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By John H. G. Monypenny

The range of chromium content of stainless steel is, in most cases, included in the limits 11 to 14 per cent., or the middle part of the range, 9 to 16 per cent., specified by the discoverer. For some time after the steel was produced commercially, the carbon content was about 0.3 to 0.4 per cent. and occasionally higher; only rarely was material with 0.25 per cent. carbon or less produced. The reason for this is obvious from the nature of the alloys of chromium available for making such steels; as the lowest carbon content generally available was about 1 per cent., and this in conjunction with a chromium content of about 60 per cent., the production of a 12-per cent. chromium steel with less than 0.25 to 0.30 per cent. carbon was impossible. The advent, on a reasonable commercial scale, of carbonless ferrochromium has modified this condition, however, so that for the last three years stainless material containing 0.1 per cent. or less carbon and the normal amount of chromium has been on the market. As far as the author is aware, the material was first made on a commercial scale by the firm with which he is associated in June, 1920, when a 5- or 6-ton cast of material containing 0.07 per cent. carbon and 11.7 per cent. chromium was made and cast into 12-in. ingots. The necessity for using a totally different raw material, carbonless ferrochromium, instead of the ordinary low-carbon ferro (0.6 to 1.0 per cent. carbon) has led to the idea that stainless iron is a quite distinct product and quite different from stainless steel. While this may be true from a commercial aspect, it is wrong metallurgically. The name stainless iron is unfortunate as the material is a very mild stainless steel and forms the lowest carbon member of a series of steels of continuously varying content which are, in many respccts, the counterpart of the series of ordinary carbon steels ranging from "dead soft" to tool steels. In an article on stainless steel in the Journal of the Society of Chemical Industry, November, 1920, the author said "Just as in the far-off days 'steel' was regarded as a hard product of iron, and little or no attempt was made to grade it into harder or softer varieties, so at present stainless

Jan 1, 1924

By H. A. Jr. Koch, C. A. Hutchinson

Miscible phase displacement of oil from reservoirs has been emphasized in the past few years. The reason for this emphasis lies in the high oil recovery attainable by this process. Removal of capillary effects in the reservoir leads to recoveries approaching 100 per cent in the area contacted by the miscible phase. The miscible slug process is one means of obtaining a miscible displacement. Here a band or slug of I,PG is injected into the reservoir prior to gas injection. The idea is to maintain the band of LPG "wedged" between the gas and oil phases and thus achieve a miscible phase displacement. A second method lor achieving miscibility is through the injection of a gas which is not miscible with the reservoir fluid but which develops a zone of miscibility in [he reservoir through mass trans-ier with the reservoir oil.' This mass transfer results in either an enrichment of the lean injected gas by intermediates from the oil or an enrichment of the oil by intermediates from a rich injection gas or one that has been enriched on the surface by LPG addition. We are interested here in discussing the process in which miscibility is developed at the displacement front by the evaporation of interrnediatcs from the oil phase into the gas phase. This process "builds up" its own slug of miscible material at the displacement front and therefore does not require the injection of LPG to obtain miscibil-ily. Each process has its own area of applicability. Generally, the high pressure gas process is applicable only with reservoir fluids which con-!ain a high concentration of inter- mediates. If the high pressure gas process is technically feasible at pressures less than 4,500 psi, it is probably more desirable economically than the slug process. The slug process has broad applicability in the shallower reservoirs and with reservoir fluids which contain a relatively low concentration of LPG and natural gasoline constituents. This paper deals with some new concepts of the high pressure gas injection process where it is proposed that flue gas can be substituted for hydrocarbon gas without sacrificing our goal of miscibility. MECHANISM Introduction Considerable effort has been devoted to study of the mechanics ot the high pressure gas injection proc-one generalization result-ing from some of these studies was that the composition of the injected gas is relatively unimportant in establishing the miscibility pressure* for a given reservoir fluid. This generalization is correct for the composition range of gases typically encountered in the field. Two such gases are a gasoline plant tail gas containing 85 per cent methane and 15 per cent ethane, and a field separator gas containing 70 per cent methane and 30 per cent heavier components. The most important factor which sets the miscibility pressure in the operation is the reservoir fluid composition, particularly the concentration of LPG-natural gasoline constituents. The injected gas is the agent by which the LPG-natural gasoline constituents are concentrated at the displacing front to create a miscible displacement. Based on these results, it appeared feasible that some inexpensive gas, such as flue gas, might be substituted for hydrocarbon gas for use in the high pressure gas process. A re-examination of the phase relations of the high pressure gas injection process should clarify the principle behind using flue gas (essentially nitrogen) as an injection gas. Three Component Diagram The phase relations of the high pressure gas injection process have been illustrated by the use of the three component diagrams.'," In Fig. 1 we have arbitrarily represented the multi-component reservoir system by three components; methane, ethane through hexane, and heptanes plus. The solid curve ABC is the phase boundary curve. It represents the locus of compositions which have fixed saturation pressure at a fixed temperature; the lower branch AB shows bubble point compositions, the upper branch BC, the dew point compositions. Point B is the coniposition of the critical mixture at this temperature and pressure. The dashed lines (tie lines) connect vapor and liquid compositions which are in equilibrium. Let us consider Reservoir Fluid D which we wish to displace in 21 miscible manner by gas injection. Let us further restrict the discussion to the case where miscibility between an injection gas and the reservoir fluid at the displacement front is developed by gas enrichment in the reservoir. For this case, any gas whose composition lies between Points C and E on the right side of the three component diagram can be used to give a miscible displacement of Reservoir Fluid D. This is true because the more mobile injected gas moves faster than the displaced oil and is in continuous contact with virgin oil at the displacement front. This leads to a continuing enrichment 01' the gas at the displacement front by evaporation of the C, - C,

By Sidney A. Swensrud

The 24-in. crude-oil line. and- the 20-in. petroleum-products line, built as a war emergency by the United States Government and running from points in Texas to the New York-New Jersey-Philadelphia area, were constructed only because of the inability during the war to continue nor-inal ocean tanker movements from the Gulf Coast to the East Coast. The postwar disposition of these lines may be considered as one of the important problems of the postwar readjustments in the oil industry, if not the most important one. In the first place there appear to be many complications in keeping the lines in crude-oil or petroleum-products service. This conclusion was reached also in a study by T. E. Swigart, President of Shell Pipeline Corporation.' Since the lines are too largc for any one company to utilize, and since it appears likely that a surplus rather than a deficiency of tankers will exist after the war, most companies probably will feel that they can achieve lower costs and more satisfactoiy results from the resumption of tanker movements to the East Coast rather than by endeavoring to take over or utilize the capacity in the large pipe lines under some tariff-rate structure. As for using the lines for making deliveries to the middle west or central eastern areas, it would appear that when the war is over and normal transportation arrangements can be resumed, there will be no need of any extra capacity for such deliveries. Therefore, the War Emergency lines could be utilized for this purpose only if privately owned pipe lines and other transportation facilities were to be displaced. Against this rather unprepossessing prospect for use in petroleum or product service is the fact that at or near the source of the lines lie the greatest developed gas reserves in the world, for much of which there is at present no satisfactory market outlet; and at the other end of the lines lies one of the greatest concentrations of population in the world, which is not now served by natural gas. These who have been fortunate enough to use natural gas can have little doubt of its desirability as a domestic fuel. An analysis of the market potentialities and comparison with other areas where natural gas is being distributed, and where it has displaced manufactured gas, makes it seem clear beyond question that the full capacity of both of the large-diameter lines could be fully utilized in this service, and this without creating any undue drain upon the gas reserves of the nation. On the basis of an estimated capacity of roo to 120 billion cubic feet per year, the gas that might be marketed through these lines would amount to only 3 to 4 per cent of the total con-

Jan 1, 1944

By Sidney A. Swensrud

The 24-in. crude-oil line. and- the 20-in. petroleum-products line, built as a war emergency by the United States Government and running from points in Texas to the New York-New Jersey-Philadelphia area, were constructed only because of the inability during the war to continue nor-inal ocean tanker movements from the Gulf Coast to the East Coast. The postwar disposition of these lines may be considered as one of the important problems of the postwar readjustments in the oil industry, if not the most important one. In the first place there appear to be many complications in keeping the lines in crude-oil or petroleum-products service. This conclusion was reached also in a study by T. E. Swigart, President of Shell Pipeline Corporation.' Since the lines are too largc for any one company to utilize, and since it appears likely that a surplus rather than a deficiency of tankers will exist after the war, most companies probably will feel that they can achieve lower costs and more satisfactoiy results from the resumption of tanker movements to the East Coast rather than by endeavoring to take over or utilize the capacity in the large pipe lines under some tariff-rate structure. As for using the lines for making deliveries to the middle west or central eastern areas, it would appear that when the war is over and normal transportation arrangements can be resumed, there will be no need of any extra capacity for such deliveries. Therefore, the War Emergency lines could be utilized for this purpose only if privately owned pipe lines and other transportation facilities were to be displaced. Against this rather unprepossessing prospect for use in petroleum or product service is the fact that at or near the source of the lines lie the greatest developed gas reserves in the world, for much of which there is at present no satisfactory market outlet; and at the other end of the lines lies one of the greatest concentrations of population in the world, which is not now served by natural gas. These who have been fortunate enough to use natural gas can have little doubt of its desirability as a domestic fuel. An analysis of the market potentialities and comparison with other areas where natural gas is being distributed, and where it has displaced manufactured gas, makes it seem clear beyond question that the full capacity of both of the large-diameter lines could be fully utilized in this service, and this without creating any undue drain upon the gas reserves of the nation. On the basis of an estimated capacity of roo to 120 billion cubic feet per year, the gas that might be marketed through these lines would amount to only 3 to 4 per cent of the total con-

Jan 1, 1944

By R. H. Kolb

A long term project at Shell Development Co.'s Exploration and Production Research Laboratory has been the improvement of the accuracy and the ease of BHP measurements. As a result of these efforts, two complete and separate systems have now been built for the automatic logging of BHP variations. The first of these is a small-diameter instrument suitable for running through production tubing on a single-conductor well cable. During the development of this instrument, as much emphasis was placed on providing a high degree of usable sensitivity and repeatable accuracy as on obtaining the advantages of surface recording. The second system combines the benefits of automatic, unattended recording with the convenience of a permanently installed Maihak BHP transmitter.' THE CABLE INSTRUMENT For many years the standard instrument for BHP determination has been the wireline-operated Amerada recording pressure gauge or one of several other similar devices. This gauge records on a small clock-driven chart carried within the instrument, and although relatively precise readings from the chart are possible, they are difficult to ob-tain. a Both the maximum recording time and the resolution of the time measurements are limited by chart size, and when a slow clock is required for long tests, the precision of the time measurement is often inadequate. Since it is impossible to determine the data being recorded until the gauge has been returned to the surface, wasted time often results when a test is protracted beyond the necessary time or when it is terminated too soon and must be re-run. Clock stoppage or other malfunctions which would be immediately apparent with surface recording remains undetected with down-hole recording; the test is continued for its full term with a consequent loss in production time. As new uses for subsurface pressure data evolved, the shortcomings of the wireline instrument became increasingly apparent, and the concurrent development of a surface-recording pressure gauge and the associated high-pressure well cable service unit' was undertaken. Description of the Instrument Because of its ready availability and advanced degree of development, the Amerada bourdon-tube element was chosen as the basic pressure-sensing device. This element converts a given pressure into a proportional angular displacement of its output shaft, and a suitable telemetering system was designed to measure accurately the extent of this displacement and to transmit the measurement to the surface and record it. The telemetering system furnishes a digital record printed on paper tape by an adding machine-type printer. The present arrangement provides a resolution of one part in 42,000 over the angular equivalent of full-scale deflection, giving a usable sensitivity of better than 0.0025 per cent of full scale. An additional refinement simultaneously records on the tape the time or the depth of the measurement, also in digital form. When the instrument is placed in operation, an adjustable programer can be set to initiate a read-out cycle automatically at selected time intervals. When subsurface pressures are changing rapidly, readings may be recorded as frequently as once every 10 seconds; when pressures are more nearly stabilized, the period between readings may be extended to as much as 30 minutes. Because the instrument is surface-powered as well as surface-recording, the maximum period of continuous logging is (for all prac. tical purposes) unlimited. The subsurface instrument is a tubular tool, 1 1/4-in. in diameter and 6.5 ft in length, operating on 12,000 ft of conventional 3/16-in. IHO logging cable. The transmitting section, mounted above the bourdon-tube element in place of the regular recording mechanism, contains no fragile vacuum tubes or temperature-sensitive transistors. This unit has been laboratory-tested to 1 0,000 psi and 300°F and has performed dependably during a number of field operations. The down-hole transmitting arrangement can be fitted to any standard Amerada pressure element, regardless of range and with no modification of the element itself. Calibration To obtain a repeatability commensurate with the sensitivity and resolution of the instrument, it was necessary to develop a special calibrating technique. The manufacturers of the Amerada recording pressure gauge claim an accuracy of only 0.25 per cent of full scale, which is a realistic figure for normal calibrating and operating procedures. An exhaustive investigation was made of the errors inherent in the bourdon-tube element, itself, independent

By Robert Mehl

THE precipitation of the nitride Fe4N from the solid solution of nitrogen in a Fe and of the phosphide Fe3P from the solid solution of phosphorus in a Fe both lead to the formation of structures that may be easily identified as Widmanstätten figures, within the meaning of the term as used in this series of papers. A complete solution has been obtained for the figure formed by Fe4N. The structure of Fe,P, however, is not fully known and a complete solution of this figure thus cannot be obtained; nevertheless, a study of this figure has furnished some new information. PRECIPITATION OF FE4N FROM ALPHA SOLID SOLUTION OF N IN ALPHA FE Constitution of System Iron-nitrogen A knowledge of the constitution of the whole of the Fe-N system is unnecessary for this work, though the recent studies by Eisenhut and Kaupp1 and by Lehrer2 have clarified most of the moot points; it is sufficient for our purpose to state that a Fe of high purity dissolves 0.42 per cent of nitrogen in solid solution at the eutectoid temperature, 591° C., and that this solubility decreases at first rapidly and then more slowly until at room temperature the solid solubility amounts to approximately 0.1 per cent nitrogen.3

Jan 1, 1934

By P. W. Ramsey, D. P. Kedzie

INCREASING demand for improved strength-weight ratios made on aircraft structures has resulted in a gradual increase in the tensile strength requirements for steels used in such applications. As the cyclic loads often are more critical than static loads, and the fatigue properties are generally the design criteria, the question arises as to whether an improvement in fatigue properties accompanies the increased tensile strength. The present investigation was undertaken to determine the relationship between fatigue and tensile properties for an aircraft quality steel in the 155 to 280 ksi (1000 psi) tensile strength range, using the Prot method of fatigue testing. Procedure and Results After preliminary work to establish proper heat treating procedures for this heat of aircraft quality electric furnace steel (a Ni-Cr-Mo-V steel," AMS- Prot Fatigue Testing Method—The determination of the endurance limit by the conventional Wohler method can be time-consuming and easily require 20 specimens when statistical variance is to be established. This is also true when endurance limit loads are determined on actual parts or subassem-blies, and the desirability of a reliable accelerated method has been evident for some time. The primary advantage of the Prot method of fatigue testing is in reducing the number of specimens and the time required for each test. Unlike the Wohler method, every Prot specimen tested con- tributes to the determination of the endurance limit, and the authors have been able to duplicate Wohler results obtained with 20 specimens with only half the specimens and a fourth of the total cycles. This new technique for defining the endurance limit was proposed in 1948' by Marcel Prot and consists of progressively increasing cyclic stress until fatigue failure occurs. By varying the load rate, a, a useful relationship is found to exist with failure stress, so that for steel the failure stress appears to

Jan 1, 1958

By Pieter W. Greeff, Graeme W. Mitchell

INTRODUCTION This paper describes the underground environmental planning parameters developed for Pancontinental Mining Limited's Jabiluka uranium deposit. The deposit is located 230 km east of Darwin in the Alligator Rivers region of the Northern Territory, Australia. The deposit is situated within land subject to an Aboriginal land claim, adjacent to a National Park and within a proposed extension to that National Park, as well as being close to a long- established Aboriginal reserve. In addition, being the first large underground uranium mine planned in Australia, the environmental considerations, both on surface and underground are considerable. Pancontinental is committed to the highest practicable standard of environmental management in the operation of the mine. In addition, Government regulations and requirements are particularly stringent by world standards. The underground environmental problems are discussed later in the paper with emphasis placed upon radiation aspects, both gamma and radon daughters, and dust. Consideration has also been given to heat and humidity due to the location of the deposit in a sub-tropical region 12° south of the equator. The paper explains how these environmental factors influence the design and selection of stoping methods. GEOLOGY AND ORE RESERVES The Jabiluka Two orebody is completely overlain by flat-bedded Kombolgie Sandstone with a thin layer of surficial colluvial sands. The orebody occurs in an east-west striking folded succession of Lower Proterozoic metasedimentary rocks of the Cahill Formation. Uraninite and pitchblende constitute essentially all the uranium mineralisation and are contained in the four lithological series, as shown in Fig. 1. - ,Upper Graphite Series - Main Mine Series - Lower Mine Series 1 - Lower Mine Series 2 The succession at Jabiluka has been folded and forms an east-south-east striking, asymmetric syncline-anticline which dips south and plunges to the east. A major fault bisects Jabiluka Tw8 having a north-south trend and dipping about 80 to the west. A near vertical tourmaline granitic pegmatite dyke up to 30 m in thickness has intruded the Jabiluka Two orebody at the western end. Current drilled ore reserves for Jabiluka Two are 52.0 million tonnes at 0.39% U308. Included in these reserves are 1.1 million tonnes of gold ore at 10.7 g/tonne. A large proportion of the orebody can be mined in thick sections (over 80% of tonnage) either as single sections or by bulking a number of thin sections which are close together.

Jan 1, 1981

By J. E. Pollock, W. R. Hicks, E. Camp

IN the oil-refining industry, steel comprises by far the greatest proportion of the materials used in construction work, but with an enormous number of alloy steels and nonferrous alloys available, and a greater knowledge of their properties and corrosion resistance, a substitution first in the "hot spots" and then in locations of moderately severe corrosive conditions will be made as the greater expense can be justified. In new construction work, advantage is taken of the experience already gained and appropriate materials used, whether for high temperatures and pressures demanding additional strength or for corrosive conditions. The locations, however, where equipment in operation constantly requires replacement will soon become evident, as will the necessity for replacement in more resistant materials, if considerable down-time is to be avoided. In what direction and how far to go in the matter of alloys then becomes a question of the highest importance. Obviously, any replacement with more costly material must be justified economically by the promise of longer life, thereby saving both material and installation costs besides the reduction of loss of production. Where the equipment is overcapacity and a regular schedule of cleaning periods is in force, the last item frequently must be ruled out and justification made on the basis of the first two only. Installation of material that will outlast the remainder of the equipment and have no recovery value must also be avoided; this is particularly important in temporary construction or in old equipment that will soon become obsolete. TEST METHODS Either one Of two methods or a combination of both, in the absence of reliable data in similar services, may be adopted to determine to what extent replacement with other, and perhaps more expensive, materials is justified. A unit may be constructed incorporating different metals or alloys so that comparative service may be obtained under the same service conditions; this has been applied in many instances, such as condenser and tank construction, but the opportunities for inspection may be few and

Jan 1, 1935

By Pol Duwez, H. E. Martens

The high temperatures encountered in the operation of jet engines have imposed most drastic requirements upon the materials used in their construction. There are two different approaches to the materials problem connected with the design of parts in contact with high temperature gases. The first approach is to use a material which will perform satisfactorily at a temperature comparable to that of the gas. The second approach is to use a cooling system so that the material is maintained at a temperature appreciably lower than that of the gas. Besides the conventional method of cooling by means of a liquid in contact with the material exposed to a high rate of heat transfer, a less orthodox method consists of making the part to bc cooled of a porous material', so that the cooling fluid can be forced through the pores, In this scheme, the temperature of the coolant moving in a direction opposite to that of the heat flow increases gradually while passing through the porous material, and the coolant forms a protective layer on the surface exposed to heat, This method, referred to as ((sweat cooling," was pro- posed at the Jet Propulsion Laboratory in September 1944, and the experimental work on the preparation of porous metals was started early in 1945. The sweat cooling method opens new lines of research in powder metallurgy by extending the field of application of porous metals. The porous metals available at the present time are used mostly as bearings or filters, and a rather limited number of alloys are made for these applications. In addition, the fabrication of bearings or filters does not require a very close control of the permeability, while in the case of sweat cooling such a control is of primary importance. In designing a sweat cooled part it is imperative to assure a given rate of flow of coolant under certain conditions of Pressure drop. Generally, the Proper pressure drop and the rate of flow of coolant are deduced from heat transfer and design considerations, and consequelltl~ the Permeability of the Porous metal to be used is also determined. It is therefore necessary for the designer to have available a continuous series of porous metals covering a range of permeability as wide as possible. Contrary to the requirements established in the fabrication of filters, the actual pore size of a porous metal intended for sweat cooling is of little consequence, except for its effect on permeability. The tensile strength is likely to be of great importance for some applications. Since the tensile strength of a porous alloy decreases with increasing porosity, an important problem is to develop porous alloys having the maximum permeability with minimum porosity.

Jan 1, 1949

By Arthur C. Green

A group of 13 cities situated in Los Angeles and Orange counties in Southern California is engaged in constructing an aqueduct to carry water from the Colorado River at a point near Parker, Arizona, to a distribution point near Riverside, California. The aqueduct will have a total length of approximately 241 miles, and is designed to deliver 1605 cu. ft. of water per second, or a little more than one billion gallons per day. The aqueduct crosses a barren, desert waste and the project includes approximately 91 miles of 16-ft. tunnel. The large amount of tunnel driving that has been done in this country in the past few years has resulted in some remarkable developments in equipment and methods. The building of the Colorado River Aqueduct,, with its 91 miles of tunnels, has called on the best engineering knowledge in the country. New and better equipment has been designed for all phases of the work, and this equipment has been coordinated and adapted to the various conditions with a high degree of efficiency. The result has been that records for tunnel driving have been set under adverse natural conditions that exceed the estimates for progress under good conditions. All of the tunnels in the main aqueduct, except the Valverde and Bernasconi at the western end, have a finished diameter, inside the concrete lining, of 16 ft. Fig. 4 shows a section of the tunnel with the concrete lining in place. Fig. 5 illustrates the finished tunnel in three typical sections. The standard tunnel grade is 3.432 ft. per mile in the 16-ft. tunnels, but the Valverde and Bernasconi tunnels have a steeper grade and a finished diameter of 15 ft. 3 in. The rough bore of the large main aqueduct tunnels averages 12.95 solid cubic yards of material per foot of advance in timbered sections and 10.76 solid cubic yards per foot in unsupported sections. Tunnel Driving While the Conway mucker has been used on tunnel work for years, a larger and more powerful Conway was designed to meet the require-

Jan 1, 1937

By H. M. Rutherford

THE reflection method in seismic prospecting has aroused much interest in the past few years. The purpose of the present paper is .to present the method of reflections in the mapping of geologic structure and also to give some indication of its limitations. The reflection method is well adapted to the mapping of geologic structure in the Mid-Continent fields, and has been found most useful there. The refraction method is ideally suited to the finding of structures, such as domes, where the amount of relief is very large. This explains the brilliant success of the refraction method in the Gulf Coastal region of Texas and Louisiana. The additional fact that salt has a much higher velocity than the sur-rounding sediments made their discovery much easier. By the use of the reflection method, differences of relief of 25 to 50 ft. to the mile may be detected at a depth of 5000 ft., and the depth points accurately plotted on a map. This is hardly possible by the use of the refraction method. The reflection method has been in almost continuous use in the Mid-Continent area since 1926, but very little, if anything, has been published until recently(7) ? regarding either the method or the results. The dis-covery of several oil fields is now attributed to the use of the reflec-tion method. Reflection methods have been used by the Germans to find the thick-ness of the ice of several glaciers. (2,8) The depths there considered were of the order of only a few hundred feet. For the method to be of any practical value in this country, it must be able to work to depths of several thousand feet. As was indicated above, this is now possible, though there are many problems connected with the reflection method yet to be solved. The refraction method requires that the shooting be done over long ranges. It was necessary, for example, to take distances out to several miles in order to penetrate some five thousand feet. Naturally this uses a good deal of dynamite. In the reflection method the distances are much shorter and the amounts of dynamite are much smaller, within limits which will be noted below. The chief distinction between refrac-tion and reflection methods is to be found in the analysis of the seismo-gram. Refraction shooting makes use of only the first arrival of energy

Jan 1, 1932

The present paper records a chapter in the history of the development of an electrolytic manganese industry in the United States.l A relatively large pilot plant at Boulder City, Nev., for the production of electrolytic manganese was conceived as part of the national defense program to make this country independent of foreign importation of manganese ore. The first authorization, in November 1940, however, was for a plant of only several hundred pounds capacity. Improvements in process and subsequent additions to some sections authorized by subsequent appropriations have enabled the plant to produce as much as 2000 lb. of manganese a day for substantial periods of time. Since in pilot-plant operation frequent changes are made in the flowsheet, the electrolytic manganese plant was constructed so that equipment could be rearranged with a minimum of expense and time. Several different kinds of the various ¦ types of equipment were installed for many of the operations, so that the one most suitable for the process might be chosen. Pilot-plant operations were begun in November 1941 and have been continuous except for brief shutdowns for installation of new equipment. More than one-half million pounds of manganese have been produced. The improvements in process, selection of equipment, and operational procedure developed are recorded here. Development of the Process The work of early investigators on the electrolysis of manganese solutions has been reviewed by Shelton. Until the method of continuous production of manganese by electrolysis was perfected by SheltonZm4 and coworkers, no practical procedure had been devised. The method as originally developed by the Bureau of Mines will be described here only briefly. The manganese dioxide ore was reduced in a rotating kiln-type furnace at 650°C. in an atmosphere of "city" gas. The calcine was leached with spent electrolyte and enough sulphuric acid to produce a neutral leach solutioil containing 2 5 grams manganese per liter as manganese sulphate and zoo grams per liter of ammonium sulphate. Arsenic was removed from the solution by the addition of 0.0j gram iron per liter as ferrous sulphate followed by oxidation with manganese dioxide, and aeration, which precipitated the iron as ferric hydroxide. The solution, free from iron

Jan 1, 1944

By A. T. Beckwith

The Lehigh Navigation Coal Company Inc. operates steep-pitch, relatively deep mines in the Panther Creek Valley, at the eastern end of the southern anthracite coal field. Commercially minable coal beds are the Mammoth,† Primrose, Orchard, and Buck Mountain;‡ their respective thicknesses average 50, 15, 10 and 12 ft. Sand slates immediately overlie and underlie these beds, though in some locations sandstone or conglomerate beds occur. Underground operations extend to a depth of 1200 ft. below the surface, and comprise a bulk of virgin work on the lower levels, and a small amount of remining on the upper levels. With increase in depth, ventilation has become a more important factor. Development In early days slopes or drifts were driven in the outcropping coal on the hillsides. Subsequent development was by water-level tunnels, with portals above high water in Panther Creek. These tunnels have been maintained because they intercept and drain much water that enters the mined-out portion of the bed and otherwise would follow down to the deep workings+ Below these tunnels, the coal was customarily developed by slopes. Muleways, which are zigzag chutes easy to travel, were also driven to connect lower openings with the water levels. When it became necessary to go still deeper, the slopes were abandoned, and vertical multicompartment shafts were sunk from the surface. Levels have been at vertical intervals of from 175 to 250 ft. Recent practice has been toward the latter spacing, splitting the total lift, however, by starting to mine from chutes extending halfway up to the level above. Chutes customarily are spaced at 50, 60 or 70-ft. centers along the gangways. At some mines, additional shafts have been sunk from the surface to the level containing the main pumping station, and these carry the discharge lines from the pumps. As the mines are ventilated by the exhausting system, both the hoisting and so-called water shafts serve as intakes. The main fan is always on the surface, and is connected with the return airways from the various levels by an air hole or a vertical shaft. For economy, when the present deepest levels were developed, and return-air shafts or air holes were not extended to the new level, but connections were made from the new level to that above by two or more holes. It is doubtful that this method will be continued, as complications in the system, increased resistance to flow, and other difficulties undoubtedly will counterbalance any economies this provision may afford. During the early years of mining, when operations were at no great depth, all development headings were driven in the coal bed. As mining progressed downward, increased ground pressures slowed develop

Jan 1, 1942

By A. T. Beckwith

The Lehigh Navigation Coal Company Inc. operates steep-pitch, relatively deep mines in the Panther Creek Valley, at the eastern end of the southern anthracite coal field. Commercially minable coal beds are the Mammoth,† Primrose, Orchard, and Buck Mountain;‡ their respective thicknesses average 50, 15, 10 and 12 ft. Sand slates immediately overlie and underlie these beds, though in some locations sandstone or conglomerate beds occur. Underground operations extend to a depth of 1200 ft. below the surface, and comprise a bulk of virgin work on the lower levels, and a small amount of remining on the upper levels. With increase in depth, ventilation has become a more important factor. Development In early days slopes or drifts were driven in the outcropping coal on the hillsides. Subsequent development was by water-level tunnels, with portals above high water in Panther Creek. These tunnels have been maintained because they intercept and drain much water that enters the mined-out portion of the bed and otherwise would follow down to the deep workings+ Below these tunnels, the coal was customarily developed by slopes. Muleways, which are zigzag chutes easy to travel, were also driven to connect lower openings with the water levels. When it became necessary to go still deeper, the slopes were abandoned, and vertical multicompartment shafts were sunk from the surface. Levels have been at vertical intervals of from 175 to 250 ft. Recent practice has been toward the latter spacing, splitting the total lift, however, by starting to mine from chutes extending halfway up to the level above. Chutes customarily are spaced at 50, 60 or 70-ft. centers along the gangways. At some mines, additional shafts have been sunk from the surface to the level containing the main pumping station, and these carry the discharge lines from the pumps. As the mines are ventilated by the exhausting system, both the hoisting and so-called water shafts serve as intakes. The main fan is always on the surface, and is connected with the return airways from the various levels by an air hole or a vertical shaft. For economy, when the present deepest levels were developed, and return-air shafts or air holes were not extended to the new level, but connections were made from the new level to that above by two or more holes. It is doubtful that this method will be continued, as complications in the system, increased resistance to flow, and other difficulties undoubtedly will counterbalance any economies this provision may afford. During the early years of mining, when operations were at no great depth, all development headings were driven in the coal bed. As mining progressed downward, increased ground pressures slowed develop

Jan 1, 1942

By Thomas L. Kesler

The Cartersville mining district, 35 miles northwest of Atlanta, Ga, has been of varying but continuous importance in the southern mineral industry during the past century. Noted chiefly for its production of brown iron ore, manganese oxide ores, barite, sienna, and magnesian limestone, the district and its environs have produced brick and tile clays, slate, gold, bauxite, and graphitic schist. Minor deposits of serpentine, sericite schist, copper ore, and red iron oxide have been prospected. The obvious deposits of brown iron ore, together with some associated specular hematite, were mined out years ago, although a little ore was left in the workings. Moderately steady production of sienna reached a peak about 1930, then declined rapidly. Manganese mining passed through a relatively active period from the World War to 1931, but has subsided to a small but rather constant output for the Birmingham market. However, the White Manganese Corporation has prepared for possible increased production by constructing a new washer capable of handling about 300 tons of ore per day. Principal activity in the district proper has centered for some years in the production of barite and magnesian limestone. General Geology Geologic relations of the ore deposits of this district are more or less similar to those of many Appalachian districts. The lowermost Cambrian formation, heretofore called Weisnerl in this region, supposedly partly or. wholly equivalent to the Erwin and Hesse quartzites as recognized to the northeast, is overlain conformably by the Shady† formation, also of Lower. Cambrian age. In the Cartersville district, the sedimentary rocks of these formations were folded with increasing intensity eastward, and were recrystallized.

Jan 1, 1941

By Thomas L. Kesler

The Cartersville mining district, 35 miles northwest of Atlanta, Ga, has been of varying but continuous importance in the southern mineral industry during the past century. Noted chiefly for its production of brown iron ore, manganese oxide ores, barite, sienna, and magnesian limestone, the district and its environs have produced brick and tile clays, slate, gold, bauxite, and graphitic schist. Minor deposits of serpentine, sericite schist, copper ore, and red iron oxide have been prospected. The obvious deposits of brown iron ore, together with some associated specular hematite, were mined out years ago, although a little ore was left in the workings. Moderately steady production of sienna reached a peak about 1930, then declined rapidly. Manganese mining passed through a relatively active period from the World War to 1931, but has subsided to a small but rather constant output for the Birmingham market. However, the White Manganese Corporation has prepared for possible increased production by constructing a new washer capable of handling about 300 tons of ore per day. Principal activity in the district proper has centered for some years in the production of barite and magnesian limestone. General Geology Geologic relations of the ore deposits of this district are more or less similar to those of many Appalachian districts. The lowermost Cambrian formation, heretofore called Weisnerl in this region, supposedly partly or. wholly equivalent to the Erwin and Hesse quartzites as recognized to the northeast, is overlain conformably by the Shady† formation, also of Lower. Cambrian age. In the Cartersville district, the sedimentary rocks of these formations were folded with increasing intensity eastward, and were recrystallized.

Jan 1, 1941

By C. E. Tsoutrelis

A new method for determining rock drillability in diamond drilling is discussed; the method takes into consideration both penetration rate and bit wear. The method is based on drilling a rock specimen under controlled laboratory conditions using a model bit. The technique used for determining the experimental variables is extremely simple, quick, and reliable. Drillability is then determined by the mathematics of drilling. In considering the different factors that affect diamond drilling performance, the nature of the rock to be drilled is of outmost importance since it affects significantly the drilling costs and such other variables as bit type and design, drilling thrust, and bit rotary speed. Many attempts have been made to study this effect by correlating actual drilling performances either to certain physical properties of the rock being drilled1-? or to test drilling data obtained under laboratory conditions.7-13 These attempts were aimed at providing a reliable method of predicting by simple means the expected rock behavior in actual drilling, thus giving the engineer a tool to use in estimating drilling performances and costs in different types of rock. The purpose of this paper is to describe such a method by which rock drillability (a term used in the technical literature to describe rock behavior in drilling) could be determined in diamond drilling. It is believed that the proposed simple and reliable method will cover the need of the mining industry for a workable method of measuring the drillability of rocks. It should be emphasized, however, that since drill-ability depends on the physical properties of rock and each drilling process (diamond, percussive, rotary) is affected by different or partly different rock properties,14-l6 the proposed method of determining rock drillability cannot be extended to the other drilling processes. The results presented in this paper form part of an extensive three-year research program carried out by the author in the laboratories of the Greek Institute of Geology and Subsurface Research. During this period the effects of the physical properties of rocks and of such operational variables as drilling thrust and bit rotary speed in diamond drilling were investigated in detail. DRILLABILITY CONCEPT The literature is not devoid of drillability studies. While there are a number of investigators1,3,5-7,9-0,12-13,17 who have attempted to establish by direct methods (i.e., drilling tests under laboratory conditions) or indirect (i.e., through a physical property of rock) an index from which the drilling performance in a given rock may be estimated, very few6-7,9,12, of the proposed methods seem to be of much practical value to the diamond drilling engineer and none to date has been universally accepted. Commenting on the proposed methods for assessing rock drillability, Fish14 remarks that "for a measure of drillability to be accepted it is essential that penetration rate at a given thrust and bit life are elucidated as otherwise the method is of little value." This statement should be examined in more detail by making use of the penetration rate-drilling time diagram obtained in drilling a rock under constant operational conditions. Furthermore, the merits of using this diagram to describe rock drillability will be pointed out. At the same time reference will be made to this diagram when discussing some previously proposed methods. Fig. 1 illustrates such a diagram for three rocks,A, B, and C, which have been diamond drilled under identical conditions. It is assumed here that rocks A and B have the same initial penetration rate, i.e., VOA = Vog, but since rock B is more abrasive than A, rapid bit wear occurs and as a result the fall of its penetration rate with respect to time is more vigorous than in rock A. This is shown graphically by a steeper V = f(t) (0 curve in this rock than in rock A. Rock C has a lower initial penetration rate, due to higher strength properties16 but since it is not very abrasive, only a slight fall of its penetration rate occurs during drilling (in this category are some limestone and marbles with compressive strength above 1000 kg per sq cm). It follows from the foregoing considerations that the characteristic for each rock curve (I) is a function of (i), the penetration rate of the rock Vo recorded at the instant of commencing drilling, which determines the starting point of the curve (1) on the y-axis and (ii), the abrasive rock properties which determine the rate of fall of Vo with respect to time. Thus, curve (I) provides an actual picture of the rock behavior in drilling for given operational conditions, and it can be used with complete satisfaction to assess rock drillability. It can be seen clearly from Fig. I that proposed methods for assessing rock drillability by measuring the

Jan 1, 1970

By John P. Cosgro

THE increasing use of internal furnace-boilers for mining power-plants (doubtless due to the facility with which they may be installed by reason of their portability; the fact that they require no masonry setting, cast-iron fronts, buck-stays, etc., and practically no foundation; and the successful maintenance of their claim to equal and even superior economy, as compared with boilers of other types) warrants this description of a method of remedying an injury which may occur, to such a furnace, even though it satisfies the requirements of the formula adopted by the U. S. Board of Supervising Inspectors of Steam Vessels.2 I refer to the sagging and deformation which may result from overloading the boilers for a considerable period-say, several days. This is sometimes unavoidable under the exacting conditions of continuous day-and-night service, and (in spite of all rules and precautions, the occasional careless or unskillful work of attendants. Such a trouble is by no means unknown on shipboard, where this type of boiler is so largely employed. In the case here described, two Morrison suspension-furnaces, of half-inch steel, 14 ft. long and 45 in. in mean diameter, with ? dry-back ? boilers, were necessarily operated somewhat beyond their rated -normal capacity for several months, while a third similar unit was -in process of installation, and during this period, though the boilers were kept perfectly clean, heat seems 'to have been generated slightly faster than it was absorbed by, the water in the boilers. The corrugations of this.

Mar 1, 1905

By H. C. George

Since 1911, when J. L. Dunn first used compressed air for repressuring depleted oil sands in southeast Ohio, the rejuvenation of many depleted oil fields has been directly due to repressuring by means of air or gas. Developments in repressuring in recent years have resulted in its successful use in the early life of some deep, high-pressure oil fields, conserving the natural gas dissolved in and associated with the oil by returning it to the producing oil sand after it has been compressed above the existing rock pressure of the reservoir. One of the most successful operations of this type is that of the Humble Oil & Refining Co., on the DeWalt salt dome at Sugarland, Texas. I quote from a personal communication with reference to this field: "Structurally, the field is dome-shaped, having a closure of approximately 350 ft. Production comes from a sandy shale interbedded with a clean sand and lying over a cap rock which is about 3400 ft. deep on top of the structure." A feature of the operation of this field is the production of the required amount of oil with the minimum of gas production. Wells on top of the dome have high gas-oil ratios, while those down structure have lower ratios, depending upon the distance of the well from the peak. To date, it has been possible to produce the oil needed from the wells circling the dome above the water zone and below the gas zone, and in this manner the average gas-oil ratio has been kept low. The gas from all separators is turned into a gas system which serves the entire field. From this system, all drilling rigs and utilities requiring gas for a fuel draw their requirements, and the remainder of the gas (about two-thirds of the production) is delivered to a compressor plant which boosts the pressure until it can be returned to the sand at the top of the dome where the rock pressure is 1400 lb, per square inch. "The Sugarland wells produce through 2-in. tubing with a 3/8-in. choke in one wing of the well-head manifold. The pressure builds up as high as 1300 lb, per square inch on the casing while on the tubing it varies from 0 to 900 lb. per square inch, depending upon the amount of gas produced with the oil."

Jan 1, 1931