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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

by their overdogmatic picture of geology and their resulting drastic oversimplification and idealization of geologic features. I am in hearty disagreement with the recommendation that geophysics should be done by cooperative work between a geologist and a geophysi-cist. That arrangement would be comparable to doing petrography by having a physicist at the microscope and a geologist sitting by his side. The interpretation of the geological significance of geophysical data can be done efficiently only by a physicist who has become also a good geologist or by a geologist who is also a good geophysicist. Less Well-trained Men The rank and file, composing perhaps two-thirds of the personnel of exploratory geophysics, is not, and should not be, composed of highly trained men. The routine, stereotyped character of the work and the impossibility of promotion of more than a few from these lower ranks even under the best circumstances justify companies in filling the bulk of these rank and file positions with men having only a bachelor's degree at the most. There can be a wide range of training for such positions, although certain lines of study are preferred for certain kinds of work, and different employers have different preferences. For work in gravitational and magnetic prospecting, first preference will be for men having geological training and second for men with civil engineering training. In seismic work, men with geological training are preferred by some employers for computers; physicists, electrical engineers and all whose technical education has covered radio circuits are preferred for the other technical positions. Collegiate training in geophysical prospecting brings no preference and by many employers is given a slightly inferior rating. One large company seldom hires men who have just graduated with a major in geophysical prospecting. This prejudice is based on the reasoning that much of what is learned in college is obsolete or obsolescent, that most of the techniques learned in college will have to be unlearned, because different from those used by the employing company, and that in the long run additional courses in basic physics, mathematics and geology are of more value to a man than the courses on geophysical prospecting. DISCUSSION [This discussion refers to the five papers beginning on page 23 and ending on page 74.1 L. W. Blau,* Houston, Texas.—I have had some rather sad experiences with forecasting. For example, I could not foresee 10 years ago my present occupation, and I do not profess to be able to look ahead 10 years and tell anyone what he will be doing then. Referring to the point raised in the discussion, I do not know, for example, what the price of oil will be 10 years from now. If an appreciable number of

Jan 1, 1940

By AIME AIME

AT A meeting of the Iron and Steel Institute held in London on May 6, Dr. J. E. Stead was formally inducted into the chair by Dr. Eugene Schneider, the retiring president. After presenting the Bessemer gold medal to Harry Brearley, of Sheffield, England, for his distinguished services to the British steel industry, Doctor Stead delivered his presidential address, a masterly review of iron and steel making progress during the past 50 years, emphasizing economy in production, and pointing out suggestions for future improvement. A considerable portion of the address was devoted to blast-furnace operation.

Jan 1, 1920

E. T. Dumble, Houston, Texas (communication to the Secretary) : During the field-season of 1890 I had occasion to examine some of the salines of eastern Texas. As the result of my stridy of them I came to the conclusion that, together with the oil of Hardin county (since extended to Beaumont by the work of Capt. Lucas) and the rock-salt and gypsum-deposits of the coast country, extending southward to the Rio Grande, these were simply a continuation of similar deposits in Louisiana described by Hilgard, Hopkins, and others; and I recommended the sinking of wells wberever they were found.

Jan 1, 1902

By William H. Spice

Exploratory drilling in South Central Texas for the year 1944 showed a marked increase over that of 1943 and resulted in a similar increase in new fields discovered. In this area, which comprises the 30 counties included in district No. I, Oil and Gas Division, Railroad Commission of Texas,? 61 exploratory wells were drilled during 1944 as compared with 29 exploratory wells drilled during 1943, or an increase of over 100 per cent. Three new oil fields, two new gas fields and one gas-distillate field were discovered during the year, as compared with one new oil field and one new gas field discovered during 1943. These new fields were the result of exploratory drilling throughout the district along the Wilcox trend and the deeper Edwards lime trend, which was started during the previous year. The Wilcox trend yielded the new Loma iilta-Wilcox oil field and the San Caja gas-* tlistillate field, both in McMullen County. The Charlotte field, in Atascosa County, was discovered along the deeper Edwards lime trend. These three discoveries were of considerable importance and subsequent development should indicate the desirability of continued exploration along these trends. The other three discoveries, United oil field in Guadalupe County, Pederson gas field in Milam County and Van Cleve gas field in Zavalla County, were of minor importance. Charlotte Field, Atascosa County, was discovered by the Humble Oil and Refining Company's No. 3 Pruitt, completcd on Aug. 9, 1944, flowing 176 bbl. per day, 3/16-in. choke, 710 lb. tubing, 475 lb. casing pressures, 37.7º A.P.I. gravity, from the top of the Edwards lime from 6917 to 6923 ft. Two oil wells were completed during the year in this field. This discovery is 14 miles southwest of the same company's Imogene field, also producing from the Edwards lime but with considerable difference in reservoir characteristics. The discovery of this field is the result of surface geology and subsequent seismograph survey of the area. Loma Alta-Wilcox Field, McMullen County, was discovered by the Atlantic Refining Company's No. I Atkinson, completed on June I, 1944, flowing 102 bbl. per day, 9/64-in. choke, 1900 lb. tubing pressure, 37º A.P.I. gravity, from Wilcox sand from 6866 to 6869 ft. after being drilled to a total depth of 7185 ft. This discovery is the result of subsurface geology and an extensive seismograph survey of the entire area. Sun Caja Field, McMullen County, was discovered by Edwin M. Jones No. 2-C Ezzell, completed on June 2, 1944 as a dual completion in the Wilcox sands, flowing 1,740,000 cu. ft. gas with 53 bbl. distillate, 1/4-in. choke, 2035 lb. tubing pressure, 53.2º A.P.I. gravity, from sand 6416 to 6453 ft. and flowing 2,000,000 cu. ft. of gas with 127 bbl. distillate, 1/4-in. choke, 2500 lb. tubing pressure, 50º A.P.I. gravity, from sand 6889 to 6916 ft., after being drilled to a total depth of 7264 ft. Three gas-distillate wells were completed during

Jan 1, 1945

By C. M. Marquardt

Tramp iron and steel moving on a conveyor belt cause small currents to be generated in a coil situated in a strong magnetic field, which are converted to an alternating current and are amplified. The output voltage from the amplifier fires a thyratron with a relay in its anode circuit, which actuates a howler and simultaneously drops a spot of marker material on the belt. THE problem of tramp iron removal from moving ore belts is a long standing one. When heavy ore streams are carried on a belt, magnetic pulleys and strong surface magnets fail to remove tramp buried in the ore stream. Tramp iron buried in the ore stream cannot be pulled from the bed by surface magnets and is carried past the magnetic pulley by the falling ore stream. With the increased use of detachable bits the problem of the detection and removal of tramp has become more necessary and difficult. Several types of tramp detectors have been developed. It would serve no practical purpose here to review exhaustively the literature on the subject. Methods of tramp detection used are: (1) The magnetic method, wherein the small current generated by the magnetized tramp passing a Coil is used. (2) The unbalanced oscillator method wherein the tank circuit of a stable radio- or audio-frequency oscillator is unbalanced causing a change of frequency or a change in plate current due to changes in eddy currents, hysteresis, or dielectric because of the presence of tramp. (3) The bridge methods wherein the impedance of one leg of an alternating current inductive bridge is changed due to the presence of conducting tramp. Each of these methods of tramp detection has its field of usefulness. The second and third methods are excellent for oxide iron ores, coal, sand and gravel, grain, etc. However, these latter methods are not suitable for use on ores that contain rich conducting sulphides, since a large piece of pyrite or galena will cause the same detector response as a piece of tramp iron. At the Caselton, Nevada, plant of the Combined Metals Reduction Co., sulphide ores are treated; therefore, it was necessary that a tramp detector operating on only the magnetic properties of the tramp iron be used. Tramp iron detectors of this type operate on the principle that if a piece of tramp iron moves near a coil in a high intensity, steady magnetic field, the presence of the moving tramp iron causes the magnetic flux lines through the coil to change. This induces a mall current in the Coil. In series with the Coil is generally placed a relay sensitive to currents of 1 to 3 microamp. When the tramp iron passes near the coil the flux linkages change, causing this very sensitive relay to actuate. Since the contacts of such a relay are very small it must actuate a second relay capable of breaking a larger current

Jan 1, 1951

By T. I. Harkins, J. Brian Eby

This paper outlines the geophysical investigation of the area covering the D arrow salt dome, Louisiana. Surveys with the refraction seismograph and torsion balance failed to disclose the dome, but reflection dip shooting was successful and was confirmed by later drilling. Introduction The D arrow salt dome and oil field lies in western Ascension Parish, Louisiana, on the outside of a sharp bend and on the east bank of the Mississippi River. The dome occurs about 30 miles south of Baton Rouge and 80 miles northwest of New Orleans. Its geology, shape and structure have been ably described in detail by Carroll E. Cook' and, except for the general features, will not be repeated here. The purpose of this paper is to record some of the interesting and pertinent geophysical data contributing to the discovery of the dome and eventually the oil field. The salt dome is circular in outliie and comes to within about 4625 it. of the surface. At this depth the diameter of the salt plug is approximately 4800 it. The dome has only a thin cap rock of less than 75 ft. Some oil has been found and is being produced in Miocene sands above the cap rock, but most of the field's production comes from a narrow ring of wells around the east and south flanks of the dome. Producing horizons on the flank are found at 5670 to 5840 ft. in the Miocene and 6890 to 6985 ft., 7028 to 7060 ft. and 8260 to 8270 ft. in the Oligocene. The deepest well that has been drilled is the Humble Oil and Refining Company's Community B-5, on the south flank of the structure, which reached a depth of 10,013 feet. The size and shape of the field and the area of production are indicated on Fig. I. The lie showing the area of production encloses all wells now producing and all abandoned producers, both on the top and flank of the dome. This line of production is shown on all subsequent geophysical maps as a direct means of comparing the early geophysics to later drilling development. Darrow dome occurs on the low, flat flood plain of the Mississippi River; it is protected from flood overflow by high artificial levees. The rich loamy soil supports a high degree of cultivation, principally sugar cane. Drainage is secured by many small canals and the water table of the area is at or near the surface. These particular conditions of topography, drainage and top soil greatly influenced the early geophysical picture, and the influence was always unfavorable.

Jan 1, 1946

By James A. Crookston, William D. Fitzpatrick

Committee C-8 of the American Society for Testing and Materials defines "Refractories" as "Material, usually nonmetallic, used to withstand high temperature," and it defines the term "Refractoriness" thus, "In refractories the capability of maintaining the desired degree of chemical and physical identity at high temperatures and in the environment and conditions of use." The ability to withstand high temperatures is critical to classifying a material as a "refractory." However, as the foregoing definition of "refractoriness" implies, the refractory material may be subjected to and is expected to resist not only high temperatures but a variety of other destructive forces incident to its use. These include abrasion, impact, thermal shock, chemical attack, and high level loads at high temperatures. The various industrial applications of refractories represent an infinite variety of combinations and degrees of severity of these destructive forces, including high temperatures. Naturally, such a variety of application conditions leads to a need for a wide variety of refractory products to satisfy those conditions. The number of refractory products available is great enough that some form of classification is necessary to a discussion of refractories. Refractories may be classified in several ways, but the most suitable one is based on their general compositions and to lesser degrees on their physical condition and distinctive properties. The primary types of brick include aluminosilicate brick (fire clay and alumina), basic brick (magnesia and chrome ore, alone and in various combinations), silica brick, insulating brick, and special refractories (carbon, Sic, ZrO,, zircon, borides, and nitrides). Brick are, of course, preformed and are usually heat treated at high temperatures before use, but are in some instances unburned and/or chemically bonded, including the relatively new class of tar-bonded magnesia and/or dolomite brick. In addition to preformed refractories, another broad category includes the so-called specialty refractories, which are usually made in the same types as itemized for brick-bonding mortars and high temperature cements, hydraulic setting castables or refractory concrete, plastic firebrick, and ramming mixes. Refractory grains, such as fire clay and high alumina calcines, dead-burned magnesite and periclase, and dead-burned dolomite are also considered refractory products. Brick are also classified on the basis of physical dimensions, as standard sizes and special shapes. The standard sizes are those which are of definite shape and design and are designated as 9 x 4 ½ x 2 ½ in. and 9 x 4 ½ x 3 in. straights and series. All other brick of non- standard sizes are referred to as special shapes. These come about as a result of a particular need for a given furnace or for a particular application.

Jan 1, 1975

By J. Brian Eby, T. I. Harkins

This paper outlines the geophysical investigation of the area covering the D arrow salt dome, Louisiana. Surveys with the refraction seismograph and torsion balance failed to disclose the dome, but reflection dip shooting was successful and was confirmed by later drilling. Introduction The D arrow salt dome and oil field lies in western Ascension Parish, Louisiana, on the outside of a sharp bend and on the east bank of the Mississippi River. The dome occurs about 30 miles south of Baton Rouge and 80 miles northwest of New Orleans. Its geology, shape and structure have been ably described in detail by Carroll E. Cook' and, except for the general features, will not be repeated here. The purpose of this paper is to record some of the interesting and pertinent geophysical data contributing to the discovery of the dome and eventually the oil field. The salt dome is circular in outliie and comes to within about 4625 it. of the surface. At this depth the diameter of the salt plug is approximately 4800 it. The dome has only a thin cap rock of less than 75 ft. Some oil has been found and is being produced in Miocene sands above the cap rock, but most of the field's production comes from a narrow ring of wells around the east and south flanks of the dome. Producing horizons on the flank are found at 5670 to 5840 ft. in the Miocene and 6890 to 6985 ft., 7028 to 7060 ft. and 8260 to 8270 ft. in the Oligocene. The deepest well that has been drilled is the Humble Oil and Refining Company's Community B-5, on the south flank of the structure, which reached a depth of 10,013 feet. The size and shape of the field and the area of production are indicated on Fig. I. The lie showing the area of production encloses all wells now producing and all abandoned producers, both on the top and flank of the dome. This line of production is shown on all subsequent geophysical maps as a direct means of comparing the early geophysics to later drilling development. Darrow dome occurs on the low, flat flood plain of the Mississippi River; it is protected from flood overflow by high artificial levees. The rich loamy soil supports a high degree of cultivation, principally sugar cane. Drainage is secured by many small canals and the water table of the area is at or near the surface. These particular conditions of topography, drainage and top soil greatly influenced the early geophysical picture, and the influence was always unfavorable.

Jan 1, 1946

By G. W. Lester, T. J. Nowak

The paper presents a practical method of utilizing pressure fall-off data obtained when a water injection well is shut in for determination of: (I) the static reservoir pressure, (2) the potential water injective capacity (md-ft) of the formation, and (3) the formation damage (skin effect) surrounding the wellbore. In the development of the method, equations are presented which give The theoretical background for predicting the behavior of water injection wells. Certain physical factors which limit the application of the method are discussed. The procedure and the relevant precautions in obtaining the data are discussed. A sample analysis and computation from an actual pressure fall-off curve is illustrated. Fintrlly, general characteristics of pressure fall-off curve! obtained in several reservoirs are presented. INTRODUCTIO N Theoretically, in an injection well the flow of water into the formation will continue as long as the sand-face pressure is greater than the reservoir pressure. However, in practice, engineers have observed that upon stopping injection and opening the wellhead to atmospheric pressure, some wells backflow water for time intervals ranging from several seconds to several hours although the sand-face pressure, as calculated from the hydrostatic head, is considerably greater than the static reservoir pressure. Further, field observations indicated that upon shutting in a water input well, the wellhead pressure does not drop off immediately, but a pressure decline occurs lasting from several seconds to several days. These observations make it evident that when an input well is shut in, a residual pressure lingers in the vicinity of the wellbore which is greater than the average reservoir pressure. This residual pressure declines first rapidly, then more slowly, to the static reservoir pressure: therefore, it is called transient back-pressure or pressure fall-off. The first step in investigating the mechanism of pressure fall-off is to establish what general conditions are necessary for its occurrence, and to this end, Dickey and Andresen1 have presented a qualitative explanation describing the mechanism. They point out that the formation pressure gradient in the vicinity of the well does not disappear immediately when the input well is shut in, as if the system were filled with a totally incompressible fluid, but it is maintained by the expansion of the compressible fluids and by the elasticity of the formation. In such a compressible system the decrease in pressure is possible only to the extent that the water front continues to advance until the pressure is equalized. The principal aim of this paper is three-fold; namely. (1) to present a theoretical quantitative analysis of pressure fall-off data, (2) to present an application of the developed theory to field data, and (3) to discuss the general characteristics of actual pressure fall-off curves. Under (I), theoretical equations dealing with such factors as compressibility of the fluid-reservoir system, mobility of the fluids and certain physical restrictions that

Jan 1, 1956

By G. C. Weaver, G. T. Harley

Beds or lenses of potash and magnesium salts are found in a thick salt section (Salado) overlain by Rustler Red Beds in several members of which water is present and from one of which the rehery process water used by International is obtained. Most of the holes drilled are less than 1000 ft. deep, but some wildcat holes have exceeded 3- ft. cable or rotary tools are used to drill down to the salt. when samples of water are desired the cable rig is used, but when this is not necessary, and where caving material is present, the rotary rig has an advantage. The rotary rig has a further advantage in that only one machine is required to drill and core the entire hole, whereas the cable rig must be moved off to make way for the core drill. Casing is placed in the upper section of the hole as required to shut off water, and a 5 3/16 in. string is set in the top of the salt before coring starts. With the rotary rig drilling is often carried to the salt with no casing, as drilling mud seals off caving ground and water-bearing strata, and a string of 4-in. line pipe or 4-in. flush-joint casing is landed on top of salt. Several types of gasoline-powered core rigs have been used in the field and all recover a 2 1/2-in. core. More recently the Sullivan Model 37 rotary rig has been tried, and a Sullivan Model N has been adapted to use a rotary bit in the upper section. Core is recovered in 20 ft. sections with a double-tube core barrel, and the bit used is a bottom-discharge type set with diamonds. The drilling fluid must be a saturated brine to prevent solution and etching of the minerals present. Blowouts are apt to Occur from nitrogen gas trapped under the several polybalite beds, and some have been strong enough to blow the tools out of the hole. Core recovery is practically loo per cent. All holes are plugged after drilling, with cement through the salt section and opposite each water horizon* and mud through the remainder of the hole. Cores are carefully logged and preserved, and in sections containing potash and magnesium minerals they are quartered and analyzed. The correlation of Ore beds between drill holes is briefly described. Introduction Beds Or lenses of potash and magnesium salts are found at varying depths in a thick deposit of salt (Salado formation) in what is known as the Permian Basin, in southeast New Mexico and West Texas. The Salado formation is Composed chiefly of common salt (halite) with numerous beds of anhydrite, polyhalite, and the soluble potash minerals carnallite, sylvite and langbeinite. Many other minerals are present in small amounts but their Presence has no bearing On the coring technique. Before starting to core the salt section it is necessary to penetrate 300 to 600 ft. of unconformably overlying Permian sediments (Rustler formation) which are composed of red and gray clay, sand, anhydrite, dolomitic limestone and occasional lenses of salt. The upper part of the formation is predominantly anhydrite, and the lower part predominantly clastic. A thin bed of dolomitic limestone, known

Jan 1, 1948

History of Reverberatory Smelting in Montana, 1879-1933. By FREDERICK LAIST (Trans, vol 106 31,800 words ) The development of the art of reverbera¬tory smelting from 1879, when smelting first started in Butte, up to the present time is described. The paper traces the development of the reverberatory furnace, as regards both constructing and operating, from the initial 10-ton furnaces to the present-day 600-ton furnaces and the changes in operating practice which accom¬panied the gradual enlargement of the furnaces and the reasons therefor are described and explained The results obtained from an investigation (made in the course of the Carson litigation) into the various methods of charging reverberatory furnaces are given These investigations proved that the method of charging a reverberatory had very little to do with its performance It was also found, at the same time, that the depth and extent of the bath maintained in the furnace had very little to do with its performance Numerous operating results are included and the article is illustrated Development of Copper Converting at Butte and Anaconda. BY WILLIAM KELLY AND FREDERICK LAIST (Trans , vol 106 4400 words.) This paper is based on recollections of one of the authors, W M Kelly, who has been identified with the development of smelting and converting at Butte and Anaconda since early times The article starts with a description of the circumstances surrounding the first intro¬duction of copper converting at the Parrot Works in Butte under the Manhes patents It briefly recounts the difficulties which were encountered and the steps taken to overcome them Among these were the absence of means for punching tuyeres in the original converter This difficulty was overcome crudely by drilling holes in the windbox opposite the tuyeres, said holes being closed by wooden plugs Later these plugs were replaced by steel slides and still later by the Dibblie ball valve, which has remained standard ever since The development of the converter from both struc¬tural and operating standpoints is traced from the early beginning to the present day Developments in Lead and Copper Converting at Tooele. BY B L SACKETT (Trans, vol 106. 3900 words) This paper shows the development at this Utah lead and copper smelter from separate converting of the two kinds of matte produced to a more efficient and economical treatment of the combined mattes This was accompanied by the use of relatively large amounts of silicious ore in the converting of lead matte as well as copper matte, which greatly improved the quality of converter slag produced, both from the standpoint of its copper content and its desirability for

Jan 1, 1935

By Ronald W. Klusman, Erik B. Nelson

The Front Range portion of the Colorado Mineral Belt is an extensive area of mineralization with mining activity dating from 1859 with the discovery of large gold deposits. After an initial boom period and gradual diminishing production, present activity is restricted to molybdenum in Clear Creek County, uranium in Jefferson County, and several small operations extracting gold and silver in Clear Creek and Gilpin Counties. Gold and silver have dominated the production in the Front Range, though the complex mineralization created milling and smelting problems and it is postulated that considerable amounts of precious metals remain in the mine dumps. This area is plagued by a severe mine drainage problem, with Clear Creek most impacted by many draining mines and tailings in the basin. Boyles et al. Moran and Wentz, Wentz, Wildeman et al., have examined various aspects of the impact of mine drain¬age in the Clear Creek basin. The primary objective of this study was to collect data on the tailings, drainages, and leaching experiments in order to make preliminary suggestions for reducing the impact while recovering metal values to offset treatment costs. A variety of leaching experiments were performed on tailings from the Nevada Gulch area in the Central City mining district. Leachings were performed in vertical tubes indoors and wooden boxes exposed to the outside environment. In the leaching experiments, the leaching solution, grain size, and residence times were varied, while forced aeration was used in some experiments. Bacterial nutrient 9K° and mine drainage were used in some of the experiments. A total of 14 additional tailings samples were analyzed for base and precious metals. The composition of the mine drainage and tailings used in the leaching experiments, as well as data on the additional samples are shown in [Table 1]. Leachate samples were taken periodically for analysis until compositions leveled off. Results and Discussion Leaching with distilled water was used as a control and best illustrates the basic behavior of the leaching process for zinc in a vertical tube [(Fig. 1)]. More acidic leachings increased concentrations of metals as did smaller grain sizes, though the time required increased significantly. Mine drainage with its high concentration of dissolved iron sometimes decreased the heavy-metal concentration in the leachate due to oxidation of Fe 2 and precipitation of Fe(OH)9 which absorbs some of the dissolved heavy metals. In the larger scale experiment carried out in the simulated leaching pad, substantial concentrations of metals were attained in the final leachate after one month. In this experiment the leachate was not recycled, but allowed to saturate the tailings continually with evaporation loss made up by additions of Quartz Hill drainage and nutrient 9K. The concentration of the metals in the leachate and the increase over the input solution are given in [Table 2]. Heap leaching of low-grade copper and uranium ores is successfully carried out in many districts, enhanced by the metabolism of autotrophic bacteria of the Thiobacillus-Ferrobacillus group. These ubiquitous organisms enhance metal leaching, and general aspects of heap leaching are discussed by Malouf, Trudinger, Pings, and Duncan et al. Conclusions and Recommendations Returning to the primary objective, how to reduce the mine drainage impact and recover metal values, we need to consider how the data may suggest avenues toward this objective. Boyles, et al., considered various

Jan 1, 1977

By S. I. Liu

THE effects of strain histories, consisting of several prestrains in opposite directions, on the flow and fracturing characteristics of metals determined in a final test have been investigated previously.'" Such strain histories vary from a single prestrain in tension or compression to the number of strain cycles leading to fatigue failure.' Between these two limits, various strain histories could be visualized and some can be attained readily. One such example is a strain history consisting of a first prestrain in tension of various magnitudes and a second prestrain in compression also of various mag-nitude. In this investigation the strain history was extended to the combination of these two limits, i.e., a single prestrain in tension or compression followed by balanced strain cycles of a selected magnitude e, = k0.12. It was found in this case that only compressive initial prestrains could be investigated with sufficient accuracy.* Such strain histories can be considered also as (low cycle) fatigue tests of a metal subjected to various amounts of cold working. It appears from previous publications that cold working within a wide range of reductions usually raises the un-notched fatigue strength of many metals.'-' This effect, however, has been found to be inconsistent and sometimes reversed for other metals?.7 Furthermore, Ludwik reports that the yield strength of cold-worked specimens may be reduced by cyclic strains, while that of materials without cold work is generally increased in the initial cycles." " In addition to the above tests, a study was made of the effect of intermediate re-solution heat treatment on low cycle fatigue behavior. Such anneals should eliminate the strain hardening induced by the cyclic strains. As far as their effect on the fracture characteristics is concerned, a few previous tests seemed to indicate that the damage resulting from cyclic strains is retained only partially after heat treatment." A further investigation was made in which one specimen was subjected to repeated unbalanced tension cycles in which the strain interval was approximately $ 0.013. This repetition of plastic tension damages the material slightly. This result appears to confirm Ludwik's observations." " Commercial 3/4-in. rod of the aluminum alloy 24ST4 was selected for this investigation. The material was subjected to the following treatments before machining: 1—Re-solution treatment at 920" ± 10°F for 45 min, 2—water quench at room temperature, and 3—aging for four days at room tem-perature.? The treated material then was machined to desired specimen contour and tested. A coolant was used during machining to minimize any artificial aging effects of heating during machining. In some cases the 24ST4 specimens were reheat treated after having been strained. In these cases, the heat treatment was the same as the re-solution heat treatment described above. Procedure As shown in Fig. 1, threaded end specimens with a minimum diameter of 0.266 in. and a contour radius of 2 in. were used for prestraining to an axial compressive strain ranging from 6, = —0.10 to E, = —0.48. For large prestrains, two consecutive corn-

Jan 1, 1952

By W. M. Mobley

THE coal industry in Alabama, centered in Birmingham, has pioneered coal-beneficiation practice in the United States. The nature of the coal seams and mining methods employed have necessitated use of equipment and methods best adapted to the local conditions. Although all of the 30 or more coal seams now being mined in the state receive beneficiation, only the three most important producers of coking coals, the Pratt, Mary Lee and Black Creek, are discussed in detail. Nature of the seams, washability characteristics and equipment used are given as examples of the extent of work and progress in this field. The coal seams in Alabama are relatively thin and pitching, making mining difficult and expensive. Most of them are characterized by thin partings of rock or shale in the seam itself, as well as laminations of bone and rash. Mechanical mining methods have increased the occlusions from roof and floor to such an extent that nearly all the coal mined in the state must receive some treatment before it can be put on the market. During the year ending Sept. 30, 1943,1 18,129,792 tons of coal were mined in the state and 14,364,177 tons, or 79.2 per cent, received treatment. Excluding from the total the 1,223,014 tons produced by small wagon mines and the hand-picked lump coal, the amount receiving beneficiation would be more than 90.00 per cent. This is, by far, greater than in any other coal-producing state. The earliest record of coal beneficiation in Alabama was the installation in 1890 of an experimental Lung washer by Alexander Cunningham, for the Sloss Iron and Steel Co. at its blast furnace in Birmingham .2 In 1894 the Jeffrey Manufacturing Co. introduced the English Robinson washer, a combination of a hydraulic classifier and centrifugal machine. Erskine Ramsay, who has contributed so much to the coal industry, saw its possibilities as well as its mechanical defects and soon had his inventive mind at work. He added a sludge tank of his own design, and many Robinson-Ramsay washers were installed in Alabama and other states. The Stewart jig appeared in 1900, followed by the Montgomery jig in 1910 and both have found extensive use. Increased interest in this field led to new designs, such as the American, Elmore; Burke and Faust. The first Baum-type Norton jig was operated in 1930 and within the last five years six large installations of this type have been made by the McNally-Pittsburg, Jeffrey and Link-Belt Companies. Wet-washing tables were introduced in 1922 but not extensively used until recently. The two most popular types are the Deister-Overstrom and Deister Plat-O. The coal-cleaning equipment used in Alabama has been relatively simple, yet efficient, but as the amount of impurities in the raw coal has been increased by mechanical mining and labor costs have become higher, much interest has been shown in sand cones, froth flotation and

Jan 1, 1945

By W. K. Hardy, H. H. Stadelmaier, L. J. Huetter

The ternary system Co-Sn-C was studied in the cobalt-rich region. The liquidus projection ulas established and two fonr -phase reactions were found. An isothermal section at 950°C was worked out. In the region studied the following phases were observed: cobalt-rich solid solution, graphite, binary compound y -cobalt-tin, and a ternary compound. As a result of the limited solubility of carbon in liquid cobalt-tin alloys, the investigation was limited to the cobalt-rich region. Tin contents up to 32 at. pct were studied. Cobalt of 99.99 pct purity, tin of 99.97 pct purity and synthetic graphite of 99.93 pct minimum purity prepare the alloys. Carbon determinations of all alloys were obtained by gas volumetric analysis. Samples were investigated microscopically and by X-ray diffraction using CoK, and FeK, radiation. Cooling curves were obtained with a number of alloys to determine the temperature of the four-phase reactions. The thermocouple was calibrated with the melting points of high-purity silver and copper. In the region studied the following phases were observed: Cobalt-rich solid solution (face-centered cubic) Graphite. Binary compound y (solidifies congruently at composition Cop~n)'. Ternary compound k which is face-centered cubic with superlattice and nonferromagnetic.' In Fig. 1 the fields representing the projections of the liquidus surfaces were determined by microscopic investigation and are labled by their primary phase. In the field labled C graphite is the primary phase. During solidification in this field much of the primary graphite was expelled through the surface of the melt. It could not always be established microscopically whether the remaining graphite was primary or purely eutectic. Therefore it was not possible to determine accurately the boundary curve which drops from the binary eutectic el at 1309 "~~ to the point of the four-phase reaction at F. The ter-nary carbide is the primary phase in the field labled k. To the right of this field the primary graphite is consistently nodular whereas flake graphite is observed at tin contents somewhat below F. The ternary carbide does not appear to solidify congruently. The graphite is attacked in a peritectic reaction along the boundary between k and C. Thus no graphite is observed in alloys in the k field. In alloys right of the boundary between k and C the graphite nodules are located in the center of the k crystallites, further documenting the peritectic nature of the reaction with the graphite. A four-phase reaction was found at F and 1120 &3"C. The most likely reaction is L+ CY-Co + C — k. Below the temperature of the binary eutectic ez at 1112" a second four-phase reaction was observed at E and 1100 lt3"C. It is the ternary eutectic L — CY-Co + k + y. Figs. 2(a ) to (e) show microstructures of the ternary alloys in the as-cast condition. Fig. 2(a) shows the eutectic a-Co + C (with some primary graphite) with the carbide k in the grain boundaries. Fig. 2(b) shows primary cobalt (dark areas) and the eutectic a-Co + k which is formed along F-E.

Jan 1, 1961

By H. Papazian, Robert A. Lad

SINCE it can be shown both theoretically'' : and experimentally that disordered Cu3Au has a greater internal energy than the ordered alloy, it might be expected that its chemical reactivity would be greater. Experiments were initiated' to test this hypothesis. This note will describe some recent results obtained in the study of the rates of corrosion of ordered and disordered polycrystalline Cu3Au by aqueous FeCl., The work of Robertson' has indicated that the attack by such solutions is intergran-ular and highly orientation dependent. It was of interest to see whether the order-disorder effect was great enough to overcome the variations from specimen to specimen which would arise from this type of attack. The polycrystalline alloy specimens (0.020 in. wire, 1¾ in. long) were preannealed in ½ atm H, at 700°C for 2 hr. The subsequent heat treatments to produce order and disorder were performed in M atm He. Disordered specimens were obtained by heating at 450°C for 2 hr and quenching in water. Ordered specimens were produced by heating for 2 hr at 450°, furnace cooling to 380°, and soaking at 380°C for 80 to 90 hr. Room temperature was reached by cooling to 150" at a rate never exceeding 7" per hr, and water quenching from 150°C. The specimens so produced exhibited electrical resistivities characteristic of the two states; of the order of 11.27x10 ohm-cm for the disordered, and 4.28x10 ohm-cm for the ordered specimens. The corrosion rates were studied at 30°C in ferric chloride solutions of several concentrations (?,¼, 1.5, and 1 molar). The specimens were attached to a stirrer during the tests. Tests were interrupted at intervals, and the specimen weight change was determined after washing and drying. Analysis of the solutions showed that the attack was limited to the copper. The higher corrosion rate for the disordered alloy, as illustrated in Fig. l, is typical of the results obtained. The effect of variation in ferric chloride concentrations is indicated in Table I for typical specimens. The variations in the ratio of reactivity for disordered and ordered specimens at the different concentrations are within experimental error, and the best value is estimated to be near 1.4. The experimental variation was due in part to the mode of attack, as mentioned, and in part to the fact that films were formed on the specimens under some conditions. Electron diffraction patterns of the films were very complex and indicated the presence of metallic iron, as did chemical analysis. In an attempt to eliminate the difficulties arising from the mechanism of attack, single crystal specimens were used. A greater reaction rate was again measured for the disordered specimens, but the reproduci-bility was no better than that for the polycrystalline metal. This would indicate that film formation was primarily responsible. It was concluded that the reaction with aqueous ferric chloride served to demonstrate that the reactivity of disordered Cu3Au is greater than that of the ordered alloy. However, the difficulties with film formation did not permit determinations of a precision great enough to warrant extension of the study to partially ordered alloy systems.

Jan 1, 1957

By Walter Dake

THE mining engineer is being more generally called on to examine and report on properties where the introduction of mechanical loaders is proposed, and as the use of these labor-saving devices presents an entirely different problem from that of hand-loading, an outline of procedure is herewith pre¬sented based on five years of intensive field experience in making such studies. It is impossible to outline an examination which will cover every condition but the most important variables are noted and the re¬port may be amplified or abridged to suit individual mine requirements. There are, of course, exceptional cases in which a single minor variable will determine the final conclusion; the result of mechanical loader application can be, estimated within close limits by considering all variables listed and taking into account the sum of all those found to be applicable to the property under examination. It is necessary that a high degree of accuracy be exercised in the analysis of conditions, and that a relatively narrow margin be figured on all estimates of tonnage outputs and costs. In making an examination for this purpose the data as to company name, business address, name of mine, geographical location, rail or water connections, type of mine (whether shaft, slope, or drift), and the name of seam should, of course, be included, to be followed by the minimum, maximum, and average thickness of seam, a brief description of the charac¬teristics of the coal, the impurities contained, location of regular impurities or partings, together with nota¬tion as to quality, uses, and-markets for the coal. It is also necessary to make cross-sections of the seam so that face preparation may be studied in an effort to eliminate all regularly-occurring impurities at the working place. The possibilities for further cost re¬ductions by the removal and gobbling of partings under¬ground before mechanically ? loading out a face are sufficiently great to warrant careful study and analysis. The classification of the mine from the standpoint of gaseous or non-gaseous operation will determine the general type of electrical equipment needed. A notation regarding the power whether generated at the mine or purchased, together with the amount, voltage, and type of current available is necessary since these matters determine the exact type of elec¬trical equipment to be used. A brief description of the ventilating system, giving type of fan, amount. of air delivered, water gage, and whether force or ex¬haust type, will enable the engineer' to figure venti¬lating requirements per man under mechanical loading practices. The pitch of seam in degrees, the pitch of working faces, and a brief description of rolls or horsebacks should be included, as these affect the efficiency of mechanical loading and, therefore, the economic re¬sults obtainable. -Notations should be made as to the amount of water found in working faces, and whether pumping, sprinkling or rock-dusting methods should be considered. As the character of the floor affects the operation of the machine at the face if a cater¬pillar-tread type, its hardness should be determined, and also whether impurities consisting of floor ma¬terial are likely to be loaded with the coal. The char¬acter of the roof and overlying stratification determine the mining system and width of roof span at work¬ing faces. It therefore directly regulates the amount of tonnage to be loaded by machines without a move from one place to another.

Jan 12, 1927

By F. B. Plummer

THE practice of introducing acid into oil wells to increase production of oil and gas has been in use since 1894, when it was first used in the Pennsylvania. oil fields30.? It is only since 1928 that it has been used to any extent in the Mid-Continent18. The process has proved successful in increasing production, at least temporarily, in depleted oil fields where the producing formation is highly calcareous and where water drive is not too pronounced. In the Zwolle field in Louisiana, where the producing horizon is a chalk, increases of 100 per cent have been recorded25. In north-central Texas, where the oil is produced from the Marble Falls limestone, equally pronounced increases have resulted3. The production also in some fields yielding oil from quartz sand cemented with calcite has been benefited. The evidence of actual increase in total recovery of oil, however, has been questioned by some engineers18. It has been pointed out that the results of the treatment of a well in a new district, where the process has never been tried out, can never be predicted with certainty, since other factors besides percentage of calcareous content: of the oil sand play a large part in determining the success of the method. Numerous articles have been published on acid treatment and on the effects of acid on limestone1-35, yet very little has been written con-cerning experimental work on the actual effect, of acid on capillary pores and larger oil-coated voids of oil sands. This is due partly to difficulties in duplicating field conditions in a laboratory and partly to the fact that the process has been carried out largely by contracting companies that have been unwilling to publish details of their results for fear of loss of business to competitors. The authors, using equipment developed to measure the radial permeability of oil-sand cores29, have developed a method of investigating the results of acid treatment which has enabled

Jan 1, 1935

ALTHOUGH iron ores occur in many parts of Sweden the two principal deposits are those at Grängesberg (see accompanying map) and at Kiirunavaara-Gellivare. Both of these deposits are con-trolled by a holding company, Trajikaktiebolaget Grängesberg-Oxelösund, which sells annually about one-half of, the iron in ore traded in world markets and has a fleet of 24 seagoing ore boats, with a total dead weight capacity of 172,500 tons. Because of its pre-eminence in international iron ore trade a brief outline of its operations will be of interest. ORE DEPOSITS OF GRÄNGESBERG The Grängesberg deposits have been known since the Middle Ages, but up to the middle of the nineteenth century the ore was transported from the mines to the furnaces in winter in. sleighs. Railway building began in 1853, and in 1873 the complicated structure of capital investment was tottering, but the basic bessemer process created a demand for ore high in phosphorus, as this is, and refinancing on the initiative of Sir Ernest Cassel put the principal operation on a firm footing. There are numerous property owners in the district, but they are all controlled by a joint administration board, and 90 per cent of the ore is produced by a subsidiary of the Grängesberg company from proper-ties which it either owns or leases. The ore, a mixture of magnetite and specular hematite, is in lenticular bodies, dipping about 70 E. in. fine-grained gneiss, and contains about 61 per cent Fe and 1 per. cent. P. There are two principal veins; the total ore reserves to a depth of 500 meters are estimated at 150,000,000 tons. As seen in the accompanying illustration, the ores were first worked in open cuts, but eventually underground shrinkage stoping was adopted. Difficulties were encountered in the support of the workings and from the freezing of the ore in the stopes, so slicing was adopted, although block-caving is used in one place. Most of the mining is now done at a depth "of 150 to 190 meters. The present annual output is about 1,400,-000 tons of crude ore, which yields about 1,000,000 tons of concentrate after being subjected to magnetic con-centration and jigging.

Jan 1, 1927