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Discussion of the paper of GEORGE S. RICE and H. H. CLARK, presented at the Pittsburgh meeting, October, 1914, and printed in Bulletin No. 94, October, 1914, pp. 2563 to 2571. NORMAN V. BRETH,* Pittsburgh, Pa.-It was my privilege to visit in the last two months on behalf of the U. S. Bureau of Mines 10 mines where electric shot-firing systems controlled from outside the mine are installed. I will describe briefly what I saw in some of these mines, which are located in Utah, New. Mexico, Oklahoma, Alabama, and Kansas. At a mine in Utah, 230-volt alternating current is used to fire the shots, which is taken from a small transformer in the substation. The shot-iring circuit is independent of all other wires and is tested for grounds every day. There are no lightning arresters on the firing circuit. Porcelain insulators are used inside of the mine, and glass outside. The switches are situated as follows: One in the substation, one in, the shot-firer's cabin, two at each cross entry; where the shot-firing circuit crosses the trolley wire a switch is placed on either side of the entry in series with the shot-firing circuit. The miners are checked in and out of the mine. The coal is undercut and is shot down with permissible explosive, the shots being connected in multiple. There are 75 to 110 shots fired each day. A great many times there are no missed shots. If not more than two or three are missed they are left until next day. The fan is kept running at full speed when the shots are fired. The shot-firing switch is closed only once and the whole mine is shot at once. At another mine in Utah, power wires are used for shot-firing circuits; 500-volt, direct current is used to fire the shots. The only sizes of wire used outside of the power wires are Nos. 8 and 14 B. & S. gauge. The return is connected to the pipe lines and track. Porcelain insulators are. used inside of the mine.

Jan 4, 1915

By William D. Mayercheck

Introduction of continuous mining machines in the late 1940s created a new production bottleneck in room-and-pillar sections-the shuttle car. While continuous miners could cut and load coal at a nearly constant rate, the mining sequence was repeatedly interrupted as fully loaded shuttle cars changed places with empty ones. This wait-for-the-shuttle delay period forced the coal industry to reassess the shuttle's batch-type procedure with an eve toward continuous haulage systems that would allow uninterrupted coal flow from face to portal.

Jan 7, 1979

K. Baumgarten has returned from active service in France. He reports that he saw C. W. Campbell, formerly with the 2d Engineers on the Chateau Thierry front, and believes that the latter returned to the United States on August 1. He also saw J. J. Croston; G. J. Sielaff, recently transferred to the Gas Service; Thomas M. Smither, survivor of the Tuscania after a 10-mile swim to Ireland. While in Paris he en-deavored to see Prof. Sauveur, but was unsuccessful. F. K. Borrow was given a commission as Lieutenant in the Royal Garrison Artillery in 1914, but had to relinquish it, on account of ill health, in August, 1915. His health has much improved and he hopes to resume active work toward the end of this year. Davis, A. W:, see British Columbia Engineers, below. Alfred Fox, Jr., enlisted in the Public Schools Brigade, Royal Fusiliers, in September, 1914; was gazetted Lieutenant in the Royal Field Artillery in December, 1914, promoted to Captain in November, 1915, and Adjutant to 78th Brigade, Royal Field Artillery, in January, 1916. He was appointed Staff Captain of the 12th Divisional Artillery in November, 1917. He has served continuously in France since July 1, 1915. He was awarded the Military Cross in January, 1917, and four times mentioned in despatches. E. Fraser-Campbell writes that he joined the London University 0. T. C. in January, 1918, for five weeks; enlisted with the Argyll and Sutherland Highlanders in February, 1918, and attended a training course for officer cadets at Chatham for six weeks. He was commissioned 2d Lieutenant, Royal Engineers, in April, 1918. After two months on home training at Chatham, he landed in France on June 23, 1918, posted to 180th Tunnelling Co., R. E., and is now with his unit up on the line.

Jan 10, 1918

By L. J. Erck, T. E. Ban

A discussion of laboratory procedures used to determine pellet quality and to simulate handling and firing conditions. Strength- temperature relationships in pelletizing; effect of chemical additives on agglomeration; and crushing, abrasion, and impact resistance of the pelletized products are discussed with respect to five different iron ore concentrates.

Jan 8, 1953

By R. A. Burton, J. T. Hansford, D. A. T. Donohue

Substantial evidence indicates that many petroleum producing horizons contain naturally occurring, ordered fracture systems and that within a particular geologic zone, vertical fractures induced in wellbores often will be directed along a particular compass direction. Both conditions will seriously alter the fluid displacement behavior within reservoirs. In this study the effect of induced fracture orientation and length on sweep efficiency is determined for a five-spot pattern. In general, it is assumed that all wells are fractured and directed along the same compass direction. Using the electrical analog to steady state, two-dimensional fluid flow in porous media, boundary conditions are obtained from which flood fronts are tracked numerically. The numerical computations require a particle tracking routine for approximating flood front histories. It is shown that recovery is sensitive to the length and orientation of fractures for the pattern studied. with the proper design of fracture-pattern systems, recovery can be enhanced considerably. INTRODUCTION Hydraulic fracturing introduced in 1949l gave the industry a rather inexpensive means of increasing the fluid injection or production capacity of wells. It has been used with particular success to increase the production rate of wells completed in tight formations, such as in western pennsylvania2 where producers have fractured in depleted or near-depleted fields and observed economic responses. Once the natural energy declines in such a reservoir where all wells have been fractured, waterflooding is generally suggested as means of further increasing recovery. Of the dual objective sought in waterflooding — high injectivity and high breakthrough sweep efficiency — the former condition can be obtained if all wells in the flood pattern are fractured; the latter condition should depend on the nature of the fracture system. Considerable theoretical work has been published on the nature of fractures induced in boreholes.3-5 Although discussion persists concerning the possibility of forming a horizontal fracture at a given point within the wellbore, it is generally conceded that only vertical fractures will develop below a given depth, i.e., where the fracturing Pressure is less than the overburden load. Given the fact that fractures will be vertical in most cases of interest, it is also important to know whether there is order to fracture orientations within a given geological region. Kehle has suggested that in tectonically relaxed areas of uncomplicated geology, the stresses are fairly uniform and all fractures in the region should be parallel.5 Dunlap arrived at a similar conclusion in a theoretical investigation of localized stress conditions surrounding the borehole.6 He concluded that most vertical fractures are propagated in a preferred azimuthal direction. Fraser and Pettitt, in extending these theoretical suggestions to a specific field case, used an impression packer to record both a vertical fracture and the orientation of this fracture in the wellbore of a well in the Howard Glasscock field, Tex.7 Use of this information enhanced the waterflood recovery of the field. Anderson and Stahl also used impression packers on three fractured wells in the Allegheny field. N. Y.. and found that the fractures were oriented more or less along the same compass direction.8 Orientation of the fractures in this manner depends on the stress condition within the formation during fracturing. Elkins and Skov have demonstrated that a natural, oriented, vertical fracture system exists within the Spraberry field? Heck suggests

Jan 1, 1969

By Richard P. Rothwell

REVOLING slime-tables with stationary sprays and oscillating brushes have for many years been a favorite apparatus used for working slimes in German dressing-works, often displacing Rittinger tables and the many variations of Cornish buddles. The difficulty of building these tables larger than 5 1/2 meters (17 feet) in diameter, increasing the cost and making them unwieldy, rendered it necessary also to concentrate the slimes in several operations, because the travel over so short a length of hearth would not suffice for close concentration. A preliminary sizing is effected in a system of spitzkasten. Herr C. Linkenbach, general manager of the Ems Lead and Silver Works, Germany, devised a buddle, in 1878, which has since worked well and found much favor in Germany, and has been in one instance copied here, at Colorado Springs, without any credit having been given to the original inventor. Linkenbach's plan has been to reverse the functions of the table and the washing apparatus of the old German revolving table. He makes the tables stationary and rotates the washing apparatus,, thus enabling him to save in power, and, within certain limits, to increase the dimensions of the table, without in any way affecting its durability or materially increasing its cost. In its earlier form, the buddle was single, and that type is still

Jan 1, 1883

By Toshiki Hayashi, Shoichi Asahina, Kenitsu Hosokura

Sumitomo Metal Mining Co., Ltd.'s Kunitomi Smelter has been treating in the blast furnace copper concentrate containing bismuth. The bismuth is concentrated in the electrostatic precipitator dust and the converter dust. Bismuth contained in the converter dust is leached by a mixture of salt and sulfuric acid, and is then recovered by a cementation process using scrap iron. The bismuth cake thus recovered and the electro- static precipitator dust are reduced to crude bismuth metal which is further refined to a high purity bismuth metal by the pyrometallurgical refining process. Details of this process are elaborated in this report.

Jan 1, 1976

By R. Gibala

Internal-friction measurements on hydrogen-charged iron over the temperature range 4° to 300°K are reported. Two relaxation peaks, the hydrogen Snoek peak at 48 °K and the hydrogen cold-work peak in the range 145" to 2200K, are observed at 80 kc per sec. The effects of hydrogen-charging, aging, and deformation on the internal-friction results are determined and are used to show evidence of partitioning of hydrogen between solid solution and dislocations. The hydrogen-dislocation binding energy is estimated from the behaviors of the relaxation tiwzes and relaxation strengths of the Snoek peak and the cold-work peak. Its value is approxi,mately 6400 cal per mole. MANY investigators have demonstrated the usefulness of internal-friction measurements in determining the manner in which interstitial impurities interact with dislocations in bcc metals. Part of this success has resulted from the existence in bcc interstitial alloys of two anelastic relaxation peaks—the Snoek peak' and the cold-work or Koster peak2 (designated hereafter by SP and CWP, respectively). The SP has its origin in the redistribution of interstitials in solid solution among sites made energetically nonequivalent by an applied stress. The rate at which the redistribution occurs, measured by the relaxation time for the process, is related in a simple way to the diffusion rate of the interstitial in the free solution. The relaxation strength is proportional to the concentration of interstitial in solid solution. The CWP appears to have its origin in the relaxation of an interstitial-dislocation complex for which the relaxation time at a given temperature is much longer than that for the SP. The relaxation strength depends strongly on the concentration of interstitial and the amount of deformation at relatively low concentrations and deformations.2-8 From the dependence of the relaxation strength on interstitial concentration, the SP and CWP may serve as measures of the concentrations of interstitials in free solution and bound at dislocations, respectively. Thus their behaviors have been used to investigate interstitial-dislocation interactions in Fe-C, Fe-N, and several refractory metal systems.'-' However, the Fe-H system has not been studied extensively,? even though disputes in recent years over the mechanism of hydrogen embrittlement in steels involve argument over the extent to which lattice hydrogen and hydrogen-dislocation interactions play an important role.?-'' Previous work on Fe-H indicates the internal-friction behavior to be qualitatively consistent with that for other systems. Apparently, both a SP and a CWP are observed in the temperature ranges 30" to 50°K and 100°to 140°K, respectively (at 1 cps). However, there is neither sufficient nor accurate enough information to identify convincingly these peaks with their supposed counterparts in other systems. Nor have there been any attempts to make quantitative use of these peaks to study hydrogen diffusion, aging, or interaction processes. In this paper, an attempt is made to obtain more complete information on internal friction of hydrogen in iron than presently available. Internal-friction measurements in the range 4° to 300°K on hydrogen-charged iron show that the two peaks discussed above are in fact the hydrogen SP and CWP. Several effects of hydrogen charging, aging, and deformation on these peaks are observed and are used to determine the partitioning of hydrogen between solid solution and dislocation sites in iron. EXPERIMENTAL Materials. The starting material for this investigation was a high-purity iron supplied by National Research Corp. as a 1-in.-diam rod. The following analysis was given (inwt pct): C, 0.004; N, 0.0003; 0, 0.007; P, 0.002; S, 0.005; Si, 0.006; Mn, 0.001; Cu, 0.002; Ni, 0.005; Cr, 0.001; Mo, 0.001. After an initial vacuum anneal (-5 XTorr) at 700°C, the rod was cold-

Jan 1, 1968

By Richard H. Rein, John Chipman

Liquid slags of the system SiO2-Ca0-MgO-A1~03 were equilibrated with liquid Fe-Si-C alloys in graphite or Sic crucibles at 1600°C in pure CO gas at atmospheric pressure, and the silicon content of both phases determined. Ternary slugs of the systern SiO2-CaO-A12O3 were also studied at 1550°C. The silicon content of the metal phase saturated with both graphite and SIC is 22.0pct at 1550°C and In the iron blast furnace, as in nearly all carbon-reduction processes, some silicon is transferred from slag to metal. The importance of this reaction is enhanced by its indirect effect on the transfer of sulfur from metal to slag, and this has stimulated a comprehensive research program on the equilibrium distribution of silicon between slag and metal. Earlier studies'-3 of this same problem provided data for calculation of the thermodynamic activities4 of the components in SiO,-CaO-A1,O3 slags. 22.4 pct at 1600°C. The temperature at which the phases cristobalite, gvaphite, $ SiC, liquid slag, Fe-Si-C alloy, and CO gas at 1 atm pressure can coexist in equilibrium was found to be 1533°C. The results agree well with earlier studies. They are shown graphically as lines of constant silicon cmtent in the metal which also are lines of constant SiO, activity in the slag.

Jan 1, 1963

By George F. Learning

TOTAL DIRECT IMPACT The uranium mining industry's principal economic impacts on the Texas economy are the result of three flows of money from the industry into the remainder of the state's economy. These three are: (1) money paid to individuals (personal income) ; (2) money paid to other businesses (business income); and (3) money paid to state and local governments (government revenues). As these direct payments from the uranium industry to various other sectors of the Texas economy subsequently circulate and recirculate within the state, the indirect effects of uranium mining's direct impacts multiply to reach amounts significantly higher than the direct income flows alone. Over the past decade, the uranium mining industry has substantially increased its role as a provider of jobs, personal income, business income, and government revenues in Texas. The growth has come almost exclusively in a largely rural, seven-county area that lies within the triangle formed by the Laredo, San Antonio, and Corpus Christi metropolitan areas. The uranium mining industry, in fact, has been the major dynamic element in this rural area despite relative stagnation in most of the region's other basic economic sectors. Over the three years from 1976 to 1978, the South Texas uranium mining industry directly contributed a total of $115 million to the economy of the seven- county region in which it operated and $164 million to the economy of the entire state of Texas. In 1979 alone, the total direct contribution of the industry to the Texas economy had climbed to $124 million in personal, business, and government income. PERSONAL INCOME IMPACT In the period from 1976 through 1978, the South Texas uranium mining industry provided an average of $12.5 million in personal income each year directly to residents of Atascosa, Bee, Duval , Karnes, Live Oak, McMullen, and Webb counties -- the seven Texas' counties that make up the South Texas Uranium Belt. A1 though 84 percent of this resulted from the employment of area residents in uranium industry jobs, some amounts were also provided by the payment of rents and royalties to land owners for the use of their land and mineral rights in uranium mining operations. In 1979, the uranium industry provided approximately $38 million to residents of the Uranium Belt and the rest of Texas. This was more than double the average of $16.1 million provided to Texas residents during the 1976 to 1978 period. The full importance of the uranium industry as a source of personal income, however, should not be reckoned merely by the amount of wages and salaries that it pays directly to its own employees, nor by its rent and royalty payments paid directly to land and mineral rights owners living in Texas. The added payments that the industry makes directly to other Texas businesses and state and local governments in Texas are themselves converted into personal income as those business firms and government units in turn pay their employees. All of the direct income payments made by the uranium industry circulate and recirculate within the state's economy, multiplying their impact as they go, until they eventually all leak out of the state as federal taxes or as payments to individuals or businesses located outside of Texas. The combined circulation and recirculation of the direct personal, business, and government income that was provided by the-uranium industry in Texas during 1976, 1977, and 1978 resulted in an average annual amount of indirect personal income of more than $83 mill ion. This alone was $20 mill ion more than the industry's average annual sales during the same years. The total of combined direct and indirect personal income contributed to the Texas economy by the uranium mining industry in that same three-year period thus averaged almost $100 million annually. In 1979, the amount of indirect personal income contributed to the Texas economy by the circulation of uranium mining's direct contributions had risen to about $196 million, more than double the average of the previous three years. The combined direct and in- direct personal income impact in 1979 thus amounted to $234 million. BUSINESS INCOME IMPACT The income provided directly to other Texas business firms through the purchase of needed goods and services by the uranium industry has been twice as big as the industry's payrolls. In 1976, 1977, and 1978, the South Texas uranium industry spent an average of almost $36 million each year to buy both goods and services from other Texas businesses. By 1979, this direct contribution to the Texas economy had swollen to $76 million. The biggest share of the uranium industry's payments to other businesses have gone to contracting firms, including both construction firms and those providing specialized mining services. In the past four years, about 40 percent of the direct payments made by Texas uranium producers to other Texas firms have been to contractors. Texas wholesale and retail firms have also shared in the business sales provided by the South Texas uranium mining industry. Over the past four years, Texas wholesale and retail trade businesses have accounted for about 34 percent of the uranium mining industry's purchases from other Texas businesses. Public utilities firms have received another six per- cent, while Texas manufacturers and transportation firms have accounted for about five percent each. The other sectors of the state's economy, including other mineral industries, agriculture, finance, insurance, real estate, and services, have accounted

Jan 1, 1980

By Ralph J. Schilthuis, William Hurst

The nature of the forces that are important in producing the oil in the East Texas field and the manner in which these forces are affected by the rate of production have always been problems of outstanding interest. These questions are of great interest to the industry as a whole on account of the economic importance of the East Texas field and to the engineers in particular on account of the unique character and behavior of the field. Subsurface pressure data throughout the field have been collected systematically, so that a quite complete history of the reservoir pressures has been kept as the field has been developed and produced. Subsurface samples of the oil and gas have been taken and these have been examined to obtain data on the physical properties of the reservoir fluids under the actual conditions of temperature and pressure. All of these data have been valuable because they have afforded the basis for a careful study of the means by which the oil is produced. It is the purpose of this discussion first to point out several of the important facts revealed by the data mentioned and then to describe studies that have been made concerning the interpretation of these facts. Reservoir Pressure Data and Properties of Oil The reservoir pressure data on the East Texas field have shown conclusively that the pressures are readily affected by changes in the rate at which the field is produced. This can well be seen in Fig. 1, where the average reservoir pressures obtained from time to time are plotted with the daily production rates and the cumulative production of the field. It is noted that the average reservoir pressure has declined irregularly, depending upon the rate of production, from the estimated original value of 1625 Ib. per sq. in. to the value of 1228 lb. per sq. in. observed for Aug. 11,1934. The decline in pressure has been more rapid at the higher rates of production than at the lower rates. In contrast, the average reservoir pressure has increased, on several occasions, upon reduction of the withdrawal rate from a high value to a lower value. The reservoir pressure data have also shown that a definite gradient in pressure has existed across the field from west to east since the begin-

Jan 1, 1935

By William H. Kobbé

The word recovery as used in this paper is applied in its broader sense and not limited to wells producing from horizons of unconsolidated sands. Certain problems connected with the winning of petroleum from such horizons present themselves while drilling is in progress and should be considered before drilling is commenced wherever unconsolidated sands are expected. Maximum recovery depends not alone. upon efficient pumping methods but also upon the selection of a proper drilling system and the completion of a well especially adapted to the extraction of these oil-bearing sands. 11. DRILLING Determining Factors in Selection of Method The selection of a drilling method for the development of a region in which the oil reservoir consists of unconsolidated sands is based on the following considerations: (1) Character of the formations overlying the reservoir; (2) thickness of the oil-bearing stratum or strata; (3) thickness and character of water or gas sands; (4) gas pressure to be encountered or expected; (5) total depth of well. 1. Character of the Formations Overlying the Reservoir The strata overlying the reservoir may consist of beds of shales, clays, sands and other soft materials, or they may be slates, limestones and sandstones consolidated to all degrees of hardness. Very often the overlying strata are predominantly of soft materials but interbedded with harder formations. Likewise, soft strata are encountered at different horizons in an overburden consisting almost entirely of the harder sedimentaries. The physical character of this overburden is frequently

Jan 1, 1917

By Charles Malcolmson

AN elaborate series of experiments has been conducted during the past three years at Irvington, N. J., which has resulted in the perfection of a process for the manufacture of smokeless fuel from high-volatile coals, and for the recovery and refinement of the coal-tar products derived therefrom. These experiments have been financed by Messrs. Blair Co., of New York, and were conducted under the direction of Charles H. Smith, a member of this Institute, and the inventor of the process. The low-temperature distillation of coal has interested investigators for many years. Sporadic attempts have been made to solve the mechanical problems, but until the Smith process. was developed, they were not carried to conclusions of economic value. The present coal shortage and the increasing demand for smokeless fuels make this subject one of timely interest.

Jan 5, 1918

By Roy Hardy

THE Getchell mine is a comparatively recent discovery in the old Potosi mining district, Humboldt County, Nevada, a district organized in the seventies and eighties, in which some prospecting was done in several metamorphic zones along a monzonite-sedimentary contact. The district had no production in the early days and no further work was done until the same metamorphic zones were prospected for tungsten (scheelite) in 1917 and 1918, when a few small lots were shipped. It again lay dormant until 1934, when prospectors investigated a large siliceous escarpment at one end of the old district where outcroppings were a prominent feature of the topography. Undoubtedly, during the early prospecting of the district, the outcroppings had been investigated for mineral, probably by panning, with negligible results because the gold later found is invisible in the concentrate and is refractory. A fire assay revealed the presence of sufficient gold to warrant develop-ment work. The outcroppings were easily prospected by short tunnels having their portals in the siliceous material on the hanging-wall side, with a maximum distance to crosscut to the footwall of 135 ft., or a distance at right angle to dip of 60 to 90 ft. Development work, reaching a depth of over 600 ft. on the dip of the vein, was done by means of various crosscut tunnels, winzes and laterals. A churn-drill hole was also sunk, which intersected the vein at a depth of 1100 ft. on the dip. Sufficient development work of this character was completed by 1937 to justify the erection of a reduc-tion plant to roast the sulphide ore and cyanide the calcine, and to treat the oxidized ore by straight cyanidation, to make a doré bullion for shipment to the mint. The erection of the plant was started that year and finished early in 1938, with a combined capacity of about 800 tons per day. It has operated continuously since erection and recently was enlarged to handle 1000 tons per day. The vein dips with the slope of the mountain, and by stripping the hanging wall the ore may be mined by power shovel for several hun-dred feet below the outcrop. Thereafter underground methods will be necessary.

Jan 1, 1940

By E. B. Hunt, T. M. Geffen, C. R. Stewart, V. J. Berry

Laboratory data .show that the gas-oil ratio performance of non-uniform porosity limestones produced by solution gas drive is sensitive to producing rate and to fluid properties. Nan-uniform porosity limestones are those for which laboratcry solution and external gas drive tests yield considerably different relative permeability ratio characterislics. The oil recovery performance by solution gas drive depends directly on the number of gas bubbles formed. Laboratory rates of pressure decline, which are 100 to 10,000 times greater than normal field rates. cause the formation of an unusually large number of gas bubbles. This results in abnormally high oil recovery efficiencies. Since it is impractical to reproduce the number of bubbles formed under field conditions, laboratory solution gas drive data on non-uniform porosity limestones are therefore not directly applicable to field operations. However, certain laboratory data can be used to make a conservative estimate of field performance. The concepts presented in this paper indicate the possibility that increased field oil recoveries may he obtained from non-uniform porosity limestones by rap- idly reducing reservoir pressure for a short interval of time. It has yet to be established that significant improvements in oil recovery from such reservoirs can he realized by varying the pressure decline rate within limits possible in the field. However, the possibility that recovery may be increased in this manner warrants further study. INTRODUCTION Limestone reservoir rocks can be divided into two general classes according to the nature of their pore space. One class has a comparatively uniform pore system composed mainly of voids between grains of the rock (intergranular type porosity). The other class, in addition to having intergranular porosity, has a secondary pore system composed of combinations of solution cavities, fractures, etc., and is considered to have non-uniform porosity. It has been shown in a previous publication' that the laboratory measured gas-oil flow behavior of uniform type porosity limestones is essentially the same for a test simulating a field solution gas drive as for one simulating an external gas drive. For non-uniform porosity type limestones a significant difference in gas-oil flow behavior was found. More efficient behavior was

Jan 1, 1955

By Horace Winchell

SCOPE OF DISCUSSION THE laws here referred to Are those which define the status of the prospector for mineral deposits in the soil or beneath it, establish his methods of procedure, protect him in his possession while searching for the subterranean treasures, and give him assurance of title when all required conditions have been fulfilled and valuable minerals discovered. Regulations for the operation of mines and the safety and health of mine employees are likewise subjects of Federal and State legislation, but are not within the scope of the present program. Various features of our present laws will be discussed in detail by able students of the subject, and specific remedies will be proposed for the most glaring defects. It is my purpose to present in this paper a summary review of the reasons why revision is needed and demanded by the great majority of those in daily contact with the industry.

Jan 4, 1914

By Charles R. Simcoe

It was pointed out in a recent paper'g that the initial flow stress of as-quenched martensite is very low even in an alloy steel with an M, well above room temperature. It was also shown that the high ultimate tensile strength resulted from a very high rate of work

Jan 1, 1967

By L. P. Bayvel

The method of spectral transparency was investigated. A device for measuring particle sizes based on this method was developed, tested and applied. The device affords measurements of particle size distribution in the range from 0.1 to 4 µm. It proved possible to measure sizes not only of spherical particles but also of non- spherical ones. The spectral range in which it is necessary to determine transparency for particle size measurements was found.

Jan 1, 1980

By P. F. Richardson, J. L. Perisho, W. J. Roe

Handling and transport of coal during the winter months can be a severe problem. The inability to unload frozen coal from rail cars produces serious economic and logistic problems due to transportation delays, rail car shortages, and demurrage on the rail cars. One method of dealing with the problem of unloading frozen coal has been to spray freeze conditioning agents onto the coal before it is loaded into rail cars. Both water soluble and oil based formulations have been used as freeze conditioning agents. The water soluble treatments generally contain a polyhydroxy alcohol, such as ethylene glycol, or salts of alkaline earth metals, such as magnesium chloride and calcium chloride, as freeze point depressants. The oil based treatments consist principally of hydrocarbons, such as No. 2 oil or diesel fuel. The authors' tests have shown significant differences in the effectiveness of these freeze conditioning agents, depending on the particular coal substrate being treated. These differences correlate with the coal porosity and inherent moisture of the substrate. In general, the greater the porosity of the coal, the smaller the effect of the freeze conditioning agents. Coal porosity has a greater impact on water soluble freeze conditioning agents than oil based products. The authors investigated the pore structure of a variety of coals using mercury intrusion. Findings were related to the effectiveness of different freeze conditioning agents as measured by unconfined compression strength tests. In general, coals with a large number of very small pores (between 0.05 µm and 0.03 µm) do not respond as well to freeze conditioning chemicals.

Jan 1, 1986

By John V. Beall, William F. Haddon

A long the mighty Andean Cordillera, there is splendor beyond imagination-in the natural beauty of the mountains and in daring engineering and lavish investment in the mines. This is the story of the great copper mines of Chile and Peru. Each mine has a special quality which has tested the physical and spiritual resources of the founder. In the early days of the older mines, the mining engineer of song and story was more the rule than the exception. He was physically tough, ingenious and a leader of men. In the current political and social environment of Chile and Peru, the foreign contract mining engineer is still needed; but he must be a different type of man. To John J. Selters at Cerro's Rio Blanco, the principal ingredient is still "toughness," but it is "toughness of mind" that is needed. "He probably should be a teacher." The copper mines are not new. They were, almost without exception, worked by Indians (La Exotica might prove the rule), and later by the intrepid Spaniards. Modern mining began after the turn of the century. In Chile, the first of the big ones was the Braden Copper Co. founded on the El Teniente deposit. This development was followed by Chile Exploration Co. at Chuquicamata and Andes Copper at Potrerillos. These properties have been developed over the years by vast expenditures of money and a monumental amount of labor. None was free of technical problems-metallurgy at Chuqui, marginal grade of the old mine at Andes, avalanches and the great fire at El Teniente. The evolution which has brought the established mines of Chile, and the new ones coming on stream, to their present state of development is in reality the work of wonders of input-money, engineering and responsible management in an atmosphere of political stability. Without any one of these, the result would have been failure.

Jan 11, 1969