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By William G. Kegel

Problems involved in putting the gob back underground in modern deep mines we dealt with. In particular, the problems associated with haulage of the gob back to the mine, the blown gob method of dispersion underground, and handling the refuse as slurry are discussed. Some alternative methods of disposal are presented.

Jan 1, 1976

By P. W. Shimer

The purpose of this note is to call attention to a source of error in the determination of graphitic carbon, made by the usual method of solution in hydrochloric acid. Although the method is tedious, because of the necessary treatment of the separated carbon with caustic potassa, alcohol and ether, the text-books seem to give it preference; and it is, perhaps, used more generally than the method of solution in dilute nitric acid. Solution in hydrochloric acid usually gives higher graphitic-carbon results than solution in nitric acid, and many, therefore, consider it more trustworthy, the inference being that the lower results obtained by nitric acid are due to the loss of some of the finely-divided graphite by reason of the oxi-

Jan 1, 1896

By Kichizo Niwa

A LTHOUGH studies on the roasting of ferrous A sulfide have been carried out by several investigators, some disagreements still remain among those results. Schwab and Philinis1 have measured the rate of oxidation by a precise thermobalance and have concluded that the rate is controlled by diffu-

Jan 1, 1958

(This list includes only those who have entered military service within the past month, or whose entry has only recently become known to us; it also includes a few names of those whose titles or assignments have been changed within the month. The last complete list was printed in Bulletin No. 131, November, 1917. A complete Honor List is maintained in the reception room at the office of the Institute.) ADAMS, HENRY, Captain, Asst. to Dept. Engineer, Northeastern Dept. BLAKE, EDWIN T., Captain, Corps of Engineers, U. S. R. CALDER, NORMAN L., Co. A., Y. W. D. Royal Engineers. CAMPBELL, CHARLES W., 2d Lieutenant, 312th Engineers. * See footnote on third page preceding.

Jan 12, 1917

By Donald A. Dahlstrom

Stronger Than Armies This editorial by Dr. Dahlstrom is based on his acceptance speech of the 1976 Robert H. Richards Award-Ed. Many public figures are saying that the United States is facing the most critical period in its history, and many of us would agree. But people have always been saying this, and all of them were right. They were right two centuries ago when it took a revolution to give birth to the Republic; and they were right during our Civil War, Pearl Harbor, the Great Depression, etc.

Jan 6, 1976

By W. L. Hill, W. H. Armiger, S. D. Gooch

The physical properties, chemical behavior under thermal treatment, and fertilizer value of fluorine-containing pseudowavellite (hydrous calcium aluminum phosphate) that occurs as phosphate clay admixed with quartz sand in an extensive deposit near Bartow, Fla., were determined by experiments in laboratory, pilot-plant, and greenhouse. When the mineral was heated at 500°C, 80 pct of the phosphorus became citrate soluble. The heated product, however, deteriorates markedly under moist conditions such as obtain in the soil.

Jan 6, 1950

IRON AND STEEL COMMITTEE. ALBERT SAUVEUR, Chairman. A. A. STEVENSON, Vice-Chairman. HERBERT M. BOYLSTON, Secretary, Abbot Bldg., Cambridge, Mass. John Birkinbine, William Kelly, J. S. Unger, William H. Blauvelt, Charles Kirchhoff, Felix A. Vogel,. James Gayley, Richard Moldenke, Leonard Waldo, Henry D. Hibbard, Joseph W. Richards, William R. Walker, Henry M. Howe, C. F. W. Rys, William R. Webster, Robert W. Hunt, E. Gybbon Spilsbury, Frederick W. Wood: J. E. Johnson, Jr.,

Jan 12, 1913

By J. M. Silliman

Several years ago, having occasion to determine the amount of some very slight atmospheric depressions, I devised and had constructed by a skilful tinsmith the manometer shown in the accompanying drawing. It consists of a cylindrical vessel of tin, 6.6 inches in diameter, through the sides of which, at a distance of about six inches from the top, passes an air-tube D, its upper extremity terminating 3.5 inches from the top. Within the vessel is a combined cylipdrical

Jan 1, 1889

By J. C. Kerkering, J. C. Franklin, T. O. Meyer, R. W. McKibbin

A continuous survey of radon gas was made in two interconnecting stopes in a southwestern U. S. uranium mine to determine how the various phases of the mining cycle affected the radon concentration. The radon was monitored continuously with five detectors. One detector monitored the intake air, one the exhaust air, and three the stope air. The radon concentrations present during slushing, blasting, and exhaust fan shutoff were compared with concentrations on a nonwork day as a base level. Inside the stope, the radon concentration increased about 40% during slushing and 425% after blasting. Intake air radon increased 1600% and the stope air increased 550% while the surface exhaust fan was off.

Jan 1, 1979

By Fred C. Bond

This article is interesting because it deals with the fundamentals of grinding in a novel manner. However, it is somewhat reminiscent of Mark Twain's famous evaluation of science as the production of pounds of conjecture from ounces of fact. Extrapolations abound, and some cases they are treated with a seriousness that is undeserved. Tests should undoubtedly be made of wet grinding at supercritical speeds, using smooth mill lining and mill charges of large grinding balls as well as pebbles. However, the performance predicted in the article needs more qualification than it has received.

Jan 5, 1958

By W. Robert Power

Petrographically these range from true granite and syenite to gabbro and anorthosite. Commercial limestone is any sedimentary rock composed predominantly of the minerals calcite and/or dolomite. Commercial marble is any crystalline rock composed predominantly of calcite, dolomite or serpentine that is capable of taking a polish. Marble comes in a wide variety of color, texture and pattern. Many commercial marbles are unmetamorphosed limestone, to the geologist or petrologist but if they take a polish, are classified as marble.

Jan 6, 1972

By E. B. Thornhill

In this paper on the recovery of mercury as sulphide, from the residues from the amalgamation and cyanide treatment of high-grade ores and concentrates, I will not discuss the many reactions, chemical and other- wise, that take place in the general process, but confine myself more particularly to the methods of recovering the mercury. I submit charts of two amalgamation-barrel charges, Figs. 1 and 2, which are self-explanatory. The flow sheet of the high-grade and the mercury extraction plants is showh in Fig. 3.

Jan 1, 1916

By David S. Butts

The high cost of energy has made many solution mining corporations turn from fuel consuming evaporators to solar energy and solar ponds. The generally held concept of a solar pond is an area enclosed by dikes into which brine is pumped, water evaporated by the sun, and the resulting salts scraped from the bottom of the pond. This paper will show that solar ponding is not simple. It is a science involving six main areas. These areas are (1) land conditions, (2) meteorology, (3) fresh water, (4) accessibility, (5) manpower and (6) mineral resources. Each area is discussed to identify important parameters that must be investigated before the viability of a solar pond complex can be established as a mineral recovery step.

Jan 1, 1985

By R. W. Raymond

THE important question of the metallurgical value of the coals of the Rocky Mountains and the Pacific Coast is to be settled, of course, by practical experiment. Meanwhile; as I have had occasion to point out, the proximate analyses of these coals throws little light upon it, and is, indeed, likely to mislead the metallurgist, if he compares it with the results of similar analyses upon bituminous and semi-bituminous coals. With the view of showing how large a proportion of the material usually classed as." volatile matters " consists of combined water, or oxygen and hydrogen presumably in chemical combination, I have collected a number of ultimate analyses from various sources, in the following tables. The numbered analyses in the first table are as follows

Jan 1, 1874

By Charles Rich, Robert Munson, Leonard Obert

Improved methods of predicting the caving characteristics of ore bodies is discussed. Experiments were conducted at Climax mine, Climax, Colo., on varied rock compositions. The cavability of adjacent areas, as well as seismic energy absorption proved to be good factors in determining cavability. Seismic velocity, core recovery, and rock quality designation (RQD) were found to be not as reliable.

Jan 1, 1977

By Persifor Frazer

There is always a difficulty in assigning limits to the scope of a science or art, and among the dificulties of that kind besetting practical or stratigraphical geology is that of determining what kinds of natural objects shall be considered as the goals of its search. The term mineral, in its broader sense, includes every solid, liquid, or

By Stephen E. Erickson

MORE and more hydrocyclones are being installed in beneficiation plants. This recent rapid increase is of special interest in the history of beneficiation, since development of the hydro- cyclone appears to have swung in a circle. To avoid any chance of confusion, it would be well first to review the accepted definitions. The size of a cyclone is expressed as the diameter of the cylindrical section. Size of the inlet orifice- which may be circular, square, or rectangular- is expressed as a diameter, or as width and length, or as an area (in square inches). The angle of a cyclone is expressed as the total included angle. The overflow or finest classification fraction leaves the cyclone through the vortex finder. The underflow or coarsest classification fraction leaves through the apex opening.

Jan 8, 1957

The primary purpose of the Institute is to advance the technologic and engineering arts embraced by it through inter- change of knowledge. This can best be done by the presentation and discussion of technical papers by its members. Short practical papers are especially welcome. An author should always satisfy himself that his material is of a quality that will be a credit to him and to the Institute. The preparation of a good paper frequently leads to a reorientation of the author's thoughts, and publication contributes much to the professional standing of the author. Members are urged to submit papers presenting the results of their work. Attention to the following suggestions will greatly further the prompt and efficient handling of manuscripts.

Jan 1, 1946

By Gifford Pinchot

The proposition that forest reserves are, from the mining point of view, not only desirable but necessary, is not one which would have received enthusiastic support in. the West a year ago. It is, nevertheless, easily susceptible of proof. A short and simple statement of the facts has seldom failed to carry conviction as to the wisdom of the forest-reservation policy. Hostility to mining interests was never contemplated by the men to whom the forest reserves are chiefly due, and it is most unfortunate that the opposite belief should have obtained wide

Jan 1, 1899

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Jan 1, 1938