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ENGINEERS AVAILABLE (Under this Beading will lie published notes sent to the Secretary of the Institute by members or other persons introduced by members.) Member,, technical graduate, aged 38, 14 years' experience in engineering, exploration, and management of copper, pyrite, and large iron mines, safety work, professor of mining in large university. Married. Open for position after June 10. No. 205. Member, graduate engineer, aged 44, with over 20 years' experience in connection with large coal and coke operations in different parts of the country, desires position as general superintendent of large coal company, or will take an interest with the management in a smaller company. No. 206.

Jan 5, 1915

By K. Shoji, R. Hogg, L. G. Austin

The flow of dry powders through continuous ball mills has been investigated. Based on a physical model of the system, expressions have been derived which relate the holdup of material in the mill and its variation along the length of the mill to the mill dimensions, speed of rotation, material feed rate, and the mill discharge geometry. Experimental results obtained in a small (4 in.) mill using 3/8-in. steel balls and a feed of silicon carbide particles are in good agreement with the prediction of the model.

Jan 1, 1976

By J. D. Livingston, Bruce Chalmers, R. L. Fleischer, R. S. Davis

INTERACTION of dislocations on intersecting slip planes has long been considered a primary cause of work hardening in metals. Easy glide and low work-hardening rates have been observed experimentally only when single-crystal specimens were oriented so that one slip plane was initially favored. When single-crystal specimens have been oriented so that initially two or more slip planes were equally favored, high initial work-hardening rates have been observed. In a polycrsstalline aggregate, glide on five systems is in general necessary for a crystal to deform in conformity with the change in the shape imposed by the other crystals.* Only a small fraction of the crystals of a polycrystal will be oriented so that two

Jan 1, 1958

By Roland W. Rammler

With oil consumption increasing more rapidly than known reserves in industrial countries, there has been a growing interest in the production of synthetic crude oil. The main starting materials for such production are coal, oil shale and tar sand, all of which occur in enormous quantities in North America. A process sequence suitable for all three of these starting materials incorporates a preliminary retorting step to produce oils for subsequent hydrotreating. For this retorting step, a technique known as the Lurgi-Ruhrgas process has proven highly efficient. The process has been commercially used for the flash carbonization of coal and has also been tested in pilot- plant experiments with oil shale and tar sand.

Jan 1, 1970

By Colin Rae

THE absence of paraffin and other oil hydrocarbons in the soil, although they are concentrated in extensive deposits in some localities, the common distribution of plant remains through many formations that .are not productive for oil, and many other factors, seem to indicate the existence of an intermediate organic compound between the complex plant compounds and the petroleum hydrocarbons; and much evidence points to the humus acids or associated organic compounds, which are probably collected by surface waters and concentrated in certain areas by means of precipitation by electrolytes, which would be contained in sea water or possibly in various inland seas or lakes. PRESENT-DAY EVIDENCE There are many present-day evidences of the association of petroleum with humus acids. Binney, in 1912, made observations without explanations on the peat mosses of Down Holland, England, where he found petroleum being formed by decomposition, in the presence of an infiltration of sea water. The analysis of a typical peat will show its relationship to the humus acids under consideration. SAMPLE 'No. 1, SAMPLE NO. 2, PER CENT. PER CENT. Water : 20.0 29.5 Ash 3.0 3.05 Fiber 47.0 54.95 Humus acids 30:0 12.50 J. D. Haseman and others have noted the association of asphalt and hydrocarbons with the swampy, boggy areas, particularly adjacent to the sea.

Jan 2, 1922

By Lawrence Burkhart, S. B. Joo

A hemispherical, constant volume drop with forced internal circulation was considered as a model approximating a real drop at a similar stage of formation Axially symmetric steady flow within a drop contaminated by surfactants was described by solving the full Navier-Stokes equations written in terms of a meridian plane stream function Rotational flow occurred inside the drop above a computed Reynolds number of 5.8, and the change in interfacial flow caused by imposing a surface-tension gradient at the surface had a significant effect on the internal flow Although the work is quite fundamental in nature, the rotational flow described in the paper is responsible for much of the bulk transport of solute to the interface in hydrometallurgical processes such as solvent extraction.

Jan 1, 1981

At its meeting on February 21, 1933, the Board of Directors the following resolution defining and expressing the policy of the Institute with respect to official participation or action in controversial matters: WHEREAS, the Board of Directors at its last meting passed the following resolution: "The Board of Directors, having been appealed to by several Local Sections for advice concerning the attitude and policy of the Institute relating to the endorsement of candidates for public office, the following statement of policy is formulated:

Jan 1, 1936

By David LeCount Evans

Not only E. B. Mayo but also W. C. Lacy, who apparently urged the preparation of this analysis, is to be commended. Regional thinking of this type is needed to assure future success in the never-ending search for new mineralized and petroliferous districts. As is usually the case, here is a regional study that will be read by the mining geologist alone. It is ironic that several of the trends established in this study have suggested themselves in northern mid-continent, detailed, and regional studies. These, where established, have offered new keys to petroleum exploration and have provided a possible basis for unraveling a number of broad generalities. The oil geologists, active in Colorado, Kansas, and Oklahoma, would find much food for thought in Mr. Mayo's projections.

Jan 6, 1959

At its meeting on February 21, 1933, the Board of Directors passed the following resolution defining and expressing the policy of the Institute with respect to official participation or action in controversial matters: WHEREAS, the Board of Directors at its last meeting passed the following resolution: "The Board of Directors, having been appealed to by several Local Sections for advice concerning the attitude and policy of the Institute relating to the endorsement of candidates for public office, the following statement of

Jan 1, 1938

By John A. S. Dow, Garry G. Lowder

Tapadaa is one of several centers of porphyry copper mineralization in northern Sulawesi. Host rocks are mainly varieties of quartz diorite porphyry. Structural control of mineralization is indicated by elongation of the sulfide system (5 x 1 km) parallel to prominent NW-trending structures, but in detail mineralization is strongly influenced by relative age and lithology. Hydrothermal alteration is characterized by widespread occurrence of advanced argillic assemblages and the presence of sodic rather than potassic alkali feldspar. Propylitic alteration surrounds the mineralized area. Phyllic and advanced argillic alteration occur in structurally controlled zones and in limited pervasive areas. Hypogene copper mineralization develops in rocks with sericite-albite alteration and comprises low total sulfide chalcopyrite-bornite or chalcopyrite-pyrite.

Jan 1, 1978

At its meeting on February 21, 1933, the Board of Directors the following resolution defining and expressing the policy of the Institute with respect to official participation or action in controversial matters: WHEREAS, the Board of Directors at its last meting passed the following resolution: "The Board of Directors, having been appealed to by several Local Sections for advice concerning the attitude and policy of the Institute relating to the endorsement of candidates for public office, the following statement of policy is formulated:

Jan 1, 1934

By James C. Fowler

The use of ground-probing radar as a reflection mapping tool is gaining acceptance in subsurface investigations. This tool may be used to obtain near-surface information useful to geotechnical engineers. Along with the lightweight field equipment now available, radar is being used to obtain information that may impact the safety and production of mining, tunnelling, and excavating operations.

Jan 1, 1982

By J. F. Stiehr, R. L. Sanford, T. L. Myers

This paper summarizes the development of a Directory of Computer Programs Applicable to US Mining Practices and Problems. The directory is funded by the US Bureau of Mines and includes a sampling of computer usage in operating and manufacturing companies, consulting firms, computer companies, research organizations, universities, and various US government agencies. General references to computer applications throughout the mining industry are discussed as well as the availability of programs to interested organizations or individuals.

Jan 9, 1979

No. 364.-Asbestos mine in Canada desires assistant mine superin¬tendent to supervise mining of ore and delivery of same to mill bins. To be successful, applicant should be good organizer and able to get production at right cost; one with experience on steam-shovel rock work preferred. Knowledge of French desirable. Salary $175-$200 per month; permanent position; chance for advancement. Company¬ owned houses available at nominal rental. No. 365.-Research metallographist. Man of commercial experience in alloy steels for position offering opportunity for constructive work over wide range of alloys, with large concern providing ample working facilities. In replying please give full details of training; experience, age and salary desired. No. 366.-Engineer to do surveying and making of mine maps cover¬ing inside development of mine as well as property outside of the-mines. Matter of salary depends on man's experience and efficiency. No: 367.-Engineer, preferably single man to be detailed mostly on mine surveying. Salary to start $130 per month and expenses while on the road.

Jan 2, 1919

By L. J. Erck, T. E. Ban

A discussion of laboratory procedures used to determine pellet quality and to simulate handling and firing conditions. Strength- temperature relationships in pelletizing; effect of chemical additives on agglomeration; and crushing, abrasion, and impact resistance of the pelletized products are discussed with respect to five different iron ore concentrates.

Jan 8, 1953

By C. H. Curtis

The valuable mineral content of the current feed to the Miami concentrator is as follows: copper, 0.7 pct total; molybdenum, 0.01. Flotation of this ore yields a sulphide concentrate containing: chalcocite, 44 pct; molybdenite, 0.5; pyrite, 50.0; insol, 5.5. A combination of potassium ethyl xanthate and pentasol amyl xanthate as collectors, and pine oil as frother, are used in this flotation. Rejection of pyrite is encouraged by holding the amount of collectors used to the minimum consistent with copper recovery and by operating at high alkalinity (equivalent to 0.35-0.40 lb CaO per ton solution of pH 11.0).

Jan 4, 1950

By Leonard P. Colvin

Like all successful American enterprises, the mining industry is constantly trying to increase production, lower costs and improve working conditions. Companies are, of course, intensely interested in new equipment to help them gain these important ends, and one recent development-the mechanical raise climber--contributes to all three goals. Properly used, it increases production, cuts costs and has a number of important safety aspects all of which are the subject of this article.

Jan 1, 1962

By Howland Bancroft

THE writer has observed that some confusion is experienced by many mining engineers in making vertical sections of ore deposits in mining properties which they have examined. Having much examination work calling for the correct interpretation of vein structure and the subsequent platting of the same on sections, it has occurred to the writer that the accompanying diagram may be of use to others who at times may be called upon to prepare numerous sections. For example, a great mass of data on-strike and dip of ore bodies is collected underground in separate

Jan 7, 1914

M. A. Hanna is investigating a nickel prospect near Riddle, Ore. Drilling is under way and a prospect shaft is being put down to obtain samples for metallurgical test work. The deposit is favorably situated for open pit mining. The property had been drilled previously by the USGS and by Freeport Sulphur Co. A $75,000 laboratory pilot plant will begin operations this year to determine if economic beneficiation of a deposit of low grade iron ore, being examined by M. A. Hanna in the Iron River, Mich., district, is possible. Three miles east of Randville 2560 acres of land have been acquired, and drilled, over the last 2 years. The ore is reported to be 34 pat Fe.

Jan 6, 1951

By R. L. Fleischer

IN 1925 a criterion for localized deformation in a single crystal was derived by Taylor and Elam.' They noted that for a single active slip plane the slip plane area is constant, but the direction of the stress with respect to the slip direction changes during deformation so that, when the increase in stress due to this rotation is large enough relative to the work hardening, instability occurs. (By instability is meant continued slip on the active slip plane.) The instability criterion may be written t>dt/d?/m tan2? [1] where t and ? are resolved shear stress and strain, m the Schmid factor for resolving shear stress, and ? is the angle between the slip direction and the axis of tension. The formula points out that regardless of the atomic mechanism involved, for large flow stresses and low work hardening rates, slip on a single plane—once started—should continue. The case of alloying provides a direct possibility of adjusting the parameters in Eq. [I]: As an alloying element is added to a pure metal, the flow stress is raised and the work hardening in easy glide may be either decreased2 or unaltered.3 Since flow stresses in easy glide may rise to the kg/mm2 range for alloy crystals while easy glide slopes may be less than % kg/mm2, 2 it is possible for the inequality to be satisfied. Indeed Garstone and Honeycombe3 report that slip becomes coarser with increasing stress in the easy glide range, where the flow stress would be increasing and the slope would be essentially constant. Another case where high flow stresses and low hardening rates accompany coarse slip is that of quench hardening.4 Maddin and Cottrell report that quenched aluminum crystals display slip markings resembling those of a brass. A similar effect has been observed after irradiation.'

Jan 1, 1960