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By George B. Clark, John W. Brown, Hemendra N. Kalia, Ronald R. Rollins

A new theory for three dimensional collapse of conical liners shows why the two dimensional theory may offer a good approximation. Shaped charge design parameters and rock target properties were investigated to determine their effects on penetration and breakage. Penetration in dolomite is somewhat similar to that in steel, but copper does not have markedly better penetration capabilities than brass. Several metals, liner thicknesses, cone angles and standoff ranges for each were investigated. Effective standoff is greater for aluminum than more dense metals. Optimum geometry appears to approximate that for metal targets. Resistance to penetrations was greatest for a red granite and dense siliceous rocks, and least for dolomite and porous sandstone. Hardness and compressive strength appear to be two important conventional proper- ties. The first order law does not apply to the rocks tested. Dolomite may be drilled with shaped charges, the holes sprung and round blasted successfully.

Jan 1, 1971

By A. S. Richardson

THE rating of a mine ventilation fan, or the characteristic curves illustrating the duty it may be expected to perform under various mine conditions are, in general, determined by the fan manufacturers. The information is of importance to the operator, or engineer, of a mine in many ways. For instance, when an increased flow of air is desired and the fan speed is to be increased, it becomes necessary to know what increase in volume may be expected and what the power requirements will be. In other cases, it may be decided to make changes in the mine to reduce the resistance to the flow of air, or to make changes in the general system of ventilation. Under any changed mine conditions there will be a difference in the duty performed by the fan. When mechanical ventilation is adopted, the factors governing the selection of equipment for the new system include not only the requirements of existing conditions, but also those that may be expected with the development of the property. Efficiency of service is required over a variable range of operating conditions. Characteristic curves, giving the duty performed by their fans under variable resistance conditions, are published by most fan manufacturers. General statements as to the effect of variation in speed of the centrifugal-type fan, under fixed mine conditions, appear in textbooks and trade catalogs. However, to the author both sources of information appear to be unreliable, at least under certain circumstances. The catalog of a leading fan manufacturer says: 1. The volume of air delivered by a fan varies directly as the speed. 2. The pressure, or water gage, produced by a fan varies as the square of the fan speed. 3. The horsepower of a fan varies as the cube of the fan speed. While these statements are accurate when the fan is operating under conditions similar to those that exist when a blower is used to force air through a pipe, they are not correct under mine conditions that are by no means unusual. Such conditions may be found in deep mines operated through shafts, in which a wide range of temperatures may be

Jan 8, 1925

By C. H. Li, R. J. Stokes, T. L. Johnston

Sodium chloride crystals are brittle in the presence of surface microcracks. Water immersion leads to an enhancement of ductility which is retained indefinitely in dry air providing the crystal is dried without leaving a surface precipitate. Storage in a damp atmosphere results in a surface reaction and consequent rembrittlement. Although elimination of surface flaws in ionic solids does not necessarily enhance ductility, there is always a change in the location of the fracture origin. EVER since the original experiments of Joffel there has been controversy over their interpretation and no satisfactory generalized explanation has yet been given. It is generally admitted that when sodium

Jan 1, 1961

By S. LeFevre

THE solution of the housing and sanitation problem in mining communities, keeping in view both economic and humanitarian aspects, demands the best thought of the management of such enterprises. Upon the solution depend the health and comfort of the employee and his family, and as a consequence his contentment and efficiency. The following description covers briefly the methods installed for Witherbee, Sherman & Co. The operation of the system has been for about two years under the direct supervision of T. A. Hammond, Land Agent, and I am indebted to him for a compilation of the results.

Jan 2, 1915

By Grover J. Holt

Open-pit mining on the iron range has been in a stage of transition for several years from the standpoint of mechanization. The most radical change in open-pit mining methods was started in open-pit haulage in 1937 with the departure from the then standard system of locomotive and car transportation and the advent of the heavy duty truck as a replacement. The initial use of trucks was followed shortly by the first installation of a conveyor belt for open-pit ore haulage. The growth of the combination of trucks for gathering units delivering to a conveyor system for transportation out of the pit, has been rapid and this transition appears to have reached a peak in 1949 with locomotives and cars now being used in only a few of the largest open pits. One point which must be considered, if we assume that the maximum equipment change- over point has been reached, is that the largest pits have probably passed their peak of production. Future ore replacement must come from smaller pits wherein the truck conveyor system has done an outstanding job.

Jan 1, 1950

By Stephen E. Merritt, T. Carl Shelton

Surveying and mapping are used to locate and visually portray objects, lines, or areas in relation to a reference point or line. The actual making of the measurements to locate the objects and points falls under surveying while mapping is concerned with putting the survey information into a graphical form. Generally, the type or class of proposed survey depends on the precision required. Some surveys may need only approximate measurements which can be obtained by simply pacing or by using an ordinary measuring tape; others may require much accuracy, thus calling for the use of an engineer's transit or theodolite along with a graduated steel tape for horizontal measurements, or a level and a graduated rod for measuring vertical distances. Mapping is likewise dependent on accuracy requirements. For example, a general layout showing the relative position of surface facilities may not call for a large scale of dimension or great precision whereas for detailed work, a large scale plus care in plotting points and drawing lines and curves are important factors. SURVEYING METHODS There are many kinds or types of surveying methods. Some examples include: land surveying for determining boundaries of land areas ; route surveying for locating roads, highways, right-of-ways, and haulways; city surveying for laying out lots, streets, and alleys ; and mining surveying for projecting mine openings and locating mining operations. There are other types of surveying than those named, but in general, the type of method to be used will depend on the purpose for which the survey is to be made.

Jan 1, 1973

Elected Died 1895 *ABBOTT, AI ATTHUR 1908 1882 *ABBOTT, ARTHUR V 1906 1905 * ABE, MASAYOSHI 1909 1903 * ADAMS, CHARLES C. 1905 1906 * ADAMS, JOHN C. 1913 1905 * ADAMS, WILLAMS 1909 1903 * ADAMS, W. EDWARDS 1910 1884 *ADDY, MATTHEW 1896 1906 * AFFLECK, WILLIAM A. 1911 1889 * AKERS, WILLIAMS 1906 1905 * ALABASTER, RUPPERT C. 1911 1899 * ALBERGER, LOUIS R. 1911 1894 *ALLEN R B 1896 1905 * ALLEN, R. SCOTT 1906 1874 * AMIOT, H. 1892 1886 *AMSLER, CARL 1894 1898 ** ANDRSON, JOHN W 1905 1895 *ÅNGSTROM, CARL 1901 1887 * ARCHBALD, JAMES 1910 1900 * ARLETT, GEORGE H 1906 1895 *ARMSTRONG, JOHN F 1898 1882 *ARNOLDS, HUGO 1886 1875 *ASHBURNER, CHARLES A 1889 1872 *ASIIBURNER, WILLIAM 1887 1883 *ATKINS, C M , JR 1885 1905 * AUSTEN, PETER T 1907

Jan 1, 1917

By T. Sterry Hunt

THE Jones Mine (or Johannes Mine, as it was originally called, from a former proprietor), situated near Springfield, in the township of Caernarvon, Berks County, Pennsylvania, has long been known as a large deposit of magnetic iron ore, associated with more or less copper pyrites, and with malachite and chrysocolla. It occurs in a belt of soft schistose rocks which rest upon the Laurentian gneiss of the Welsh Mountain, and to the northward are soon concealed by the unconformably overlying Mesozoic sandstone of the region. These metalliferous strata belong to the Primal slates of Rodgers, which, in many other localities in this region, include similar deposits of iron ores associated with more or less copper, and often accompanied by chloritic and argillaceous schists, and, more rarely, by serpentine and small lenticular masses of crystalline limestone. To this same horizon belong the iron ores of Boyertown, Fritz's Island, and Roudenbusch, near Reading, Wheatfield, Cornwall, and Dillsburg (all of which are found along the northern border of the Mesozoic belt of * By the kind permission of Dr. F. A. Genth, of the University of Pennsylvania, I am now enabled to append to this paper the following hitherto unpublished analyses of the Cornwall ores.

Jan 1, 1876

By I. R. Kramer

A study was made of the effect of surface-active agents an copper, gold, and zinc single crystals as well as polycrystalline aluminum. The study on coppw showed that the maximum effect of the surface -active agent occurred at the same concentration of the solution as that at which the rate of solution of the copper soap was the greatest. Surface -active agents did not affect the creep behavior of gold or freshly polished zinc specimens. The creel-, rate of zinc specimens in a solution containing a surface-active agent zoas always lower than that of freshly polished specimens. In previous papers1'2 it was reported that the surface played an important role in the plastic deformation of metals. By removing the surface layers of a crystal of aluminum by electrolytic polishing dur- ing tensile deformation, it was found that the slopes of Stages I, 11, and In were decreased and the extent of Stages I and I1 were increased when the rate of metal removal was increased. The results of the investigation of surface-active agents showed that changes in the slopes and extents of Stages I and II occurred when single crystals of aluminum were deformed in tension in a bath containing solutions of paraffin oil and stearic acid. The amount of change was a function of the concentration of stearic acid and the maximum effect occurred at a concentration of 0.002 mole per liter. These results were interpreted2 in terms of the rate of solution of metal soaps which form as a result of the chemical reaction between the surface-active agent and the metal. According to this interpretation, the "weakening" effect is controlled by the rate of solution of the soaps which depends upon the concentration of surface-active agents. At low concentrations, the number of metal soap molecules formed is low; at high concentrations, the rate of solubility is low, because of the high degree of saturation.

Jan 1, 1963

By Arthur Hockman, Howard W. Jaffe, Howard F. Carl

THE problem of establishing practical techniques for evaluating natural corundum ores arose from the desire to improve the existing purchase specifications for crystal corundum procured by the Federal Government for stockpiling. Such purchase specifications had been developed for a large number of products, including minerals and ores considered to be critical and strategic because of the country's dependence on foreign sources of supply. It will be apparent to anyone considering the subject of purchase specifications that the determination of whether or not a submittal meets the specifications is a prime consideration. Consequently satisfactory specifications for minerals should not only incorporate physical, chemical, and mineralogical requirements that are practical but should also establish the means by which both buyer and seller can be assured that materials meet stated requirements.

Jan 4, 1954

By H. W. McCue

In 1945 the number of oil wells drilled was less than in 1944 but the number of gas wells was greater. The oil wells numbered 176, completed for an initial production of 25,214 bbl., an average of 143 bbl. per well as against a total in 1944 of 245 drilled for 32,886 bbl., or 134 bbl. per well. All of these wells were in proven areas and no new discoveries

Jan 1, 1946

By James R. Evans

Forecasting demand is an art as well as a science, and much personal judgment is required. National forecasts made for sand and gravel, crushed stone, and/or aggregate may be misleading or unhelpful locally. This is because of significant variation in demand within different geographic and/or political areas in the US, and/or the use of an inadequate data base and forecasting methodology. The best forecasts may be made for local or regional market areas, irrespective of geographic or political boundaries, provided a proper data base is available.1 The Bureau of Mines compiles detailed statistics on commodities sold or used in the construction industries and, therefore, is in an advantageous position to make national aggregate demand forecasts. Definitions of some terms used in this presentation are necessary before proceeding.

Jan 1, 1980

By H. F. Bishop, F. A. Brandt, W. S. Pellini

M. S. Fisher and D. R. F. West (Imperial College of Science and Technology, London, England)—It may be of value to compare certain features of the results recorded in this very interesting paper with those of an investigation11 involving determinations of temperature gradients and rates of solidification of steel blocks of 3 in. sq section, cast horizontally in sand molds, some of which contained chills. Castings in plain carbon steels containing up to 0.8 pct C were made and, throughout this range of compositions, both inverse-rate and direct cooling curves, obtained from thermocouples placed within the mold cavity, showed a major arrest, the temperature of which was taken as the "effective liquidus" for the particular steel in question, solidifying under the conditions of the investigation. At the completion of the arrest, the curves showed a comparatively rapid de- crease in temperature. Some of the steels investigated lay within the peritectic region, and a second arrest at 1485°C was detected. In Fig. 15, which shows the effective liquidus temperatures, the limit of the 8 + liquid field has been placed at approximately 0.5 pct C. In inverse-rate curves corresponding to the thermal center of each casting, there was always a discontinuity, viz: an abrupt change of slope, at a temperature about 10 to 20°C below the "liquidus arrest," after which there seemed to be no significant irregularity in the rate of cooling. Curves corresponding to other positions in the casting generally showed some irregularities below the main arrest, probably as a result of heat flow from the solidifying interior. Even the reproducible discontinuity in the curves for the central positions appeared to have no theoretical or practical significance, though it probably corresponded to a stage in the solidification process at which only a relatively small amount of interdendritic liquid remained. Its temperature, rela-

Jan 1, 1953

By Robert Ammon

THE milling practice at Mascot, at present, consists of dry crushing to 5/8 in., jigging, fine grinding, and flotation. The ore arrives at the mill from two mines, No. 1 mine shaft being located in the mill proper, and No. 2 mine shaft being situated about 2000 ft. east of the mill. No. 2 mine is served by a coarse-crushing plant and aerial tramway to the mill bins. In jigging the No. 2 mine ore, 50 per cent. of the mill feed is rejected by the jigs as a jig tailing ranging from 5/8 in. to 10 mesh; the balance of this ore, after removing a jig concentrate, is ground to flotation feed. In jigging No. 1 mine ore, approximately 80 per. cent. of the mill feed is rejected as a coarse jig tailing, and the balance is ground to flotation feed without the removal of a jig concentrate. The difference in the treatment is due to the fact that No. 2 mine ore carries a higher content of zinc than that from No. 1 mine. Of the total concentrates produced, 30 per cent. are made on jigs and 70 per cent. by flotation. At present, 1350 tons of No. 2 ore and 800 tons of No. 1 ore are treated each 24 hours. The recoveries for a typical week are as follows: Heads 3.55 Jig concentrates 61.30 Jig tails 0.80 Flotation concentrates 60.60 Flotation tails 0.09 Extraction 86.50 The associated minerals are a straw-colored sphalerite, dolomite, calcite, pyrite, quartz, and a small amount of greenockite, which occurs as a stain and sometimes small crystals along with sphalerite, but is comparatively rare. Pyrite is present in small quantities, usually less than 0.5 per cent.; quartz occurs in bands a few inches thick. A complete analysis of the ore is as follows:

Jan 9, 1924

By Richard P. Rothwell

A REFERENCE to the geological map of Alabama shows the coal- measures of that State to form three distinct fields. The Coosu, or most easterly, contains about one hundred square miles ; the Cahaba, or middle field, which is also the most southern true coal in the United States, contains about 230 square miles ; and the Warrior field, which contains in the State of Alabama some 5000 square miles, is the southern extremity of the great carboniferous deposit, which extends through Pennsylvania, West Virginia, Kentucky, Tennessee, and Georgia. But very little has yet been done towards developing those coal- fields, partly owing to the absence of all commercial manufacturing enterprise in the South under slavery, and partly owing to the want of capital and the disturbed condition of the South since the war. During the past three or four years I have devoted a large part of my time to the examination of the coal and iron ores of this range,

Jan 1, 1874

By J. Versluys

WHEN a well strikes an oil-bearing layer, the oil has a pressure which is generally sufficient to enable it to rise to near the surface (sometimes above the surface). As soon as a well begins to produce, however, the liquid moves through the pores of the reservoir bed and the pressure in the well becomes much lower than the pressure originally prevailing there. At some distance from the well, however, the pressure in the reservoir bed remains unaltered; thus the pressure of the oil has not only to lift the oil, but also to overcome the friction resistance in the pores. The fact that so many oil wells are gushers is a consequence of the energy accumulated in the gas. In gushing the well acts as a gas-lift. A mixture of liquid and gas (the latter partly dissolved in the former) rises vertically from the oil¬bearing layer through a cylindrical casing to the surface. In time conditions alter and the well ceases to gush regularly, then the gushing can be further promoted by inserting a narrower tube in the well and connecting the top of the oil string to the tubing. If the action in time becomes irregular, the gushing can be kept up for a further period by forcing gas between the two tubes. In the oil fields the term "gas-lift" is used actually only where extraneous gas is applied, as in the last of the stages mentioned. The action, however, is just the same whether the gas exclusively originates from the formation, or is partly applied artificially. Thus by gas-lift we simply mean a vertical tube in which the energy of gas under pressure, and of dissolved gas, is utilized for raising a liquid. In gushing oil wells the pressure is frequently very high and the absorption coefficient 0.4 (expressed in vol. ratio) of the coexisting gas is not particularly high, so that in reality it should be assumed that a considerable portion of the gas, at any rate at the bottom of the gas-lift, is dissolved in the oil. For water-producing wells this is not usually of such importance.

Jan 1, 1929

By Park Wright

THE fact that granite has been encountered by the drill by those in search of oil and gas in Kansas is becoming more and more a matter of interest, not only to the oil producer but to everyone directly and- indirectly connected with the oil business. It is, therefore, time that someone should offer an explanation for its presence and form a definite opinion based on all the data available in regard to the effect it will have on the future prospects of the area affected as probable oil- and gas-producing territory. At present there seems to be no consensus of opinion. To the writer's knowledge, only one attempt has been made to explain; by Erasmus Haworth, State Geologist of Kansas, in a paper entitled Bulletin, Number Two on Crystalline Rocks in Kansas. The purpose of the present paper is to offer a theory for the presence of the granite and to draw conclusions which will aid in determining the prospective oil and gas value of the area in question. In taking up this question it will be well to consider first the tests in which granite has been reported, with a general history of each. The accompanying map (Fig. 1) shows the location of all wells described. The first well in which granite was reported was that drilled just south of Zeandale in section 27, township 10 south, range 9 east, by a local company which had taken up a block of leases in that vicinity. At a depth of 958 ft. (291.99 m.) granite was encountered. Drilling was continued to a depth of 1,093 ft. (333 m.) in the same formation, at which depth the hole was abandoned. Another well was started 1 mile east of the first well and the same rock was found at a depth of 945 ft. (288 m.). Drilling was continued to a depth of 1,200 ft. (365.76 m.) with the bit in the sane formation. Samples of the drill cuttings have been examined and they are undoubtedly crushed granite. The next well in which granite was found was that drilled by DeLaat and Shepard, independent wildcat operators, in section 34, township 19 south,. range 7 east, near the town of Elmdale. Granite was struck at 1,707 ft. (520 m.) and the hole was abandoned in the same formation at 2,525 ft. (769 m.). Mr. DeLaat watched the drilling of this well very closely and he has described to me in some detail the formation immedi-

Jan 8, 1917

The Committee on a Standard Gauge have been constantly engaged, since their appointment, in the duties assigned to them.§ They have corresponded with different persons interested in the manufacture and use of gauges in this country, and have received from several of them important information. They have also entered into correspondence with the governments of England, France, Gerniany, and Russia through their Consuls, ant1 with Austria directly. The Consuls of Germany and France

Jan 1, 1879

ON FEBRUARY 4, 1952, the Phelps Dodge Corporation signed Contract GS-00P(D)-12068 with the United States Government. This interesting document dealt with the "Bisbee East" project as part of the Government's program to increase the supply of needed copper by encouraging private enterprise to expand production. The ore deposit involved was a relatively small body of low-grade ore lying east of the remnants of the old Sacramento Hill deposit that was exploited with indifferent success from 1923 to 1931, as related in THE PORPHYRY COPPERS. Planning for the entire enterprise had been directed from the start by Harrison M. Lavender, who in 1945, succeeded Percy G. Beckett as vice-president and general manager for all of Phelps Dodge's Western mines and smelters. The untimely death of Mr. Lavender in 1952 prevented him from seeing his plans brought to fruition; but in his honor the mine was fit- tingly named "The Lavender Pit" and was so dedicated on August 7, 1954. The Copper Queen Branch operates under- ground mines at Bisbee (production in 1955 was 28,000 tons) ; but, as this volume is concerned only with Porphyry operations, this chapter deals only with the Lavender Pit project, or as the Government knows it, Bisbee East. My reason for going into some detail regarding the floor-price contract is that it is fairly typical of contracts made by the Government in connection with a half-dozen other copper-expansion projects; and, incidentally, with various projects involving other strategic metals. Phelps Dodge did not seek a loan or other financial aid. The only encouragement asked consisted of (a) the privilege of a five-year write-off (commonly called rapid tax amortization)

Jan 1, 1957

By C. A. Wright

Since the adoption by the U. S. Bureau of Standards several years ago of specifications for standard 100- and 200-mesh sieves, frequent requests have been received that this Bureau test and certify sieves of other sizes than these. With a view to the adoption of a series of standard testing sieves which might be of use to all industries making fineness tests, this Bureau for two years has been studying the question of such a standard screen scale. Various scales that have been proposed were considered, and information was sought of representative firms in the various industries interested as to their requirements. Manufacturers of sieves have also been consulted as to the desirability of different screen scales and the practicability of their manufacture. As a result of this study of the question, a conference was called at the Bureau of Standards, Apr. 20, 1916, of representatives of various committees of the American Society for Testing Materials, American Society of Civil Engineers, American Institute of Mining Engineers, American Foundrymen's Association, Mining and Metallurgical Society of America, American Water Works Association, American Institute of Metals and the American Spice Trade Association; also representatives of the Committee of Revision of the U. S. Pharmacopæia, the U. S. Geological Survey, the U. S. Bureau of Mines, the U. S. Office of Public Roads and Rural Engineering, the U. S. Office of Grain Standardization and the U. S. Bureau of Standards; also representatives of a number of private firms engaged in industries in which sieves are used, such as the glass, the drug milling, the abrasive, the asphalt, the mining, the spice, the chemical, and the graphite industries; also representatives of the firms in this country manufacturing wire cloth and sieves. This Conference, after considering the various screen scales either proposed or now in use, adopted as a Standard Screen Scale that given in Table 1, and recommends that it be adopted generally by scientific,

Jan 1, 1918