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By G. B. Pryde, R. M. Magraw

In laying out a new mine, provision should be made for the ultimate recovery of as much coal in any given bed as is consistent with safety and economic mining. Though each mining district, if not each individual mine, has problems that make the adoption of any hard and fast rule impossible, certain basic principles are adapted to practically all conditions. One of the most vital is the provision for barrier pillars of ample dimensions to protect all haulage and permanent airways during the life of the property. Where conditions permit, room or butt entries should be driven on the strike or slightly to the rise, and rooms turned at right angles to these entries. The width of rooms and room pillars is governed by conditions prevailing in the mines under consideration. A safe rule is: In advancing, extract not more than 25 to 35 per cent. of the entire seam; in exceptionally thick seams, considerably less than 25 per cent. should be taken. Rooms usually vary in length from 250 to 350 ft. (76 to 106 m.) with a barrier pillar of not less than 80 ft. between the last crosscut. in rooms and the back entry of the level above. All entries, rooms, and entry-and-room crosscuts should be driven .on sights and room crosscuts should be driven at, right angles to the direction of the rooms. In mines under excessively heavy cover or where roof conditions are bad, rooms should be driven narrow and a barrier pillar left at every fifth to tenth room. This barrier should be of such dimensions that one or more rooms, with pillars of usual dimensions, may be turned through it when the barrier is no longer required. Two of the advantages of such a barrier are the protection of the panel against peaking of roof load during pillar extraction and the easy closing of the entry in case of fire. Where economic conditions permit, it is preferable to follow the retreating panel system of mining. In the case of coal that outcrops, and even in cases where no outcrop is exposed, it is preferable to commence pillar extracting on the high side of the mine. Where the retreating

Jan 1, 1922

By H. E. Stauss, E. I. Salkovitz, F. W. von Batchelder

EXISTING information regarding the structure of a spherulite in nodular cast iron is based on optical studies. According to these data, a nodule consists of an aggregate of graphite crystallites radiating from the center, with the closely packed basal planes at right angles to the radii. The c axes lie along the radii. This view faces some uncertainty in the fact that the c axis does not represent the accepted direction of fastest growth in graphite. To supplement the optical information, X-ray studies have now been made. The principle used was to screen the nodule in greater part from the X-ray beam and expose only a minor cap. As successively larger portions of the nodule were introduced into the X-ray beam, any differences in the X-ray patterns could be observed. Such photographs have been taken with chromium radiation and a Laue camera. The graphite nodule itself, about 0.010 to 0.025 in. in diam, was mounted with vaseline on a micrometer screw for control of the linear motion. The nodule rotated about 45" each time that it was translated linearly. The nodules were obtained from magnesium-treated hypereutectic iron by electrolytic solution of the iron in hydrochloric acid. In Fig. la is shown the pattern of the thinnest cap examined. In Fig. lb is shown the pattern of the same nodule moved 0.003 in. farther into the X-ray beam, and rotated 45" at the same time. Figs, la and lb indicate incomplete circles for graphite (the two outer circles arise from graphite) with the side arcs much weaker than the top and bottom ones. The arcs obtained are themselves not continuous in intensity but vary with maxima of intensity some 15" and 30" apart. The structure of the nodule that would give rise to such a pattern can be explained as follows. Basically the nodule consisted of small crystallites. The discontinuous character of the diffraction rings demonstrates that the nodule was not composed of randomly oriented crystallites. The strong vertical reflections and the weak lateral reflections show that the reflecting planes were roughly normal to the radii. The absence of sharp reflection spots suggests that the nodule did not contain large crystals. The sharpness of the diffraction rings in their radial direction shows that the variations in intensity along the arcs were not the result of line broadening resulting from extremely small crystals. In the diffraction patterns two rings corresponding to graphite were found. The third and inner ring in the figures originated in the vaseline. The graphite rings correspond to the a and ß lines reflected from the basal planes, showing that the radii of the nodules are the [0001] direction normal to the basal planes of graphite. The picture of the structure that is formed is, therefore, one of aggregates of crystallites. Within each aggregate the c axes of the crystallites tend to align themselves in the radial direction of the nodule, although these axes deviate somewhat in direction by a continuous variation of angle. Correspondingly the basal planes of the graphite crystallites are generally normal to the radii. It is a pleasure to acknowledge the assistance of M. C. Bloom and R. P. Dunphy of this laboratory.

Jan 1, 1952

By A. S. Malicsi, I. Iwasaki

The removal of hydrophobic coatings of flotation collectors from iron ores becomes of interest when a duplex flotation process is considered for upgrading, when a pelletizing process is considered for a concentrate floated with a fatty acid or a soap collector, or when a disposal of froth products from cationic silica flotation is of environmental concern. Ozone can oxidize organic compounds rapidly, thereby removing the hydrophobic coatings of flotation collectors. Ozone is widely used for treating and purifying drinking water, waste water treatment, and for chemicals processing (Murphy and Orr, 1975; Rice et al., 1980). Its uses in metallurgical operations, however, are very sparse (Allegrini et al., 1970; Chernobrov and Rozinoyer, 1975; Ishii et al., 1970; Iwasaki and Malicsi, 1985; Matsubara et al., 1978). Yet, its high reactivity and the absence of potentially hazardous byproducts become of interest in destroying flotation reagents adsorbed on mineral surfaces or remaining in mill water for recycle or for discharge. Duplex Flotation A duplex flotation process, as applied to oxidized iron ores, would involve a fatty acid flotation of iron minerals followed by an amine flotation of the siliceous gangue from the rougher iron concentrate. Such a process has been used in the Florida phosphate fields. Fatty acid coatings cannot be removed as readily with a simple acid or alkali treatment from iron oxide surfaces as from Florida phosphates. A combination of reagents, such as lime and quebracho, lime and alkali phosphate, or sulfuric acid and oxalic acid, has therefore been proposed. In a previous article (Iwasaki et al., 1967) , the use of activated carbon was found to be effective in removing fatty acid coatings both in the duplex flotation and the pelletizing processes. The use of ozone offers another approach to the removal of fatty acid coatings from iron oxide surfaces. To investigate the possible application of the duplex flotation process, a specularite ore from Michigan analyzing 36.5% iron was used. A 600-g (1.3-1b) sample was ground in a laboratory rod mill together with 250 g/t (0.5 lb per st) of sodium silicate to -150 µm (-100 mesh). This was transferred to a Fagergren laboratory flotation cell, and deslimed four times at 20 µm (quartz equivalent). The deslimed pulp was transferred to a laboratory conditioner, diluted to 40% solids, and conditioned with 250 g/t (0.5 lb per st) of soda ash and 250 g/t (0.5 lb per st) of oleic acid. The conditioned pulp was then transferred back to the Fagergren cell, floated until barren of froth, and the rougher froth product was returned to the cell and cleaned. The results are presented in Table 1. The cleaner concentrate at this point analyzed 45.3% Fe. The cleaner concentrate coated with fatty acid was transferred to a 2-L (0.53-gal) beaker. While the pulp was agitated with a glass T-stirrer, ozone was bubbled into the agitated pulp for 15 minutes at a rate of 10 mg/min (0.00035 oz per min) ozone (250 g/t or 0.5 lb per st 03 feed). It was observed that the pulp ceased to froth after about 10 minutes. The amine flotation of siliceous gangue from the ozonated pulp was carried out first by conditioning with a dextrin, a commonly used starch depressant for iron oxides. This was followed by flotation with a stage addition of an ether amine at increments of 100 g/t (0.2 lb per st). Three stages were required to float the siliceous gangue to near completion. The three froth products were combined and cleaned twice. When the cationic flotation Rougher, Cleaner 1 and Cleaner 2 cell products were combined, an iron concentrate analyzing 64.5% iron was obtained at an overall iron recovery of 72.8%. Pelletizing Fatty acid flotation concentrates have been pelletized successfully in northern Michigan mills. But at other locations, fatty acid coatings on iron flotation concentrates proved so undesirable in agglomeration that other methods of concentration had to be sought. For example, a sinter mix containing iron ore concentrates upgraded by fatty acid flotation resulted in decreased productivity. This occurred because the micropellets of particles with the hydrophobic coating are less tolerant of moisture. Thus, the bed permeability is lost (Beebe, 1965). The agglomeration of concentrates obtained by the fatty acid flotation alone, and the hydrophobic coatings destroyed by ozonation or by the duplex flotation process, is not expected to cause any difficulty since the surfaces of the concentrates would be hydrophilic. Removal of the fatty acid coating with activated carbon, indicated by the loss of floatability, was shown to restore the decrepitation temperature of wet balls during drying cycle (Iwasaki et al., 1967). Disposal of Cationic Silica Flotation Froths Recent demands of iron blast furnaces place the silica content of the magnetic taconite pellets at about 5%. Conventional process for magnetic taconite involving fine grinding and magnetic separation often produces magnetic concentrates analyzing in excess of 5% silica. This is due to the presence of the middling grains of siliceous gangue and magnetite. Cationic silica flotation of magnetic taconite concentrates (DeVaney, 1949) may be used to reduce the silica content. But the amine coating on siliceous gangue becomes of environmental concern when the flotation tailings are discarded in tailing ponds.

Jan 1, 1986

By C. D. Hunter, J. B. Browning

During the year 1934, Kentucky oil and gas operators have partly overcome their past depression fears and in the oil industry, with possibly more abandonments of old oil producers than the completion of new oil wells, produced 4,814,904 bbl. of oil in 1934 against 4,501,511 bbl. in 1933. In the gas industry of eastern Kentucky, 115 gas wells were completed during 1934. This production is delivered through two 20-in., one 16-in., one 12-in., one 10-in., and two 8-in. pipe lines to supply both domestic and industrial markets in Cincinnati, Ohio; Louisville, Lexington, Frankfort, Winchester, Ashland, Covington and other Kentucky towns; Washington, D.C., and other eastern cities. The largest percentage of these gas wells and production are from the Devonian black shale area of Floyd, Pike, Knott, Martin and Magoffin counties, Kentucky. In this area the largest percentage of 1889 wells, developing 421,-215 acres, has been completed in the past 10 years, of which 55.3 per cent produce from the 400 to 550 ft. of Carbonaceous Devonian black shales. The successful results obtained from these Devonian shales are due to the physical effects of the 5000 to 6000 lb. of gelatinated nitroglycerin with which the entire 400 to 550 ft. of shale is shot. A very small number of the shale wells are natural producers and do not require shooting. Other than the Devonian shale gas production, the remaining 44.5 per cent of the gas in this field is encountered throughout the entire strati-graphic section above this horizon; namely, salt sands of Pennsylvanian age and Maxon, Big Lime and Weir of Mississippian Age. A very small percentage is encountered in the Corniferous Devonian lime and the Silurian Big 6 below the black shales. In western Kentucky, in the counties of Henderson, Webster, Hopkins, McLean, Christian, Muhlenburg, Ohio, Daviess, Hancock, Brecken-ridge, Hart, Barren and Warren, many gas wells have been completed, but, because of insufficient market, activity has been somewhat desultory. The area is served by the pipe lilies of the Kentucky Natural Gas Corporation, with headquarters at Owensboro. Their market is increasing and the gas is delivered to Owensboro, Henderson, Madisonville, and many

Jan 1, 1935

By L. M. Barker, E. G. Lewis

THE literature of milling is replete with papers devoted to the subject of ball milling, all of which no doubt have contributed in one way or another to progress in that art. In this paper reference will be made to only a few of the many authors, but the value of the contributions of all who have written on that subject is hereby acknowledged. With a few exceptions the efforts of most students of the subject have been devoted to laboratory investigations of principles. Davis1 was one of the first to report on plant-scale investigations and to present to mill men certain criteria for the guidance of ball-milling practices. His conclusions with respect to the significance of sizing analyses of classifier sands in their relation to the factors of mill speed and ball sizing are particularly referred to. Those conclusions were: I. If the balls are large or the speed of the mill is high, crowding will appear at the finer sizes in the classifier sands. 2. If the balls are small or the speed is low, crowding will appear at the coarser sizes in the classifier sands. 3. The indications are that best efficiency is obtained when the screen analysis of the sands show a minimum crowding at any size. The last conclusion was qualified by the statement that it had not been proved conclusively. It is surprising, however, that the literature of later years reveals little evidence that millmen have made any serious attempt to apply those criteria. This may, perhaps, be explained by the fact that the average plant-scale ball-milling problem presents so many variables that an investigation of any one of them encounters the problem of control of the others-a problem that often is unsurmountable in a small plant. In a large plant, in which there is a duplication of grinding units in parallel operation, opportunity may be afforded for determining the value of such criteria. Nevertheless, a study of published data from grinding circuits of both large and small plants suggests that either Davis' criteria have been tried and found inapplicable or have never been given consideration. For the purpose of testing Davis' conclusions and with improvement of ballmilling efficiency as the final objective, a test program was initiated in the concentrator of the New Cornelia branch of the Phelps Dodge Corporation early in 1938. The practices of that plant have already been described.2 The fine-grinding units are arranged so that any one of eight units may be operated as a test unit and its results compared with those of the remaining units. All units receive similar feed from a common storage bin, in which the product of the fine-crushing plant is bedded by traveling tripper. The ball mills are all similar in size and operated at the same speeds, and are individually metered. The feeder conveyors of each unit are equipped with Merrick weightometers. The test program as initially outlined proposed investigation of the following:

Jan 1, 1941

By E. Teghtsoonian, K. G. Davis

Cobalt crystals of commercial purity have been tested in tension. Their resolved shear stress-shear strain curves are very similar in form to those for zinc, magnesium, and cadmium. There is an initial linear region for shear strains up to around 150 pct, the ratio of work hardening slope to shear modulus at room temperature being about 2 X x This is followed by an upturn, which is, PLASTIC deformation in metal single crystals with close-packed structures has been found strongly dependent on stacking-fault energy. The high stacking-fault energy hexagonal metals magnesium, zinc, and cadmium have been quite extensively tested, but up to now no data have been available for a comparable hexagonal metal with low stacking-fau1t energy' An however, smaller in magnitude for cobalt than for the other metals. Values for the critical resolved shear stress rise from 97 kg per sq cm at room temperature to approximately 170 kg per sq cm at -196 °C. The Cottrell-Stokes ratio is not constant either for variations in the strain rate or for temperature changes, its value decreasing with strain. investigation into the plastic deformation of cobalt, which has a very low stacking-fault energy, has therefore been undertaken. EXPERIMENTAL PROCEDURES Cobalt crystals in the form of rods 0.3 cm in diam were grown in an electron-beam floating-zone refiner at a rate of zone travel of 25 cm per hr. Details of the growing procedure are given in Ref. 1. The zoned cobalt rods had the following analysis:

Jan 1, 1963

The housing of labor and sanitation at mines in India are difficult problems to solve because-no more than two or three castes will accept the same conditions, and conditions suitable to one coal-field are not applicable to other fields. It is also necessary to consider the financial standing of the different companies. The European companies, which pay 30 per cent. and more dividends, can erect more suitable houses than the Indian companies, which are just able to keep their heads above water. The Santhal will not live in a bucca-roofed house as a permanent dwelling, and both the Santhal and Koras have an aversion to living in a line of attached huts. They have forsaken a whole, line of houses in one of which a case of sickness or death has occurred, and those houses were afterward considered unfit by all other classes of natives. The Santhals, Koras, and Douri castes will not take drinking water from a stand pipe; wells must be furnished. When well water is not available, these people will take water from the nearest pool or tank regardless of whether or not the water is stagnant. The well tops should not he completely enclosed, nor should there be a drain around the top. The ground should slope away from the well. In the Girieih coal fields, the miners have a great objection to pucca floors; they prefer earth which is lapped, easily cleaned, and renewed. As it is customary for the miner to build his own house, the company supplying the roofing material, he takes a special interest in it, keeps it in order, and hesitates to leave it. Each house is surrounded by its own bit of land, which the inmate cultivates.

Jan 12, 1918

By Roberto Fernandez

Want of knowledge on the part of experts from abroad respecting the amalgamation-system, known as the Mexican or patio process, has been the cause in this country of trouble to many foreign mining companies. This process has not been looked upon by their managers as a satisfactory method of treating silver-ores, and they prefer to employ others, which, although more modern, and often more profitable in other countries, have not proved to be so under the exceptional conditions of this country, where labor is cheap and paid in silver, while fuel is very dear. The cause of this error of judgment is probably the inexact information which has been furnished by several authors respecting the economical results of the patio process. This treatment is not suitable for silver-ores of every kind. Simple sulphides of silver are best adapted to it, and, next to these, the combinations of complex sulphides, viz., pyrargyrite, polybasite, stephanite, proustite, etc. Chlorides, bromides and iodides of silver are considered rebellious ; argentiferous galena, blende, bournonite, as also argentiferous arsenical pyrites of iron and copper, are absolutelg unsuited to this treatment. Experience has proved that high-grade ores do not give as satisfactory results as those of mediurn grades, as, for instance, carrying from 1 to 2 kilos of silver per metrical ton. The patio process, as actually practiced in this district, comprises the following operations: 1. The ore is crushed in a dry state in a roller-mill, reducing it to pea-size, from which uniform samples, and, in consequence, correct assays, can be obtained. 2. It is then thrown into the arrastra, and pulverized with water, so fine that it will pass through an 80-mesh screen.

Jan 1, 1900

By T. L. Loucks, E. T. Guerrero

Pressure drop characteristics in a system composed of two adjacent concentric regions of different permeability were studied. The differential equations for continuity of mass flow in the two regions were solved using the Laplace transformation and the necessary boundary conditions to give the pressure distribution in the composite reservoir, the resulting equation for pressure drop at the inner boundary was evaluated for a variety of composite reservoirs and compared with the results for a uniform reservoir. From this study it was found that under certain conditions the permeability in both zones, as well as the size of the inner zone, can be determined from the pressure drop curve. INTRODUCTION The theory for the pressure distribution and pressure build-up behavior of a well producing a single, slightly compressible fluid from infinite and finite homogeneous reservoirs was presented by Hornerl and Miller, Dyes and Hutchinson.2 Extensions on this original work to provide improved and extended interpretations and better agreement between theory and observed results have been made by Matthews, et a1,3 van Everdingen,4 Gladfelter, et al5 Stegemeierand Matthews,6 Hurst and Guerrero,7 and Perrine.8 More recently Lefkovits, et al,9 studied pressure build-up behavior in bounded reservoirs composed of stratified layers. Houpeurtl0 has suggested various approaches to the general problem of variable permeability and porosity but presented no analytic solutions for particular permeability variations. Albert, Jaisson and Marionll studied the finite composite reservoir and presented numerical solutions to the unsteady-state case and an analytical solution valid only for large times. They also studied the so-called pseudo-steady state for several examples of radial permeability variations. Very similar examples have been treated in the unsteady state with application to pressure build-up by Loucks in an unpublished manuscript. More recently Hurst12 has presented the complete point-sink solution (valid for all times) for the infinite composite reservoir. He applied these solutions to interference between oil fields along with an even more elegant application of his explicit solution to the material-balance equation including water influx. Mortada 13 approaches the same application by avoiding the point-source limitation but gives the solution for the aquifer region which is valid only for large times. Hopkinson, Natanson and Temple14 have treated both the finite and infinite composite reservoir obtaining the pressure distribution for the inner zone valid for large times. This paper presents a theoretical study of the pressure distribution in an infinite composite reservoir composed of two adjacent concentric regions of different permeability. The object was to determine the manner in which pressure drop at the inner boundary of a composite reservoir depends upon time, the permeability of each zone and the size of the inner zone. Expressions for the pressure distribution in both zones are developed which take into account the radius of the sink and are valid for small times as well as large times. It was felt that an understanding of the pressure drop behavior in various composite reservoirs would be of assistance in the interpretation of some pressure build-up curves which do not behave according to the theory derived for uniform systems. Often the region surrounding the wellbore is either more permeable or less permeable than the reservoir because of the various drilling and completion practices. The effects of reduced permeability due to drilling-fluid invasion and of increased permeability due to fracturing or acidizing need to be more carefully defined. Therefore, an equation for the pressure drop in a composite reservoir was developed, and the effects of both the permeability in each zone and the size of the inner zone were studied. STATEMENT AND SOLUTION OF PROBLEM BOUNDARY CONDITIONS AND ASSUMPTIONS The physical system studied was a composite

By Joseph P. Hodgson

JOSEPH P. HODGSON.-As to ".Safety First," I did not deal with that, but I will say that in 1913, the number of .men killed was nine, and that year the "safety first" program was commenced; the next year, 1914, the number was reduced to five. In 1915, I am pleased to say that the number was reduced to two in the Copper Queen's entire property, and we have none so far this year. THE CHAIRMAN (G. F. G. HERMAN, Bisbee, Ariz.).-I can say, further, that we have from eight to nineteen men per month incapacitated for more than 14 days. Those are classified in this State as serious accidents. The number of men injured has apparently increased, -but that is clue to our improved method of recording and classifying accidents, no matter how slight. C. W. GOODALE, Butte, Mont.-The importance of cooperation among the members of the staff of an industrial organization is well brought out by Mr..Hodgson's paper.

Jan 12, 1916

By Laurance Reid

HIGH compression ratios, resulting from high injection pressures and relatively low recovery process pressures, constitute a major problem, which has confronted those engaged in gas recycling for condensate production since the beginning of that practice. Despite the numerous process developments and improvements, no entirely satisfactory solution for this prob-lem has been presented to date. Often, where the residue gas from the recovery process must be recompressed for subsurface injection, there is a substantial difference between the required injection pressure and the plant-operating pressure required to produce maximum recovery of condensate. These limitations result in high compression ratios, which, in turn, neces-sitate excessive compressor investment and operating cost. As an alternative, the operating pressure may be increased in order to lessen the compressor requirements but such a saving often is purchased at the expense of decreased condensate recovery, caused by operation at the higher pressure. Regardless of the choice, the net result is a diminished return on the capital invested in the project. The goal of future development in this field must be the complete recovery of all valuable hydrocarbon components in the reservoir fluid at pressures that, regarded as compressor suction pressure, will require minimum compressor horsepower to inject the residue gas into the formation. A com-pression ratio of 1.5 has been established as an optimum for modern compressor equipment." Therefore, in order to con-form to this optimum condition, a 3000-lb. injection pressure would require that the condensate recovery process be operated at 2000 lb. per sq. inch.

Jan 1, 1940

By G. F. Comstock

In the literature of metallography there is a large amount of material describing the various non-metallic inclusions found in iron and steel, and the appearance of sulfides, silicates, oxides, or alumina in steel under the microscope is fairly well known. The inclusions found in non-ferrous metals are, however, not so well known, at least judging from published writings, and the author has been interested in examining small castings of copper, brass, or bronze with certain inclusions purposely mixed with the metal, to see what was the characteristic appearance of each kind of inclusion, and if they could be readily distinguished from one another. The method employed in most cases consisted in overheating and oxidizing a small charge of copper, then cooling it somewhat, and adding a suitable amount of the element whose oxide it was desired to observe. This element was stirred in well and given time to react with the oxygen in the copper, then the melt was poured in a sand mold in the form of a cylinder about 21/2 in. (63 mm.) in each dimension, with a sprue about 11/2 in. (38 mm.) in diameter and 3 in. (76 mm.) high on top of the cylinder, the sprue forming the only riser. Samples for examination were cut sometimes from the center of the casting, and sometimes from the sprue or riser. A few of these samples were cast in chill molds. The appearance of sulfides was studied in an alloy containing 10 per cent, each of tin and lead, with which a flux of plaster of Paris was used. The appearance of foundry sand was studied in several alloys, one of them having sand stirred into the metal intentionally, and others having cut into the molds badly when poured, so that the castings were spoiled by included sand. As all this work was done on alloys having copper as the chief ingredient, the natural starting point was copper oxide, the appearance of which in a micro-section is well known. Cuprous oxide is soluble in molten copper, but separates out in freezing and forms a eutectic containing 3.5 per cent. Cu20, or 0.39 per cent. oxygen. If there is less

Jan 1, 1919

By Fred Bond

WHEN some materials are ground dry in a ball mill, a stage of comminution is reached at which the finely divided particles begin to adhere to the balls and to the mill lining. As grinding progresses, a coating accumulates upon the grinding media, which tends to cushion the impacts and thus retard reduction of the material, and finally becomes so thick that all grinding ceases. At this stage, the characteristic noise produced by the grinding media dur-ing normal mill operation changes to a dull, muffled sound. In most instances, the formation of the coating marks the practical limit of size reduction. Industrial requirements for fine grinding frequently meet with this obstacle, and the tendency in many com-mercial operations to grind materials to a higher degree of fineness than formerly makes the solution of this problem an im-portant one. The phenomenon is of far greater importance, therefore, than the limited amount of research and technical discussion devoted to it implies. In order to learn more about the coating of different materials when ground dry to a high degree of fineness, certain labora-tory tests were made from which it was found that different materials form coat-ings at widely different size distributions. It is probable that most materials will coat if they are ground fine enough; the exceptions have inherent lubricating qual-ities, like coal and graphite.

Jan 1, 1940

By Oliver B. Hopkins

Peruvian production for the year 1935 amounted to 17,064,879 bbl., a record amount for any year, bringing the cumulative production of the country up to 188 million barrels. The 1935 figure is an increase of 785,769 bbl. over the 1934 total. The property of the International Petroleum Co. contributed 636,812 bbl. of this increase, and the Lobitos property 158,625 barrels. Exploration work in the country was again active, with attention focused on three areas, the Huallaga River, Lake Titicaca and the Coastal Zone of the Province of Tumbes. It is reported that in the Huallaga River area the Selden Breck Construction Co. has completed geological and engineering studies on its Pachitea River concessions and has ordered a drilling rig. In the Lake Titicaca region further studies in the vicinity of Pusi were made by Government geologists. During the period from 1906 to 1915, the Pirin anticline in this area produced 285,936 bbl. of low-grade crude. The Government holds 120,000 hectares of reserved lands in this area. In the Coastal Zone of the Province of Tumbes explorations by the Government were continued on the National Reserve, and a test location has been selected in the Quebrada Zapotal about 10 miles from the Port of Zorritos. An order has been placed in the United States for drilling equipment. LaBrea-Parinas Estate.—Production on the LeBrea-Parinas Estate reached an all-time high in 1935 of 14,756,914 bbl., an increase of 636,812 bbl. over the 1934 record. The total production from 1890 to 1935 was 148,541,523 bbl. During 1935 a total of 63,021 ft. was drilled in new wells and 5449 ft. in deepening existing wells; 23 wells were deepened and 29 new wells were completed, of which 27 were producers and 2 were dry holes. At the end of the year 2873 wells had been drilled on the Estate, of which 1838 were still productive. The remaining 1035 wells represent abandoned producers or dry holes. Practically all the drilling on the property has been done with cable tools, but during 1934 three strings of rotary tools were introduced. Experience with these outfits has shown that rotary equipment can

Jan 1, 1936

By Oliver B. Hopkins

Peruvian production for the year 1935 amounted to 17,064,879 bbl., a record amount for any year, bringing the cumulative production of the country up to 188 million barrels. The 1935 figure is an increase of 785,769 bbl. over the 1934 total. The property of the International Petroleum Co. contributed 636,812 bbl. of this increase, and the Lobitos property 158,625 barrels. Exploration work in the country was again active, with attention focused on three areas, the Huallaga River, Lake Titicaca and the Coastal Zone of the Province of Tumbes. It is reported that in the Huallaga River area the Selden Breck Construction Co. has completed geological and engineering studies on its Pachitea River concessions and has ordered a drilling rig. In the Lake Titicaca region further studies in the vicinity of Pusi were made by Government geologists. During the period from 1906 to 1915, the Pirin anticline in this area produced 285,936 bbl. of low-grade crude. The Government holds 120,000 hectares of reserved lands in this area. In the Coastal Zone of the Province of Tumbes explorations by the Government were continued on the National Reserve, and a test location has been selected in the Quebrada Zapotal about 10 miles from the Port of Zorritos. An order has been placed in the United States for drilling equipment. LaBrea-Parinas Estate.—Production on the LeBrea-Parinas Estate reached an all-time high in 1935 of 14,756,914 bbl., an increase of 636,812 bbl. over the 1934 record. The total production from 1890 to 1935 was 148,541,523 bbl. During 1935 a total of 63,021 ft. was drilled in new wells and 5449 ft. in deepening existing wells; 23 wells were deepened and 29 new wells were completed, of which 27 were producers and 2 were dry holes. At the end of the year 2873 wells had been drilled on the Estate, of which 1838 were still productive. The remaining 1035 wells represent abandoned producers or dry holes. Practically all the drilling on the property has been done with cable tools, but during 1934 three strings of rotary tools were introduced. Experience with these outfits has shown that rotary equipment can

Jan 1, 1936

By T. T. Read

A SHORT time ago, one of the large steel companies courteously furnished the author with detailed records of the operations of a considerable number of iron blast furnaces over a period of two months. These will be made the basis of a subsequent study, but in beginning this study one of -the first points requiring consideration was the probable error of the records, for what otherwise might be regarded as significant differences of performance under different conditions were perhaps really due to errors of observation, or failure to observe and record variations. If it is assumed, in blast-furnace records and calculations, that known quantities or factors are constant, when as a matter of fact they are variable, the effects of these variations may erroneously be ascribed to some other cause. This is quite clearly expressed in the following quotation from E. Buckingham:1 Theory always operates on an ideally simplified picture of reality because real phenomena are unmanageably complicated. The results obtained are not exactly true for any, real phenomenon, though they may be for an ideal one; and the approxi¬mation with which a theoretical equation, however obtained, represents the actual facts, always depends on the approximation in essentials between the ideal picture and its real prototype. The purpose of dimensional reasoning is to find out how some quantity which is involved in the phenomenon under consideration is related to certain others; or to find the relation connecting two or more quantities which vary, or may vary, simulta-neously during the course of the phenomenon. Since we know that we must have a complete equation to start with, we begin by thinking the matter over, to see whether the quantities we have in mind are the only ones involved. Usually it is evident that they are not; so we next make a list of all the quantities we can think of which might under any circumstances be important. Upon considering this list, which is often a long one, it is usually evident that under the actual circumstances a number of these quantities may safely be ignored; so we cross them off the list and thus pass from our most general conception of the phenomenon to an ideal simpler one, in which these quantities are not involved at all.

Jan 3, 1925

By Richard Pearce

I am deeply sensible of the honor you have conferred on me in electing me your president for this year. It is difficult to understand why I have merited such distinction at your hands, except that I may possibly have helped, in some small way, in the develop ment of metallurgical practice in the West. I fear, however, that I shall fall far shirt of the expectations you may have in regard to my fitness for such a position. The responsibility of preparing an address for this occasion has caused me considerable thought and anxiety. Unlike my predecessors in office, many of whom have dealt in their presidential addresses with subjects covering a wide field, which they could survey with the confidence born of their own extensive knowledge, I have been confined by my experience, during the last twenty-five years, almost wholly to that portion of metallurgical science which bears especially on the treatment of gold and silver. Yet perhaps some sort of general review of the progress of this branch of metallurgy in the West, besides being the contribution I feel myself best qualified to offer, may prove acceptable to many of the members of the Institute. Some few of the gentlemen present will remember the crude condition of metallurgical practice as it was conducted in Colorado only twenty-five years ago. My own personal experience covers a period of eighteen years; and during this comparatively short time I have seen the most astonishing changes in the conduct of metallurgical works. In all probability the marked progress which this country has exhibited could hardly be reached anywhere else, and this result has been achieved mainly by the activity and enterprise so characteristic of the men of the West. The first little successful attempt at smelting made at Black Hawk, in 1867, by Ex-Senator N. P. Hill, representing the Boston and Colorado Smelting Company, proved a great boon to the miners,

Jan 1, 1890

By Julien F. Phillips, Donald E. Garrett

The production of soda ash from natural sources is one of the United States' oldest industries. The London Company, which financed the settlement of Jamestown, in the fall of 1608 exported in its first cargo from Virginia " . . . trials of pitch, tar, glass, frankincense, and soap-ashes."1 This last product, a crude mixture of sodium and potassium carbonates obtained by the burning of wood in iron pots, was the commercial soda ash of its day, used in the infant soap, glass, and bleaching industries. Besides having a good cash value, its production helped to clear the land, and it was a compact, easily shipped commodity. The extra high potassium content of these American "pot-ashes" gave them an added market as a fertilizer, a field that they dominated until the opening of the Strassfurt deposits in 1860. This form of natural soda ash disappeared forever from commercial importance with the introduction of the Le Blanc process (1791), and later the Solvay process for manufacturing soda ash. The Solvay process was rapidly accepted in the United States, and has accounted for most of the country's soda ash production since 1884. It was not until the western part of the country began to be developed that natural soda ash was again produced. A number of lakes, playas, and springs west of the Rocky Mountains were found to be rich in this mineral, and climatic conditions were ideal for its easy recovery by solar evaporation. The production of natural soda ash from these deposits has become a steadily growing industry in the United States. Production A summary of the production and value of natural sodium carbonates in the United States is presented in Table 1. Prior to 1927 the principal output came from several different companies at Owens Lake, California. Then production at Searles Lake, California, began to [ ] increase until it became the most important source. In 1948 the sale of crude trona from Green River, Wyoming, commenced and since that time production from these latter two areas has been about equal. Table 2 lists the four

Jan 1, 1960

By J. E. Campbell, H. E. Parkinson, Y. P. Chugh

Miner-bolters, which combine mining and bolting functions into a single machine, are being developed by the US Department of Energy to improve production and productivity in coal mining operations. The authors have been studying possible production gains from the use of the Joy automated miner-bolter (AMB) in mine development using the computer simulation model "UGMHS" developed by the Pennsylvania State University. In a recent paper (Chugh, Campbell, and Parkinson, 1979) the authors discussed justification for the development of miner- bolter machines, assumptions and analytical procedures used in computer simulation, cutting, and bolting cycle times for an AMB, and production potential of AMB in four and five entry mine development sections. The effects of available operating time, haulage capacity, bolt installation time, and flush and staggered entry layouts on production potential of AMB were also discussed. In all cases, the production potential of AMB was compared to a full face continuous miner and an independent dual-boom roof bolter operating in a similar mine layout. Present Study In this study, the production potential of the Joy AMB in three and six entry layouts is presented. A three entry mine layout represents development entries in a longwall panel. A six entry layout represents development of main and submain entries in longwall mine development. Flush and staggered entries were considered in both layouts. The assumptions and analytical procedures used in this study were similar to those in the earlier study and are not presented in this paper. Only the results of the studies are presented here.

Jan 1, 1984

By Joseph Kelly

DEPLETION of anthracite resources in Lackawanna County, Pennsylvania, has forced the recovery of coal tracts formerly considered unminable. Chief among these are the large areas of outcrop coal lying on a heavy pitch on the mountain sides, abandoned thirty or forty years ago as too costly and too hazardous to mine. The old companies, in many instances, stopped their chambers 80 or 100 ft. hack from the actual outcrop, and then dropped back another 100 ft. before starting to rob the pillars, thus leaving large areas of coal. Recovery of this coal naturally leads to mining hazards not encountered years ago. The first step is to sink a slope from the surface with the pitch of the vein, and then drive counters across the pitch as close to the robbed area as proper protection for the lower side of the -counter will permit. Next, the old chambers are advanced or new ones driven in the solid, as the conditions require. As these chambers approach the outcrop the real safety work begins-that of preventing the miner from being buried or locked in by an avalanche of mud.

Jan 1, 1936