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By J. L. Jernegan

IN the summer and fall of 1875, the author was present during a short smelting campaign at the Hall Valley works, and having had occasion to make a number of chemical analyses of the ores, fuel, and fluxes, deems that the results of the same, and also an account of the smelting operations, may be found of interest to members of the Institute. The mines and reduction works of the Hall Valley Silver-Lead Mining and Smelting Company (limited) are situated at Hall Valley, Park County, Colorado. The smelting works are located about half way from the mouth to the head of the above-named valley, and the mines high up on the mountains, near its head. The three principal mines of the company are the Whale, Leftwick, and Cold¬spring. They are all on different veins, running parallel to one another, with a general trend from southwest and northeast. The

Jan 1, 1877

By A. E. Outerbridge

It has been generally accepted as a fact that cast-iron, under the influence of repeated shocks, becomes brittle, and will finally break under a blow which otherwise it would have withstood. It will probably surprise metallurgists, therefore, to learn that experiment disproves the supposed fact, and establishes exactly its opposite. The result of about a thousand tests of bars of cast-iron of all grades, from the softest foundry-mixtures to the strongest car-wheel metal, enables me to assert with confidence that, within limits, cast-iron is materially strengthened by subjection to repeated shocks or blows. It is very well known that the usual process of annealing castings—such, for example, as car-wheels—increases their strength by relieving cooling-strains. But it is not well known (if known at all prior to this announcement) that the molecules of cast-iron are capable of movement—for they do not touch each other*—without the necessity of heating the casting, and that they can thus rearrange themselves in comfortable relation to their neighbors, and relieve the overcrowding near the surface of the casting. In more technical words, a molecular annealing may be accomplished at ordinary temperatures which will release the strains in the castings, precisely as does annealing by slow cooling in heated pits or ovens. A statement so surprising should not be made without sufficient data to establish its correctness beyond cavil, since it is contrary to former

Jan 1, 1897

R. L. Bullock (St. Joseph Lead Co., Bonne Terre, Mo.)— The progressive approach of The International Salt Co. as described by Mr. Ryon is certainly commendable as is his paper. St. Joseph Lead Co. has been shooting AN/FO in 13/8 to 1 1/4-in. holes for several months now (as of October 1960) on a trial basis. The results thus far obtained are excellent, but conclusive evidence at this date is premature. One point that he gave should interest even the most ardent skeptic. That is, they are getting a detonation of the 1 1/4-in. ANDO charges in 2 1/4-in. holes. In light of its low sensitivity and critical diameter, this would appear to be one of the worse conditions that one could expect in which to get proper detonation of AN/FO. It has been shown* that partial confinement sometimes decreases sensitivity of a column of explosive because the air space above the explosive becomes highly compressed and in turn compresses the explosive prior to passage of the detonation front. Apparently, this does not happen in their shooting and the poor explosive coupling caused by the 2 1/4-in. holes yields a minimum of overbreak and is an ideal condition for their back.

Jan 1, 1961

By Regis Chauvenet

I have been requested to sketch the iron resources of the State of Colorado, with reference both to existing, i.e., working mines, and to prospects more or less developed, but not contributing anything as yet to actual shipments. I should mention, though disliking apologies, that there is one region of the State which I believe to be important, and which has been assigned to me (with reference to its iron-deposits particularly) in the field-work of the present year for the School of Mines, which has not been systematically explored, and whose data are not in such shape as to enable me to give them in this paper. The region in question is Pitkin county and part of the adjoining country. Regarding the geological positions of the veins or deposits, they are sufficiently varied. In Boulder county there is a well-defined vein of titaniferous magnetite in ancient granite or gneiss, while in Park county there may be seen a deposit now under construction, as will later be described; when finished it will belong, let us say, to the post-quaternary. Between these, in Cambrian, Silurian, and Lower Carboniferous formations, are various deposits, and even the

Jan 1, 1890

By E. Nelson Fell

As this plant is the first ever erected in British Columbia for the treatment of tailings by the cyanide process, and as the ores of this, mine are of a character not unusual among gold-ores of this Province, it is probable that a description of the principal features of the plant, and of the methods employcd in its operation, may be interesting. These works were designed after a careful study of the process, in a small experimental plant, for a period of six months. During this period ten percolation-tests on charges of tailings of 1100 lbs. each, eight percolation-tests on similar charges of concentrates, and twenty-six tests 011 concentrates in a revolving barrel, were made, besides laboratory-experiments. The ore consists of a quartz gangue, containing a little lime and variable quantities of the sulphidcs of iron, lead and zinc. The following figures, giving the analyses of the ore before milling, and of the tailings after milling, which constituted the material to be cyanided, are based on the daily samples taken during February and March, 1901.

Jan 1, 1902

By R. F. Shurtz

This note calls attention to a contradiction in current eatistical theory and to corresponding difficulties in practice. These are significant concern in evaluating almost all ore deposits. The theoretical contradiction is that the commonly used spherical model for the semivariogram is not consistent with the usual definition of a "regionalized variable" as a mathematical function, the direct study of which "is excluded because its spatial variability is usually extremely erratic, with all kinds of discontinuities. . ." (Journel and Huijbregts, 1978). Specifically, this means a grade function that is too "rough" for interpolation to be useful. The practical difficulty is that the spherical semivariogram interprets the data upon which it is based in a manner that is, more often than not, demonstrably inconsistent with reality. This is attributable to the widely disregarded interaction between the sample pattern and the grade function. Each sample pattern "blurs" the grade function in its own particular way. It is as though the grade structure of the deposit were seen through a lens of poor resolution or reflected in a warped mirror, such as those found in amusement parks. The fitted spherical model embeds this sometimes dangerously blurred and distorted image in the Krige regression. A full analysis of these inconsistencies is to be presented later but, in the meantime, it seems urgent to communicate their effects so that those engaged in estimating ore reserves may be on guard. The spherical semivariogram has a sill and can be replaced by the corresponding covariogram. The equation of the spherical covariogram in normalized form, that is, variance and range both equal to one, is represented as: [ ]

Jan 1, 1984

By John W. Pack

At present the manufacture of metallic zinc, or spelter, in Missouri, is carried on only at the establishments located at Carondelet, or South St. Louis. Although the development of the industry has not yet reached that fulness which it has attained elsewhere in the United States, still the commanding advantages of position of these establishments are so evident that the prospective importance and magnitude of spelter manufacture in this State, and especially at this locality, can hardly be doubted. A study of the chemical and technical aspects of the business of these points cannot be without interest to the metallurgist as well as to the capitalist. I have endeavored to investigate, as far as was practicable, within the limits of a paper of this character, some of the problems connected with this industry, at the same time making a few comparisons of the results attained at some of the Carondelet works with those of other establishments with regard to which information could be obtained. In the prosecution of these studies I have been kindly aided by the managers of Carondelet establishments, and by Prof. Charles P. Williams, Director of Rolla School of Mines. To the latter I am especially indebted for assistance in regard to methods of analysis. To all these gentlemen I return my thanks for their valuable aid. Other sources of information will be duly credited in their proper places.

By L. W. Rowe, W. R. Opie

A brief history of TiCI, production and purification is given. Chlorinator feed materials for the production of TiCI4 are classified. The thermodynamics and kinetics of Ticl4 production by chlorination of TiO2 are discussed. Problems encountered in the chlorination and purification steps are outlined in detail. MOST of the current processes for the production of titanium metal require the use of TiC14 as a source of titanium values. This material can only be produced by a dry chlorination process, since it is immediately hydrolyzed in the presence of water. When pure, the tetrachloride is a colorless liquid boiling at 136°C. It fumes readily in moist air, reacting immediately with the moisture to form TiO, and HC1. History The tetrachloride was prepared as early as 1826 by DumasL who chlorinated a red hot mixture of carbon and TiO,. Since then, numerous other mixtures have been used including rutile, ilmenite, beneficiated ilmenites, titanium pigment, slags, and the various titanium metalloids such as TiN, TiCN, TiOC, and TiS2. S2Cl2, phosgene, and CC14 have been substituted for chlorine and CO has been used in place of carbon.

Jan 1, 1956

By G. W. Reimers, S. E. Khalafalla

A colloidal solution of a ferrimagnetic material, such as magnetite, in a liquid that is immiscible with and lighter than water is projected for use in selective separation of particles according to their density spectrum. Magnetic levitation forces can be created as an antigravity field when the fluid is properly placed in an inhomogeneous magnetic field. When the gradient of the magnetic field is directed downwards, the levitation force in the fluid will be in an upward direction to float sinking nonmagnetic bodies by counterbalancing their density mismatch with the magnetic fluid. Several nonmagnetic objects with densities ranging from 2.50 to 11.35-g cm' were made to float or submerge at will in a 0.96-g cm' density fluid placed in vertical magnetic field gradients ranging from 0.1 to 1 kilo-oersted cm-'. The magnetic levitation force in dyne cm' was found to vary linearly as a function of the object-fluid density mismatch with a slope equal to one g, the acceleration due to gravity.

Jan 1, 1974

By Saburo Shigeno, Kunzo Amano

As shafts and tunnels move deeper levels in underground mining, development planning becomes more complex. The most serious problem is the aggravation of environmental conditions due to the imposition of higher-than-natural temperatures upon exposed strata. Since such a problem is a potential hazard to health, safety, and production, the authors have developed a system of computer-derived ambient-air temperature data for every major point of an underground mine under a given set of conditions. This system is comprised of two subsystems: 1) Ventilation network analysis, 2) Estimation of air - current temperature. The former is based on the Hiramatsu-Oka method, an improvement of the Scott-Hinsley method. The Hiramatsu-Oka method allows fast convergence and consideration of various fan characteristics. The latter subsystem considers heat radiation from strata, and the humidity. In several tests conducted at Besshi and Sazare Mines of Japan, the computer-derived data correlated with actual conditions.

Jan 1, 1969

By Frank Firmstone

THE indicator cards shown herewith were taken by the writer in June, 1877, from the water-pressure blowing engine of the Longdale Iron Co., at Lucy Selina Furnace, Longdale, Virginia. A description of this engine with figures, and some indicator cards, was published by Washington Jones, Esq., Superintendent of the I. P. Morris Co.,* in the Journal of the Franklin Institute for May, 1877, to which those desiring a full account are referred, but for convenience the principal dimensions, etc., are given below. The machine consists of a pair of horizontal directacting blowing engines, connected at right angles to a common fly-wheel shaft. The blowing cylinders are 4 ft. diameter by 5 ft. stroke; the water cylinders were 18 in. diameter by 5 ft. stroke as built. Both water and blowing cylinders are double acting. The water valves are balanced piston valves, 18 in. diameter, moved directly by eccentrics on the fly-wheel- shaft. Great care was taken to have the areas of the ports and passages at least equal to the area of the working piston. The engine is set about 14 ft. above the tail-race, and the * The engine was built by the I. P. Morris Go., from drawings made by Messrs. Tuws and Hartman.

Jan 1, 1879

By E. F. Bailey, L. S. Birks

The effect of stress on the austenite to ferrite transformation in carbon steel was studied by X-ray diffraction techniques. Tensile stress was found to cause reorienta-tion of austenite above the transformation temperature, to accelerate equilibrium conditions at the transformation temperature, and to cause precipitation of large carbides at a critical value of stress. IN the past, a number of papers' have discussed the effect of stress on the austenite to martensite transformation at relatively low temperatures. In general, it has been shown that tensile stress induces some transformation at a given temperature, while compressive stress retards the transformation. Very little work has been reported on the effect of stress on the transformation from austenite to ferrite plus carbide near the A, point in steel. One of the few papers in the literature2 reports an increase in A1 of about 1°C in pearlitic steel upon the application of tensile stress. In this paper, the effect of tensile stress on eutec-toid steel at, and above, the A, point was studied in

Jan 1, 1956

By Emil Gathmann

Discussion of the paper of EMIL GATHMANN, presented at the San Francisco meeting September, 1915, and printed in Bulletin No. 104, August, 1915, pp. 1485 to 1492 H. W. LASH, Cleveland, 0.-I have found in practical experience that it is not objectionable to have some blow-holes in ingots. They enlarge during solidification and have a tendency to cause the steel to rise. If they are of fairly small size they weld up quite readily, especially where they are some distance from the surface. In that way a pipe, which is much more detrimental than a few small blow-holes, is prevented. There is a very great difference in the formation of blow-holes in steel. You get one condition in soft steel and entirely another condition in rail carbon, or the still higher grades. The figures that are given in Mr. Gathmann's paper I imagine are taken from the higher carbons, as it is very seldom that piping occurs in soft steel. J. W. RICHARDS, South Bethlehem,, Pa.-This contribution is very welcome, and I understand that the process of Mr. Gathmann is in practical use and has proven successful. I believe the experience of steel makers is that an ingot which has a pipe is of more solid structure, and therefore takes a great deal more work in the rolls and in mechanical treatment, than an ingot which has some blow-holes. The density of the piped steel is undoubtedly increased. My opinion is that it is un-

Jan 12, 1915

By D. G. Hartley, P. C. Hayward, K. R. Weller, U. J. Sterns

The major copper loss at Mount Lyell is in the coarsest particles presented to flotation. An analysis of data collected from the five Primary and six secondary ball mill circuits showed that grinding was limited by low breakage rates in secondary mills, possibly due to oversize balk. For five months, the make-up ball size for one secondary mill was reduced from 50 to 30 mm (2 to 1.1 in.). Frequent steady-state tests indicated that overall average breakage rates could be increased by about 70% using smaller balk. A mathematical simulation of the whole circuit with increased breakage rates showed that the resultant finer grind was likely to improve copper recoveries by about 2%.

Jan 1, 1984

By Henry G. Granger

A residence of 14 Sears in the Republic of Colombia, spent . in almost continuous traveling and prospecting-trips, has given me an intimate knowledge of the resources of that wonderful country. The man who best knows Colombia is unquestionably General Rafael Reyes, President of the Republic for the past three years, and with seven years more to serve in his present term. Such is the strength of his personality and the wisdom of his policies that his term of office will no doubt endure as long as he is milling to serve. The vastly improved economic situation and the brilliant outlook for Colombia are so directly due to the influence of President Reyes that a few lines concerning him will not be amiss, if they serve towards a better understanding of his personality. Born of a distinguished ancestry in the mountain~ of Boyaca, he is now 57 years old, just the age of his friend Porfirio Diaz when he began the work which has placed Mexico in the rank of great modern nations. It was Reyes who came to Washington to protest against the action of the government of the United States of America in

Jan 1, 1909

By H. L. Riley, B. W. Gandrud

As far as the present writers know, this system of flotation has not been used elsewhere in this country, but in the last couple of years it has been introduced, with minor variations, at one plant in England and one in Wales. The system has been described and discussed in a number of publications. The following is quoted from an abstract of the latest of these," a paper presented at an International Conference on Industrial Combustion in 1952. On the basis of experience to date with the commercial plants, it is believed that the kerosene-flotation process incorporates all the necessary elements to make it greatly superior to anything else now available for treating of fines in wet processes of coal preparation. Additional study and investigation are still needed, however, to determine if certain phases of the process can be improved to such an extent as to make it generally satisfactory and acceptable to the industry. Further improvements will be needed with respect to the capacities of the flotation cells and the reagent consumption.

Nov 1, 1955

By James Marsh

INTRODUCTION Economists have long expressed suspicion of the economic theory of natural resource exhaustion, even in writing articles which have contributed to it (1). Indeed, the gap which separates the pure theory from practical management seems unusually wide. It is doubtful whether a mine manager could possibly know enough about the relevant parameters of his mine to steer it along the optimal paths described by the theorists (2). Nevertheless, enough faith in the theory remains that mine managers are suspected of being a separate breed whose behavior must be studied in special courses using specialized text-books, collections of readings, and journals (3). The implied hypothesis, that mines and natural resource firms are managed differently than other firms, is the subject of this paper. In the next section the theory is developed and analyzed. In section III, I discuss the implications of the statistical results that have been obtained. Finally, conclusions are reserved for section IV. THE MODEL A key difference between the traditional theory of natural resource production and that of other forms lies in the set of variables which ire assumed to jointly determine the quantity of output the firm will produce. Output, in the non-resource case, is assumed to be a function of k clearly definable and distinguishable inputs or factors of production, viz., y = f(xl, x2, ..., xk), (1) here

Jan 1, 1977

By L. H. de Wald, J. Walter Scott

The removal of lead by fire refining methods from copper of electrolytic quality is growing in importance. Particularly is this true of the refining of secondary copper and copper cathodes obtained from electrolytic cells where lead is used as the anode material, as in the electrolysis of ore-leaching solutions and foul electrolyte. When investigating the removal of small amounts of lead from molten copper in a reverberatory furnace during the refining of secondary copper of otherwise electrolytic copper quality,' it was found necessary first to know something about the distribution of the lead throughout the bath. The authors believe that it is not generally known how small amounts of lead as an impurity are distributed in a molten copper bath; that is, whether the lead is concentrated at the bottom or at the top, or whether it occurs more or less uniformly throughout the bath. The data contained in this report may help, therefore, in the development of a satisfactory fire refining method for the removal of this obstinate element from a molten copper bath. The first step was the development of a method for taking samples from various locations in the bath, at the surface and at various depths. The sampling device used, shown in Fig. 1, consisted of a 10-gram fireclay assay crucible fitted into a ring on the end of a steel rod handle of suitable length. A fireclay scorifier, 2 in. dia., with a ½-in. hole bored in the

Jan 1, 1930

By K. Thirumalai, D. P. Schlick

Longwall Technology has a potential of resulting in safety and productivity improvements of U.S. underground coal mining similar to those experienced by the introduction of continuous miner systems. The study presents a comprehensive national evaluation of longwall technology to assess the potential of longwalls to improve health and safety and coal productivity. The study was conducted by the authors during the spring of 1980 as part of MSHA New Technology Coordination activities and with a view to examine the factors that may limit the acceptance of longwall technology in the U.S. coal mining operations. The study points out areas where adjustments need to be made in MSHA regulations and enforcement to help Longwalls. A two-entry longwall system appears to offer a practical method of improving underground coal productivity and safety. Applying regulations that are primarily designed for room and pillar methods to longwall mining, in some instances, reduces the effectiveness and productivity benefits feasible by new technology application. Controlling dust is the single predominant problem in the design and operation of longwalls in the United States. The results of this study points out a need for a coordinated program between government and industries on dust control technologies for examining acceptable technological options to control dust in longwalls without restraining the production capability of the system.

Jan 1, 1981

By N. F. Dyson, T. R. Scott, M. R. Thornber, W. E. Ewers, M. Bussell

Leach liquors derived from the processing of nickel ores are generally highly contaminated and contain appreciable free acid. Methods are described for obtaining a commercial grade of concentrate from such solutions using pyrrhotite as the seed material to abstract nick- el, cobalt, etc. from solution. At temperatures in excess of 160° C., recoveries of 99% can be obtained from contaminated solutions where the free acidity is as high as 0.5 M in sulphuric acid. At lower temperatures down to 80° C., high recoveries can also be obtained either by adding H2S to the system with appropriate adjustment of the free acidity or by using "activated" pyrrhotite or artificial FeS in the system without prior addition of H2S. The methods are applicable to liquors derived from either oxide or sulphide ores, and the products are suitable for smelting or other known processes used to obtain pure metals. The mechanism of the reaction appears to vary with the operating temperature, and the results ye therefore discussed in the light of electron probe and optical microscopic studies.

Jan 1, 1973