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By George W. Friesen

This paper presents the historical trend and de- fines the causes of drilling cost escalation in the Gulf of Mexico during the 1970's. The three major components of escalation are: 1) inflation, 2) supply-demand imbalance (demand pull) and 3) decreases in drilling efficiency. The decade was divided into three periods. During each period one component of escalation was responsible for most of the rise in costs. From 1970 through 1973 only inflation pushed costs upward. During 1974 and 1975 a supply- demand imbalance caused most of the escalation. Since 1975, decreases in drilling efficiency have produced the major component of escalation. During any one year or period of years, the sum of the three components will give the total escalation rate. The reasons why different components contribute more toward escalation during certain years than others are shown by following the timing of oil and gas price increases, the overall quality of the acreage offered each year in offshore lease sales and the resulting drilling activity.

Jan 1, 1982

By J. F. KENP

THE White Knob copper-deposits are situated about three miles south of Mackay, on the Salmon River .branch of the Oregon Short Line Railroad, in Custer county, Idaho. An outline-map of this district is given in Fig. 1. The deposits have been known and spasmodically worked for many years, and a total of over 3.5 miles of tunnels, shafts and other workings has been driven with a view to their development. These extensive excavations have exposed the deposits sufficiently to permit a careful geological examination. The peculiar features which give special interest to this paper are the branching, free-like form of the ore-bodies; the absence of zones of secondary enrichment in the partly oxidized pyritic deposits, and the fact that while the deposits are associated in a general way with the contact of an eruptive rock with limestone, which it penetrates, the garnetization has taken place not in the limestone, as is the usual case, but in the igneous

Mar 1, 1907

By JAMES J. PURDY

The great majority of stokers used in residential heating installations are of the clinkering type. Because of inherent characteristics of the under- feed combustion process as it occurs in these small stokers, and because of the wide range of operating conditions encountered in residential heating schedules, not all bituminous coals can be used successfully in residential underfeed units. The problem of providing consumer satisfaction has been attacked by the joint efforts of the stoker manufacturers and the coal industry; the stoker manufacturers have been concerned with improving their product to permit the use of a wider range of coals, and coal operators have made every effort to market selected and better prepared coals. In view of the wide range of physical characteristics and chemical properties of bituminous coals, the problems are real and are receiving increased attention.

Jan 1, 1949

By Michael S. Roscoe

In order to more accurately predict longwall surface subsidence over the Pittsburgh No. 8 Coal in Eastern Ohio, North American Coal Corporation's Quarto Mining Company undertook or participated in several subsidence studies. Due to the changing roof geology and rapid variations in the amount of cover two separate areas were investigated at two different mines to determine the subsidence response if any to these changes. Data generated from these studies were compared with NCB derived,data for accuracy and then used to predict subsidence under houses, gas lines and other critical man made structures. The following report summarizes the results of these studies as well as the subsidence case histories of gas lines, transmission towers, houses and water wells. Problems that were encountered during both phases of this process (investigation and subsequent application) are also included.

By James P. Savely, Victor L. Kastner

Inspiration Consolidated Copper Company is currently mining in four pit areas; Live Oak, Red Hill, Thornton and Joe Bush Extension, near Globe, Arizona. Small satellite orebodies lying outside the main pits have been mined out in a series of small open pits. Major slope instability has affected production in every pit. Some consequences of the instability have been; (1) Serious interruption of mining plans, which resulted in deferred ore production, lost ore, reduced mining rates and increased stripping requirements. (2) Forced replacement of crushing facilities. (3) Serious effects on other production facilities. The introduction of a slope stability monitoring and control function as an integral part of mine planning has been successful in reducing the impact of these failures and will eventually result in economic pit design based on probabilistic slope analysis. This case history presents a brief review of the problems associated with slope instability at Inspiration's mines followed by a more detailed report on one specific failure area in the Thornton pit where the use of horizontal drain holes for slope stabilization appears to be successful. Relationships between slope movement rate, rainfall, and mining activity are shown.

Jan 1, 1983

On the preceding pages, operations of the four major producers of nickel today have been described. There are, however, other operations in the world that, while not as large, are still of importance to the over-all picture of the industry. Among these are the Finnish producer, Outokumpu Oy, a state-controlled company that operates the Kotlahti mine 200 miles northeast of Helsinki. The ore from this operation, which began production in 1959, is pentlandite, chalcopyrite and pyrrhotite, occurring as disseminations in the host rock and in breccias. The flowsheet of the 1500-tpd mill at Kotlahti follows standard practices of crushing, grinding, and flotation to produce a pentlandite-pyrrhotite concentrate and a copper concentrate, both of which are shipped to the smelter at Harjavalta.

Jan 10, 1968

By Henry E. Wood

Cleveland Meeting, October, 1912.) IN my opinion, the concentration of minerals by flotation is the most interesting problem in ore-dressing, and will command eventually far more consideration than it has at present. For many ores it furnishes a complete method of concentration absolutely independent of specific gravity, and thus simplifies the milling of many difficult combinations. Not having to recognize the influence of specific gravity, we are also able to dispense with some of the complications resulting from classifying-conditions. Where flotation cannot be used for a complete separation of the minerals from the gangue, it will be found, in nearly all cases, to save those portions which are generally lost by reason of their fine state of division. For this reason, it should be looked upon mainly as an aid to general concentration, although there are many ores so well adapted to flotation that more than 90 per cent. of the valuable metals can be recovered from them in one operation by this process. In presenting the results of my investigations in. flotation, I have endeavored to theorize as little as possible. That side of the subject has been extensively discussed by others. My earliest work with flotation was done in 1895, when I used various oils, grease, soap, etc., with results that were remarkable. I did not realize then that with water alone equally good separations could be made. Up to 1906, my endeavors were confined to attempts to keep the concentrates on the tables well wetted and away from exposure to the air. In common with others, I observed that when there was any obstruction in. the wash-water on the table of sufficient size to divert the water to either side, the concentrates collected, and, on exposure to the air, would promptly float away. This convinced me that the sulphides were all good " swimmers," and that if,

Nov 1, 1912

By J. W. R. Rayner

THE conventional method of making water gas involves individual plants for the separate carbonization of coal to coke and the subsequent gasification of coke with steam. The process demands lump coke, preferably made from the best quality of coking coals. The ash in the coke should have a high melting point and the gasification process suffers a loss of efficiency when cokes with low ash-melting points are used. In Britain, these coals are generally the most expensive and they are readily available only in certain localities. The coals not suitable for making lump coke, or yielding only poor quality coke, are much more widely available and are generally cheaper. DEVELOPMENT OF ALTERNATIVE PROCESSES In Germany, processes have been developed and operated commercially for the production of water gas from very low-rank coals such as brown coal and lignites, but much less effort has been spent on processes to use coals of intermediate rank, which are widely available in Britain. The brown-coal processes use coal in the form of either dust or briquettes. The most successful of the dust-gasification methods is the Winkler process, which made a substantial contribution to German oil production during the war. It uses coal in the size range 0 to 8 mm and the fuel bed is blown with a mixture of oxygen and steam at a rate high enough to give it a characteristic boiling motion or, in present-day phraseology, at a rate more than sufficient to fluidize it (Fig. 1). Air cannot be used to provide the heat required for gasification, for vari¬ous reasons. In the first place, to make the process continuous by mixing air and steam would involve the production of a lean gas containing much nitrogen. If a separate blow were used, a large amount of potential heat would be lost because the blow gas in such a process would contain a very high percentage of carbon monoxide. Oxygen is necessary therefore and oxygen remains relatively expensive for use in gasification. In the Winkler generator, formation of clinker caused by local overheating does not occur, because of the mobility and high heat transfer of a fluidized bed. These properties of fluidized dusts have been used most successfully.

Jan 1, 1953

By Charles R. Keyes

I. INTRODUCTORY. IN the dry regions of the globe many silver-deposits display certain remarkable features which at the same time are so totally unlike anything met with among ore-bodies elsewhere, that they have long presented exceptional difficulties not only to a satisfactory explanation of their origin, but to economical milling. A most striking peculiarity of these ores is the haloid character of many of their bonanzas. To this fact more than to any other may be ascribed most of the unusual uncertainties of mining-operations in desert countries-the marvelous local richness of the ores under certain conditions and the often abrupt transition, to utter poverty; the inadequacy of ordinary prospecting customs and the constant devising of new exploratory methods; the unaccountable losses in smelting and the continual change in treatment-practice. For these anomalies certain climatic conditions seem to be chiefly responsible.

Jul 1, 1911

By Thomas T., Read

IT will be recalled that the first professor of metallurgy in the United States, appointed in 1855, never really gave any instruction in metallurgy and gradually turned into a professor of mineralogy. Metallurgy was included with. mining in the early curricula, two students who took the B.S. in mining engineering from the Polytechnic College of Pennsylvania in 1862 wrote their graduation theses on the metallurgy of copper and zinc, respectively. Even after Columbia School of Mines established, in 1868, a separate curriculum leading to the Ph.B. degree in metallurgy, very few students elected it,* preferring to take the mining degree, since they received in its curriculum nearly all the metallurgical instruction they would have in the metallurgical curriculum. For many years a large proportion of the men who attained prominence in metallurgical enterprises had taken mining rather than metallurgical degrees. METALLURGY Clifton Sorby's study of thin sections of rocks under the micro¬scope, beginning in 1850, and its subsequent development by Zirkel and others, had made microscopic petrography a recog¬nized department of geological research as early as 1873. . It was inevitable that the idea of studying polished metal surfaces-¬under the microscope by reflected instead of transmitted light would occur to investigators. Sorby himself did it in 1864, and Adolph Martens and Floris Osmond may -be especially named among the many European workers who, by the late eighties, had so developed the, necessary techniques that they were able to photograph polished metal surfaces at magnifications as high

Jan 1, 1941

By J. Handin, S. J. Bauer, M. Friedman

Deformation mechanisms in room-dry and water-saturated specimens of Charcoal Granodiorite, shortened at 10-4s-1, at effective pressures (Pe) to 100 MPa and temperatures to partial melting (?1050°C) are documented with a view toward providing criteria to recognize and characterize the deformation for geological and engineering applications. Above 800°C strength decreases dramatically at effective pressures ? 50 MPa and water-weakening reduces strength an additional 30 to 40% at Pe = 100 MPa. Strains at failure are only 0.1 to 2.2 percent with macroscopic ductility (within this range) increasing as the effective pressures are increased and in wet versus dry tests. Shattering (multiple faulting) gives way to faulting along a single zone to failure without macroscopic faulting as ductility increases. Microscopically, cataclasis (extension microfracturing and thermal cracking with rigid-body motions) predominates at all conditions. Dislocation gliding contributes little to the strain. Precursive extension microfractures coalesce to produce the throughgoing faults with gouge zones exhibiting possible Riedel shears. Incipient melting, particularly in wet tests, produces a distinctive texture along feldspar grain boundaries that suggests a grain-boundary-softening effect contributes to the weakening. In addition, it is demonstrated that the presence of water does not lead to more microfractures, but to a reduction in the stresses required to initiate and propagate them.

Jan 1, 1982

By R. P. Fischer

The Colorado Plateau region has been the principal domestic source of uranium, vanadium, and radium. The value of these commodities produced from the region through 1964 slightly exceeds $2 billion. Most of the deposits occur in streamlaid lenses of sandstone in the Chinle and Morrison Formations. The ore minerals below the zone of oxidation are low-valent oxides and silicates of uranium and vanadium; all of these, except the quite stable vanadium silicates, oxidize readily to a variety of high-valent uranium and vanadium minerals. The ore minerals partly replace fossil wood but mainly impregnate sandstone, typically forming tabular ore bodies that are nearly concordant to the bedding of the host rock. The deposits range in size from those containing only a few tons of ore to those containing more than 1 million tons. Stratigraphic, lithologic, and sedimentary structural factors obviously influenced the localization of these deposits, but igneous activity, hydrothermal mineralization, and tectonic structures show no similarly consistent influence on localization. The deposits are epigenetic, but the source of the ore metals, the nature of the ore-bearing solutions, and the time of ore emplacement are uncertain. A few uranium deposits in the region are dominantly discordant to bedding and occur in collapsed breccia pipes or along linear fractures. Their origins are also uncertain.

Jan 1, 1968

By H. H. Power

THE PETROLEUM DIVISION of the A.I.M.E. continued with its diversified activities during 1.935. Sessions at the New York meeting in February were devoted to production engineering, domestic and foreign oil production, and petroleum economics. The symposiums on domestic and foreign production proved their increased usefulness. The data accumulated for 1935 were added to those published during prior years in "Petroleum Development and Technology." A joint session on the use of metals in the petroleum industry was held by the Institute of Metals, Iron and Steel, and Petroleum Divisions. W. S. Farish, chairman of the board of the Standard Oil Co. (N. J.), was the principal speaker at the annual dinner. The October meeting, held in Hous¬ton, was characterized by an excellent program and large attendance. Four sessions were devoted to problems in estimating reserves, reservoir energy, properties of drilling muds, electrical logging, water flooding, and other subsurface studies. Foreign representatives of the Anglo-Persian Oil Co. presented a paper on surface tension and specific gravity of crude oil under reservoir conditions. The address by President Buehler, the dinner at San Jacinto Inn, a trip to various lo

Jan 1, 1936

By AIME AIME

THE Annual Meeting-numerically the 162d meeting-of the American Institute of Mining and Metallurgical Engineers will be held at the Pennsylvania Hotel, 7th Ave. and 33d St., New York, Feb. 18-22, with the exception of the following events: the Mineral Industry Education Division will meet Sunday afternoon and evening at the Columbia University Men's Faculty Club, 400 West 117th St.; and a meeting of the Section Delegates, the annual business meeting of the Institute, and an executive session of the Board of Directors will be held in that order Tuesday afternoon in the Engineering Societies Building, 29 West 39th St., where the Directors will meet in the evening following their annual dinner to the Section Delegates. The Pennsylvania--one of the Statler group of hotels-was selected as headquarters because it has the physical equipment and facilities-for registration, technical sessions of all sizes, luncheons, social events, etc.-as well as the prominence and location desirable for an Institute annual meeting. (A tip for Tuesday afternoon and evening: You can walk underground from the Pennsylvania to within half a block of the Engineering Societies Building,)

Jan 1, 1945

By Frederic P. Dewey

THE Bureau of the Mint of the United States Treasury maintains 13 offices for the purchase of gold-bullion, and this paper describes an investigation to establish the reasonable differences in the assay-results at the various institutions which may be commercially allowable in the settlements between them. Beginning with the comparative assay of proof-gold at the Philadelphia mint and the Utrecht mint, which shows 0.00002 as the closest agreement now possible, eight tables of comparative results, taken from the regular work of the service, are given. These tables begin with very fine gold, produced in an electrolytic refinery, showing close agreement. in the assay-results, and follow through decreasing gold fineness and . increasing amounts and complexity of base metals to very impure and complex bars produced at cyanide-mills, some of which give widely-varying results. Next is given a series of results on samples, prepared and sent out to various laboratories in the service, to test the influence of different metals and various combinations upon the' agreement of the assay-results; 11 samples were sent out and each one was assayed from 44 to 71 times, making a total of 623 assays. To these are added 107 assays of identical samples of coin-gold. On a previous occasion,' I have endeavored to show the degree of accuracy that may be expected in the ordinary everyday analysis of various materials, and on another occasion2 I

Aug 1, 1909

By Walter Renton, Ingalls

SEVERAL years ago I became interested in computing the historic lead production of the United States, and the mines, or mining districts whence derived. This led me subsequently to an examination of the recent records- of some of the American zinc-mining districts and of the great lead and zinc-mining districts in foreign countries. My present article thus will be to a large extent an addendum to my book, "World Survey of the Zinc Industry," which was published by the Mining and Metallurgical Society of America in 1931, and to which I shall refer hereinafter as Ingalls, op. cit. Throughout this article all expressions of tons mean the ton of 2000 lb. Where original data have been given in metric tons I have converted in many instances simply by multiplying by 1.1, and long tons by 1.12. I have not been fussy about digits and have rounded off many figures. These may explain differences between data herein and other data.

Jan 1, 1946

By Larry Dale

An approach for predicting the development of mineral resources on public lands has been developed as an aid to resource agencies. It consists of new techniques for evaluating the economic potential of the resource, the uncertainty about mine cost estimates, and the uncertainty about the occurrance of mineral deposits. New mineral sup- plies from inferred and hypothetical resources can be predicted by using these techniques. A case study illustrates their application in predicting development of copper resources in western Montana.

Jan 1, 1982

By H. H. Campbell

MANY attempts have been made to write a formula by which to calculate the strength of steel from its chemical composition, but most of these endeavors have failed because there were too many disturbing conditions. It is idle to collect from the pages of trade-papers, books, or the proceedings of scientific societies, a multitude of observations. The combination of such results will simply show that steel of the same composition will vary in tensile strength through wide limits-a fact that has been known for generations. That cold-working, overheating, and many another form of heat-treatment alter fundamentally the strength of steel, is ancient history, although it is only recently that the microscope has pointed out the road to an explanation of the phenomena. It may be urged that the microscopic structure must be taken into consideration in any formula giving the ultimate strength, but from the standpoint of the present investigation this is unnecessary. We are trying to determine primarily, not what changes in ultimate strength may be made by variations in the condition of carbon, but what effect is produced by changes in the amount of carbon, when its condition remains constant. For such an inquiry, in order that the condition of the carbon should remain as nearly uniform as possible, it is essential that all test-pieces be made under the same conditions; and it is be¬lieved that the tests described in this paper satisfy that require¬ment. The investigations were made at the works of the Pennsylvania Steel Company,. Steelton, Pa.; the ingots from which the tests were made were 6 in. square in every case; they were heated in the same furnace and forged at the same ham

Jan 1, 1905

By JO. E. SHERID

THE Dawson coal-mines are owned and operated by the Stag Canon Fuel Co., of which Dr. James Douglas is President and E. L. Carpenter general manager. The property is situated in Colfax county, N. M., and the openings now in operation are in townships 28 and 29 N. R. 20 E., and township 28 N. R. 21 E., shown in Fig. 1. The mines are part of the southern end of the Raton coal-field, which extends north into Colorado and embraces many coal-camps of the Trinidad section. II. GEOLOGY. Geologically, the coal-measures, commonly known as the Laranmie series of the Cretaceous system, have a thickness of about 800 ft. in the vicinity of Dawson. The coal makes an excellent coke, and, according to some authorities, its coking properties are clue to the action of intruded sheets and sills of igneous rock, the sheets occasionally thickening into masses resembling laccoliths, at such places making nearer approach to the coal and sometimes producing small areas of natural coke. There are but few dikes through¬out the entire southern portion of the field and little or no faulting along the dikes. In some parts of this great coal-field the intrusive sheets are far removed in the green shales below the coal-measures, and are so much altered as to be difficult of identification. There is but little disturbance of the strata through¬out the Raton coal-field in as far as it extends into New Mexico. There are two workable seams in the coal-measures, and two or three smaller coal-seams, ranging from 1 to 2.5 ft. in thick-

Jun 1, 1909

By M. R. HULL

FOLLOWING the discovery of a body of ore that appears to have commercial possibilities there is a period of development work to determine its extent and grade and the most economical method of mining it. Laboratory tests are made in an effort to determine the most practicable and economical treatment for the extraction of the valuable constituents of the ore and these tests are carried farther and checked in a pilot or test mill. The rate at which the ore is to be mined and the daily capacity of the plants that are to treat it will depend on a number of important factors such as: The size of the orebody; the capital available for building the plants; the market or demand for the final product; the supply of skilled and common labor available for the construction, operation and maintenance of the plants; the quantity and quality of available water, and the amount and cost of power that can be purchased or that can be economically developed. Having decided on the treatment that is to be given to the ore and after full consideration of the above factors the management decides to erect a reduction plant of a given capacity.

Jan 1, 1926