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By Paul F. Kerr

QUARTZ of a certain kind, is one of our strategic minerals, and Brazil is probably the one important available source. Crystals of quartz of suitable size and perfection for piezoelectrical application are rare; their most outstanding use is in radio work. Clear quartz, or "crystal," free from twinning, cracks, foreign particles of other disturbing lines of growth, and gaseous or liquid inclusions, is cut into plates which provide excellent control of frequency in broadcasting. The squares or rectangles are less than a millimeter in thickness and ordinarily on the order of 1 in. along each side. They are cut at definite angles with respect to the axes of the crystal, and ground with opposite surfaces parallel. Each small slab must be a section of one crystal, uniform throughout in atomic alignment. The thickness of the chip controls the frequency of a broadcast and it is most important to have the plates oriented and ground with utmost precision. Opposite surfaces are parallel to within 0.001 mm. and expansion or contraction due to the temperature is limited to one part in a million.

Jan 1, 1942

By L. R. Raymond

With the trend toward deeper and consequently hotter holes, measurements of drilling mud properties at atmospheric temperatures are becoming increasingly inadequate.' Both the prediction and control of down-hole mud properties depend in part upon our knowledge of temperatures in the wellbore. Consequently, a better understanding of factors that affect temperatures during circulation and trips could improve drilling operations. It was toward the goal of obtaining this understanding that this study was directed. Other investigators2 have studied the response of fluid temperature in the borehole during trips. However, all of these studies have used an assumed formation temperature profile at the conclusion of circulation and have provided no means to calculate this profile directly. In this study, the formation profile during circulation was calculated. Other investiga-tors3-5 have also studied bottom-hole temperature during circulation. However, they have developed neither general techniques for calculating the entire temperature profile in the system nor generalized methods for predicting bottom-hole fluid temperatures during circulation. Such techniques and methods have been developed and are discussed briefly in the following pages. Temperature Behavior During Circulation Circulation of fluid during the drilling operation is represented schematically in Fig. 1. The process of circulation has three distinct phases: (1) fluid enters the drill pipe at the surface and passes down the drill pipe; (2) fluid exits the drill pipe through the bit and enters the annulus at the bottom; and (3) fluid passes up the annulus and exits the annulus at the surface. To simulate the thermal behavior of the fluid in the system, each of the phases of circulation must be described mathematically. In Phase 1, the fluid enters the drill pipe at a specified temperature, TDo. As the fluid passes down the pipe, its temperature is determined by the rate of heat convection down the drill pipe, the rate of heat exchange between the drill pipe and the annulus, and time. Phase 2 of the circulating process merely requires that the fluid temperature at the exit of the drill pipe be the same as the fluid temperature at the entrance of the annulus; i.e., TD(L,t) = TA(L,l). Thus in Phase 3, the fluid enters the annulus at TD(L, t). As the fluid flows up the annulus, its temperature is determined by the rate of heat convection up the annulus, the rate of heat exchange between the annulus and the drill pipe, the rate of heat exchange between the formation adjacent to the annulus and the fluid in the annulus, and time. These rates of heat exchange and the time dependency of mud temperature are described by well known heat-flow equation.6 Consequently, as shown in the Appendix, the temperature profiles in the drill pipe, annulus, and formation can be obtained by solving Eqs. 1 through

Jan 1, 1970

Data for 1962 world-wide, non-communist bloc geophysical activity, including geochemistry, are now available through the Society of Exploration Geophysicists. This information was made available to the AIME Geophysics Unit Committee through the courtesy of Charles L. Elliot, Mining Coordinator for the SEG. The data were compiled from 245 responses to 496 questionnaires mailed (49%). The data for the U.S. are a realistic representation of actual activity, followed by Asia, Canada, Europe, Australia, Africa and Latin America in order of decreasing reliability.

Jan 9, 1963

By S. C. Oliphant, C. R. Houssiere, George H. Fancher

DRILLING mud can be an item of great expense on the Gulf Coast. In order to understand the nature of a drilling mud, it is desirable to know the composition and size of the mineral particles that are present, The supercentrifuge has been adapted to the fractionation of mud, and this paper discusses the calibration and methods of operation and control. An alignment chart has been prepared, which was found useful in this work. Typical data are included, showing the comparative reliability of the method.

Jan 1, 1942

By Luke L. Y. Chang, Bert Phillips

A number of molybdenum oxides have been synthesized and their crystal structures have been described.' No data have been published on the stabilities of these oxides nor on the phase relations in the system Mo-0. It is probable that the tendency toward oxidation of both the metal and the oxides with low oxygen content in addition to the high volatilization rate of the oxides with high oxygen content have precluded accumulation of reliable data for establishing phase relations. These problems make experimentation difficult, but a modifi-

Jan 1, 1965

By G. H. Billings

The following data were collected some years since in the course of a series of experiments with oil as a substitute for coal in puddling, the earlier form of the Archer apparatus being employed. While I am not at liberty to give the name of the works at which the tests were made, I can personally warrant the accuracy of the record, and feel justified, therefore, in making this contribution to a discussion in which all trustworthy figures are likely to be helpful. Oil in Puddling. Starting with everything cold, we used 3518 pounds of oil to get the furnace in condition to charge a heat. After charging, we ran until we took out 13,340 pounds of puddled-blooms, using 8437 pounds, or 1333 gal1ons of oil. At 49 cents per gallon, the cost for oil per gross ton of blooms was $10.91; with coal at $4.871/2, and a consumption of 1.5 tons per ton of blooms (the usual quantity is ton for ton), the cost for coal is $7.31. The quantity of oil consumed in heating the furnace to the proper temperature and to make the bottom, is not included in the oil consumption stated. The quantity used was 3518 pounds of oil. Usually, the furnace need only be lighted, but in this case it had been repaired, and it was necessary to make a new .bottom. This required the quantity of oil necessary to make three heats of blooms, or 2109 pounds. Deducting this from the 3518 pounds leaves 1409 pounds of oil as the quantity consumed every week in lighting up.

Jan 1, 1889

By M. H. Shumate

Rope-type haulage has had many applications in the mining and allied industries. Records have indicated favorable results both from a standpoint of efficiency and investment. The Truax-Traer Coal Co. has used some variations of rope haulage at their mines and preparation plants. They have built a system which solves their particular problems, and have an investment which has indicated an annual savings in operating costs. Rope haulage, as applied to the mining industry, goes back many years for both underground and surface mining, or a combination of both. The Truax-Traer Coal Co. has used gravity retarding hoists as well as several variations of rope haulage, including electrical and combinations of both, but each was limited in its use and application by natural conditions and economies of the operation. Several systems of rope haulage equipment are offered by manufacturers today for handling railroad car movement on a limited or continuous basis. The portal and railroad loading facilities of Truax-Traer Coal Co.'s Burning Star Slope mine, located in Jackson County, Ill., were moved in 1960. The old location was abondoned, eliminating 3% miles of underground track haulage. The mine was converted to an all-belt system, and coal is loaded at a new raw coal plant and shipped by railroad cars to a central cleaning plant. The company wanted to operate the surface facilities as efficiently as possible, employing a minimum number of workers, using the latest type railroad car movers. The existing rope haulage facilities at several locations throughout the country were examined and considered for the Slope mine location. The application of each appeared favorable but lacked flexibility, and it was difficult to justify the capital investment. The company decided to investigate the possibility of building a system that would apply to their problem, and have an investment that could be amortized in a relatively short period. SPECIFICATIONS They employed the services of Allen and Garcia Co. of Chicago, Ill. Through combined efforts, a railroad car rope system was designed to specifications as shown in Fig. 1. The Falk Corp. of Milwaukee, Wis. built the hoist to the specifications as shown in Fig. 2. It has an all welded base and pedestals. The all welded drum is not grooved. A single helical gear was used in lieu of herring bone type. A Falk speed reducer, Unit 90Y3-A, is driven by a 25-hp 1800-rpm, 440-V ac type 'C' (high starting torque) drip-proof, Frame 324-U motor. The speed reducer shaft is equipped with a solenoid operated ac spring set shoe brake, operating on a 7-in. diam. brake wheel. The dolly car, shown in Fig. 3, was field constructed, using the trucks and frame of a railroad tank car. Truax-Traer did not alter the frame but added plates and anchors for hoist ropes and frames for 8.5 tons of concrete to be used as ballast on the car. The limit switch operating shoe was also installed and the car coupler latch mechanism overhauled. The hoist rope selected was 1% in. in diam., 6x37 improved plow steel extra flexible, right lay, regular lay, with independent wire rope core, and preformed. Wedge sockets were used to connect rope to the dolly car as shown in Fig. 4. The system employs two 30-in. and three 16-in. diam. sheaves. All are bronze bushed and equipped with grease fittings. Larger sheaves are used for directional change of hoist rope and the smaller ones as snub sheaves to correct fleet angle of rope as it approaches the hoist drum. The Trench lay cable, buried between the two tracks, is used for electrical distribution and controls between hoists and operator's cab. Foundations for the system required 187 cu yards of reinforced concrete using approximately 60 cu yd each at three locations. Four hoists are employed in the system, two for each track. A pair is interconnected electrically and when one operates, moving the cars, the tail hoist idles with brake released. The process is repeated for the reverse direction. A limit switch, mounted in the track near each end of the system, is tripped by the dolly car as it approaches the hoist. The limit switch controls movement in one direction only, protecting the dolly car and establishing positive con-

Jan 1, 1962

By T. Sterry Hunt

Jan 1, 1884

By P. Barnes

THE sums given in the accompanying table are those actually paid for material and labor up to about August, 1875; but, as some parts of the machinery were not wholly completed at the starting of the works in September, 1875, the statement cannot be taken as an absolutely correct note of the total cost. A complete description, with engravings of the building and machinery, was given in Engineering, April 26th, 1878, in a paper by Messrs. A. L. Holley and Lenox Smith, to which convenient reference may be made. A detailed list of the construction accounts has been given in a paper, by the present writer, in vol. vi, Transactions of the Institute. A summary is given in the table of the items in each class which enter into the total cost, and also a note of the proportion which each of these items forms of the whole. A concise view may thus be obtained of the facts embodied in the statement, as a whole, even though it cannot lay claim to completeness in showing the entire or final cost. An urgent suggestion has reached the writer from a distant country that such statements of cost to be really most serviceable should give the details in days of labor, in weight of iron, and in number of brick, and to this an assent is most cordially yielded. It is true, however, that the mere labor of copying and compiling these details to such a degree of minuteness, would be very great, and, in any event, the probable difference between the plans of an existing establishment and one projected, would be so wide as to render even so complete a statement of cost of little more real service than the approximate notes given herewith.

Jan 1, 1879

By H. D. Hoskold

I. Instrument-Parts and Implements. Cross-hairs ; Stadia-measurement; Fineness of Graduation ; Cylindrical Gradu ation ; Nonius; Vernier ; One Vernier or two ; Leveling-Screws ; Troughton & Simms' Shifting Tripod-Head ; Hoskold's Shifting Tripod-Head; Hoskold's Extensible Tripod ; Electric Lamp ; Plumb-lines; Chain. II. Instruments. Compass (Mine-compaes of 1518, Compass of 1541, and Agricolals of 1556, Voig tel's Setz-compass, Circumferentor, Stanley's Hedley Dial, Compass on Tele scope, Hanging Compass, Lack of Precision) ; Plane-table; Octant and Quadrant; Theodolite and Transit (Evolution of the Theodolite, Scott's Tachymeter, Hoskold's Engineer's Theodolite, Angleometer, Precision of Mine-Theodolites). I. Instrument-Parts and Implements. Cross-Hairs.—Mr. Scott‡ says Lean's dial " might also have been provided with a diaphragm and cross-hairs; for Huygene discovered that any object placed in the common focus of the two lenses of a Kepler telescope (1611)- appeared as distinct and well defined as any distant body. Following this established theory, in 1669 Jean Picard, Marquis Malvasia and others crossed silken fibers in the mutual focus of their astronomical instruments." If by this Mr. Scott means that Huygens and Picard first devised and applied cross-hairs to the focus of the telescope, the writer cannot agree with him. Huygens did not describe " his telescope without tubes until 1684, in his Astroscopia Compendiaria."§ Moreover, it is recorded that the English astronomer, Gascoigne,?

Jan 1, 1902

By Emery R. Hayhurst

SILICOSIS has been described in a report of the American Public Health Association as a disease due to breathing air containing silica, characterized anatomically by generalized fibrotic changes and the development of miliary nodulations in both lungs, and clinically by shortness of breath, decreased chest expansion, lessened capacity for work, absence of fever, increased susceptibility to tuberculosis (some or all of which symptoms may be present), and by characteristic X-ray findings. ... The disease is divided arbitrarily into first, second, and third stages for convenience of description and possible compensation purposes. At least two distinct types of silicosis are recognized, acute and chronic. The acute form was reported as early as 1713, when a British patent for grinding flint by wet methods was granted because the dry powdered material "proved very destructive to mankind, so much that any person, ever so healthful, working in that business cannot possibly survive over two years."

Jan 1, 1936

By Charles E. Locke

CONTINUED expansion of gold mining in 1935 led to further developments in treatment methods. In base metals and non-metallics progress is also noted, coincident with greater activity. Statistics are not available yet for 1935 but the trend is shown by 1934 when nonferrous ore mined in the United States was 35,840,737 tons, or 45 per cent more than in 1933. The amount concentrated was 27,167,530 tons or 75.80 per cent of the ore mined, and flotation was used in whole or part on over 96 per cent of the ore subjected to concentration. In the crushing field a new model of the Fahrenwald crusher is promised soon. The Symons fine-reduction cone crusher and Traylor secondary crusher continue to gain as intermediate crushers. A new book entitled "Crushers for Stone and Ore" by William T. W. Miller appeared. The Hadsel mill has been improved still further and a number of installations are in satisfactory operation showing economical power consumption and low wear. An attempt in a

Jan 1, 1936

A mine in the mountains of southeastern British Columbia is fast earning a reputation as the safest metal mining operation of all time. Already officially proclaimed as the safest mine in Canada, the H.B. mine of The Consolidated Mining and Smelting Co. of Canada (Cominco) continues to advance its safety performance far in the lead of average accident frequencies in mines across the country. Official recognition came its way again this spring when the Cominco mine was awarded the John T. Ryan trophy for the fourth time in the last five years. This award is emblematic of top national safety performance of a metal mining operation. The H.B. mine is its only four-time winner. The Ryan award is based on a frequency of accidents involving lost time of more than six days. In each of the years that the H.B. has won the award-1958, 1959, 1961 and 1962-its frequency was zero, with no accidents involving a time loss of more. than six days

Jan 12, 1963

By P. A. Boeck

(San Francisco Meeting, September, 1915) THE thermal insulation of high-temperature equipment for industrial purposes is a subject that has not received from engineers and designers the attention its importance deserves. This may be attributed to a number of causes: In the first place, heat flow is a rather difficult factor to measure under the working conditions of an industrial furnace, and until the comparatively recent introduction into certain operations of the heat balance sheet, with a systematic attempt to account for the discrepancies in the totals, the various causes of heat losses and the reasons for their existence were not brought to light. Moreover, such rapid advancement and radical changes in the design of equipment, especially in metallurgical lines, have occurred that practice has apparently outdistanced the theory of design. In the modern tendency toward greatly increased size of units, effort has seemingly been made to utilize the heat of fuel gases without proper. attention having been paid to conserving heat energy and confining it strictly to the points of maximum activity. The systematic study of the thermal properties of structural materials, which is being carried out by various government bureaus and also by a number of technical societies, is forming the basis for more intelligent and consistent work in the economically important subject of prevention of fuel waste.

Jan 8, 1915

By R. J. Brison, W. C. Bleimeister

The International Salt Company has long been interested in finding an efficient process for the removal of impurities from rock salt, and particularly from the rock salt produced at the Detroit mine. Methods which have been used previously at the Detroit mine included both hand sorting and differential crushing in a Bradford breaker with rejection of the oversize. Neither of these methods was adequately effective. The development of a new process for removal of impurities from rock salt has been described in the preceding article." Basically, the process consists of exposure of crude rock salt to radiant heating which selectively heats the impure particles. Subsequently the heated particles are removed by adhesion to a heat sensitive-coating on a conveyor belt. This method was found to be effective in improving both the quality and appearance of rock salt by the rejection of the dark, impure particles. The first commercial unit employing the new thermoadhesive method of dry separation of minerals was installed at the Detroit mine of International Salt Company in Detroit, Mich. (Fig. l). This unit was first put into operation in March 1957. The purpose of the Detroit installation was 1) to serve as a pilot plant for evaluating the process on a commercial scale and 2) to produce marketable quantities of rock salt of improved quality and ap- pearance. The design of this plant was based on the results and information obtained from a 1-tph pilot plant at Battelle Memorial Institute. DESCRIPTION OF PLANT Location: The separation plant was installed underground near the crushing and screening plant, for this was the most suitable location from the standpoint of material handling. Furthermore, ample space was availabe at this location. Because the process requires a relatively constant temperature, the uniform year-around temperature of the mine (57°F) gave an added advantage to an underground operation. Feeding: The rock salt is conveyed to a surge bin, from which it is fed to the heating unit by a conveyor. The feed-rate control consists simply of an adjustable gate at the bottom of the surge bin. The plant may be fed either No. 1 grade of rock salt (0.279 to 0.375 in.) or No. 2 grade (0.375 to 0.500 in.) with a maximum input capacity of 500 tons per 15-hour day. Heating Unit: The heating unit (Fig. 2) consists of a panel of infrared lamps suspended inside a low-speed revolving screen. The radiant-heat panel, which is curved for most effective utilization of the heat, holds 240 infrared lamps of standard industrial type, each rated at 500 watts. The position of the panel is adjustable so that it can be placed centrally over and to within 6 in. of the salt bed on the screen. The entire heat panel is suspended by rollers in ¦ R. J. Brison and O. F. Tangel: Development of a Thermo-adhesive Method for Dry Separation of Minerals.

Jan 1, 1961

By AIME AIME

ATER the preliminary registration at which approximately 380 members and guests were registered, the 138th meeting of the Institute was opened in the Concert Room of the Palace Hotel. E. A. Hersam, chairman of the San Francisco Section, voiced a brief welcome and introduced F. W. Bradley, president of the Institute, who presided over the remainder of the morning session. After expressing the welcome of the Institute to the members and guests, he read a telegram from Secretary H. Foster Bain, extending the best wishes of the eastern staff and members for a successful meeting. He next introduced Theodore J. Hoover, dean of the School of Engineering, Stanford University, who read an address by the Secretary of the Interior, Ray Lyman Wilbur, briefly outlining California's part in the mining industry and giving the welcome of California to this meeting of the Institute.

Jan 1, 1929

By R. L. Tobie, E. K. Staley

Because of high production demands at San Manuel mine (approximately 40,000 tpd) and the relatively narrow grade range of the orebody, no attempt is made by the company to mine selectively. The caving sequence is laid out to meet the production demands, and proceeds in a manner to induce the least amount of weight on extraction openings. Once an area is undercut, draw control procedures are applied uniformly until the area has been mined to depletion. The orebody, located 50 miles northeast of Tucsoil, Ariz., is a low-grade deposit of chalcopyrite disseminated throughout a structurally weak, highly fractured, strongly altered granitic host rock over- lain by several hundred feet of relatively competent andesitic conglomerate. When undercut, the granite ore caves readily into fragments which usually pass through the grizzly without either excessive breaking or an undue amount of secondary blasting.

Jan 6, 1967

By Raphael D. Schilz, Michael F. Dunn, Edward D. Thimons, Francis S. Kendorski

During a mine fire or other emergency, it may be desirable to reverse the air flow in order to provide an escapeway or to control a fire. Also, in colder areas, the air flow may be reversed to prevent ice build-ups. When reversing main mine fans, the operator usually does not know what operating characteristics of flow and pressure to expect. Laboratory testing of vane axial main mine fans has been completed in order to establish forward and reverse performance characteristics under controlled conditions, with the results presented here. Preliminary tests under field conditions have also been conducted. The data obtained suggest that reverse performance characteristics are dependent upon the blade angle and the hub to tip ratio. There is also evidence that reverse performance can he predicted for a family of blade angles in a given hub to tip ratio. In general, the air quantity delivered by the fan is 30% to 60% less in reverse than when operating in the normal forward mode.

Jan 1, 1982

By FREDERICK J. ALCOCK

THE high prices which lead and zinc have commanded during recent months have given a great impetus to search for workable deposits of these metals, and there has accordingly risen a demand for information about deposits which have been worked in the past and which might possibly be opened up anew under these more favorable conditions. Production of zinc and lead in Canada has been on the increase during the last few years. In 1924, 175,- 485,499 lb. of lead with a computed value of $14,221,- 345 were mined. Of this, 96 per cent. was produced in British Columbia, 3 per cent. in Ontario, while Quebec and the Mayo district of the Yukon accounted for the remaining one per cent. During the same year the production of zinc amounted to 98,909,077 lb.. valued at $6,274,791. Of this 96,000,069 lb. were produced in British Columbia and the remaining 2,909,008 in Quebec. The large producer of zinc and also of lead is the Sullivan Mine at Kimberley, B. C. In comparison with the Sullivan, the deposits which are known to occur in eastern Canada are relatively small. Two, however, the Kingdoll lead mine at Galetta, Ontario, and the Tetreault zinc property at Notre Dame des Anges, Quebec, are steady producers. The object of this paper is to describe briefly these and other deposits of eastern Canada, to show their relation to geological events and to point out what are the chances of any of those which are idle at present developing into active producers or what are the possibilities of new deposits being discovered.

Jan 1, 1926

By W. R. Hamilton

The knowledge of the existence of petroleum in Southern California dates back to the days of the missions. The presence of asphaltum and semisolid bitumen was reported at Santa Barbara in 1792, but no serious attempt was made to develop oil until Professor Silliman's optimistic report in 1865 started California's first oil boom. Wells were drilled in many counties of the State, but the equipment was unsuitable and the drilling difficult and no production was obtained except in Ventura County. Even there the production was of little importance commercially, and not until the early '80s did it become sufficient to again attract attention. In 1888 the production for the State had reached a total of about 700,000 bbl. per year, practically all light oil produced in Ventura County, Pico Canyon, Los Angeles County and in the Puente Hills. The production of petroleum attained the dignity of an industry in 1895 when the Los Angeles City and Coalinga fields were discovered. The subsequent development has been remarkable, and in 20 years the production has increased from 1,000,000 to 100,000,000 bb1. per year. The refining industry has kept pace with the production of oil. The Pacific Coast Oil Co., the predecessor of the Standard Oil Co. of California, was the virtual pioneer refining company of the State, having built a refinery at Alameda about 1880. When purchased by the Standard, about 1902, it was dismantled and the refinery at Point Richmond was built. The Richmond refinery is now one of the largest in the world, having a capacity in excess of 60,000 bbl. per day. A small refinery was built by the Union Oil Co. at Santa Paula in the early days of the industry and later many asphalt refineries were in operation in Southern California. The Pacific Coast Oil Co. was then, as has been its successor, the Standard Oil Co. of California, the principal refiner and marketer of light products, the most valuable of which was kerosene. Before the opening of the twentieth century, gasoline of excellent quality was produced, though it was always a drug on the market and was produced for the simple reason that its presence rendered the flash and fire tests of the kerosene too low. The user of kerosene at the present

Jan 1, 1917