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By J. A. Botin, K. H. Singh

INTRODUCTION The Alfredo underground mine is one of the three mining operations of Rio Tinto Minera, S.A., all near the community of Rio Tinto in Huelva province of southwest Spain. The other two operations are Corta Atalaya open pit (Pyrite ore) and Cerro Colorado open pit (Copper ore 1. Underground mining of Alfredo Mine for pyrites started in the nineteenth century and continued without interruption until 1979 when it was discontinued due to economical reasons. In 1972, a new project was started for the mining of copper bearing ores on the footwall of the pyrite deposit. This copper ore is locally named “Cloritas” and it forms a nearly vertical and tabular shaped orebody which forms an envelope at the footwall of the San Dionisio pyrite orebody. Mining of the Cloritas commenced in 1975 using cut and fill stoping. In 1977, the original project was completely revised which led to the introduction of a bulk mining system to achieve a planned production of 3,000 tonnes of ore per day. This paper covers the economic and planning aspects of the mine and discusses the evolution of the mining method for the Cloritas orebody. A GENERAL DESCRIPTION OF THE CLORITAS OREBODY The “Masa San Dionisio” (figure 1 ) is a massive sulphide orebody located in the town of Rio Tinto, about 90 kilometres west of Sevilla, Spain. Extensive vein-type sulphide mineralization exists in the volcanic host rocks of the Masa San Dionisio. Within this area of stockwork veins, there is a higher concentration of copper in the form of chalcopyrite in a zone adjacent to and paralleling the contact with the massive sulphides. This copper envelope is locally referred to as the "Cloritas Orebody” and the ore within it is called "Cloritas”. The main zone of the Cloritas orebody, (figure 11, is tabular and nearly vertical having a length of 375-400 m east-west, a thickness of 20-50 m north-south, and a vertical extension of 500 m from the surface. In addition to this area, there is a second less important low grade area called zone 2A located to the north of the main zone below 26 Level which, in some sections, is not fully separated from the main zone. MINING METHODS Mining in Rio Tinto area can be traced back to the Phoenecians and the Romans. Modern day mining started with the demand for sulphuric acid during the last half of the nineteenth century. By 1971, more than 33 million tonnes of pyrite had been mined out of Alfredo Mine, (San Dionisio Orebody), using labor intensive drift and fill methods and also by open pit method. During the last decade, underground mining of the pyrite had become uneconomic due to lower prices and a slackening demand for pyrite, and the underground mining operations for pyrite were finally stopped in 1979. In 1971, a major change in the long range mining plans for Masa San Dionisio was established. Between 1971 and 1975, underground mining of pyrites was progressively reduced while open pit extraction was increased in

Jan 1, 1981

By Granville S. Borden

TAXES in general are onerous and are not a pleas- ant subject for discourse. There are, however, some very cogent reasons why we should dedicate a part of our thoughts and services to the solution of our taxation problems: The happiness of every individual in the United States depends on the maintenance of a stable government. The collection of taxes is an indispensable function of a stable government, and the power to collect taxes depends in part on the question whether taxes are fair and equitable. As representatives of the mining industry it is our duty to .protect it from tax burdens that are discriminatory or- unjust, As citizens we find that taxation is incessantly endeavouring to unravel the knots in our purse-strings. Many members of the Institute may be consulted .by clients on taxation problems, especially the phases which re- late to depletion and valuation. It is the hope of the writer that the discussion of some of the current depletion and valuation problems will stimulate interest in the problems, and as a consequence of this new interest facts will be ventilated, opinions rendered and services performed, which will be a means of solving the problems to the satisfaction of all parties interested.

Jan 1, 1929

By Kenneth R. Hancock

Iron oxides are unique in that they are the only significant colored mineral found in a natural state suitable for use as a pigment after it has been pulverized to pigmentary size. The current world production of iron oxide pig¬ments is estimated by the author to be between 450,000 and 550,000 tons based on 1969 data. The fact that highly colored natural deposits of iron ore are found throughout the world ac¬counts for its use in prehistoric man's artistic cave paintings. These early artists did not realize that they had established man's first paint test fence which now has some 20,000 years of exposure. In addition to abundance, constituting about 7 % of the earth's crust, iron oxides have the advantages of low cost, permanency, and are not toxic. Through the centuries, succeeding civilizations have utilized iron oxides as a major source for decoration and protection when coloring was desired. In the last century the chemical industry has improved on nature by developing a complete range of synthetic iron oxide pigments which surpass the pigments pro¬duced from natural iron ores in uniformity, color quality, and chemical purity. In the United States alone, the combined production of natural and synthetic iron oxides produced sales of over $28,000,000 in 1970 (Stipp, 1970). Nomenclature With the increasing importance of the syn¬thetic iron oxides it is necessary to make a distinction between the natural or mineral pig¬ments and the synthetic pigments. Natural pigments are those products which are derived from selected ores and should not be confused with iron ores mined for steel production. Iron ores that are mined for steel must be capable of being mined and reduced to iron on a com¬mercial basis. These ores are selected on the basis of iron content and processing economics. It is therefore unusual when iron ores for steel production are suitable for use as mineral pig¬ments. Natural pigment ore sources are se¬lected for their special physical-chemical prop¬erties and can command a premium price. Synthetic pigments, and in this instance iron oxides, are those pigments produced from basic chemicals. Through chemical synthesis pig¬mentary sized particles are produced as opposed to comminution, the major procedure common to all natural iron oxide pigments.

Jan 1, 1975

By Thomas T., Read

E DUCATION for the mineral industry was at first a single comprehensive curriculum, but it was early recognized that the main basis of mining is physics, while that of metallurgy is chemistry. The first school to offer curricula leading to degrees in mineral industry education in the United States (1853) had separate ones in mining and metallurgy. The Columbia School of Mines (the first really successful one) had only a single curriculum when it opened in 1864, but within a few years had so reorganized its work that it offered curricula in mining, metallurgy, geology, chemistry, and civil engineering. Interest in the metallurgy or geology curricula was slight at first, and for the next 30 years the great majority of Columbia students took the mining curriculum, probably partly because it contained nearly as much geology as the geology curriculum, practically all the metallurgy, and most of the chemistry, and partly because of the degree awarded for it. Other schools kept their mining curricula equally broad, and as late as 1900-1910 men were graduating as mining engineers who were practically as well prepared to make geology or metallurgy their life work, as they were for mining. Gradually, however, the subject matter of mining geology and metallurgy became so enriched through research and development that separate curricula in them became worth while; their progressive development is the subject of another chapter. Mining curricula also began to be somewhat diversified, and schools in areas where coal mining was of outstanding importance began to offer options in coal mining, the earlier curricula having been chiefly aimed at metal mining. The petroleum industry began its meteoric rise about the same time as mineral instruction in this country, but little more of applied science attended its birth than had attended such ancient practical arts as copper and iron

Jan 1, 1941

By W. J., Kroll

MOST people believe that rare metals are always, scarce in nature, expensive to make, and therefore useless despite some miraculous properties which might make them a cure-all. There are' some metals, which are quite frequent in nature, such as zirconium, which are called rare only because our present methods for making them are elaborate, thus forcing the manufacturer to sell them at a high price. There are also truly rare metals, such as gallium, which do not occur frequently in ores, but are easily reducible from their oxides. In these cases the price of the concentration operation is the decisive factor. The distribution of the elements in the earth's crust is no indication as to the availability of a metal; the concentration operation is the critical factor. Concentration is frequently obtained in the course of metallurgical operations for the extraction of other metals, and the rare metal may be enriched in by-products, flue dusts, mother liquors or precipitates from electrolyte purification as are indium, thallium, selenium, and tellurium. A periodic table of the rare elements may serve as a basis for discussion of their properties and to establish a program. (Table 1.)

Jan 1, 1946

By S. F. Shaw

Tars paper is a review of the principal details of cyanide practice in several of the modern plants in America, mainly during the year 1908. Two of the mills, the Goldfield Consolidated and the Vets, Colorado, are not yet prepared to give data, the former having started about Jan. 1, 1909, and the latter not yet being completed. These two mills embody most of the latest methods and are therefore described as far as possible. I. CRUSHING. The principal methods of crushing ores for treatment by the cyanide process are with gyratory and jaw-crushers, stamps, Bryan and Huntington mills, and tube-mills. The first stage is usually done by gyratory or jaw-crushers, in a few cases sup-\

Jul 1, 1909

By CHARLES R. KETES

I. INTRODUCTORY. INDUSTRIALLY, the most important service that geological science can now render to mining in the Upper Mississippi leadand zinc-fields is to devise some practical scheme whereby the productive ore-belts may be located with greater certainty than they have been in the past. Up to the present time there has been little service of this kind, and in spite of all that has been worked out concerning the geologic features of the region, and notwithstanding all that has been written about these ore-deposits, this particular phase of the subject has been, for some reason or other, the very one that has received the least consideration. The neglect by geologists in this respect has been all but complete. The following notes are suggestive of some practical solutions to the problems presented. As here suggested, the geologic relationships of the ore-bodies were surmised some years ago, though somewhat vaguely perhaps. No opportunity for securing critical data appeared until recent investigations of a private character were undertaken, which bad in view the extensive prospecting of undeveloped areas. Fresh from rather wide experiences of a decade in the principal mining-regions of four continents, and after a lenstrum's residence among the chief mining-camps of the West and of Mexico, under conditions which measured geologic hypotheses in meters and rigidly tested their values in, terms of dollars, the recent return to the Joplin field and a new survey of its ore-conditions were fraught with somewhat unexpected results. Aspects of the ore-deposition were presented of which previously there was no hint. Ten years' absence from the district had tended greatly to clarify former hazy impressions. It enabled many features, then only dimly outlined, to be considered more nearly in their true perspective and in their real relationships to their surroundings. It permitted a great mass of details collected a dozen years before in connection with the work of the Missouri Geological Survey to be viewed under new light and to

Feb 1, 1909

By W. L. Zeigler

DURING the middle 1880s, shortly after the discovery of silver-lead ores in the Coeur d'Alene district of northern Idaho, it became apparent that concentration of the ores would be necessary to obtain a profitable product. Too much siliceous material was present for direct smelting, and the majority of the ores found at depth were too low in metallic content for economic smelting processes at the time. As the ores occurred in quartzite shear zones with siderite and quartz gangue, a large quantity of waste material was present in all the mines. As the galena was not finely disseminated, this made possible relatively good extraction of the argentiferous galena by coarse concentration. The first concentrators consisted mainly of coarse crushing, screening and jigging, principally by Harz jigs, the slimes being treated on buddies. Later Wilfley tables took the place of sand jigs and vanners superseded the buddies. Because of the marketing conditions, no attempt was made until 1900 to effect a recovery on the zinc minerals present, which were found associated in varying amounts with the galena. All through this period, the greater part of the production was obtained from mines containing ore assaying high in lead and low in zinc. Parts of some ore bodies would be reversed in this respect, so that ores high in zinc were left intact. During the decade after 1910, several important mines, The Success and The Interstate Callahan, containing ores high in zinc, were put into operation and were a material aid in the needed zinc production during World War I. Gravity concentration by jigs and tables was used during this period, with bulk flotation increasing in popularity for the treatment of the fine material that had already been treated by ordinary slime concentrating machinery. No extra fine grinding for flotation concentration was thought profitable at the time. TAILINGS DISCHARGED INTO STREAMS From the start of mining and milling operations in this district until 1904, no attempt was made by the various mills in the upper district to impound or stack their tailings. They discharged them directly into the adjacent creeks or streams, to be carried away by high water. The Bunker Hill and Sullivan and the Last Chance mines, both in the relatively flat valley of the district, stacked huge piles of the coarse jig tailings on the near-by river bottom. Rain and snowfall are heavy in the Coeur d'Alene district, as it is on the heavily timbered Pacific slope of the Bitter Root Mountains. A heavy runoff occurs every spring and there is an occasional flood of disastrous proportions when warm "Chinook" winds accompanied by rain

Jan 1, 1947

By T. E. Evans, C. T. Baroch

ZrB2 was produced in batches of 4 to 6 Ib by interaction of ZrO2, B4C, B203, and carbon at around 2000°C in a simple graphite resistance furnace. Techniques of production are discussed and the final design of a suitable furnace is described in detail. Several other borides were made by the same technique and the process appears to have possibilities for commercial production. N seeking out new hard and refractory com- pounds, many researchers have turned to the investigation of the borides and excellent papers have been published on the properties of these compounds. Few papers, however, have appeared on the techniques and problems concerned with the production of these high temperature substances. This report describes progress made in developing a method for preparing zirconium diboride, ZrB2, on a pilot plant scale. The literature of the borides and other refractory hard metals recently has been reviewed, annotated, and classified so completely' that it is needless to attempt such an outline here. It is enough to say that three borides of zirconium have been reported: ZrB, ZrB2, and ZrB12.2 ZrB2 is the most stable of these and is especially stable in the presence of carbon up to and including its melting point of around 3000°C. Like most borides, it can be prepared in several ways. It can be prepared by synthesis of the elements, but these are expensive and difficult to produce in a high state of purity. Obviously, production directly from the oxides would have decided economic advantages. In electrolytic production such as that of calcium boride,:' the product is recovered as a sludge mixed with electrolyte; and separation of product from adhering electrolyte and regeneration of the electrolyte is an involved and difficult process. The work on borides was started on a small scale in 1948. Late in 1949, Naval Ordnance expressed a specific interest in ZrB2 and the project then centered on this compound. After the usual experimental work necessary in a new field, ZrB2 of good quality was produced by heating mixtures of B4C, ZrO2, B2O3, and carbon to a temperature of about 2000 °C in a resistance-type electric furnace. Over 100 lb was made for experimental use tests, and the method of production probably could be expanded into a commercial operation. A similar process has been described by Kieffer and coworkers.' The main chemical problems were the development of proper charges to insure complete reduction of the elements, determination of the proper temperature range at which these reductions took place, and adoption of techniques necessary to pre- vent inclusion of such impurities as carbon and nitrides. The mechanical problems consisted of developing a simple practical furnace that would attain the high temperatures required and permit use of a controlled atmosphere when necessary and determining of suitable refractories. Both problems were solved by designing a crucible resistance furnace. Crucible Resistance Electric Furnace Attempts were first made to produce ZrB2 in an electric arc furnace, but such a furnace would not provide the degree of carbon control required for producing clean graphite-free borides, so it was decided to try working in a crucible. Obviously, the furnace would have to be constructed of graphite, as the temperatures required are too high for other refractories or heating elements. Crucibles were made by hollowing out segments of graphite electrodes, which were fitted with a cover and clamped between two electrodes so that the current passing through the thin wall of the crucible would generate heat, using the principle of the Helberger crucible furnace."? Preliminary tests with this type of furnace were encouraging and led to the furnace design shown in Fig. 1. The essential components were a thin-walled graphite crucible resting on a graphite block, which formed the lower electrode assembly, and a top electrode assembly swung from a pipe column making contact with the top of the crucible. The space around the crucible was filled with graphite prepared from waste electrodes crushed to about ¼ in. This packing had excellent insulating properties, both electrically and thermally, and could be removed easily and quickly from around the crucible by means of an industrial vacuum cleaner. The largest resistor crucibles were machined from 8 in. electrode stock and were 26 in. long, with a side wall Yi in. thick and a 1 in. bottom. Temperatures were determined optically by sighting down a 1 in. hole drilled longitudinally through the top electrode and the crucible cover. Sealing this hole at the top was a water-cooled brass sight-glass assembly, shown in Fig. 2. An opening was provided for a light flow of helium to keep the sight opening clear of smoke, and a glass prism above the sight glass changed the line of sight to the horizontal for easier reading. More recently, the prism and optical pyrometer were replaced by a photoelectric recording pyrometer. At first the charges were placed directly in the resistor crucible but this meant that everything had to be withdrawn from the furnace every time the charge was emptied. Later, smaller crucibles were made up that could be placed inside the resistor

Jan 1, 1956

By Charles W. Perry

The options of enhanced oil recovery, coal syncrude, and shale syncrude are compared by approximately equivalent economics. The physical constraints for the major enhanced oil recovery processes are described, followed by new estimates of cost. The range for all three options in terms of light syncrude equivalent are $22 to $40 per barrel in 1980 dollars.

Jan 1, 1982

By Betty J. Laswell, Gerald W. Laswell

The stepped-up pace of US open-pit and surface mining during the 1970's is a direct response by mining firms and equipment manufacturers to rising costs and declining ore grades. In the race for bigger and more efficient machines, rotary drills have emerged as the foremost leader in primary drilling at major US surface operations. At least 12 different manufacturers now offer rotary rigs in the 102- mm-diam. (4-in.) or greater blasthole size range. With capital investment for the larger units quickly approaching $1 million, the question is asked, "What's been the performance record to date of rotary drill rigs operating in North America?" To answer that question, a comprehensive study of rotary blasthole drills was conducted which qualitatively reveals various problem areas inherent in the rotary drill market and indicates some new directions for improvement.

Jan 6, 1978

By T. Sterry Hunt

WET processes for the extraction of copper from its ores have of late attracted much attention, especially in Europe, where the use of oupriferous iron-pyrites as a' source of sulphur prevails. These processes present an additional interest, when, as is often the case, the copper-ore's to be treated contain one or both of the precious metals, since the complete separation of these from copper, either in the dry or the moist way, is, as is well known, one of the difficult problems of metallurgy. The principal wet processes hitherto in use for the extraction of copper from its ores, may be included under three classes : I. Those in which the copper in snlphuretted ores is rendered soluble in water by calcining them, after a preliminary roasting which removes the greater part of their sulphur, with a portion of common salt, by which the copper is converted into a chloride (Long-maid and Henderson), or with sulphate of soda, by which sulphate of copper is formed (Monnier). Allied to these is the method by which a portion of the copper is got as soluble sulphate by roasting without addition, a process which is sometimes modified and rendered more complete by re-roasting the lixiviated residues with the addition of a portion of raw sulphuretted ore (Bankart). II. Those methods in which free chlorhydric or sulphuric acid is used to dissolve the copper- from oxidized or roasted ores. These, while simple and efficient, are too costly, except in certain localities where chlorhydric acid is a waste product. Related to them is the plan which consists in exposing the oxidized and moistened ores to the slow action of sulphurous acid mixed with air, by which a soluble sulphate of copper is formed. It has been proposed to decompose the solutions of sulphate or chloride of copper by sulphuretted hydrogen, thus separating the copper as sulphide, and using the liberated acid to dissolve fresh portions of oxidized copper. It is, however, the almost universal practice to throw down the copper from its solutions, however obtained, in the metallic state by the use of iron, either scrap-iron or iron-sponge; although in some instances

Jan 1, 1882

By John Fritz

TROUGH it is not a condition of the Award, the fact is that the John Fritz Medal never has been given to an engineer who had not already received one or more similar awards. This "medal for medalists," on the evening of April 20, was presented to Daniel C. Jackling at a special dinner held at the Union League Club in New York. The citation read "For notable industrial achievement in initiating mass production of copper from low-grade ores through the application of engineering principles." The present award recognizes the same accomplishment-the launching and guiding to the port of marvelous success of the Utah Copper Co., first of the so-called "Porphyries"-as did the award of the William Lawrence Saunders Gold Medal by the A.I.M.E. in 1930, and before that the Award of the Gold Medal of the Mining and Metallurgical Society of America in 1926. Following the custom a biography of the Medalist had been published in a small pamphlet as a supplement to the John Fritz Medal Book. T. A. Rickard was the au¬thor of the sketch of Mr. Jackling, an innovation being the placing of a copy of the booklet at the place of each of the diners. The committee in charge of the dinner consisted of two past-presidents: R. E. Tally, of the A.I.M.E., who was chairman; Bancroft Gherardi, of the A.I.E.E.; and Thaddeus Merriman, director of the A. S. C. E., the John Fritz Medal being a joint award of the four societies. Frederick M. Becket, President of the A.I.M.E., as chairman for the occasion, briefly stated the purpose of the dinner. He stressed his satisfaction that the award was symbolic of the cooperative professional activities of the four great national organizations of engineers. He introduced Francis Lee Stuart, past-president of the A.S.C.E. and now chairman of the John Fritz Medal Board of Award. Mr. Stuart outlined the history and purpose of the Medal established in 1902 in memory of John Fritz, of Bethlehem, Pa., one of the great pioneers of America's iron and steel industry, metallurgist, and president of the A.I.M.E. in 1894. Mr. Stuart called the roll of former John Fritz Medalists, three of whom, Ralph Modjeski, J. Waldo Smith, and Ambrose Swasey, were present to do honor to Mr. Jackling. He then introduced George Otis Smith, whose privilege it was to present the Medalist for 1933. Dr. Smith was the senior of the four A.I.M.E. representatives on the Board that last year selected Mr. Jackling for the honor. His speech follows in full.

Jan 1, 1933

By T. Sterry Hunt

Jan 1, 1882

By Clinton M. Young

(Pittsburg Meeting, March, 1910.) I. INTRODUCTION. THE experiments herein. described were carried on in 1908-9 . by the State Geological Survey of Kansas. Some months before taking up work on black powder the Survey had resumed work on an interrupted investigation of explosions in coal-mines, a subject which is engaging the attention. of numerous investigators. An unusual number of serious disasters has directed to. the subject a study which discloses the disquieting fact that, in the. United States, the ratio of lives lost per ton of coal mined has been on the increase. Methods of coal-mining have changed to some extent with the great increase of output, attained in, comparatively recent years. These changes involve the working of very extensive mines, with increased difficulty of ventilation, increased accumulation of coal-dust, and. a very great increase in the amount of explosive used.. . This last point assumes truly startling proportions when it is carefully observed. In the fields of the Middle. West it is not now uncommon for a miner to use six ,kegs (150 lb.) of black powder in a "pay" of two weeks, while within the memory. of men still active, one keg (25 .lb.) would last two men for a " pay." So. great has . the use of explosives become in some fields that the skilled coal-miner is hard to find, and the coal is not mined, but blasted. A preliminary study of the subject. of explosions in coal-mines has. led to the belief . that the use of, large -quantities of explosives, in some cases by slightly-trained men, had not been * Associate Professor- of Mining Engineering, University of Kansas, Lawrence, Ran.

Aug 1, 1910

P. H. Dudley, Yew York, N. Y. (communication to the Secretary*) :—The characteristics of Professor Home's metallurgical papers are, that he is able, from the mass of confusing evidence on the subject, to make an analysis and present hypothetical and essential principles in concrete form for consideration and discussion. I can appreciate, from the practical side of the subject, the labor of collecting and investigating the data which was essential to prepare the paper. Much of it necessarily came from material of preceding years of manufacture in which time was allowed for chemical reactions of the re-carburizer, and for the elimination of the oxidation-products before teeming the ingots. This practice gave a favorable time-element to free the metal from slag and other impurities— a requisite condition for the production of sound steel in the ingots. But, in allowing them to become cold before they were charged into the furnace, a subsequent time-element entered as a detrimental factor in the development of the pipe or shrinkage-cavities, which gave an ingot-structure deficient in soundness, at least in the upper portion. (The term slag is used in a general rather than in a strictly technical sense.) Traces of manganese sulphide are often associated with manganese silicates in the same thread or seam, and at other places they are separate and distinct. Interpretations from material thus manufactured must be made with due allowances for the methods of fabrication and the requirements of service. The only way we now have to estimate what the degree of soundness of the ingot-structure was, in the early foreign and American manufacture of steel rails, is by examination of the worn and failed material after years of service. We must remember also that the poorest material was long since consigned to the scrap-heap without any full record of its history. The rails from a given ingot cannot now be identified ; and in many

Jan 1, 1909

By Donald L. Katz

THE Oklahoma City Wilcox sand, discovered on March 26, 1930, has produced 394 million barrels of crude oil and 819 billion cubic feet of natural gas as of July 1, 1941. The 100,000-bbl. wells, pressures of 2600 lb. per sq. in., and flows of "Wilcox" sand caused exciting moments in the early life of the field. Today the reservoir is substantially at atmospheric pressure and produces 75,000 bbl. of crude oil daily through 466 pumping wells. Early estimates of the initial crude-oil content of the "Wilcox" sand' indicated that about 600 million barrels of crude oil would remain after the pumping wells ceased to produce economically. The Oklahoma City Wilcox Secondary Recovery Association was organized in March 1939, to study the possibilities of recovering a portion of this oil. Only a very brief summary of the information available can be presented in a paper of this nature. Some simplification and generalizations are necessary to give the over-all picture in so short a space and statements made may not apply to a specific well or small area. Since the area under consideration by the Association is that north of the south line of section 22-11-3, some information will be presented for areas A, B, C, r, 2, 3 and part of 4 of Fig. 2, and some will be for the entire Wilcox zone west of the fault. This paper is essentially an abstract of an engineering report made by A. D. Small, B. T. Murphree, M. C. Sons and the author for the Oklahoma City. Wilcox Secondary Recovery Association on Sept. 5;.1940. Some information is taken from a report to the Association by C. V. Sidwell on March 1, 1940, and some data are from a recent report by A. D. Small. It gives a brief history of the Wilcox zone, estimates of the initial oil contents of the reservoir, present conditions in the reservoir, and probable results from several programs of "secondary recovery." HISTORY OF WILCOX ZONE The Wilcox sand lies on the flank of the general structure, as shown by cross section of Fig. 12.1 .4 and areal map of Fig. 2. The sand is of Ordivician age and is composed of well assorted, rounded' sand grains with no apparent cementing material. The loose texture of the sand is shown by the enormous quantities of sand production from the wells and from the soft cores. The productive sand varies from zero thickness on the east to 220 ft. maximum and to zero thickness on the west because of water. The development of the pool4 was dependent upon drilling restrictions within the city limits, which accounts for the spacing of drilling operations listed in Table I by years. In 1931, areas I through 7 of Fig. 2 were open for drilling with the exception of some west-edge properties, and all wells drilled before Feb. I, 1935, were in this portion of the field. Nearly all wells drilled from 1933 to 1937 were in areas A, B and C. Since 1939, the newly drilled wells have gradually enlarged the producing area toward the west in the northern portion.

Jan 1, 1941

L. C. Graton, Cambridge, Mass.—The subject of chalcocite occur; rence and its geological significance has, of course, a very important commercial bearing, as shown by the recent remark of a hard-headed mining .man: "This secondary enrichment business is one thing you geologists have put up which we can hang on to, and come out right." Most enrichments of copper ores depend upon the formation Of chalcocite from leaner sulphides. Recently it has been shown that not only does there exist this secondary or derived chalcocite, * but that in certain ores the mineral is present as an initial or original constituent, which therefore we may call primary. The desirability of distinguishing between these two kinds of chalcocite is evident and has recently been emphasized. That constitutes the first problem in this connection. I believe many who are working upon secondary enrichment of mineral deposits are giving much attention to that particular question. It is now possible to distinguish primary from secondary chalcocite in many cases. In such cases, what do we know of the' conditions under which this secondary or derived chalcocite was formed? , This is the second main question in connection with the subject. It is now plain, at least in many instances, that the formation of this derived chalcocite represents a phase of oxidation if we have in mind the primary ore as the thing acted upon. The next important question—and it is most important—is: does such oxidation go on above the zone where the rocks are saturated with water—that is, above the water level—or below, or indiscriminately above and below? Many of you have, or have had, opportunities to study at first hand, day after day, occurrences that' enable valuable conclusions to be drawn upon these and other important questions concerning the formation and significance of chalcocite. It is greatly to be hoped that your testimony will be made available and undoubtedly it will go far toward clearing up some of these doubtful points. John D. Irving, New Haven, Conn.—A short time before this meeting was called, H. V. Winchell, who was unable to be present, requested me to exhibit and describe these two samples of pyrite. (Exhibiting specimens.) They consist of fragments of pyrite inclosed in two small bottles. The first bottle shows fragments of pyrite which were immersed in water carrying copper sulphate but without SO2 for a period of two years. They remained comparatively clear and bright. No chalcocite has been deposited on them. The second bottle shows fragments of

Jan 1, 1915

By C. S. Herzig

In the Engineering and Mining Journal of Jan. 27, 1900, there appeared an article by Fred T. Greene, describing a method of measuring stopes by the use of strings, a clinometer and a tape. In the early part of 1899 I had occasion to use a somewhat similar method, for the purpose of accurately ascertaining the volume of a very irregular drift connecting two mines. This drift was an important factor in a lawsuit for $150,000, in which it was necessary to determine accurately the volume originally occupied by the material extracted from the drift. While it is unnecessary to give all details of the controversy, some explanation of the conditions is required for a clear understanding of the following description. This drift was started by the a E." Co. from its workings, in about 7 ft. of ore, and headed toward the " G " property, the plan being to extract all the ore between foot- and hanging-walls, but to take out nothing but ore. As the " G." workings were approached; the ore-body became very irregular and much thinner. It was, however, very closely followed, and where the drift broke through into the " G." workings, the hole was only 11 inches high by 14 inches wide, or just about the size of a man-hole in a boiler.. Thus, this connection-drift tapered sharply; and the very irregular foot-wall sloped toward the " G." workings, and entered them at a place where the stope was only about 3 ft. high, and the ground had already commenced to cave. It may be added that the ore-body was a nearly flat deposit of lead carbonate in limestone, the ore and gangue being quite soft. I was called upon by the " G." people to make the survey

Jan 1, 1901

By Oliver Bowles

AMONG mining men as well as in the popular mind the conviction has held sway that mining is pre-eminently a western industry. True it is that gold, silver, copper and other metals have made the States of California, Colorado, Montana, Utah. Nevada and Arizona famous. The prominence attained by these States as mineral producers is, however, not measured alone by the money value of the products of their mines. While the metals are without doubt indispensable in industry, the glamour of the precious metals, and the lure of copper, lead and zinc have given to their ore deposits a sentimental interest that often quite out-weighs their commercial importance. Today a great group of more commonplace minerals are finding a place in commerce and industry rivaling that of the metals, but there is little sentiment attached to them, and,. therefore, they attain relatively little publicity. This is the great group of the non-metallic minerals, exclusive of fuels and oils, including stone, sand and gravel, cement, lime, gypsum, asbestos, mica, phos-phate rock and many others. Almost unnoticed they have grown in production to almost unbelievable pro-portions. The estimated value of metal production for 1925 is given as $1,380,000,000, of the non-metals (ex-cluding fuels) $1,294,000,000. The non-metallic industries are not new, many of them date back almost to pre-historic times; but, as the greatest of them (on a tonnage basis) provides raw materials for the construction industries, it required the activities of the present age of construction to bring about their enormous development. Many of them enter manufacturing as well as con-struction. Non-metallic minerals constitute the back-bone of our great chemical industries. While construction and manufacture reach to all parts of the country their widest development has been in the great industrial centers of the eastern Seaboard and the middle West. Consequently the raw materials of mineral origin required for these great industries have attained a remarkable growth in the eastern half of the- United States. In compiling figures of mineral production for 1924, for which more complete data are available than for later years, the surprising fact is brought to light that the non-metallic mineral produc-tion alone of some of the eastern and middle-western States exceeds by a substantial margin the total min-eral production of some of the western States that have been classed as essentially mining States. Thus the non-metallic mineral production, exclusive of coal and petroleum, of the State of Ohio, was approximately $150,000,000; of Pennsylvania $175,000,000; and of New York $107,000,000. For the same year, 1924, the total mineral production of Utah was $84,357,000; of Montana $70,632,000; of Colorado $61,488,000; and of Nevada only $26,226,000. Even Minnesota, with its enormous iron ore production, reached only $107,845,-000, or a sum about equivalent to the non-metallic min-eral production of the State of New York.

Jan 8, 1927