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By R. L. Loofbourow, Roger V. Pierce

THE degree to which our mineral requirements are being met by mining leaner, more complex or more remote deposits is indicated by developments during 1953. Heavy capital investment, skilled technical advice, planning, and able execution are requirements for the typical venture. Producers, faced with rising costs and with softer prices, are seeking improved mining and recovery. Developments in production of iron ore are typical of the course being followed in metal and nonmetal mining. Iron ore development in the U. S. is concentrated on the spectacular work with Lake Superior taconite, while in Canada new production is expected from Labrador and output from Steep Rock, Algoma, and Newfoundland is being increased. Shipment of iron will soon be made from Venezuela.

Jan 2, 1954

By S. H. Williston

IT IS not often that bore hole surveys can be checked by actual civil engineering methods. A recent Arizona survey was checked by normal surveying methods and the comparison of the results should be of value to both oil and mining men. During the summer of 1948 the Phelps-Dodge Corporation, at its Copper Queen property near Bisbee, Ariz., drilled a 1245 ft, 8 in. diam, churn drill-hole in a mineralized area and cased part of it, intending to use it to transfer mill tailings for stope fill. The hole, as frequently occurs, was not straight, and, in endeavoring to locate the bottom in the underground workings, they found no evidence of the hole at the underground coordinates directly below the surface location.

Jan 10, 1950

By C. R. Kuzell

The Editor desires to call attention to the charts in the paper of the above title which were published in the August Bulletin on pages 2190 and 2191. It was impracticable to include in the Bulletin. charts of sufficient size to be used as working diagrams for the direct determination of operating values, but the Institute is prepared to furnish copies of these charts on a large-size scale, at a moderate cost, to those who desire to have them for this purpose. CORRECTIONS Page 2185, line 3. For "is accessory apparatus" read "in accessory. apparatus." Page 2188. Substitute for lines 11 and 12: Nitrogen, oxygen, carbon monoxide, Cp = 6.50 + 0.0010T Hydrogen, Cp = 6.50 + 0.0009T

Jan 9, 1914

By Rudolph G. Wuerker

The scarcity of values of tensile strength of rocks has been explained by the lack of successful testing procedures. In the case of mine rock a description is given' of the difficulties encountered in testing a cylindrical specimen, such as a core, by conventional methods. Over a period of years the following method has given definite and reproducible results with the weakest as well as with the strongest rocks. It does not completely supersede the use of cores with special fixtures but is a supplement in all cases where cores cannot be obtained, as from soft rocks, or in cases where it is less expensive to prepare test specimens by cutting them out of the rock instead of drilling cores.

Jan 2, 1955

By I. Sheinhartz, H. M. McCullough

DURING the course of a lubrication study in relation to the compacting of metal powders, it became desirable to measure the thickness of sprayed graphite coatings on steel dies for hot pressing. The thickness of these lubricant coatings ranged between 0.0001 and 0.002 in. In their particular case, the authors were interested in a method for measuring the lubricant thickness on tapered die inserts having curved surfaces. The lubricant was sprayed on the inserts at an elevated temperature and it was desirable to measure the thickness as soon as possible after application. Various standard types of commercial equipment were tried. Most of the available devices operated on either a mechanical or magnetic principle. The mechanical devices, such as micrometers, dial indi-

Jan 1, 1956

By Robert C. Bates

Is the value of rock sealant on radon control destroyed by changes in barometric pressure? While an article by Dr. Gerald Schroeder in the June 1977 issue of MINING ENGINEERING suggests this, it should be noted this is not necessarily true as the ensuing discussion reveals. Before analyzing the data leading to Dr. Schroeder's conclusions, some comments on their source are needed. The figures were collected during a 1973 US Bureau of Mines test of radon barrier coatings in the Dakota uranium mine near Grants, N.M. Results of that test were reported by Franklin, et al 3,4 in 1975. The mine is essentially dry and ore occurrence is within a lightly cemented, porous medium-to coarse-grained sandstone of high permeability and radon emanation rate.

Jan 12, 1977

On October 20, 1964, in his Waldorf Towers suite, death came to Herbert Clark Hoover, 31st President of the United States. At his bedside were his two sons, Allan A. and Herbert Hoover, Jr. Many years of humanitarian and public service earned him the gratitude of millions here and abroad. The Nation mourned his death. For the mining fraternity and AIME in particular, the life of Herbert Hoover held particular meaning. During the years from 1895 to 1914 when he was actively engaged in mining, he conducted himself with extraordinary competence, energy and integrity. In the years following, when his qualities of administration and leadership literally forced him into the limelight, he continued his interest and lent his talents for the benefit of the engineering profession.

Jan 11, 1964

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

By A. F. Peterson

MUCH has been said and written about the engineer shortage. The mining branch in engineering has lagged during the past several decades. I can think of two institutions, formerly prominent in that field, that have discontinued this department and another that has branched from a purely mining school into various forms of engineering. Conversely, I do not recall any institutions that have added mining to their curricula. I believe that this action is in direct response to the demands of incoming students. But I also believe that while there is a specific demand for civil, mechanical, and electrical engineers in the highly complicated mining operations of today, our need for mining engineers capable of assuming top responsibility for mining operations is unchanged.

Jan 3, 1957

By C. Legrand

THE CHAIRMAN (B. B. GOTTSBERGER, Miami, Ariz.).-I think this experience of the Burro Mountain Copper Co. with oil engines as described by Mr. Legrand comes at a very opportune time. The fuel almost universally used in the mine power plants of the Southwest is oil. Additional economy in its use for power production is much to be desired. In the case of the Miami Copper Co., we have lately found it necessary to enlarge our power plant and, based on the experience of the Burro Mountain Copper Co., we have decided to install oil engines similar to those in their plant. I think it would be very interesting to have some discussion on this subject. Mr. Langton, did you tell me you had prepared some remarks?

Jan 12, 1916

By Alfred F. Brainerd

A few months since, Prof. Lawrence C. Johnson, of the U. 8. Survey, discovered in Mississippi large deposits of carbonate iron-ore, geologically located in the Claiborne formation of the Tertiary Epoch. These deposits are not pockets, but continuous layers or beds extending for miles, and can be located with certainty where they have not been removed by erosion. Upon examination, recently made by G. W. West, Birmingham, Ala., the largest deposits and highest grades of ore were found near Enterprise, Lauderdale county, and in Clark county, Miss. These beds measure from 10 to 18 feet in thickness, are superimposed upon a " burr rock," associated with green sand, and dip 30 feet to the mile southeast, at an altitude of 350 feet above sea-level, can be

Jan 1, 1888

By W. G. Cornwell, R. J. Hisshion

The development of a process for the treatment of telluride concentrates at Emperor Gold Mining Co. Vatukoula, is discussed. The concentrate is produced by flotation in cyanide solution immediately after milling. Two stages of cleaning are employed and a high-grade concentrate is produced usually containing more than 50% of the precious metal. The process developed in the first instance involved batch roasting followed by batch leaching in strong cyanide solution, recovering gold and silver only. The procedure currently employed is chemical oxidation of the tellurides using hypochlorite as the oxidant in a basic solution of a caustic soda and sodium carbonate. After oxidation the gold and silver are recovered by cyanidation. The residue is then leached with sodium sulfide and elemental tellurium precipitated with sodium sulfite.

Jan 1, 1977

By Otto W. Nuttli

The magnetic method of prospecting is well suited to determination of faulting in the basement rock. In addition to establishing the horizontal position of the fault, it often furnishes valuable information concerning the depth and amount of faulting. Consider a simple case of a vertical fault, represented in cross-section in Fig. 1. Let AA' represent the plane of observation (ordinarily the surface of the earth), and BB'B"B"' the upper surface of the basement. Assume that the sedimentary rocks are nonmagnetic, so that the magnetic susceptibility of the material above the basement is zero. Let k indicate the susceptibility of the basement rock, a- the density contrast between it and the neighboring sedimentary rocks, and t the amount of vertical displacement.

Jun 1, 1955

By F. N. Kissell, W. E. Schroeder, N. I. Jayaraman

This article discusses methods of improving airborne capture by conventional dust suppression systems. The work was performed in a full-scale plywood model of a mine entry with a wooden mockup of a Joy 12 CM continuous miner. Dust was introduced at the front of the entry, and water sprays knocked down part of the dust cloud. Sampling in the return air determined the percentage dust reduction. Based on the results, guidelines are offered for continuous miner spray systems to control dust. Empirical relations have been developed to determine the effect of changes in water spray pressure on air movement, dust knockdown, and pollutant concentrations in the face return. Nozzle selection and arrangement are discussed for high dust knockdown efficiencies.

Jan 1, 1986

By Kevin M. O’Connor

Examples are presented in which Time Domain Reflectometry (TDR) was employed to locate deformation in rock masses induced by mining. The first example involved monitoring the propogation of overburden fractures above a longwall coal panel and the second example involved the use of TDR to monitor rock mass deformation in the vicinity of a strip mine highwall. Rock mass deformation, strata separation and large block movement generated strains and failure along coaxial cables which were installed in drill holes and the TDR reflections generated by these strains and failures were monitored. Analysis of field data and a preliminary laboratory test indicate that it may be possible not only to locate rock mass movements but also to quantify these movements with TDR data.

Jan 1, 1984

By David S. Cahn

Pilot-plant and laboratory tests were made on blends of steel plant flue dust and portland cement to determine whether the flue dust could be pelletized for use as a source of iron in dry process cement manufacture. Strength and setting time results showed that an acceptable agglomerate can be made with a Type II portland cement binder. Abrasion-resistant and well-sized pellets were made in a horizontal drum, using a simulated closed circuit, with a binder content of 7.5% and a moisture content below 15%. Pellet quality was found to be relatively insensitive to changes in binder concentration above 5%. Simulations of stockpiling and weathering indicate that little difficulty would be encountered with use of the flue dust pellets in cement plants.

Jan 1, 1972

By Douglas W. Fuerstenau, Kalanadh V. S. Sastry

Mathematical considerations of green ball growth in a balling device by the mechanisms of layering new feed onto seed or recycle pellets are presented. An experimental procedure was developed for investigating the agglomerate growth by layering in which the addition of feed to a batch of seed pellets was made cyclically. Using this procedure, the layering growth mode under partial feed consumption and no seed generation conditions was investigated experimentally in a laboratory balling drum as a function of such operating variables as moisture content of the material, feed rate, and the size distribution of the seed pellets. The experimental results were analyzed in the context of the model equations and the layering growth constant was estimated as a function of the operating variables.

Jan 1, 1978

By D. Ott

Results of a research project on investment or lost wax casting will be presented. The project was concerned with various aspects of the process as they are typical for the production of jewellery from gold alloys. During these investigations testing methods for investment quality as well as for casting quality and the various process parameters were developed and charateristic defects as they occur in practice were traced back to their origin in the process. Investigated were various static casting and centrifugal casting methods in different atmospheres as well as vacuum casting in devices of different design. It was shown that independent of the method a close control of the many process parameters interfering with each other is essential for a quality casting.

Jan 1, 1984

I have attended these meetings, every year, since 1926 and have served on both the Pittsburgh and the National Executive Committees, so that I am fully aware - of the ruling of this organization regarding, "No Papers by Vendors". Since I am now classified as a VENDOR, I wish to express my sincere appreciation for the invitation to formally discuss these very interesting papers --all of which herald the coming of an entirely new era in the manufacture of quality steels. I also appreciate the references by Mr. Mosser and Dr. Swinkels to my first paper on the oxygen probe which was presented at the meeting of this group, here in Chicago, in 1966 and was subsequently published in the NOH Proceedings of that year. (1)

Jan 1, 1972

I SHALL proceed in this chapter to tell you about lead. Because this metal is overabundant in wateriness, and also because it has its other substances in poor elemental mixture, it is highly impure. It is called an imperfect, leprous, and little-fixed metal, which it clearly shows itself to be because of the ease of liquefying it and because it is easily converted largely into a dross that is almost earthy and also because of the stain that it leaves when it rubs against anything. Nevertheless, when we consider its effects, we judge it to be a metal that we are greatly indebted to. Even though Nature in creating us has put into our souls such a thirst and desire

Jan 1, 1942