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Today's largest producer of domestic beryllium oxide, Mineral Concentrates & Chemical Co., Inc., has recently disclosed the basic outline of its unique process of beneficiating beryllium ores to high purity BeO. This process, known as the Mincon process, is a thermic-flotation scheme which has reportedly resulted in a recovery ratio exceeding 90% and in allowing up-grading of beryllium concentrates to as high as 33%. Mincon borrowed a step from the iron ore industry by introducing a pelletizing and sintering stage in their flow sheet at the company's mill at Loveland, Colo. This mill, now operating at full-capacity with three-shifts a day, is still undergoing some minor changes and adjustments in the equipment and chemical reagents.

Jan 10, 1961

By M. H. Harrington

The Transaclions of the Institute afford abundant evidence of the general recognition by mining engineers of the importance of a safety-lamp which will not only give warning of the presence of fire-damp, but will also indicate the proportion in which it is present.' Mining-men are only too familiar with the frequent and sudden changes that habitually occur at the working-face of a gaseous mine. Nothing illustrates more forcibly the pregnant condition of the strata enfolding the seam and the seam itself, than the fact that a circulation of perhaps 150,000 cu. ft. of air

Jan 1, 1907

By H. L. Armstrong

SOLID-STATE diffusion is an important technique in certain aspects of metallurgy, and especially the metallurgy of semi-conductors and semi-conductor devices. If the diffusion is carried out under constant conditions for a time, t, the concentration, C, of the diffusant at a depth, x, below the surface from which the diffusion is carried out is given by an expression of the form. C = Cof(x,Dt) [I] Co being a constant, and D the diffusion constant of the diffusant in the material and at the temperature

Jan 1, 1959

In uranium metallurgy, the main purpose is to obtain a product containing 80-85% U308 (yellowcake) from ores whose average grade is a mere 0.21% U30& Essentially, the task of extraction and concentration involves dissolving the ore's U308 values, followed by purification and concentration of the uranium-rich solution (using such operations as filtration, clarification, and ion-exchange), and then selectively precipitating and isolating U308. Leaching is First Step In yellowcake production mills, the first chemical change occurs by leaching the ore with either sulfuric acid-as done by Anaconda and Kerr-McGee-or with an alkaline solution of, say, sodium carbonate, as done by United Nuclear-Homestake Partners. The choice of either acid or alkaline leaching is not an arbitrary one: it depends on the chemical and physical characteristics of a particular ore. That is, on the presence of clays, organic compounds (usually of carbonaceous origin), and soluble impurities, as well as on the ore's wetness and grindability.

Jan 8, 1974

By B. R. Eichbaum, J. E. Murphy, J. A. Eisele

The US Bureau of Mines demonstrated ferric chloride leaching of galena concentrate on a continuous bench scale basis. Leaching was performed at 95°C (200°F) and with a contact time of 15 minutes. The ferric chloride leaching solution was continuously fed to a leaching tank at a constant rate for periods up to 45 hours. In each test, a constant redox potential was maintained in the slurry exiting the leaching tank by controlling the concentrate feed rate. In the 45 hour test, lead extraction exceeded 99.5%, and the lead chloride produced was 99.97% pure.

Jan 1, 1986

By I. E. Rosenzweig

GeophyGical prospecting by earth-resistivity methods is frequently applied to investigation of structural problems in geology. Fig. 1 indicates a scheme of the general arrangement used in these methods of measurements. The battery (or generator) E is connected with two "current electrodes" I1 and I2. The current of intensity J, supplied by this battery, passes through the earth between these elcc- trodes. A potential difference U will be measured between two other electrodes V1 and Vz, called "potential electrodes." According to the configuration of electrodes (Fig. I), the resistivity of a homogeneous soil results from the formula p — 2rca-j [1] where 1 C = -------------------------------------- a a 1 a a [2]

Jan 1, 1940

By Robert E. Delavault, Harry V. Warren

Circumstances determine whether it is better to make analyses in the field or in a permanent laboratory. The rubeanic acid test described in this article has been designed primarily for field use: it is simple and virtually foolproof, and it requires a minimum of field kit.* It is sensitive, easily detecting 4 ppm of readily extractable copper in a soil. This is by no means a quantitative test, but it is accurate enough to provide a valuable indicator of copper anomalous areas for both prospectors and field geologists. The easiest method for detecting metal deposits that do not produce visible float or stains is to make a simple chemical test for the metal in overlying soil, or in the silt of a stream that may have picked up metal farther upstream.

Jan 11, 1958

A. A. Almstrom is mill superintendent for Barrue Mines, Barraute, Quebec. Frank A. Ayer, vice president of Copper Range Co., who has been in charge of the development and bringing into production of White Pine orebody in northern Michigan, has resigned. E. G. Bailey and H. S. Mudd were made honorary members of the American Society of Civil Engineers. Lee Bilheimer, graduate of Missouri School of Mines, has been employed as assistant mine captain at the Edwards, N. Y., div. of the St. Joseph Lead Co. Douglas C. Blackwell, recently graduated from the South Dakota School of Mines, is now with the Oliver Iron Mining Co. of Duluth, Minn. Joseph F. Brown has joined the Grand Junction Exploration Branch of the United States Atomic Energy Commission as a geologist.

Jan 1, 1952

By John D. Erickson

The concepts of long-range, open pit planning presented here are not new. The new idea is how the factors that control the location of the final pit limits can be considered altogether as one large, simultaneous equation. The X, or unknown quantity that is being solved for, is a long-range pit design that fulfills the desired objectives. The objectives of a final pit plan are determination of the extent and location of ore reserves, the allowable stripping necessary to uncover the ore, the final pit surface intercept, final pit topography and the contained metal values in both ore and waste.

Jan 4, 1968

By Milton Glicken

The airborne geophysicist is a busy man these days. In his plane he may have the airborne magnetometer, the airborne scintillation counter, and the airborne electromagnetic surveying system. Each of these is an independent tool, but all require additional auxiliary equipment for locating the aircraft in space: recording altimeters and Shoran or aerial cameras. Now there is still another piece of equipment, the airborne magnetic gradiometer, an accessory to the magnetometer. To understand its uses, consider the function of the magnetometer itself. Aside from detecting magnetic ore, the airborne magnetometer finds greatest use in spotting intrusions of igneous material. Where there is enough contrast in magnetic susceptibility of igneous rock and adjacent formations, it outlines the intrusion. Certain minerals also influence the magnetometer directly, but with the exception of magnetite and possibly one or two others, their effect is weak and can be detected only when there is sufficient ore and the magnetometer flight passes very close to it.

Nov 1, 1955

By George B. Clark

More economical methods of rock disintegration are needed for mining and for rapid excavation. Two major systems are drill and blast and mechanical excavation, including tunnel-boring machines. Current drill and blast methods are cyclic and there- fore limited in speed of operation. Boring machines are limited to moderately hard rock due to bearing and cutter wear. The recent development of ANFO, which has reduced blasting costs markedly, was largely fortuitous because of the method of manufacturing AN prills. New slurries and fluid explosives are easy to load and have high energy-pressure characteristics.

Jan 1, 1971

By C. S. Chang

Replacement of active groups in corn starch, as shown by results of the starch derivatives tested, impairs rather than improves the value of corn starch as a selective iron oxide depressant. Increased ability to depress iron oxides is generally accompanied by a parallel ability to depress quartz. PEARL starch, a corn starch prepared with a minimum of alteration, is a good selective depressant for iron oxide minerals.' From what is known of the complex chemistry of corn starch, there is evidence that it consists of a mixture of saturated giant polymeric molecules, both straight and branch-chained, the constituents consisting of glucose units with hydroxyl radicals as active or polar groups. To add to the existing knowledge of the chemistry of the flotation process, it is desirable to ascertain the effects on the corn starch as an iron oxide depres-

Jan 1, 1955

By G. F. Ziesing, E. F. Loros, T. J. Smolik

The Golden Sunlight mine began full-scale operations in February 1983 with a conventional open-pit mine supplying 4536 t/d (5000 stpd) of milling ore. After crushing and grinding, the ore is leached with cyanide solution in large agitation tanks. Soluble gold values are removed from the sand portion of the leached ore with five stages of countercurrent washing cyclones. After thickening of the cyclone-wash overflow slurry, the gold is recovered in activated carbon with a six-stage carbon-in-pulp circuit and a five-stage upflow carbon column circuit. Pressure stripping, carbon reactivation, electrowinning, and refining complete the gold recovery process.

Jan 1, 1985

Eckley B. Coxe, Drifton, Pa.: Anthracite coal differs from other fuels in its greater solidity. It does not burn like coke or wood, or like bituminous and coking coals, which become more or less spongy when heated, so that combustion can take place to some

Jan 1, 1892

By John Edgar, Eugene P. Pfleider

Breakage of rock in mining operations as a part of the overall comminution process is examined. Examples of blasting practice are examined, and the energy expended is related to the comminution work accomplished. Costs for the comminution effected are examined, and an attempt is made to evaluate overall mining practice to determine the range of incremental costs for breaking the ore to a finer size in the mining step.

Jan 1, 1973

The Tooele plant is situated at the mouth of Pine Canyon, five miles northeast of Tooele City. The site forms one terminus of the Tooele Valley railway, which runs southwest through Tooele City to Warner, a station on the Los Angeles and Salt Lake Railroad, thirty-five miles southwest of Salt Lake City. An aerial tramway, four miles in length, crosses the Oquirrh mountains and connects the plant with the Bingham district. The plant consists of a lead-zinc flotation concentrator, lead smelter and copper smelter.

Jan 1, 1925

By Robert A. Lothrop, Richard B. Porter, Robert P. Porter

Changes became necessary in dredging methods employed in Idaho through passage of the Dredge Mining Protective Act (1954). Among other provisions, the law requires dredge operators to construct settling ponds of sufficient capacity and character to reasonably clarify the water used in the mining process before such water is discharged into the stream. Porter Bros. Corp., a placer mining company with many years operating experience in Oregon and Montana, became interested in strategic mineral placers in Idaho in 1950 when it was learned that prospectors had discovered a radioactive mineral deposit in Bear Valley Creek, 95 miles northeast of Boise. The company acquired mining leases and proceeded with exploration and development work on the property. After extensive research had resulted in the determination of successful separation processes, contracts were negotiated with the federal government and deliveries of columbium-tantalum and uranium concentrates commenced in 1956.

Jan 5, 1960

By William M. Huang, T. Carl Shelton

There are undoubtedly many factors that affect the emission of gas from coal but the permeability of coal to gas flow would seem to be fundamental. However, there is very little information on coal permeability to gas flow available in the U.S. at the present time, despite the fact that such knowledge would appear to be significant in any degasification effort. Studies made recently in the mining engineering laboratories at Virginia Polytechnic Institute have determined values of permeability on one-inch cubes of selected coals. COAL PERMEABILITY The permeability values given in this paper are based on adaptations of Darcy's Law formulated by Henry Darcy in 1856 from experiments with fluid flow in porous media.' Using air as the gaseous fiuid, they were obtained by employing similar methods as are used to determine the permeability of petroleum and gas reservoir rock specimens.

Jan 5, 1962

By B. Wilshire, W. J. Evans

The high-temperature creep properties of nickel, zinc, and iron have been determined over a range of stresses. The creep strain, E, was found to vary with time, t, as: where e0 is the instantaneous strain on loading, ET the total transient creep strain, $ the steady creep rate, and m is a constant relating to the rate of exhaustion of transient creep. Deviations from this relationship occurred during the initial 10 to 15 pct of the transient stage. These deviations result in the initial creep rate, go, calculated as (m . ET + es), being considerably lower than those obtained by measurements on the creep curve. For all materials, the initial creep rate, the constant m, and the duration of transient creep are all related to the steady creep rate. These relationships suggest that transient and steady-state creep should not be regarded as distinct stages.

Jan 1, 1969

IT is not necessary to enter into a long discussion of ordinary bells, because every master carpenter or blacksmith knows how to make those levers with a crossbar that are called storks. This is nothing other than a board that has a thick and heavy head and looks more like a dolphin than a bird. This has a long tail in the form of a handle so that it makes a more powerful lever. As can be seen in every bell tower and other place where there are bells, it has, crosswise above the point where the cannon of the bell is fitted and fastened in, an iron bar which is arched and which has its two ends turned horizontally. These are made round so that they may turn easily when they are held by two steel rings or in two metal grooves or on glass pillows. In this, the more the transverse rod is arched,

Jan 1, 1942