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By Emby Kaye

IT is the purpose of this paper to outline briefly some of the considerations that enter into the economics of so-called recycling, the generic designation of the relatively recently developed process by which a condensate† is separated from gas-distillate gas at high pressure and the residual gas returned to the reservoir. This subject necessarily embraces not only a discussion of factors that should be considered in projecting a recycling operation, such as estimating reserves, investment and operating costs, but also a comparison of condensate with other types of petroleum. The place of condensate in its relation to the total supply of crude oil is pointed out as well as certain logical methods of product disposal. The cost of drilling wells and lease maintenance is not pertinent to this discussion because income and revenue are in this paper confined to that retained by the plant or plant operator for supplying processing facilities for the gas. Before the development of recycling a great many gas-distillate gas fields in Louisiana and. Texas provided no income to their owners. When gas was sold from these reservoirs it was accompanied by irretrievable losses of condensate in the formation. The understanding of the function of retrograde condensation resulted in the introduction of a new commercial petroleum recovery process for these hitherto unexploited fields and now permits the conditioning of this type of wet gas field for the sale of dry gas therefrom without waste. SOME ECONOMIC FACTORS The study of a gas-distillate field for possible exploitation necessarily involves the critical appraisal of a number of elements, chief of which will be discussed here: (I) estimate of distillate in place, (2) estimate of distillate that can be brought to the surface, (3) available market, (4) costs. The considerations affecting the estimating of distillate reserves. in place are in the main subject to the same errors as are involved in determining dry gas reserves. Determinable data including acreage, sand thickness, reservoir pressure, reservoir temperature, porosity and connate water provide the basis for calculating the volume of gas in place. Ample allowance must be made for connate water, which may occupy from 20 to 35 per cent of the pore space of the sand. The factor of supercompressibility is to a considerable extent nullified by the reservoir temperature. It has been considered well advised to allow this factor to serve as a cushion. With the gas reserves calculated, it remains only to assay the distillate content of the gas. Those familiar with the handling of "wet" gas at high pressure readily appreciate the variables in sampling gas from

Jan 1, 1941

Officers of the Institute have been entertained by, members at nine meetings in different parts of the country during the months of March and April. Institute policies have been discussed by the officers and by members present at the different meetings, with the result of bringing about a better understanding of Institute policy among the members; it has also been made clear how various suggestions are viewed by members who are not all in close touch with Institute activities and with the policy of the Board of Directors. President Jennings devoted his remarks chiefly to an account of Institute activities in connection with Government service for the war, and presented an able address on the relations of labor and capital; with special relation to possible changes that may be necessary during the reconstruction period following the war. This carries forward the suggestion made by him in taking up the reins of government at the Annual Dinner on February 20, 1918, and makes available a paper which has aroused great interest at the different meetings; this address will be found on a following page. In referring to Institute activities in connection with the war, the President mentioned especially the Naval Consulting Board, the War Committee of Technical Societies, the War Minerals Committee, and the census of engineers prepared not only by the Institute in connection with the Bureau of Mines, but also by the American Society of Civil Engineers, the American Society of Mechanical Engineers and the American Institute of Electrical Engineers. He announced also the appointment of two committees, one on ferrous and one on non-ferrous metals, advisory to the Tariff Commission, and the appointment of a member of the Committee on the Excess Profit Tax, having especially to do with the question of excess profit taxes on gold mines. He also announced the appointment of a new committee known as the Committee on Industrial Organization, which will devote its energies largely to the question of relations of capital and labor and of "human engineering."

Jan 5, 1918

By Theron Wasson

The year 1942 in Michigan was devoted largely to the development of fields discovered in 1941 but was also characterized by a great increase in prospecting for new productive horizons below the Dundee limestone. Some new fields were discovered but as yet these have shown few signs of being of major importance. Michigan's total production for 1942, of 21,754,000 bbl. of oil, as reported by the U. S. Bureau of Mines, was second only to the record year of 1939 when 22,799,000 bbl. of oil were produced. All important fields were prorated throughout the year, and it is obvious that without proration a new all-time high would have been established for the state this year. From 1925 to the end of 1942, Michigan has produced annually the following amounts of oil: Year Barrels Source 1925 4,000 1926 94,000 1927 435,000 1928 592,000 1929 4,641,000 1929 Michigan Geological Survey 1930 3,928,000 3,785,000 1932 6,925,000 1933 7,942,000 1934 0,603,000 1935 15,776,000 U.S. Bur. Mines, 1937 1936 11,928,000 U.S. Bur. Mines, 1938 1937 16,628,000 U.S. Bur. Mines, 1939 1938 19,211,000 U.S. Bur. Mines, 1938 1939 22,799,000 1940 19,764,000 1941 16,361,000 1942 21,754,000 Total 183,170,000 This tabulation shows the steady growth of the industry in Michigan since the first discovery of oil in 1925. Maes A map of the oil and gas fields of Michigan in 1941, published in the report for 1942, shows the main producing areas and should be referred to if information in regard to their location is desired.* The main producing zones were shown in the columnar section in the same publication. Development in Fields Reed City Field.—During 1942 the Reed City field, which ended 1941 with 112 producing oil wells, added 70 new producers to bring the total at the end of the year to 182 wells and 4700 proven acres. A south extension of the field developed during the year was in large part responsible for the increase. Approximately 9,000,000 bbl. of oil was produced from the field during the year, bringing the total accumulated production to the end of the year to roughly 11,750,000 barrels. Headquarters Field.—The Headquarters field, which started the year with ro producing oil wells, ended the year with 41 wells aid 1240 proven acres. Approximately 2,300,000 bbl. of oil was produced in 1942. Kawkawlin Field.—Although not a 1941 discovery, the Kawkawlin field has been actively developed on the 40-acre spacing plan during the last year, 42 producers having been completed, bringing the total number of wells at the end of the year to 77. Nearly 500,000 bbl. of oil was produced during the year.

Jan 1, 1943

By Theron Wasson

The year 1942 in Michigan was devoted largely to the development of fields discovered in 1941 but was also characterized by a great increase in prospecting for new productive horizons below the Dundee limestone. Some new fields were discovered but as yet these have shown few signs of being of major importance. Michigan's total production for 1942, of 21,754,000 bbl. of oil, as reported by the U. S. Bureau of Mines, was second only to the record year of 1939 when 22,799,000 bbl. of oil were produced. All important fields were prorated throughout the year, and it is obvious that without proration a new all-time high would have been established for the state this year. From 1925 to the end of 1942, Michigan has produced annually the following amounts of oil: Year Barrels Source 1925 4,000 1926 94,000 1927 435,000 1928 592,000 1929 4,641,000 1929 Michigan Geological Survey 1930 3,928,000 3,785,000 1932 6,925,000 1933 7,942,000 1934 0,603,000 1935 15,776,000 U.S. Bur. Mines, 1937 1936 11,928,000 U.S. Bur. Mines, 1938 1937 16,628,000 U.S. Bur. Mines, 1939 1938 19,211,000 U.S. Bur. Mines, 1938 1939 22,799,000 1940 19,764,000 1941 16,361,000 1942 21,754,000 Total 183,170,000 This tabulation shows the steady growth of the industry in Michigan since the first discovery of oil in 1925. Maes A map of the oil and gas fields of Michigan in 1941, published in the report for 1942, shows the main producing areas and should be referred to if information in regard to their location is desired.* The main producing zones were shown in the columnar section in the same publication. Development in Fields Reed City Field.—During 1942 the Reed City field, which ended 1941 with 112 producing oil wells, added 70 new producers to bring the total at the end of the year to 182 wells and 4700 proven acres. A south extension of the field developed during the year was in large part responsible for the increase. Approximately 9,000,000 bbl. of oil was produced from the field during the year, bringing the total accumulated production to the end of the year to roughly 11,750,000 barrels. Headquarters Field.—The Headquarters field, which started the year with ro producing oil wells, ended the year with 41 wells aid 1240 proven acres. Approximately 2,300,000 bbl. of oil was produced in 1942. Kawkawlin Field.—Although not a 1941 discovery, the Kawkawlin field has been actively developed on the 40-acre spacing plan during the last year, 42 producers having been completed, bringing the total number of wells at the end of the year to 77. Nearly 500,000 bbl. of oil was produced during the year.

Jan 1, 1943

By W. McA. Johnson

The work of J. E. Johnson, Jr., on the effect of small amounts of oxygen in cast iron in increasing its strength and resistance to shock, is of interest from the technical and scientific standpoints. The following exposition of the theory carries Mr. Johnson's explanation further and, in my opinion, will disclose certain related phenomena and perhaps shed further light on the subject. Some facts, so novel in character as to excite incredulity, have been accepted finally by many metallurgical authorities. One of these is that oxygen to the amount of 0.060 per cent. in cast iron gives it a breaking strength of 3,500 Ib. per square inch, compared with a breaking strength of 2,500 lb. per square inch in cast iron of the same composition with respect to elements other than oxygen, but having only 0.010 per cent, oxygen. The "oxygenated" cast iron, even if made in a coke furnace, has properties equivalent to the best charcoal pig iron. Mr. Johnson has also established the fact that the variations in combined carbon cannot account for the results. By microphotographic evidence he has shown that in oxygenated cast iron the graphite particles are dense and spherical, while in well-deoxidized cast iron the graphite particles are flaky and leaf-like. It is just a matter of common sense that iron of the latter structure is much weaker than the former. The analytical and microscopical work has been done with care and there is no doubt in my mind about the accuracy of the experimental results. In this paper then, we shall consider it as accepted that small amounts (0.060 per cent.) of oxygen increase the strength of cast iron by producing a structure in which the round and solid particles of graphite are surrounded firmly by a principal matrix of ferrite. The purpose of this paper is to show that the reason why the graphite particles are round is founded on the fact that the particles of any precipitate are made denser and harder by the presence of a reagent having a solvent action on the precipitate. This can be stated as a law, although I have never seen it so given in any textbook. Let us then, for purposes of illustration, give a concrete example and develop the theory of such mechanical and chemical actions as occur: It is well known that, by a soluble sulphate, a barium salt in solution is precipitated in a dense and easily filtered body when the solution is

Jan 1, 1916

By S. Parker Gay

In 1967 Southern. Peru Copper Corp. was faced with the problem of developing a water supply for their new Cuajone open-pit copper mining and milling operation, at a time when the existing water system was inadequate for a proposed expansion of the producing Toquepala mine. The most probable source for additional water was considered to be the Pasto Grande basin lying 30 km north of the terminus of the pipeline. This source of supply could be developed only at substantial cost, after construction of a dam, tunnels, pumping plants, and several miles of canals. Investigation of other possible sources was undertaken, and one of these was the Huaitire alluvial fan which had been recognized on aerial photographs in 1961. Resistivity soundings on the fan provided isopach information for estimating the volume of fan sediments. In the course of carrying out these soundings, a high-resistivity layer at depth was indicated. The favored geological interpretation of this layer at the time was a tight impermeable volcanic formation, but an alternative explanation was a ground-water aquifer of high transmissibility. Geological studies just released by the Peruvian Geological Map Commission supported the latter interpretation. A diamond drill hole sunk to a depth of 725 ft on the Huaitire Pampa in June 1967 proved the absence of the expected volcanics, the presence of the sediments, and indicated that some sedimentary horizons carried artesian water. Subsequent well drilling and hydrological and geological studies show that the aquifer occurs principally in the Upper Tertiary Capillune formation, covers an extensive area on the Peruvian altiplano, discharges enormous quantities of water to a large number of canyons dissecting it, and will adequately supply most, if not all, water needs of the Cuajone operations.

Jan 1, 1973

It is always the case with heavy and cheap materials that the area within which they can be economically used depends upon the cost of transportation, and in those days of poor roads and no mechanical means of haulage on them, coal could only be moved a few miles from the mine by any other means than water. The need of better means of transport to the areas west of the mountains had been urged by Washington and many other leaders, but the first turnpike over the Alleghenies only reached the Ohio River at Wheeling, W. Va. in 1818. The James River and Kanawha road reached the Ohio in 1831, that from Winchester, Va. to Parkersburg in 1838, and the road through the Cumberland Gap was completed in 1797. None of these affected the coal industry excepting indirectly by building up some of the river towns which coal could reach. The inadequacy of roads alone to carry the traffic of the rapidly growing interior communities was demonstrated only a few years after the National Pike was completed, and in the early 1820's several of the states embarked upon the construction of a canal system, which had been under discussion for some years. The Erie Canal was opened in 1825 from Lake Erie to the Hudson River through New York; Pennsylvania, Virginia and Maryland had already started similar projects designed to bring traffic to their principal cities from the interior. The Pennsylvania Canal was started from Columbia, as a railroad extended from Philadelphia to that point, and it followed the Susquehanna and Juniata Rivers to Hollidaysburg; thence to Johnstown, a distance of 36 miles, where it consisted of partly railroad and partly inclined planes, the boats being hauled up, and lowered down the planes; from Johnstown the canal followed the Conemaugh, Kiskiminitas and Allegheny Rivers to Pittsburgh, 104 miles. Boats first reached Pittsburgh by this route in 1834. The Chesapeake and Potomac Canal followed the Potomac River from a point above Alexandria above the falls, to Cumberland. This canal was chartered in the eighteenth century and a portion of it was used by traffic in 1800. It was too small to be of much use and was abandoned, and later after many legal and financial vicissitudes was completed to Cumberland, traffic from there starting late in 1850. This date, however, was long after the Baltimore and Ohio Railroad had been completed to

Jan 1, 1942

By R. L. Schmidt, J. D. Verhoeven

The diffusion coefficients and electrotralzsport mobilities of aluminum, gallium, and arsenic have been determined in molten germanium with the capillary reservoir technique. The diffusion coefficients are slightly higher than those determined by the solidification technique of Brirton et a1.1 It was found that aluminium and gallium migrate to the cathode in molten germanium) whereas arsenic migrates to the anode under an electric field. A possible technique for producing p-n junctions by means of electric field freezing is discussed in view of the experimental data. In the past decade or so the literature has abounded with articles concerning the solid-state properties of the semiconducting elements germanium and silicon. It is surprising by comparison how little has been published concerning the liquid-state properties of these materials. In the production of doped germanium or silicon the diffusion coefficient of the dopant in liquid germanium or silicon is an important quantity. Yet, to the best of our knowledge, no one has ever made a direct measurement of the diffusion coefficient of solutes in either molten germanium or silicon. A number of authors'-4 have determined some diffusion coefficients by the indirect technique developed by Burton et al.1 This technique appears to give numbers of the correct order of magnitude but it does depend upon a number of assumptions in the analysis and also requires prior knowledge of the viscosity of the melt. In the present work a more direct measure of the diffusion coefficients of arsenic, gallium: and aluminum in molten germanium has been made. It has been shown independently by two groups of authors5, 6 that, when an electric current is passed through the interface of a solidifying metal containing an impurity, the resulting electrotransport in the liquid boundary layer at the interface offers a mechanism for control over the redistribution of the impurity accompanying the solidification. These authors show that the degree of control is proportional to the mobility, U of the impurity atoms in the liquid boundary layer, where the mobility is defined as the drift velocity relative to the solvent per unit electric field. In principle the results apply to the solidification of a doped semiconductor and offer an interesting technique for control of the doping of a semiconductor. In the present work the mobilities of aluminum, gallium, and arsenic were determined in molten germanium in order to evaluate the potential usefulness of electro-transport as a technique for solute control when applied to the solidification of doped germanium. EXPERIMENTAL PROCEDURE Both the diffusion coefficients and the mobilities were measured using high-purity alumina capillaries and a resistivity technique for analysis. A schematic diagram of the electrotransport apparatus is shown in Fig. 1 and the details of the cell design are shown in Fig. 2. For the mobility experiments electrical contact with the bottom of the capillary was made with graphite, as shown in Fig. 2. In order to prevent electrical contact with the melt the graphite was coated with a thin layer of alumina using a plasma spray torch. The cell assembly, a graphite electrode, and another assembly containing two blank capillaries were fastened to the lavite disk shown in Fig. 1. To make a run the system was evacuated and the doped germanium was outgassed at the operating temperature of 1030°C. The cell and blank capillaries were then submerged beneath the melt and a slightly positive pressure of helium was introduced to fill them. After passing current through the cell for a given time the cell and blank capillaries were raised from the melt and the furnace was shut off. The temperature of the cells dropped below the freezing point of germanium within 1 to 2 min after the furnace was shut off.

Jan 1, 1968

By Sinha D. K.

As the main source of indigineous energy, coal has a big role to play in the development of national economy of India. Nationalization of the coal mining has brought the entire industry under the unit control of the Central Government following which an ambitious plan for increasing the coal production in the next few five year plans has been undertaken. In order to achieve best all round results, economy-mathematical models of Planning the total system, right from the highest to lowest hierarchial levels of decision making, have been proposed through a Global Model which is detailed in Local Models in stages right up to a mine. Optimum obtained by computer solution of the models would provide basis for objective decision making in the fields of selection of optimum plan for developing the industry, the coal fields and the mines with construction and/or reconstruction of mines, capacity optimization of enterprises and mines therein. Different types of Models and the optimization processes are presented.

Jan 1, 1977

By Kendall E. Born

Production of crude oil in Tennessee during 1941 was slightly more than 15,000 bbl., about the same as in the preceding year. Two thirds of the total was from the Mississippi limestone pools in Scott and Morgan Counties. About a dozen small scattered wells in Clay, Pickett, and Fentress Counties, pumped irregularly, produced approximately 5000 bbl. Natural gas was marketed from wells in Morgan and Fentress Counties for consumption in the Sunbright and Jamestown areas, respectively. The production by counties is shown in Table I. Drilling activities in the state fell to the lowest stage since 1933. Twenty-seven wells were spudded in during 1941, of which six were drilling or only temporarily suspended on Dec. 37, 1941. Of the 22 completions, four were gas wells of undetermined quantity, but are classed as commercial, and 17 were dry or near-dry holes. One well encountered oil, but it has not been tested. The total footage drilled during the year was 29,916 ft.; the average depth of wells was 1359 ft. The more important wildcats are listed in Table 2; the distribution of tests according to physiographic divisions is given in Table 3. East Tennessee.—One well was drilled to 3480 ft. in northwestern Anderson County, in the highly disturbed Appalachian area, a region long considered the most unfavorable in the state for the accumulation of oil and gas. Another test is now drilling below 2000 ft. in this general area. Cumberland Plateau.—There were two completions in the Cumberland Plateau area. One test, drilled in northwestern Scott County in an area of former Mississippi limestone production,' encountered a considerable amount of free oil at 850 ft., about the same horizon as in the old abandoned wells. No pumping tests have been made to date. A well at Oneida, Scott County, found gas at 1579 ft. in a sandy limestone of lower Mississippian age. The volume was reported doubled by a shot, although no open-flow measurement is available. Eastern Highland Rim.—Six completions on the eastern Highland Rim resulted in two small gas wells in Fentress County, which will be used to augment the supply for Jamestown. The producing horizons are shaly limestones of Ordovician (Trenton) age. Two wells in this area tested the upper part of the Knox dolomite group, one of which encountered some free oil in a sandy dolomite at 1670 to 1681 ft. A test high on a well-defined structure in Clay County found a considerable amount

Jan 1, 1942

By Kendall E. Born

Production of crude oil in Tennessee during 1941 was slightly more than 15,000 bbl., about the same as in the preceding year. Two thirds of the total was from the Mississippi limestone pools in Scott and Morgan Counties. About a dozen small scattered wells in Clay, Pickett, and Fentress Counties, pumped irregularly, produced approximately 5000 bbl. Natural gas was marketed from wells in Morgan and Fentress Counties for consumption in the Sunbright and Jamestown areas, respectively. The production by counties is shown in Table I. Drilling activities in the state fell to the lowest stage since 1933. Twenty-seven wells were spudded in during 1941, of which six were drilling or only temporarily suspended on Dec. 37, 1941. Of the 22 completions, four were gas wells of undetermined quantity, but are classed as commercial, and 17 were dry or near-dry holes. One well encountered oil, but it has not been tested. The total footage drilled during the year was 29,916 ft.; the average depth of wells was 1359 ft. The more important wildcats are listed in Table 2; the distribution of tests according to physiographic divisions is given in Table 3. East Tennessee.—One well was drilled to 3480 ft. in northwestern Anderson County, in the highly disturbed Appalachian area, a region long considered the most unfavorable in the state for the accumulation of oil and gas. Another test is now drilling below 2000 ft. in this general area. Cumberland Plateau.—There were two completions in the Cumberland Plateau area. One test, drilled in northwestern Scott County in an area of former Mississippi limestone production,' encountered a considerable amount of free oil at 850 ft., about the same horizon as in the old abandoned wells. No pumping tests have been made to date. A well at Oneida, Scott County, found gas at 1579 ft. in a sandy limestone of lower Mississippian age. The volume was reported doubled by a shot, although no open-flow measurement is available. Eastern Highland Rim.—Six completions on the eastern Highland Rim resulted in two small gas wells in Fentress County, which will be used to augment the supply for Jamestown. The producing horizons are shaly limestones of Ordovician (Trenton) age. Two wells in this area tested the upper part of the Knox dolomite group, one of which encountered some free oil in a sandy dolomite at 1670 to 1681 ft. A test high on a well-defined structure in Clay County found a considerable amount

Jan 1, 1942

By Stuart St. Clair

In view of the great interest shown in the oil possibilities of Kentucky, one is impressed with the paucity of reliable literature on the oil fields of the state. A few brief reports by the Federal and State Geological Surveys are about the only reliable data available. When the estimated production figures, for 1918, are published by the U. S. Geological Survey, they will show a revival of the oil industry in the Blue Grass State during the past half decade. There will also be an increase in the production for 1919 and 1920, at least. Although as an oil-producing state Kentucky is small, compared with some of the other oil states, the present production and the area of undrilled proved territory is large enough to classify it as one of the important oil states of the Union. This paper will be confined to the Irvine District and the immediately adjoining areas which have been prospected with varying success. The Corniferous limestone or Irvine sand is the oil-producing formation in the area discussed. In my divisional nomenclature, the Irvine District includes the Irvine field, which extends from the town of Irvine eastward toward Campton; the Big Sinking area, which joins and lies to the south of the eastern part of the Irvine field; the Beattyville area, which lies to the north and northeast of the town of that name and joins the Big Sinking area; and the Ross Creek pool, which lies to the southwest of the big production and across the Kentucky River. Except for the Ross Creek pool, the main producing area is bounded on the east by the L. & E. R. R. and on the west and south by the Irvine Branch of the L. & N. R. R. Winchester and Lexington form the gateways and Torrent on the east, Irvine on the west, and Beattyville on the south are the principle entrances to the main fields. Evelyn, on the L. & N. R. R., south of Irvine, is the point of entrance to the Ross Creek area. Geology The geology of the Irvine District is very simple. The rock formations with which the oil man should acquaint himself lie between the lower measures of the Pennsylvanian sandstones and shales and the Devonian or Corniferous limestone, or Irvine formation. Only a very brief description of these formations will be given, as they have been described fully by E. W. Shaw.'

Jan 1, 1921

L. C. Graton, Cambridge, Mass.—The subject of chalcocite occur; rence and its geological significance has, of course, a very important commercial bearing, as shown by the recent remark of a hard-headed mining .man: "This secondary enrichment business is one thing you geologists have put up which we can hang on to, and come out right." Most enrichments of copper ores depend upon the formation Of chalcocite from leaner sulphides. Recently it has been shown that not only does there exist this secondary or derived chalcocite, * but that in certain ores the mineral is present as an initial or original constituent, which therefore we may call primary. The desirability of distinguishing between these two kinds of chalcocite is evident and has recently been emphasized. That constitutes the first problem in this connection. I believe many who are working upon secondary enrichment of mineral deposits are giving much attention to that particular question. It is now possible to distinguish primary from secondary chalcocite in many cases. In such cases, what do we know of the' conditions under which this secondary or derived chalcocite was formed? , This is the second main question in connection with the subject. It is now plain, at least in many instances, that the formation of this derived chalcocite represents a phase of oxidation if we have in mind the primary ore as the thing acted upon. The next important question—and it is most important—is: does such oxidation go on above the zone where the rocks are saturated with water—that is, above the water level—or below, or indiscriminately above and below? Many of you have, or have had, opportunities to study at first hand, day after day, occurrences that' enable valuable conclusions to be drawn upon these and other important questions concerning the formation and significance of chalcocite. It is greatly to be hoped that your testimony will be made available and undoubtedly it will go far toward clearing up some of these doubtful points. John D. Irving, New Haven, Conn.—A short time before this meeting was called, H. V. Winchell, who was unable to be present, requested me to exhibit and describe these two samples of pyrite. (Exhibiting specimens.) They consist of fragments of pyrite inclosed in two small bottles. The first bottle shows fragments of pyrite which were immersed in water carrying copper sulphate but without SO2 for a period of two years. They remained comparatively clear and bright. No chalcocite has been deposited on them. The second bottle shows fragments of

Jan 1, 1915

By Linda P. Bono

Some mining engineers are pursuing their destinies in places far removed from what they might have envisioned back in the classroom. The path they follow to work each day may wind down Wall St., Park Avenue, LaSalle, or Market; their offices are in modern skyscrapers which offer all the amenities-air conditioning, thick carpets, attractive decor, and executive lunchrooms, to name just a few. The papers on their desks are a combination of financial figures and feasibility studies. But even in these surroundings there are indications of what these men do and where their professional interests lie-minerals are everywhere, from vast collections to one symbolic paperweight. . . there are sometimes specks of dirt under fingernails from a recent on-site inspection, belying the traditional banker's garb. . . and there are the wistful comments about finding it necessary to get out in the field.

Jan 9, 1978

By A. K. Knickerbocker

PRACTICALLY all underground work on the Minnesota iron ranges is done by miners working on a so-called contract wage system. This system, while it has certain advantages over the straight day's pay or company-account method of wage payment, has serious and vital defects. In view of the scarcity and demands of labor, it is important that employers of labor scrutinize their systems of wage payments carefully, not only to save losses and trouble, due to labor disturbances, but also to secure the greatest efficiency of their workmen and reduce their operating costs. It is admitted that an adequate, just, and equitable wage is the prime factor in bringing about these benefits. The wage of labor and its method of application and payment have been, and always will be, the main factors in the unrest and dissatisfaction of labor. Not only does labor want and need an adequate wage, assuming that work is adequately performed, but it wants and is entitled to a just and equitable wage. Labor must have respect for the fairness of the wage and for the fairness of the management in the application of the wage. It is conceded that the Minnesota iron miners are now, and have been, in the main paid adequately, but the inherent defects of the so-called contract system prevent any just or equitable application of this wage to the various units of the labor body. The defects of the contract system, with its obvious inequalities, favoritisms, and injustices, are cancers in the brain of labor. Every thinking miner realizes these defects and knows just what they are; the unthinking do not realize the details of the subject, but each month they are forcibly reminded of these defects through the pay envelope. As practiced on the iron ranges, however, the so-called." contract" system is not a contract and the name is a misnomer. No true contractual obligation exists.

Jan 2, 1920

By M. R. Tek, R. L. Nielsen

The scaling laws as formulated by Rapoport relate dynamically similar flow systems in porous media each involving two immiscible, incompressible fluids. A two-dimensional numerical technique for solving the differential equations describing systems of this type has been employed to assess the practical value of the scaling laws in light of the virtually unscalable nature of relative permeability and capillary pressure curves and boundary conditions. Two hypothetical systems — a gas reservoir subject to water drive and the laboratory scaled model of that reservoir — were investigated with emphasis placed on water coning near a production well. Comparison of the computed behavior of these par ticular systems shows that water coning in the reservoir would be more severe than one would expect from an experimental study of a laboratory model scaled within practical limits to the reservoir system. This paper also presents modifications of the scaling laws which are available for systems that can be described adequately in two-dimensional Cartesian coordinates. INTRODUCTION Present day digital computing equipment and methods of numerical analysis allow realistic and quantitative studies to be carried out for many two-phase flow systems in porous media. Before these tools became available the anticipated behavior of systems of this type could be inferred only from analytical solutions of simplified mathematical models or from experimental studies performed on laboratory models. To reproduce the behavior of a reservoir system on the laboratory scale, certain relationships must be satisfied between physical and geometric properties of the reservoir and laboratory systems. Where the reservoir fluids may be considered as two immiscible and incompressible phases, the necessary relationships have been formulated by Rapoportl and others.2-5 Rapoport's scaling laws follow from inspectional analysis of the differential equation describing phase saturation distribution in such systems. It will be recalled that these scaling laws presuppose three conditions: (1) the relative permeability curves must be identical for the model and prototype; (2) the capillary pressure curve (function of phase saturation) for the model must be linearly related to that of the prototype; and (3) boundary conditions imposed on the model must duplicate those existing at the boundaries of the prototype. These three requirements seldom if ever can be satisfied in scaling an actual reservoir to the laboratory system because: (1) The laboratory medium normally will be unconsolidated (glass beads or sand) while the reservoir usually is consolidated. Relative permeability and capillary pressure curves are usually quite different for consolidated and unconsolidated porous media. (2) The reservoir usually will be surrounded by a large aquifer which could be simulated in the laboratory only to a limited extent. (3) Wells present in the reservoir would scale to microscopic dimensions in the laboratory if geometric similarity is to be maintained. In view of these considerations, rigorous scaling of even a totally defined reservoir probably would never be possible. The purpose of this paper is to assess the practical value of the scaling laws in the light of the unscalable variables. This has been done by carrying out numerical solutions in two dimensions to the differential equations describing the flow of two immiscible, incompressible fluids in porous media for a field scale reservoir and a laboratory model of that reservoir. While both the reservoir and the laboratory model were purely fictional, each has been made as realistic and representative as possible. The field problem selected as the basis for the investigation was an inhomogeneous, layered gas reservoir initially at capillary gravitational equilibrium and subsequently produced in the presence of water drive. The laboratory model of this reservoir was designed to utilize oil and water in a glass bead pack. The numerical treatment employed was similar to that of Douglas, Peaceman and Rachford6 and it included both capillary and gravitational forces as

By Y. Kondo, A. M. Gaudin

A combined method for sizing in the sub-micron range was developed using centrifugation and gamma emission. Its essential features are: 1) Centrifugation of suspended mineral in water carried out at 4°C where water has its maximal density and zero temperature gradient of density 2) Gamma activition of the sample suspension induced by irradiating it in a nuclear reactor prior to centrifugation 3) Measurement of the activity of a beam of suspension as it is sedimenting in the centrifuge, using a scintillation counter provided with a discriminator. Albite, the sodium feldspar, was used as feed to the comminution step, and the induced gamma activity of Na24 was measured. Dissolved sodium ion caused a a non-settling activity in the measurement. Other "noise" is due to scattered gamma radiation from albite particles in the centrifuge outside of the line of sight. These two activities were obtained sep arately and subtracted from the total activity counted. The relative solid concentration in the suspension under the collimating slit is proportional to this net activity. The cumulative weight per cent of undersize particles was calculated and plotted against size on logarithmic scales. The relationship was found to be linear down to about 30 mµ. The specific surfaces calculated from particle size distribution agree with those measured by krypton gas adsorption. The measurement of particle size distribution of comminution products has been of interest in clarifying the mechanism of the process. The Gaudin-Schuhmann equation1,2 relates the cumulative percentage undersize, y, to relative particle size x/k. The particle size, x, and the size modulus, k, together with the distribution modulus, m, characterize the particle size distribution, m is the slope of a plot of log (y) against log (x/k). This equation has been verified for ground particles down to 1 micron in size.3'4 For particle sizes smaller than a few microns, the precision and facility of sedimentation and microscope techniques become questionable. Use of a centrifuge which shortens settling time from weeks to hours is attractive. Many centrifugal methods have been proposed; however, determination of the solid concentration of the suspension at a reference level as a function of time is difficult, and sampling the suspension is likely to introduce errors. Measurement of particle size distribution by X-ray absorption in gravitational5 and in centrifugal6 sedimentation have also been tried. In these methods, the absorption coefficient for the solid is independent of size, since the wave lengths of the X-rays and gamma-rays are orders of magnitude smaller than the particles. Radiometric techniques7 in size distribution measurement have been developed within the last several years. They offer advantages over usual gravimetric and optical methods. PRINCIPLE OF METHOD The combined method of centrifugation and gamma emission for sizing in submicron range described in the present paper has the following essential features. 1) Centrifugation is carried out at 4 ± 0.1°C. Convection currents in the water phase due to density changes caused by temperature variation may disturb completely the settling system. To avoid this difficulty, the unique property of water having zero temperature gradient of density at 4°C is used. 2) Prior to size measurement the sample suspension is irradiated in a nuclear reactor and gamma activity induced. The gamma activity of the particles sedi-mented radially is measured by a scintillation counter provided with a discriminator. By this method, interruption of centrifugation by withdrawing samples is avoided and the counting rate at any time represents the solid concentration in the suspension at the level of the collimating slit of the centrifuge at the particular time at which the measurement is made. 3) By proper selection of the feed material and of the comminution device, gamma activities of foreign

Jan 1, 1964

By P. T. Bail, J. E. Bobek

In reservoirs containing soft shales interbedded with oil-producing sands, it is possible to have water movement from the shales into the sands during reservoir depletion. This paper presents the results of scaled flow-model tests performed to investigate the efficiency of oil displacement by this vertical influx of water into oil-producing sands. In these model tests, the effects of rate of influx and rock wettability were considered. Oil recoveries by shale-wafer influx and by water flooding were cornpared after 0.4 hydrocarbon volume of water entered the producing sand. This comparison was made for water-wet and oil-wet systems. In water-wet sand, shale-water influx produces slightly less oil than conventional water flooding; in oil-wet sand, shale-water influx produces about one-half as much oil as conventional water flooding. In another type of comparison, it was found that shale-water influx followed by water flooding recovers less oil than water flooding alone. This is true for both water-wet and oil-wet sands. A comparison of tests run at different rates of shale-water influx shows that oil recovery is insensitive to rate in water-wet sand; in oil-wet sand, oil recovery decreases with decreasing rate of influx. INTRODUCTION Localized subsidence of the earth's surface has accompanied the depletion of some oil reservoirs, particularly in California,1, 2 along the Texas Gulf Coast,3 4 and in the Bolivar Coastal fields of Venezuela. Subsidence occurs when fluid withdrawals reduce the pressure in the reservoir. The reasons for subsidence accompanying a reduction in reservoir pressure are not known with certainty.10° However, there is considerable evidence that compaction of soft shale beds adjacent to producing oil sands can be a major cause of this subsi-dence.3, 6, 10-12 When the shales compact, a limited amount of water moves from the shales into the producing sands. A schematic illustration of this oil-producing mechanism is shown in Fig. 1. As the pressure in the sand declines due to oil production, a predominantly vertical pressure gradient develops at the sand-shale boundary. This causes water to move from the shale into the sand as indicated by the solid arrows. This paper reports the results of scaled flow-model tests to investigate the efficiency of oil displacement by the vertical influx of shale water into producing sands. The model tests were not performed with the aim of duplicating the recovery behavior of any specific reservoir. The primary purpose of the tests was to obtain a better understanding of oil displacement by shale-water influx. A knowledge of the oil- and water-production characteristics of even a simplified reservoir system should be of value to engineers estimating the performance of reservoirs where shale-water influx is occurring in conjunction with other production mechanisms. The following limitations and assumptions apply to the model work. 1. The sand of the prototype reservoir is homogeneous and horizontal. 2. The shale-water influx is uniformly distributed along the top and bottom of the sand member being studied. 3. No effects of edge-water drive or dissolved-gas drive that might accompany shale-water influx are considered. PROTOTYPE RESERVOIRS Scaled-model tests were performed to study oil displacement from three prototype reservoir sections. The reservoir sections modeled consist of single sand layers out of a sequence of -sand and -shale layers, as illustrated in Fig. 1. Each prototype represents a homogeneous, high-permeability, unconsolidated sand layer. In the field, the prototype is oriented in such a manner that one end is at the radius of drainage of a producing well and the other end is pointed toward the producing well (Fig. 2). The sand and fluid properties and the dimensions of the three prototypes are given in Table 1. The capillary pressure relationships for the three prototypes are presented in Figs. 3, 4 and 5. The oil-water per-

By Boris J. Kochanowsky

In a mobile crushing unit system trucks are replaced by a conveyor, which results in a continuous, almost fully automated operation with all its attendant advantages. Because of new designs for large mobile crushing units that have been placed on the market, the use of these plants has increased significantly during the last three years. Gains in productivity and reductions in costs are vital to every mine operator, and the shovel-crusher-conveyor system is a powerful tool with which to achieve this goal. New Designs Increase Throughput While Reducing Size The basic concept of the shovel-crusher-conveyor scheme of operations is simple and sound, with the result that domestic operators are showing a growing interest in its application. A number of operators have been using small mobile crushing plants for several years, but large operators, in spite of considerable interest, have not been able to use this system because no mobile crusher capable of crushing 1000-2000 tph of rock loaded by a large shovel (6-12 cu yd) has been available. A suitable crusher must accept rock of the size handled by these large shovels, be simple in design, easily maneuverable, remotely controllable, and have price and maintenance costs not much higher than those for stationary crusher installations.

Jan 9, 1968

By David E. Nicholas

INTRODUCTION In this paper, a numerical process for selecting a mining method, with the emphasis on underground mass mining techniques, such as caving, induced caving, and stoping, is proposed. In the past, selection of a mining method for a new property was based primarily on operating experience at similar type deposits and on methods already in use in the district of the deposit. Then, the chosen method was modified during the early years of mining as ground conditions and ore character were bet- ter understood. Today, however, the large capital investment required to open a new mine or change an existing mining system make it imperative that the mining methods examined during the feasibility studies and the method actually selected have a high probability of attaining the projected production rates. Although experience and engineering judgment still provide major input into the selection of a mining method, subtle differences in the characteristics of each deposit, which may affect the method chosen or the mine design, can usually be perceived only through analysis of measured characteristics. The parameters that must be examined when choosing a mining method include: 1) geometry and grade distribution of the deposit; 2) rock mass strength for the ore zone, the hanging wall, and the footwall; 3) mining costs and capitalization requirements; 4) mining rate; 5) type and availability of labor; 6) environmental concerns; and 7) other site-specific considerations. This paper encompasses a detailed look at the first two parameters since they, plus mining costs, have the greatest impact on the selection of a mining method. The proposed method selection process is for a project where drilling has defined sufficient geologic reserves, but little or no underground development has been done. Since each deposit has its own characteristic geanetry/grade distribution, and rock mechanics properties, mining method selection should be at least a two-stage process. In Stage 1, the deposit is described in terms of geometry, grade distribution, and rock mechanics properties. Using these parameters, the mining methods can be ranked to determine which are most applicable; they can then be considered in general terms of mining and capitalization cost, mining rate, type and availability of personnel, environmental concerns, and other site-specific considerations. In Stage 2, the most likely mining methods are costed out, based on a general mine plan. Mining and capitalization costs are used to determine a cut-off grade fran which a minable reserve can be calculated; economic comparisons can then be made to determine the optimum mining method and economic feasibility. During the mine planning phase of Stage 2, rock mechanics information would be used to provide realistic estimates of underground opening size, amount of support, orientation of openings, and caving characteristics, and open pit slope angles. If ground control or operational problems should be encountered with the methods being considered, modifications could be made. Although planning on paper extends start-up time, it is cheaper to err on paper than to find the error after mining has begun. METHOD SELECTION - STAGE 1 The main purpose of Stage 1 is to select those mining methods which should be considered in greater detail. The simplest way to do this is by defining those characteristics required for each mining method and then determining whether the characteristics of the deposit are suitable. However, no one mining method is so restrictive that it can be used for only one set of characteristics, as indicated by the classification system proposed by Boshkov and Wright (1973). In the mining method selection proposed, geometry, grade distribution, and rock mechanics characteristics are ranked according to their acceptability for ten general mining methods.

Jan 1, 1981