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By Joseph E Pogue

Over a period of years the writer has presented a number of studies1 on various aspects of proration, in a progressive attempt to analyze critically and constructively the economic complexities of this interesting institution, which in a decade has revolutionized the economics of oil production in the United States. In the course of the investigations leading to these papers, the changing nature of proration and the principles underlying its evolution have gradually become clear, so that it is now possible to depart from the analytical method and to construct a synthesis of the steps that, if furthered by the industry, should carry proration past the economic hazards that still surround it to the goal of maximizing the value of the petroleum resource to the industry and the public alike. Nature of Proration Proration literally means the allocation of demand among competing producers on a pro rata basis, but the term now carries a much broader significance for it is employed to describe the entire process by which the production of crude oil in the United States is regulated. There is naturally much confusion of thought on the subject, for proration is an evolving system of control based upon principles of conservation and equity and embracing a body of practices that are tending to adjust themselves to the needs of the situation but are subjected to varying and divergent influences in the process. As it is now constituted, proration is a planned production measure designed to prevent waste, insure ratable takings, and balance supply and demand. The procedure is administered by State regulatory bodies through use of the police power of the States under authority of State conservation laws; the practice is supported by a considerable degree of voluntary conformance on the part of operators; and the Federal Government has accorded its cooperation by providing advisory quotas, circumscribing imports, checking movements of hot

Jan 1, 1939

By Joseph E. Pogue

Over a period of years the writer has presented a number of studies1 on various aspects of proration, in a progressive attempt to analyze critically and constructively the economic complexities of this interesting institution, which in a decade has revolutionized the economics of oil production in the United States. In the course of the investigations leading to these papers, the changing nature of proration and the principles underlying its evolution have gradually become clear, so that it is now possible to depart from the analytical method and to construct a synthesis of the steps that, if furthered by the industry, should carry proration past the economic hazards that still surround it to the goal of maximizing the value of the petroleum resource to the industry and the public alike. Nature of Proration Proration literally means the allocation of demand among competing producers on a pro rata basis, but the term now carries a much broader significance for it is employed to describe the entire process by which the production of crude oil in the United States is regulated. There is naturally much confusion of thought on the subject, for proration is an evolving system of control based upon principles of conservation and equity and embracing a body of practices that are tending to adjust themselves to the needs of the situation but are subjected to varying and divergent influences in the process. As it is now constituted, proration is a planned production measure designed to prevent waste, insure ratable takings, and balance supply and demand. The procedure is administered by State regulatory bodies through use of the police power of the States under authority of State conservation laws; the practice is supported by a considerable degree of voluntary conformance on the part of operators; and the Federal Government has accorded its cooperation by providing advisory quotas, circumscribing imports, checking movements of hot

Jan 1, 1939

By Robert Wamsley, W. E. Jones

ONE of the earliest problems in the life of any community is the provision of an adequate supply of water sufficiently free from all types of contamination to be suitable for domestic purposes. Generally speaking, the location of most communities is determined to a great extent by the availability of an adequate supply of satisfactory water. For a mining camp, that consideration cannot be foremost. Here, the ore takes first place, and the men who mine it must do the best they can under the existing conditions. If there is no local source of water, it must be brought from some distant source or must be found by sinking shafts or drilling wells. Fortunate indeed is the mining company that discovers a commercially valuable ore deposit beside a never failing creek full of pure water, with sufficient water rights available, because the acquisition of water in any other manner nearly always involves not only a considerable period of time but the expenditure of considerable money. The experience of Climax Molybdenum Co. demonstrates the measures that sometimes are necessary in order to provide a suitable supply of water. The Climax mine and mill are on the Continental Divide, about 13 miles northeast of Leadville. The elevation of the domestic part of the camp varies from a minimum of 11,320 ft. to a maximum of approximately 11,550 ft. above sea level, and, as is common at such altitudes, the near-by streams that might be suitable for a water supply are small and intermittent, usually flowing only during the summer months. The only streams of any size in the immediate vicinity of Climax are the Ten Mile and Arkansas Rivers. The headwaters of Ten Mile River are on the Company's property, and its water has been used for the domestic supply. The headwaters of the Arkansas River are about 2 miles distant and have not been used as a source of supply by the company. During the past 11 years of the production of molybdenum at-Climax, the number of families living there has increased from about 45 to 283, and the population has increased from about 200 to 1200 persons. Consequently, the capacity of the water-treatment facilities, and the amount of water available, had to be increased to meet the requirements of the camp. As early as 1932 it was recognized that the water in Ten Mile River would not continue to be adequate for domestic purposes and after considerable discussion it was decided to drive a drift through the major fault in an effort to find additional water. This drift was completed in 1935 and tapped sufficient water to make the supply adequate. This water was treated in a tank underground, where lime was added, and was then piped into the domestic supply lines. At about the time this line was completed, the presence of fluorine in harmful concentrations was discovered in the water. This problem was submitted to the International Filter Co. and in November 1937 a plant of its design was put in operation for treating the water to remove the fluorine. This plant proved entirely successful,

Jan 1, 1945

By H. F. Johnson, C. S. Harloff

The Nichols series system of electrolytic copper refining has successfully maintained its strong competitive position in the copper-refining industry of today; therefore the improvements made in accomplishing this result are of interest. While additional interest would lie in specific comparisons of results obtained in series operation with those in multiple, we have refrained from such a comparison because it can be fair to both only when they are operating under similar conditions on the same grade of materials. Historical The Nichols Copper Co. started a small refinery at Laurel Hill, using its present system, about 1892. The details of the process in its early stage of development were kept strictly secret, so that no information was published or interchange of ideas permitted with the staffs of other copper refineries, where the multiple system was being developed at the same time. However, the fundamentals of the process and type of cell used today differ very little from their earliest form. All operations including loading and unloading of tanks, and all transportation as well, were carried on by hand. The plant remained in this condition with a gradual expansion taking place until the World War forced such a rapid development that little time or thought could be devoted to modernization or mechanical improvement requiring careful design or detailed planning. Considerable progress was made, however. (1) Large refining furnaces were developed. (2) The old expensive air-lift type of circulation was abandoned in favor of the present system. (3) Operating technique was gradually developed to a high point of efficiency. (4) Tank construction and lining were greatly improved, the first concrete tank being installed in 1915. (This tank is still in operating condition.) (5) A new power plant was constructed. (6) Fuel oil was substituted for lump coal on the refining furnaces. (7) Mechanical casting of the finished product was accomplished. During this entire period the plant was particularly fortunate in receiving only high-grade, clean copper bullion coming principally from the Phelps Dodge mines in Arizona. This, together with the lack of

Jan 1, 1934

By AIME AIME

AMONG the industrial motion pic¬tures released in the last year of possible interest to people in the mining industry are the following: "A New World Through Chemistry," made by the public relations department of E. I. du Pont de Nemours & Co., Wilmington, Del. This film, which is in sound and color, interprets in twenty minutes of narration and ingenious photography many of chemistry's newest developments. It may be borrowed either in 16-mm. size on an 800-ft. reel, or 35-mm. size on a 2000¬ft. reel, the only charge being the cost of returning the film. Douglas D. Rothacker, 729 Seventh Ave., New York City, is prepared to loan free of charge except for transportation each way several films prepared in the plants of the International Nickel Co., 16 mm. with sound. These include: "Nickel High Lights," 35 minutes; "Nickel Mining," 18 minutes; "Nickel Smelting," 18 minutes; "Nickel Refining," 9 minutes; and "Copper Refining," 6 minutes.

Jan 1, 1941

By K. Stout, E. Van Eeckhout, L. Friel

Previous research at the Montana College of Mineral Science and Technology indicated that it is practical and economically feasible to place stiff back- fill in a cut-and-fill stope. This backfill would reduce wall closure and high stress buildup in pi1llars, thus alleviating rockburst potential. Three ;topes from the Sunshine Mine, of the Coeur d’Alene Mining District, were chosen for a test verification of this concept. Although the first stope was lever mined beyond the initial cut (for economic reasons), some vibrating wire stressmeter results were obtained and found to compare favorably with numerical predictions. Some other instrumentation devices were built and tested, but never installed .

Jan 1, 1984

By L. E. Tanner

A study was made of the transformation kinetics of the commercial titanium-base alloys, Ti-2.5Al-16V and Ti-4A1-3Mo-1V, using two different heat treatment cycles: 1) step-quenching to aging temperatures from a ß solution anneal and 2) water-quenching from an a+ß solution anneal followed by reheating to aging temperatures. Metallographic examination and hardness testing provided the major portion of the data, while electrical resistivity, dynamic elastic modulus, and X-ray diffraction techniques were also used to obtain critical or confirnzatory data. TTT diagrams were constructed from these results. The sheet alloys, Ti-2.5Al-16V and Ti-4Al-3Mo-lV, are of current interest to the Department of Defense. As an aid to the planning of their respective heat treatments, a program was carried out to determine the transformation kinetics of these alloys using ß and a + ß reference states. This paper presents the TTT diagrams constructed from data obtained by metallographic examination and hardness testing, as well as by X-ray diffraction, electrical resistivity, and dynamic elastic modulus determinations. EXPERIMENTAL PROCEDURE Materials—Sheets of the alloys were obtained from the producers in the "mill anneal'' condition and were tested prior to shipment to assure their meeting mill specifications. Chemical analyses were also supplied and are presented in Table I. Heat Treatment—The majority of the data presented in this study were obtained from hardness testing and metallographic examination. Sample coupons were cut from the alloy sheets and heat treated on a mass scale. The annealing cycles were operated in the following manner: 1) The ß solution anneals were carried out in a horizontal tube furnace with the bare samples protected by a dynamic helium atmosphere. Following this treatment, the samples were quickly transferred to lead, solder, or oil-bath furnaces for aging. After prescribed times at the various reaction temperatures they were water-quenched. 2) The second cycle simulated commercial practice, which requires the alloys be quenched to room temperature following the a + ß sotution anneal. This anneal was carried out in a muffle furnace with a dynamic helium atmosphere. The specimens were then reheated from room temperature to the reaction temperatures in lead, solder, or oil-bath furnaces, followed by water-quenching after prescribed times at these temperatures. Information concerning the critical temperatures of the alloys was obtained from the literature and solution treatments were based on these values. A summary of the solution annealing treatments is found in Tables II and 111. The aging temperatures for the (a - ß alloys ranged in 50°C intervals from 200°C (392oF) to approximately 50°C below the ß/a + ß transus in the first cycle and approximately 50°C below the a + ß solution temperature in the second. The transformations in these alloys were known to be rather rapid, and thus aging times started at 0.5 min and went to a maximum of 7000 min. Hardness Testing and Metallographic Preparation— Heat-treated samples were sheared and mounted in Bakelite with their cut edges exposed. After a flat surface was ground, the hardness was determined in Vpn on an Armstrong-Vickers machine utilizing a 20-kg load. Three to four impressions were made on each specimen. After this procedure, the hardness impressions were removed and the edge surfaces of the specimens were prepared for metallographic examination in the usual manner. The etchant was 20 pct HF and 20 pct HNO3 in glycerine. Electrical Resistivity—It has been shown that the isothermal reactions in titanium-base alloys can be followed by measuring the changes in e1etrical resistivity attending these transformations. As mentioned earlier, the reaction kinetics of a-ß alloys are rather rapid; thus, it would be expected that resistivity data obtained from these alloys would be more significant if measurements were made continuously at the respective aging temperatures. To accomplish this end a special apparatus, based on the current-potential principle, was assembled. Its design was derived from earlier devices constructed by Colner and zmeska1 4 and Levinson.5 The set-up provided for the heat treatment zof machined specimens (approximately 2 x l0-4in. in cross section by 3 in. in length) and the determination of their relative

Jan 1, 1962

By H. M. Chance

In recent years an important function of the mining engineer has been the appraisal of the value of mining-properties required by those planning consolidations of a number of' individual operations. In no field of productive industry have the economic results attainable by consolidation been more clearly shown than in the mining-regions of the United States. In many important mining-centers unification of ownership of the most valuable properties has already partially or completely been attained, and, in other districts, projected absorptions and consolidations await only favorable financial conditions for their consummation. The iron-ore districts of the Lake Superior region, the coal-mines of Colorado, of Wyoming and of Utah, the anthracite mines of Pennsylvania, the Connellsville coking-coal mines, and large areas of bituminous coal-land in Pennsylvania, in Ohio, in the Indian Territory and in other portions of the United States, are now largely controlled by a few corporations operating on a large scale, or by a number of corporations working in harmony because of an affiliation and interleaving of interests. The tact of keen financiers and the diplomacy of men of great administrative ability are the chief operative forces in conceiving and accomplishing such consolidations, but in formulating and maturing them, the services of the mining engineer are often required to supply the facts upon which they must be based. For this purpose the expert is expected to furnish full and complete reports covering the quantity of ore, coal or other mineral available, its value per ton, cost of mining and treatment, etc. In reporting upon gold-, silver-, lead-, zinc-, copper- or iron-

Jan 1, 1905

By Young C. Kim, Francis Martino, Ish Chopra

For the past two and one-half years, various emission control strategies were jointly developed by the University of Arizona and the Homer City Owners to com- ply with the clean air requirements at its Homer City Power Plant. Some of the available options for the SO2 emission control by the Homer City Owners were:l)cleaning of run-of-mine coal,2) scheduling of mining operations at its captive mines, 3) blending the captive mine coal with externally purchased low sulfur coa1,and 4) placing a partial FGD system. This paper describes two specific emission control strategies developed and implemented. These are: 1) production scheduling at the mining face to minimize sulfur variability, and 2) external purchasing of low sulfur coal for further blending. The main objective of this paper is to share our experiences on implementing the developed strategies. This paper emphasizesthe need for proper mine planning on a short-term basis, if the power plant is to meet the desired objective.

Jan 1, 1983

By Y. C. Kim, I. K. Chopra, F. Martino

This paper reviews geostatistical work in a coal deposit performed jointly by the University of Arizona and the Homer City Owners. The study objective was to Predict more accurately the inseam sulfur values of the deposit for the purpose of future emission control. Based on initially available 112 DDH information, variogram models were developed for sulfur, ash, and thickness for the entire deposit. The deposit was then kriged using 333 m x 333 m panel size. Kriging produced better results than conventional isopachs. The estimation variance information obtainable from geostatistics was then used to improve development drilling activities that were underway. This effort was successful. Up-to-date experience on the use of conditional simulation of the deposit appears promising for future emission control strategy development

Jan 1, 1982

"Minerals in Transition" is the timely theme of this year's SME-AIME Fall Meeting and Exhibit, to be held September 10-12 at the Salt Palace, Salt Lake City, Utah. Approximately 2000 members and guests are expected to attend the meeting, which will include 117 technical papers, presented during 27 sessions. To complement the technical program, a record number of mining manufacturers and suppliers will be on hand to exhibit the latest in equipment innovation and professional services.

Jan 8, 1975

By J. L. Jernegan

IN a former paper laid before the Institute, entitled Lead and Silver Smelting in Chicago, I endeavored to give a description of the manner in which argentiferous lead ores from the far West were treated in that city, and also described the method employed in the desilverization of the silver-lead produced from the ores. It will perhaps be remembered, that very siliceous ores, principally from the Emma mine, Utah, containing over 40 per cent. of silicic acid, were then being treated at the works of the Chicago Silver Smelting and Refining Company in the reverberatory furnace, with the use of metallic iron, in the form of borings, as a precipitating medium for the lead ; and that the extraction of the silver from the resulting bullion was effected by the Balbach process. The Swansea Works, also the works at Brighton, just outside of this city, and those of S. P. Lunt, were at that time treating ore of a similar character by the same method. The inadequacy of the process for the ores then under treatment was, in a manner, pointed out by me in the paper above referred to. Since the time of its writing, many and important improvements have been made in the metallurgical treatment of Western ores in Chicago. Most ores are now roasted previous to reduction, and the latter operation is conducted in the shaft-furnace instead of the reverberatory. Such is the fact at least at the Swansea Works, the largest in the city, and here it was where the first steps were taken in this direction. In selecting these works as the subject of this paper, I am in hopes that the description given of the various metallurgical operations, as they are there now conducted, will serve to give an idea of the improvements introduced

Jan 1, 1876

By M. E. Wadsworth

The chief value of a paper like this consists in its statistical tables, putting on record material useful to future inquirers. The data here given have been compiled from time to time as far back as 1874, and subsequently brought up to date. Much of the data could only be procured by personal inspection of the catalogues, as for example those relating to the Lawrence Scientific School, which were taken at that time from the catalogue of Harvard University, on file in the University Library, by the present writer, then an instructor in that institution. These tables of statistics were first prepared for publication by the present writer in 1888-1890 and published in his "Report to the Board of Control of the Michigan College of Mines " (Michigan Mining School) for 1886 to 1890. Later they were revised, enlarged and brought down to date in his reports to the same Board for 1890-92; and since that time they have been, at his request, revised, greatly enlarged and kept up to date by Mrs. Frances H. Scott, the efficient Librarian and Secretary of the Michigan College of Mines. Great credit is due to her for her devotion to this work and her untiring efforts to have the statistics complete as far as possible. The accompanying running commentary is given simply as a string to hold these statistics together, and in order to call attention to a few points. In compiling any tables like those accompanying this paper, one is confronted by serious difficulties, some of which render these results only approximate. In order to insure greater correctness and fullness in the statistics to be published the writer's reports for 1890-92 were sent to the president of every college, university, and technical school in the country, so far as known. Accompanying this was a personal letter which asked of each one his aid in correcting any errors, and in giving fuller statistics. But relatively few answers were obtained, and subsequently from one to many letters have been sent to each institution not formerly reply-

Jan 1, 1898

By F. C. Stanford

THE work of an engineer is to direct natural forces so that they bring about the results that he wishes to secure. Heretofore he has concerned himself chiefly with physical forces and inanimate objects, until he has secured a truly marvelous degree of control over them. The great problem of the present age is to secure a like degree of knowledge and control of the human factor. Progress has already been made along this line, but, it is only a beginning. Wilhelm Ostwald says that scientific knowledge enables a man to be a true prophet; but it must be remembered that a good many people do not seem to be able to maintain a high average in prophecy. In short, the average of knowledge is not equal to the average needs of the present time, but continually fails to keep pace with it. It has been aptly said that the really essential need of the period is for more brains; if we only had sufficient knowledge and sagacity we could not only solve all difficulties, but prevent them from arising. This generalization holds good for an industrial organization. The most vital need of the management is for more brains. The logical course for an engineer in charge of an industrial organization is, therefore, to direct whatever forces may be at his command toward the development, training, and guiding of all the brains in his organization. This is easier said than clone, for it involves the carrying on toward two objectives, the maximum of productive work, and the development of the individuals who perform it. This is essentially like the rebuilding and enlarging of a plant, keeping it in full operation the while. On the other hand, if the aim is merely for maximum production from an organization, without offering opportunity for development, the final outcome will necessarily be like that f a plant that is driven at full capacity without stopping for repairs or improvements; it eventually becomes so run down that either a complete rebuilding is necessary or else it has to be abandoned.

Jan 2, 1918

By Frances Jane Cromwell, D. J. McAdam, G. W. Geil

INTRODUCTION IN a series of papers, the authors and their associates have shown that the technical cohesion limit is affected by the same four factors that affect the flow stress, namely, the stress system, plastic deformation, temperature, and the strain rate.16-28 Moreover, each of these factors affects the technical cohesion limit in the same way that it affects the flow stress.‡ The influence of any one of these factors may be represented by a curve of cohesion limits, although only one point on the curve may represent actual fracture. As the term "fracture stress" has come into use with the same significance as "technical cohesion limit," the authors are here using the shorter term with the understanding that it does not always refer to actual fracture. This paper presents the results of an investigation of the flow of notched and unnotched specimens between yield and fracture. A study has thus been made of the flow and fracture of metals as affected by the stress system, and of the ductility of metals as affected by the stress system throughout plastic deformation. Since two of the principal stresses were equal (S2 = S3), the stress systems can be represented in terms of the radial stress ratio, the ratio of the transverse radial stress S3 to the longitudinal stress Sl.* The results of the experiments are represented by a series of complete flow-stress curves for each of the metals investigated, and these diagrams have been used for the development of other diagrams of various types. Ludwik was the first to suggest that fracture occurs when the flow stress becomes equal to a technical cohesion limit. Although Ludwik was incorrect in his view that the technical cohesion limit depends only on the amount of plastic deformation and not on the stress system, he was correct in his view that the flow-stress curve for any stress system terminates at a point representing a technical cohesion limit. The authors have seen some recent references to assertions by other investigators that a point representing the fracture stress need not be on the flow-stress curve. The Ludwik principle, however, would seem to be axiomatic, provided that the flow stress and fracture stress are properly defined and that the fracture stress is properly determined. Disregard of this principle has led to some untenable theories of criteria for fracture. When a metal is very ductile, the conventional method of determining the ductility and fracture stress by dividing the breaking load by the sectional area after fracture, generally gives values that are much too high. With some metals and in some conditions, the fracture stress thus determined may be two or more times the

Jan 1, 1948

By Paul A. Beck, M. N. Parthasarathi

By determining the (220) pole figure for OFHC copper rolled to 96 pct R. .A., the occurrence of four texture components of the type (135) [211] was confirmed. It was found that the total volume fraction of material close to the four symmetrical orientations of this type is larger than the volume fraction of the other components put together. THE rolling texture of copper was described by early investigators1'" as a mixture of components of the (110)[l12] and (112) [11l] types. Other studies, still using the qualitative photographic method of texture determination arrived, instead, at orientations of the type (135) [533] or (135) [211] for copper3'4 and at the closely related "Z-texture" for a fee nickel-iron alloy.5 The prevalence of this type of orientation, near (123) [412], in the rolling texture of aluminum and of copper was later confirmed by means of quantitative diffractometer methods.' However, in a recent paper7 Jones and Fell stated that the (110) [112] and (112) [111] double texture was in better agreement with the measurements of Young's modulus for cold-rolled copper.' These authors also expressed their belief that the "roll texture" can be determined by means of two photographic quasi-fiber texture patterns taken with sheet specimens rotated around the rolling direction and the transverse direction, respectively. Jones and Fell found7 that the results obtained from such patterns for cold-rolled nickel did not agree with any of the orientations mentioned above, but they suggested that the observed diffraction spots may have been brought about by the overlapping of reflections due to the (110) [112] and (112) [11l] double texture components. Jones and Fell concluded that the (123) 14121 type orientation is inconsistent with their patterns. They also stated, without offering any supporting evidence, that this orientation is inconsistent with the (220) pole figure. "Ideal orientations" are often used for a very rough description of the principal orientations encountered in a texture, It is, however, well to remember the fact that, no matter how "accurate", these ideal orientations are only schematic representatives of a continuous distribution9, which often (as in the case of rolled copper) includes extensive orientation spreads. The attempt by Jones and Fell7 to use elastic modulus data in deciding between various ideal orientations in the rolling texture of copper neglects this fact. The inadequacy of two-dimensional "axis density figures" in describing orientation distributions in sheet textures was previously discussed.9 It was also pointed out9 that there is no reliable evidence to prove that orientation distributions derived by the "quasi-fiber method" from rotated sheet specimens are fully equivalent to the corresponding information obtainable from quantitative pole figures. The view that a sheet texture could be adequately determined by means of two photographic quasi-fiber texture patterns is obviously erroneous9. The question as to the consistency with the (220) pole figure of ideal orientations derived from the (111) and (200) pole figures is, on the other hand, certainly very relevant. Since no quantitative (220) pole figure for cold-rolled copper appears to be available in the literature, the following work was undertaken. EXPERIMENTAL METHOD An extruded rod of OFHC copper, 1 in. in diam, was given alternate rolling (30 to 35 pct R.A.) and

Jan 1, 1962

By Elmer A. Jones

Development work in mines of St. Joseph Lead Co., Southeast Missouri, using trackless loading equipment shows definite advantages: Speed of cleaning, ability to work on steep grades and sharp crosscuts, good later tracking conditions, and possibility of wasting rock in old abandoned stopes.

Jan 1, 1950

Welfare endeavor in connection with both the metal and the coal mines of Utah has shown gratifying progress during recent years and both the operators and their employees are deserving of much credit for the efforts put forth to better living, working, educational and receational conditions in most of the mining camps of the state. In the older metal mining camps of Utah, where the towns are incorporated and independent of the mining properties operating in the vicinity, less opportunity is presented for the companies to exercise efforts looking towards improved welfare conditions than is the case of camps located on company ground and under the full control of operators.

Jan 1, 1925

By George J. Simchuk

Selection of an applicable stripping method and the subsequent determination of appropriate sizes of selected equipment are discussed. The case in point is Utah International, Inc.'s Goonyella mine located in central Queensland, Australia. A detailed study of the various types of stripping methods now practiced throughout the world led to the conclusion that large draglines would be the logical choice for Goonyella. The optimal size of dragline was then determined by first designing a series of cut diagrams using an array of machine and pit geometries followed by a cost comparison of the various sizes of machines, in terms of their effective spoil radius. A dragline with a 51-cu-yd bucket was determined to be of optimum size. Further calculations, incorporating total overburden moved from both the highwall and spoil sides, required that four drag lines, two equipped with 40-cy-yd buckets and two with 54-cu-yd buckets, be used to satisfy the stripping requirements at Goonyella.

Jan 1, 1973

By W. Bradley, R. G. Hall

This paper will attempt to show how a metallurgical problem at one California quicksilver mine was solved, and how the solution was applied successfully at another mine. The pronouns "we" and "our," as used below, refer '0 the Bradley 'lining Co. of San Francisco. The term "concurrent firing" for the purpose of this paper can be defined as feeding and firing a a kiln at the same end—that is, of course, the upper end' This is as opposed to "countercurrent firing," the orthodox method, in which a kiln is fed at the upper and fired at the lower end. The terms "quicksilver" and "mercury" are used interchangeably. Early References The earliest work on nonferrous metallurgy, we believe, was The Pirotechnia of Vannocio Biringuccio,l its first edition having been printed in Italy in 1540. Quoting from its chapter entitled "Concerning Quicksilver and Its Ore": Quicksilver ... is one of the gods and has divine strength in itself, and also, to the annoyance of the alchemists, it is winged. Hence, when it sees that it is in gravest danger, it loosens itself from . . . every bond . . . and fies away into the heavens, escaping from the hands of those who crucify it. Almost laughing, it leaves all its adversaries mocked and scorned, with their phials and filters empty . . . How thorough a job, under certain conditions, it can do of mocking its adversaries and leaving their phials and filters empty, was found out four centuries later at the Sulphur Bank mine, on the east shore of Clear Lake, in Lake county, California, The other mine mentioned in the title is the Reed, in Yolo County, California, 35 miles by road southeast of Sulphur Bank, Reed and Sulphur Bank ranked respectively Nth and seventh in U. S. production in 1943. The earliest direct reference we can find to furnacing troubles at these mines was by Thomas Egleston in 1890.2 Speaking of Sulphur Bank, Egleston says: of there is more sulphur than cinnabar in the ore, which is a detriment to both . . . making the sulphur impure, and rendering the cinnabar difficult to work on account of the soot. In some of the early . . . furnaces the accumulation of soot from the excess of sulphur has been known to penetrate as far as the fan blower at the end of the . . . condensers, and completely prevent its revolution. In order to get rid of the inconvenience of this accumulation . . . , as well as to get a commercial value from the sulphur, it (the sulphur) is now separated by steam and sold. It is claimed that the sulphur alone pays all the expenses of ... the mine. The mine was first worked for sulphur, and the cinnabar it contained was considered to be an inconvenience, and was carefully picked out and thrown away, as its richness and value were not

Jan 1, 1949