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Jan 1, 1941

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 Lloyal O. Bacon

In the spring of 1952 Calumet and Hecla Inc. began a geophysical program near Shullsburg, Wis., in the Wisconsin-Illinois lead-zinc district, to assist the geological and drilling exploration programs. Sphalerite, the ore mineral in this area, occurs with a considerable amount of marcasite. In general the higher the percentage of sphalerite in the ore, the higher the percentage of marcasite; however, there may be mineralized zones high in marcasite but low in sphalerite. Orebodies in general are relatively narrow and elongated.

Feb 1, 1956

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Jan 1, 1938

By K. Osseo-Asare

The thermodynamics of solid-aqueous solution equilibria up to 200°C In the systems Me-NH3 H2 0 (Me=Cu, Ni, Co) are summarized with predominance area diagrams generated with the DIAGRAM computer program. The implications of the diagrams to ammonia hydrometallurgy are discussed.

Jan 1, 1981

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 R. A. MacGregor

The Stanrock mine of Stanrock Uranium Mines Ltd. is located on Quirke Lake in the Elliot Lake area of northern Ontario, about 25 miles north of Lake Huron. The property was developed and brought into production at a rate of 3000 tons of ore per day during the uranium boom of the mid-1950's. The mine workings are from 1200 to 2100 ft below sea level. Mining was done by the room-and-pillar method with 65 to 80% extraction. The plant is located at an elevation of 1400 ft above sea level. The orebodies are conglomeratic beds, 6 to 40 ft in thickness and dipping 5º to 40º. The ore is a quartz pebble conglomerate with a pyritized sericitic matrix. The ore minerals are brannerite, frequently intergrown with anatase or rutile, uraninite, and some monazite and minor coffinite and thucolite. Sulfides constitute 5 to 10% of the ore as pyrite with minor amounts of pyrrhotite, chalcopyrite and galena.

Jan 3, 1969

By Robert J. McNally

There are three primary plant nutrients-nitrogen, phosphorus, and potassium--expressed in any fertilizer compound as percent N, percent P2O5, and percent K20, in that order. This article will be concerned with the first two. The chief source of P205 is phosphate rock. As found in the western states phosphate rock is essentially tricalcium phosphate-calcium fluoride (fluorpatite). As such, it is quite water insoluble. The principal phosphate fertilizer used is single superphosphate, produced by reacting sulfuric acid with phosphate rock in the proper proportions.

Oct 1, 1956

By Pekka S. Särkkä

The method of interactive dimensioning is based on the computation of the loading-deformation curves caused by country rocks on the pillars with numerical methods. The comparable loading-deformation curves of pillars with different shapes are determined with small-scale model tests in a servo-controlled testing machine. The equilibrium points, i.e. the stability of the different pillar-country rock systems are determined by matching these curves adequately scaled. A case from a Finnish mine is presented together with the stoping results.

Jan 1, 1984

Jan 1, 1922

Jan 1, 1951

By Feridun A. Albayrak

Jan 1, 1985

By Mohammad A. Pasha, John T. Atkins

Utah International's Shirley Basin Mine is located in the Southeastern High Plains of Wyoming at an elevation of 7100 ft. The Shirley Basin area is a gently rolling semi-arid land. The uranium ore zone occurs at depths ranging from 270-350 ft below the surface. Overburden consists of poorly consolidated sandstones, siltstones and clays. Underground mining was begun in 1960. Conditions were made difficult by high rates of water inflow and ground support problems. Development of a solution mining or in-situ leaching technique allowed underground operation to be abandoned in 1964. Solution mining provided limited production from 1963 to July 1970. In January, 1969, large scale development of open-pit mining was begun. A 1200 tpd mill went on-stream in March, 1971.

Jan 6, 1973

By J. D. Miller, R. L. Atwood

The structure, properties, and composition of commercial chelating-type copper extractants are examined. Characterization of these extractants was accomplished using organic separation techniques and analytical tools such as NMR and infrared spectroscopy. Results indicate that only the trans isomer of the diphenylhydroxyoxime (LIX 64N) is capable of copper chelation. The effects of structural modification of the extractants on the extraction and stripping reactions are discussed.

Jan 1, 1974

It took the US coal industry 55 years to increase domestic coal production by about 11%-from 568 million tpy in 1920 to today's level of about 630 million tpy. With such a growth record, it would take a few hundred years to double coal production. FEA planners think that it can be doubled in 10 years. "With all the obstacles continuously imposed on coal, the industry's real problem is not growth but survival," says Ray Albrechtsen, board chairman of Mountain States Resources Corp., and "we should consider ourselves lucky if, by 1985, the coal industry won't have been legislated and regulated out of existence."

Jan 5, 1975

By B. S. Butler

It is suggested that at high temperatures both sulfur and iron combine with oxygen. Iron may precipitate at the high temperatures as the oxides of iron, and sulfur also in combination with oxygen as the low solubility sulfates of barium, strontium, calcium, and potassium (alunite). At lower temperature the precipitation results from change of sulfate sulfur to sulfide sulfur, and the iron precipitates as the sulfide.

Oct 1, 1956

By Randolph Specht

A two year study was made of the waste disposal of the pebble rock phosphate industry. Solid slimes are impounded in large settling areas and the process water is re-used. Clear effluent was not found to be toxic to fish or animal life in field tests or in controlled experiments.

Jan 7, 1950

By Kenneth A. Grace

Jan 1, 1985

By S. G. Valentine

Blast-furnace blowing engines are broadly of two main types: either steam - or gas-driven reciprocating engines, or turbine-driven rotary engines.

Jan 1, 1915

By Ta M. Li

A record 340 senior students with majors in mining and mineral engineering from 21 shcools in the US may be expected to enter a manpower-hungry mineral industry in 1975. While starting salaries may have been the deciding factor in job selection in the past, 1975 graduates will find salaries almost the same in most mining sectors. Meanwhile, the survival prospects of various mineral engineering schools had the usual ups and downs in 1974, but tightening state budgets could still take a toll in reducing the number of schools offering mineral engineering degrees. Two such schools on the endangered list include Montana College of Mineral Science in Butte, Mont., and the College of Mines, University of Idaho, in Moscow, Idaho.

Jan 3, 1975