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By L. Alan Weakly

Abstract-The Bureau of Mines has pursued a program of research on mine illumination that has defined the coal miner's illumination needs. St. Joe Minerals Corporation, recognizing the need for improving the illumination of the working places in their mines, entered into a cooperative research agreement with the Bureau of Mines to utilize the Bureau's expertise in this field. Some similarity in the environment, in which coal and hard rock miners work, has allowed the application of developed coal mine illumination technology and equipment to be utilized in hard rock, room and pillar mines.

Jan 6, 1978

By Sam F. Harrison

The National Board of Boiler and Pressure Vessel Inspectors again sends out this recommendation: If you have an air compressor that is mounted directly on the air tank, get it off. Characteristically, small- to intermediate-sized air receivers are thin-walled vessels, and as such are prone to failure when subjected to external loading. Many of these vessels, if not a great majority, are bought by a distributor of air compressor systems, who provides the compressor, motor, switchgear and other accoutrements-all of which are very frequently mounted on a base which is then welded to the shell of the receiver. These welds at the points of attachment transmit external loading to the tank in the form of weight and vibration, frequently resulting in stress-induced cracks.

Jan 3, 1978

Despite the uncertain political situation in Katanga, copper and cobalt mining and metallurgical operations of Union Miniere du Haut-Katanga were normal at the time of this writing. In fact operations continued normal after Congo independence on June 30, 1960, with copper and zinc production for that year being slightly higher than in 1959. United Nations military operations from September to December 1961 resulted in death, shutdowns and damage to company persons and installations. Nevertheless, results for that year were only slightly off normal production. Moise Tshombe delared Katanga a separate state after Congo independence. Although there has been tribal unrest, the new State has enjoyed relative calm and normal industry by comparison with other parts of the Congo as a result of the firm hand of Moise Tshombe's government and the continued presence of Belgian officials and technicians.

Jan 12, 1962

By B. Barlin, G. A. L. Smith, I. J. I. Delaney

A method was developed to quantify the three mineral species, sphalerite, galena, and pyrite in seven concentrator products. Intermineral effects were studied and a statistical analysis was undertaken to assess the accuracy and reproducibility of the method. The method is both rapid and suitable for plant control purposes. Furthermore, it requires only semiskilled laboratory personnel to carry out all the analyses.

Jan 1, 1976

By Daniel T. Hegyan, Thomas B. Zugates

Continuous vacuum disk filters are increasingly being used to filter refuse from the fine-coal washing circuits as it becomes important to close the water circuits and eliminate sludge holding ponds. This paper discusses our past experience filtering refuse, effects of solids concentration in the filter feed, use of polymer flocculation aids, effect of flocculation devices, and effects of particle size and ash content on the filtration rate. Detailed tests were performed on existing installations utilizing coal refuse filters to determine optimum flocculant dosage, solids concentration, and disk rotation speed to form a dischargeable cake. Information was also obtained showing effect of flocculant addition on the moisture of the filter cake.

Jan 1, 1977

By Edwin T. Wood

THE term blending as used herein refers to the mixing of ores assaying more than 0.20 pct U3O8 with low grade material assaying less than 0.20 pct U3O8. Such blending when properly understood and controlled will produce more total dollars of profit from many mining ventures. The question whether or not to blend is particularly vexing when an orebody is surrounded by an envelope of low grade material or separate tonnages of low grade exist which could be extracted coincident with the higher grade ores. Should any, all or part of this low grade be mined? If so, in what proportion and what is the limiting assay of the low grade material?

Jan 7, 1958

PERSONAL (Members are urged to send in for this column any notes of interest concerning themselves or their fellow-members.) Members and guests who registered at Institute headquarters during. the period May 10 to June 10, 1915: Robert M. Keeney, Somersville, Conn. C. A. Moffett, Birmingham, Ala. Emilio Mosonyi, San Salvador, C. A: A. W. G. Wilson, Ottawa, Canada. Junjiro Nagazumi, Fukuoka, Japan. G. H. Glover, Jr., Short Hills, N. J. Francis R. Pyne, Elizabeth, N. J. R. W. Brock, Vancouver, B. C. F. C. Alsdorf, Los Angeles, Cal. J. L. W. Birkinbine, Philadelphia, Pa. W. J. Loring, London, England. Roy H. Allen, Jamesburg, N. J. R. A. Bull, Granite City; 111. Francis Andrew Thomson received the degree of Master of Science from the Colorado School of Mines at the recent commencement exercises. The subject of his thesis was Stamp Milling and Cyaniding.

Jan 7, 1915

By Koehler S. Stout

At today's mineral prices, unproductive or low productive work in any underground mine must be kept at a minimum to insure a profit. Improper level and raise spacing can be one of the contributing factors to high production costs, and little can be done to reduce these costs after the spacing interval has been chosen. The objective in selecting level spacing is to find the most desirable interval which produces ore at the least cost per ton while still operating within the highest margins of safety and efficiency to the workmen. In addition, maximum possible recovery of ore under the conditions must be attained.

Jan 11, 1962

By Cleland N. Conwell

Reclaiming mined land in northern regions is less difficult than reclaiming semiarid lands. In 1972, the Usibelli coal mine near Healy, Alaska, initiated experimental plots to determine the proper grasses and amounts of fertilizer. The following spring, approximately 1600 acres of land disturbed by mining were seeded by low-flying aircraft. The reclamation project was evaluated by the State of Alaska and has been adjudged successful. The information gained is being used in reviewing prospecting permits and granting coal leases on state lands.

Jan 1, 1977

By J. W. Moody

The first Rodpeb mill ever built and placed in full scale successful operation went onstream in mid- 1960 at Marquette Cement Manufacturing Co.'s newly modernized portland cement production plant at Nashville, Tenn. It replaced a third stage of fine crushing and two 7x22-ft Compeb mills in the wet raw slurry grinding department. The Rodpeb mill at Nashville is similar in appearance to a Compeb mill but is larger. The mill, which operates in open circuit, is 9 ft in diameter and 38 ft long. The rod compartment is 12 ft long, with the rods being 11.5 ft in length and ranging in diameter from 4 in. down to about 1 in. The weight of the rod charge is 100,000 lb. The liners of the rod compartment are of the Lorain design.

Jan 4, 1963

By Duk-Won Park, Syd S. Peng

INTRODUCTION More than five years have elapsed since the first shortwall panel was installed in a US mine in 1972. By the latest count, 11 mines have tried the shortwall method on 34 panels. Potentially, the shortwall method (see Figure 1) offers the combined advantages of longwall and continuous mlning. But just like any other mining method, shortwall is not a panacea. It is only applicable under a set of stringent conditions. Coal operators at eight of the eleven mines are satisfied with shortwall mining, though there are only five mines presently producing coal from shortwall panels.

Jan 1, 1981

By H. W. Hitzrot, R. A. Limons, L. V. Fegan

The authors have developed and tested a new method for measuring pellet-bed temperatures in the traveling-grate or the shaft furnace. This method-using silver-palladium alloy wires as indicators-is less costly and less time-consuming than existing methods. Silver palladium wires, having specific melting points in the 2000° to 2500°F range, are enclosed in ceramic capsules. Each capsule is placed in a nichrome wire basket filled with a sample of green pellets, the baskets being the means for recovering the capsule after firing. After the encapsulated wires have been exposed to the firing cycle, the alloy wires are examined to determine the maximum temperatures attained by the pellet sample. This gives accurate, rapid determinations of maximum temperatures attained during pellet induration in either the traveling-grate or shaft furnace.

Jan 6, 1965

The primary purpose of the Institute is to advance the technologic and engineering arts embraced by it through interchange of knowledge. This can best be done by the presentation and discussion of technical papers by its members. Short practical papers are especially welcome. An author should always satisfy himself that his material is of a quality that will be a credit to him and to the Institute. The preparation of a good paper frequently leads to a reorientation of the author's thoughts, and publication contributes much to the professional standing of the author. Members are urged to submit papers presenting the results of their work. Attention to the following suggestions will greatly further the prompt and efficient handling of manuscripts.

Jan 1, 1944

COMMITTEE IN CHARGE SPENCER PENROSE, Chairman A. E. CARLTON, Chairman Finance Committee GEORGE M. -TAYLOR, Vice-chairman. J. DAMSON HAWKINS, Secretary DENVER COLORADO SPRINGS Finance Finance T. B. STEARNS A. E. CARLTON RICHARD A. PARKER SPENCER PENROSE T. B. BURBRIDGE GEORGE M. TAYLOR A. L. BLOOMFIELD, Treasurer Arrangement Registration DAVE G. MILLER LOREN C. LENNOX FRANK BULKLEY HORACE F. LUNT GEO. E. COLLINS J. M. TIPPETT Entertainment Arrangement and Entertainment F. H. BOSTWICK GEORGE M. TAYLOR F. E. SHEPARD J. D. HAWKINS HOWLAND BANCROFT A. E. CARLTON B. P. MORSE A. L. BLOOMFIELD J. G. PERRY THOMAS B. CRONE E. P. ARTHUR ETIENNE A. RITTER CRIPPLE CREEK PUEBLO THOMAS B. CRONE J. F. WELBORN E. B. ARTHUR H. B. CARPENTER N. S. GREENSFELDER L. B. EAMES A. E. CARLTON F. ROBINSON B. F. HILL J. G. WILLIS

Jan 8, 1918

Manganese ore from the Black Rock, Kramer, and Black Jack mines in Tooele and Jaub Counties, Utah, are of acceptable grade, the U. S. Bureau of Mines has announced. Payment of a premium price of 252¢ per lb to the Copper Range Co., of Michigan for the output of its White Pine mine, has been agreed to by the DMPA. The contract will be limited to $28.6 million worth of copper. The agreement follows an RFC loan grant of $57 million to bring the White Pine property into production within three years. Increases of 5 to 6 cents over the Lake copper ceilings have been granted to the Calumet & Helca Consolidated Copper Co., for operation of "high cost" deposits, according to Jess Larson, DMPA administrator. Mr. Larson expects the move to add about one million lb of copper per month to the supply. The agreement can be cancelled on 60 days notice and is terminated automatically in the event copper ceilings are removed.

Jan 1, 1952

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 A. U. Seybolt, F. J. Norton

A standard technique for heat treating small metallurgical samples where no appreciable contamination from the atmosphere can be tolerated is that of sealing small samples in evacuated fused-silica tubes. Since vitreous silica is relatively impervious to diffusion of gases, even at temperatures approaching the devitrification range, around 1100°C, this simple procedure has been very widely adopted as a standard technique in metallurgical research. Many workers have recognized that, with metals of fairly high reactivity, insulation from direct contact with the SiOz envelope is desirable in order to avoid displacement reactions of the type M + SOz-- MOz + Si(in M). It is not so generally known, however, that the 'rate of permeation of oxygen from the air through the SiOz enclosure at tem-

Jan 1, 1964

Jan 1, 1914

By Ralph E. Wood

X-ray fluorescence analysis can be profitably applied in the mineral industry by improving evaluation and control analyses, while offering lower cost and greater speed than conventional methods. Chemical analyses are not only a major item of cost in exploration and mining, as well as in milling and chemical treatment, but often cause evaluation and control of processing steps to lag behind operations. In the fields of geology and mining, the X-ray technique can be employed without destroying samples and, if necessary, specimens can be analyzed and then used, unchanged, in other evaluation techniques. Results are quickly made available for decisions on progress of exploration or sorting of waste and ore.

Jan 6, 1959

By L. M. Clarebrough, A. K. Head, G. W. West, M. E. Hargreaves

RECENTLY Welber and Webelerl reported that during the annealing of fatigued copper no energy was released, but that energy was absorbed in the range of temperature 250" to 400°C. In view of the fact that strain hardening occurs during the fatigue of copper, this result was surprising and it seemed desirable to check the measurements. This note describes measurements made by a different technique which indicates that energy is stored during the fatigue of copper. Two test bars with gage length ¾ in. in diameter and 6 in. long were machined from OFHC copper and annealed in vacuum for 1 hr at 600°C. These were fatigued to fracture in an Avery pulsator at a frequency of 2000 cycles per min. The first specimen fractured after 0.25x10 cycles under a push-pull

Jan 1, 1956