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By Otto Rellensmann, Eugene P. Pfleider

For many years mine surveyors and exploration engineers have sought an accurate means of transferring meridian underground by using the gyro-compass. These efforts have generally failed, either because they were inaccurate or because the size and cost of the unit were prohibitive. During the past ten years, however, great strides have been made. Autonetics in California has developed a comparatively light-weight (100-lb) gyro-theodolite, and the Institute for Mine Surveying at Clausthal Mining Academy in Germany has developed an instrument that is accurate to within 20" to 30" of arc. Concurrently, Minneapolis-Honeywell has produced an astounding gyro, the size of a salt shaker, that weighs less than 0.5 lb and compares favorably in performance with the 50-lb gyros of conventional design. This unit, designed for missile guidance, should be adaptable for surveying small boreholes. Given the proper interest and approach from the engineering fraternity, excellent gyro- compasses could probably be available for accurate underground survey work at nominal cost within the next three years. Principles of the Gyro-Compass: The gyro- compass, used for 50 years as a navigational instrument in ships and aircraft, senses the turning axis of the earth and points out true polar north. It does this by employing the earth's rotation, the force of gravity, and the precession characteristics of a gyro. For further details the reader is referred to several excellent publications1-3 covering the principles and application of the gyroscope.

Jan 5, 1959

By Bryon W. Cheever

The greatest objection to be brought against the present methods for estimating phosphorus in iron and steel, is the time consumed in the operation. The following method, originated and perfected by Mr. E. D. Campbell, assistant in the chemical laboratory of the University of Michigan, will, 1 think, if carefully followed out, give results that are sufficiently accurate for technical purposes, and will give them in less time than they can be obtained by any other process. The process consists in comparing the color obtained by the action of stannous chloride upon a solution of the phospho-molybdate precipitate obtained from the solution of iron or steel, with that obtained from a standard solution of molybdie acid which represents a given amount of phosphorus. The operation is as follows : Take of ordinary steel 1 grm. and treat as in any of the wellknown processes until the phosphorus is precipitated as ammoniumphospho-molybdate. When precipitated, the phospho-molybdate precipitate is filtered out, thoroughly washed with an acid solution of ammonium nitrate, and, finally, twice with water, to remove most of the ammonium nitrate. The precipitate is then dissolved in about 1 c. c. of 10 per cent. potassium hydrate, which is let fall drop by drop on the filter till the precipitate is dissolved ; the filter is now washed with about 25 or 30 c. c. of water, and the potassium hydrate solution, which now consists of 25-32 c. c. of solution, is boiled until the peculiar frothy appearance, which first appears on boiling, is entirely gone. The solution is then cooled until perfectly cold, and about 10 or 15 c. c. of strong hydrochloric acid added ; if the solution is kept cold this will form no precipitate, but a light yellow or colorless solution. The solution is now ready for the addition of stannous chloride, and the subsequent comparison of color produced with that obtained from the standard molybdie acid. The comparison is made in tubes that are calibrated like carbon-tubes, but which are larger, about 5/8-inch bore, and graduated to 100 c. c.; this makes them about 18 inches long. To make the comparison of color, first transfer the now acid solu

Jan 1, 1886

Cooperation will be the keynote of the meeting of the Institute that will be held in New York on February 17 to 20. Arrangements are being made for two joint sessions with the Canadian Mining Institute, on the same day, which therefore will be known as Canadian Mining Institute Day. On the afternoon of Wednesday, February 19, there will be a joint session with the American Institute of Electrical Engineers. Besides, we will receive six or eight papers through the National Research Council, four of which will be presented at the National Research Council Session. In March, at the next meeting, of the Canadian Mining Institute, there will be an American Institute of Mining Engineers Day. The plan is to have the same subjects discussed at both meetings, but by different speakers. One speaker on each subject will represent the Canadian Mining Institute, and one speaker the American Institute of Mining Engineers. The Canadians and the Americans who will speak in Canada are expected to attend the discussion in New York. In addition the discussion at the New York meeting will be sent to Canada in printed form, so that the Canadian discussion will be a continuation of the former. At the joint session with the American Institute of Electrical Engineers, there will -be presented six very important papers on the subject of Electric Welding, one by the Chairman of the Electric Welding Research Committee of the National Research Council, another by the Chairman of the Metallurgical Sub-committee of that same Committee, and a third by Comfort A. Adams, President of the American Institute of Electrical Engineers and Chairman of the Welding Committee of the Emergency Fleet Corporation. We will receive six or eight papers through the National Research Council. These papers are results of recent investigations and represent the last word in their respective subjects. The excursion on Thursday, February 20, will be to Newark Bay to visit the Federal Shipyard where the first, electric-welded ship is being built. Philip W. Henry is chairman of the excursion committee of arrangements.

Jan 1, 1919

By M. B. Bever, A. K. Jena

In the investigation reported here, calorimetric measurements have been made to determine the heat of formation of the compound AuSb2 and the partial gram-atomic enthalpies of antimony and gold in dilute solution in liquid tin and their enthalpy interaction coefficients. In order to interpret the behavior of antimony and gold in dilute solution in tin, nonzero values are assigned to the energies of bonds between like solute atoms relative to the pure solute state. Sa.mples of the compound AuSb2 were prepared by melting stoichiometric amounts of antimony and gold (99.999 pct pure) in evacuated and sealed Vycor tubes, which were shaken vigorously and quenched in water. The ingots were annealed in evacuated and sealed tubes at approximately 700°K for 2 weeks. Metallo-graphic and X-ray examinations gave no indication of second phases or microsegregation. The samples were added from 273°K to tin-rich solutions in a solution calorimeter1 maintained at 623°K. The calorimeter was calibrated with tin; the heat content of tin, H623°K- H273°K, was taken as 4.08 kcal per g-atom.2 In each calorimetric run at least four additions were made. The total concentration of solutes in the bath at the end of any run did not exceed 1 at. pct. The measured heat effect of an addition was plotted against the average of the atom fractions x of Sb + Au in solution before and after that addition. From this plot the heat effect at infinite dilution h,,, and the composition dependence of the heat effect dh/dx in the composition range 0 < x < 0.01 were obtained. The results for the additions of antimony, mixtures of antimony and gold, and the compound AuSb2 are listed in Table I. The heat effect h on addition of a sample of the compound AuSb2 or a mechanical mixture of antimony and gold at 273°K to a tin-rich solution at 623°K can be expressed as:

Jan 1, 1969

By Rush Sill

THE processes of superficial alteration depend on physical conditions, environment, geologic history and chemical and mineralogical composition. Superficial alteration is confined particularly to the zone of shallow circulation, as this is the zone of solution; its rocks are open and the circulation within it is compara-tively rapid. The enrichment of ore deposits in this zone, therefore, is of special interest. The depth of the vadose, or zone of shallow circula-tion, is variable, because its lower limit depends on the variable level of ground water. In moist, hilly countries its depth varies from a few feet to several hundred feet. In arid regions where the rainfall is low and evaporation great, this zone may extend to much greater depths. Permeability of the deposits . is essential to the downward migration of metals. In rocks, that have been fractured since the primary ore was deposited, there is generally more extensive and deeper enrichment than in ore deposits that have been but slightly fractured. A warm climate increases chemical action and abundant rain fall is favorable to enrichment. Low relief and slow erosion give long periods of weathering and thorough leaching.

Jan 9, 1922

There was such a large demand for copies of the speech of Herbert Hoover at the A. I. M. E. dinner given in his honor on Sept. 16, that a special edition has been run off; anyone desiring copies may obtain them by applying at the office of the Secretary.

Jan 12, 1919

By Ralph H. Sweetser

OF SPECIAL importance in the design and construction of an iron blast-furnace plant are tile raw materials to be employed. Obviously the iron must come from some ore of that metal, but the many kinds available lead to important differences in plant arrangement, and in the design of furnaces and accessory equipment. For instance, the bulk of the gangue in the ore is subject to wide variation as is that of the ash in the fuel. A gradual increase in the bulk of raw material necessary to produce a ton of pig iron has been noted, but this has been more than offset, so far as costs of operation are concerned, by improvements in the machinery used for handling large quantities of ore. coal limestone, and slag. The mechanization of coal and iron-ore mining. the building of big ore boats and limestone carriers, of ore docks for fast loading and unloading, and the general use of heavy railroad equipment have all contributed to greatly reducing the number of man- hours required to mine, transport, and manufacture the raw materials into a ton of pig iron. This looks like a big saving and it is. If it were not for these big labor saving machines it would be impossible to produce the tonnage of iron and steel that is made each year in this country. On the other hand, the total capital investment necessary to bring down the man-hours per ton of pig iron to a 2.3 hours average at the blast furnace and to a total of only 12 man-hours from ore to metal (see Table 1) is so great that even the present high price of pig iron is probably not far above the true cost of manufacture when all the fixed charges are properly included.

Jan 1, 1939

By Garfield Schnee

MACHINERY has not taken the place of manual labor in steep pitch coal in the anthracite field and there is a shortage of miners experienced in this type of work. To overcome these difficulties several coal companies have resorted to different types of mining such as the diamond or zig-zag method, the slant method, long hole drilling, and several other variations. For the past 5 years the diamond shape method has been used extensively in the heavy pitching beds of both the Knickerbocker and Yatesville basins at Knickerbocker colliery of the Philadelphia & Reading Coal & Iron Co.

Jan 10, 1950

Advantages to Members of Our Advertising Section.-It is our intention to make the advertising section of the Bulletin as comprehensive as possible, so that members can turn to it for complete information as to where to buy the best mining and metallurgical supplies at the lowest prices. No firms or supplies of dubious reputation are advertised in the Bulletin.. If members, in buying any material, will refer to the advertisement of that material in the Bulletin, or if they do not find it advertised in the Bulletin, will, when ordering, ask the manufacturers why the goods were not advertised in the Institute publication, it will be of material benefit to all of us, because the chief reason why advertisers .are unable to trace direct results is because purchasers do not mention the Bulletin when writing. Finally, if members, when in need of anything whatsoever, will write to the Institute headquarters, an effort will be made to send them a complete list of manufacturers able to supply the desired materials of good quality. The furnishing of these lists will be a benefit to our Advertising Department, as well as to the members. We need .scarcely call attention to the advantages obtained by the members from the motley which advertising brings in, because all this money is returned directly to the members in one form or another.

Jan 7, 1913

By T. J. Whalen and Michael

The grain shape of the carbide in nickel-bowled ad cobalt-bonded titanium carbides was studied by microgiaphic examination, and the influcence of sintering atmosphere, sintering substl-after, ami the amount of metal binder on the grain shape was determined. If was found that the Carbide grain cross sections in the nickel and cobalt cermets ranged from round to angular, depending on the sintering conditions. The spheroidization of the carbides in both cobalt-bonded and nickel-bonded titanium carbides may be attribicted to oxygen. In the course of studies on titanium-carbide base cermets, various investigators have reported on the shape of the carbide grains, and it was noticed that grain shapes were obtained which were either spheroids, or polygons with rounded or square edges. It was also noted that the shapes of the carbide grains changed with time or composition. skolnickl showed that the titanium-carbide grains. after infiltration in vacuum with nickel tended to spheroi- dize with time. The titanium-carbide skeleton was located on a beryllia plate during infiltration. Gur-land,&apos; who studied the microstructure of titanium carbide-cobalt compacts, showed that the carbide grains are round after 1 hr at 1450oC in a hydrogen atmosphere and angular after 7 hr at the same temperature. Goetzel3 has found that the carbide grains in compacts with a high binder content. 40 to 60 pet. tend to be spheroidized. whereas Blumenthal and silverman4 pointed out that the higher binder contents could yield either round or rectangular grains with rounded edges. depending on the nature of the binder. It is the purpose of this paper to present experi-

Jan 1, 1961

By Wayne T. Brooks

The Occupational Safety and Health Act of 1970, although providing no precise definitions of safe and healthful working conditions, specifies mandatory duties, and methods and procedures -- "to assure so far as possible every working man and woman in the nation safe and healthful working conditions." The dynamics of the workplace ad the dynamics of this coextensive Act both spring from the same source. Both require at any given time an application of the then con- temporaneous highest state of the art. Both are flexible, ongoing, adaptive, changing; both advance by a blending of experience and research.

Jan 1, 1972

ABOUT 2 lb. of alumina (aluminum oxide) of high purity is required to produce a pound of metallic aluminum. Projected production of metallic aluminum in the United States is now seven to ten times the peacetime rate a few years ago. In the past, all the alumina for aluminum production in the United States has been obtained from bauxite. Part of the bauxite was mined in the United States--chiefly in Arkansas-and part was imported from Surinam. All of it was chemically treated in the United States to separate the greater part of the aluminum oxide from the bauxite, alkaline solutions being used, in a method known as the Bayer process. The ingredients of the bauxite other than alumina, such as the compounds of iron titanium, and silicon, constitute the tailings from the Bayer-process operation. This product contains sufficient iron to give it a red color and hence it is called "red mud." Lime and soda used in the processing, are also present. Varying amounts of alumina remain in the red mud, depending upon the characteristics of the bauxite, the effectiveness of the treatment, and in particular upon the amount of silica originally present in the bauxite. High-silica bauxites result in high alumina loss in the red mud.

Jan 1, 1942

By Andrew Button

INTRODUCTION This review deals with the controls exerted by unconformities on the stratigraphic and areal distribution of gold (and uranium) in Precambrian conglomerates. The relations described are drawn mainly from Precambrian basins in southern Africa, particularly the Witwatersrand Basin. The mining industry of South Africa started in earnest with the discovery of diamonds in 1866. Gold was first discovered in 1870, and in March of 1886, two out-of-luck prospectors stumbled across what was to become the world&apos;s greatest goldfield, in the vicinity of Johannesburg. George Harrison and George Walker sold their claims for a pittance and were heard of no more. The Witwatersrand goldfield has been in continuous operation since that time, some 150 mines having operated at one time or another. Deep mining technology developed here has allowed operations to proceed to depths approaching 13,000 feet. The Witwatersrand has produced some 55% of all the gold ever mined, and currently produces 60% of the world&apos;s supply, some 650,000 kg Au per year. To 1971, the Witwatersrand had produced some $32 billion of gold and $2 billion of uranium (when average prices were less than $35/oz. for Au and $10/lb. for U308). At present prices, the annual Witwatersrand production of close to 700,000 kg would be worth about $10 billion. Uranium was discovered in the Witwatersrand in 1923. In the $15-30/lb. bracket, the basin contains a reasonably assured plus

Jan 1, 1983

C. W. Kempton, Oro Blanco, Ariz.: In his interesting paper, Mr. Ingalls refers to reports of tin-deposits near Sain Alto, Zacatecas, Mexico. During 1891 I made some personal examinations of these deposits. They are, for the most part, located from 10 to 30 miles west of the town, in the Sierra del Fraile.

Jan 1, 1896

R. B. Sosman, * Kearny, N. J.—Mr. Sweetser brought out that in certain blastfurnace slag compositions a change of one or two tenths of a per cent may be quite significant. That is true not only of blast-furnace slags but of other compositions as well. We have all been up against the necessity of having to plot out equilibrium diagrams of this kind on a big enough scale so that we could actually use them, the

Jan 1, 1935

R. B. Sosman, * Kearny, N. J.—Mr. Sweetser brought out that in certain blastfurnace slag compositions a change of one or two tenths of a per cent may be quite significant. That is true not only of blast-furnace slags but of other compositions as well. We have all been up against the necessity of having to plot out equilibrium diagrams of this kind on a big enough scale so that we could actually use them, the

Jan 1, 1935

POSITIONS VACANT (Under this heading will be published notes sent to the Secretary of the Institute by members or other persons.) Metallurgist wanted for research in iron and steel. Man with experience in mills preferred. Salary $4,000. No. 13. Opening for a few technical graduates to act as instructors in mining to men at the mines under the supervision of the State mine inspector. Salary $1,800 per year. No. 14. ENGINEERS AVAILABLE (Under this heading will be published notes sent to the Secretary of the Institute by members or other persons.) Mining engineer and metallurgist open for engagement, as superintendent of mines or constructing engineer. Technically educated, with 14 years&apos; experience in United States and Latin America in concentration, amalgamation, cyaniding, constructing. Just finished building large modern all-sliming cyanide mill in Central America. No. 18.

Jan 4, 1914

By R. W. M. Lai

This paper presents a simple flotation kinetics model (Lai, 1981) along with a method of presenting the model in an informative graphical form. Examples are given for evaluating various flotation conditions and different ore types.

Jan 1, 1983

By L. C. Armstrong

Twice in the past two years and in two widely separated localities-one near Williamsville, Mo., and the other in the Allard Lake district of Quebec- the Contract Drilling Division of the Longyear Company has experienced perplexing difficulties in drilling granitoid igneous rocks. The rocks in both places are characterized by appreciable amounts of feldspar intimately intergrown with quartz particles of microscopic dimensions. The disappointingly slow rate of advance and the exceptionally high bortz loss, obtaining during the life of these two projects, are ascribed largely to the resistance to abrasion of these two minerals when arranged in this intergrown pattern. Whether all intergrowth-bearing igneous rocks would offer extraordinary resistance to bit progress cannot be stated with assurance on the strength of these experiences alone. More data on diamond drilling this sort of material in a number of localities are needed before any generalizations can be made safely.

Jan 1, 1949

By David Segura

THE Huitzuco mercury deposits have been described by C. W. Vaupell,1 therefore the general information such as location, history, production, etc. will not be repeated here. The present owners acquired the property when the deep levels of the Cruz mine were flooded, and it was believed that a relatively large tonnage of low-grade ore and fills would be encountered in the flooded section, because f the early mining methods used in the Cruz mine. The mine was partly unwatered and about 187,000 tons of fills was pit-sampled in the San Cayetano stope. These fills average 2.4 kg. Hg per. ton. During the period of maximum production at Huitzuco, the ores were sorted in the mine and cobbed into 3-in. pieces, which were treated in Scott furnaces. Large pieces of raw ore are found in the sinter, and it is indicated that both recovery and, costs were not very satisfactory. Recent practice has been to treat the ores in closed retorts made of 10-in. pipes. Because f the presence of combined antimony in the mineral livingstonite (HgS.2Sb2S3) and considerable native sulphur, little or no metallic mercury is recovered in the condensers and a second retorting of the condenser muds is-necessary. This makes the treatment of the ores expensive and tends to low recoveries of mercury. The prin-cipal costs of retorting are, in their relative order: (1) fuel, (2) low recov-ery of mercury, (3) replacement of retort pipes, (4) labor.

Jan 1, 1938