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By Ernest G. Enck

"The Rockets' Red Glare" of the Fourth of July is produced by strontium compounds. However, strontium has a number of less spectacular uses; i.e. in, or in connection with, the manufacture of ceramics, caustic soda, glass, railway and truck signal flares, beet sugar and steel. The principal ore of strontium for use both as the mineral and for production of compounds is celestite (SrSO4). This mineral varies in color from white to pink or blue depending on presence of impurities. It has a hardness of about 3.5 and specific gravity of 3.9. It is brittle and has perfect basal and prismatic cleavages. The high grade ore is obtained from England, hence it has become the standard for all other producing areas. (See analyses, Table 1.) The most objectionable impurity in English celestite is iron, coming mostly from adhering clay. On the other hand, Mexican celestite, while no higher in strontium sulfate content, is extremely low in iron (less than 0.2 pct), hence it is more desirable for certain uses. Most of the celestite in Spain and in the United States is high in calcium and barium, and commonly high in iron, and requires some form of beneficiation in order to be equal to English ore. The natural carbonate (SrCO3), or strontianite, is less important than celestite as a source of strontium, because it is less abundant and is not so widespread in its occurrence. Furthermore, it generally occurs with calcite (CaCO3) and lead sulfide (PbS), and for most uses these impurities are detrimental. This mineral is generally white or yellowish, forming needle-like crystals. It has a hardness of about 3.7 and a specific gravity of 3.68-3.8. The mineral is brittle and has an imperfect cleavage. A typical analysis of German strontianite is shown in Table 1. [ ] Distribution of Deposits UNITED STATES Occurrences of strontium minerals are known in Arkansas, Arizona, California, Illinois, Ohio, Pennsylvania, Tennessee, Texas, and Washington. Celestite occurs in the Vulture Mountains, Maricopa County, Arizona in beds three to ten feet thick associated with sandstone, gypsum, and barite. Because of the low strontium content, approximately 86 pct SrSO4, it has no commercial value. A large deposit of celestite occurs in San Bernardino County, California, in the Cady Mountains near Argus Station, about eight miles west of Ludlow. The celestite here is interbedded with shaly and clayey tuff in a zone about 300 ft thick. Massive, finely crystalline ore has been recovered with an analysis

Jan 1, 1960

By R. L. Sandefur

Professor Kim's excellent review article1 on ultimate pit planning contains a statement of the apparently widely held but incorrect belief that "kriging provides information on the confidence limits around the estimate which no other extension technique is capable of supplying." If a geostatistical approach is valid, there are several good reasons for using kriging but uniquely provided confidence limits is not among them. If kriging is possible, then confidence limits can be calculated for any other linear estimate. Kriging is the procedure which finds the weighing coefficients which minimize the estimation variance [ ] is the variance of blocks like the one being estimated. wi is the covariance of the estimated block and the i-th sample. oij is the covariance of the i-th sample and the j-th sample. Ai is the weighing coefficient for the i-th sample. N is the number of samples. The formula for estimation variance can also be used to calculate confidence limits on blocks estimated by any linear combination of sample grades including: 1) Polygons a. Hole nearest block centroid is assigned weight 1. All other holes are assigned weight 0. b. Polygonal area weighing. The samples are assigned weights directly proportional to their polygonal areas of influence within the block. The weights sum to 1. 2) Inverse distance weighing. The samples are assigned weights directly proportional to the reciprocal of their distance to some power from the block centriod. The weights sum to 1. Often only holes nearer than a certain distance and/or the nearest hole in each octant is considered. If there is an antisotropy to the ore body, an elliptical transformation often gives more accurate results. The most popular inverse distance weighing function is inverse squared distances (IDS). 3) Simple average. All samples within a certain distance are assigned the same weights which sum to 1. As an example of the applicability of the above formula to any linear estimate an internal verification on copper grade of 665 blast holes on the 1040 bench at Utah's Island Copper mine is presented. Internal verification is simple and applicable to non-linear estimates as well. Any sample (drill hole, bulk, trench, or chip) is dropped out, the value of the dropped sample estimated and compared with the actual value. If this is done for all samples, a measure of confidence limits is obtained. Internal verification is used in Cominco's MEPS system4 and in the BLUEPACK system.5 Comparison of block values against estimates697 is not dissimilar to internal verification. Results of the internal verification are presented below:

Jan 1, 1980

By W. L. Phillips

Stress-strain data are reported for sodium chloride, lithium fluoride, and magnesium oxide tested in compression at diffevent strain rates in the telrlperature range from 70° to 873°K. Quantitative equations are given for the stvain-rate dependence of the critical resolved shear stress and the initial rate of work havdening. The properties so determined are compared with results previously reported for metals. ALTHOUGH the effects of strain rate and temperature on the stress-strain characteristics of metals have been extensively investigated1,2 these effects have not been studied in detail in ionic crystals. In the only previous investigations on the effect of strain rate on the deformation of ionic crystals. Gilman and gohnston3 and Hulse and pask4 have shown that the yield stress of lithium fluoride and magnesium oxide at room temperature is proportional to the ninth or tenth root of the strain rate. CRYSTAL PREPARATION Lithium fluoride, sodium chloride. and magnesium oxide single crystals were purchased from the Har-shaw Chemical Co. The compression fixture and sample preparation have been described in detail previously.5 The detectable impurities in MgO were eight parts in 105 of Fe and six parts in 105 of Si; in LiF, six parts in 105 of Mg; and in NaC1, two parts in 105 of Fe and four parts in 10&apos; of Mg. The cleaved samples measured - 0.1 in. by 0.1 in. by 0.3 in. Prior to testing all samples were annealed at -0.8 of their melting point and cooled to room tempera- ture at 50 C per hr.&apos; Samples were strained at rates (<) of 0.1, 0.01, 0.002, and 0.0002 in. per in. per min. EXPERIMENTAL RESULTS Fig. 1 is a plot of the critical resolved shear stress a,. (extrapolation of slope of easy glide region to zero strain) of sodium chloride, lithium fluoride, and magnesium oxide tested at different strain rates as a function of temperature. In all crystals at all strain rates a, decreases with increasing temperature according to an equation of the type397 where uo is a stress constant, K is a constant, and T is the absolute temperature. The points in Fig. 1 are the average of six tests. It is evident that there is a break in the log 0,- temperature plots at a characteristic temperature T,. The constant K of Eq. [I] is dependent on strain rate, Fig. 2. The relationship

Jan 1, 1962

By R. H. Swallow, George Hess

C. G. BALL*—These maps are obvi-~,usly quite helpful in many types of mining engineering, but I want to find out if the prints which you obtain in the first step toward making any aerial contour map have already been corrected for tilt. Is that done afterwards only if you are going into the process of making a contour map ? GEORGE HESS (authors&apos; reply)— The tilt correction is the first step in either compiling the mosaic or compiling the total map. They must be corrected. C. G. BALL—But are the contact prints themselves corrected for tilt? GEORGE HESS—They are not corrected. E. R. KAISER†—I enjoyed this paper very much, and am glad to learn that the methods have a high degree of accuracy and are in use in the coal industry. Accuracy in dimensions is understandable from the paper. Would you tell us how accuracy can be obtained in the vertical dimensions by means of the photographs so as to permit drawing contour lines? GEORGE HESS—To explain our process, even in a limited way, is quite a large order. However, the basic principle involved is the measurement of parallax by viewing two overlapping photographs stereoscopically. It would almost be necessary to have the various instruments here on view to adequately explain their operation. E. R. KAISER—Are the elevations for reference obtained at more than four points ? GEORGE HESS—The pattern of control is four points obtained in the corners. Primarily. that is to restitute the picture and horizontalize it. The vertical control points are read ill on the stereometer and a direct comparison is made while draw- ing the contour lines. You do have to have those four points. But one stereoscopic pair of 5 ft contours has some 340 acres on it, consequently for every four points picked up 340 acres are contoured. E. R. KAISER—How does your method compare with that used by the military reconnaissance during World War II? GEORGE HESS—The Army did not get into this refined mapping. Most of their work has been reconnaissance mapping by taking one vertical and two oblique views. Basically, the same principle is used. Our maps are for engineering purposes. The Army was primarily interested in reconnaissance. E. R. KAISER—You could take more than 48 pictures in one flight? GEORGE HESS—Yes, the Brock camera accomodates 48 pictures per magazine. We are limited by the hours of greatest light, though, 2 hr before high noon, and 2 hr after high noon. Shadows do affect the picture. The shadows can-

Jan 1, 1950

HenRy Clay FRick, a pioneer in modern coke and steel industry and, in more recent years, one of the outstanding financiers of America, died on Dec. 2, 1919, at his home on Fifth Avenue, New York. Although he had been ill since election day, when he had an attack of indigestion which developed into ptomaine poisoning, his death was a surprise to all. He is survived by his widow, Adelaide Howard Childs Frick; a son, Childs Frick, one unmarried daughter, Helen C. Frick, and four grandchildren. A quiet funeral service was conducted at the Frick home on Wednesday afternoon by the Rev. Dr. Leighton Parks, pastor of St. Bartholomew&apos;s Episcopal Church. This was attended by members and very intimate friends of the family, Trustees of the Metropolitan Museum of Art, Officers of the Links Club, and Directors of the United States Steel Corpn. Henry Clay Frick was born Dec. 19, 1849, in West Overland, Westmoreland Co., Pa. His father, John W. Frick, was a farmer of Swiss ancestG, and his mother, Elizabeth Overholt Frick, a member of an old Mennonite family. Until he was sixteen, he spent his time at school, on his father&apos;s farm, and in his grandfather&apos;s distillery, where he kept books. He attended Otterbein University, in Ohio, for a year. Frick, learning that coke was an essential of the already rapidly developing steel business, early invested every cent he could get in coking-coal lands. With the help of an associate of his grandfather, he formed the corporation of Frick & Co., coke dealers, and acquired fifty-one ovens in the Connellsville region and 300 acres of soft-coal lands. During the panic of &apos;73, with the help of Judge Thomas Mellon, a Pittsburgh &apos;banker, he bought out his partners and while coke was selling at 90 cents a ton enlarged his purchases of suitable lands. Later, the price of coke increased until it was selling at $5 a ton. Before he was 30 years old, Frick was rated a millionaire. Association with CaRnegie In 1878, he sold an interest in the business Do E. M. Ferguson of New York, and later a share to Mr. Ferguson&apos;s brother. Four years later the business was reorganized into the H. C. Frick Coke Co. with vast coal lands, great banks of ovens, and a capitalization of $2,000,000. Then began his association with Andrew Carnegie. He exchanged a part of his coke interest for shares in Carnegie Brothers of Pittsburgh,

Jan 1, 1920

By T. E. Ockershauser

The Southwest Antioch Oil Field located in T2&3N - R2&3W, Garvin County, Okla., was discovered in February, 1946, by The Globe Oil & Refining Co. and The Vickers Petroleum Co. at their Melinda Gibson No. 1. Oil production was encountered at a depth of 6,525 ft in 14 ft of lower Pennsyl-vanian sandstone. The producing sand, locally called the ."Gibson" or "Third Deese," is a sand bar deposit strung along the west flank of the Pauls Valley uplift in a northwest-southeast direction. The oil reservoir is defined to the east by the edge of sand deposition along the uplift and to the west by the gradation of sand into shale. Within the Antioch Unit, the sand dips from 150 to 400 ft per mile southwesterly and has a pay thickness varying from 10 to 55 ft and averaging 28 ft. Several areas of Gibson production have been developed, including the Katie pool on the south, the Elmore Area of the Southwest Antioch Gibson Sand pool. the Southwest Antioch Gibson Sand pool proper, the Southwest Maysville pool and the New Hope pool on the north. Production extends over a belt 22 miles long by about two miles wide and is continuous except into the Katie and New Hope pools. It appears that drilling will soon prove these intervening areas productive. To March 1, 1950, approximately 18,000 acres have been developed with 450 Gibson wells. It is likely this count will ultimately reach 32.000 acres with 800 wells. RESERVOIR The natural production of oil from the Gibson reservoir is primarily due to solution gas expansion though gravity also plays a part. There is no indication of water drive or evidence that an initial gas cap existed. Gibson oil has a stock tank gravity of 43" API and was saturated at the original reservoir pressure of 2.925 psi. It contained 1,3440 cu ft of gas per bbl in solution and had a high shrinkage of 70 per cent. Connate water amounts to 15 per cent. Reservoir temperature is 130°F. Porosity averages 15.5 per cent and permeability ranges from less than one md to over 1.000. Based on meacurement of 400 core plugs from 15 wells, 78 per cent of the permeabilities fell within the 10 to 1,000 md bracket and averaged l67. Primary oil recovery is estimated at 140 bbl per acre-ft or 22 million bbl for the present 137-tract unit. Due to unitization

Jan 1, 1951

By D. Van Winkle, C. Zener, H. Nielsen

THe internal friction of metals has been studied frequently at elevated temperatures.1-4 In most cases it rises rapidly with increasing temperature. The notable exceptions are ferromagnetic materials, and lead.2 This paper describes an investigation of the general features of the high-temperature internal friction of 70-30 alpha brass. Experimental Method The internal friction of a metal is a measure of the rate at which it dissipates energy of vibration. The measure adopted here, I/Q, is (I/2p) times the specific damping capacity, a measure commonly used by engineers. In the measurements of this investigation, the stress level was kept so low that the observations were independent of the stress, The general method of making such measurements, and of observing temperature of a specimen during a measurement, has been described.5.6 The driver and detector coils were wound with wire insulated with glass thread, in order to withstand the high temperatures used. In previous work electrical eddy currents in the specimen served as the coupling between the mechanical vibration of the specimen and the electrical circuits of the driver and detector. The high values of the internal friction in the present investigation rendered this coupling insufficient. In order to increase this coupling, pole pieces cut from ordinary telephone diaphragms were attached to the specimen. A mixture of French chalk and water glass proved a satisfactory cement. All measurements were made at the fundamental frequency for transverse vibration, which lay between 600 and goo cycles per second. Specimens The measurements described herein were made upon a single cylindrical rod of brass, kindly furnished by Dr. Cyril Stanley Smith, of the American Brass Co. This rod was the specimen E of the set of alpha-brass rods described in an earlier paper.6 Successively larger grain sizes were obtained by annealing at .successively higher temperatures. A slice was cut off one end after each set of measurements. Grain counts were made on each slice by W. E. Lindlief, of the American Brass Co. Nine fields were viewed on each piece, located as shown in Fig. I. Results are given in Table I. The grain size is defined in the usual way; namely, Grain size = I/n1/2 where n is the mean number of grains per square millimeter. Experimental Results This paper is concerned exclusively with the part of the internal friction that be. comes dominant at high temperatures. It is thus desirable to separate this part of the internal friction from the part that is

Jan 1, 1942

By C. Zener, H. Nielsen, D. Van Winkle

THe internal friction of metals has been studied frequently at elevated temperatures.1-4 In most cases it rises rapidly with increasing temperature. The notable exceptions are ferromagnetic materials, and lead.2 This paper describes an investigation of the general features of the high-temperature internal friction of 70-30 alpha brass. Experimental Method The internal friction of a metal is a measure of the rate at which it dissipates energy of vibration. The measure adopted here, I/Q, is (I/2p) times the specific damping capacity, a measure commonly used by engineers. In the measurements of this investigation, the stress level was kept so low that the observations were independent of the stress, The general method of making such measurements, and of observing temperature of a specimen during a measurement, has been described.5.6 The driver and detector coils were wound with wire insulated with glass thread, in order to withstand the high temperatures used. In previous work electrical eddy currents in the specimen served as the coupling between the mechanical vibration of the specimen and the electrical circuits of the driver and detector. The high values of the internal friction in the present investigation rendered this coupling insufficient. In order to increase this coupling, pole pieces cut from ordinary telephone diaphragms were attached to the specimen. A mixture of French chalk and water glass proved a satisfactory cement. All measurements were made at the fundamental frequency for transverse vibration, which lay between 600 and goo cycles per second. Specimens The measurements described herein were made upon a single cylindrical rod of brass, kindly furnished by Dr. Cyril Stanley Smith, of the American Brass Co. This rod was the specimen E of the set of alpha-brass rods described in an earlier paper.6 Successively larger grain sizes were obtained by annealing at .successively higher temperatures. A slice was cut off one end after each set of measurements. Grain counts were made on each slice by W. E. Lindlief, of the American Brass Co. Nine fields were viewed on each piece, located as shown in Fig. I. Results are given in Table I. The grain size is defined in the usual way; namely, Grain size = I/n1/2 where n is the mean number of grains per square millimeter. Experimental Results This paper is concerned exclusively with the part of the internal friction that be. comes dominant at high temperatures. It is thus desirable to separate this part of the internal friction from the part that is

Jan 1, 1942

Book Review MAN-TO-MAN: THE STORY OF INDUSTRIAL DEMOCRACY. By John Leitch, Phila¬delphia, Pa. The B. C. Forbes Publishing Co., New York, 1919, 2.19 pp., 7 1/2 X 5 in. $2.00. "Man to Man" is a short, well-written, well-printed, easy to read and very interesting hook. It is an account of a method introduced into more than twenty industrial plants to give the workers a share in managing their own troubles. It is not a panacea for labor troubles and strikes, but neither have existed where the new method has been tried. The scheme is, in a word, to organize the working force like the government, having a cabinet composed of the executives, a senate composed of foremen, and a house composed of men elected by fellow workers from all departments. This governing machinery takes up all complaints of workers, investigates, reports, and settles. The increased profits due to economy and increased production from this cooperation are divided 50-50 between the company and the men. Experience has shown that, since inattention, tardiness, irregularity, and inefficiency tend to reduce their profits, all men very quickly, after once convinced of the sincerity of the management in their scheme of cooperation, eliminate them because it is for their personal profit. Astonishing results have been attained, including higher wages, greater output, lower unit costs, great reduction in labor turnover, elimination of waste, an increased loyalty and a waiting list of employees even in periods of labor shortage. Profit sharing as such and stock ownership as a benefit to industrial relations are discussed briefly and illuminatingly, although they are not believed by the author to he the best way to bring about the human relation between those who work,for and those who work with money. The author is not against unions but does not believe the union is the best medium for improving industrial relationship. The look is nowhere dogmatic but is always forceful and convincing and, being well written, is very entertaining. It is doubtful if "Industrial Democracy" is the right expression for the solution of the problem but certainly anything that will place on the shoulders of labor some of the responsibility of industry and will increase production is tine much-to-be-desired desideratum. It is a. contribution to the solution of our biggest problem and should be read by everyone who employs men and who has been worried by the labor turnover. P. E. B.

Jan 7, 1919

As described in the section on the Palabora twin crushers, the Palabora ore consists of two types: a carbonatite containing a low titanium magnetite, and a foskorite containing high titanium magnetite. As the Palabora pit was widened and deepened, more and more of the foskorite had to be mined. The 25,000 mt expansion of the Palabora plant which went into operation in early 1977 therefore takes its feed from the foskorite section of the orebody. For the expansion, a third 54 in. by 74 in. gyratory crusher was installed to crush feed for two 32 ft by 15 ft (9.75 by 4.6 m), 9000 hp (6710 kw) autogenous single -stage grinding mills. These units are located near the two existing primary crushers, and the ground ore is pumped 5277 ft (1640 m) to the expanded flotation plant by five stages of centrifugal pumps. The new gyratory is installed in a unique Figure-8 shaped enclosure with the crusher in the smaller 27 ft 11 in. (8. 5 m) diameter cylinder and the maintenance area in the 36 ft 1 in. (11 m) diameter cylinder. Cylinder walls are only 23.6 in. (600 mm) thick because their circular design permits all the concrete to be in compression. A rectangular dump pocket which sits on the smaller cylinder contains two manganese steel faced splitters to protect the crusher spider and countersunk water spray headers under the dumping positions for dust suppression. The dump pocket holds 330 st or 300 mt and is also lined with manganese steel. The crusher is mounted on a reinforced concrete diaphragm over the 363 st (400 mt) crushed ore pocket. In the back of the pocket is plastic pipe. Radioactive level control sources are lowered into this pipe from the crusher support floor. The pipe is protected by concrete covered with steel castings. Level control detectors are mounted on the front wall of the pocket. Liner plates on the crushed ore pocket walls are removed and in- stalled by the use of a circular monorail and trolley mounted on the pocket ceiling. The door in the front of the crushed ore pocket is hinged at the top rather than at the sides and is raised by an electric winch. For removal of the eccentric, rails are installed in the pocket and a unique hydraulically operated cart is moved under the eccentric. A platform is raised to receive the eccentric and lowered so that it may be removed. Crushed ore is removed from the pocket by a hydraulically powered, 8 ft

Jan 1, 1978

By T. E. Ockershauser

The Southwest Antioch Oil Field located in T2&3N - R2&3W, Garvin County, Okla., was discovered in February, 1946, by The Globe Oil & Refining Co. and The Vickers Petroleum Co. at their Melinda Gibson No. 1. Oil production was encountered at a depth of 6,525 ft in 14 ft of lower Pennsyl-vanian sandstone. The producing sand, locally called the ."Gibson" or "Third Deese," is a sand bar deposit strung along the west flank of the Pauls Valley uplift in a northwest-southeast direction. The oil reservoir is defined to the east by the edge of sand deposition along the uplift and to the west by the gradation of sand into shale. Within the Antioch Unit, the sand dips from 150 to 400 ft per mile southwesterly and has a pay thickness varying from 10 to 55 ft and averaging 28 ft. Several areas of Gibson production have been developed, including the Katie pool on the south, the Elmore Area of the Southwest Antioch Gibson Sand pool. the Southwest Antioch Gibson Sand pool proper, the Southwest Maysville pool and the New Hope pool on the north. Production extends over a belt 22 miles long by about two miles wide and is continuous except into the Katie and New Hope pools. It appears that drilling will soon prove these intervening areas productive. To March 1, 1950, approximately 18,000 acres have been developed with 450 Gibson wells. It is likely this count will ultimately reach 32.000 acres with 800 wells. RESERVOIR The natural production of oil from the Gibson reservoir is primarily due to solution gas expansion though gravity also plays a part. There is no indication of water drive or evidence that an initial gas cap existed. Gibson oil has a stock tank gravity of 43" API and was saturated at the original reservoir pressure of 2.925 psi. It contained 1,3440 cu ft of gas per bbl in solution and had a high shrinkage of 70 per cent. Connate water amounts to 15 per cent. Reservoir temperature is 130°F. Porosity averages 15.5 per cent and permeability ranges from less than one md to over 1.000. Based on meacurement of 400 core plugs from 15 wells, 78 per cent of the permeabilities fell within the 10 to 1,000 md bracket and averaged l67. Primary oil recovery is estimated at 140 bbl per acre-ft or 22 million bbl for the present 137-tract unit. Due to unitization

Jan 1, 1951

By Richard McCaffery

THERE has been some discussion among blast-furnace operators regarding the relative merits of tuyeres of the converging type and tuyeres designed in an attempt to produce a diverging jet of air. An article1 on Progress in German Blast Furnace Practice indicates the interest in this subject abroad. This article illustrates a diverging type of tuyere which is shown here in Fig. 1A. The design appears to be rather poor as regards known properties of air flow. The adoption of this. tuyere, the article states, resulted in a decrease of blast pressure of about 4 lb. per sq. in. and an increase of the output of the furnace. If the improvements mentioned are due entirely to the change in tuyere design, the subject of tuyere design seemed worthy of investigation and this paper is a report of such work. Because of the gain in efficiency brought about by the use of a diverging tuyere in the German plant, it was thought desirable to investigate the shape of the air streams issuing from various-types of tuyeres to ascertain whether the gain was due to the tuyere itself or to the distribution of the air in the furnace. Since it is difficult to do experimental work on a full-sized furnace, or even on full-sized tuyeres, and because of the equipment available for the work, it was decided to carry out the work on scale models of tuyeres. Therefore, in this work, single tuyeres were used and the blast discharged into the atmosphere. The shape of the air stream was determined by means of a Pitot tube suitably supported in the air stream at various positions. The air was. furnished by a Roots blower driven by a 10-hp. direct-current motor having field control, and capable of discharging 250 cu. ft. per min. with a pressure on the discharge of 4 in. of mercury. A modern blast furnace with 21-ft. hearth requires about 50,000 cu. ft. per min. of free air at from 16 to 23 lb. per sq. in. pressure, depending upon the type of burden. This pressure is the total pressure required to force the air through the burden and through the tuyeres. Upon computation the pressure drop through the tuyeres is about 1 to 2 lb. per sq. in. By making the tuyeres to a one-fifth scale, and by using a pressure of 1.5 in. of mercury, the shape of the air streams should be

Jan 1, 1931

By Frederick Laist

0. C. RALSTON, Salt Lake City, Utah.-I have merely glanced over this paper, consequently, I am hardly in a position to discuss it intelligently. There is one thing, however, that is of interest, that is, the claim that the oil mixture which they have chosen is the best adapted to the work at hand. I would like to ask Mr. Mathewson if they still feel that that is the case-if that really does give the best grade of concentration and the best extraction for the same money, compared to any particular oil mixture which they could get. E. P. MATHEWSON, Anaconda, Mont.-We are still using that mixture, and we consider it the most economical mixture used. DAVID COLE, El Paso, Texas.-I would like to ask Mr. Ralston if there are some other mixtures that would be better? E. P. MATHEWSON.-We are open to suggestions. 0. C. RALSTON.-My own paper on oils* calls attention to the fact that certain hardwood oils, especially the tars, are now being burned or wasted. A great deal of hardwood tar is available as low as 4 or 5 c. per gallon, that being its value as fuel under the boilers. As a matter of fact, a great deal of testing has been done with only the commercial products that are as a usual ride sold on the market. Very little hardwood tar is sold on the market. In asking a great many people who have tested flotation oils, I have not heard hardwood tar mentioned very often. I think I would add to that that the hardwood tars can probably be bought in quantity comparable with the sludge acid at Anaconda, and. should contain a greater proportion of the frothing constituent, and at a price fairly commensurate with what they pay for the sludge acid. E. P. MATHEWSON.-I would like to make a correction in one statement I made that there has been no change made in the mixture. This change has been made: We found that the amount of wood creosote in treating the sand from tables was extremely small, and we tried some experiments on a large scale, dropping it out and using simply the sludge acid and sulphuric acid. We found that this gave practically as good results as wood creosote. We use wood creosote in treating the slimes. We find it necessary in that operation. DAVID COLE.-I would like to ask, what is sludge acid?

Jan 10, 1916

By Russell G. Wayland

This paper gives the author&apos;s personal idea of the general viewpoint of the world&apos;s largest mica consumer, the U. S. Army, toward the supply, uses, and conservation of mica. However, to cover so broad a subject in a brief paper will require the dismissal of many phases with little or no mention. For example, it will be necessary to omit further reference to phlogopite or amber mica, even though amber block and splittings for certain spark plugs and commutator segments present some supply problems. This paper will deal entirely with muscovite, or white mica. Muscovite Mica Muscovite mica is available commercially in four general forms; namely, as block mica, as splittings, as washer punch, and as scrap mica.1 No strategic importance is attached to washer punch and scrap mica, even though scrap has found some use in military construction and in electrical ceramics. The use of washer punch as such has fallen off with the non-manufacture of household electrical appliances. Some qualities of block mica are also of little or no interest, but other qualities of block mica and all splittings are considered of vital importance. Army equipment requires large amounts of muscovite mica splittings in the form of built-up mica commutator segments and coil insulation in motors and generators. Other military items using significant amounts of muscovite splittings are transformers, switchboards, and blasting apparatus. Flexible mica tape, made from bookform or loose-dusted splittings cemented to paper, linen, glass cloth, and other backing, is widely used in coil insulation in heavy electrical equipment and in aircraft generators. All muscovite mica splittings come from India, principally because of the enormous amount of hand labor required in their preparation. In this emergency, the need for them was anticipated and large industry and government stocks were on hand, while shipments have continued to come by sea in spite of wartime hazards. With the possible exception of certain bookform splittings, no trouble is anticipated in supply. Accordingly, the remainder of this paper is devoted to block (or sheet) muscovite mica, including condenser film that is split from block. The Mica Problem Block muscovite mica is commercially classified into the following general qualitie3, beginning with the best quality: 1. Clear and Slightly Stained (C & SS). 2. Fair stained (FS). 3. Good stained (GS). 4. stained (s). 5. Heavy Stained (HS). 6. Black spotted. The ratio of relative commercial abundance in the present new supply of these micas is approximately 1 C & SS to 4 FS to ro GS to 14 S to whatever the

Jan 1, 1948

By C. E. Berry

Natural stone or manufactured porcelain pebbles are used as the grinding elements in pebble mills and the mills are lined with stone or porcelain blocks. Steel balls usually form the grinding medium in ball mills, and the mills may be lined with steel. Pebble mills are used to avoid contamination by metal of the material being ground, to avoid rapid wear due to corrosion, and for other specialized reasons. Belgian silex (silica) blocks formerly were used widely for lining pebble mills, because of their good resistance to wear, light color, and low cost, but the importation of these blocks was suspended early in the war. The stocks of Belgian silex diminished so rapidly that it was found desirable to compare the properties of a number of domestic substitutes for use in critical operations. Accordingly, a study was made to determine the best substitutes for fine grinding of white pigment and for certain heavy-chemical process work such as the disintegration of phosphate rock in weak phosphoric acid solution. A comprehensive survey of substitute lining materials was not contemplated. It was stipulated at the beginning of the investigation that only materials on the market, available in large quantities, would be tested and that these should be reasonable substitutes from a a ance viewpoint as determined from known physical characteristics. Marble and limestone, for example, could be eliminated immediately. Quartzite, granite and porcelain were selected as likely substitutes for Belgian silex and were subjected to quality tests. Materials Tested 1. Belgian Si1ex.—Sample blocks of a standard grade were taken from crates in which they had been imported. The stone was light gray in color and contained inclusions of small clusters of quartz crystals as well as light colored portions that might be calcite. This was a siliceous rock which appeared to be of igneous origin. 2. Quartzite.—Samples of quartzite were obtained from a quarry in Minnesota. The blocks exhibited a crystalline fracture. The stone was pink in color and composed of fine quartz crystals bound together with a siliceous cement. 3. Granite A was a fine-grained granite quarried in South Carolina. 4. Granite B was coarse-grained granite quarried in South Carolina. 5. Granite C was a coarse-grained granite quarried in North Carolina. 6. Porcelain A.—Sample blocks of the pebble-mill lining material were obtained direct from the manufacturer. It was white in color and of lower specific gravity than the natural materials. It did not have a crystalline structure. 7. Porcelain B.—Sample pebble-mill lining blocks of the porcelain were received direct from the manufacturer. It was white

Jan 1, 1948

By W. F. Hosford

A quantitative explanation is offered for the peculiar curled grain shapes found in the microstructures of drawn wires of bcc metals and compressed aluminum specimens. It is shown that once an [011] fiber texture is developed, the slip system are so oriented that further slip tends to produce plane strain rather than axially symmetric flow of individual grains. With plane -strain flow, however, compatibility of neighboring grains can be maintained only by a bending of grains about one another. PROBABLY the most obvious microstructural feature of heavily worked metals is the distorted shapes of grains. In the course of deformation, the shape change of each grain must be compatible with that of neighboring grains; otherwise holes would be formed at grain boundaries. In analyses of poly-crystalline deformation by Taylor and subsequent workers it was assumed that grain boundary compatability was maintained by each grain undergoing the same shape change as the polycrystalline aggregate in which it is imbedded. According to this assumption, when simple tension or compression is applied to a random polycrystal or to one with a fiber texture, each grain ought to deform with axially symmetric flow. Initially equiaxed grains should become cigar-shaped during wire drawing and pancake-shaped during compression. While microstructural observations of deformed metals are generally in accord with such a picture, certain striking exceptions may be noted. Peck and Thomas5&apos;8 found that grains in heavily drawn tungsten, iron, and niobium (columbium) wires become shaped like ribbons curled about the wire axis, Fig. 1. At a suggestion from the author, they rationalized the development of these micro-structures by considering the orientation of the slip systems in the [011] texture formed by the wire drawing. It is shown in this paper that marked departure from axially symmetric flow of grains is also observed when polycrystalline aluminum is severely compressed. Again the explanation must lie in the orientation of the slip system in the [011] texture, which is formed in fcc metals by compression.&apos; THEORY A simple quantitative argument will be presented to show that the development of these microstructures is a result of flow on the combination of slip systems for which the minimum amount of mechanical work is expended in producing a unit tensile (or compressive) strain. First it must be realized that the macroscopic strains of a crystal resulting from slip are given by: where d dy, and dc, are normal strain increments parallel to the x, y, and z reference axes; are crystallographic shear-strain increments on slip systems

Jan 1, 1964

By Russell G. Wayland

This paper gives the author&apos;s personal idea of the general viewpoint of the world&apos;s largest mica consumer, the U. S. Army, toward the supply, uses, and conservation of mica. However, to cover so broad a subject in a brief paper will require the dismissal of many phases with little or no mention. For example, it will be necessary to omit further reference to phlogopite or amber mica, even though amber block and splittings for certain spark plugs and commutator segments present some supply problems. This paper will deal entirely with muscovite, or white mica. Muscovite Mica Muscovite mica is available commercially in four general forms; namely, as block mica, as splittings, as washer punch, and as scrap mica.1 No strategic importance is attached to washer punch and scrap mica, even though scrap has found some use in military construction and in electrical ceramics. The use of washer punch as such has fallen off with the non-manufacture of household electrical appliances. Some qualities of block mica are also of little or no interest, but other qualities of block mica and all splittings are considered of vital importance. Army equipment requires large amounts of muscovite mica splittings in the form of built-up mica commutator segments and coil insulation in motors and generators. Other military items using significant amounts of muscovite splittings are transformers, switchboards, and blasting apparatus. Flexible mica tape, made from bookform or loose-dusted splittings cemented to paper, linen, glass cloth, and other backing, is widely used in coil insulation in heavy electrical equipment and in aircraft generators. All muscovite mica splittings come from India, principally because of the enormous amount of hand labor required in their preparation. In this emergency, the need for them was anticipated and large industry and government stocks were on hand, while shipments have continued to come by sea in spite of wartime hazards. With the possible exception of certain bookform splittings, no trouble is anticipated in supply. Accordingly, the remainder of this paper is devoted to block (or sheet) muscovite mica, including condenser film that is split from block. The Mica Problem Block muscovite mica is commercially classified into the following general qualitie3, beginning with the best quality: 1. Clear and Slightly Stained (C & SS). 2. Fair stained (FS). 3. Good stained (GS). 4. stained (s). 5. Heavy Stained (HS). 6. Black spotted. The ratio of relative commercial abundance in the present new supply of these micas is approximately 1 C & SS to 4 FS to ro GS to 14 S to whatever the

Jan 1, 1948

By William Marsh Baldwin

[Two of the most useful and important equations available to the metallurgist for the study of plastic deformation of metals are the Huber-von Mises-Hencky1-3 and the St. Venant7-10 equations. HUBER-VON MISES-HENCKY EQUATION The Huber-von Mises-Hencky equation answers the question: When does plastic flow occur in metal that is subjected to a multi-axial stress? It occurs, according to this equation, when the three principal stresses,? al, a2, and a3 satisfy the equation: (s1 - s2)2 + (s 2 - s 3)2 + (s 1 ? s3)2 = 2K2 [I] Here K is the yield strength of the material as determined in an ordinary tensile test. If the quantities a1, a2, and a3 are assigned to the coordinates of a Cartesian three-dimensional system, this expression describes a cylinder whose axis of symmetry is inclined at equal angles to the three coordinate axes4,5 (Fig. I). The radius of this cylinder is v2/3K. For the purpose of simplicity, it is sometimes advantageous to ascribe the values s 1/K = si, s 2/K = s2, s 2/K = s3 to the three coordinate axes instead of the principal stress alone. In this case, Eq. I becomes (s1 - S2)2 + (S2 - S3)2 + (Sl - S3)2 = 2 [2] and the radius of the cylinder becomes 2/3v. In the latter method of representation, a point lying inside the cylinder indicates that the metal will react elastically, whereas a point lying on the cylindrical surface indicates that the metal will behave plastically. Some of the geometric features of this cylinder are worthy of study. Let us inquire first as to what interpretation may be placed upon what we will choose to call the "circles of latitude" of the cylinder (L in Fig. I) and the "meridians" of the cylinder (M in Fig. I). Circles of Latitude Circles of latitude are formed by allowing a plane, passing perpendicular to the cylinder axis, to intersect with the cylinder. Any point, P, on this circle is presumed to have the coordinates s1, s2, and s3. The coordinates of the point resulting from the intersection of the plane and the cylinder axis will be a, a, and a (since the cylinder axis is equally inclined to the three coordi¬nate axes). Let us now pass a line through the point on the circle and the point on the axis.]

Jan 1, 1946

By W. E. Rice

The ceramic industry has to do with forming or molding articles of clay, and imparting to them their characteristic properties of permanence, strength and color by subjecting them to heat treatment in kilns. This heat treatment is commonly known as "firing" or "burning." The art of firing clay ware antedates the industrial use of coal; hence wood was the fuel first used, and the earliest kilns were built to burn wood. The majority of the clay ware produced today is fired in periodic kilns that are essentially enlarged structures similar to the earliest enclosed kilns; a kiln consists of a large chamber 16 to 32 ft. dia. (or rectangular) in which the ware is charged and fired either in direct contact with flame or hot gases from the fuel, or in saggers which shield the ware from direct contact with the gases. The fuel is burned in a number of small furnaces built in the thick wall that encloses the chamber; these furnaces are from 16 to 36 in. wide and from 3 to 5 ft. long; some of them have horizontal or sloping grates, but many have no grates; the last are called "dead-bottom" furnaces. The temperature necessary to mature the charge in the kiln varies for different clays; for some it is as low as 1800°, and for others as high as 2700" F. Wood was an ideal fuel for the low temperatures that were used in early kilns; it burns freely and produces a long, clean flame, which promotes uniform distribution of the heat in the kiln; it does not coke and so restrict the passage of air through the fuel bed; the ash does not melt in the fuel bed to form clinker; and the ash that is carried into the chamber and deposited on the charge does not contain iron and sulfur to discolor the clay. The extent of the ceramic industry now precludes the general use of wood in kilns, so that today this industry is one of the large users of bituminous coal, burning more than eight million tons annually in kilns. Manufacturing plants usually are at or near the source of clay, with deposits of coal suitable for kilns occurring near the clay. The cost of coal is the largest single item of expense in the manufacture of clay ware, and, because all coals are not equally suitable for the process, the careful selection of coal is important. In this selection the desidera-

Jan 1, 1932

By C. E. Berry

Natural stone or manufactured porcelain pebbles are used as the grinding elements in pebble mills and the mills are lined with stone or porcelain blocks. Steel balls usually form the grinding medium in ball mills, and the mills may be lined with steel. Pebble mills are used to avoid contamination by metal of the material being ground, to avoid rapid wear due to corrosion, and for other specialized reasons. Belgian silex (silica) blocks formerly were used widely for lining pebble mills, because of their good resistance to wear, light color, and low cost, but the importation of these blocks was suspended early in the war. The stocks of Belgian silex diminished so rapidly that it was found desirable to compare the properties of a number of domestic substitutes for use in critical operations. Accordingly, a study was made to determine the best substitutes for fine grinding of white pigment and for certain heavy-chemical process work such as the disintegration of phosphate rock in weak phosphoric acid solution. A comprehensive survey of substitute lining materials was not contemplated. It was stipulated at the beginning of the investigation that only materials on the market, available in large quantities, would be tested and that these should be reasonable substitutes from a a ance viewpoint as determined from known physical characteristics. Marble and limestone, for example, could be eliminated immediately. Quartzite, granite and porcelain were selected as likely substitutes for Belgian silex and were subjected to quality tests. Materials Tested 1. Belgian Si1ex.—Sample blocks of a standard grade were taken from crates in which they had been imported. The stone was light gray in color and contained inclusions of small clusters of quartz crystals as well as light colored portions that might be calcite. This was a siliceous rock which appeared to be of igneous origin. 2. Quartzite.—Samples of quartzite were obtained from a quarry in Minnesota. The blocks exhibited a crystalline fracture. The stone was pink in color and composed of fine quartz crystals bound together with a siliceous cement. 3. Granite A was a fine-grained granite quarried in South Carolina. 4. Granite B was coarse-grained granite quarried in South Carolina. 5. Granite C was a coarse-grained granite quarried in North Carolina. 6. Porcelain A.—Sample blocks of the pebble-mill lining material were obtained direct from the manufacturer. It was white in color and of lower specific gravity than the natural materials. It did not have a crystalline structure. 7. Porcelain B.—Sample pebble-mill lining blocks of the porcelain were received direct from the manufacturer. It was white

Jan 1, 1948