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The Library of the above-named Societies is open from 9 A. M. to 10 P. M. except on holidays. It contains about 70,000 volumes and 90,000 pamphlets, including sets of technical periodicals and publications of scientific and technical societies. Members of the Institute, with few exceptions are forced to spend a portion of their time in localities isolated from sources of information. To these the Library; through its Library Service Bureau, can render valuable service through correspondence; letters requesting information will receive especial attention: The Library is prepared, to furnish references and photographic copies of articles on mining and metallurgical subjects; to determine the existence of mining maps, and to furnish general Information on the geology and mineral resources of-all countries. All communications should be made as definite as possible so that the information received may be what is desired and not include collateral matter which may not be of interest. The time spent in searching for such collateral matter will be saved, and the information will be sent more promptly and in more usable shape. HARRISON W. CRAVER, Director.

Jan 4, 1919

Harrison W. Craver, Director The Library of the above-named Societies is open from 9 A.M. to 10 P.M., except on holidays. It contains about 70,000 volumes and 90,000 pamphlets, including sets of technical periodicals and the publications of scientific and technical societies. Members of the Institute, with few exceptions, are forced to spend a portion of their time in localities isolated from sources of information. To these the Library, through its Library Service Bureau, can render valuable service through correspondence; letters requesting information will receive especial attention. The Library is prepared to furnish references and photographic copies of articles on mining and metallurgical subjects; to determine the existence of mining maps, and to furnish general information on the geology and mineral resources of all countries. All communications should be made as definite as possible so that the information received may be what is desired and not include collateral matter which may not be of interest. The time spent in searching for such collateral matter will be saved, and the information will be sent more promptly and in more usable shape.

Jan 5, 1917

The library of the above-named Societies is open from 9 A. M. to 10 P. M. except on holidays. It contains about 70,000 volumes and 90,000 pamphlets, including sets of technical periodicals and publications of scientific and technical societies. Members of the Institute, with few exceptions, are forced to spend a portion of their time in localities isolated from sources of information. To these the Library, through its Library Service Bureau, can render valuable service through correspondence; letters requesting information will receive especial attention. The Library is prepared, to furnish references and photographic copies of articles on mining and metallurgical subjects; to determine the existence of mining maps, and to furnish general information on the geology and mineral resources of all countries. All communications should be made as definite as possible so that the information received may be what is desired and not include collateral matter which may not be of interest. The time spent in searching for such collateral matter will be saved, and the information will be sent more promptly and in more usable shape. HARRISON W. CRAVER, Director.

Jan 5, 1919

By Richard E. McElvain

The mining and other industries have grown and changed with- respect to their requirements for slurry pumps capable of handling high percentages of abrasive materials. Greater solids concentration, higher heads and pressures, and increased flow arc not possible. Today's equipment delivers up to three times the flow-tonnage and 1.3 times the head per stage as compared with pumps of ten years ago. This results in four times the requirement in size and energy. The new centrifugal pumps are capable of handling these requirements at pressures up to 4826 kPa (700 psi), with 6895 kPa (1000 psi) or more being considered for future systems. The latest pumps, functioning at four times the operating requirement on flow-head, weight eight times more than the previous equipment. Efficiency is increased slightly, to about 75 % to 85%. A testing program on equivalent units has confirmed that the added strength and specific design of heavy-duty pumps can meet demanding engineering objectives. Operating life on difficult-to-pump materials is increased from 500 to over 5000 hours of continuous operation; the ten-fold increase in pump operating time is a major design objective.

Jan 12, 1976

By H. A. Meyerhoff, R. J. Colony

Deposits of iron are widely scattered in the folded Cretaceous rocks and the associated igneous intrusives of Puerto Rico. Most of them are too small for commercial development, but a few have aroused some scientific and economic interest, among them the large body of residual limonite at the west end of the island near Mayagüezl-6 (Fig. 1) and the mixed hematite and magnetite deposit on the southern slopes of the Sierra de Cayey, about four miles north of Arroyo.7"9 Neither of these orebodies has been developed, nor have investigations of the widely distributed deposits of magnetite, which include all the remaining occurrences of iron deserving of economic consideration, proceeded beyond the exploratory stage. With the possible exception of the mixed deposit near Arroyo, the magnetite is directly associated with andesitic and dioritic intrusives, which invade the Cretaceous rock section, and the bulk of it, occurring in calcareous sediments, is clearly of contact-replacement origin. The small deposit on Rio Portugües, north of Ponce, is found in a limestone band near its contact with an andesite dike.10,11 Two deposits of unde-

Jan 1, 1935

By H. A. Meyerhoff, R. J. Colony

Deposits of iron are widely scattered in the folded Cretaceous rocks and the associated igneous intrusives of Puerto Rico. Most of them are too small for commercial development, but a few have aroused some scientific and economic interest, among them the large body of residual limonite at the west end of the island near Mayagüezl-6 (Fig. 1) and the mixed hematite and magnetite deposit on the southern slopes of the Sierra de Cayey, about four miles north of Arroyo.7"9 Neither of these orebodies has been developed, nor have investigations of the widely distributed deposits of magnetite, which include all the remaining occurrences of iron deserving of economic consideration, proceeded beyond the exploratory stage. With the possible exception of the mixed deposit near Arroyo, the magnetite is directly associated with andesitic and dioritic intrusives, which invade the Cretaceous rock section, and the bulk of it, occurring in calcareous sediments, is clearly of contact-replacement origin. The small deposit on Rio Portugües, north of Ponce, is found in a limestone band near its contact with an andesite dike.10,11 Two deposits of unde-

Jan 1, 1935

By Reno H. Sales

Jan 1, 1914

By R. T. Moolick, John E. Neill, O&apos

In selecting a particular stripping method the ultimate aim is the removal of material at the least possible cost. Accomplishment of this goal requires the careful consideration of many factors including geologic and topographic information, proximity of the stripping operation to waste disposal areas, possible problems of land reclamation, types of suitable equipment available, and auxiliary equipment requirements. 4.2-1. Selection of Stripping Methods. The size of an orebody and the distribution of values within that orebody normally will limit the variety of economical stripping methods which need to be considered. Much may depend upon the selectivity required in the mining due to the relationship between ore and overburden, as well as the character of the overburden itself. The following factors concerning the geologic nature and environment of an orebody, as well as the production requirements, must be determined before any selection of equipment is made: 1. The size of the orebody and distribution of the values within that orebody. Is the ore massive or scattered, bedded or disseminated, thick or thin? 2. The nature of the overburden to be removed. Is it a hard dense rock, bedded rock (thick or thin), friable material, earth, sand, elay, marsh, etc.? 3. The character and significance of geologic structures (fractures, faults, shear zones, etc.) associated with the ore occurrence. Are there water bearing formations with resulting water disposal problems? 4. In considering the nature of the overburden, including its alteration products, the physical or chemical conditions which, when combined with anticipated climatic conditions, may render certain equipment inoperable during unfavorable seasons.

Jan 1, 1968

By Jim V. Rouse

There have been many changes in environmental control techniques since the early days of uranium mining and milling, when liquid mill effluents and often mill tailings were discharged directly into nearby streams. With today's stringent environmental controls, the uranium miner must be as aware of regulatory requirements as he is of techniques in mining, milling, and in-situ recovery. The time delays involved in bringing a uranium project on line dictate that the proposed facility be designed with a view not only of present regulations, but also of those which may be in effect when the facility is completed. While such predictions are difficult, it's almost certain that regulatory agencies will exercise even more environmental control over future uranium mining and milling operations, using the past errors of the 1950's as justification for increasingly stringent controls.

Jan 10, 1978

By Morris Cohen

NO slackening of research and development in the physical metallurgy of iron and steel was evident in 1943-our second year since Pearl Harbor. Of course, many of the achievements were of a military nature, and could not be reviewed here even if they were known to the authors. It is an open secret that far-reaching investi¬gations have been undertaken in governmental, industrial, and university laboratories, and it is strongly hoped that much of this work will be brought to light when peace comes. However, despite the metallurgist's wartime assignments and the necessary restrictions on his reports he has still managed to publish substantial contributions to the knowledge of iron and steel. This has been particularly true in the United States; foreign papers have been too uncertain in their arrival to permit a comprehensive appraisal of developments abroad.

Jan 1, 1944

By T. F. Witherbee

(Read at the Amenia Meeting, October, 1877.) THE subject of an article in the Engineering and Mining Journal for October 13th, 1877, namely, Blast Furnace Treatment of Silicious Iron Ores,, is of great interest to myself, and doubtless to many others who have been troubled with a seemingly unaccountable percentage of silicon in their pig iron. It is to be regretted that the author of the article did not give us complete details of his charges, and thus prevent a possibly fatal error in the very beginning of the discussion of the points raised in his communication. As it now stands, I think we will have to fall back upon the statement that, "every conceivable mixture of fluxes and ores (A and B) has been used." Let us first, in order to simplify the calculations, do with the

Jan 1, 1878

By J. L. Wilson, D. L. Emmons

The Tucker Hill perlite deposit is located in the northwestern portion of the Devils Garden lava field in Lake County, south-central Oregon. The perlite occurs in the chill margin of a late Miocene composite rhyolite lava dome that exhibits distinct cooling zonation. The chill margin is composed of an outer glass envelope, which contains commercial-grade granular and vesicular perlite, and an inner glass envelope, which contains onionskin perlite of local commercial quality. Glassy rhyolite and rhyolite compose the lava dome core. The entire dome complex encompasses at least 5 km2 (2 sq miles). Expansion tests in commercial-scale furnaces indicate that the perlites are suitable for a wide range of applications and compare favorably with commercial perlite ores. The large tonnage deposit appears competitive for markets in the midwestern and upper northeastern states, and the Pacific Northwest of the US.

Jan 1, 1986

By D. F. Atkins, B. A. Rogers, E. J. Manthos, M. E. Kirkpatrick

A phase diagram of the uranium-columbium alloys is presented. The apparatus and the procedures used in obtaining the data are described. Data from which the diagram was drawn are given in tabular and graphic form. THE use of uranium in the production of energy from nuclear fission has given considerable im- petus to the investigation of the metal and its alloys. Accordingly, information concerning the phase diagrams of binary alloys of uranium with other elements is of interest to metallurgists engaged in nuclear-engineering activities. As a contribution to the knowledge of the binary alloys, the authors have attempted to establish the diagram of the uranium-columbium system. The reports of laboratories engaged in work for the Manhattan Engineering District and the U. S. Atomic Energy Commission contain a number of references to work on uranium-columbium alloys.

Jan 1, 1959

TO THE BOARD OF DIRECTORS OF THE AMERICAN INSTITUTE OF MINING AND METALLURGICAL ENGINEERS Gentlemen:-To a Board of Directors keeping in as close touch with all of the affairs under their care as do the Directors of the A. I. M. E., through their monthly meetings, a report of the year's progress is almost superfluous. ' To the members who read the monthly reports of the Board Meetings and of the various activities of the Institute as published each month, a yearly report cannot carry much fresh information; yet for both it may be well, as is the custom, to glance over the field of our activities during the past year, and to make an estimate for the year to come. The beginning of 1924 was not propitious for the members of the mining profession, though tonnage production for 1923 had been high and the gross value higher than for several years. The margin of profit had been narrow, prospecting and development were limited, and many of our members were unemployed or were working in other industries. Toward the end of the year, higher metal prices were in sight. Old-time optimism began to grow, and it now brightens the outlook for 1925. An excellent barometer of the prosperity of the industry, and that of the Institute, for they go hand in hand, is the work of our Employment Bureau. During the past few months, the percentage of our members for whom openings have been found has been increasing to a marked extent, and many members who had fallen in arrears are placing themselves in good standing. The number of new members joining has remained about as it was in 1922 and 1923. The Directors have reason to congratulate themselves on the interest maintained during a dull period, for it is not humanly possible to take a keen interest in the technology of an industry when our hands and minds are not actively engaged in it Now, with a much brighter outlook, we can look forward to a year of increasing prosperity for the industry and for the Institute.

Jan 1, 1925

Report of the Secretary TO THE BOARD OF DIRECTORS OF THE AMERICAN INSTITUTE OF MINING AND METALLURGICAL ENGINEERS Gentlemen:-To a Board of Directors keeping in as close touch with all of the affairs under their care as do the Board of Directors of the A. I. M. E., through their monthly meetings, a report of the year's progress is almost superfluous. To the members who read the monthly reports of. the Board Meetings and of the various activities of the Institute as published each month, a yearly report cannot carry much fresh information; yet for both it may be well, as is the custom, to glance over the field of our activities during the past year, and to make an estimate for the year to come. The beginning of 1924 was not propitious for the members of the mining profession, though tonnage production for 1923 had been high and the gross value higher than for several years. The margin of profit had been narrow, prospecting and development were limited, and many of our members were unemployed, or were working in other industries. Toward the end of the year, higher metal, prices were in sight. Old-time optimism began to grow, and it now brightens the outlook for 1925. An excellent barometer of the prosperity of the industry, and that of the Institute, for they go hand in hand, is the work of our Employment Bureau. During the past few months, the percentage of our members for whom openings have been found has been increasing to a marked extent, and many members who had fallen in arrears are placing themselves in good standing. The number of new members joining has remained about as it was in 1922 and 1923. The Directors have reason to congratulate themselves on the interest maintained during a dull period, for it is not humanly possible to take a keen interest in the technology of an industry when our hands and minds are not actively engaged in it Now, with a much brighter outlook, we can look forward to a year of increasing prosperity for the industry and for the Institute.

Jan 3, 1925

OFFICIAL INSTITUTE REPORTS FOR THE YEAR 1924 Report of the Secretary TO THE BOARD OF DIRECTORS OF THE AMERICAN INSTITUTE OF MINING AND METALLURGICAL ENGINEERS Gentlemen -To a Board of Directors keeping in as close touch with all of the affairs under their care as do the Directors of the A -I M. E, through their monthly meetings, a report of the year's progress is almost superfluous To the members who read the monthly reports of the Board Meetings and of the various activities of the Institute as published each month, a yearly report cannot carry much fresh infor¬mation, yet for both it may be well, as is the custom, to glance over the field of our activities during the past year, and to make an estimate for the year to come The beginning of 1924 was not propitious for the members of the mining profession, though tonnage, production for 1923 had been high and the gross value higher than for several years The margin of profit had been narrow, prospecting and development were limited, and many of our members were unemployed or were working in other industries Toward the end of the year, higher metal prices were in sight Old-time optimism began to grow, and it now brightens the outlook for 1925 An excellent barometer of the prosperity of the industry, and that of the Institute, for they go hand in hand, is the work of our Employment Bureau During the past few months, the percentage of our members for whom openings have been found has been increasing to a marked extent, and many members who had fallen in arrears are placing themselves in good standing The number of new members joining has remained about as it was in 1922 and 1923 The Directors have reason to congratulate themselves on the interest maintained during a dull period, for it is not humanly possible to take a keen interest in the technology of an industry when our hands and minds are not actively engaged in it Now, with a much brighter outlook, we can look forward to a year of increasing prosperity for the industry and for the Institute

Jan 1, 1923

By E. T. Cox

The Albion phosphate-district embraces a territory about 4 miles wide and 6 miles long, in a northerly and southerly direction, situated in Levy county, Florida. The Florida Central and Peninsular railroad, running from Fernandina, a shipping port on the Atlantic, to Cedar Keys, on the Gulf of Mexico, passes through the center of the district. The post-office and railroad station is in the town of Albion. The physical features of the district present a series of white aqd whitish-gray sand-hills and ridges, rising about 130 feet above tide-water. The sand lies in a loose body, like that seen on the ocean beaches. In places the hills have the appearance of sand-dunes, such as are seen along the Platte river, in Nebraska. Beneath the sand are found the phosphate-deposits, which are partially exposed in places, but, for the most part, lie buried to a depth of 15 feet and more. In this district the phosphate is designated as " hard rock,"

Jan 1, 1896

By Vernon Read

Among the technical problems in AEC's Project Plowshare is the necessity of determining the precise effects of nuclear blasts in all kinds of ground formations. This calls for extensive in-situ sampling with full core recovery. In the exploration drilling that often precedes a new test detonation, the AEC and its contractors have applied both novel and established sampling techniques in many new ways, giving improved core recovery and reduced costs in all subsurface sampling and testing. Unique among these new techniques is one that achieved full recovery and virtually undisturbed samples from near-surface layers of unconsolidated boulder-strewn alluvium. This approach involves a combination of oilfield and mining core drilling equipment. Oilfield heavy drill collars, rotary stabilizers and thick, vibration-reducing oil emulsion drilling mud were used in combination with the precise hydraulic feed control, fast (over 300 rpm) bit rotation, light drilling weight, hard rock core barrels and multi-step diamond bits that are common in mining industry diamond drilling.

Jan 8, 1963

By Jose Luis de Valle Alonso

Although present electrolytic zinc manufacturing processes are aimed at the direct wet process recovery of the metal, and, with this end in view, several industrial scale patents have been applied for during the last few years, the object of this paper is to enhance the possible metallurgical interest in the conventional recovery of zinc and other metals from leaching residues. Therefore, its main end is the description and discussion of the recovery process of zinc, lead and cadmium from leaching residues. Fundamentally, the process consists of the following: Flotation processing to recover the non-roasted blende still contained in the residues. Pyrometallurgical processing of flotation tails in low-shaft furnaces (kilns) and open-flame rotating furnaces and the ensuing recovery of zinc, lead and cadmium as a mixture of their oxides through volatilization.

Jan 1, 1970

By Robert L. Taylor, Richard E. Goodman

A complete rational analysis for design of excavation slopes and loaded rock masses is a desirable but perhaps unattainable goal. Irregular external and internal boundary conditions, poor understanding of failure criteria for large masses of rock, capricious material properties, and the importance of indeterminate forces and inaccessible and virtually unsampleable rock defects emphasize the importance of experience in this aspect of rock engineering. The experience must be correlated with geological factors. In certain regions the accumulation of such experience through the observation of existing rock slopes in various formations constitutes an important aspect of studies for design of rock excavations. In former times an accepted method of rock construction consisted of trials and adjustments. This approach is not often compatible with present methods of contract management. With the development of improved instruments and warning devices such as inclinometers, piezometers, relays, stress meters, and rock noise detectors, modified trial procedures of rock construction may reappear in specific applications. In spite of the great advances made, development of methods to predict the performance of rock slopes, abutments, and foundations deserves vigorous effort. Two distinct approaches may be taken. The rock mass in question may be considered a continuum and the stresses and strains throughout the region of influence of the work may be calculated. Or, the rock mass may be described as a discontinuum whose stability calculation involves the statics and kinematics of accumulations of rigid blocks. The prototype must lie in the range between these contrasting models. As yet, however, there is little reconciliation between the two methods

Jan 1, 1967