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By S. Chander, D. W. Fuerstenau

The inherently sluggish nature of the reactions involving sulfide minerals, particularly molybdenite, in aqueous solutions under ambient flotation conditions make their investigation complicated and difficult. Since the physicochemical nature of sulfides is known to be controlled by electrochemical reactions, a number of attempts have been made in the past to study sulfide mineral-collector interactions through rest potential and electrode polarization measurements. The purpose of the present investigation was to study the interaction of potassium diethyldithiophosphate (KDTP) with molybdenite. In the present investigation of the interaction of KDTP at the molydenite surface, molybdenite electrode rest potential measurements and electrode polarization behavior were experimentally determined under various solution conditions. The standard reduction potential for the equilibrium between dithiophosphate ions (DTP-) and bis(diethoxythiophosphoryl)disulfide (DTP) [(DTP). + 2e :i7-± 2DTP- (1)] can be evaluated from the electrode rest potential measurements on a platinum electrode in deoxygenated KDTP solutions saturated with freshly prepared (DTP)2. Experimental A platinum wire was used as the electrode for potential measurements. Prior to each measurement the elec-

Jan 1, 1975

By C. B. Foster, S. I. Freedman, E. M. Jamgochian

Coal-oil mixture (COM) combustion technology is regarded by the US Department of Energy (DOE) as near term and Potentially applicable to existing utility and industrial steam generators and for injection into blast furnaces. From work done previously, it has been established that COM can be burned in existing boilers and blast furnaces. Therefore, the issues being addressed by the current DOE program are: (1) determination of best available technology to achieve environmentally acceptable long-term reliable operation and (2) determination of applications for which COM can be utilized economically. Some of the technological options have begun to be determined by projects already under way. However, many projects are still in the early stages of development.

Jan 1, 1980

By Johnson Crawford, Alan H. Hoagland

Zinc mining at Jefferson City began in 1854 with small scale production of oxidized ore from open pits. Significant production began in 1913 with the development of the Mascot Mine by the American Zinc Company. In 1965, four flotation mills were treating crude ore at the rate of about 12,000 tons per day and the Mascot-Jefferson City district currently is the largest zinc producing area in the United States. The producing mines, Mascot, Young, North Friends Station, New Market Zinc, Grasselli, Davis-Bible, Coy, and the Jefferson City, are 15 to 28 miles northeast of Knoxville in the Valley and Ridge physiographic province, an area of gentle relief lying between the more rugged Great Smoky Mountains and the Cumberland escarpment. The ore is strata bound, occurring essentially within a stratigraphic range of 200 feet in the Lower Kingsport and Upper Longview formations of Lower Ordovician age. In the lower strata of the mineralized section, the ore generally is found in coarsely crystalline elastic dolomite breccia containing silica and chert debris within a sequence of aphanitic limestones. The upper strata of the mineralized section are fine-grained primary dolomites that, in the ore zones, have been fragmented in mosaic patterns by solution collapse with the interfragmental space filled by white gangue dolomite and sphalerite. The mineralogy is unusually simple, sphalerite being the only important sulfide. Pyrite is very sparse. Dolomite gangue is abundant, silica was deposited in quite small amounts, calcite is minor, and fluorite and barite are very rare. The principal ore controlling structures are rubble breccia zones that were formed during the post-Lower Ordovician-pre-Middle Ordovician erosion interval by supergene solution as a phase of the development of a regional karst system of underground drainage that extended to' depths of at least 800 feet. The major Appalachian orogenic structures are post-ore and have been superimposed on the ore bodies. There is substantial evidence to support the current thinking of the writers that the ore deposits were formed at a depth not exc1~eding 800 feet.

Jan 1, 1968

By R. W. Fountain, J. F. Libsch

ONSIDERABLE time and effort have been ex- pended recently in research designed to provide a better understanding of the solid state transformations leading to the permanent magnet qualities of many commercial alloys. The knowledge derived from these investigations has resulted in the development of new magnetic materials as well as improvements in some of the older materials. The permanent magnet qualities of the newer alloys having high residual inductions and high coercive force values, have been attributed to the precipitation of a second phase or an order-disorder transformation in a solid solution. The ternary Co-Fe-V alloys provide an interesting group of magnetic materials having a wide range of magnetic properties. The low vanadium alloys' possess soft magnetic properties similar to the binary Co-Fe alloys, while at higher vanadium contents (about 10 pct) interesting permanent magnet properties are obtained.2,3 Previous work by Nesbitt' on the ternary Co-Fe-V permanent magnet materials, resulted in the conclusion that the precipitation of a second phase, ?, was responsible for the permanent magnet qualities of these alloys. However, unlike the conventional precipitation hardening alloys, the ? phase, which is stable at high temperatures, is precipitated in the low temperature a phase upon aging. Recent work by Geisler and Martin"." has established that the order-disorder reaction inherent in the binary Co-Fe alloys is also present in the ternary Co-Fe-V alloys. On the basis of their investigation, it was proposed that ordering of the a phase is also a possible explanation of the mechanical and magnetic hardening in these alloys. Thus, it appears that the Co-Fe-V alloys are rather unique in that two solid state transformations are taking place which may account for the properties of these alloys. In view of these facts, the present investigation was undertaken to study the mechanism of mechanical and magnetic hardening in the 10 pct V-Co-Fe alloy with particular reference to the role of the ? phase; and to correlate the results of this study with other magnetic properties. In addition, the influence of increasing vanadium contents on the transformation of Co-Fe alloys was also undertaken to supplement the main objective of the investigation. Experimental Procedure The Co-Fe-V alloys used for study consisted of: 1—a commercial lot of Vicalloy I, a 10 pct V alloy, and 2—alloys prepared by powder metallurgy and containing 52 pct Co and 0 to 14 pct V, balance iron. The commercial alloy was received in the cast and forged condition and was used primarily for the detailed study of hardness, electrical resistivity, and magnetic properties of the 10 pct V alloy. The powder metallurgy alloys were prepared from electrolytic iron, commercial cobalt, and ferro-vanadium powders. The processing cycle was as follows: 1—Elemental powders were weighed and mechanically mixed for 24 hr. 2—Mixed powders were pressed at 60,000 psi into the form of bars 5/8 x 5/8 x 5 in. 3—Bars were sintered in an atmosphere of purified dry hydrogen for 24 hr at temperatures ranging from 1380" to 1340°C, depending upon the vanadium content. The as-sintered bars were cut in half; and one half was machined to 7/16 in. diam for thermal analysis. The remainder of the bar was hot forged to approximately 0.050 in. for X-ray diffraction analysis. Additional details of sample preparation are presented subsequently according to the type of test performed. Thermal Analysis Measurements One of the simplest and most widely used tools for determining phase relations as they change with temperature and composition is to study the rate of change of temperature of a material as heat is supplied or extracted at a constant rate. The thermal analysis method used in this investigation is the inverse-rate method described by Smith.'

Jan 1, 1954

By T. W. Beck

Roof bolter occupations in underground coal mines continue to experience overexposure to respirable dust. One potential source of dust in roof bolting operations is the exhaust from the roof bolter dust collection system. A wet exhaust conditioner (water box) has been developed to reduce dust emissions from the exhaust of the vacuum dust collection system on roof bolting machines. The exhaust conditioner consists of a muffler chamber and a water chamber with four internal partitions to direct airflow over the surface of the water. The National Institute for Occupational Safety and Health conducted a series of laboratory tests to assess the respirable dust capture ability of this device as compared to the standard exhaust muffler. To determine the dust collection efficiency, both devices were placed in the exhaust stream of a simulated roof bolter dust collection system. Gravimetric samplers were operated upstream and downstream of the exhaust conditioner and muffler to evaluate the ability to capture both respirable coal and limestone dust. Researchers observed a 41 % reduction in dust concentrations for the water exhaust conditioner in the laboratory configuration. Significant levels of dust deposition in the sampling chambers may have contributed to this effective capture rate.

Jan 1, 2012

By F. B. Plummer

PROGRESS during 1940 in oil-production technology has been confined largely to a steady advancement in practices inaugurated in previous years, rather than the introduction of any new startling process or technique. The usual changes, improvements and additions in production equipment have been introduced. An increased attention to, and interest in, research has been noteworthy, resulting in improved efficiency in operation of oil wells. control, utilization of reservoir energies and reduction of production costs.

Jan 1, 1941

By A. M. Beebee

IN the present century the coal and manufactured gas industries have been eclipsed in public interest by oil, natural gas, and hydro- electric energy, which have had the benefit of rapid development and novelty. I sometimes wish that our social- order were such that hydro power had been developed first, that the use of gas from coal had never been seriously considered, and that our domestic energy requirements were supplied by other fuels. Sup- pose the manufacture of gas from coal should then come on the scene at the present time with the current plight of the railroads, coal regions, and labor generally, presenting the fact that it could increase the amount of coal mined and shipped by the railroads by some 16,000,000 tons, and increase the coal used at existing u plants five times. Imagine the great public interest that would be manifested; it would supply the cooking and water-heating requirements of a community with a superior character of service at a cost to the customer approximately half that which had obtained previously. Would not such a situation be heralded as the salvation of our country and all help be given it?

Jan 1, 1940

By P. S. Rudman

Laves phases, AB2, are considered as Izerrzisub-stitutional solutions m1hich are defined by a one-for-truo replacement scheme. Atomic-size tnisfit is considered in terms of deviations of the ratio 2V°b/V°A from unity, where v° = atomic volume. A simple elastic model has been used to calculated deviations from "Vegard&apos;s law of atomic vol-umes". Comparison has been made between calculated and observed atomic-volume deviations fov 222 Laves phases. Agreement is generally very good although there ave some few exceptions which appear to be excusable in terms of electronic changes that ore beyond the scope of the present model. We can consider the formation of a binary sub-stitutional solution A-B from an A solvent as one-for-one replacements of A atoms by B atoms. As the atomic-size ratio deviates from unity, the solution becomes thermodynamically less stable and hence more restricted because of atomic-misfit strain energy. In accordance with our previously presented conclusion1 that the atomic volume, v, is in general the most appropriate measure of atomic size, the ideal size ratio for a binary sub-stitutional solution is vg/vA = 1. The Laves phases have been described by Berry and Raynor2 in terms of various stacking sequences of hexagonal layers of B atoms for the three structures MgZn2(C14), MgCu2(C15), and MgNi2(C36). To form the Laves phase of ideal composition AB, we start with complete hexagonal layers of B atoms in the appropriate stacking sequence and we remove, according to an appropriate scheme for each structure, two out of every four B atoms and replace the two removed atoms by one A atom. We thus might expect to find that the ideal size ratio for the Laves phases is 2v/B/ VA= 1. From this point of view, then, we call Laves phases hemi-substitutional solutions since we employ one-for-two replacements. By analogy with substitutional solutions we can expect for Laves phases that as the ratio 2VB/Va deviates from unity the phase occurrence will be more restricted. Laves3 has plotted the distribution of Laves phases as a function of the radius ratio, ?A/rB, and found that, while the distribution extended from 1.05 < rA/B < 1.50, the

Jan 1, 1965

By D. S. Sanders

IN the four mills of the Cerro de Pasco Copper Corp. in Peru, some 3000 tons of complex sulphide ores are treated daily, with four kinds of concentrates produced: copper, lead, zinc, and pyrite, each containing values in silver, gold, bismuth, and some other metals. Copper occurs in the various ores as chalcopyrite, enargite, tetrahedrite, tenantite, bournonite, and chalcocite; lead as galena; and zinc as sphalerite and marmatite. Small amounts of silver and tungsten minerals are also present. The gangue consist mainly of shale, quartzite, calcite, rhodochrosite, pyrite, and pyrrhotite. In general the values are freed with a relatively coarse grind, about 70 prr cent minus 200 mesh being the finest to which the pulps are ground. In Morococha and Casapalca however. sphalerite particles much finer than this contain inclusions of chalcopyrit r. At Cerro de Pasco the silver and gold are present in all sizes of the ground pyrite.

Jan 1, 1945

By Willard P. Ward

SOME TIME in the year 1874 or 1875, I conceived the idea that spiegeleisen might be made -in a blast furnace from ores that were not carbonates, and which did not contain both manganese and iron in the same ore. Up to this time, such ores had formed the basis of all the spiegel that had been produced; and all the ferromanganese that was on the market before 1875 was made in crucibles, and cost about 00 per ton, for 80 per cent. Mn. I consulted the great steel metallurgist of the day, Alexander Holley, who listened attentively to what I had to say, and told me he did not think my plan was practical, so I abandoned it for the time being. But I was so stubborn that I could not get the notion out of my head. It seemed to me that a good metallurgist should be able to work the thing out in some way. I had already had some experience in smelting refractory lead ores in Utah, and was young and not lacking in self confidence, so after waiting a bit, I got Anton Eilers, the best all-around metallurgist I knew, and J. H. Bramwell, the best iron blast-furnace man I knew, both intimate friends of -mine, to come to my place in Bartow County, Georgia, and look over things. They remained for several days, and made all the examination they thought necessary; and they also advised me to give up the project, and either to keep the furnace running on car-wheel iron or to blow it out. After my talk with Holley, I improved my plant in several ways. I closed the top of the furnace, put in a hot-blast stove, a steam boiler and a Weimer blowing-engine which gave me blast enough, at a pressure high enough for all the requirements of, the furnace, and which I could bring up to a temperature of 600° to 700° F.

Jan 1, 1921

By AIME AIME

N EARLY 1300 members and guests crowded the halls of the Engineering Societies Building during the winter meeting of the Institute just closed, and more than 600 attended the banquet. In variety of program, quality of papers, interest in discussion, and brilliance of social features, the meeting maintained the high reputation of the past. Nothing elaborate in the way of excursions was attempted, experience having proved that February weather in New York is much too uncertain to warrant extensive field trips. A sight-seeing journey up the Hudson to the Bear Mountain bridge was, however, made despite the snows of the week before and the week after. The annual business meeting, while attended by a minority of the members in the building, was marked by the display of keen interest in the work and called out several interesting discussions. The excellent reports of the committees that had organized their work and directed it along definite lines, emphasized the need of funds with which to support assistants or Fellows who shall correlate and put to the highest use the facilities of the Institute in research along technical lines. This thought was developed at the banquet by the retiring president, J. V. W. Reynders, and it is expected that the Directors will take early steps to collect a fund for this purpose. The number of the individual sessions was too great and the papers and discussions too numerous to permit mention here of all the features of inter- est. A general review only follows. The papers and detailed discussions will be printed and sent to members as promptly as possible.

Jan 1, 1926

By AIME AIME

HIS many admirers regard the "official"&apos; candidate for president of the Institute in 1934 as far above the average in ability and capacity; but perhaps his outstanding characteristic is dependability. Some men of great brilliance succeed indifferently because they cannot be relied upon. When Howard Nichols Eavenson undertakes to do something he either does it, or he proves to his own satisfaction that the particular object is not attainable. And the latter outcome is exceptional because his judgment is so good that he generally foresees the impossibility and selects in advance a practical alternative. Though a tireless worker he is pretty sure that his energy is not spent futilely.

Jan 1, 1933

By LUIS EAIYLNN SALAS

IF the ordinary wet method be attempted for silver-bullion containing tin, much trouble is experienced, varying with the amount of tin present. Even with a percentage as low as 0.05, the end-point is masked by a persistent turbidity, while with amounts ranging from 0.5 per cent. upward, the determination of the exact end-point is impossible, owing to the finely divided or colloidal metastannic acid resisting all efforts to cause it to settle, or to give a clear supernatant liquid. The object of the following experiments was to seek a remedy for these difficulties, and to find the conditions whereby the Gay Lussac method might be applied directly to these bullions. Material containing tin is met with frequently in bullion from Mexico or Bolivia; and tin is carried (sometimes in large quantities) in jewelers&apos; sweeps. 1. A bullion was prepared containing Ag, 74; Cu, 25; and Sn, 1 per cent. A weighed amount was treated by the humid assay-method as if it were an ordinary bullion free from tin. Ten cc. of HNO3 (1.21) was added, and the bottle was heated until all traces of red fumes had been expelled. Before heating, the solutions were moderately turbid; and after heating, the turbidity greatly increased. One hundred cc. of normal NaCl solution was added and the bottle was shaken vigorously at intervals during 30 min. The turbidity persisted. The bottle was allowed to stand over

Mar 1, 1912

By E. P. Bayer

MESABI RANGE ore is mined largely by the open-pit method. This involves having available at all times sufficient working places which in combination will produce ore of guaranteed analysis. Fast- loading power shovels turn out under favorable conditions 1000 tons per hour from each unit. Each unit loads ore differing materially in analysis from that loaded by the others, One may load high grade, another low grade, and another may be in a mixed bank with the lead ore so placed that the product must be mixed at the shovel before it is loaded into cars. In such cases the bank is combed with the bucket, the door being left open to permit the material to fall through.

Jan 1, 1937

By M. C. LAKE

THE industrial development of the United States has been stimulated by the presence of high-grade iron ore in the Lake Superior district. These great deposits have been susceptible to economical extraction and are conveniently located for cheap lake vessel transportation to the great consuming centers. The district furnishes from 80 to 85 per cent of the iron ore annually consumed in the United States, and a full understanding of the available supply of this great commodity is so important that it is well to consider whether or not the industrial supremacy and national independence attained as a result of the abundance of cheap ore are permanent. The enormous deposits of high-grade ore available in the Lake Superior district have been the foundation upon which the vast industrial structure of the steel and allied industries has been built. It is extremely important to the country as a whole, and especially to those States and communities now dependent on Lake Superior ore for their prosperity, that their industries shall retain the particular advantages with which they are now endowed, and that a generous supply of high-grade raw material be available for their consumption at a satisfactory cost. The steel industry is so basic and fundamental that any fluctuation in the cost of its finished products as determined by the supply and cost of the raw materials involved in its manufacture will necessarily affect the business of a wide variety of industries which are dependent on it.

Jan 1, 1926

By F. C. Canney

Geochemical prospecting seeks hidden mineral deposits by sampling for variations in the chemical composition of naturally occurring materials. Usually the samples are of soils and other products of weathering and erosion—surface materials extremely susceptible to contamination by human activities. Except when a survey is conducted well away from populated areas, contamination is an ever-present hazard. The program&apos;s success is particularly endangered when the contaminants are the elements sought; if these occur erratically throughout an area, spurious anomalies completely unrelated to mineralized areas can be formed. Evenly distributed contamination can be dangerous too, if it raises the background to such a level that true anomalies can no longer be easily detected. Suppose, for example, that in an area where the lead background is 20 parts per million the soil over a lead vein contains 1000 ppm of lead. Here the contrast would be 50 to 1, which is very satisfactory for geochemical surveying. Now if 1000 ppm of lead from some source were added evenly to the soil in this area, the contrast would be reduced to about 2 to 1, and the anomaly would no longer be readily detectable because a threshold of significance twice the value of the background is the minimum generally used for interpreting geochemical data. Of the many possible sources of contamination, probably most important are smelter fumes, which may distribute large quantities of metal contaminants over many square miles of ground. For several reasons, the investigation reported here was begun in the Coeur d&apos;Alene district in northern Idaho: 1) a lead smelter has been operated in this district since 1917 and an electrolytic zinc plant since 1928, and presumably the contamination patterns are strongly developed; 2) to evaluate the usefulness of certain geochemical techniques, V. C. Kennedy and S. W. Hobbs of the USGS had already studied the distribution of copper, lead, and zinc in the soils (both in background areas and other veins) and in the water and plants, providing a criterion for measuring the magnitude and effect of soil contamination; 3) one of the economically important parts of the district lies south of the South Fork of Coeur d&apos;Alene River and within a radius of five miles of the reduction plants near Smelterville (Fig. 1). In this area, and in the entire district, conventional methods of prospecting are hindered by heavy vegetation and thick soil cover, and the possibility of contamination by smelter fumes has discouraged geochemical prospecting. Should data reveal that geochemical prospecting could be done successfully in such an area, a particularly useful tool would be available to mining companies and prospectors searching for concealed orebodies in this economically important part of the district. The field work on which this report is based was done from July 28 to 31, 1955. It should be emphasized that this was reconnaissance study only, and therefore far from exhaustive. Previous Investigations in U. S. : The first geochemical survey known to have been affected by contamination was conducted in 1940—a geobotan-ical reconnaissance made in the Michigan copper district by a private company. Geologists found striking variations in the copper content of oak and maple leaves, but unfortunately the high copper isograds of the study seemed to be related more to the Calumet and Hecla copper smelter fall-out than to mineralized ground.&apos; The leaves of one oak tree near the smelter contained 0.4 pct Cu. Similar contamination was reported by Clarke (Ref. 2, p. 41), who conducted experimental geochemical soil and botanical surveys at Ray, Ariz. He found that the leaves of oak trees growing in unmineralized ground near Superior, Ariz., contained more copper than the leaves of oak trees growing on the capping of the Ray orebody and attributed this fact to contamination from the fumes of the Magma smelter at Superior. According to H. E. Hawkes,3 soils and stream sediments in the Superior area are also severely contaminated. Hawkes&apos; work there has shown a copper content averaging 0.5 pct in the surface horizons of soils within one mile of the smelter stack. Samples taken only a few inches below the anomalous surface samples showed only background copper values. In 1950 L. C. Huff&apos; of the USGS made a geochemical survey in an area near Jerome, Ariz., and found considerable zinc and copper in the soils over unmineralized basalt close to Clarkedale, Ariz., and over limestone close to Jerome. As the amounts were notably greater than could reasonably be expected to be derived from the underlying rocks, Huff suspected airborne contamination from the smelter at Clarkedale. Description of Area: The area sampled in detail (Fig. 1) for the study presented here is one of strong relief. The dominant watercourse is the westward-flowing South Fork of the Coeur d&apos;Alene River. East of Kellogg the South Fork flows in a rather narrow canyon, but its valley floor widens considerably to the west where much of the flood plain is covered by an extensive veneer of mining, milling, and smelting debris. South of the South Fork and between Big Creek and Pine Creek is a mountainous area where

Jan 1, 1960

By E. J. Duggan

CLIMAX ore is an altered and highly silicified granite, about half of the gangue being quartz. Molybdenite is the only mineral recovered and most of it is intimately associated with the quartz in fine veinlets. Other minerals are molybdite, pyrite, and chalcopyrite. Although the molybdite may be readily extracted by hydrometallurgical methods, its content is too low to make this profitable. The pyrite ranges from 2 to 5 per cent and the chalcopyrite from 0.03 to 0.05 per cent. There is not enough copper to make its recovery attractive and one of the problems is its elimination, and that of pyrite iron, from the final product. On account of the high degree of dissemination of the molybdenite and the necessity of eliminating the iron and copper, fine-grinding followed by flotation is the only known feasible method of concentration. Two factors, peculiar to Climax ore, have a predominating influence on the metallurgical attack: (1) Molybdenite is one of the most easily floated minerals. High recoveries may be made with pine oil alone if the

Jan 1, 1946

By ALFRED T. BARR

In certain areas of the New Cornelia pit, considerable secondary blasting is necessary to reduce oversized boulders, formed from primary blasting, to pieces which will pass the 41/2-cu yd dippers on the shovels. Some of the boulders are &apos;dobied, but when time permits they are blockholed and blasted. In most instances one hole drilled to a depth of 2 to 3 ft and blasted with 1/3 to 1/2 of a stick of powder will break a boulder satisfactorily. Blockholing is normally done by using a jackhammer of the 55-lb class, 1-in. round drill steel, and detachable steel bits, 2-in. gauge when new. A bit change is usually made after the completion of each hole. The use of light drilling equipment in blockholing is desirable, both from the standpoint of safety and ease of doing the work, and when it was seen there was a possibility of using a lighter jackhammer through the use of tungsten-carbide bits and at the same time get at least the same drilling efficiency as with the standard equipment, it was decided to test tungsten-carbide bits. The claims for long life of the bits and footage drilled before resharpening gave hopes of eliminating much of the delay time in changing bits which is unavoidable with the use of steel bits. and thus gain in actual drilling time.

Jan 1, 1949

Jan 1, 1880

By Rollin A. Pallanch

THE Midvale mill of the United States Smelting Refining and Mining Company is situated on a flat site whose elevation is 50 ft above that of the Jordan River. Tailings are impounded in the area between the river and the flat upon which the mill and railroad switchyard are located. The water supply is pumped from the Galena canal which leads from the river at a point some ten miles to the south. The mill has a present capacity of approximately 1700 tons daily. It started out originally in 1926 as a 750 ton three-unit plant. The tonnage was gradually increased to 1200 tons by 1934, and in late 1935 a fourth unit was added. The accompanying flowsheet shows the principal equipment and how it is utilized. The ore is principally sulphide with varying degrees of oxidation, with individual lots ranging widely in both precious and base metal content. In each of the four individual units of the mill there will often be mixtures of as

Jan 1, 1948