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By Donald N. Rosenblatt

I would like to commend the author on his description of Pinto Valley's plant, and its interesting innovations. The author's discussion of 18 ft in diameter by 21 ft long primary ball mills (the largest wet ball mills made to date) is of considerable importance to those who have been engaged in the field of studying ball mill liner wear as it relates to various grinding installations. While it is stated that the mills have operated on a fixed tonnage and therefore it has been difficult to determine the best liner pattern, calculations from the data in the paper indicates that for mills 1, 2, 5, and 6, the tonnage per hour varies from a low of 223 for mill No. 1, up to a high of 314, for mill No. 2, while mills 5 and 6 calculate 285 and 246, respectively. Analysis of the wear patterns for the single wave liners used in mill No. 1 as compared to the double wave liners in mill No. 2, suggests that the author's data may tell more than he suspects about liner wear to be expected and thus what should be a best pattern selection from what may appear to be only limited hours of operation. [Fig. A] is a reproduction of author's [Fig. 10], to which wear forecast patterns [F-1 and F-2] have been added. Forecasts are based on many previous studies of large diameter ball mill operations over many years of field service. Calculations from the first-wear pattern provide an initial wear rate of only 13 lb of liner per 100 sq ft of shell liner surface per day, or 0.031 lb per to: ground. However, the second wear pattern is ac-

Jan 1, 1978

By A. L. Field

Bureau of Mines Technical Paper 189 consists of a record of the scientific data obtained in the iron blast-furnace slag investigation which is reported in Technical Paper 187, "Slag Viscosity Tables for Blast-Furnace Work." It includes a description of the method of preparing the synthetic melts, construction of an improved electric furnace, and refinements in laboratory methods of measurement. Only the general features of the work and the conclusions drawn from the experimental data can be given attention here. Silicates in the Liquid State In the manufacture of refractories, Portland cement, glass, and porcelain, and in pyrometallurgical operations, importance attaches to the behavior of silicate compounds at temperatures beyond the range of common experience. This field of research has not been investigated as carefully as its scientific and industrial importance would seem to warrant. Probably the most important of the unsolved problems in the, chemistry of silicates is the question of their stability in the liquid state. That little progress toward the solution of this problem has been made is not strange if there be borne in mind the difficulties attending experiments made at temperatures at which silicates become fluid, and the comparatively short time since it became possible to measure these temperatures. On the other hand, considerable progress has been made in the study of the compounds in the solid state because of the directness and simplicity of methods of optical examination.

Jan 12, 1917

By Thomas Watson

Introduction THE occurrence of zircon in pegmatites of acidic composition is recorded by many observers both in this country and abroad, and they form one of the most important geologic modes of occurrence of the mineral.' As is well known, commercially the most important American locality for zircon is near Zirconia in Henderson County, North Carolina, where many tons of the mineral have been obtained from a kaolinized pegmatite dike 100 ft. wide and traced for 1 ½ miles along the direction of strike N. 50° E. Zircon may be developed in pegmatites as inclusions in the principal rock-forming minerals, chiefly quartz and feldspar, and as a separate megascopic constituent in the form of grains and crystals not exceeding, as a rule, 2 in. in size, and usually smaller. In the Henderson County, North Carolina, pegmatite, zircon occurs in prismatic crystals with pyramidal terminations measuring up to 30 mm. in diameter, associated chiefly with the feldspar. In some of the apatite veins of Canada, which are closely allied to pegmatite dikes, zircon is reported in crystals upward of 6 in. in length and 2 in. 'and more in thickness. Zircon in large masses occurs in Virginia in the well-known pegmatites near Amelia in Amelia County, and near Gouldin in Hanover County. Both localities are in the middle eastern portion of the Piedmont Plateau province, and are separated by a distance of about 40 miles in a northeast-southwest direction. The rocks of both areas, including the pegmatite bodies, are in an advanced stage of decay, and, the hard and moderately fresh rocks are concealed beneath a cover of variable thickness of rock decay derived by the normal processes of weathering. Exposures, there-

Jan 7, 1916

By R. Stanford

In any discussion of steel pouring too often refractories quality assumes a high level of importance. Unfortunately when one considers the many and varied conditions to which pouring refractories are exposed, it is difficult to isolate the true role of refractories quality alone. Some of the more important, yet often overlooked, variable conditions bearing on pouring performance are heat size, tap time and temperature, steel chemistry, ladle additions, ladle height and preheat, mechanical conditions of the pouring mechanism, hot top or non hot topped ingots and, ingot size, which determine total number of shutoffs, direct or tundish pouring, ingot filling rates, metallurgical demands, etc, etc. These considerations apply for either conventional or slide gate pouring of ingots and, to a large extent, even strand casting. In any event probably the most significant factor on pouring performance in any individual shop is what is considered an "OK" pour. We find considerable variance in this qualification, not only between Republic Steel meltshops, but throughout the industry. Therefore, it is a worthless exercise to draw comparisons attributable to refractories quality alone, except for similar conditions in a single shop.

Jan 1, 1972

By David J. Dunn, Richard G. Martin

Of many physical parameters critical to design of grinding processes, impact of grinding media is among the most difficult to measure or predict. Yet impact of falling grinding balls, pebbles, or rods accomplishes the fine grinding essential to metallurgical recovery of most important minerals. Unfortunately, the same impacts that break ore fragments deform or crack grinding mill liners. A project was undertaken at Climax Molybdenum Company to measure impact forces in operating ball mills so that they might be used to calculate stresses in liner materials and be correlated with service performance of mill liner alloys. Towards that end, a method of measuring impact forces on ball mill liners using an instrumented grinding ball has been developed. Preliminary tests show that impact forces and contact stresses imposed on bare mill liners are quite high but are greatly reduced by cushioning when coarse ore particles are crushed between balls and liners. Compressive and shear stresses induced in liners not protected by coarse ore are so severe that deformation or minute subsurface cracking are inevitable in all but the small production grinding mills, regardless of mill liner alloy strength or hardness.

Jan 1, 1979

By J. V. Emmons

THE processes of hardening and tempering steel tools within the past 15 or 20 years have been so developed that the forward strides of the industry can scarcely be followed by the average observer. No small part of the credit for this phenomenal advancement is due to the improved methods of measuring the high temperatures necessary. Pyrometry has made possible the discovery and use of the many special alloy steels the wonderful properties of which are revolutionizing the industrial world. So sensitive are these steels to changes of temperature that often a variation of only 10° F. at a critical point of the heat treatment will cause the failure of the tool. In the tool-manufacturing industry today, accurate control of the many heating operations is imperative. The principal processes in the manufacture of tools that require accurate high-temperature measurements are annealing, carburizing, hardening, tempering, and laboratory research. Several other operations, such as forging and straightening, use rougher and correspondingly less accurate methods. These operations are usually performed in the following approximate ranges of temperature: DEGREES F. DEGREES F. Annealing 1000 to 1700 Tempering 200 to 1200 Carburizing 1400 to 1000 Forging 1400 to 1800 Hardening 1400 to 2500 Straightening 300 to 1300 Laboratory research covers the entire range. Annealing and carburizing are usually done in muffle or semi-muffle furnaces, heated with coal, coke, oil, gas, or electricity. Many of them are of large size, holding several tons of steel at one charge. Both indicating and recording pyrometers are used. The recording instruments are generally of the thermoelectric type, while for the indicating, both optical and thermoelectric are used.

Jan 9, 1919

By George A. Komadina

The Pima mine lies 20 miles southwest of Tucson, Ariz., and 45 miles north of the Mexican border. It is located on a hillside overlooking Tucson, which allows for gravity flow generally through the plant. In April 1965, an expansion was authorized by the mine's board of directors. This will triple the mine's output to 18,000 tpd. At this rate, it is estimated that there is sufficient ore to last 20 years.

Jan 6, 1965

By R. F. Sheldon

Largest uranium deposit in the Northwest is Dawn Mining Co.'s Midnite mine on the Spokane Indian Reservation. The orebodies lie along the contact of granite and metamorphosed sedimentary rock and are controlled by faults and shear zones near the granite contact. In the oxidized zone the deposits consist mainly of the secondary uranium mineral meta-autunite; sooty uraninite and primary uranium minerals are known to occur at greater depths. Elevations in the mine area range from 2500 to 3500 ft. The rolling hills and low, rounded mountains are covered with grass and evergreen trees. HISTORY AND DEVELOPMENT Original showings were discovered with a geiger counter in the spring of 1954 by prospectors Jim and John LeBret. High radioactivity in several schist outcrops was found due to scaly coatings of a greenish-yellow, fluorescent mineral, later identified as meta-autunite. Prior to this time autunite was not known to occur in the state of Washington, and no significant uranium deposits had been found in the Pacific Northwest. Outcrops in the area were few, and most of the ground was mantled with 2 to 10 ft of overburden, but three other radioactive zones were discovered by prospecting the ridge southward along the strike of the schist near its contact with granite for three quarters of a mile. Midnite Mines Inc. was formed

Jan 1, 1960

By William White

History.—The making of iron and steel from the ores of northern Mexico was for years a favorite project of the late Don Patricio Milmo, upon whose estate large deposits of coal and iron were known to exist, and with whom Mr. Eugene Kelly, of New York, was associated. Several expert examinations of the property mere made for them; and when failing health forced Sr. Milmo to retire from active part in the matter, Mr. Kelly carried on the project and associated himself with Messrs. Vicente Ferrara, of Monterrey, Antonio Basagoiti and Leon Signoret, of the City of Mexico, and other leading citizens of Mexico, Monterrey and New York, who, in May, 1900, organized the " Compania Fundidora de Fierro y Acero de Monterrey," with a capital of $10,000,000. The main reason for locating the plant at Monterrey was, that a circle drawn with Monterrey as a center, and the distance from Monterrey to Laredo as a radius, will contain all the known Deposits of iron-ore of Bessemer quality, and the greater part of the available coal, in the Republic. Moreover, Monterrey is connected with all the Mexican trunk railwaylines, and thus with the Gulf of Mexico, and supplies, therefore, the conditions necessary for prosperous manufacturing, namely, cheapness in assembling raw materials and means for wide distribution of product. It also has a number of enterprising citizens, who have been successful in mining, smelting and manufacturing operations, and a sufficiently large population to supply the necessary labor. Iron-Ore.—The company's iron-mines are on the Carrizal mountain, on the Mexican National, and at Monclova, on the Mexican International railroad. At the former locality, two mines, Piedra Iman and the Anillo de Hierro, sufficiently large

Jan 1, 1902

By William Daly

THE application of artificial refrigeration, or air-conditioning, to the ventilation of deep, hot mines has long been a subject of interest to the operators of such properties. Artificial cooling of the air in theaters, railroad coaches, and various industrial plants has been so successful within recent years that it has been natural to assume that the adoption of similar methods would afford a ready solution to the difficult problem of mine ventilation. It should however, be obvious, that although there may be nothing technically impossible in the application of this process to mine ventilation there is a great economic distinction between the maintenance of a high standard of comfort for a large number of people in a relatively small space such as a theater and the cooling of air to improve working conditions for miners scattered throughout the extensive workings of a large mine. Many methods of air-conditioning have been considered by the management of the Anaconda Copper Mining Co. at various times, but until the development of the process to be described in this paper none has seemed economically practicable.

Jan 1, 1934

By William Kelly

I AM-glad to have the opportunity at this time to say that I consider it a very great honor to be elected President of the American Institute of Mining and Metallurgical Engineers. It fulfills the proudest hopes of my ambition. There is, ,however, one drawback to my personal gratification-a feeling of unworthiness to have my name placed on the list with former Presidents of the Institute, with the brilliant Raymond who guided our society for so many years, with the versatile and lovable James Douglas, my first employer and my friend, a most generous benefactor of our Institute, with the skilful Holley, who gave to the manufacture of steel in this country, its first great impulse, to mention only three of the accomplished men who have preceded me. I assume that the honor of my being elected President of the Institute is not merely a personal one but that it should be considered a tribute to the wonderful progress in the art of mining, both underground and in open pits, and in the beneficiation of native copper and iron ores, which have been shown in the Lake Superior District and also a recognition of our members there and elsewhere who are living at the mines and directing the operations, upon the success of which the whole mineral industry depends.

Jan 1, 1924

By C. S. Barrett

Measurements of impact hardness of ß-brass are reported for a wide range of temperatures. Abrupt softening is observed when temperatures are raised above 425ºC, accompanied by abrupt widening of deformation bands in the deformed samples. Current theories of these effects, and of the lack of twinning, are discussed. HARDNESS1 and flow stress2 of a sample of ß-brass at room temperature depend upon the temperature from which the sample is quenched. It is believed that the state of order in the superlattice is responsible for this dependence—not the order within individual domains, which reaches near-perfection during the quench from any temperature, but the size of the domains which is presumed to be a minimum in the hardest samples, those quenched from temperatures near the critical disordering temperature of 468°C. Measurements of impact hardness made over a range of temperatures and microstructural studies of samples deformed both rapidly and slowly over a range of temperatures, reported herein, should be of aid in reaching a more complete understanding of the underlying factors controlling the properties of the disordered body-centered-cubic material and the ordered material. It appears that such data have not

Jan 1, 1955

By Charles Mitke

EXCLUDING top-slicing, and sublevel caving, large production caving methods may be divided into two general classes, the branch raise, or undercut caving method, and the combined shrinkage and caving method, each of which has a number of variations, the result of continual efforts towards obtaining lower costs and better extraction, by the introduction and substitution of minor improvements and modifications. EARLY CAVING METHODS Present caving methods are the cumulative result of developments covering a period of many years, with the most rapid growth during the past 15 years. They originated, presumably, from early English stoping methods, and, as far as is generally known, were first introduced in the Michigan iron district. They have had their greatest expansion and application in the large low-grade porphyry coppers. In their present form, they are probably a development and combination of sublevel caving and shrinkage (back-stoping on ore) with gravity handling of broken material. Sublevel caving, as practiced in the Michigan district today, is a combination of drift, or crosscut, mining, with top-slicing, and caving, supplemented by later refinements in the shape of mechanized handling of broken ore. A height of anywhere from 16 to 20 ft. is generally taken, and the ore is drilled and blasted along the drift or crosscut for half this height (say 8 to 10 ft.), after which the upper 8 to 10 ft. caves and breaks of its own weight, with comparatively little assistance from drilling. This

Jan 1, 1928

By C. M. Boss

Throughout the Lake Superior Basin each of the great ironranges, from which vast quantities of iron-ore have been, and are now being mined, presents characteristics differing from each and all of the others. One of the most peculiar of these varying features is found in the dikes of the Gogebic range. From an economical standpoint this feature of the dikes has been studied by our practical mining men more than any other geological phenomena in connection with the deposits of merchantable iron-ore. In the greater portion of our mines these dikes appear to form the riffles in the sluice of the ore formation, against which the particles of iron oxide are deposited in the process of concentration out of the quartzose matrix which is termed the ironbearing formation. In composition these dikes are apparently of a dioritic formation, more or less altered and decomposed, comparatively soft, and sometimes almost steatitic. While frequently showing something of a cleavage in the direction of their pitch, they are devoid of parallel laminæ, and when broken assume the form of irregular angular fragments. They are generally of nil ashy grey color, but sometimes at great depth are found to be quite dark, almost black, and of a very hard massive nature, showing radial or fibrous crystallization. Practically all of the dikes thus far discovered in the iron formation are approximately at right-angles with the dip of the formation, and the greater number of them have an average easterly dip of from fifteen to eighteen degrees. Sometimes, however, they are folded in such a manner as to form long synclinal basins; but while their western or initial extremity is fre-

Jan 1, 1898

By Charles A. Anderson

THE Bagdad copper deposit is of the disseminated type (porphyry copper) occurring in a quartz monzonite stock of late Cretaceous or early Tertiary age. This stock, located essentially at the intersection of two dike swarms, is the only one of several stocks cropping out in the area which is appreciably fractured and mineralized. Most of the rocks in the area are of pre-Cambrian age, but their structures have had no discernible influence on the copper mineralization. Hypogene alteration of the quartz monzonite includes the addition of quartz, orthoclase, and sericite and recrystallization of biotite. The hypogene sulphides are pyrite, chalcopyrite, and molybdenite, the latter younger than the chalcopyrite. The late Cretaceous or early Tertiary igneous rocks, veins, and faults were controlled by northeast and northwest shear zones, the intersection of which marks the zone of appreciable copper mineralization. The minor mineralized fractures carrying the bulk of the copper have a preferred orientation parallel to the intersecting shears, and it is concluded that they are of tectonic origin rather than the result of shrinkage on cooling, crystallization, or mineralization. Supergene enrichment during late Tertiary or early Pleistocene time formed a chalcocite zone providing the minable copper ore. The enrichment was controlled in large part by northeast and northwest faults, particularly at their intersection or where the faults are closely spaced.

Jan 1, 1947

By Dorsey Hager

The possibility of oil and gas production in Alabama his been little considered as yet. Gas and some oil have been found in northwestern Alabama, near Birmingham, in the Pennsylvanian beds, but the oil and gas possibilities in the Cretaceous beds are not generally appreciated. The recent activity of oil companies in that State has attracted much attention, and in this paper the main structural and the general strati-graphic features are described. Four favorable areas are outlined. These contain folds of major interest. There are other favorable areas which have not been mapped-l Commercial pools discovered in this area would have the advantage of being near tidewater. Mobile, Ala., on the Gulf of Mexico, would be the logical site for refineries and shipping facilities. A pipe line could readily be laid to that city from the Hatchitigbee and the Jackson areas. The logical outlet for the Geneva and the Gordon areas would be Panama City, Ha., on the Gulf of Mexico. Topography The whole of the area under consideration lies in the Gulf coastal plain and slopes gently to the southwest and west. The elevations vary from 200 to 400 ft. (60 to 121 m.) above sea level. The streams have sunk their channels into this gently sloping plain, the main drainage flowing south or southwest into the Gulf of Mexico. Between the

Jan 1, 1918

By W. V. Vietti, W. A. Oberlin

Crude petroleum produced in the Texas Panhandle oil field is both an asphalt and a paraffin-base oil and is further characterized by being a high-gravity crude with an extremely high cold test,. An eight-well composite of Panhandle crude showed the following characteristics: Gravity, 36.6° A. P. I. Viscosity: 61 sec. Saybolt at 100° F. 170 sec. Saybolt at 75° F. 1560 sec. Saybolt at 50° F. (stirring) Cold Test, 60° F. Distillation Test: Per Cent. Per Cent. Gasoline........................ 28.8 Wax........................... 19.2 Kerosene........................ 4.8 Asphalt........................ 13 .0 Gas oil......................... 30.7 Sulfur1......................... 0.8 Fuel oil......................... 34.7 Subsurface Conditions The original pressure in the formation in the Panhandle field closely approximated 420 Ib. gage or 435 Ib. absolute pressure. Temperatures taken indicate that the formation temperatures do not exceed 90° F. The temperatures in Table I are typical measurements taken on one lease. * A contribrition from the research department of the Marland Refining Co. of Oklahoma and the production engineering department of the Marland Oil Co. of Texas. 1 Smith [Analysis of Panhandle and Rig Lake Crudes. U. S. Bur. Mines, Circular No. 6014 (December, 1926)] found an average sulfur content of 0.6 per cent.

Jan 1, 1928

By William Kent

THE dynamometer herein described is a modification of the one invented by Mr. Samuel Batchelder, of Boston, nearly forty years ago, a description of which may be found in the Journal of the Franklin Institute, 1843, vol. xxxii,.p. 277, and in the Scientific American of August 31st, 1878. The modification consists in providing a method of making an automatic record, and of indicating more minute variations of the power transmitted. The improved dynamometer was designed by the writer in 1877, and was built a few months since by the Class of 1879 of the Stevens Institute of Technology. The accompanying cut, taken from the Annual Announcement of the Stevens Institute, represents the dynamometer without the recording attachment. It consists, as shown, of two stout cast-iron frames, held together by bolts in bearings, in the top of which frames run two shafts, each carrying a pulley at its outer end and a bevel gear-wheel of 45' at its inner end. One of these shafts is the driving-shaft, connected by belt to the engine or other prime mover; the other is the driven shaft, connected by belt to the machine driven. The power is transmitted from one shaft to the other through two other bevel-wheels of 45' gearing with the first, the shaft common to them and on which they run freely being at right angles to the axis of the two shafts first mentioned, and carrying at one extremity a heavy pendulum. The bevel-wheels being connected, as shown, and the power being applied to the driving-wheel, the two intermediate wheels with their common shaft have a tendency to revolve around the driving-axis, which tendency is a measure of the force transmitted, and is resisted by the moment of the weight of the pendulum. In the Batchelder dynamometer the four bevel-wheels and their shafts are used, but

Jan 1, 1880

By A. G. Raine

For the technological age in which we live, with the constant goal of further improvement in the efficiency of mechanized systems, the need for a replacement of the antiquated drill and blast method of shaft construction has been recognized. For over a decade now; the trend in shaft construction has been toward large diameter bored shafts using either raise boring methods or more flexible, rodless "down the hole" boring machine. The limits of conventional shaft sinking have been reached, the mining regulations are more stringent, and the environmental agencies more aggressive, all contributing to the growing need for development of the rodless shaft boring machine. In the last three years in the United States, world shaft construction records have been achieved using a V-Mole machine, designed by Mirth GmbH of West Germany, using American electrics and hydraulics. Shafts of 7.0 meters (23 feet) diameter, totaling 2,255 meters (7,400 feet) in depth have been constructed at high advance rates, yet with unusually low accident rates. Bearing in mind the high cost of today's mining labor and the inherent danger associated with conventional shaft sinking, this alternative method of shaft construction achieves a fast, competitive, low manpower requirement, whilst enhancing a safer environment for the labor force. Recent results have proven that program time savings of 50 percent over conventional shaft sinking can be achieved which can be directly translated into improved client cash flow projections and more accurate project budgeting.

Jan 1, 1984

By Hallan N. Marsh

The subject of this paper is apt to bring to mind wells ranging from 6000 to over 8000 ft. in depth. However, it is uncommon to pump wells at depths greater than about 5000 ft. Fig. 1 shows the number of wells being pumped at various depths by one company in Southern California. A few companies have a very few wells pumping at depths greater than this. This paper will deal with wells between 3000 and 5500 ft. in depth. Most California oils at these depths are between 25" and 35" gravity. The subject is so broad that it will be necessary to omit many interesting phases, and to treat others very briefly. Power, power transmission equipment, power efficiency, counterbalancing, sucker rods, pumps and volumetric efficiency will be discussed. Power As a source of power, the 50/20-hp. electric motor is generally preferred. Input is generally between 10 and 25 hp. Due to the uneven-ness of the load, an input of 20 hp. on the low range is generally about all that these motors will carry without overheating, in spite of their overload capacity. In some cases the capacity of the motor limits the speed

Jan 1, 1929