 stamps, crushing 71,420 tons of ore with an average yield of $30 to $35; in Nevada City, there were 142 stamps, crushing 14,200 tons, with an average value of $25. Rut in 1918, only two properties in this region, the Empire and the Korth Star, were producing Since then, there has been a revival of mining in the district and the following properties are being opened up: The Golden Center. Grass Valley Gold Mines Co.. Idaho-Maryland Mines Co., while the Su1tana is kept unmatered and work is going on in a half dozen mall propertics Mining Claims At the first meeting of miners in Grass Valley, Jan. 13. 1851, a plot :30 by 40 ft. was allowed for a claim, the boundaries in all cases being perpendicular. In 1852, the quartz miners in Nevada County deeided that "each prospector shall hereafter be entitled to 100 ft. on a quartz ledge or vein and the discoverer shall be allowed 100 ft. additional. Fach claim shall include all the dips, angles, and variations of the vcin." This rule was in force until replaced by the Federal mining laws of 1872; these allowed quartz claims to be 1500 ft along the vein, with all the dips, spurs, and angles, and to have a width of 600 ft. The holdings of the principal companies consist of these early patented mining claims; standard claims, as authorized by the Act of 1872, both patented and unpatented; agricultural tracts, both patented and

Jan 1, 1927

By J. W. Gwinn

THE underground haulage system in the lead-silver mine of the-Bunker Hill & Sullivan Co., situated at Kellogg, Idaho, is the most extensive in the Coeur d'Alène district, comprising about 35,000 ft. of tunnels, drifts, and cross-cuts where locomotive haulage is in use. The main working adit, known as the Kellogg tunnel, or No. 9 level, is approximately 10,000 ft. in length from the portal to the main working shaft and extends beyond that about 4,500 ft. in each of two directions. On this level all the ore from the Bunker Hill & Sullivan, the Sierra Nevada Consolidated, and the Caledonia Mining Co. an average of 44,600 tons per month-is hauled to the mills, located a short distance from the portal. Electric haulage by the trolley-type locomotive is used on this level throughout. Below this level, at intervals of 200 ft. vertically, are five other working levels (Nos. 10, 11, 12, 13, and 14); and the total haulage distance on these, where electric locomotives are used, is approximately 16,000 ft. No. 13 level has but recently been opened up and is not working-to capacity; while the main cross-cut on No. 14 has just been started, and has no need of power haulage. Of the four levels equipped with electric haulage, Nos. 11, 12, and 13 have storage-battery locomotives, and No. 10 still retains the trolley type by reason of the small and decreasing tonnage produced.

Jan 2, 1915

By C. D. Keen

IN the latter part of the summer of 1913 the Conservation Commission of the State of Louisiana, under presidency of M. L. Alexander, decided to stop the waste of natural gas going on at the "burning gas-well," located about 3/4 mile southeast of Oil City, La. On several occasions, both in newspapers and in reports, comment had been made on the condition of this well, its harmful effect on the Caddo gas field, and the considerable loss, estimated at several thousand dollars each month, caused by the escape of the valuable fuel. But nothing had been done to bring the well under control and prevent further waste of gas until the State Conservation Commission took the matter in hand. The gas fields of Louisiana are among the greatest in the country. So far most of the gas has been found in the Caddo field proper, although considerable development has been done in and around the city of Shreveport and near the town of Mansfield in DeSoto parish. To extend the life of the gas fields and to prevent the quick exhaustion of the supply of the natural fuel are matters of vital importance for this section of the country. Four gas companies have entered the Caddo field and supply the surrounding towns and cities with gas. The Arkansas Natural Gas Co. has pipe lines to Little Rock, Ark., and supplies gas to the following cities and towns in that State: Texarkana, Hope, Garland, Emmet, Prescott, Boughton, Beirne, Gurdon, Arkadelphia, Gum Springs, Malvern, Donaldson, Gifford, Perla,- Beaton, Beauxite, Mabelvale, Bryant, Sheridan, Pine Bluff, Little Rock, Argenta, Pulaski Heights, and Hot Springs. The Southwestern Gas & Electric Co. transports gas to Mooringsport, Blanchard, Caddo, Rodessa, Oil City, Vivian, Bloomburg, Hosston, Ida, Dixie, Belcher, and Shreveport. The Marshall Gas Co. supplies gas to the town of Marshall, Texas. The Louisiana Co. has a line to Shreveport.

Jan 3, 1914

By R. G. Knickerbocker

The copper smelter and refinery of The Messina (Transvaal) Development Co. Ltd., at Messina, South Africa, was erected in 1920 and 1921, but initial operations were deferred until late in 1922 on account of the collapse of the copper market in the interim. Because the anticipated production was to be only 20 tons of copper per day from a high-grade matte containing 60 per cent copper, and because the ore did not contain gold or silver in quantities sufficient to pay for separation from the copper bullion, it was decided to design the plant along lines quite different from the modern smelteries treating large quantities of sulfide ores carrying appreciable amounts of gold and silver. The plant was built, therefore, for the production of copper by the Nicholls-James process. By this method two-thirds of the copper matte produced was roasted in a Merton calciner and charged into a bath of the remaining one-third portion of unroasted matte in a reaction furnace. The original design was not only novel in providing for the Nicholls-James process, but also in comparison with new plants built elsewhere, because of factors inherent in the locality. Sources of supply for machinery were very remote; it takes three months after the placing of an order to accomplish delivery of machinery into Messina from the United States. Native labor was available at 30 to 40¢ per 8-hr. shift. These factors permitted plant design which provided no overhead cranes, no matte ladles, no slag pots or other usual mechanical means of transportation between departments. The design resulted in a compact simple plant with furnaces arranged close together and terraced so as to provide for gravity transfer of molten material from one furnace to another and for manual disposal of products. Fig. 1 shows the relative location of furnaces. The three furnaces are parallel on successively decreasing elevations. A superimposed feed floor was provided above the furnaces. All three furnaces were provided with coal-dust burners served from a Bonnot system of coal-dust transportation, and the waste gases were discharged into waste-heat boilers. A short trial of the Nicholls-James process developed several facts which brought about a decision to abandon the process. Owing to the

Jan 1, 1934

By P. Nicholls

Though the burning of fuels extends far back into antiquity, and though fuel beds are the most common and widely distributed example of chemical actions and engineering practice, there has been little attempt to group fuel beds by types or to define the principles associated with them. This paper does not profess to cover completely the subject of fuel beds. It suggests some of the over-all principles of the two more common types. No new investigational data are included, but the deductions are largely based on a recent publication of the U.S. Bureau of Mines'. Definition of Types There are three primary types of fuel beds: (I) Underfeed, in which the fuel and the air move in the same direction; (2) overfeed, in which the fuel and the air move in opposite directions; (3) crossfeed, in which the fuel and the air move at right angles to each other. The principle that fixes the type is the relation between directions of the flow of fuel and of air. Fig. 1 shows the three types diagrammatically. All other types are compounded of these three in a simple or more or less complex manner. It does not follow that these three type designations are limited to the methods used in representing them in Fig. 1; they may be turned in any direction, and as long as the relative directions of the fuel and air are the same the type is not changed. For example, A as shown .resembles a pot-type stoker, but the air and fuel can move downward as in the so-called smokeless heating boiler furnace. Also, C can be placed horizontal, as in chain-grate stokers. For this reason, the terms used to designate the three types are not all that could be desired; more logical ones could be coined, but those used probably are satisfactory until the discussion of fuel-bed types becomes more common.

Jan 1, 1936

By Hermann Wedding

I ASK your permission to speak about a matter which is not of a specifically scientific nature, but more of a general-I might even say of an international-nature, and the international character which this city now presents must be my justification for introducing it. The Germans, very often, are thought to be an exceedingly warlike people, but I come to-day in the capacity of a peacemaker. Our German language is an original language; it is, therefore, a language in which it is impossible to change the meaning of a word at will. It may be, perhaps, easier in a combined language, as the English, to associate and to exchange meanings. Now, a word which we hear a great deal at the present day, is "Stahl," in English, "steel." This word means, in the German language, a substance which can be hardened. As the German literature, in relation to metallurgy, is the oldest of the modern world, this circumstance may give the German a right to ask for consideration. But I think, now, when the four languages, German, Swedish, French, and English, compete in rich metallurgical literature, it is very necessary to have uniformity in the nomenclature of iron, which would prove not only useful for science, but equally so for trade. For that purpose I propose to make the divisions of iron so that the word steel shall comprise a subdivision and not a primary division as formerly. Nature furnishes us iron mostly in the state of oxides, and if in any other condition, we must convert the ore into oxide before we can make iron. The oxides are always mixed with certain earthy substances called rock or gangue. The extraction of iron involves, therefore, the twofold process of the reduction of the iron, and im¬parting to it the amount of carbon necessary for technical purposes, and the separation of the reduced and carburized iron from the gangue. The reduction is always effected by carbon or carbonaceous substances (coke, anthracite, carbonic oxide, etc.), and the result is, according to the degree of heat employed, either malleable iron or a non-malleable iron. The process of making malleable iron in this way is called, generally, the direct process-in German, Rennarbeil. It produces the iron in a solid state with a fluid cinder. By this process our ancestors made all their iron, and it has been revived in various ways in modern times up to the process of Mr. Blair, so far as I know, always without commercial success. The

Jan 1, 1877

By W. A. Bates, R. J. Miller

Although cresylic acids have been standard frothers in flotation for many years, there has been little discussion of their nature in the metallurgical literature. Aside from references in the patent literature, the paper by Landolt, Hill, and Lowyl in 1930, which resented a study of the frothing and collecting properties of some of the constituents of crude cresylic acids, represents the only contribution of this type. The close froth control required in the delicate selective separations of present-day flotation operations have required the flotation metallurgist to choose his frothers with care, and have caused him to require of the manufacturer a closely controlled, uniform product. A background of knowledge of the chemical composition and physical and chemical properties of the frothers, by which their action may be correlated, should aid in selecting frothers for particular flotation requirements. Further, the recent almost complete replacement in flotation of coal-tar cresylic acids by those derived from petroleum makes it especially desirable to review the flotation behavior of the acids from the old and the new sources. In view of these facts the Milling Methods Committee of the A.I.M.E. suggested to the Oronite Chemical Co. of San Francisco the preparation of a paper on the subject, and this paper has accordingly been prepared as a contribution by the California Research Corporation, the research affiliate of the Oronite Chemical Co. The discussion is from the following aspects: (I) constitution and properties; (2) sources; (3) comparison of coal-tar and petroleum cresylic acids; (4) characteristics as frothers, with particular reference to the effect of the substitution of petroleum acids for coal-tar acids. Constitution and Properties Cresylic acids are commonly regarded as mixtures of orthocresol, metacresol and paracresol. This was, indeed, the former meaning of the term, but in recent years it has been loosely applied to any mixture of alkyl phenols boiling above 190°C.; that is, excluding only phenol itself. This means that cresylic acids, as they are known today, may consist of mixtures, not only of the three isomeric cresols, but of six xylenols and of a variety of higher boiling homologues. Generically the constituents of cresylic acids are alkyl phenols, and they are often so designated in the literature to avoid the more indefinite term, "cresylic acids." They form an homologous series starting with phenol, which has the familiar benzene ring, with an hydroxyl group in place of one of the hydrogen atoms. The series of alkyl phenols is formed by the substitution of alkyl side chains, such as methyl, ethyl, propyl, butyl, etc., for hydrogen atoms of the benzene ring of phenol. Some

Jan 1, 1947

By N. W. Sager, H. W. Mossman

The arrangement and general dimensions of the reverberatory furnaces and waste-heat boilers for the Nos. 2 and 3 smelting units at the McGill plant of the Nevada Consolidated Copper Corporation are shown in Fig. 1. Each of the two reverberatory furnaces has its own set of waste-heat boilers, and before February, 1932, each furnace, when it was in operation, delivered waste-heat gases to its own boilers only. In January, 1933, the idea was suggested of using some of the waste-heat boilers as economizers to operate in conjunction with the waste-heat boilers that were generating steam. The execution of this idea gave rise to the gas-flow scheme depicted in Fig. 1, the advantages of which were obvious, particularly so in view of the fact that for some months prior to the adoption of this scheme the smelting had been confined to No. 2 furnace, with No. 3 furnace and its boilers idle. The waste-heat gases from No. 2 furnace pass through the boilers serving this furnace as steam-generating units, thence through the original exit duct to a point where a bulkhead diverts the gases in a reverse direction through two of the boilers of No. 3 furnace. After the gases have traversed these two boilers, another bulkhead placed in the duct between No. 3 furnace and its boilers causes them to traverse still one more boiler, from which the gas path leads to the stack. In this scheme the last three boilers traversed by the gases, i.e., the boilers behind No. 3 furnace, function as economizers and preheat the feed water for the two steam-generating units directly serving No. 2 furnace. This discussion will give consideration to the results obtained in waste-heat recovery by the scheme shown in Fig. 1, and, further, will compare these results with those obtained before the boilers of No. 3 furnace were set up to act as economizers, but before going into the detail of heat generation, distribution and recovery, will present some additional details of the equipment. All boilers in this waste-heat plant are of the Stirling type. The two behind No. 2 furnace, acting as steam-generating units, of class 13, are 40 tubes wide and rated at 1112 boiler hp., while the three boilers behind No. 3 furnace, acting as economizers, are also of class 13, but 28 tubes

Jan 1, 1934

By Earl Oliver

Superficial observation of the petroleum stabilization movement in 1932 is disappointing. Threatened overproduction persisted; waste continued; proration was violated; gasoline taxes were evaded; and, as a consequence, chaos threatened the industry as the year drew to a close. However, comparison of the movement in 1932 with its beginning a few years ago, and analyses of those influences that promote its growth as well as those which retard it, disclose some reasons for encouragement. Stabilization, as we see it, is not merely a mechanical engineering problem. It involves social engineering. By which we do not mean it is possible, or even desirable, to change the nature of men, but rather that it is possible to set up procedure that will avoid causing them to clash. It comprehends consideration of physical objects that is clearly within the field of the engineer, but it considers them only in relation to their distribution, utilization and control in harmony with philosophies that motivate men and shape current conceptions of right and wrong, or of justice and injustice if those terms be deemed more acceptable. Stabilization cannot be effected without utilizing the knowledge of the engineer, but neither can it be effected without utilizing more than comes within his traditional field of activity. In discussing the problem herein we shall endeavor to treat it briefly from that consolidated viewpoint. Rapid fluctuations in supply have characterized the oil industry from its beginning; yet only within the past ten years has an understanding begun to develop regarding the extent of waste—the degree of dissipation of natural resources—that attends the operation of the industry under the practices and laws which control it in the United States. The extent and regrettable consequences of those wastes, their underlying causes and the ease with which they could be prevented are not yet generally understood even within the industry. Producing TomoRRow' s Oil Today The interests detrimentally affected by these economic evils are vastly greater than the mere welfare of the oil industry. The problem involves the nation's supply of gasoline and other petroleum products at

Jan 1, 1933

By G. W. Traer

The distillation of bituminous coals at what is commonly termed low temperature, and the quantities, nature and adaptabilities of the products have been the subject of considerable experimentation, during recent years. Fortunately, the earlier work in this country was done by men whose scientific training qualified them properly to record and interpret the results of their experiments. The work of Prof. Parr, of the University of Illinois, is especially notable in this respect. Prof. Parr's work, added to that of English experimenters, demon-strated-certain things to a degree which is generally regarded as convincing. They have proved that a caking bituminous coal, when subjected to a temperature of not more than 1000" F. (preferably somewhat less) will yield light tar having low specific gravity (about 1.06) and high value; also, that this yield, with a given coal, will depend upon the percentage of hydrocarbons in the coal, the maximum temperature used, and the promptness with which the distillate gases are removed. It is assumed that air is excluded from the retort, and that the coal is subjected to heat for a sufficient time to drive off all of the tarry hydrocarbons. The results attained in the first, or low-temperature stage of the car-bocoal process, recently described by C. T. Malcolmson,1 corroborate these general principles. It is the purpose of the writer to describe other work of a practical nature, directed toward the commercial adaptation of these principles, which was begun nearly two years ago; this investigation was assisted by A. J. Sayers, of the Link-Belt Co., and Carl Scholz. The first step was to draft tentative designs for the handling of the coal and coke so as to produce a coke having a suitable structure for sizing, storage, shipment, and handling, without the necessity of briquetting. Prof. Parr's results had indicated that the rather open-pored volatile coke produced by him had a low ignition point, which would contribute toward easy control of the fire in stoves, house furnaces, fire-boxes, and boilers. It is recognized by those experienced in the marketing of fuels that the hard non-volatile coke from the high-temperature process,

Jan 1, 1920

By Dell H. Adams

COAL EXPLORATION Coal exploration may be defined as the acquisition of data necessary to define and acquire a block of coal which can be mined at a profit. Unlike ore minerals, coal resources are widespread and relatively abundant with supply exceeding demand in almost every case. Thus simple discovery of coal is generally not enough. The chemical and physical variability of individual coal seams, the capital intensive nature of coal mine development, and the changing patterns of utilization require that a multiphase, three-dimensional evaluation be made of each potential reserve. Factors which must be investigated include not only the quantity and quality of the coal but also the geologic, hydrologic, and engineering characteristics of the seam and its surrounding strata. Acquisition of property to provide a secure base for exploration and mine development is equal in importance to the geologic and engineering programs. The successful development of a coal reserve requires that control of coal and, in the case of a strip mine, the surface be in the form of contiguous blocks of sufficient size to support mining. PHASES OF EXPLORATION The high capital risks of coal exploration and land acquisition dictate that a multiphase program be utilized to minimize initial risk. In such a program, phased development of the data insures that each increase in capital expenditures will be justified by a corresponding increase in the level of confidence in the ultimate success of the project. Each phase is designed to provide sufficient data and property control to facilitate the decision whether to proceed to the next phase of development or to discontinue the program (Table 1). The first phase of a typical exploration program consists of a pre-

Jan 1, 1981

By Peter G. Tregelles, Derek K. Barham

Introduction A successful step towards mechanisation of the collier's work was taken in 1954 when the first Anderton shearer loader was commissioned in Lancashire, and progress was reinforced in 1956 when the first powered supports were installed in Nottinghamshire. By 1970, virtually 100% of the coalfaces in the United Kingdom were mechanised and the industry's productivity had doubled. In 1961 the National Coal Board recognised that the next move towards greater productivity and improved safety would be to automate the longwall system. What was not well enough understood, however, was that the basic prerequisites of automation - reliability and measurement - had not yet been achieved. Consequently, the schemes for automatic longwall faces and for an entirely automated colliery were abandoned at the close of the decade. A review of mining research and development policy, commissioned by the Board in 1974, confirmed that the system of longwall mining had great potential for investment and that the short-term policy of automation must once again be pursued. Since then, aided by advances in computer technology, systems for automating the transport of coal from the face to the coal preparation plant have been successfully instituted. Applications of sub-systems dealing with the conveyor, coal preparation plant, and various items of fixed plant are now at the exploitation stage. In the medium term, a number of key problems have been identified, which will arise once the productivity from the coalfaces has doubled, as it is now expected to do in the next five years. One of the most important of these problems is machine guidance, and considerable research and development work is now being carried out in this area. This paper reviews the work on machine guidance prior to 1974 and explains the programme on which the National Coal Board's Mining Research and Development Establishment is currently working.

Jan 1, 1981

By Arthur Zentner

The electrolytic zinc plant of today is foreshadowed in the patents issued to Léon Létrange of Paris in 1881 and 1883l. He proposed roasting zinc blende to make the zinc soluble in water or sulphuric acid, thus obtaining a sulphate solution. His purification was apparently that used in the lithopone work of the day. For electrolyzing he proposed anodes of carbon or lead, for cathodes zinc, copper or brass. Numerous patents by other workers were taken out in the first 10 years, most of which dealt with sulphate solutions. It is easy to presume that the formation of chlorine gas in zinc chloride electrolysis caused early emphasis on sulphate work. Lack of success with this invited further work with chloride solutions. Efficient and cheaper oxidizing agents for use in the chloride processes were more generally available. Carbon anodes could be used instead of lead anodes, which were blamed for much of the early electrolyzing troubles and remained in disfavor for many years. Carl Hoepfner received his first zinc patents in 18902. He was the most persistent of those who worked with chloride solutions and met with the largest measure of success. Hc built three plants, only one of which remained in operation. This was built in 1896 at the plant of Brunner, Mond & Co., Winnington, England, now part of Imperial Chemical Industries Ltd. It leached with by-product calcium chloride from the company's Solvay alkali plant and returned to it the chlorine formed in electrolyzing. The zinc plant had a capacity of 5 long tons of zinc, said to have been doubled later, and remained in operation until 1924. No commercial plant using chloride solutions has operated since then. E. A. Ashcroft experimented in the middle nineties with chloride, alkaline and sulphate solutions on materials from Broken Hill, Australia. He built a plant with a rated capacity of 10 long tons of zinc per day, at Cockle Creek, New South Wales, in 1898. This figure was never approached nor was cyclical operation achieved. The work in the plant appears to have been largely with sulphate solutions. The plant suffered from a multitude of troubles: poor roasting, gclatinous silica, liberal use of live steam in solutions to combat the gclatinous silica with considerable

Jan 1, 1937

AT a luncheon attended by engineering leaders representing every section of the country, Col. Arthur S. Dwight, president of the American Institute of Mining and Metallurgical Engineers, and Charles F. Rand, chairman of the Engineering Foundation, past president of the Insti-tute and its present treasurer, on Thursday, July 20, were decorated with the Croix de Chevalier de la Legion d'Honneur by the French Government for distinguished service in engineering tending to closer and more felici-tous relations between the two countries. The decorations were conferred by Consul General Gaston Liebert. In a speech extolling the war work of the American engineer, M. Liebert declared that Germany had been definitely foiled in her attempt to cripple France industrially for a generation by wrecking the coal mines of northern France. Three-fourths of these mines, M. Liebert said, were in full working order and the remainder will be in complete operation within two years. The Germans thought that it would take from 15 to 20 years to accomplish this. M. Liebert said that reconstruction is going on rapidly in northern France, two-thirds of whose indus-tries are now working. The French Government, he said, is planning water-power improvement on a vast scale, which will soon make unnecessary for France to import a single ton of coal. He urged that French students be sent to America to study engineering. In presenting the decorations, Consul General Liebert eulogized Colonel Dwight and Mr. Rand as personify-ing the spirit and service of the American engineer, which, he said, was a powerful factor in the victory over Germany. He spoke of the growing friendliness between the United States and France and described this ceremony as an epoch in international relations. Calvin W. Rice, secretary of the American Society of Mechanical Engineers, who presided, repeated that international unity among engineers was the dream of Andrew Carnegie, who saw in the efforts of the engineer and the scientist the hope of civilization. Mr. Rice said in part: In the Declaration of Independence occurs the statement that all men are created free and equal. Jefferson was familiar with the writings of Rousseau. In fact, he was a remarkable linguist notwithstanding that he wrote the Declaration of Independence when only 32 years of age. He was one of the very few ambassa-dors in the history of the United States who could speak the language of the country to which they were sent. The interpretation of the passage in the Declaration of Independence is that all men have equal opportunity, not that they are born with equal ability.

Jan 8, 1922

By L. S. Reid, R. L. Hunntington

The study of the flow of oil and gas mixtures through oil-bearing formations has received special attention from the petroleum industry within the past few years, and has resulted in a series of research projects based upon various phases of the flow of heterogeneous fluids through porous media. Obviously, the low cost of producing oil during the flowing life of a well makes it desirable to obtain production by natural flow as long as possible and to effect a maximum recovery of oil and gas by the utilization of reservoir energy through efficient methods based upon a thorough knowledge of reservoir characteristics. Despite the extensive research that has been carried out, there is little information available on the behavior of oil and gas mixtures flowing through reservoir formations. This makes it impossible to predetermine the optimum operating conditions for flowing wells. A differential pressure must exist in the reservoir in order to induce flow toward the well. It is a well established fact that with homogeneous fluids the relation of pressure drop to linear distance traveled is a straight-line function as long as the flow is viscous. However, in regard to gas-saturated oils, a number of investigators1l,2,3 have reported that the flow characteristics are materially altered as some of the lighter hydrocarbons are liberated from the oil to form gas while the fluid passes through the reservoir. Most of the work done has been concerned primarily with steady-state flow of liquid-gas mixtures. Cloud1 has studied the effects of saturating crude petroleum oils with various gases, together with the resultant pressure gradients under steady flow conditions, noting that unsaturated oils flowed faster and yet maintained lower pressure gradients than saturated oils. The work of Wyckoff and Botset4 has constituted a major step in the interpretation of heterogeneous fluid flow; especially their concept of

Jan 1, 1938

By Allen D. Garrison

THE chemistry of clays and shales has been assuming increasing importance in the petroleum industry, and two factors have greatly influenced this trend. The first has been the growing evidence that the marine shales are source beds, and that the petroleum compounds have migrated to the sand reservoirs overlying or underlying these shales: the second has been the demand for drilling fluids better adapted to penetrate these marine shales without difficulty and expense. ORIGIN AND GENERAL COMPOSITON OF CLAYS AND SHALES Clays, shales and surface soils are all closely related materials. They are mixtures of finely divided compounds formed during the weathering of the solid crust of the earth. Their nature is essentially colloidal; that is, their behavior is determined by the state of division of the materials and the surface reactions of the smallest grains. Many of their chemical changes affect only the exposed areas and do not involve the interior of the grains of matter. The extent of these reactions is more nearly proportional to the area of the substances than to their mass, therefore it is possible for a small amount of a material in an extremely fine state of division to completely dominate the character of the mixture. More than 83 per cent of the crust of the earth is composed of three elements-oxygen, silicon and aluminum. Consequently, the corrosion products of the crust are predominantly aluminosilicates, or compounds of aluminum, silicon and oxygen. If we add the compounds of six elements-iron, calcium, sodium, potassium, magnesium and hydrogen-more than 98 per cent of the crust has been accounted for. These six elements, together with the first three, also appear in soils, clays and shales. But direct chemical analysis is of little value in describing the nature of such materials. Many chemical individuals may be present in variable amounts, and the extreme subdivision of any one of the individuals may contribute qualities that dominate the mixture.

Jan 1, 1939

By Alexander L. Holley

THE Pernot system of rotating and withdrawing the hearth of a Siemens regenerative gas furnace for the production of Martin or open-hearth steel, is, perhaps, the most conspicuous of the several improvements which have lately been made in the steel manufacture. These several improvements in the open-hearth plant are not combined in any existing works, but most of them will be combined in not less than three works now erecting in the United States; and it seems probable that their joint result will not only reduce the cost of products of ordinary grades to Bessemer rates, but that it will produce new and better grades of products. The open-hearth steel furnace and its operation are so generally understood that but a few words of general description are necessary. The ordinary furnace is not unlike the common reverberatory puddling furnace, except that an intense, uniform, and controllable temperature is maintained by the Siemens gas regenerative system. The materials. employed are various : melted or unmelted pig with ore, and with or without scrap; pig iron purified from silicon and phosphorus, with or without scrap; pig iron and scrap, melted together in a cupola, or charged hot or cold, together or separately, into the steel furnace; a pig-iron bath, and hot or cold steel or iron scrap, direct sponge or Catalan or puddled blooms charged into the bath. The operation is, to a greater or less extent, according to the nature of the materials used, a desiliconization and decarburization of the pig or other crude iron, and its dilution by already purified materials. Manganese is employed at the end of the operation to remove oxide of iron and silica, a regulated amount of manganese remaining in the product. Figs. 2 and 3, Plate IV, represent the hearth and roof of the Pernot furnace; Fig. 1 shows, in cross section, the general arrangeent of open-hearth plant with Pernot furnaces, as generally designed by the author, and now building at two works. The engrav-

Jan 1, 1879

By Emile Gyss

THE speed of drilling rock has become an impor-tant factor in mining operations, while the place-ment of holes, kind, and quantity of explosive used. are equally important. These are a function of the rock hardness and toughness. Both of these fac-tors must be considered in compiling a table that will enable a mine operator or engineer to estimate drilling speeds in a given rock, knowing its hardness, and from its toughness, the dynamite required. The hardness of a homogeneous rock may be defined as its resistance to a penetrating medium, such as a drill-steel bit, and toughness, its resistance to with-stand rupture by the tearing apart of its minerals or parts of the same mineral. Rock hardness, as it has here been defined, is a function of the hardness of the component grains composing it, as well as grain size, shape, arrangement, and binding minerals. Rock tough-ness depends on substantially the same factors, but is measured by a totally different method. The units in which rock hardness is usually ex-pressed are either relative values or alphabetical desig-nations which carry no definite quantitative meaning. R. M. Raymond has suggested the measurement of com-posite rock hardness, based on mineral hardness as ob-tained by the Moh scale. This is done by multiplying the percentage of each mineral in a rock by the Moh mineral hardness and dividing by 100. These values convey a clearer conception in the minds of men in-terested in rock work -and are the basis of the units used in Tables 1 and 2. The hardness of rocks as it has been variously de-fined may be determined by different methods. The first method is one in which the proportionate average of the hardness of minerals making up a rock is the basis for classification. The other factors of grain size, shape, arrangement, and binding power are not considered.

Jan 6, 1927

By C. V. Millikan

New developments in air-gas lift practices in the Mid-Continent area since our Pall meeting in Fort Worth have done much to increase the efficiency of installations, and thus bring within economic limit of air-gas lift many wells which could not have been flowed profitably before. After the gas-lift had so thoroughly demonstrated its value in the Seminole field, its use spread to other areas and many installations were made of which the economy could be questioned. In the Seminole area, when production began to decline it was necessary either to increase the efficiency of the air or gas-lift or to put the wells on the pump, and pumping was not a process of lifting oil to which any operator looked forward with confidence. These conditions have resulted in the development of many practices which increase the efficiency and permit wells to be flowed with air or gas which earlier could not have been flowed economically, and wells which have been flowing to continue to a lower rate of production. The practices which have come into more common usage in the Mid-Continent area recently are mostly revivals of and improvements on practices which have been known in air-lift work for several years. Many arc peculiar to the individual well on which they are used. Intermittent Flowing Some interesting results are being obtained in Seminole and other districts by intermittent injection of gas. Gas is introduced during per-iods iods of 3 to 5 min. at a rate considerably over that necessary to acquire the production at a steady rate of injection, and is then cut off for a period of 3 to 15 min. Two to five wells are run from the same group of conlpressors. The total volume of gas required is sometimes reduced as much as one-third of that required when it is introduced at a constant rate, without changing the amount of oil production. The maximum pressure required is usually higher, but the average equal to or lower than that required for constant rate of flow. The effect on the wells is usually an irregular rate of flowing which may cause inconvenience where recycling is practiced. It would seem that this increase in efficiency is due to less slippage when the gas is introduced intermittently than when it is intro-

Jan 1, 1928

By R. L. Wiegel

This article proposes a physical model for an idealized binary mineral system and for the process of liberation by size reduction. Based on this model, equations are derived relating the amount of each component liberated as a function of the ratio of the volumetric abundance of the two mineral components and the ratio of the mineral grain size to particle size. A definite relationship is shown to exist between the mineral concentration within a locked particle and the frequency of occurrence of such a particle. These relationships are used to obtain theoretical expressions for the concentration-recovery diagram. Physical mineral beneficiation processes are based on breaking a mineral aggregate to liberate the dissimilar mineral grains and then making use of their physical properties to separate the mixture into its components. The effectiveness of the process is therefore dependent on how well the minerals are liberated and how efficiently they are separated. Although a substantial amount of work is being done to improve our understanding of mineral separation processes, the study of mineral liberation itself has been almost completely neglected. The purpose of this theoretical study is to shed some light on the liberation phenomenon by: 1) proposing a physical model for an ideal binary mineral system, 2) treating mathematically the fracture of this system into liberated and locked particles, and 3) deriving an expression for the liberation characteristics of this system. The results of this study are useful in understanding the effect and importance of various parameters in liberation, and provide a basis for comparison with real mineral systems. 'RANDOM' MODEL It is recognized that liberation can be caused by detachment which results from fractures occurring at the mineral grain boundaries, or by size reduction which restricts the occurrence of dissimilar mineral locking to a portion of the resulting particles. The detachment effect is dependent on the relative strengths of the mineral grains and the bonds between them, and must be treated empirically for each mineral system. The size reduction effect, however, can be treated analytically if certain assumptions are made concerning the shape and geometrical arrangement of the mineral grains.

Jan 1, 1968