Search Documents

By Fred R. Harris

INTRODUCTION MacMillan Tungsten is located in northwestern Canada on the border of Yukon and Northwest Territories at a latitude of 63º17' and altitude of 1800 m above sea level. The deposit lies within the Selwyn Mountains 10 km from the Canol Road. It is 660 km by road from Whitehorse, Yukon, and 1325 km by air from Vancouver, British Columbia. MacMil lan Tungsten is a contact metasomatic deposit in gently dipping Lower Paleozoic limestone and limestone breccia adjacent to a Cretaceous quartz monzonite stock. Four tabular tungsten skarn horizons contain total geological reserves of 30 million tons grading 0.9% WO3. DISCOVERY AND HISTORY J.F. Allan, a former AMAX geologist, located mineral claims in September, 1962, to cover the source of scheelite-bearing skarn float found in the headwaters of Cirque Lake Valley. Exploration work on the property conducted mainly between 1968 and 1973, includes geological mapping, 10,500 m of diamond drilling in 73 holes, and 735 m of underground exploration. Mil 1 tests were carried out on a 300 ton bulk sample obtained underground. Preliminary feasibility studies, collection of weather data and a variety of environment studies have been carried out since 1973. Although no production date has been set MacMillan Tungsten will undoubtedly be a major tungsten producer.

Jan 1, 1976

By Maurice B. Dusseault, Edo Nyland

Numerous consistent seismic signals are being generated in a pilot fireflood in a 750 m deep high permeability unconsolidated channel sand in Eastern Alberta. The pilot has a central air injection well, eight production wells on artificial lift, and two internally placed observation wells. Surface seismometers and a 12-hydrophone downhole string were deployed to detect seismics signals. Date were collected for 22 hours employing signal-triggered event detectors recording on cassette tapes. Monitoring during twelve hours of steady air injection at 625m3/s yielded a clear event frequency of about 50 events/h. The events were mostly clear compressional wave arrivals originating in the vicinity of the firefront. Stopping air injection caused a gradual drop in event frequency, and the rate was reestablished when air injection was reinitiated. Spectral frequency analysis and knowledge of material properties indicate that the events are shears of a stick-slip nature associated with the strain-weakening behavior of the over-compacted reservoir sands. The event amplitude indicates small-scale shearing, and different amplitudes suggest that planes re-shear with lower energy release levels. The triggering mechanism for shear rupture is high shear stress created by thermal expansion in the area of highest ther- mal gradient. Other enhanced recovery techniques may also produce useful signals for process control. In particular, steam flooding, hydraulic fracturing, and high-pressure injection operations likely generate mappable microseismic events which can be applied directly to production/ injection strategy.

Jan 1, 1982

By Arturo M. Morales

INTRODUCTION Manganese carbonates are nodulized by Cia. Mineral Autlan, located in Ongongo in the state of Hidalgo in Mexico. This kiln is fed minus 15 mm material at the rate of 1870 tpd. About 920 tpd is nodulized into a commercial product having a size range of 15 mm to 12 mm. The kiln also produces about 320 tpd of minus 12 mm fines and 40 tpd of chimney dust. Currently, the minus 12 mm fines are being recirculated to the kiln and the chimney dust is not being utilized. It has been found that there exists a market for manganese to be used as feed to the ferromanganese and silicomanganese furnaces. However, a coarse, lumpy feed can only be used in these furnaces. Accordingly, it has been proposed to screen the fines at 6 mm and agglomerate the minus 6 mm fraction along with the chimney dust and suitable binders. This paper presents the results of a feasibility study and test work aimed at producing an acceptable agglomerated product from the kiln fines for use in the ferromanganese and silicomanganese furnaces. Since the agglomerated product will have to be handled and loaded into trucks in the kiln area and transported over long distances, a minimum strength of 200 N is expected to be necessary. They should also have enough initial strength to be stockpiled and result in a minimum of breakage. A third important requirement is that the agglomerates should be resistant to disintegration during combustion. The recirculating fines were to be agglomerated in their original state, if possible, that is, without grinding. This eliminated the possibility of pelletizing as an agglomeration method. Based on a few laboratory trials, the briquetting method seemed most attractive, and a test program was initiated to explore the briquetting process.

Jan 1, 1977

By Guy A. Johnson

In 1976, The Bureau of Mines developed a prototype system to sense and extinguish fires in shafts and shaft stations in underground metal and nonmetal mines. Subsequent work modified this technology to include fueling areas, spontaneous combustion zones and coal mines. This paper updates IC-8783 "In-mine Fire Tests of Mine Shaft Fire and Smoke Protection Systems," which was published in 1978 and summarized the design and in-mine, actual fire testing of the first prototype mine shaft fire and smoke protection system. This paper also updates related work from IC-8775 "Spontaneous Oxidation and Combustion of Sulfide Ores in Underground Mines," (also published in 1978) and IC-8808 "In-mine Evaluation of Under- ground Fire and Smoke Detectors," (published in early 1979).

Jan 1, 1982

By D. S. Cahn, D. W. Fuerstenau

Specimens of glass, plexiglass, and naturally occurring minerals were irradiated by a 15-joule ruby laser pulse to determine criteria for the fracture of nonmetallic solids by internal thermal stresses. Fracture did not occur in those specimens with either a very high or very low internal absorptance or with a high spectral reflectance. If significant amounts of melting and vaporization do not occur at the surface of irradiation, the specimen will fracture if a derived 11fracture stress" exceeds the ultimate tensile strength of the specimen. The purpose of this investigation was to determine criteria for the fracture of nonmetallic solids by internal thermal stresses which are caused by absorption of laser irradiation. A laser produces a very short pulse of light which has a high energy density distributed over a very narrow part of the visible spectrum. The laser system used in this investigation had an energy output of 15 0 joules at a wavelength of 6940 A. Fracture in a non-metallic solid, then, would be caused by the absorption of light energy by that solid, and subsequent conversion of this energy to heat or mechanical energy. Fracture is caused by internal stresses that result from rapidly imposed nonequilibrium thermal gradients. ANALYSIS OF CONDITIONS FOR FRACTURE BY LASER IRRADIATION For this analysis, the laser beam is assumed to be circular and centered on the junction of the major and minor axes of a rectangular specimen. The laser beam forms a cylinder of radius rb extending through the specimen width. The beam cylinder may be then thought of as a heated mass constrained by a surrounding unheated mass. The instantaneously heated cylinder will at-

Jan 1, 1968

By Van Manning

IN SUBSTANCE, the international aspects of the petroleum industry, as these relate to the United States, are as follows: The domestic production is not keeping pace with the domestic demands; our best engineering talent warns us of the imminence of a decreased production by our oil wells, although more oil is needed; and the only practical source whence this increasing demand can be supplied for some time to come will be the foreign fields. Other nations have given thought to the future and, in recent years, have shown a tendency to adopt strong nationalistic policies regarding their petroleum resources, policies that hinder or prevent the exploitation of these resources by other nationals. In consequence, we find that, facing a probable shortage of the domestic supply, our nationals are excluded from foreign fields; and this in spite of the fact that foreign nationals have been permitted to enter into and exploit, our own oil resources on an equality with American citizens and without hindrance or restrictions. This country: has supplied the larger part of the petroleum consumed by the world and yet, with a failing supply imminent, it finds that those countries that have been drawing upon our resources to supply their needs are showing a tendency to exclude us from their resources. In this way we shall be transferred from a position of dominence to one of dependence; and only by sufferance of those countries that are now seeking financial or political control of petroleum supplies, shall we be able to obtain the oil we will need.

Jan 2, 1920

By H. B. Fuqua, B. E. Thompson

For a very brief description of the North Texas area and the general geological features with which it is associated, the reader is referred to the summary for 1935. As in previous years, the authors have been unable to undertakc the almost impossible task of isolating statistics for the hundreds of productive "spots" which are included within the generally productive areas of the several counties. However, pools that appear to be definitely isolated—as, for example, the Foard County production and the new pool recently developed southeast of Gainesville in Cooke County—are covered separately. During the year 1936, both routine development in proven or scmi-proven areas and exploratory drilling showed a decrease over the year 1935, there having been a total of 1453 wells drilled in the district during 1936, as compared to 1619 in 1935. It is also of interest to note that abandonments exceeded completions in 1936. Developments during 1936 While a number of local productive spots were found in Wilbarger, Archer and Wichita Counties, and numerous minor local extensions to older producing areas were developed in practically all the producing countics in the district, only two discoveries of sufficient importance to justify special mention were made. Anderson and Kerr No. 1 Bruhlmeyer, about two miles southeast of Gainesville in Cooke County, was completed in April, at a total depth of 2014 ft., for an initial production of 315 bbl. daily from a sand of Pennsylvanian (Canyon) age. Development has been rapid and the field is about drilled up. During November the 100 wells in the field averaged about 40 bbl daily. The structure appears to be a small fold associated with the northeast flank of the main uplift, which extends in a northwest-southeast direction across Cooke and Montague Counties.

Jan 1, 1937

By Willard H. Tracy

The method of seismic reflection prospecting has many times been compared to sound ranging, a process that became familiar to many during the World War. According to this very simple theory, the dynamite goes off and sends out a compression wave, which meets a reflecting horizon and returns to the surface, where it is recorded and the elapsed time of its travel in the earth accurately determined. Computations are then made on the general theory that the longer the elapsed time, the greater the depth of the reflecting bed. While this serves to give an idea of the fundamental basis of the process, it suggests a simplicity that does not exist in the life history of the various waves set up by a dynamite explosion in the earth. To begin with, a seismic wave in the earth does not obey the same simple laws of propagation that apply to a sound wave in the air. The property of strength in shear possessed by solids introduces a factor that sets such waves apart from the ordinary air waves. Also, the transmission charactcristics of the earth vary widely from place to place, and a fairly accurate knowledge of the space relationships of these variations is necessary if the final results are to be understood. Besides the waves recorded and used in the reflection computations, there are many

Jan 1, 1940

By J. Chipman, J. B. Gero, T. B. Winkler

IN the basic open hearth process the reaction of manganese in the bath with iron oxide in the slag attains a condition very closely approximating true equilibrium, and the distribution of manganese between slag and metal during the refining period is determined by the factors which control this equilibrium condition. For this reason a number of investigators have studied this reaction both in the laboratory and under various conditions of furnace operation. The principle reaction and its equilibrium constant are: FeO (in slag) + Mn = MnO (in slag) + Fe (liq.) [1] (MnO) .= (FeO),[%Mn] The symbols in parentheses represent activities of the two oxides in the slag which, in the simple slags consisting almost wholly of the two oxides, may be assumed equal to the respective mol fractions. The symbol (FeO)r is used to denote the total iron oxide computed as FeO; or it is the sum of the mol fraction of FeO plus twice that of Fe2O3. Early attempts to obtain laboratory data on this reaction suffered from failure to appreciate the great speed of the reaction. When slag and metal are cooled slowly together, the equilibrium shifts with temperature and the final compositions correspond to equilibrium at the freezing point rather than at bath temperature. The early work of Oberhoffer and Schenck¹ and of Tammann and Oelsen² apparently suffered from this source of error. In most of the other published laboratory investigationsa. '.' this error was not present but other uncertainties have existed, notably dependence upon optical temperature measurements and exposure to atmospheric oxidation.

Jan 1, 1951

By W. E. Thorne

The object of this graphic method is to estimate the weight of the casting, which is to be made from a given pattern, when the cross-section is not a uniform geometrical figure. Such an estimate is a very important guide to the foundryman, who would otherwise guess at the probable weight of a casting of new design, and, in trying to be on the safe side, would probably melt an unnecessary amount of iron. It is also an aid to the designer of a new car-wheel pattern, who must otherwise estimate from general experience the probable weight, have test-wheels made, and correct the pattern afterwards, so as to obtain the weight prescribed. For the method here described, an accurate drawing of the pattern is employed. This gives a closer result than a drawing of the wheel itself, for the following reasons: 1. Calculations based upon the actual dimensions of the wheel involve the erroneous assumption that the specific gravity of the casting is uniform throughout; and upon that basis the calculated weight would be wrong, because the amount of metal poured has shrunk in the mould, acquiring the highest density in the outside chilled portion, and growing less dense through the mottled to the gray portions. 2. Calculations based upon the dimensions of the pattern or " chiller " assume that the cooled metal will not have shrunk, but will have the volume of the pattern and a uniform density. These assumptions, though erroneous, counterbalance each other. For instance, the patterns and the chiller which give a wheel 33 in. in diameter when cold, are respectively 33.5 in. in diameter. This shows a shrinkage for wheel-iron of about & in. (ordinary gray pig is commonly assumed to shrink about 1/8 in.) per foot. Wheels cast in 33.5-in. chillers do not always have the

Jan 1, 1903

By Frank Fahrenwald

INTRODUCTORY A COMPLETE list of the elements as given for 1915 includes 18 that melt above 1,700° C. There does not exist one complete thermal equilibrium diagram for any pair of these 18 elements. Several of these elements have been combined, in relatively small proportions, with metals of lower melting point: e.g., tungsten, molybdenum, and vanadium, in steels, or with nickel and cobalt; but of this refractory group, platinum is the only one that has been extensively studied in this connection. When one considers that, with few exceptions, the industries have made use of alloys to the exclusion of pure .metals, it is reasonable to expect that alloys of this refractory group will invade fields in which the pure metals have found little application. The past neglect of this class of metals has, no doubt, been partly due to the rarity of some of them, for even though alloys of very valuable properties should be developed, their cost, unless in exceptional applications, would be prohibitive. There is also a well-founded reluctance to undertake research involving very high temperatures which, in the case of most of these elements, must be accompanied by an inert atmosphere as well. This combination of high temperatures* and control of atmosphere within the heating chamber of any furnace of present design is a difficult problem. It is the purpose of this paper to give results,1 of an investigation of one binary series of this group, in which methods were employed that avoided the usual difficulties accompanying high-temperature alloy investigation.

Jan 6, 1916

By Douglass D. Donald

The New Jersey Zinc Co. successfully holed through a 2 ½ -mile haulage tunnel connecting its new Ivanhoe shaft with the Van Mater Shaft at Austinville, Va. This 8 x 10-ft cross-section tunnel was driven from both ends and met at a point approximately a mile from one shaft and a mile and a half from the other. In order to make certain that the faces met accurately on line and grade it was necessary to refine conventional mine surveying practices. The mines that are serviced by these shafts are located in the southwestern part of Virginia approximately midway between Roanoke and Bristol at the west foot of the Blue Ridge. While the presence of lead-zinc sulfide ores has been known in this area for more than 200 years, it was in 1902 that New Jersey Zinc Co. acquired the Austinville property, which has been in constant operation since that time. About ten years ago the company undertook an extensive diamond drilling program at Ivanhoe several miles to the southwest. This program was successful in locating sufficient ore to justify the purchase of a number of the properties in this area and plans were made to develop the new orebodies. The discovery of this ore as well as substantial additional reserves at Austinville resulted in a decision by the company to increase its daily milling capacity to 3000 tons, of which about 1000 tons would be supplied from the Ivanhoe mine.

Jan 9, 1958

By Wallce E. Pratt

The Philippine Islands have produced no oil commercially; nevertheless, oil is known to be present at various places in the is1ands.l Although all attempts to produce oil commercially have failed, no intelligent, persistent exploration has been carried out. The Richmond Petroleum Corpn. (a subsidiary of the Standard Oil Co. of California) and a syndicate headed by Ralph Arnold are at present engaged in exploring Bondoc Peninsula in Tayabas Province, one of the promising Philippine areas, in a manner that promises to test the petroleum possibilities adequately and intelligently. How can the petroleum resources of an entirely undeveloped area like the Philippines be estimated, where not even the areal extent of the various geologic formations is known? Obviously no calculated figure for assured future production can be derived. Yet a study of the evidence of the occurrence of petroleum, the character of the possible reservoir beds, the probable source rocks, the character and size of favorable structures, and the area over which petroleum-bearing rocks are known to occur, will throw some light on the question. The fact that rocks of the same geologic age and similar composition have been explored and are producing in Borneo, Sumatra, and Java to the south and in Formosa and Japan to the north also affect the problem, so that one can obtain some idea of the quantity of petroleum that may reasonably be expected from the Philippines. It is this measure of the possibilities rather than a definite calculation of petroleum reserves that is presented herewith. This paper will not attempt to describe, nor even to enumerate in detail, the occurrences of petroleum in the Philippines, as such data have already been published. Fig. 1 indicates the localities where

Jan 1, 1923

By C. M. Ball

The magnetic concentration of iron-ores has been so often and so widely studied and discussed among the members of the Institute that any remarks concerning its general importance, from an economic standpoint, would be superfluous; but it is thought that a description of the Ball and Norton ore-separator, designed for cobbing and separating magnetic iron-ores, indicating its essential differences from other machines and the advantages claimed for it, together with some account of recent results obtained in its application to the concentration of such ores, will prove of interest. This machine is the joint invention of Mr. Sheldon Norton, of Hokendauqua, Pa., and the writer, and has been patented in the United States, Canada, and other countries. Of the accompanying illustrations, Pig. 1 represents a longitudinal vertical section of the perfected ore-separator, adapted for separating fine ore, and Fig. 2 the same, adapted for cobbing ore of the size of stove- or chestnut-coal. The two designs are identical in principle, and vary from each other in minor details only. The apparatus consists of a partially-closed chest, having an opening at f, from the feed-hopper, h, through which the ore is delivered to the machine from an ore-pocket or storage-bin provided with means for regulating the flow of ore, so that, when the machine

Jan 1, 1891

By H. E. Stauss, G. Sandoz

THE purpose of this note is to draw attention to the possibility that a melt may be contaminated by a material not in direct contact with it by means of gaseous intermediate agents. In recent years silicon has assumed a position of importance because of its use in rectifiers and transistors and close attention has been required to control of both purification and contamination during all stages of preparation.' This note reports the observation that a graphite heater may have contaminated silicon ingots without direct physical contact through reactions that developed gaseous products. Several ingots made with the equipment of Hino and Stauss,2 using a graphite heater in a dried helium atmosphere, were found to have a small amount of a very hard substance on the free surface. X-ray analysis by F. W. von Batchelder showed the sub- stance to be Sic. Similar contamination was not found when the heater was tantalum, indicating that the carbon had not come from an original impurity in the silicon powder. One source of the carbon could have been volatile matter released from the graphite heater. This heater had been used about ten times at the time of the observations. A second source of carbon could have been a direct reaction between the quartz crucible and the graphite heater to form CO, or an indirect reaction involving a crucible-melt interaction and volatile SiO as an intermediate product. Such reactions should have developed Sic on the heater; and in fact a yellow powder did form on the inside of the graphite heater although its composition could not be determined. References 'H. C. Torrey and C. A. Whitmer: Crystal Rectifiers (1948) Chapter 10. New York. McGraw-Hill Book Co. 2 J. Hino and H. E. Stauss: Trans. AIME (1952) 194, p. 656; Journal of Metals (June 1952).

Jan 1, 1954

By J. D. Lubahn, R. P. Carreker, J. G. Leschen

The formation of slip bands in crystalline solids undergoing plastic deformation has recently been treated as a problem of nu-cleation and growth.' A simplified theory was developed and shown to be qualitatively consistent with certain experimental observations reported in the literature, such as the frequent failure of slip bands to traverse the entire crystal, the effect of specimen diameter and temperature on the yield stress, and the occurrence of incubation periods in the deformation of suddenly loaded crystals. The theory further predicts the appearance of transients in the rate of strain of a crystal when the applied stress is suddenly changed from one constant value to another. A transient consists of a discontinuous change in the strain rate followed by a gradual approach to a steady-state value. Such transient behavior apparently has not been recognized in previous experimental work. The preliminary experiments reported in the present paper were undertaken to confirm the existence of the predicted transients and thus to determine whether a more detailed treatment of the nucleation theory of slip might be theoretically and experimentally fruitful. Experimental Procedure A simple creep apparatus was assembled as shown in Fig I. Very little insulation was used on the furnace in order to facilitate rapid changes of temperature. Temperature was measured with a thermometer placed in the center of the furnace and was controlled by adjusting the Variac setting. The specimens were cold-headed in split-cylinder grips. The strain was measured as total elongation by a dial gauge sensitive to I/I0,000-in movement of the weight pan. Since the specimen gauge lengths were

Jan 1, 1949

By W. G. Pfann

Formation and slow solidification of a molten zone in a homogeneous ingot produces a discontinuity in solute concentration at the boundary of the zone and a gradient of concentration within the zone. By using two solutes, one a donor, the other an acceptor, step or graded pn barriers can be produced. EXPLOITATION of the difference in concentration between a molten solution and the solid which freezes from it is continued in this paper. The normal segregation which results from this difference has been used for purification'.'2 and for pn barrier-formation in semiconductors."4 By means of traveling molten zones this difference has been used to effect multistage separations and to eliminate segregation in ingots." a It will be shown here that by means of stationary molten zones this difference can be used to produce discontinuities in concentration. In particular it will be shown that a pn or npn barrier can be made by the simple act of melting and refreezing a portion of a block of semiconductor, provided that the block contains proper concentrations of a donor and an acceptor in solid solution. Assumptions The operation of melting and slow refreezing will be called remelting and the interface between liquid and solid at the start of refreezing will be called the remelt bormdary. While remelting may be done for various shapes of starting crystal and remelt zone it will be assumed that the remelt zone is cylindrical, its length being measured in the direction of freezing, which is normal to the remelt boundary, and

Jan 1, 1955

Jan 1, 1933

By Howard L. Hartman

Probably no aspect of underground excavation is as important or as neglected as the environment. The Committee on Rapid Excavation, formed by the National Academy of Engineering to study the technological needs for "rapid" underground excavation in tunnels, shafts, and mines of the future, encountered a blank wall in attempting to evaluate environmental needs. In fact, so little quantitative information on the extent of present-day hazards is available that projection of future environmental-control demands must await more adequate assessment of current hazard levels. Further, there are not even accepted tolerance standards for many environmental conditions, such as heat, noise, and illumination. Only certain atmospheric contaminants have been satisfactorily catalogued. Any technical study, therefore, which purports to examine the state-of- the-art on underground environmental control must, in reality, settle for a cursory survey of a rather nebulous subject. ENVIRONMENTAL HAZARDS To contend adequately with hazards in the underground environment requires some knowledge of their nature and characteristics. In this regard, it is helpful first to identify our concern: when, where, and to whom or what may environmental conditions constitute "hazards"? Table 1 summarizes considerations that are important in this regard. For the purposes of this Conference (and book), primarily directed toward the excavation process itself, the hazards of consequence occur during excavation (item A) and primarily within the excavation (item B). However, some attention must be given to external hazards as well, since these may affect excavation. The object of concern (item C) is mainly human safety, although property security is also important. Hazards occur in a variety of forms. If one is to devise suitable control

Jan 1, 1970

By Rossiter W. Raymond

The most important event in the history of mining in the United States was the discovery of gold in California, which led to the rapid development, not only of a new industry, but of a new empire. The settlement of the Pacific slope was making but slow progress under the inducements of a scanty commerce in furs and hides. The liberal grants offered by the government to agricultural pioneers in Oregon had attracted to the Willamette valley and other favored points in that territory a limited population; hot the government of the Mexicans in California was positively unfavorable to enterprise. It is true that gold was known to exist in the country. Rumors of it were current among the trappers, and placers had actually been worked in what is now Los Angeles County; but the padres of the neighboring mission of San Fernando had discouraged the business as demoralizing to their flocks; and the existence of the precious metal was not widely known; still less was its distribution northward suspected. The discovery of gold, January 19th) 1848, at Sutter's saw-mill, on the south fork of the American River, afterward famous as Coloma, in Eldorado County, was the beginning of the new epoch. This discovery was made by James Wilson Marshall, a partner in the mill, who observed in the debris washed down by the tail-race a glittering fragment of a mineral unknown to him. Suspecting it to be gold, he sought for further specimens, and obtained, in the course of a few days, several ounces of it. Tests subsequently