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By Harold M. Mooney

WHEN apparent resistivity data are taken with the symmetrical Wenner 4-electrode spread, a fixed center position is used and readings are taken for values of electrode separation. Basic data consist of apparent resistivity plotted against separation of adjacent electrodes. The interpreter attempts to infer geologic structure, such as the depth to discontinuities and the nature of subsurface earth materials. An earlier paper1 described methods for interpreting resistivity data. All of these involve a severe assumption, namely that the earth in the region of interest consists of horizontal layers, electrically homogeneous and isotropic. The actual earth never satisfies this assumption exactly and may deviate from it so much that none of the above methods can be applied. Attempts in three directions have been made to modify the assumption so that it approaches known geologic complexity more closely.

Jan 12, 1954

By Joseph M. Chelini

A cash-flow factor is any figure acquired in an evaluation that effects the cash flow potential of an eventual operation. Table I is a list of some of these cash-flow factors. There are more, such as, the payments and penalties in a smelter schedule if the concentrate would be sent to a smelter. During an evaluation it is necessary to maintain a two-way flow of communication between the evaluation people and financing people. To accomplish this, it is necessary to translate the vocabulary of the evaluating people into the vocabulary of the financing people, or geologic and engineering jargon into dollars and cents. This is done by cash-flow studies in which cash-flow factors are input, which when logically manipulated using accepted rules and procedures of accounting, provide an output in dollars and cents.

Jan 5, 1972

The Institute conducts jointly with the American Society of Civil Engineers, American Society of Mechanical Engineers and American Institute of Electrical Engineers, certain activities as listed below, and is joint owner with them of certain properties. United Engineering Trustees, Inc. When Mr. Carnegie made his gift which made possible a home for the engineering societies, a separate corporation was organized to act as a holding company and to manage the common property. This was long known as the United Engineering Society, but the name has now hen changed to one which more nearly reflects the real function of the corporation. It holds title to the Engineering Societies Building and to various funds placed in its charge and is managed by a Board of Trustees, of which three are chosen by each of the four societies, American Institute of Mining and Metallurgical

Jan 1, 1932

By Stuart M. Buck

THE term "splint" seems to have been adopted to describe the fracture of the hard bituminous coals of West Virginia. It is not a scientific name,, but rather a trade term, and does not indicate a correspondence with English splint. At present it is a popular word, and is very loosely applied to coals of various qualities, in the desire to improve their sale. The Kanawha splint is distinguished by its hardness, dull lustre, coarse fibrous structure, its purity, and especially its resistance to atmospheric influence. It kindles very readily, burns with a bright flame, but does not cake, so that a lump when half consumed, may be broken by a slight blow in its plane of cleavage, though 'it will resist a' strong blow in any other direction. I have seen pieces that have been exposed to frost and sun

Jan 1, 1882

By Stuart M. Buck

The term "splint" seems to have been adopted to describe the fracture of the hard bituminous coals of West Virginia. It is not a scientific name, but rather a trade term, and does not indicate a correspondence with English splint. At present it is a popular word, and is very loosely applied to coals of various qualities, in the desire & improve their sale. The Kanawha splint is distinguished by its hardness, dull lustre, coarse fibrous structure, its purity, and especially its resistance to atmospheric influence. It kindles very readily, burns with a bright flame, but does not cake, so that a lump when half consumed, may be broken by a slight blow in its plane of cleavage, though it will resist a strong blow in any other direction. I have seen pieces that have been exposed to frost and sun

Jan 1, 1882

New Device Eliminates Blasting in Coal A non-explosive device developed by duPont utilizes the high pressure of a gas generated inside a steel tube which is inserted in a hole drilled in a coal seam to break down the face of coal. Chemical reaction is started by an electric current which produces heat to initiate the action. The same heat destroys the starter wire as soon as electric current is no longer needed. The tube containing the chemical is closed at the outer end by a plug with electrical connections, and at the other with a disk that is ruptured by the compressed gases formed. When the gas has been liberated in sufficient quantities to create a desired pressure the disk breaks and the released gas breaks down the coal face. The new device is called a Chemechol.

Jan 10, 1951

The fall meeting of the Coal Division t was held at Pittsburgh, Oct 21-22, with the William Penn Hotel as headquarters The registration totalled 168 Secretary Parsons, George Otis Smith and J T Breunich were the official representatives from Institute headquarters Eighteen papers were presented There were five sessions altogether Monday morning and afternoon were devoted to papers on miscellaneous subjects, on Thursday morning there were two sessions, one on combustion of coal, the other on miming subjects, and on Thursday afternoon the outstanding feature of the meeting occurred when the members of the Division met in the Cathedral of Learning, University of Pittsburgh, to hear the prize-winning papers read by J F Bottomley, of Harrisburg, I11 , and William Bellano, of Crested Butte, Colo All the students of the School of Mines at the University attended this session The informal

Jan 1, 1937

By Robert W. Coughlin

Pulverized coal has been introduced at the anode where it is oxidized during the electrowinning of metals from their aqueous solutions This substitutes an electrochemical reaction between coal and water for the usual oxygen-evolving half-cell reaction at the anode, with the result that overall cell potential is significantly lowered and the consumption of electrical energy is correspondingly reduced. Experimental results are reported for electrowinning copper as an example of this novel modification of the electrowinning process in this example, the use of coal lowered the consumption of electricity by two-thirds of the requirement of the conventional process When the potential electrical energy of the coal consumed is considered the new, coal-assisted process consumes about 45% less energy, and the energy costs (combined costs of coal and electricity) are reduced by about 50%.

Jan 1, 1981

By C. W. Merrill

The cyanide process in the United States, notwithstanding numerous failures made under the direction of the owners of the patent-rights, and others, has now passed its experimeiital stage, and can, undoubtedly, be made successful when intelligently applied to suitable material. Much, however, remains to be known as to the exact conditions under which this process is applicable to the treatment of gold-bearing ores. If the owners of the patent-rights in this country have ever scientifically investigated the matter, they have never published any valuable informatioil on the subject. Other parties who are now using the process (often independently of the patentees), have nothing to gain by publishing their experience; and, moreover, many of the chemical reactions described in the text-books refer to the use of solutions of potassium cyanide many times stronger than are used in the metallurgical process.

Jan 1, 1896

By Richard K. Thorpe, Gordon D. Anderson, Merle E. Hanson, Ronald J. Shaffer

The propagation of pressurized fractures across a frictional interface is discussed, with emphasis on the case where an offset, or step, in the crack is produced. Theoretically, the steps can occur at regions of reduced shear strength along the interface. As a fracture is propagated toward a weak zone, extensional strain is concentrated at the edges of the zone where higher shear stresses can be sustained. Thus, when the fracture intersects the weak zone, it can be reinitiated at some small distance away on the opposite wall of the interface. The phenomenon has been studied through numerical modeling and laboratory experiments of the hydraulic fracturing process. Field observation of natural step cracks indicates that the mechanism is applicable to the genesis of jointing patterns in rock. Such features should not be confused, therefore, with steps caused by shear displacement of an interface.

Jan 1, 1982

By R. W. Leonard

A method of accurately determining the value of gold-bearing ores and gravels with a compact field-outfit is much desired by prospectors, especially when the work lies in a district far removed from railways or good wagon-roads. We are all familiar with the fire-assay of gold-ores, and fully recognize its accuracy and value; but only those who have tried to determine the value of a gold-bearing vein as a commercial venture, from fire-assays of selected samples, know how misleading is the information thus obtained, however carefully and honestly the samples may be selected. The reasons are that, for the fire-assay a very small portion of ore is treated (rarely more than six assay-tons, or a little over one-third of a pound), and a minute particle of the precious

Jan 1, 1896

NOTHING makes the run-of-the-hall Congressman feel quite so secure as to be on an investigating committee. It's sure fire publicity for one thing and is a convenient excuse for absence from Congressional sessions when controversial issues are being balloted. The minerals procurement program has just had a thorough investigation by Congressmen of the House Interior and Insular Affairs Committee who heard valuable testimony from men like John D. Morgan, director of materials procurement, DPA. He listed over 40 government agencies concerned with mineral affairs. Testimony disclosed the justification for many of the agencies but Congressmen and mine operators have been regarding the defense minerals program in the same light as did the mining student who remarked to the descriptive geometry prof "it's not the intrinsic difficulty of the problem which gives me trouble; it's the multiplicity of detail."

Jan 9, 1951

By Jerry L. Taylor

Utah Power & Light Company is an electric utility serving approximately 1.8 million people in Utah, Idaho, and waning. In order to supply coal to fuel power plants, Utah Power & Light awns three mines in central Utah. Planning for these mines is aided by a computer program developed by the staff mining engineers. This program, when supplied with the pertinent seam and mining configuration data, calculates the time to mine each section. This allows the planning engineer to estimate accurately the time required to extract pillar sections or develop longwall panels. The program's greatest benefit, however, is its ability to allow the engineer to examine quickly, different combinations of possible mine layouts to determine the most efficient plan. Computer aided mine planning has been used at Utah Power & Light Company since 1979, and has significantly improved the accuracy and quality of mine planning.

Jan 1, 1983

By Michael D. Loy

While the coal industry in general has been slow in accepting automation, the last few years have seen a myriad of products developed by the private sector. These packages run the full gamut from sophisticated geological information systems to line entry discounted cash flow analyses. This paper is an attempt to unravel the confusion that may exist about mining software. Discussions will highlight major differences between software products (such as block vs. grid models, prefeasibility programs vs. Monte Carlo analyses), briefly discuss known vendors, list known package features and touch on hardware requirements. The paper also focuses on the costs of automation (both software and hardware), possible trade-offs, advantages to in-house systems (vs. timesharing), a recommended review/selection process (including suggested RFP format), a test case procedure, when to bring in a consultant, and staffing considerations.

Jan 1, 1983

By W. H. Adams

At the present time all the larger and better chemical works of Europe and the United States have introduced, as essential factors in the economical manufacture of sulphuric acid, both Glover towers and Gay-Lussac absorbing columns. The clear exposition of facts given by Bode and Lunge in their very valuable technical contributions since 1870 has slowly but surely brought about radical changes from the old methods of manufacture ; but while the Gay-Lussac column has been known since 1827 and the Glover tower was originated in 1869, yet no theoretical treatise covering the subject fully was given to the world until 1876, when the various contrivances for demonstrating nitrous vitriol were described and criticized by Fr, Bode in a paper "On the Glover Tower" which obtained the great prize of the Berlin Society for the Promotion of Industry.*

Jan 1, 1887

By O. W. Walvoord

A Definition: An ore feeder is a mechanical device that, by virtue of its motion, causes ore to be supplied or carried forward at a desired metered rate to other milling equipment. From the viewpoint of economics there can be little question, even for small tonnage operations, as to the advisability of using mechanical feeders in the place of manual labor. Only a few short years ago, it was common practice to employ crusher men for the feeding of crushers, thus eliminating the capital expenditures required for mechanical feeding equipment. Having been a crusher man in several instances, the author does not favor such practice. The high cost of labor today eliminates the crusher man, and feeders become an economical capital expenditure when considered against the importance of obtaining maximum production efficiency from all the machines in a process flowsheet.

Jan 2, 1955

By Bertrand Robinson

Epitomized, there have been no innovations recently in crushing, but in grinding the trend has been towards larger units under more automatic control with an increased use of autogenous grinding. Crushing Portability of primary crushers to "follow the face" reduces material handling costs. The top size of crusher feed still establishes the size of the crusher; the feed opening should be 1 1/2 times the size of the largest feed. The maximum size of crusher product is 1 ½ times the open scale setting of a jaw or gyratory crusher. Practice dictates use of scalping screens ahead of any type of crusher when the feed contains 25% or more of product size. If required capacity is under 600-700 tph economics favor a double toggle crusher or an impactor. For larger capacities the gyratory crusher is favored.

Jan 1, 1970

By David J. Dunn

At a time when mill availability is at a premium, production costs are rising, and lead time for mill liner casting is a year or more, mill liner design is an important factor in ore grinding. Testing and selection of the optimum liner profile for a given set of mill operating conditions can improve mill capacity, reduce liner wear rate, and lengthen liner life. The mill liner that grinds best, lasts the longest, and costs the least is a necessity for economic mill operation. After testing four mill liner profiles for 3.96 X 3.65-m (13 x 12-ft) overflow ball mills, Climax Molybdenum Co. found that an improved design increased mill tonnage by 2.72 t/h (3 stph) while reducing finish grind by 1.7% minus 100-mesh, reduced liner wear rate, and almost doubled liner life.

Jan 12, 1976

By H. C. Fiedler

SILICON-IRON strip with a cube-on-edge secondary recrystallization texture is made commercially as thin as 10 mils. With inclusions present to inhibit normal grain growth, a few grains, and these have the (110)[001] orientation, grow very large at the expense of the matrix grains. In the absence of inclusions, only normal grain growth occurs and the texture is not as strong as when it is developed by secondary recrystallization.1 Strip for use at frequencies of 400 cps and higher is made in thicknesses of 1, 2, and 4 mils by a process developed by Littmann.2 Attempts to develop a strong texture in these thin gages by the same methods as were used for the 10 mil and thicker strip were unsuccessful,2 and Littmann's solution to this problem was to cold roll the grain

Jan 1, 1963

By ElRoy Nelson

WATER provides to many mineral industries functions similar to those performed by money in the economic system. Water is a medium of exchange. It is also required in chemical reaction for cooling, for transfer of minerals, and for cleaning. To a great extent, water is also a raw material in almost every industrial operation; it becomes a component of the finished product. In the Rocky Mountain region, water is treated with a great deal of respect. There has not been enough of it when needed. Long ago storage facilities were planned and devised to assure a supply during periods of shortages. This comes from the history of the region in irrigation and mineral processing. Within this region the shovel was always the most lethal weapon used in settling disputes over the use or misuse of water.

Jan 10, 1954