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By K. A. Kiselev, V. I. Zelentsov, V. P. Nebera

INTRODUCTION Most works on flotation of ions and precipitates from solutions have been summarized recently (1-3). Flotation is more desirable than thickening or centrifuging because of higher recovery, productivity, simplicity of apparatus and better economics in general. Electrolytic flotation that utilizes gases is more favorable than other flotation processes because of the following: higher dispersity of gas bubbles, low coalescence of the bubbles, possibility of gradual regulation of the dispersity and other parameters of flotation (4-5). Flotation from solutions is mostly based on the use of alkaline reagents as precipitants (5). Flotation from acid solutions is less common. We used multicomponent solutions with more than 2-3 components, unlike previous research methods. Acidic flotation allows recirculation of solutions to previous operations such as leaching, etc. REAGENTS FOR PRECIPITATION Electroflotation was studied over a wide range of pH with the addition of ferrocyanide, oxyquinoline, hydroxide and carbonate precipitants. In recent works (1,2,6,7) on flotation of Ni, Cu, Zn from alkaline solutions, mostly ferrocyanides were applied. Our choice was oxyquinoline because of the following: 8-oxyquinoline is a nonspecific reagent for many metals, it is readily soluble in acids and alkalis, oxyquinolates of the studied metals are in soluble compounds, the reagent works over a wide range of pH, it is widely available, oxyquinolate precipitates are stable when exposed to air, are readily floatable, and are easily converted to oxides of the metals by sintering.

Jan 1, 1980

By H. R. Hanley

ONE of the most important contributions to the art of electrolytic zinc production-has been the aluminum cathode. This has been used in all major production: since its commercial development in 1916. The literature is replete with important contributions, some of which may have been replaced by better ones, but thus far there appears no other metal to take the place of aluminum as cathode material. Credit for this innovation goes to Sherard Cowper Coles, of England. When experi-menting on the extraction of-zinc from Broken Hill ore at Hayle, Cornwall, in 1893, he introduced the aluminum cathode, and in 1895 obtained British Patent-No. 20073. The reason for this dominant position of aluminum as cathode mate-rial in zinc sulphate electrolytes is its unique surface, to which electro-deposited metals usually do not tightly adhere. The metal must be of high purity for best results. It is possible to develop a starting-sheet method by which thin electro-deposited sheets of cathode zinc are made and stripped from a smooth aluminum plate. Such thin sheets of cathode zinc may be used as arc tine copper sheets in standard electrolytic copper-refinery practice. However, complications arise because of extreme warping of the zinc starting sheet after a .few hours of deposition, and thus special arrangements must be made to compensate for this abnormality.

Jan 1, 1938

By E. R. Palowitch, P. H. Broussard

The United States aims to achieve some modicum of energy self-sufficiency through means such as conservation, increased domestic oil and gas production, substitution by the electric utilities of coal or coaloil mixtures for oil and gas, and development of a viable synthetic liquid fuels industry. Coal's role in attaining this goal will necessitate doubling coal production by the end of the 1980's. And if the United States does in fact become the World's Saudi Arabia of coal, the total annual production to meet these domestic needs and export markets could double again by the year 2,000. As only a small portion of our Nation's reserves are recoverable by state-of-the-art surface mining methods, most of the coal produced in the future will have to be mined underground (Averitt, 1975). But this projected increase in coal demand is occurring in the face of a decade of radically decreasing productivity. Specifically, average worker productivity in underground coal mines has decreased from 14.2 tonnes (metric tons) per workershift in 1969 to 7.2 tonnes per worker-shift in 1979; and 95 percent of coal produced underground during this period was produced by room-and-pillar methods (U.S. Dept. of Energy, 1980). Although there is no complete agreement on the impact of recent Federal legislation, there is strong correlation between the dramatic decrease in productivity in underground coal mining and the implementation of the recent Federal mine health and safety regulations (U.S. Congress, 1969). A review of the wide range of coal mining research, development, and demonstration projects currently being funded by the federal government and by industry gives little encouragement for increasing worker productivity on room-and-pillar sections underground in the immediate future (Palowitch, 1978). Conversely, the opportunities for increasing production/productivity underground with longwall methods appear somewhat more encouraging. Although at least one longwall face in the U.S. did produce more than one million tonnes of coal in a single year, the national two-shift average production from one hundred or so longwall faces is about 1,000 tonnes per day (Huwood-Irwin Co., 1978 and Consolidation Coal Company, 1976). Clearly, there exists some real opportunities for improvement. One of these opportunities is to automate the cutter-loader.

Jan 1, 1981

By C. P. Besse, N. F. LeBlanc

Described in this paper are oceanographic data which should be considered by an offshore design engineer and methods for developing a design wave height from the oceanographic data. The selection of a design wave is predicated on contemplated waves which might affect the site throughout the life of the structure. Selection of a design wave height may be based on (1) arbitrarily established recurrence Frequencies of hurricanes affecting the structure (predicted wave heights are associated with the expected variations of forces resulting from these waves) and (2) a risk-type evaluation wherein all possible storms affecting the area are considered (anticipated wave heights are associated with both investment plus risk costs and expected variations of forces). It is shown how the following oceanographic predictions are integrated into design considerations: (1) a classification of storm intensity which considers all recorded storms which affected the design area, (2) the recurrence interval of storms of a given- intensity (this interval is dependent on the extent of the geographical area considered in the design problem) and (3) a forecast of all wave heights which might affect the area (geometry of a structure often necessitates consideration of waves from a multiplicity of directions). The authors believe that the described techniques can result in selecting an adequate and reasonable design wave. INTRODUCTION Since the inception of offshore operations in the Gulf of Mexico, engineers engaged in designing suuctural facilities have been plagued with the problem of selecting an adequate and reasonable design wave. In the development of any offshore structure it is mandatory that the engineer evaluate the ability of the structure to withstand the ocean waves to which it will be subjected. Selecting such design waves quite naturally necessitates a coalition of the oceanographer and the design engineer. The oceanographer must provide a detailed knowledge of scientific principles which govern the behavior of waters in the Gulf of Mexico. He should also have an adequate knowledge of the manner in which design waves are utilized by the engineer. Although the design engineer's primary responsibility is applying the oceanographer's specialized knowledge in the creation of real structures, it is important that he possess some knowledge of related oceanographic principles to reasonably evaluate and apply the recommendations of the oceanographer. In the Gulf of Mexico it is the hurricane wind waves which generally govern the design of an offshore facility. The oceanographer must therefore develop techniques for predicting the heights, periods and frequency of all hurricane waves which might affect a particular structure. From this mass of oceanographic data, the design engineer must select the design waves which will apply to his particular design. PAST STUDIES ON FREQUENCY AND AMPLITUDE OF HURRICANE WIND WAVES Past oceanographic studies on the frequency of hurricane wave heights in the Gulf of Mexico have been devoted largely to predicting the recurrence interval of hurricanes which will generate maximum significant waves of given heights. The maximum significant wave height is the average height of the highest one third of the waves in that portion of the storm producing maximum wave heights. Since these waves occur over a relatively small portion of the storm (Fig. 1) and since the paths of hurricanes vary considerably (Fig. 2), the recurrence frequency of such heights is largely a function of the extent of the geographical area considered. In establishing the frequency of maximum significant waves for the entire American Gulf coast, the major fully developed hurricanes which affected the coastline from BrOwnsville, Tex., to Key West, Fla., were considered (Fig. 2). These Storms were selected and described by C. L-

By Orville R. Lyons

CENTRIFUGAL force has been utilized for the dewatering of fine coal for over 50 years by means of machines commonly called centrifugal dryers. In any centrifuge the coal and water are subjected to a spinning action which usually inctedtocreases in intensity as the coal progresses through the machine. This spinning action, or the centrifugal force that it induces, tears water away from coal particles and produces a dewatered coal. The effectiveness of the dewatering action for any particular machine is governed by the size-consist of the coal and the centrifugal force imparted to the water on the coal. Four makes of centrifuge are currently being used to dewater fine bituminous coal in the United States. These include the vertical, basket-screen C.M.I. (Centrifugal and Mechanical Industries) Carpenter, Reineveld, and the horizontal solid-bowl Bird. The C.M.I. and Reineveld centrifuges are similar in construction and are variations of the Elmore centrifuge, varying principally in the slope of the basket, operating speed, size of perforations in the basket, and diameter of the basket. The same operating description suffices for both. These centrifuges are made up of two rotating elements, an outside conical screen frame and an inside solid cone which carries spiral pusher blades. The screen frame is supported by a hollow shaft, and the solid cone by a spindle shaft passing through the hollow shaft. Both the screen frame and the solid cone rotate at high speeds; the solid cone, with its scraping flights, rotating somewhat more slowly than the screen. The wet coal enters the machine at the top, falls on the cone, and is thrown against the screen by centrifugal force. The coal slides down the screen until it meets the upper end of the flights, where it is moved slowly along the flights until discharged at the bottom. The elfluent passes through the sieve basket or screen and discharges into a launder. The Carpenter centrifuge consists of a conical rotating element with a vertical axis, built up of three rows of perforated stainless-steel plates or stainless-steel wedge-wire or round-wire sections cut and rolled to conform to the surface of the cone. Wet material is delivered to a conical hopper inside the centrifuge casing and is distributed in a thin, even layer over the inner surface of the cone by a disk mounted on the rotor shaft. Impacting of the coal against the screen and the centrifugal force exerted as the material moves downwards creates a dewatering effect. The moisture is forced through the coal bed and then through the perforated plates of the basket, collecting in a circular trough built into the centrifuge. The effluent is conducted from the trough through the centrifuge casing by outlet pipes. The dewatered coal is discharged over the inside bottom edge of the rotor. The Bird centrifuge consists of a tank or truncated conical shell, which is revolved at the desired speed by means of a drive sheave. A screw conveyor rotates inside the cone or bowl at a slightly lower speed in the same direction of rotation. The feed entrance, in the center of the large end of the truncated cone, is high enough to allow formation of a pool of slurry. Adjustable effluent-discharge ports are located in the large end of the bowl so the level of the liquid can be regulated. The solids are moved forward by the screw conveyor as fast as deposited and carried above the level of the pool for an interval before leaving the bowl. In the past these four makes of centrifuge could be compared only by indirect means. The author published a rough comparison method in 1949' but

Jan 1, 1952

By Stephen Zorn

INTRODUCTION The process of financing mining projects in developing countries has changed greatly in the past 15 years. New methods of financing, notably the use of syndicated Eurocurrency project loans, have appeared, and direct equity financing by transnational mining corporations has become less significant. These changes are of particular importance to developing countries which have many mineral deposits still awaiting development, or even discovery. If major new mines are to be financed, host governments will need to obtain more sophisticated information than has hitherto been widely available as to the various sources of finance currently available and as to possibilities for innovative approaches to financing, such as the combination of several different kinds of financing in a single package. This paper reviews the major sources of mining finance potentially available to developing countries and highlights those problems in obtaining adequate financing that developing country producers have begun to experience in the last few years and that are likely to persist through the 1980s. Section I surveys the major types of mining finance; section II reviews specific financing problems, including (a) the withdrawal of the transnational corporations from developing countries, (b) inflation and the size of new projects; (c) developing country indebtedness, and (d) competition among projects in different countries. SOURCES OF DEVELOPING COUNTRY MINING CAPITAL1/ There is a wide range of financing mechanisms which are potentially available to developing countries with economically viable mining projects., Moreover, these financing mechanisms have not been fully exploited by developing countries, and more aggressive pursuit of financing by the governments of these countries may well reveal greater possibilities in respect of any particular project than may initially have appeared. However, virtually all the funds available from these sources are available only to projects which meet the standards of viability acceptable to lenders and others in the business community. If a project does not, for example, promise to generate a discounted cash flow rate of return of at least 15 per cent on total funds employed, or if it does not appear likely to generate sufficient cash flow in the early years of production to cover debt service requirements with a comfortable margin in reserve, most of the sources of financing will not be available. Only where a government has its own financial surplus (as in the case, for example, of the industrialization program of the Saudi Arabian government) can it effectively undertake projects which do not satisfy the definition of economic viability that is accepted at any given time by the worldwide financial community. Internal Sources In Developing Countries Internal financing capacity in developing countries is restricted to a relatively small number of countries - typically those large enough to support a well-rounded industrial sector, in which mining is only one of a number of dynamic industries. While there are large mining companies in certain other countries, the ability of such companies to finance new projects (or even, in some cases, to generate the cash necessary to maintain existing levels of production) is highly problematical. Within developing countries, the possible sources of internally-generated mining finance are the following: (1) state-owned enterprises; (2) private capital; (3) the banking system, and in particular those financing agencies that have a special involvement with the mining sector; and (4) direct budgetary appropriations.

Jan 1, 1985

By F. F. Craig

A series of both welter and gas puttern Hoods was made in the laboratory to study the oil recovery performances of .such operations. These tests were contlrrctt~tl on consolidated sandstone models, using oil. water, and gas. The model floods were scaled to reprotlrrce field performance under gas arid water five-spot injection. X-ray shadowgraphs permitted observation of the gross fluid movement within the models. A method was developed for applying the mobility ratio concept to water flooding and dispersed gas drives in a five-spot well pattern. The area1 sweep efficiency. tit breakthrough for dispersed gas drives is much higher than previorsly expected, Iying in the range of 50 to 100 per cent. A method is presented for predictitig the water-oil ratio performance of five-spot pattern water flood., in uniform sands. This method is verified experimentally for the cotidition of 120 free gas initially present and for va1ues of gas saturation normally encountered in fields following depletion operations. Prodrrction perfort?zut~cc for pattern gas injection is also predictable by this method. INTRODUCTION In field pattern hater flooding or dispersed gas injection operations, the displacing fluid (water or gas) is injected and oil is produced through wells which are, area-wise. small openings in a large container or rescrwir of oil. As a result, not all of the area between the injection and producing wells is necessarily contacted by the injected fluid by the time it first reaches the producing wells. The question arises in predicting oil recovery. as to what traction of the pattern area involved is contacted by either the injected water or gas due to the relative position of the injection and producing wells. This is the areal sweep efficiency. It is also desirable to know how well arrangement affects the oil production performance. A solution to this problem has been attempted by many means. Mathematical analysis¹,²,³, and electrolytic models', have been used to establish a breakthrough areal sweep efficiency of 73 per cent for a five-spot pattern in which the ability of the oil to flow ahead of the invading fluid is equal to the ability of the invading fluid to flow in the invaded zone. All of these studies simulate only one of many field conditions. Improved studies of areal sweep efficiency at breakthrough were made using the fluid mapper5, poten-tiometric models" and X-ray shadowgraph techniques. In these it was possible to study the effect of variations in mobility of the injected and displaced fluids, and so to cover a wide range of field conditions. The limitation of these studies is that, with these models, it was not possible to simulate the saturation gradient behind the flood front when oil is displaced by gas or water. In the most recent published technical paperS on the subject, a method was presented for predicting the oil recovery performance after breakthrough in a five-spot pattern water flood. The method involved correlations which were obtained experimentally using miscible fluids. One limitation of this work was that a saturation gradient, usually found in immiscible fluid displacement, was absent in these studies. Also the laboratory studies did not cover the situation of a water flood following oil recovery by depletion drive. as is the situation in most field water floods. The tests reported in this paper were made using oil. water, and gas, thus eliminating the simplifications of former studies. Also reported are laboratory studies on

Jan 1, 1956

By H. M. St. John

THE melting department is the heart of the foundry. From it clean metal flows to the molding floor, in the right quantity, at the right time and at a sufficiently low cost-or, if not, the foundry fails to thrive. Since it is our purpose here to discuss present-day melting practice in the foundry, it may be well at the start to emphasize the wide differences in foundries and the conditions under which they must operate in order to reach the goal stated in the first paragraph. In every foundry, large or small, jobbing or captive, the same factors must be dealt with but they are of varying consequence and must be dealt with in varying ways in different foundries. Particularly in the nonferrous industry, there is so wide a variation in the composition of alloys used and in the character of castings made that no one type of furnace, nor any one method of operation, can be expected to produce the best results at all times. The present discussion will not attempt to include all nonferrous metals. It is intended to cover only the copper-base alloys in which copper is the dominant element, most of which are commonly known as brass or bronze. The discussion is further limited to the melting of these copper-base alloys for use in sand-casting foundries. Die-casting plants, the brass-rolling mills and certain other metal industries have melting problems peculiar to those industries, which will not be considered here. The following considerations are elemental in all foundries and are listed in what is believed to be the relative order of their present-day importance: I. The melting department must meet the foundry's requirement for dean, fluid metal, of specified composition and purity, at a temperature suitable for the work the foundry has in hand. This is the prime consideration in any foundry, at any time, anywhere. 2. Working conditions surrounding the melting furnaces and attending their use must be good. 3. The cost of molten metal at the mold must be as low as possible. 4. The operating characteristics of the furnaces must be sufficiently flexible, to meet normal variations in foundry requirements. 5. The operation and maintenance of the melting equipment must not require more skill and experience than is available in the particular foundry in question. METAL QUALITY It is not a function of the melting furnace to refine or improve the quality of the metal but simply to melt it without impairing its quality. Good practice requires, therefore, that care must be taken to supply the melting department with metal of inherently good quality, assured by specification or otherwise, having all the properties necessary to produce the castings desired. An alloy contains a number of primary elements, which must be present in definite proportions if the castings made from it are to have the desired properties. If the castings are made to a customer's specification, this will state the range within which these principal elements (for example, copper, tin, lead and zinc) are permitted to vary.

Jan 1, 1946

By John Griffen

The modern anthracite breaker or washery uses almost exclusively a wet method of preparation, which requires, roughly, 1 gal. of water per minute per ton of production per day. The entire anthracite industry uses about 320,000 gal. per min. of water for this purpose or 800,000 tons of water per day. As this water leaves the breakers, it contains fine solids—coal, slate, pyrite, and clay—and is then called silt or slush; as slush is the term most commonly used, it will be employed throughout this paper. The solid content of the slush will be referred to as solids. In the earlier days of anthracite mining, little coal was washed, less crushing was employed, and virgin coal was mined exclusively. As a result, the slush problem was not acute because of the relatively small quantity and the coarseness of the solids. Such slush as was produced could usually be easily impounded and retained or could be discharged into streams without any appreciable pollution being apparent. The character of the fine waste from the breakers changed materially as its quantity increased until now about 40,000 tons of slush solids are produced daily. Second mining and robbing operations materially increased the quantity of fine solids delivered to the breaker in the mine car. The demand for chestnut, stove and egg sizes, to the exclusion of grate, steamboat, and lump sizes, requires finer crushing of the mine-run coal with a consequent increase of fine solids in slush. The use of rice and barley sizes removed a considerable tonnage of coarser solids from the slush but left great quantities of fine solids difficult to retain completely, and to store, and long considered of no possible fuel value. Despite the efforts of the coal operators, the slush solids have found their way into the streams causing, in some cases, serious pollution. The Water Supply Commission of Pennsylvania published, in 1916, a report on Culm in the Streams of the Anthracite Region,' from which the following is taken: About 40,000,000,000 gal. of water carrying 10,000,000 tons of fine culm are discharged into the water-courses direct, flushed into the mines, or disposed of by various means on the surface. The extent to which the very small sizes of anthracite have been deposited in the rivers draining the coal fields is made evident by the fact that over a quarter of a million tons are recovered annually from the river beds by coal-washing operations.

Jan 1, 1922

By Takahide Wakamatsu, Yoshiaki Numata, Charn Hoon Park

INTRODUCTION A technique is needed to apply the flotation method successfully to apply the flotation method successfully to low grade and complex ore bearing hard-to-float oxide minerals. Thus it is necessary to find a new selective, powerful collector or to develop a new flotation process. Some attempts to use two or more kinds of collectors combined in flotation have been made but the principle of the reaction between the collectors used and the surface of mineral as well as the effect of combined collectors on flotation has not yet been fully understood. As part of the study on the improvement of selective collection in flotation, we have been investigating the flotation of minerals using two kinds of organic reagents, one of which is a conventional collector. We found xanthates were able to adsorb even onto the surface of oxide mineral, with the help of another organic reagent, e.g. a chelate compound (1). Furthermore, a notable effect of combined reagents such as the xanthate-amino acid combination (2) was found on the reagent adsorption phenomena and the collection phenomena, depending on the combination of reagents. The present study was carried out to clarify the effects of adding two kinds of collectors to the collection of mineral in flotation in the following two cases: (1) joint use of xanthate and di-alkyl dithiophosphate for galena collection and (2) joint use of a cationic collector with xanthate for scheelite collection.

Jan 1, 1980

By Linda P. Bono

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

Jan 9, 1978

By Douglass D. Donald

The New Jersey Zinc Co. successfully holed through a 2 ½ -mile haulage tunnel connecting its new Ivanhoe shaft with the Van Mater Shaft at Austinville, Va. This 8 x 10-ft cross-section tunnel was driven from both ends and met at a point approximately a mile from one shaft and a mile and a half from the other. In order to make certain that the faces met accurately on line and grade it was necessary to refine conventional mine surveying practices. The mines that are serviced by these shafts are located in the southwestern part of Virginia approximately midway between Roanoke and Bristol at the west foot of the Blue Ridge. While the presence of lead-zinc sulfide ores has been known in this area for more than 200 years, it was in 1902 that New Jersey Zinc Co. acquired the Austinville property, which has been in constant operation since that time. About ten years ago the company undertook an extensive diamond drilling program at Ivanhoe several miles to the southwest. This program was successful in locating sufficient ore to justify the purchase of a number of the properties in this area and plans were made to develop the new orebodies. The discovery of this ore as well as substantial additional reserves at Austinville resulted in a decision by the company to increase its daily milling capacity to 3000 tons, of which about 1000 tons would be supplied from the Ivanhoe mine.

Jan 9, 1958

By Allan T. Fisk, Carl R. Peterson, Richard E. Brooks, James J. Olson

Development of a continuous drill-and-blast excavation capability in mining and high-speed tunneling has been a long recognized goal. Ideally, a machine to meet the challenge should simultaneously perform drilling, explosive loading, initiation, mucking, ventilation, and other functions while remaining at the face, since the elimination or modification of the cyclic nature of the system would significantly improve the advance rate and economy of drill-and-blast tunneling. The Rapidex continuous spiral drill-and-blast concept, one of the continuous excavation schemes presently under evaluation in the US Bureau of Mines' Bedded Deposits subprogram, utilizes an unusual blasting pattern that provides effective fragmentation and involves a partially self-shielding geometry that permits a lightly shielded machine to remain at the face during blasting.

Jan 6, 1977

By J. E. Walstrom

While intensive research continues to promote a more complete understanding of the potential and resistivity measurements that comprise the electric log, it is believed that consideration should also be given to translating these numerous and often widely separated findings into a coordinated and readable body of fundamental facts designed specifically for the petroleum engineer and geologist. Although provision is made through publication for a ready exchange of new theoretical concepts. it is also desirable to provide reviews and appraisals of the more established techniques and methods from the operating standpoint so that an economic and practical application may be realized concurrently with the theoretical progress. With these basic premises as a guide the author reviews the presnt state of electric log interpretation. The paper is directed not so much to the logging or research specialist as to the petroleum engineer and geologist to whom the electric log is only one of the many tools which he employs. Frequently, these persons do not have the time to follow in detail the many specialized contributions that appear and, as a consequence. are not in a position to place these contributions in proper relation to each other, or to the art as a whole. The paper reviews the basic steps in making quantitative determinations from the electric log of the amount of oil or gas present in subsurface formations and also discusses the degree of reliability of these determinations under various conditions. The paper also indicates the trend of future developments in electric logging systems and methods of interpretation. INTRODUCTION The electric log has been used about 20 years as a means for studying the formations penetrated by a well bore. The first half of this period is characterized by the development of suitable logging techniques and equipment. Although progress in this direction is continuing at a satisfactory rate, the last ten years are characterized more by an increasing interest in methods of electric log interpretation. During this period, a large number of fundamental papers have been published, expounding various logging techniques and particular phases of the interpretation problem. Many of these papers represent important contributions, and a few are classic. This paper is an effort to outline as concisely as possible and in simple terms the main course of progress in electric log interpretation. More specifically, it is the purpose of the paper to review the necessary elements and basic steps used in making quantitative determinations of water saturation from the electric log; and to point out the degree of reliability of these determinations under different conditions. It is strongly advised that the operating staffs of the drilling and exploration departments of oil companies cooperate wholeheartedly with both the electric logging service companies and research organizations in the testing and development of new logging systems and interpretation methods. One purpose of the paper is. however, to indicate the degree of caution which must be exercised in placing confidence in new techniques and interpretation methods that have not been thoroughly tested in the field. It is entirely possible to be cooperative in trying new methods and yet reluctant to believe in the results until the methods are firmly established. It is important to define the meaning of quantitative electric log interpretation. In the most general sense, an interpretation of the log has been made when the electrical characteristics of the formations, as portrayed on the log, have been translated into terms describing the formation geometry, rock type, or any other physical characteristics of the formations. The determination that the top of a sand is at a certain depth is an interpretation of the log. Structural determinations made by correlating electric logs from a given area are also interpretations of the logs. The term quantitative interpretation, however, will be used in this paper in the restricted sense to indicate the determination of the water saturation of a formation. This determination defines the fluid content of an oil and gas productive formation only if the porosity is known, and it assumes that the remainder of the pore space contains hydrocarbons. This assumption is believed to be true for most oil and gas productive formations. The quantitative electric log interpretation may he said to be a determination of the fluid content only to the extent which the water saturation, under the conditions given above. defines it. THE BASIC STEPS The fundamental steps in calculating water saturation from the electric log are: 1. Determination of the true resistivity of the formations from the apparent resistivities as recorded on the electric log.

Jan 1, 1952

By J. E. Ryan

TRONA, Calif., is a miniature urban community of some 3500 people, located on the northwest shore of dry Searles Lake in the extreme northwest corner of San Bernardino County, approximately 186 miles north and east of Los Angeles. Since it is situated on the Mojave Desert, a typically desert climate prevails with wide variations in temperature between day and night, extreme daytime summer heat, and cool to cold winters. Rainfall averages somewhat less than 4 in. per year, and dust storms are common. The rate of evaporation, .however, is great, amounting to 6 to 9 ft of water per year. The extremely low humidity makes the summer heat of 110°F tolerable with only a mild, temporary discomfort. Nature of Deposit During the periods when Searles Basin was flooded, the waters that passed through Indian Wells Valley spread out to form a broad, shallow lake providing, in effect, a settling basin for suspended sediment. The drainage into the deeper and more isolated Searles Basin thus was clarified to a great degree before concentration began. Today, the elevation of the dry surface of Searles Lake is 1618 ft, and the salt deposit measures 5x7 miles. At the eastern and northeastern margins of the main playa zone and just at the foot of the alluvial slope of sand and coarser wash from the Slate Range mountains, a rim of crusted salts rises a few feet above the level of the flat. The deposit is a saline efflorescence composed of salts that were presumably brought up with rising ground waters to be deposited at the surface by solar evaporation. This deposit consists chiefly of trona, and it is after this Trona Reef that the town Trona was named. Strip mining operations have been conducted in the past at infrequent intervals for the recovery of crude trona salts. The main focal point of interest in Searles Lake from a commercial standpoint is the main salt body located almost centrally in the basin. The exposed portion of this porous saline deposit covers approximately 12 sq miles and averages 71 ft deep. Its interstitial voids, which constitute 50 pct of the total volume, are permeated with a brine, which is in equilibrium with the soluble salt deposits. The brine is the raw material for the operations of the American Potash and Chemical Corp. plant at Trona, shown in Fig. 1. The soluble salt deposits are of interest for their potential values in future technologic development. The brine, which is stratified according to slight differences in density, stands usually within 6 in. of the surface of this exposed, firm, salt body. The surface is usually dry and will support the weight of heavy mobile units and drilling equipment. Occasionally, however, surface waters from the higher watersheds encroach upon the main salt body during infrequent periods of precipitation on the surrounding mountains. This water dissolves surface salt, becomes a dilute brine, and has been observed to stand as high as 18 in. above the salt surface when undisturbed. Windstorms will shift the water back and forth across the lake surface. The exposed salt body is surrounded by additional submerged areas of commercial soluble salt deposits covering some 20 sq miles, hidden from view by marginal playa mud. These vary in depth up to as much as 30 ft. Thus, the outline of exposed and submerged salt deposits of commercial value is estimated to cover a total area of 32 sq miles, which is roughly circular but slightly elongated from northwest to southeast. It has been estimated that each square mile contains about 100 million tons% f alkali salts. The results of drill borings in the past 15 years have brought to light the interesting fact that the main salt body lies superimposed on an impervious mud deposit from 10 to 15 ft thick containing relatively little soluble salt. Under this deposit lies a second soluble salt body 35 ft deep. The lower salt body is interspersed with numerous insoluble mud lenses and its composition is considerably different from that of the primary, or main salt deposit. Recent drill borings have not penetrated beyond 300 ft. They have, however, revealed that underlying the lower salt body, the mud sediments carry deposited minerals of trona, nahcolite, mirabilite and much less soluble carbonates or sulphates of calcium and/ or magnesium. This structure is shown in Fig. 2. Current Lake Survey Program Several hundred holes have been drilled in the deposit. However, to carry out a thorough and carefully correlated study of the composition of the soluble salts and other minerals in the dry lake basin, a drilling program was inaugurated recently and is now nearing completion. In this survey, pattern drill holes are sunk at regular lh-mile intervals to a depth of approximately 150 ft. Drilling equipment consists of a No. 51 C. P.

Jan 1, 1952

By P. Chiotti, G. R. Kilp

Thermal, metallographic, vapor pressure, and X-ray data were obtained to establish the phase diagram for the zinc-zzrconiz~m system. Five compounds corresponding to the stoi-chiometric formulas ZrZn, ZrZn,, ZrZn,, ZrZn,, and ZrZn14 were observed. All these compounds, with the exception of ZrZn2, which melts congruently at 1180°C under constrained zinc-vapor conditions, undergo pexitectic reactians. The temperature at which the zinc vapor pressure is I atm for a series of alloys was determined from vapor-pressure measurements. The data obtained are summarized in the construction of a I-atm-pressure phase diagram and a phase diagram corresponding to a pressure of less than 10 atm. THE purpose of this investigation was to establish the phase diagram for the zinc-zirconium system. Thermal, metallographic, vapor pressure, and X-ray data were employed in determining the phase regions. Partial investigations of this system have been conducted by Gebhardt1 and Carlson and Borders.' Carlson and Borders studied the high-zirconium region and established the existence of a eutectic at 69 wt pct Zr with a melting point of 1015°C. The terminal phases of the eutectic horizontal were shown to be an intermetallic compound ZrZn and a solid solution of ß zirconium containing 21 wt pct Zn. The ß solid solution decomposes into ZrZn and a zirconium at 750°C. The eutectoid composition is given as 15 wt pct Zn, and the solubility of zinc in a zirconium at temperatures below 750°C is indicated to be negligible. Gebhardt studied the zinc-rich region and observed a lowering of the melting point of zinc from 419.5" to 416°C and temperature horizontals at 545" and970°C. Some preliminary observations by Chiotti, Ratliff, and Kilp were reported by Hayes.2 pietrokowsky3 has reported the compound ZrZn2 to have a cubic MgCu2 structure with ao = 7.396A. MATERIALS AND EXPERIMENTAL PROCEDURES The metals employed in the preparation of alloys were Bunker Hill slab zinc or Baker analyzed reagent granulated zinc, both 99.99 pct pure and hafnium-free iodide-process crystal bar zirconium obtained from the Westinghouse Electric Corp. The zirconium contained 200 ppm Fe, 200 ppm Si, 100 ppm C, and minor amounts of other impurities. The zirconium was milled or machined into thin chips or shavings. These were cleaned with a nitric-hydrofluoric acid solution, rinsed with water, and acetone, and dried just prior to their use in alloy preparation. The granulated zinc was similarly cleaned using dilute nitric or hydrochloric acid. Weighed quantities of these materials, 20 to 30 g total, were mixed and pressed at 20,000 to 70,000 psi to give relatively dense compacts. During the early part of this investigation the pressed compacts were placed in MgO-15 wt pct MgF, crucibles which were then sealed inside of quartz ampules. The compacts were given various prolonged heat treatments prior to their use for thermal analyses, or vapor-pressure measurements. Because of expansion of the compacts and the relatively high zinc vapor pressure it was difficult to heat to the melting temperatures of the alloys without failure of the quartz ampules. Homogenization at temperatures below the melting temperature gave brittle, porous alloys unsuitable for metallographic examination. It was also difficult to prevent condensation and segregation of zinc on the colder parts of the quartz ampules during heating and cooling operations. These problems were eliminated to a great extent by the use of tantalum crucibles. Tantalum proved to be a satisfactory container with little or no reaction between the alloys and the tantalum. Small tantalum thermocouple wells were successfully welded in the bottom of these crucibles. Pressed compacts were sealed inside the tantalum crucibles by welding on preformed caps under an argon atmosphere. Heat treating and differential thermal analysis were combined into a single operation. The experimental sample assembly is shown in Fig. 1. This assembly was enclosed inside a stainless-steel tube heating chamber which could be evacuated and filled with an inert gas. The thermocouple leads were brought out of the heating chamber between two rubber gaskets used to provide a vacuum seal for the water-cooled head. Most of the compounds in this system undergo peritectic decomposition. After heating above the temperature of a particular peritectic horizontal the sample was cooled to just below the peritectic temperature and held at temperature for several hours. The sample was then reheated through the peritectic temperature and the size of the thermal arrest, if still present, compared with the one previously obtained. If the thermal arrest was not characteristic for the alloy composition being investigated its magnitude diminished and repeated cycling and annealing eventually eliminated it. The peritectic thermal arrests characteristic of a particular composition were established in this manner.

Jan 1, 1960

By Thomas A. Simpson, Russell A. Walker

Hydrogeological techniques were used to solve problems of slope stability in open-pit mines of the Eufaula bauxite district, Ala. Geologic and hydrologic data were evaluated and used to design a system of dewatering wells to enable the operators to mine bauxite more efficiently and economically. Walls of open-pit mines in the district were subsequently stabilized by the operation of the dewatering system. Three open- pit mines, each at varying stages of the mining process, of the A.P. Green Refractories Co., were used to develop a sequential series of guidelines that indicate how to effectively remove ground water from the formations surrounding the ore bodies in the district. The use of sound engineering principles in well design, in combination with the correct interpretation of the pit hydrology provided the basis for solutions of the slope-stabilization problem and aided in the economical removal of bauxite from mines of the district.

Jan 1, 1976

By W. C. Schroeder

PRACTICAL experience has shown that at elevated temperatures solu-tions containing sodium hydroxide may attack stressed steel in a manner that cannot be explained in terms of ordinary corrosion. Because the ductility of the metal has been greatly reduced during the reaction, the entire phenomenon is usually called "embrittlement." Thus, after several years of operation caustic evaporators have been so badly embrittled that rivets could be cracked off with the blow of a hammer. Since fine intergranular cracks are almost always present in the zone of fracture, it has often been assumed that a process of selective corrosion in grain boundaries was responsible for the failure, although this has not been clearly proved experimentally. Concentrations of sodium hydroxide below those necessary for the uniform, rapid attack of the steel surface are reported to be most effective in producing embrittlement2,3. In the operation of steam boilers a similar type of failure has been found, mainly in riveted seams or other capillary spaces where the solu-tion may concentrate and where high stresses may also exist. It is believed that in such localized areas the dissolved solids may reach a value many times the few hundred parts per million prevalent in the body of the boiler. While this type of boiler failure has been the subject of investigation for a period of 20 years', an understanding of its mecha-

Jan 1, 1936

By H. H. Waller, C. H. Brehaut

At the Jeffrey mine of Canadian Johns-Manville Co. in Asbestos, Que., automatic batched concrete from surface is placed underground pneumatically for distances of 2500 ft directly into forms or to a second placer for greater distances, through 6-in. pipe of high carbon steel. The use of Celite C-4-C in addition to the usual aggregates achieves greater compressive strengths, lowers cost, reduces segregation, and improves workability and placeability results. Each year 25,000 cu yd of concrete are placed without interrupting production and development work in the mine, making possible a cheaper concrete that can be poured wherever and whenever it is needed. In about 90 pct of the underground openings in the Jeffrey mine concrete is necessary to preserve them in their original sizes and shapes for production. In the remaining 5 pct, the greater portion is united with or without steel support. When large quantities of concrete were forecast for underground use at the Jeffrey mine, preliminary and first hand information regarding pneumatic placing was acquired from articles by Bernhardt and Swanson and visits to their respective mines.

Apr 1, 1956

By E. D. Hummer, J. A. Younkins. J. P. Proctor

Comparatively little has been published relating practical experience with the control of the solid content of washery water systems that must be "closed." A "closed" system is one that for some reason may not be cleaned by the emission Of any effluent Of high ''lid 'content to be rep1aced by 'lean water in Order to hold the solid content of the waste water within reasonable bounds for efficient washing. It is the Purpose of this Paper to describe practical experience with such a water system and to present data that it is hoped may be of some use to those who are faced with a similar problem. The washery clarification system described comprises three thickeners and three filters, and although it is admitted that each of the fields of water settling and thickening and filtration offers a wide scope for investigation, the authors are not attempting to present the answers to these problems but to set down the results of some experience along these lines, making no claims as to the ultimate solution of the problems in hand. The subject of water clarification has vast ramifications; for example, the science of flocculation as applied to water settlillg and filtering opens up fields of wide possibilities of which as yet little is known. A comparatively recent entry into the field of water treatment, which may offer possibilities of practical application, is the use of "wetting" agents such as "Aerosol." General Arrangement of Water System So that the reader may obtain a comprehensive picture of the factors concerned in the control of a closed water system, it is necessary to give a brief description of the washing plant that is serviced by the water system to be described in the following pages. As we are not primarily concerned with the washing plant in detail, only a brief description of the flow of coal as it relates to the water system will be given here. For a more detailed account of this type of washer, the reader is referred to earlier papers,1,2 The washer, which handles o to 4-in, raw coal (750 tons per hour) is an American Rheolaveur plant of two complements; the coarse coal or sealed discharge plant and the fine coal or free discharge plant. The sealed discharge plant (Fig. I) consists of twin 48.in. primary launders, each having two washing boxes, supplemented by one 32-in. rewash launder, which also has two washing boxes. "Push" water for washing and conveying coal in these launders is supplied from a constant-head tank under pressure head of 10½ ft. at the point of introduction at the feed end of the launder. This tank also supplies water for upward or vertical currents used in the Rheolaveur or washing boxes. Each box discharges into a sealed boot elevator (Fig. I).

Jan 1, 1942