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By William E. Ford, Edward Salisbury Dana

The Niobates (Columbates) and Tantalates are chiefly salts of metaniobic and metatantalic acid, RNb2O6 and RTa2O6; also in part Pyroniobates, R2Nb2O7, etc. Titanium is prominent in a number of the species, which are hence intermediate between the niobates and titanates. Niobium and tanta¬lum also enter into the composition of a few rare silicates, as wöhlerite, låvenite, etc. The following groups may be mentioned: The isometric PYROCHLORE GROUP, including pyrochlore, microlite, etc. The tetragonal FERGUSONITE Group, including fergusonite and sipylite. The orthorhombic COLUMBITE Group, including columbite and tantalite. Also the orthorhombic SAMARSKITE GROUP, including yttrotantalite, samarskite, and ånnerodite. The species belonging in this class are for the most part rare, and are hence but briefly described.

Jan 1, 1922

By Atsushi Watanabe

Japanese Operations Research Committee for Mining Industry is one of the committees in The Union of Japanese Scientists and Engineers. Members of the committee are Dowa Mining, Furukawa Mining, Mitsubishi Metal Mining, Mitsui Mining and Smelting, Nippon Mining and Sumitomo Metal Mining. This paper is an annotated summary of study reports of the committee.

Jan 1, 1969

By S. H. Ash

Foreman remains key man in any safety program, as men attracted to the industry must be trained in safety thinking. Diesel engines underground aid safety and widespread use of roof bolting is reflected in reduction of roof-fall fatalities.

Jan 2, 1953

By C. A. Shook, W. H. W. Husband, D. B. Haas

Although previous studies l,2,3 have been made, no correlations for pressure drop have been proposed. This is probably because severe particle breakage occurred and pressure drops changed substantially with time. A quantitative statement of the relationship of pressure drop to the parameters of the system is desirable for lignite since, unlike higher rank coals, lignite slurries are thixotropic. The present investigation was undertaken to quantify the pipeline behavior and required continuous monitoring of pressure drop and size distribution.

Jan 2, 1979

The saying that a "prophet" is without honor in his own country does not always hold true, as is shown by the following from one of the local papers, which appeared under the above heading: "Edwin Ludlow, for more than seven-years vice-president of the Le-high Coal.& Navigation Co., with headquarters in Lansford, has resigned, to take effect July 1, when he will take up his residence in New York and engage as a consulting engineer. Mr. Ludlow, during the incumbency of his present position, has demonstrated his efficiency as an engineer and general manager in many directions, notable among which are the almost perfect methods in practice in the inside workings of the several operations under his charge and the erection of the most complete, most practical and most commodious breakers for the preparation of the mine product for market. In addition, his relations with organized labor have been cordial and his dealings with its representatives have been invariably based upon the principle of fair play."

Jan 7, 1919

MANY members of the National Societies died in service overseas during the World War. No memorial to these engineers has been set up but a unique and interesting suggestion has been made. While Edward Dean Adams, Fellow of the American Society of Civil Engineers, and Associate of the Ameri-can Institute of Electrical Engineers, ,vas in Belgium last June as delegate of the National Societies, En-gineering Foundation, and Engineering Societies

Jan 12, 1927

By T. S. Maio, J. G. Mansanti

In 1978, Ozark Lead Co. made the decision to expand the capacity of its mine/mill complex by 33%. The objectives of the expansion were to increase mine production capacity by 1.8 kt/d (2000 stpd), increase lead metal production by 21.8 kt/a (24,000 stpy), and to construct new facilities and modify existing equipment to accommodate increased production. This paper gives a brief explanation of the equipment installed and the overall production and metallurgical benefits realized from this expansion. The expansion was completed in the second half of 1980 with all equipment debugging and fine tuning completed by the first quarter of 1981. Concentrator modifications and improvements were basically restricted to four areas: materials handling, automation of the mill grinding circuit, increased flotation capacity, and concentrate dewatering.

Jan 1, 1985

By R. J. Lytle

Geophysical exploration for engineering purposes is conducted to decrease the risk in encountering site uncertainties. Such studies are needed in construction of underground facilities. Current responsibilities, opportunities and challenges for those with geophysical expertise are defined. These include: replacing the squiggly line format, developing verification sites for method evaluations, applying knowledge engineering and assuming responsibility for crucial national problems involving rock mechanics expertise.

Jan 1, 1982

Jan 1, 1912

By J. B. Hiskey

Heap leaching has in recent years been established as an important processing alternative for gold and silver. Currently, heap leaching accounts for about 25% of primary mine produced gold and 10% of primary silver. This paper reviews gold and silver heap leaching practice and surveys major operations in the United States.

Jan 1, 1984

By L. A. Hanson

Jan 1, 1964

Howe Memorial Lecture The Howe Memorial Lecture, in memory of Henry Marion Howe, Past President of the Institute, was authorized in April, 1923, as an annual address to be delivered by invitation under the auspices of the Institute by an individual of recognized and outstanding attainment in the science and -practice of iron and steel metallurgy- or-metallography, chosen -by-the Board-of Directors upon recommendation of the Iron and Steel Division. The following were the Howe lectures and lecturers for the years indicated 1924 What is Steel'., By Albert Sauveur.

Jan 1, 1938

By T. Chen

One of the limitations of the 3-dimensional Lerchs-Grossmann pit optimisation algorithm has been the difficulty in calculating an optimum pit with variable wall slopes. The difficulties have been related to establishing various wall slopes without changing the sizes of the blocks used in the normal computation, but still retaining an optimum solution.

Jan 1, 1977

Jan 1, 1961

S. F. EMMONS RESEARCH FELLOWSHIP. The movement was started by a number of the friends and admirers of the late S. F. Emmons, Economic Geologist of the United States Geological Survey, to perpetuate his name through a fellowship to be known as the " S. F. Emmons Research Fellowship," and they have succeeded in raising some $13,000 for the purpose of carrying on research work in economic geology. The Committee in charge of this Memorial Fund has succeeded in obtaining the co-operation of Professors Kemp, of Columbia, Irving, of Yale, and Lindgren, of Massachusetts Institute of Technology, in the administration of this fellowship. These three gentlemen are respectively geologists of the institutions mentioned and are exceptionally qualified to determine in what direction the fund can be best administered. It is hoped that additional contributions will be forthcoming from many who have heard of this movement. Subscriptions are invited and may be sent to any one of these gentlemen, or to Benjamin B. Lawrence, Treasurer, No. 60 Wall Street, New York City.

Jan 11, 1913

By Paul Levin

A coal preparation plant built with conventional materials only might be able to do an efficient job of preparing coal, but its maintenance costs would be high and emergency shutdowns frequent. To remedy this situation special materials are being used, either in original plant construction or for replacement of conventional materials. The special materials vary from high-strength and abrasion-resisting steels and stainless steel alloys to ceramics. They include hard surfacing welding rods, rubber refractories and some of the newer plastics, the merits of which are cited by the author. A coal preparation plant, limited strictly to the use of conventional materials-for example, mild steel, cast iron and ordinary rubber-could, no doubt, do an efficient job of preparing coal, but the high cost of maintenance and increasingly frequent emergency outages would soon force the operator to seek relief by introducing special materials such as alloyed steels, oil-resistant rubbers and hard-surfacing welding rods.

Jan 6, 1964

By Duane E. Eubanks, David B. McDonald

The anticipated growth of western coal production over the next decade is expected to add approximately 274.3 million t/y (302.4 million stpy) to US capacity. The increased output, coming from both new mines and expansion of existing facilities, promises to bring with it a new set of problems for mine planners.

Jan 8, 1976

By S. K. Kawatra, R. A. Seitz

The use of inferential particle sizing for closed wet grinding circuit control has been practiced for several years. This paper presents a review of some inferential sizing equations developed for pilot and industrial plants using regression analysis. An analytical development is then presented showing how the general inferential sizing model arises from the nature of the classifier model. The relation between the general sizing model and the individual equations is then discussed.

Jan 1, 1984

By T. Egleston

THERE has always been a-theory among those working placer mines that gold is both found " rusty," and becomes so under treatment, by which they mean, not that gold becomes coated with oxide of gold, bat that it is either coated superficially or alloyed with sortie substanee 'which prevents the ,contact with mercury, and thus precludes the possibility of amalgamation. To such conditions of the

Jan 1, 1881

By Karl D. Libsch, Modesto E. Erneta

Both battery design and environmental pressures are forcing the secondary lead industry to consider new and different processes. Trends in battery design are making normal decasing increasingly difficult. Lead in air, sulfur dioxides, and solid/liquid waste heavy metal restrictions are tightening. There is no clearly defined industry trend toward a given process, but it is clear that plants will be larger, less labor-intensive, and automated.

Jan 1, 1977