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By G. Sherburne Rogers

Introduction. ONE of the features of oil-field work that puzzles operator, chemist and geologist alike, is variation in the gravity of the petroleum produced, on neighboring leases or even from adjoining wells. Few fields in the United States yield oil that is of uniform gravity throughout; in some, fields the different grades are produced from different sands, in a few from different formations, and in many from different areas in the same sand. In a few cases, perhaps, a common assumption-that the heavier oil is derived from the lighter through the escape of the more volatile constituents-is valid, but many cases can not be explained in this way. Although in the California fields the specific gravity of the oil generally decreases with depth, there are numerous exceptions to this rule; and, as in many other regions the light oil is found nearest the surface, it is evident that evaporation underground is generally an unimportant factor. It is generally recognized that the great differences between petroleum from widely separated fields are due largely to differences in age and degree of metamorphism and to variation in the composition of the original organic matter; but in the writer's opinion some of these broader differences, as well as most of the minor variations in the character of the oil from any one field, are clue to the local action of natural reagents such as sulphur or oxygen. This is particularly likely to be true if the oil has migrated from one formation to another, as in the California fields; and in some areas it appears that variation in sulphur content may even afford a rough index of the extent or distance of the migration. It is the purpose of this paper to call attention to the chemical action of sulphur and oxygen on petroleum, to show that the gravity of the oil from any one field is intimately related to its sulphur content, and to discuss the possi-

Jan 7, 1917

By D. M. S. Bhatia

The intimate association of iron formation and massive sulfide deposits has been documented by many investigators (McAllister, 1960; Hutchinson, 1972). In a classic example of such an association, four distinct facies (oxide, carbonate, silicate and sulfide) were identified in an Algoma-type iron formation occurring in Paleozoic rocks, but exhibiting physical features (banding) and chemical composition (SiO2 + A1203 + Fe2O3) typical of Precambrian iron formations. The geochemical variation of the iron formation was studied by analyzing 62 samples for Si, Al, Fe, P, S, and Cop. Following a model proposed by James (1954), the geochemical and mineralogical variation of the iron formation can be used as an excellent tool for the exploration of massive sulfide deposits.

Jan 1, 1982

By F. C. Sturges

For some time mining engineers have been interested in the possibility of using small diameter shafts, sunk by core drilling, as aids to ventilation and as emergency escapeways. The possibilities are interesting to contemplate, but new methods involve unknowns, and interest tends to remain passive until these unknowns are, solved. Recently we have completed two 36-in. diam core drilled shafts, and wish to make the data on these available to the industry. Both shafts were drilled for the McLain Fire Brick Co., one at its Buckeye mine and the other at its Colonial mine. Both mines are in the fireclay underlying the Lower Kittanning coal. Both mines have been in operation for a number of years and have required expensive maintenance work on return airways. It was decided that considerable savings could be effected by short-circuiting the air to the surface through small shafts. It was also realized that these holes, located near the present workings, would be of added value as emergency escapeways. Originally, 48-in. diam shafts were considered, but actual computations showed 36-in. diam shafts were more than ample at both mines. The shaft at the Buckeye mine is 240 ft deep, and that at the Colonial mine 258 ft deep. Both holes were started in the lower part of the Conemaugh formation and penetrated Conemaugh and Allegheny strata. The holes were started through the unconsolidated materials overlying bedrock by constructing a concrete collar with a wall thickness of 8 in. Then the shafts were drilled by the shot-core drill method. An annular groove was cut in the rock by the abrading action of chilled steel shot run under the shoe of the core barrel. The drilling was done in stages, the core barrel drilling the groove for a certain distance depending on conditions encountered, and then the cores broken off and taken out in sections. The core barrel had a 36-in. o.d. and the finished diameter of the shaft measured almost 37 in. The major questions that could not be answered until the completion of the first shaft were, (I) how much ground water would be encountered, how would it hinder the drilling, and how difficult would it be to seal off, and, (2) how would the walls of the hole stand up. The holes of course could .be cased or lined, but that is considerable added expense in any shaft.

Jan 1, 1949

By Wolfgang Pietsch

Pressure agglomeration using tableting machines, roll presses, punch presses, isostatic pressing equipment, extrusion presses, and other less common equipment, represents a large share among commercial applications of size enlargement by agglomeration. The paper attempts to classify and describe the equipment and technology, their development and state of the art, as well as their respective applications, advantages, and disadvantages.

Jan 1, 1977

University of Nevada's recent Bonanza Days celebration turned out to be the real thing when Kennecott Copper Co, presented the school with $30,000 for new laboratory equipment for the MacKay School of Mines, J. C. Kinnear, Jr., general manager of Kennecott's Nevada Div., handed the check to Stout, university president, Chemical Construction Inter-American Ltd,, signed a contract with Noranda Mines, Ltd. for construction of a sulphur-iron plant in the Niagara Peninsula. Work has been started and it is expected that the plant will be finished by summer 1954.

Jan 6, 1953

INTRODUCTION The geology of porphyry copper deposits in the southern Cordilleran orogen is the subject of this chapter. The area considered extends northwest from southern Mexico to the Columbia volcanic plateau, the Cascade volcanic province, and the Idaho batholith. Transversely it is a belt some 800 km (500 miles) in width bounded on the west by the Sierra Nevada range. Included within this area are many large segments considered unfavorable for hosting porphyry copper deposits, which are mentioned in the text. The region and its porphyry copper deposits have probably been more intensely studied and reported in the literature than any other area in the world. This summary considers regional geologic controls that governed formation of porphyry copper deposits within this province. Geologic factors that influenced the mineralogy and metallogeny of the deposits are also examined. Discussions with H. R. Cornwall have greatly helped in writing this section. GEOLOGIC SETTING The geologic setting has been summarized by Anderson (1966), Burchfiel and Davis (1972), Rogers, et al. (1974), and Lowell (1974). No porphyry copper deposits in this area are known to be pre-Triassic, so Mesozoic and Tertiary events will be stressed. Figs. 40 and 41 show basic data believed most pertinent to the topic of porphyry copper deposits. Pre-Middle Jurassic: Figs. 40 and 41 contain the principal structural and crustal ele¬ments found in the Cordilleran orogen after Anderson (1966), Schmitt (1966), Coney (1972), Rogers, et al. (1974), and Lowell (1974, 1976), together with location of some of the more important porphyry copper deposits. The western limit of the Precambrian craton is shown in Fig. 40 (Rogers, et al., 1974). East of that limit the crustal environment through which the porphyry copper plutons ascended includes the Precambrian basement as well as varying thicknesses of Paleozoic shelf and platform accumulations. The northwestern and western portion of the southern Cordilleran orogen west of the Rogers, et al. (1974) limit of Precambrian basement has what Churkin (1974) calls a thin continental crust. Brooks (1976) and Churkin (1974) describe oceanic volcanic

Jan 1, 1978

By H. M. Bannerman

IN the past few years the mineral raw materials problem has risen from comparatively obscurity to great national significance. The transition has come so rapidly that the nature of the problem and what it portends have not yet been clearly defined. Consequently there are wide differences of opinion among the experts as to what can, or should be done to insure a continuing, adequate supply. On one hand, it is said that depletion of known domestic deposits and lagging discovery of new ones will bring about an imminent decline in mineral production and that in future U. S. mineral-using industries will have to depend on foreign sources for more and more of the major mineral raw materials. On the other hand, it is argued that domestic mineral resources are virtually inexhaustible if there were only legislation against competition from low-cost foreign producers. Still another school of thought contends that within the past decade the country has entered a period of unprecedented mineral discovery that is rapidly solving the problem of depletion. Only time will tell which of these widely divergent views is nearer the truth, for mineral resources are, after all, the result of research and adaptation, and resources of the future, as of the past, will depend largely on human response to circumstances. Of 18 substances now termed reactive metals, only 8 (boron, thorium, potassium, sodium, lithium, uranium, molybdenum, and tungsten) were considered of commercial significance at the turn of the century. Except for hafnium and rhenium, the other ten were well known to chemists and mineralogists before this, but none had found use commercially, whereas some, like titanium, were looked upon as nuisances in the ores of other metals. Of these ten elements, several were considered of minor commercial significance, and others were of little more than academic interest as recently as 15 years ago. Before World War II only a few of the better informed spoke of uranium or thorium as possible sources of power. Still fewer talked of converting boron into a super- fuel, and the time had not yet arrived when hafnium, rhenium and even zirconium were thought of as critical to U. S. welfare and safety.

Jan 10, 1957

By Henry Hibbard

THE process of making washed metal now followed is in principle that described by Holley before this Institute in 1879, as the Krupp washing process. Sir Lowthian Bell also experimented extensively in England during 1877 and 1878 on refining iron and joined his interest with Krupp, the process being often referred to as the Bell-Krupp process. The only plant in this country now operating this process is that of the Brier Hill Steel Co., Youngstown, Ohio. This process may be considered as the sole survivor of the numerous methods conceived for refining crude iron, when the removal of phosphorus from steel-making material was the great desideratum affecting large districts. The east coast of England and all northern Germany, the homes of Bell and Krupp, respectively, could at that time make steel only from imported ores. These processes were in use or in various stages of development 40 years ago and all except the Bell-Krupp received their quietus from the development of the basic steel processes, both pneumatic and open hearth. The aim of the early refining processes was, first, the removal of the silicon; which could be clone on a sand bottom, and later, the removal of the phosphorus, requiring a bottom which would give or permit a basic slag. The incidental advantages of increased yield and small fuel consumption were not generally recognized or considered; the aim of the later. operations was the saving of the difference in value between low and high phosphorus irons, as well as hastening the removal of the metalloids. The chemistry of the washing process follows in part that of the puddling process, and indeed washing might, be considered as the first half of puddling, since all the non-ferrous elements of the crude iron, except the carbon, are eliminated and the iron is maintained molten until cast. In puddling, the iron loses its carbon as well, and because of that, its fusion point rises above the hearth temperature; it freezes into a pasty malleable form, and is worked at once by squeezer, hammer, or rolls.

Jan 12, 1915

By Shiou-Chuan Sun

THE effects of oxidation on the flotation behavior of sulphide minerals have been extensively studied,1-3 but no similar study has been made of coals. Coals of bituminous and lower rank undergo atmospheric oxidation during mining and storage, and their degree of oxidizing increases with temperature4,5 and time of exposure.6 The problem of recovering fine oxidized coal from culm piles, rivers, and streams by froth flotation has become increasingly important to the coal industry as well as to those concerned with air and stream pollution. This paper describes the flotation behavior of oxidized and unoxidized coals and carbons in the presence of oily collectors and presents the reagents found effective in the flotation of oxidized coals and carbons. Except where otherwise stated, flotation tests were performed in a 50-g Denver flotation cell. Solid feed for each test was 30 g, and the pulp dilution was kept at 8.5. The -65 mesh coal sample was wetted by agitation with water in the flotation cell for 6 min, then conditioned with a predetermined amount of collector for 2 min, and finally floated with pine oil as frother for 3 min.

Jan 4, 1954

Melbourne, capital of sedate Victoria, is oddly enough the home of a game known as "Australian Rules." Euphemistically described by devotees of the game as a cross between Rugby and Soccer, it appears to the novice to be more akin to organized mayhem. They don't even play it in some parts of Australia, but in Melbourne 60,000 to 80,000 whooping spectators throng the Cricket club of a Saturday afternoon to see a match. Actually, the game is fast and grueling but the victory laurels always go to the skillful team, the one that plays the ball rather than the man. Australians also play the ball in their ground rules affecting those interested in mineral exploration and mining. Prospecting Rights: Throughout the island continent, nearly all mineral rights are reserved to the Crown, administered by the individual states and, in the case of the territories by the Commonwealth government. The owner of the surface rights cannot sit on his minerals, and the term minerals even includes sand and gravel. Prospectors are protected by mining codes or ordinances of the various governments, which are quite similar from state to state.

Jan 10, 1964

By Paul K. Krueger

SUMMARY Since 1970 the Federal Preparedness Agency has been using computer models to help establish the amounts of strategic and critical materials to be held in the National Stockpile. Fifty-three of these materials are metals or minerals. The following diagram shows the linkage of models used to estimate material requirements. [ ] The starting point for the models are estimates of the major components of GNP for some future period. These may be estimates purchased from a forecasting service or may be produced in-house. The projections are translated into industrial final demands using DITT (Demand Impact Transformation Tables), a system developed at FPA. Then using a version of the current Bureau of Economic Analysis input-output model, estimates are made of the gross output of each industry necessary to support the level and composition of GNP as specified by the macro-economic model.

Jan 1, 1977

By Robert B. Hill

A history of gravity classification shows the development of many types of equipment with several prominent types continuing in use today. Part of the development and evolution is the spiral classifier. Data will be presented showing characteristic size separations in a closed circuit grinding operation. Comparisons with hydro- cyclone operation will be shown including operating cost comparisons. Effects of variables will be shown in spiral classifier operation. Finally, other uses for spiral classifiers will be described.

Jan 1, 1982

By Paul H. Lu, Fred D. Wright

Numerous laboratory tests and field measurements conducted by different persons have indicated that most mine rocks behave viscoelastically rather than elastically. Hence, for an accurate and realistic design of underground structure, the time factor should be taken into account, and the theory of viscoelasticity can be used. By considering the time factor, the time-safe-strength may be used for economical design instead of liberal safety factors with design based on the elasticity theory. The deflection and moment distributions on an elastic roof slab resting on elastic pillars have already been studied.l In this chapter, the stress- strain analysis for a viscoelastic mine roof resting on pillars of the same material or on supports of different material is first considered theoretically. Viscoelastic solutions for deflections, moments, and shears are de- rived from the elastic plate theory on the basis of the elastic-viscoelastic correspondence principle. The Laplace transformation technique is employed as the operational method in the mathematical treatment. The roof slab materials are represented by four different rheological models and four different loading histories are considered. The method of finite difference equations is employed for solving the partial differential equations, using FORTRAN programs to calculate roof deflections, moments, and shears. Numerical examples are given for one of the four models under two of the four loading histories with regular and staggered pillar patterns. The results are discussed in terms of the variance with time of deflections, moments, and shears as well as their variation in space due to the dimensions and configuration of the structure system. A viscoelastic slab resting on viscoelastic pillars or on elastic supports

Jan 1, 1972

By E. Gybbon Spilsbury

The recovery of gold and silver from their ores by means of the cyanide process has been so successful in the last few years that ally radical improvement would seem impossible; yet the appliance to which I wish to call attention in this paper is really a radical departure from the methods now in general use. The most modern and approved of these, known as the all-slimillg method, depends for its success on the grinding of the ore so fine that practically 90 per cent. of it will pass through a 200-mesh screen. The slimes thus produced are then agitated and aerated in tanks of various types. The main object of this treatment is to insure such a thor-

Jan 1, 1911

By J. F. Kemp

IN submitting an additional contribution to the discussion on ore-deposits in the recent volumes of the Transactions, it is my desire to adhere closely to matters of material importance as affecting the actual processes. Judging from the discussion by Professor Van Hise, and from one or two reviews or other articles by associates of his in geological work, the impression seems to prevail that, in so far as my paper* referred to ,his masterly essay,†I was guilty of misconceptions regarding both the part attributed by him in it to the igneous rocks and the ubiquitous presence of the ground-water. I should regret extremely to be wanting in these particulars or to have misunderstood one for whose great services in this and other branches of geology no one has a higher esteem than myself. I have, however, in the most careful way, and with these points in mind, read his essay again, anti, taking it as a whole, I cannot gain any different impression of relative magnitudes than the one first received. The importance of the igneous phenomena and the restrictive influence of the processes described by " cementation " in their effect upon the ground-water, as set forth in Professor Van Hise's " Discussion " (Trans., xxxi., 292), impress me as being in very marked contrast with the same things in his first essay. If the point seems to anyone of sufficient importance, it can easily be decided by reading the originals. My paper was the result of some years of observation, reading and reflection, and was meant to be an independent contribution, controversial only in some subordinate particulars. In depicting the drama of the deposition of ores, I cannot but feel that Professor Van Rise assigned to the chorus and the scene-shifters some characters which, it seems to me, should

Jan 1, 1913

By Zay Jeffries

THE object of the present paper is to enlarge somewhat on the general principles advanced in my discussion 1 of Mathewson and Phillips' article on. The Recrystallization of Cold-Worked Alpha Brass on Annealing.2 It will also serve as an acknowledgment of Prof. Howe's3 most important remarks on my contribution. In this paper the writer has adopted Prof. Howe's suggestion to substitute the term "germinative temperature" for "critical temperature for grain growth." Instead of being an exact or certain temperature it should be considered that the germinative temperature phenomenon exists throughout a small temperature range. Factors Influencing Fast Growth Phenomena The development of grains of macroscopic size at the germinative temperature should be considered the extreme condition of a general rule. When considered in this light it is not strange that the development of these large grains should be the exception and not the rule. The principal factors influencing the operation of the laws of fast growth temperature are as follows: 1. Rate of heating.

Jan 10, 1916

By Ernest A. Hersam

The advantages of the tri-axial diagram in representing the composition of slags and silicates are well appreciated by many metallurgists. Prof. H. M. Howe* has pointed out the application of a fourth variable, in connection with the diagram, and has called attention to the usefulness of the general systern of tri-axial representation. In the discussion of Prof. Howe's paper, Mr. Firmstone† indicated how certain distances could be measured directly by projection. Prof. R. H. Thurston,‡ as early as 1877, had made use of a typtic model and of triangular diagrams, with contour-lines, rekrresenting varying physical properties corresponding to varying chemical composition. Still earlier, Prof. J. Willard Gibbs§ had used the diagram in similar work; and other scientists were thought by him to have preceded him in its use. During the period of nearly a quarter-century, following these early publications, there has been an ever-increasing use of graphic methods in numerous branches of scientific work, stimulated, in part, by the possibility of representation by three co-ordinates upon plane-surfaces. Yet the number of possible co-ordinates for graphic representation has always been, and always must be, insufficient to express many facts which are shown mathematically; while, without graphic representation, the involved nature of mathematical expression often fails to facilitate and promote research. The coming into use, therefore, of the fourth co-ordinate, permitting representation by four variables, marks but the beginning of some lines of research which could not well advance without this aid.

Jan 1, 1902

By T. M. Daulton, Chester F. Lee

The Atlin Mining District is in the northwest corner of the Province of British Columbia. Ruby Creek, where the operation to be described is situated, is 17 miles east of the town of Atlin and about 18 miles south of the south line of Yukon Territory (Fig. 1). Gold was discovered in the district in January, 1898, and the production to date from placer mines has been $4,518,000, according to the reports of the Minister of Mines for the province. Geology The essential points in the regional geology are given in the following paragraphs. Long erosion produced a plane-like surface slightly above sea level with a few peaks and ridges.' A gradual uplift followed and erosion increased, the streams cut deeper, the cuts so made being afterward increased by glaciation. The ice straightened and planed the slopes of the main valleys and widened and lowered their floors, in some cases flooring the valleys with silt, sand, gravel, and clay. As the glaciers rapidly retreated, lakes were formed. As to the origin of the gold, J. C. Gwillim says? "The Surprise granite has been carried northward toward Gladys Lake and Teslin, and the granite of the great plateau on the Taku trail was found in blocks on the opposite range across Hurricane River 10 miles north of its original position. Otherwise there is little evidence of far removed material, the boulders of the lake shore and creek beds being of local appearance. This appears to strengthen the opinion that the placer gold had its origin within the drainage basins where it is now found." In the gold-bearing creeks of the Atlin district there are two "runs"

Jan 1, 1917

By H. D. Hoskold

As the theory and the practice of valuing mines have never been discussed in the Transactions, a paper on the subject may be acceptable, even though not exhaustive. The method here indicated is set forth, not as a model of perfection to be followed absolutely, to the exclusion of any other system based on sound scientific, commercial and equitable principles, but merely as an aid to mining engineers and financiers in estimating the value of mining-property. This paper is intended merely to point out certain financial features of the question, and not at all to go into the theories of the formation of mineral veins, extremely valuable as it must, of course, be to understand the laws of the earth's formation and of its various changes, which are the basis of such important sciences as geology and mineralogy, and highly useful as guides in determining the probable existence and extension of mineral deposits. Financial Elements of Mine- Valuation. The practice of basing the stock-exchange price of mining shares upon reports, periodically received from the mine-captain or manager, stating that in his opinion the mine is " improving " in this or that level, and is worth so much " per fathom," is, of course, absurd. Everybody experienced in metalliferous mining is aware that a mineral vein varies in thickness and also in percentage of metal in different parts of the same mine. According to the practice just indicated, a mine must have had as many values a per fathom " as there have been given reports upon it at intervals during the year,

Jan 1, 1903

By A. T. Beckwith

The Lehigh Navigation Coal Company Inc. operates steep-pitch, relatively deep mines in the Panther Creek Valley, at the eastern end of the southern anthracite coal field. Commercially minable coal beds are the Mammoth,† Primrose, Orchard, and Buck Mountain;‡ their respective thicknesses average 50, 15, 10 and 12 ft. Sand slates immediately overlie and underlie these beds, though in some locations sandstone or conglomerate beds occur. Underground operations extend to a depth of 1200 ft. below the surface, and comprise a bulk of virgin work on the lower levels, and a small amount of remining on the upper levels. With increase in depth, ventilation has become a more important factor. Development In early days slopes or drifts were driven in the outcropping coal on the hillsides. Subsequent development was by water-level tunnels, with portals above high water in Panther Creek. These tunnels have been maintained because they intercept and drain much water that enters the mined-out portion of the bed and otherwise would follow down to the deep workings+ Below these tunnels, the coal was customarily developed by slopes. Muleways, which are zigzag chutes easy to travel, were also driven to connect lower openings with the water levels. When it became necessary to go still deeper, the slopes were abandoned, and vertical multicompartment shafts were sunk from the surface. Levels have been at vertical intervals of from 175 to 250 ft. Recent practice has been toward the latter spacing, splitting the total lift, however, by starting to mine from chutes extending halfway up to the level above. Chutes customarily are spaced at 50, 60 or 70-ft. centers along the gangways. At some mines, additional shafts have been sunk from the surface to the level containing the main pumping station, and these carry the discharge lines from the pumps. As the mines are ventilated by the exhausting system, both the hoisting and so-called water shafts serve as intakes. The main fan is always on the surface, and is connected with the return airways from the various levels by an air hole or a vertical shaft. For economy, when the present deepest levels were developed, and return-air shafts or air holes were not extended to the new level, but connections were made from the new level to that above by two or more holes. It is doubtful that this method will be continued, as complications in the system, increased resistance to flow, and other difficulties undoubtedly will counterbalance any economies this provision may afford. During the early years of mining, when operations were at no great depth, all development headings were driven in the coal bed. As mining progressed downward, increased ground pressures slowed develop

Jan 1, 1942