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By John Birkinbine

An item of considerable importance to the producers of pig-iron is the disposition of the slag or cinder from the blast-furnace; and various plans have been adopted at different works to care for the rapid accumulation of this generally waste material. The charge per ton of iron made which must be allowed for the care of cinder is sufficient in times of business depression to give plants having facilities for disposing of their slags an advantage over others less favorably arranged, and to allow iron to be produced profitably in the one case and prevent a profit in the other. The varied methods employed and the means of conveyance utilized need not be detailed. It is sufficient to say that the large outputs of American blast-furnaces, and consequent rapidly augmenting dump-piles, have brought into general favor the use of cars carrying the slag in a liquid condition. The advantages of this method are the prompt removal of the slag, the reduced space occupied by the dump-piles, and the facility of converting the slag into such forms for use as may be desired. The progress in iron-manufactlire is also marked by a more general adoption of methods by which molten metal is carried in vessels away from the point of its production; and, anticipating the prospective advance in pig-iron manufacture, it does not seem unreasonable to prophesy the early abolition of casting-houses at blastfurnaces, particularly where several are grouped together; or the casting of steel ingots away from the converters or furnaces. In some large blast-furnace plants, the iron is carried molten from the blast-furnaces to the converters or other furnaces. Even where it is cast into pigs, casting-sheds removed from the immediate vicinity of the furnace-stack would, perhaps, be superior to casting in beds in front of the furnaces. The idea of casting-sheds appears to present the following advantages : 1st. The equipment of boilers, hot-ovens, and blowing-machinery could be closely grouped around the blast-furnace stacks, permitting

Jan 1, 1887

By Charles Will Wright

ITALY is by- far the poorest in mineral resources of the so-called great pou7ers of Europe. Before the World War this shortage was not so serious as the essential minerals that could not be mined domestically at a profit were bought in the world markets. In those days tourist trade and remittances from Italians abroad helped to provide Italy with foreign exchange. During the World War, when certain mineral products were scarce and when prices rose in some instances to several times normal, the Italian Government began to regulate consumption and imports. It was not until later, when the Fascist regime established the corporate state, that Italy seriously considered adopting a of self-sufficiency. Private industry was grouped under separate corporations, for the principal industries; including mining and metallurgy and the heads of the large producing companies, became members of these corporations. Industrialists were thus able to regulate their own affairs and to advise the Government as to the measures necessary to meet domestic or foreign trade demands upon their industry. Labor was or-

Jan 1, 1939

By K. J. Kutz, F. A. Nice

Drilling of the second shaft at Texas Gulf Sulphur Co.'s Cane Creek potash operation southwest of Moab, Utah, is perhaps the largest undertaking ever made by private industry in the field of rotary shaft drilling. The new shaft, known as No. 2, is located within the plant area, about 400 ft northeast of the No. 1 shaft. This location within the pillar of the first shaft allowed utilization of a great deal of in- formation gained prior to and during sinking of the original No. 1 shaft, a conventionally sunk 22-ft diam shaft 2789 ft deep. The No. 2 shaft will be used for auxiliary transportation of men and supplies, and is steel lined with a 48-in. ID casing. The top 825 ft of the shaft is in predominantly red sandstone with interbedded shales. From 825 ft to 2800 ft, which is the top of the salt beds, the rock is mostly limestone with interbeds of anhydrite and shale.

Jan 9, 1968

By Samuel Doak

THE utilization of rotary kilns, of the well-known cement type, for the preparation of iron ores, for the blast furnace, has become of considerable economic importance within the past 10 years in certain localities, notably those where the native ores are lean. Such kilns may be used simply for the agglomeration of ores too fine to be charged into the blast furnace (i.e., ores whose loss in the dust catchers is excessive, and whose fineness is detrimental to the working of the furnace), or for the desulphurization of lump and fine ores the sulphur content of which does not exceed 6 or 7 per cent. The desulphurizing action can be combined with that of agglomeration provided the kiln is sufficiently large. Other processes have been developed for the same purpose, but while I am not able to draw a comparison between them by reason of lack of sufficient data, it is safe to say that the kiln, if properly dimensioned for the character of ore to be treated, will compare favorably in its results, both as to economy and quality of product, with any other process. It is not, however, as well adapted for the treatment of flue dust, as is a sintering operation, on account of the large percentage of fine coke contained therein. Any combustible entering the kiln at its feed end renders the process very much more expensive and unsatisfactory on account of the difficulty of controlling the temperature, also because of the rapidity with which long "rings" form, due to the increased heat at the cooler end of the kiln. The greatest value of the kiln at present is in the treatment of pyrites cinder; that is, the residue from pyrites ore after the extraction of the greater part of the sulphur. This cinder, while high in iron content, has too much sulphur remaining in it to be allowed to form a large part of the blast-furnace burden, without further treatment. It will range in metallic iron from 42 per cent., representing a very low-grade cinder, from a domestic pyrites, to 64 per cent. of the residue from the best Spanish ore, and the corresponding silica content will vary from the maximum of about 25 per cent. to 1 ½ per cent. The residual sulphur depends largely on the type of burner used in the original desulphurization. In general, the leanest original ores retain the greatest amounts of sulphur. In

Jan 9, 1915

By J. E. Norton

PRODUCTION statistics show that during the period of emergence from the depres¬sion the coal industry was becoming increasingly cognizant of the economic and competitive necessity for mechanizing. About 1935 many of its leaders were becoming aware also of the alarming scarcity of men properly trained to cope with the new problems of mechanization. In order to get a factual statement of this problem, a special AIME Coal Division Committee + was requested to survey the condition. Its investigation disclosed that graduates of mining schools going into coal mining numbered 16 in 1939 and 15 in 1938. With this as a background, Pittsburgh Coal Co. foresaw that a comprehensive program was necessary if it was to enlist the services of trained technical men, who were an indispensable part of a mechaniza¬tion program. The purpose of this paper is to review the program set up, to comment on the successes and failures and to outline the future course of action. SUMMER WORK An inescapable conclusion from the mechanization statistics was that the opportunities in coal mining were good. Not only was there a void in technical skill to fill from past years, but the ac¬celerating rate of mechanization indicated an increasing demand for technically trained men for the future. The remedy lay primarily in presenting facts con¬cerning the coal industry to the under¬graduate engineers before they made their professional occupational choice. Based on this idea, one of the key points in the program - was summer vacation work for the undergraduate, which, through the inducement of summer earnings, brought men into the mines to take a look at the prospects. This was more successful than statistics indicate because the war badly scrambled the orderly working of the program, but it could not obscure the value of a summer work program. A decided advantage was that it gave the company a preview of the graduate. An observation on this part of the program is that it is extremely hard to gauge lower classmen, and we found it wise to give them the benefit of the doubt, as the last two years in college bring about surprisingly rapid develop¬ment in some men. We could readily single out the men at the opposite ends of the scale of competence. COMPREHENSIVE TRAINING PROGRAM Having adopted summer work as a

Jan 1, 1946

By John Lamont, Walter Crafts

The principle formulated by Grossmannl for calculating hardenability of steel by multiplying the ideal diameter of "pure" iron-carbon alloys by factors for grain size and alloying elements has been confirmed on many steels and has proved useful in designing substitute alloy steels. Grossmann found that the typical behavior of the multiplying factors was to increase directly in proportion to the amount of the alloy present in a steel. However, the multiplying factor for the effect of silicon on hardenability was found by Grossmann to increase to a lesser degree as the amount of silicon was increased. In view of the increasing use of silicon in heat-treating steels, the effect of silicon on hardenability is becoming more important. Calculation of the hardenability of high-silicon steels made at the Union Carbide and Carbon Research Laboratories, Inc., indicated that the multiplying factor for silicon increased directly in proportion to the amount of silicon present. A more extended study of high-silicon steels covering fairly wide ranges of grain size, carbon, manganese, and aluminum has confirmed that up to 2 per cent silicon the multiplying factor is directly proportional to the silicon content. Manganese and aluminum factors have also been! determined. The results of the study offer strong confirmation of the general validity of Grossmann's multiplying principle. Testing Procedure Steels on which the study of the effect of silicon on hardenability was based were made in high-frequency induction furnaces using Armco iron and standard alloying materials. The ingots were forged to bars, and sections were normalized prior to machining Jominy hardenability test specimens. The Jominy test was carried out under standard conditions.2 The depth of hardness penetration for determination of ideal diameter at "half hardness" was taken at the hardness level indicated in Fig. 29 in Grossmann's paper by the solid line for 50 per cent martensite in plain carbon steel. The depth of penetration of hardness on the Jominy specimen was converted to ideal diameter by the relation given in Fig. 28 of Grossmann's paper. Chemical analysis was determined on a sample taken adjacent to the Jominy specimen. Aluminum was determined as "acid-soluble aluminum" rather than as total aluminum, as it is probably more representative of the aluminum that is effective as an alloying agent. In addition to the elements nominally present in the steels, analyses were made for residual phosphorus, sulphur, nickel, copper, molybdenum and chromium on one heat of those made with the same materials during the same period. Actual grain size was determined by microscopic examination of small samples quenched in water after receiving the same thermal cycle as the Jominy hardenability specimens. Chemical analyses, heat-treatment, grain size, and hardenability are shown in Table I representing three ranges of composition.

Jan 1, 1943

By John Lamont, Walter Crafts

The principle formulated by Grossmannl for calculating hardenability of steel by multiplying the ideal diameter of "pure" iron-carbon alloys by factors for grain size and alloying elements has been confirmed on many steels and has proved useful in designing substitute alloy steels. Grossmann found that the typical behavior of the multiplying factors was to increase directly in proportion to the amount of the alloy present in a steel. However, the multiplying factor for the effect of silicon on hardenability was found by Grossmann to increase to a lesser degree as the amount of silicon was increased. In view of the increasing use of silicon in heat-treating steels, the effect of silicon on hardenability is becoming more important. Calculation of the hardenability of high-silicon steels made at the Union Carbide and Carbon Research Laboratories, Inc., indicated that the multiplying factor for silicon increased directly in proportion to the amount of silicon present. A more extended study of high-silicon steels covering fairly wide ranges of grain size, carbon, manganese, and aluminum has confirmed that up to 2 per cent silicon the multiplying factor is directly proportional to the silicon content. Manganese and aluminum factors have also been! determined. The results of the study offer strong confirmation of the general validity of Grossmann's multiplying principle. Testing Procedure Steels on which the study of the effect of silicon on hardenability was based were made in high-frequency induction furnaces using Armco iron and standard alloying materials. The ingots were forged to bars, and sections were normalized prior to machining Jominy hardenability test specimens. The Jominy test was carried out under standard conditions.2 The depth of hardness penetration for determination of ideal diameter at "half hardness" was taken at the hardness level indicated in Fig. 29 in Grossmann's paper by the solid line for 50 per cent martensite in plain carbon steel. The depth of penetration of hardness on the Jominy specimen was converted to ideal diameter by the relation given in Fig. 28 of Grossmann's paper. Chemical analysis was determined on a sample taken adjacent to the Jominy specimen. Aluminum was determined as "acid-soluble aluminum" rather than as total aluminum, as it is probably more representative of the aluminum that is effective as an alloying agent. In addition to the elements nominally present in the steels, analyses were made for residual phosphorus, sulphur, nickel, copper, molybdenum and chromium on one heat of those made with the same materials during the same period. Actual grain size was determined by microscopic examination of small samples quenched in water after receiving the same thermal cycle as the Jominy hardenability specimens. Chemical analyses, heat-treatment, grain size, and hardenability are shown in Table I representing three ranges of composition.

Jan 1, 1943

By Augustus Locke

Two Opposed Interpretations of the Tonopuh Structure.—The important geological publications concerning the Tonopah min-ing-district are those of Spurrl aud of Burgess.² In these publications are presented fundamental differences of interpretation, which are the more interesting because both authorities have had ample opportunity for observation, and because both are geologists of proved ability. I was vastly puzzled to know which had the better of it, and in order that I might reach a conclusion in my own mind, I recently spent some time in the district going over the physical evidence. Surprising as it may seem, this evidence looks conclusive. A review of it will, I believe, be of interest to those who are familiar with the previous publications. The general geological features of Tonopah are shown in Fig. 1, and the differences of interpretation referred to are outlined in the accompanying notes. Brieflyj Burgees regards the various rocks as flows, lying in the order of their deposition. Spurr regards them in part as flows, and in part as flat-lying intrusives. The disagreement, then, concerns the rocks regarded on the one hand as intrusives, and, on the other hand, as flows. These rocks are chiefly the so-called calcitic andesitc, the upper rhyolite, and the lower rhyolite. Economic Importance of the Question of Interpretation.—The economic importance of the question of interpretation is, of course, limited to its bearing on the probable distribution of

Jan 1, 1913

By William E. Schoeneck

This paper presents the problem of oil-well abandonment as a group of studies involving the compilation of physical well data, the use of special curves, maps, and interpretative Procedures, in order that operations can be analyzed and means for reducing costs can be effected. Methods for the calculation of the economic limit of production and resultant oil reserves are suggested in order that profitable production may be continued and premature abandonment prevented. INTRODUCTION Purpose Extensive studies have been made and much has been written on the procedures for prospecting, drilling, completion, production and repair of oil wells, but the writer has long felt the need for a study of the procedure that should be followed when considering the abandonment of a well. The production from numerous well bores of a fluid material (a circumstance peculiar to the oil industry) that is continually decreasing in quantity leads to an increasing ratio of operating cost to production. It is for this reason that oil fields are not abandoned as a whole and detailed consideration of each well is required before it can be determined whether more is being expended than will be returned On any well or lease in question. It is the purpose of this paper, therefore, to compile, correlate, and present all matters worthy of consideration in the problem of oil-well abandonment; to suggest interpretative procedures based on such compilations, to the end that reliable estimates of reserves and life may be obtained; to show, as a result of such interpretative procedures, the possibilities for corrective measures conducive to economical production, thereby extending both profitable reserves and length of life. Scope and Approach Compiling data and outlining a study having the complexity of the problem at hand are naturally subject to the personal experiences of one who undertakes the study; however, the chosen approach and grouping of the subject material may be helpful in the consideration of abandonment problems. Consideration has been given to wells that make gas and water incident with the production of oil; but consideration has not been given to either gas wells or condensate-producing wells, for wells of the latter type have sufficient problems to warrant separate investigation. The major subdivisions of this paper-— physical considerations and economic considerations—do not imply that either of these phases can be considered independently, but rather that the two are mutually dependent and are the component parts of an engineering study.

Jan 1, 1946

By William E. Schoeneck

This paper presents the problem of oil-well abandonment as a group of studies involving the compilation of physical well data, the use of special curves, maps, and interpretative Procedures, in order that operations can be analyzed and means for reducing costs can be effected. Methods for the calculation of the economic limit of production and resultant oil reserves are suggested in order that profitable production may be continued and premature abandonment prevented. INTRODUCTION Purpose Extensive studies have been made and much has been written on the procedures for prospecting, drilling, completion, production and repair of oil wells, but the writer has long felt the need for a study of the procedure that should be followed when considering the abandonment of a well. The production from numerous well bores of a fluid material (a circumstance peculiar to the oil industry) that is continually decreasing in quantity leads to an increasing ratio of operating cost to production. It is for this reason that oil fields are not abandoned as a whole and detailed consideration of each well is required before it can be determined whether more is being expended than will be returned On any well or lease in question. It is the purpose of this paper, therefore, to compile, correlate, and present all matters worthy of consideration in the problem of oil-well abandonment; to suggest interpretative procedures based on such compilations, to the end that reliable estimates of reserves and life may be obtained; to show, as a result of such interpretative procedures, the possibilities for corrective measures conducive to economical production, thereby extending both profitable reserves and length of life. Scope and Approach Compiling data and outlining a study having the complexity of the problem at hand are naturally subject to the personal experiences of one who undertakes the study; however, the chosen approach and grouping of the subject material may be helpful in the consideration of abandonment problems. Consideration has been given to wells that make gas and water incident with the production of oil; but consideration has not been given to either gas wells or condensate-producing wells, for wells of the latter type have sufficient problems to warrant separate investigation. The major subdivisions of this paper-— physical considerations and economic considerations—do not imply that either of these phases can be considered independently, but rather that the two are mutually dependent and are the component parts of an engineering study.

Jan 1, 1946

[ ] Granville S. Borden (Mining Taxation, P. 1049) has written two other published articles on the subject, Taxation and Mineral Resources, and An Income Tax Program for Mineral Producers. Both articles appeared in Mining Engineering. He is presently employed by Standard Oil Co. of California as a special tax counsel. He holds an LL. B and an LL. M from George Washington University and a Bachelor of Science in Mining from the University of California. He has been chairman of the Taxation Committee of the Minerals Economics div. of the AIME. Borden fishes, plays golf, prospects, and performs mineral analysis as hobbies. [ ] Charles C. Towle (co-author, Uranium Deposits of the Grants District, New Mexico, P. 1037) graduated from the Colorado School of Mines with a degree in Geological Engineering. He was a member of Sigma Nu; Theta Tau, an honorary professional society; Blue Key, honorary social society; the glee club and quartet, and a member of the student council. He has been a mucker, driller, flotation operator and mill shift boss for the Clear Creek-Gilpin Co., Idaho Springs, Colo.; Geologist, chief engineer, and chief geologist for Patino Mines & Enterprises Consolidated, Inc., Bolivia; appraisal engineer and part-time geology student, Denver; office geologist for Geology Dept., special Engineering div., Sea Level Canal Studies, Panama Canal; and geologist, div. of Raw Materials, USAEC, Grand Junction, Colo. He is currently chief of the Denver Exploration Branch, div. of Raw Materials, USAEC, Denver. Towle was at one time a tournament golfer, playing three and four times a week. While working in South America he played in numerous tournaments. Today, although playing only occa sionally, he shoots in the low eighties.

Jan 1, 1952

By R. G. Woolery

INTRODUCTION Since 1975, Union Carbide Corporation has been conducting uranium exploration in southwestern South Dakota. This program has resulted in the discovery of an ore body about eight miles north of Edgemont in Fall River County. The site which was previously mined for uranium in the 1950's and 1960's consists of 950 lode claims (approximately 20,000 acres) and is within the Black Hills National Forest. Preliminary development plans indicate that fewer than 200 surface acres will be involved in the mining and heap leaching of the ore. The ore occurs in both the Fall River and Lakota formations. The exploration to date has developed something in excess of two million tons of ore averaging -0.1% U308. About 75% of the ore is expected to be mined from underground with 25% coming from five to seven small pits. The surface mining will be extensions of previously mined areas with a disturbance of 35-40 new acres near 35-40 previously disturbed acres requiring a total reclamation of 70-80 acres. Several options for processing the ore including conventional milling by UCC, conventional milling in joint venture with another producer, and heap leaching are under consideration. This paper is concerned with the preliminary assessment of the heap leaching option based on the limited test work conducted on surface samples and on available cores from the deeper ones. The final design for a commercial operation will not be available until an underground bulk sample has been obtained and evaluated. Union Carbide has been operating heap leach facilities commercially since 1973 at Gas Hills, Wyoming and Maybell, Colorado. During this period, we have made considerable progress in heap construction

Jan 1, 1983

By R. W. Raymond

Since the foregoing paper (see p. 387) was printed, I have received the decision of Judge William E. Church, of the first District Court of Dakotah, in the case of Michael Duggan et al. v. John H. and Frank J. Dnvey (Silva Terra—Sitting Bull case), published in full in the Black Hills Weekly Pioneer of August 9th, 1584. The journal mentioned gives also several interlocutory decisions rendered in earlier stages of the case; but I shall quote here only so much of the final decision as bears upon the .construction of the Revised Statutes concerning the apex, the end-lines, and the extra-lateral mining right, together with a sufficient statement of the facts of the case to explain the scope of the decision. " This is an action in equity, brought in the first instance to restrain a threatened trespass by the defendants upon certain mining property in the possession of the plaintiffs, known as the ' Silver Terra' claim ; the allegation being that the defendants were about to enter, through underground workings, the ground of the plaintiffs, and remove therefrom valuable bodies of silver ore. " The answer of the defendants, admitting the acts constituting the alleged threatened trespass, further averred that they had, in fact, at the time complained of, reached and passed, in their underground workings, throngh and beyond the vertical side-line of the Silver Terra claim, and therenpon justified the acts complained of, and claimed the right to pursue their workings into and through the Silver Terra ground, by virtue of their alleged proprietorship of a vein, lode, or ledge of rock in place, hearing silver, having its top or apex within the lines of a certain other mining claim called the ' Sitting Bull,' of which they claim to be the owners, which vein, lode, or ledge extended in a continnons body of mineral-bearing rock from such top or apex to the ground in controversy, and constituted the body of ore in dispute; and that it was in the pursuit of this vein, lode, or ledge in its downward course that they had passed beyond the vertical side-lines of the Sitting Bull claim, and for some hundreds of feet beyond, into the ,ground in controversy " Subsequently, a supplemental complaint was filed, setting up the entry into plaintiffs' ground by the defendants, and their claim of right to do so, and asking fnrther relief by a decree restraining the assertion of such claim, and quieting the title of plaintiffs. "The case was tried before the court without a jnry..... " Custer hill, upon which these claims are located, is situated in the village of Galena, in Bare Butte mining district, in this county. The village lies at the base of the western slope of the hill, which presents a lateral face from south to north

Jan 1, 1884

By E. K. Olson

Eagle Mountain mine of Kaiser Steel Corp. began production in 1947 when the direct shipping ore contained 51-56% Fe. The high grade, wide ore face and low stripping ratio ores were rapidly depleted and Eagle Mountain required processing plants for upgrading and more efficient mining equipment. During 1970-71 total annual pit tonnage averaged 56 million tons of material ranking the Eagle Mountain Mine as the fourth largest in the country. Ore production averaged 12.5 million tons requiring a stripping ratio of 3.5: 1. During this period mining activities were scheduled for a three-shift, seven-day operation. The present mining rate is about 30 million tpy on a two-shift, five-day schedule.

Jan 12, 1972

By Persifor Frazer

There is always a difficulty in assigning limits to the scope of a science or art, and among the dificulties of that kind besetting practical or stratigraphical geology is that of determining what kinds of natural objects shall be considered as the goals of its search. The term mineral, in its broader sense, includes every solid, liquid, or

Jan 1, 1978

HenRy Clay FRick, a pioneer in modern coke and steel industry and, in more recent years, one of the outstanding financiers of America, died on Dec. 2, 1919, at his home on Fifth Avenue, New York. Although he had been ill since election day, when he had an attack of indigestion which developed into ptomaine poisoning, his death was a surprise to all. He is survived by his widow, Adelaide Howard Childs Frick; a son, Childs Frick, one unmarried daughter, Helen C. Frick, and four grandchildren. A quiet funeral service was conducted at the Frick home on Wednesday afternoon by the Rev. Dr. Leighton Parks, pastor of St. Bartholomew's Episcopal Church. This was attended by members and very intimate friends of the family, Trustees of the Metropolitan Museum of Art, Officers of the Links Club, and Directors of the United States Steel Corpn. Henry Clay Frick was born Dec. 19, 1849, in West Overland, Westmoreland Co., Pa. His father, John W. Frick, was a farmer of Swiss ancestG, and his mother, Elizabeth Overholt Frick, a member of an old Mennonite family. Until he was sixteen, he spent his time at school, on his father's farm, and in his grandfather's distillery, where he kept books. He attended Otterbein University, in Ohio, for a year. Frick, learning that coke was an essential of the already rapidly developing steel business, early invested every cent he could get in coking-coal lands. With the help of an associate of his grandfather, he formed the corporation of Frick & Co., coke dealers, and acquired fifty-one ovens in the Connellsville region and 300 acres of soft-coal lands. During the panic of '73, with the help of Judge Thomas Mellon, a Pittsburgh 'banker, he bought out his partners and while coke was selling at 90 cents a ton enlarged his purchases of suitable lands. Later, the price of coke increased until it was selling at $5 a ton. Before he was 30 years old, Frick was rated a millionaire. Association with CaRnegie In 1878, he sold an interest in the business Do E. M. Ferguson of New York, and later a share to Mr. Ferguson's brother. Four years later the business was reorganized into the H. C. Frick Coke Co. with vast coal lands, great banks of ovens, and a capitalization of $2,000,000. Then began his association with Andrew Carnegie. He exchanged a part of his coke interest for shares in Carnegie Brothers of Pittsburgh,

Jan 1, 1920

By C. O. Bundranl, Peter Dehlinger, W. H. Browne

Brief laboratory investigations are described which attempt to determine optimum .sand concentrations in gel-sand and oil-sand1 well-treatments. The investigations apply to the case where sand acts as a propping agent in formation fractures. Both analytically and experimentally it is demonstrated that optimum sand concentrations can be defined. It is difficult to translate laboratory results to field treatments, however, since the relative distribution of sand and fluid in fractures may not be the same as injected. This is because fluid may penetrate the furtherest narrow portions of fractures, which would not pass sand. Optimum concentration of a monolayer of Ottawa sand in fractures of 0.025-in. width at the usual range of pressures encountered in treatments appears to be about 95 to 2 lb/gal. of gel. An investigation of abrasion of rock-walls by sand in treatments, described in the Appendix, shows that such abrasion is not probable in significant amounts. INTRODUCTION Experience in the Spraberry formation of West Texas, as well as in other formations, has shown that. sand is a necessary and vital part of gel-sand and oil-sand treatments. Many observers of treatments have also concluded that there seems to be an optimum range of sand concentration for these injections. Brief laboratory investigations were made at Battelle Memorial Institute to study flow in fractures with different sand concen- trations. To investigate the existence and range of optimum concentrations in the laboratory, however, necessitates knowledge of the mechanism by which the sand aids in increasing subsequent production. The action of sand in fractures is usually thought to be either that of a propping agent, thus providing a greater effective formation permeability; that of an abrasive in eroding fill material in fractures; or that of an abrasive eroding rock-wall irregularities along fracture surfaces. Investigations described in the Appendix show that sand does not appear to erode rock-wall materials appreciably. In a subsequent paper it is reasoned, at least for the Spraberry formation of West Texas, that the primary action of sand is not in removing fill materials in fractures. In this formation, and probably others, too, the main effect of sand appears to be that of a propping agent. Both analytical and experimental investigations were made for the case of a monolayer of sand acting as a propper, in which sand concentrations were determined that would, after treatment, permit flow of the maximum quantities of oil from the formation into a well. If too few sand grains are injected into fractures in which the bottom hole pressure has decreased appreciably below the original formation pressure, the confining pressure in the formation may become relatively large, thus compress the rock-walls around the sand grains, essentially close fractures, and so decrease the subsequent flow of oil. Similarly, if too much sand is used, the flow of oil will he impeded by the volume of sand present. THEORY Although an analytical approach to determining optimum sand concentrations involves gross assumptions.

Jan 1, 1955

By K. Hanumantha Rao, A. Nayak, . K. S. Narasimhan, S. N. Mahapatra

Selective flocculation studies carried out with iron ore tailings generated at Kudremukh iron ore plant indicate that a concentrate containing 63% iron can be obtained from the tailings containing 34% iron with around 60% recovery. This opens up the possibility of recovering most of the iron lost in the tailings generated at 2 kt/h (2200 stph) while processing 22 Mt (24 million st) ore per year. This would mean that the productivity could increase by around 50%. In these studies, it has been established that caustic degraded tapioca starch is a most effective agent for selective flocculation. While potato starch after caustic degradation can also be used, neither the parent starch nor the amylopectin compound is as effective.

Jan 1, 1986

By V. H. Gottschalk, R. S. Dean

In the theoretical study of metallurgical reactions, it is necessary to make certain assumptions concerning the nature of metal-gas systems. The assumption usually made is that the reaction in such systems takes place predominantly with gas that is in "solution" and that the amount of solution follows the rules which have been developed for aqueous solutions; namely, Henry's law. The purpose of this paper is to inquire whether these assumptions are the best ones that present knowledge of gas-metal systems permits us to make. In the first part the extent to which a gas will dissolve in a metal and still follow Henry's law is considered. The conclusion is believed justified that the number of molecules of gas that can dissolve in a metal and have the system follow Henry's law must be small indeed. It is therefore improbable that the first assumption concerning the predominance of these dissolved molecules in reaction is correct. It is suggested that some improvement in the correlation of the probabilities with the assumptions made in the mass law equations would be made by the use of the dp law of Sieverts in place of Henry's law. However, the amount of gas that may be held in a metal so that it follows either Henry's or Sieverts' law is considerably outweighed in most metallurgical reactions by that held in gas-metal systems of entirely different structures and concerning which little experimental evidence is available. Some speculation concerning the nature of these is offered. The conclusion is that attention should be given to the determining of the nature of gas-metal systems and that the really fruitful application of the mass law and its connected calculations will have to await a more complete knowledge of these systems than we now possess. DISCUSSION (Paul D. Merica presiding) P. D. Merica, New York, N. Y. (written discussion).—The solubility relations of gases in metals, in so far as they are known from the pioneer work of Sieverts and others, have from the first presented certain challenging peculiarities. The authors have emphasized the significance of these characteristics and suggest that they point

Jan 1, 1933