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By H. Conrad, K. Janowski, G. Stone

The available data on the dynamics of plastic flow of sapphire indicate that the deformation rate in the temperature range .from 900° to 1700°C can be expressed either as A number of investigators1-10 have established that sapphire deforms plastically above 900°C, the most common mode of deformation being slip on the basal plane in the [1120] direction. Under certain conditions and at temperatures above 1500°C, slip

Jan 1, 1965

Jan 1, 1905

We wish to congratulate the authors on a fine presentation of a difficult and interesting problem. We fully support the findings that liquid or even mushy center reduction has no place in the production of quality steels. We also agree with the findings, or implications, that internal bar quality is not made in the rolling stands, but in the caster. This is the main reason why Inland caster exclusively uses the submerged casting technique after a few months of familiarization with open casting. The metallurgical advantages of combining in-line reduction with a caster are actually indirect. The use of submerged casting and refining powder permits casting of fine grained aluminum killed steels without resorting to expensive grain refiners and cuts down or eliminates reoxidation during casting. Immersion of a snorkel into a small mold may lead to several operating difficulties. Hence, the presence of in-line reduction enables the section to be cast into a large mold, at high output rates, while obtaining some product size flexibility. The capital and operating costs of a caster-- in-line mill are lower than those of the traditional installation with a separate reheating furnace and billet mill. Admittedly, in-line reduction represents an additional challenge to the steelmaker, maintenance man, and metallurgist.

Jan 1, 1972

By John F. Barkley, J. W. Woomer, H. F. Yancey, H. B. Charmbury

The coal picture in 1955 was much brighter than in 1954, when the tonnage produced dropped to the 1939 level. Bituminous coal and lignite production are expected to approach 465 million tons, against 392 million tons in 1954, an increase of about 19 pct. On the other hand, the production of anthracite declined about 7 pct to some 25 million tons. There was marked improvement in coal consumption in all industrial lines except railroads. At the end of November 1955 the largest consumer, electric power utilities, had used about 126 million tons, an increase of some 22 million tons over the previous year. Coke-oven consumption increased about 19 million tons and coal coked in beehive ovens increased about 1.5 million tons, due to heavy coke

Feb 1, 1956

By James W. Clark, William C. Dixon, Kevin L. Wiley, Thomas R. Couzens

This paper is a description of certain geologic aspects of the Inspiration mining operation. It is not a geologic description of the Inspiration deposit nor an exposition of all the geologic work. Involved in the development and exploitation of the deposit. A few specific examples of the application of geology and geostatistics to the mining process are given to illustrate the progress that has been made in making the Inspiration Mine more efficient and cost effective, and a statement of the philosophy of geologic applications is offered.

Jan 1, 1985

By D. Lum

The limestone resources of Hawaii are derived chiefly from emerged fringing coral reef and coastal dune deposits of Pleistocene age. These deposits are most abun¬dant on the island of Oahu and other older islands and least abundant on the island of Hawaii, the youngest. Their origin and depositional environment were influenced by glacio-eustatic rising and falling of sea levels during Pleis¬tocene time. Dredged reef limestone deposits from two deep-water harbor projects have provided additional re¬sources. Limestone uses include cement and lime manufac¬turing, concrete sand and aggregate, road base material, beach sand replenishment, agricultural lime, and golf course construction.

Jan 1, 1984

By John J. Childress, Russell L. Cook

Stringent environmental regulations, which have limited the use of sludge ponds, coupled with the economic incentive to clean more coal or to add fine coal cleaning additions to existing preparation plants have increased the use of static thickeners in preparation plants. The Lamella Gravity Settler, sometimes designated Lamella Thickener, is a shallow depth sedimentation device which has been applied in a variety of industrial process and wastewater control projects in place of the conventional raked thickeners. This paper presents the theory and design of the Lamella Thickener, as well as describing the operating results from several full scale installations in a variety of Appalachian preparation plants.

Jan 1, 1979

By R. T. Carter

THE phase behavior of a number of binary systems consisting of paraffin hydro-carbons has been determined in recent years. In addition, the composition of the coexisting phases of mixtures of crude oil and natural gas has been investigated.1 However, the latter study did not include information concerning the influence of the concentration of a component upon its distribution between two coexisting phases. Owing to the paucity of such information it was considered desirable to investigate in some detail the composition of the co-existing phases in the methane-propane-n-pentane system throughout the greater part of the two-phase region at a tempera-ture of 100°F. Information of this nature also permits the establishment of the critical behavior of this ternary system.

Jan 1, 1940

By E. V. Manlapig, David J. Spottiswood

In recent years great advances in the automatic control of flotation plants have been made, mainly due to the development of reliable sensing instruments to monitor process performance and the development of an adequate understanding of system responses to process disturbances. Some of the control strategies used in flotation plants which apply computer control are presented here. These schemes, which involve the control of collector; depressant, frother, and air and pulp level, are analyzed with respect to their control objectives, control variables, and the instrumentation involved. The knowledge gained in understanding these strategies may be applied in the dew and implementation of control system in other concentrators.

Jan 1, 1981

By W. T. Jr. Thom

INTEREST naturally attaches to fissuring and subsidence of the earth's surface, whatever the cause may be, and the induced movement and fissuring of the impervious strata overlying an oil sand is of even greater practical importance because of its bearing upon the recoverability of the portion of the oil not already extracted or extractable by ordinary production methods. It is probably true that significant ground movement induced by oil production occurs only in oil fields in relatively young formations, where the oil comes from incoherent or only slightly cemented sands and oil-soaked clays, but inasmuch as a great proportion of our "gusher" wells produce from "running" sands and yield a large part of the total oil output, it seems worth while to make an effort to inspire the collection and recording of data indicating the nature and magnitude of oil-field subsidence, both surface and subsurface.

Jan 1, 1927

By Ta M. Li

In Gila County, Ariz., the Jaquays Mining Co. still finds the mining of asbestos a worthwhile and economical venture. At a time when domestic productive capacity is being reduced because of rapidly rising costs and tough environmental dust standards, this firm has dramatically brought its mine and mill operation into full productive capacity and compliance with both Federal and State regulations. Jaquay's Mining Corp. owns four underground mines in the Tonto National Forest, located approximately 32 miles north of the Globe-Miami District in Arizona. Only one mine, the El Dorado, is presently active. It mines an estimated 45,000 tpy of ore and waste. From this figure about 3000 tpy of fiber (No. one crude to Grade 4T) and fiberized shorts (No, seven) are recovered at the firm's mill, located in Globe, Ariz. Based on current ore reserves, the El Dorado mine has an estimated life between 15 to 17 years, assuming current mining rates and stable market conditions.

Jan 3, 1975

By Alfred Weiss

The business world of tomorrow will experience a major change in its data communication systems, with the mineral industry being among those to feel the greatest impact of this change. This development can be expected to occur over the next two decades at a steadily increasing tempo. One major factor prompting this transformation is the fact that technological knowledge is doubling approximately every five years. Moreover, industry is becoming more and more dependent upon the flow and processing of information in its long-range planning, while government requirements and regulations demand increasingly detailed and precise information on plant operations.

Jan 1, 1971

By William Hamilton Merritt

Since 1880 the occurrence of gold-ore has been known in the Lake of the Woods district. In 1879 the writer examined a so-called silver-location in the lake. More recent developments have extended, south and east, to the Rainy lake and along the Seine river, which flows from the northeast into the Rainy lake. The gold occurs in quartz-veins in the Huronian series. These Huronian rocks occur in belts in the Laurentian; the latter being the predominant formation in the eastern part of Ontario.

Jan 1, 1897

By H. M. Chance M

The following tables have been compiled from the annual reports of the Inspectors of Mines, to determine the percentages of fatal and non-fatal casualties from roof-falls and explosions of fire-damp. As we cannot assume that every accident has teen recorded by the inspectors ; as many casualties terminating fatally after the lapse of a considerable period, are inevitably recorded as " non-fatal;" and as clerical errors may have crept into the compilation,* the figures of these tables cannot be considered absolutely correct, but the summary is sufficiently reliable to show the features I wish to differentiate. Under the heading " Miscellaneous" are included all accidents not directly attributable to explosions of fire-damp, roof-falls or fails of coal. Prominent among the numerous causes included under this head are premature or delayed explosion of blasts, accidental explosion of powder or cartridges, accidents from mine cam, falls in shafts, machine accidents, sliding of loose coal in pitching breasts, suffoca tion by choke-damp, etc., comprising in all 48 per cent. of the total number of casualties.

Jan 1, 1882

By W. J. Keep

Almost without exception, writers on the subject say that sulphur in cast-iron will cause it to be white, and is in every way injurious. All founders believe that a small amount of sulphur in the fuel will work great damage, and that if any castings crack, or if anything out of the general run occurs, it may be charged to sulphur in the fuel. Fuel rarely contains more than 1 per cent. of sulphur, and if this can produce so marked an effect, one would suppose it an easy matter to introduce sulphur into cast-iron, so as to produce castings containing different desired percentages of sulphur. We have be-

Jan 1, 1894

By Robert H. Merrill, Raymond M. Stateham

Recently, the Denver Mining Research Center of the U.S. Bureau of Mines began tests to detect hazardous or potentially hazardous conditions in or around mines with infrared measurement devices. Among the many potential uses of infrared detection techniques are the location of misfires, underground mine fires, combustion in waste dumps, underground water courses and loose rock. However, the primary emphasis has been placed upon the detection of loose rock in roofs, pillars and faces in underground mines. The rock along the edge of an underground opening is subject to two temperature environments: the temperature of the air in the opening, and the temperature of the rock surrounding the opening. Assuming that the rock on the edge of the opening is solid, the rock will reach an equilibrium temperature that depends upon the temperature and flow of the air, the thermal conductivity of the rock and its ambient temperature. Presume that a loose rock exists among this solid rock; because there is a temperature barrier, to some extent, between the loose and the solid, the loose rock will be affected more than the solid rock by the temperature of the air. Therefore, depending upon the temperature differences between the rock and the air, the loose will be warmer or cooler than the solid.

Jan 1, 1970

By H. M. Chance

Asst. Geologist, Pennsylvania Geological Survey THE following tables have been compiled from the annual reports of the Inspectors of Mines, to determine the percentages of fatal and non-fatal casualties from roof-falls and explosions of fire-damp. As we cannot assume that every accident has been recorded by the inspectors; as many casualties terminating fatally after the lapse of a considerable period, are inevitably recorded as "non-fatal;" and as clerical errors may have crept into the compilation,* the figures of these tables cannot be considered absolutely correct, but the summary is sufficiently reliable to show the features I wish to differentiate. Under the heading a Miscellaneous" are included all accidents not directly attributable to explosions of fire-damp, roof-falls or falls of coal. Prominent among the numerous causes included under this head are premature or delayed explosion of blasts, accidental explosion of powder or cartridges, accidents from mine cars, falls in shafts, machine accidents, sliding of loose coal in pitching breasts, sltffouration by choke-damp, etc., comprising in all 48 per cent of the total number of casualties. * Compiled by Mr. Maxwell Chapman

Jan 1, 1882

By R. W. Jigins

OPERATIONS of the Braden Copper Co. are in the Chilean Andes, southeast of Santiago. Most remote of the company communities is Sewell, a town of 12,000 people, 7000 ft above sea level at the junction of the Coya and Teniente rivers. Four miles down the Coya River is the smelter town of Caletones, elevation 4500 ft, with a population of about 3000. At the junction of the Coya and Cachapoal rivers 24 miles below Sewell is Coya, eleva- tion 2500 ft, location of the company's two hydro- electric plants. The principal accounting offices; steel, iron, and brass foundries; railroad shops; and major mechanical repair and fabricating shops are at Rancagua in the central Chilean valley, 44 miles from Sewell. The company owned narrow-gage railroad connects with the Chilean national railroad at Rancagua and above Coya is the only modern means of travel. El Teniente mine at Sewell is the largest under- ground copper mine in the world. The mill, at the portal of the main tunnel, has a capacity of 34,000 tons of crude ore daily, although production is lower during the winter beacause of electric power restrictions. When operating at capacity the mill produces 2000 tpd of copper concentrates and 32,000 tpd of tailings. Tonnage of tailings is equivalent to about 100,000 tons of pulp at normal water to solid ratio.

Jan 10, 1957

By Peter Kos

Since advances in the understanding of gravity thickening reflects the development of knowledge about suspensions themselves, the paper starts with the discussion of flocculent and nonflocculent suspensions. The properties of flocculent suspensions and their behavior in different concentration regions (zone settling, channelling, compression) are defined and discussed. In the main portion of the paper, the behavior of flocculent and nonflocculent suspensions during batch as well as continuous thickening, is presented, together with a brief review of the gravity thickening theories and sizing methods. The classical as well as the most recently developed methods are presented and their use and limitations are discussed.

Jan 1, 1980

By E. Northcott, I. M. LeBaron

Before describing the electrostatic processing of feldspar, it might be well to review some of the basic definitions and terminology of feldspars. The feldspar minerals constitute a group of alumino-silicates of potassium, sodium, and calcium. Barium feldspar sometimes occurs naturally but is very rare. Hardness varies between 6 and 6.5 and specific gravity between 2.5 and 2.8. Color is generally white or pale shades of red, yellow, or green. The approximate chemical composition of the principal feldspars is given in Table I. The albite (sodium aluminum silicate) and an orthite (calcium aluminum silicate) feldspars are the end members of a series called plagioclase. These two molecules form a complete solid solution series ranging from pure soda feldspar at one end to the pure lime feldspar at the other end. Intermediate solid solutions are known as oligoclase, andesine, labradorite, and bytoconite. The general structure throughout this series is the same. Sodium and calcium may replace each other and silicon and aluminum may replace each other in the structure.

Jan 10, 1958