Search Documents

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

By Sam Tour

SOME years ago, the writer described heat checks or thermal. cracks that occur in die-casting dies.1 The life of dies was considered in relation to the casting temperature, the material used for the die, and the heat to be absorbed by the die per unit volume of casting made. The mech-anism of the action that results in thermal failure of dies was described. In the present paper the writer proposes to describe some additional observations in regard to heat checking, make one or two suggestions as to the method or methods for further attack of the problem, and give the results obtained on some work carried out along these lines.

Jan 1, 1934

By R. E. Collom

VARIOUS chapters already written in the history of development of the North Dome of Kettleman Hills are monotonously identical in the one underlying theme of conservation of oil and gas. Discovered on Oct. 4, 1928, by Milham Exploration Co. with its wildcat Elliot No. 1, the field has been subjected to practically every modern form of produc-tion restraint in the name of conservation. The record thus far developed shows that conservation was had for a time, at a price; and that unitiza-tion must he blessed by single ownership or 100 per cent participation to be effective. In fact, incomplete unitization places a heavy handicap upon its participants in the competitive development that follows.

Jan 1, 1937

By H. R. Hardy

The study of the mechanical properties of geologic materials was initiated in the Mining Research Section of the Fuels and Mining Practice Division in 1951 as part of a fundamental study of ground stress in Canadian coal mines.1 Early in the investigation of the mechanical properties of geologic materials, however, it was realized that the test results are influenced by the rate and the duration of loading. For this reason, laboratory investigations2,3 were undertaken to study the effect of long-period uniaxial stress on the deformation and failure properties of these materials. A literature survey indicated that work on the time-dependent properties of geologic materials had been very limited in the past.

Jan 1, 1965

By E. K. Olson

Eagle Mountain mine of Kaiser Steel Corp. began production in 1947 when the direct shipping ore contained 51-56% Fe. The high grade, wide ore face and low stripping ratio ores were rapidly depleted and Eagle Mountain required processing plants for upgrading and more efficient mining equipment. During 1970-71 total annual pit tonnage averaged 56 million tons of material ranking the Eagle Mountain Mine as the fourth largest in the country. Ore production averaged 12.5 million tons requiring a stripping ratio of 3.5: 1. During this period mining activities were scheduled for a three-shift, seven-day operation. The present mining rate is about 30 million tpy on a two-shift, five-day schedule.

Jan 12, 1972

By Magnus Troilius

The heat-calculations of gas-analyses involve cumbrous multiplications, which are apt to lead into errors. The foliowing tables and formulae have been found useful as facilitating such calculations, and therefore I hope that they will be of interest to some of the members. By "heat-unit" will, in the following, be understood the amount of heat required to raise the temperature of 1 kilogram of water l° Cent. All the tables refer to cubic meters at O0 and 760 mm. pressure. The following gas is chosen as an example: C02, - 4.0 vol. per cent. co, = 20.0 " CHI, - 3.5 " H, - 7.0 " N, - 65.5 " " 100.0

Jan 1, 1884

By H. T. Wyatt, A. S. Baptie

The Ten Section field is approximately 10 miles southwest of Bakers-field, Kern County, Calif. (Fig. 1). There is no surface evidence of the existence of the Ten Section structure, which subsurface exploration has shown to be a gently folded, anticlinal dome. Regionally, this field occurs as a fold in the deeper beds of the gently rolling floor of the San Joaquin Valley. It is on the easterly slope of the valley, its position with relation to the axis of this syncline not having been determined. The field was discovered by Shell Oil Co. with the completion of well Stevens A-l, on June 2, 1936, at a depth of 7888 ft. The location for this

Jan 1, 1938

By Ned Kuenhold

AN equipment manufacturer swallows a bitter pill when he sees his machinery improperly in- stalled and not used to the full potential. This frequently happens with vibrating screens. Screens can be classified according to the path of vibration imparted to the screen surface. On this basis there are: 1) vertical circle or modified circle throw, 2) horizontal circle or modified circle throw, 3) vertical linear reciprocation, 4) tilted linear reciprocation, and 5) horizontal linear reciprocation. The most versatile vibration for medium to coarse sizing is generally conceded to be the vertical circle produced by an eccentric or unbalanced shaft, but other types of vibration may be more suitable for certain screening operations, particularly in the finer sizes.

Jan 6, 1957

By Phillip A. Stoll, Young Ku Yoon

ThE deterioration of the magnetic properties of silicon-steel core materials during service (magnetic aging) is quite undesirable. Although some information about the effects of impurity elements on magnetic properties is available, 1,2 magnetic aging that occurs at low temperatures has not been extensively studied. Moreover, the microscopic techniques used by earlier workers were not suitable for study of fine metastable phases that are precipitated at relatively low temperatures. Recently, several investigators3,4 successfully used transmission electron microscopy in the study of low-temperature precipitation in Fe-C, Fe-N, and Fe-Mn-C alloys. To investigate metallurgical factors that affect magnetic properties after aging, the microstruc-tures of steels having different magnetic-aging

Jan 1, 1964

By Sam Tour

SOME years ago, the writer described heat checks or thermal cracks that occur in die-casting dies.1 The life of dies was considered in relation to the casting temperature, the material used for the die, and the heat to be absorbed by the die per unit volume of casting made. The mech-anism of the action that results in thermal failure of dies was described. In the present paper the writer proposes to describe some additional observations in regard to heat checking, make one or two suggestions as to the method or methods for further attack of the problem, and give the results obtained on some work carried out along these lines.

Jan 1, 1934

By D. B. Grove

THE heavy media separation process plays an outstanding role in the concentration of 4000 tons of zinc ore per day at the Mascot mill of the American Zinc Co. of Tennessee. Of the total tonnage, 72 pct is treated in the heavy media separation plant to reject 56 pct of the ore as a coarse tailing, which has a ready market. Concentrates from this separation are beneficiated further by jigging and flotation. Approximately 25 pct of the total zinc concentrate production is made in the jig mill. Jig tailings are ground and pumped to the flotation circuit where the balance of the production is made. Fig. 1 shows a generalized flowsheet of the mill.

Jan 8, 1951

Papers in Classes A-Metal Mining, B-Milling and Concentration, H-Indus¬trial Minerals, and I-Mining Geology are distributed in MINING TECHNOLOGY, which is issued every other month. Papers in Classes C-Iron and Steel Division, D¬-Nonferrous Metallurgy and E-Institute of Metals Division are distributed in METALS TECHNOLOGY, which is issued twice quarterly. Papers in Class G-Pe¬troleum Division are distributed in PE¬TROLEUM TECHNOLOGY, which is issued every other month. TECHNICAL PUBLICA¬TIONS in Classes F-Coal Division, J¬-Mineral Industry Education Division, K¬-Mining Administration, and 1-Geophysics, are issued as separate pamphlets. Contributions are papers that when printed or mimeographed are available but only on request.

Jan 1, 1943

By Horace V. Winchell

The St. Helens mining-district, indicated in sketch-map, Fig. 1, is chiefly in Townships 9 and 10 North, Ranges 5 and 6 East of the Willamette meridian, in Skamania county, Wash. There is no railroad or even a wagon-road at present connecting it with any base of supplies; access is usually by wagon-road for about 50 miles from the town of Castle Rock to Spirit lake, and from that point by pony-trail from 6 to 10 miles farther. History. Nearly 20 years ago two German farmers, totally inexperienced in prospecting, penetrated this region upon a hunting-and fishing-trip. Their attention was drawn to numerous joints and crevices filled with black, glistening tourmaline, and con-

Jan 1, 1913

Bellows Connector Fabricated of chemically inert Teflon, the new bellows type connector has many pipe line applications where vibration, expansion and electrolysis exist in the handling of corrosive liquids or gases and solvents. The new connector is electrically non-conductive, flexible even at 94°F and as strong as 480°F as at 70°F, according to the manufacturer. This bellows connector serves as a [ ] vibration dampener as well as an expansion joint and connects misaligned couplings and insulates flanges electrically. End flanges of the joint are French-type envelope gaskets made integral with the joint for easy assembly between companion flanges and a tight, leak-proof seal on installation. Circle No. 1

Jan 1, 1952

By M. N. Nabighian, J. R. Odekirk, D. M. Hausen

Preliminary investigations based on the concept of cross-power indicate that quantitative volume percentages of minerals, including quartz, orthoclase, plagioclase, fluorite, and chalcopyrite can be obtained by X-ray diffraction analysis. Pulverized samples are scanned from 4° to 65°, 2e, using a Norelco diffractometer, with the output recorded on a punched tape at 40 intervals per degree, 29. Errors from crystal orientation are minimized by (1) gridded surface packing, (2) sample spinning, and (3) quantitative measurement of all major diffraction peaks. Computer programming enables rapid quantitative evaluation of X-ray diffraction data. Results to date indicate that most minerals analyses can be performed within an accuracy of ±2%. Metallurgical applications include analysis of various flotation concentrates and tailings.

Jan 1, 1973

By H. P. Allen

THE Achotla mill of the Cia. Minera de Peñoles is of special interest in that it is one of the few still employing the chloridization process. The ore milled comes from the Suriana mine and consists of both oxide and sulphide, from neither of which can the gold or silver be extracted by a simple cyanide treatment. The mill was built in 1927, after several years of study in the development of the process1, and operated from December of that year until October 1930. Operations were resumed in February 1935, and have been continuous since, treating approximately 5000 tons per month, while the mine is getting up to full tonnage of 6500 tons per month.

Jan 1, 1937

By William E. Ford, Edward Salisbury Dana

The NATIVE ELEMENTS are divided into the two distinct sections of the Metals and the Non-metals, and these are connected by the transition class of the Semi-metals. The distinction between them as regards physical characters and chemical relations has already been given (Art. 453). The only non-metals present among minerals are carbon, sulphur, and selenium; the last, in one of its allotropic forms, is closely related to the semi-metal tellurium. The native semi-metals form a distinct group by themselves, since all crystallize in the rhombohedra1 class of the hexagonal system with a fundamental angle differing only a few degrees from 90°, as shown in the following list :

Jan 1, 1922

By Luis Toron, Salvador Cortes-Obregon

THE Oaxaca coal fields, shown in Fig. 1, are located in the Alta Mixteca region in the states of Oaxaca, Puebla, and Guerrero. Known outcrops are scattered over 3125 square miles. It is probable that further exploration will reveal a more extensive area of deposits. The region is of great importance to Mexico, as at present the only sources of coal are the fields near the U. S. border. Steel mills are also located in the North, and finished products must travel 600 to 800 miles to the area of consumption in central Mexico. The oaxaca coal, only 120 miles south of Mexico, D.F., lies close to several iron ore deposits. If this

Jan 1, 1955

By Augustus Locke

THERE are three matters related to ore-hunting which I wish especially to discuss here: first, the paucity of the special writings applying to it; second, the failure of scientists to concern them-selves importantly with it; and, third, resting on these conditions, certain possible activities for economic geologists. First, as to the writings. Geological papers. are being produced in the United States alone at the rate of 10 to 12 shelf-feet per year.1 But papers specifically for the ore-hunter would go in a slim, annual pamphlet; all that have ever been written would go in a briefcase. The art of technical ore-hunting-geology conceived as a guide to ore-has only a scant literature.

Jan 4, 1922

By W. M. Duncan, F. S. Kendorski, C. V. Jude

After shotcrete had been in use for a short time al the Climax Mine of the Climax Molybdenum Co., Climax, Colo., it was noted that regular longhole undercutting blasts would severely damage or detach slusher drift shotcrete linings. If this were to be a usual occurrence, the widespread application of shotcrete would have to be reexamined or abandoned. Concrete drift linings are affected less by blasting because of occasional significant gaps between the placed concrete and rock and the greater thickness of poured-in-place linings. Research Project Organized A research project was organized to determine: 1) the seriousness of the problem, 2) more complete in-use shotcrete strength data, and 3) possible solutions.

Jan 12, 1973