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By G. D. Monk, W. C. Krumbein

THE relation between permeability and the size parameters of unconsolidated sand is approached by considering sands as logarithmic frequency distributions having the basic parameters mean size and standard deviation. Sieve separates were mixed in accordance with the normal logarithmic probability law, so that the mean and standard deviation could be varied at will. Experiments were conducted in which one parameter was kept fixed and the other varied; in this manner the dependence of permeability on the individual parameters was evaluated. It was found that permeability can be expressed as the product of a power function of the mean size and an exponential function of the standard deviation.

Jan 1, 1942

By D. B. Barker, D. C. Holloway, J. F. Cardenas-Garcia

Tround International Inc. is currently developing a hard rock drill that uses a salvo of three frangible projectiles to prefracture the rock ahead of a conventional tri-cone bit. This paper reports on a series of experiments conducted for Tround to study the fragmentation enhancement possible through the use of an optimally timed and spaced salvo of projectiles. In this study the complex three-dimensional problem was simplified to a two dimensional salvo impact problem in a transparent brittle plate of glass. The use of high speed photography and dynamic photoelasticity was then used to study the development of the impact damage zone and the various interactions of the stress waves.

Jan 1, 1982

By Finn Ouchterlony

A simple bilinear R-curve description of crack extension resistance is applied to the testing of sub-size rock core specimens. The K-curve consists of a linear sub-critical part and a flat post-critical part. Formulas for the apparent energy rate resistance quantities Gm, Jm, and [R] are developed. Experiments on notched cores of Ekeberg marble, Bohus granite, and Stripa granite are compared with these predictions. The R-curve model gives reasonable results for Gm -data but fails essentially to describe the Jm and [R]-data. Another model with a sharply increasing linear post-critical part could possibly account for the [R]-data, but direct R-curve measurements seem a better approach.

Jan 1, 1982

By J. F. Kemp

The death, on the 30th of May, 1896, at Paris, of the venerable Gabriel Auguste Daubrée, an honorary member of the Institute, recalls with emphasis the great value of his varied contributions to geology, mineralogy and hydrology. In fact, more and more as the years pass, and as attention is given to the obscure problems of metamorphism, of the development of joints, of slaty cleavage, of schistosity, of fault-systems, of the subterranean circulations of water, and of many other agencies which are often closely involved in the production of ore-bodies, the appreciation of his work increases, and quotations from his papers are made. Daubrde was born June 25, 1814, at Metz. After receiving

Jan 1, 1897

By J. C. Wynn

This paper outlines research conducted by the US Geological Survey on the geophysical signatures of chromite. Results of the chromite study highlight the importance of a laboratory research Phase (petrophysical and petrographic studies) at the beginning of work on a new commodity; a realistic ore deposition model to serve as a conceptual framework, and the necessity to continually test, refine, and modify it during the study; and indirect geologic/geochemical indicators, secondary associations, and the use of multiple physical properties. The keystone to the success of the study is frequent and substantive dialogue among geologists, geophysicists, and geochemists.

Jan 1, 1984

By Walter E. Heinrichs

Before covering the separate methods used in mining geophysics, it may be well to mention some current basic geophysical prospecting concepts. As in most fields, a better understanding and means of studying these fundamentals usually provides the more common improvements, rather than new principles being discovered. The relative detail and complexity of most mining geology often results in the use of geophysics in problems it cannot solve. On the other hand, suitable applications are often ignored or left unrecognized. To minimize this, it is important to consider geophysics as a phase, or additional tool, in geological or exploration engineering.

Aug 1, 1956

By Robert S. Schecter, Paul M. Bommer

This paper presents the development of and results from a computer model of in situ uranium leaching. This model uses a streamline-concentration balance approach and is useful with a wide range of reservoirs. It can be used with any type of well system, in a reservoir with or without boundaries, and with any form of descriptive kinetics. The model also includes the effects of dispersion and consumption of oxidant by minerals other than uranium. The effects of areal sweep, variable uranium concentrations, variable permeability, and the presence of oxidant consumers on uranium production are shown and discussed.

Jan 1, 1979

It took the US coal industry 55 years to increase domestic coal production by about 11%-from 568 million tpy in 1920 to today's level of about 630 million tpy. With such a growth record, it would take a few hundred years to double coal production. FEA planners think that it can be doubled in 10 years. "With all the obstacles continuously imposed on coal, the industry's real problem is not growth but survival," says Ray Albrechtsen, board chairman of Mountain States Resources Corp., and "we should consider ourselves lucky if, by 1985, the coal industry won't have been legislated and regulated out of existence."

Jan 5, 1975

By J. E. Lawver, G. L. Samsel

The success of many mineral dressing processes, including froth flotation and electrical concentration, depends largely on knowledge of physical and chemical structures of the mineral surfaces involved. As a general rule solids have surface layers, usually invisible by optical tests, that differ from the substratum. To the mineral engineer, therefore, a knowledge of the surface structures of minerals is of paramount importance. During the past decade one of the most powerful tools in the study of froth flotation mechanisms has been the use of radioactive tracers, but this technique usually cannot give definite information regarding the chemical changes that may or may not have occurred at the surface.

Jan 5, 1959

By A. B. Parsons

When the Seeley W. Mudd Memorial Fund was established in. 1929 the donors mentioned certain types of projects to which preference might be given in selecting those to he financed by the income from the Fund. One suggestion. was that the projects "be of particular benefit to young engineers." This modest little book meets this specification most aptly. It seeks to guide the engineer-particularly the young one-with the least loss of time and effort to the most convenient source of authentic information regarding any topic in which he may at the moment be interested. Knowing the best place to find the literature on a subject is almost as valuable-and far more practicable-than maintaining a library of one's own large enough to provide the information.

Jan 1, 1933

By E. B. Jensen, C. E. Doane, J. F. Pirozzoli

Results of an extensive one-year test of a nonelectric explosives detonating system led to the mine-wide adoption of this system in early 1978. Since that time, further experience with nonelectric initiation has verified the earlier results, which include the following benefits: Electrical insensitivity Improved productivity Cost effectiveness High reliability While electric blasting caps still experience a limited we restricted to trunkline initiation, all heading rounds as well as the bell, undercut, boundary-cutoff, and raise blasting are detonated nonelectrically. The primary blasting agent used at the Henderson mine is AN/FO, and primers are typically one of the following products, depending on applications: PETN, semi-gelatin dynamite, or a nonnitroglycerin water-gel slurry

Jan 1, 1984

By James R. Aggson, John C. Curran

In a cooperative research effort, the US Bureau of Mines Denver Mining Research Center and the Pittston Co. investigated floor heave ground control problems that have plagued underground coal mining of the Beckley coalbed in southern West Virginia. Floor heave is accompanied by a redistribution of stresses and loads that are associated with underground openings, causing roof and pillar problems. The floor and roof analysis techniques that were used in the USBM/Pittston investigation may have a wide range of applicability in the mining industry. Recommended orientations and geometries for mining operations are directed at floor problems, but may also enhance roof stability.

Jan 1, 1980

By A. J. Opinsky

MANY investigators, in their discussions, have reasoned that the ductile-brittle transition in iron could be explained by the intrusion of cleavage into the normal slip process. The purpose of this note is to apply the laws of critical normal stress for cleavage and critical shear stress for slip to explain the orientation and temperature dependence of the ductile-brittle transition in body-centered cubic metals. It will be found that within a certain temperature range, single crystals tested in tension will cleave or slip, depending on their orientation. Some data recently appearing in the literature will be analyzed from this standpoint. For a single crystal with [uvw] parallel to the tensile axis, the resolved shear stress on the slip

Jan 1, 1954

J. M. TIPPETT? Colorado Springs, Co1o.-There are several points which offer ground for discussion, although the authors' indicated results leave small chance for argument. Under classification of the ores as they come to the mill, it will be noted that these are classified according to their lime contents. In previous years the classification was based upon sulfur contents, CaO not being considered; class A would be called the oxidized ore and class B the sulfides. Classification according to CaO is the first public indication that a decided change in the ore has necessitated improved methods of treatment. The very serious effect that CaO, even in small quantities, has upon extraction has been noted for some years.

Jan 11, 1918

By O. Saeki

Dolomite-fluxed pellets have been produced at Kakogawa Works, Kobe Steel, Ltd., since August, 1975. The pellets contain 5.5 % dolomite and have a basicity (CaO/Si02) of 1.3. By charging 30-50 % of dolomite-fluxed pellets into the two large blast furnaces at Kakogawa, a low fuel rate of 450 kg per ton of pellets has been achieved with better furnace permeability and gas utilization. Laboratory studies show that dolomite-fluxed pellets have excellent high temperature properties, and that their softening and melting-down temperatures are about 50°C higher than those of lime-fluxed pellets, and that reducibility at 1250°C is increased from 25 to 70 %.

Jan 1, 1977

Bellows Connector Fabricated of chemically inert Teflon, the new bellows type connector has many pipe line applications where vibration, expansion and electrolysis exist in the handling of corrosive liquids or gases and solvents. The new connector is electrically non-conductive, flexible even at 94°F and as strong as 480°F as at 70°F, according to the manufacturer. This bellows connector serves as a [ ] vibration dampener as well as an expansion joint and connects misaligned couplings and insulates flanges electrically. End flanges of the joint are French-type envelope gaskets made integral with the joint for easy assembly between companion flanges and a tight, leak-proof seal on installation. Circle No. 1

Jan 1, 1952

By H. A. Burgman

During in situ uranium mining using ammonium bicarbonate lixiviant, the ammonium exchanges with cations on the ore's clay. After mining is complete, the ammonium may desorb into post-leach ground water. For the particular ore studied, other elements (uranium and selenium) that are mobilized during the leaching process, have also been found in post-leach ground water. Laboratory column tests, used to simulate the leaching process, have shown that aluminum chloride can rapidly remove ammonium from the ore and, thus, greatly reduce the subsequent ammonium leakage level into ground water. The aluminum chloride has also been found to reduce the leakage levels of uranium and selenium. In addition, the aluminum chloride treatment produces a rapid increase in permeability.

Jan 1, 1985

By C. W. Ryan

THIS paper contains a brief sketch of the geology of soapstone in the Piedmont section of Virginia, in the southern portion of Nelson County; also a description of methods of prospecting, developing quarries, quarrying and and milling methods in that section. The paper is intended for those who have little information regarding soapstone; undoubtedly men of practical experience will find many points for criticism.

Jan 1, 1929

By Henry B. Estabrooks

As was true with many mining companies, the management of Tennessee Copper Co. followed with interest the successful application of AN-FO as an explosive in coal stripping, construction, open-pit mining, and finally in underground salt mines. Since Tennessee Copper's operations required about 1,250,000 lb of dynamite annually, the potential savings in explosives costs that could be realized by switching to AN-FO could not be ignored. From a cautious start, AN-FO is now being used for stoping, development work and secondary blasting in all mines of Tennessee Copper Co. AN-FO accounts for 80% of the explosives used in such work. Fragmentation, fumes, crew acceptance, and cost savings have been quite attractive without any decrease in safety.

Jan 11, 1962

By John Birkinbine

Forty years ago, when the first shipments of iron-ore were made from the Lake Superior region, the supply for the blastfurnaces active at that date was in most cases a local consideration ; the majority of the smelting-plants being close to the oremines. Of those which depended in whole or in part upon ores brought from distances greater than an economical wagonhaul, few obtained supplies by canal or railroad from points 50 miles removed. At the present time the ore-supply is a local consideration for but a small proportion of American blast-furnaces, and 700 miles or more separate a greater num-

Jan 1, 1898