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By MARK H. LAMB

(Canal Zone Meeting, November, 1910.) THE recent growth of a sentiment among cyanide-plant designers against the use of gravity-stamps for the crushing preliminary to cyanidation may be said to date from the almost simultaneous perfection of the ribbed tube-mill liner and of the tall, air-agitation tank. The first step in the resulting change of practice was the universal adoption of the tube-mill for fine-grinding and the use of coarse screening oil the battery. This was the beginning of the surrender of supremacy by the gravity-stamp ; since merely the single fact that it was a more economical machine for crushing fine had retained it in favor as compared with ball-mills, rolls, or steam-stamps. The surrender, however, is not yet complete. It is the universal practice to use rolls where a relatively small tonnage is to be crushed coarse, as, for example, when coarse concentration is included in the plan of treatment. Power, attendance, repairs, and first-cost are smaller for the rolls, under such circumstances, than for stamps; and it is becoming daily more apparent that, with no concentration to provide for, the use of rolls and tube-mills, without the complication of trommels and elevators required by concentration, is rapidly gaining favor in the eyes of the leading designers. The next step was the use of the rapid-running Chilean mill between the gravity-stamps and the tube-mill, which again narrowed the field of operation of the gravity-stamp while radically widening its screen-aperture. Such a combination of stamps and Chilean mill offers advantages when fine concentration is necessary, since the reduction in the Chilean mill call be adjusted easily and governed by varying the screen-mesh. But even concentration is now looked at askance. One of the leaders of this metallurgy has abandoned the separation and

Jul 1, 1910

By W. D. BRENNAN

AS a rule the thoughts of engineers are more often directed toward the mechanical and physical conditions of mining practice than they are toward the disposition and the marketing of the product. This, I think, has been true of the coal industry to the present time not only among the engineering force but also generally true of operators. There has been a tendency to place the sales department in a rather secondary position; for a great many years there was a greater demand for coal than the supply would meet, so it was only necessary to increase production: either by expansion of operating mines, or opening new mines of greater capacity. While the production of coal is still a highly important phase of the industry, its enormous development throughout the country, the great advance in fuel, efficiency and economy, and the discovery of new reserves of competitive fuels have combined to create a buyers' market and force the present-day attention upon merchandising in modern ways. A buyers' market has a natural tendency to develop the keenest competition, frequently unscrupulous and nearly always profit-wrecking. Under such conditions bad practices are bound to grow and to extend until the industry is wrecked, or until wiser heads get together to reduce or eliminate unfair methods of competition. This is not so recent a condition as one might believe.

Jan 1, 1931

By E. DeGolyer

USE of geophysical methods as an aid to prospecting for new oil pools and in the exploration of already discovered pools continued to increase and reached a new high during 1934. As in previous years, the scene of greatest activity was the Gulf coastal plain of Texas and Louisiana. Seismic crews working by the reflection method increased from some thirty crews at the first of the year to forty crews at the end. An increased demand for torsion balance work at the beginning of the year occurred and practically all available instruments were put into service. Some thirty crews with approximately eighty balances continued throughout the year. Both the pendulum and gravimeter methods of gravity surveys registered their initial successes and equipment was increased from five to seven pendulums and from one to three gravimeters during the year. Approximately five magnetometer parties continued to work throughout the year. No surface surveys by the electrical method are known to have been made. Outside of coastal Texas and Louisiana the chief geophysical work

Jan 1, 1935

By F. W. Bradley

MY first Nevada City mining reminiscence is one of seeing Capt. Thomas Mein, over 52 years ago, in the old Wyoming mill on Deer Creek about a mile below the town of Nevada City. Captain Mein was then superintendent of the Wyoming mine, where the old fashioned Cornish pump was used, as well as hurdy-gurdy water wheels for power. This mill was one of the typical, up-to-date mills of that time and consisted of stamps, fed by Chinese hand feeders, who also cobbed the ore down to a small enough size to be fed into the mortars. Stamps at that time were of light weight and crushed about one ton to one and a half tons to the stamp, the pulp going over plates, then into sluices with self-raising gates. When a sluice became full the pulp was shut off and directed into the parallel sluice, also with a self-raising gate. The concentrate thus collected in the sluice was shoveled out and carried to Cornish buddles and there cleaned up, preparatory to being sent to a local custom chlorination works.

Jan 1, 1929

By E. B. BESSELIEVRE

THE great work of Gorgas in stamping out yellow fever in Panama during the construction of the Canal was one of the chief factors contributing to the ultimate accomplishment of the task, two previous attempts having failed largely through the demoralization of workers by epidemics of contagious diseases. Mining camps, rapidly constructed during the boom days of the rushes to new fields, have been frequent sufferers from typhoid when, as so often used to be the case, little or no attention was given to bacterial examination of the water supply or to the method used for disposing of the sewage.

Jan 1, 1930

By THOMAS S. MENNIE

ON GORE Mountain, about four and a half miles, southwest of the village of North Creek, Warren Co., N. Y., are the Barton Mines. Here is the largest known deposit of garnet in the world. This property is owned by H. H. Barton &: Son Co., of Philadelphia, and is being worked under lease by Barton Mines Corpn. North Creek is the terminus of the branch of the Delaware and Hudson R..R., which runs into the

Jan 1, 1925

By Donald P. Richards, John F. Abel

Geotechnical site investigation for new mine shafts can reduce the level of design uncertainty for shaft linings. The parameters which determine the lining strength required include rock strength and hydrologic properties, the in situ stress conditions, and the concrete strength. These parameters are applied to analytical methods of shaft lining design using the plastic and clastic assumptions of rock response to determine the required lining thickness to maintain the stability of the shaft excavation.

Jan 1, 1982

By John D. Erickson, Thomas R. Carlson, Milton T. Pana, Daniel T. O’Brian

Computer use in mine planning has evolved from theory to practical application at the Bingham mine of Kennecott Copper Corp.’s Utah Copper Division. Traditional mine planning methods have been combined with computer technology to produce a more realistic calculation of ore reserves and mining plans. The techniques used are not revolutionary but are an expansion of previous mine planning methods using the calculating power of the computer. These methods can readily be adapted for planning use by practical mining men.

Jan 5, 1966

Data for 1962 world-wide, non-communist bloc geophysical activity, including geochemistry, are now available through the Society of Exploration Geophysicists. This information was made available to the AIME Geophysics Unit Committee through the courtesy of Charles L. Elliot, Mining Coordinator for the SEG. The data were compiled from 245 responses to 496 questionnaires mailed (49%). The data for the U.S. are a realistic representation of actual activity, followed by Asia, Canada, Europe, Australia, Africa and Latin America in order of decreasing reliability.

Jan 9, 1963

By Philip D. Wilson

WHEN the United Nations win the war and the decision has been made to control future armament in the Axis countries, plans for the extent and operation of such control must have been prepared, to be ready to put into immediate execution. Such control to be effective must be premised upon complete military occupation of the two countries for a substantial period, with an arrangement at the end of such occupation for continued supervision of these industries into an indefinite future.

Jan 1, 1944

As a means of lending weight to the activities of its Committee on Industrial Organization, with particular reference to the work on mental hygiene and the prevention of illness, the Institute has recently invited a number of members of the medical profession to become Associates of the Institute. We are glad to observe that the wisdom and utility of this departure have been appreciated by the gold mining industry, in testimony whereof we are pleased to publish the accompanying sketch from the pen of Mr. P. A. Robins, Managing Director of the Hollinger

Jan 8, 1918

By Freeman Bishop

Nothing has disturbed the copper- lead-zinc producers in recent years more than smelter tolerances set by some states. What hurt most, copper spokesmen told the Government, was the Government's own erroneous estimates of smelter pollution controls. Government charts indicated that 23 firms smelting copper, lead and zinc may need to invest about $108 million by fiscal 1976 to control stack emissions. The copper industry's independent study, however, indicates that the required controls could cost as much as $550 million to install and $200 million a year to operate.

Jan 1, 1971

By Irwin Roman

PART I. INTRODUCTION THE literature of geophysics as applied to the discovery of mineral deposits has been very extensive during the past few years, but there seem to be few references to the use of the method of least squares for obtaining better interpretations of the observed data .2 There seems to be a general reluctance among geologists and. engineers to acquire the technique of least squares, in spite of the fact that a thorough knowledge of the theory is not necessary for the use of the method.

Jan 1, 1931

By WALTON H. HAMILTON

THE demand for "production control" has, like the poor, been with us always. With the development of the nation, the accumulation of business experience, and a maturing understanding of how our many and varied industries work, it is increasingly evident that an uncontrolled output is a source of great mischief and that order and performance demand a control of production. To see clearly the demand for "production control" we must look in detail at the ways in which industries operate. General pictures, grand aggregates, situations as "wholes," and smoothed curves are likely to be deceptive. An industry may seem to keep the even tenor of its ways, and yet the establishments which made it up may experience a great range of fortunes. A nice bundle of statistics may show in the aggregate a lovely regularity which is not shared by the firms which make up a trade. An industry may appear to be reasonably profitable, and yet the profits may be very unevenly distributed. The people in an industry, and dependent on it, are managers, laborers, stockholders, creatures of flesh and blood, such as you and I. General pictures and abstract statements must not blind us to what is happening to firms, corporations and individuals.

Jan 1, 1929

By George W. Pawel

OWING largely to its value as a toughener and strengthener of steel for both industrial and military purposes, nickel is playing, an important role in the current war. It is fine of the metals in which the Allies enjoy a definite edge over the Axis nations and this time there is no place to which the Germans may send another submarine "Deutsehland" and expect to pick up a cargo of nickel to replenish their exhausted supplies. Total world nickel production thanks almost entirely to the expanded operation of the International Nickel Co. of Canada at Sudbury must now be at the rate of around 175,000 tons a year scarcely more than 5 per cent of which is accounted for by Germany, Italy and Japan. This represents more than four times the world output at the end of the first World War.

Jan 1, 1943

THE term mountain bump describes the sudden rupture of one or more coal pillars under excessive stress. These bursts occur with varying degrees of violence and sometimes include adjacent strata, especially the bottom rock. Many failures do not develop enough violence to be dangerous and are regarded as an aid to coal production, but severe occurrences are accompanied by tons of flying coal, dense clouds of dust, and excessive gas emission. Such bursts sometimes throw heavy machinery several feet. Major factors to be considered in the problem are the nature of the strata above and below the seam and the depth of cover. Bumps are classified as to their nature, extent of damage, and point of occurrence, e. g., face bump, coal bump, high side bump, low side pavement bump, and district bump.

Jan 8, 1958

By C. L. HUNTZINGER

THE mine here described is in the Witbank district, a coal area of the Transvaal, about 100 miles north- east of Johannesburg. and is owned by the Witbank Colliery, Ltd. The plant has a capacity of 4000 tons per eight hours, and prepares five sizes of coal. The coal seam lies at a depth of about 200 ft. below the surface, and is reached by an inclined shaft sunk at an angle of 18° with the horizontal. Although the thickness of the coal seam varies from 10 to 14 ft. or more, only about a 7-ft. bench is mined. Mining is by the hord and pillar system. Bords are driven 18 ft. wide, with pillars measuring 18 ft. square. The mine is laid out into four sections, each sewed by a main haulage way from the shaft. Arc-wall machines are used for cutting the coal. but all loading is done by hand. Native labor is employed under the supervision of white miners, who do the required blasting. The workings are practically free from gas and water, and very little timber is needed.

Jan 1, 1931

By A. L. Moore

KAISER Bauxite Co., a subsidiary of Kaiser Aluminum & Chemical Corp., has been mining and shipping Jamaican bauxite for over a year. On Feb. 10, 1953 the first boat load of bauxite left Port Kaiser, Jamaica, for the company's alumina plant at Baton Rouge, La. To provide its own source of the aluminum ore, a Kaiser Aluminum & Chemical Corp. exploration party started initial reconnaissance in 1947. This work, and subsequent exploration, led to the acquisition of reserves sufficient to warrant a full-scale mining operation for several decades.

Jan 3, 1954

By James W. Halley

' FINE-GRAINED " steels have been standard products for many years. This paper describes an investigation of the effects of some of the more common grain-growth; inhibitors used to produce these steels. The properties, response to heat-treatment, and the deoxidation practice necessary to produce "fine-grained" steels have been the subjects of numerous papers. It has been shown that a substantial quantity of' aluminum is necessary to produce this type of steel, and it has been indicated that titanium and zirconium produce a similar result. For some time there was a lively argument between those who felt that aluminum refined the grain and those who felt that aluminum oxide was the effective agent. This argument subsided with an apparent victory for those promoting aluminum oxide. Most of the work on grain size has divided steels into two broad classifications based upon McQuaid and Ehn's original carburizing test at 1700°F. or some similar test at this temperature. If the steel coarsened at this temperature, it was coarse grained, while if it did not it was fine grained. Quantitative data concerning how much a certain amount of aluminum raised the coarsening temperature and affected the properties, all other factors being constant, are very meager. Similar information regarding titanium and zirconium is practically nonexistent. The published information on aluminum yields some quantitative information. Epstein, Nead and Washburn' gave the first quantitative information on the amount of aluminum necessary to prevent grain growth at 1700°F. They showed that the addition of a pound to a pound and a half of aluminum per ton (0.05 to 0.075 per cent) would assure steel that would not .coarsen during a McQuaid-Ehn test at 1700°F. Herty, McBride and Hough2 reported that a steel containing 0.020 per cent acid-soluble aluminum coarsened between 1742° and 1832°F., while steels containing 0.016 per cent and 0.017 per cent acid-soluble aluminum coarsened between 1652~ and 1742°F. compared with similar aluminum-free steels that started to coarsen at 1580°F. Herty3 also showed a marked improvement in low-temperature notched impact resistance with increasing acid-soluble aluminum up to 0.030 per cent. McQuaid4 compared the coarsening of steels containing 0.011 to 0.204 per cent total aluminum and found a maximum coarsening temperature at 0.098 per cent aluminum. He had no samples between 0.015 and 0.098 per cent aluminum. Houdrement5 found a marked decrease in coarsening temperature with aluminum contents above 0.50 per cent. Kinzel, Crafts and Egan6 found that aluminum and zirconium improved thy low-temperature impact resistance of a low-alloy steel, while titanium was detrimental. Sims7 shows that sulphur increases the coarsening temperature and that the maximum coarsening temperature is between 0.04and 0.06 Per cent added aluminum. The

Jan 1, 1946

By the courtesy of Sir Robert Hadfield, we have received the fol¬lowing communication relating to the development and encouragement of science and research in Germany at present. These statements have been translated by Sir Robert from various German sources, and are presented here as an indication of what Germany is doing not only to further her military power, but also to prepare for the period of trade rehabilitation to which she is looking forward after the close of, the war. KAISER WILHELM TRUST FOR PROMOTION OF WAR SCIENCE The Kaiser has approved the foundation of a Trust with the name given above. The aim of the Trust is to further the development of scientific and technical aids to warfare, by uniting the scientific and the military forces of the country for work together. The scientific Work is to be carried on by the following technical committees (or commissions) (1) Committee for the chemical raw materials, for the production of munitions-manufacturing materials. (2) Committee for chemical war materials (powder, explosives, gas, and the like). (3) Committee for physics, including ballistics, telephony, telegraphy, determination of targets and distances, measurements, and the like. (4) Committee for engineering and communication. (5) Committee for aeronautics. (6) Committee for obtaining and preparation of metals.

Jan 8, 1918