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By E. H. Crabtree, T. G. Chapman, V. W. Winters

IN 1939 one of the authors* described advances in carbon-cyanidation for the period 1932 to 1939 • T. G. Chapman: A Cyanide Process Based on the Simultaneous Dissolution and Adsorption of Gold. Trans. AIME (1939) 134, 207. and included: (1) the dissolution of gold in an ore pulp by cyanide and its simultaneous adsorption by carbon, (2) the stage addition of adsorptive carbon and its movement countercurrent to the flow of the ore pulp, and (3) the recycling of adsorptive carbon. Considerable additional experimental and pilot plant work have been done by the authors since 1939 and the results of such work E. H. CRABTREE, JR., Member AIME, is Director of Milling, Eagle-Picher Mining and Smelting Co., Miami, Okla., V. W. WINTERS is Superintendent, Sahuarita Concentrator, Eagle-Picher Mining and Smelting Co., Tucson, Ariz., and T. G. CHAPMAN, Member AIME, is Dean, College of Mines, University of Arizona, Tucson. AIME Sun Francisco Meeting, February 1949. TP 2744 B. Discussion (2 copies) may be sent to Transactions AIME before March 31, 1950. Manuscript received March 3, 1949. have been sufficiently encouraging to justify a second paper. Developments from 1939 to 1948: In 1941, Verne W. Winters did the first experimental work in eliminating agitation during dissolution and adsorption and thereby demonstrated that the dissolution of gold by cyanide and its simultaneous adsorption by carbon take place essentially to completion in a stagnant pulp. Shortly thereafter, and as a result of the stagnant pulp experimental work, Winters and Chapman demonstrated that soluble gold, in a cyanide ore pulp, would migrate from the ore pulp through a perforated container and be adsorbed by carbon within the container. During the same year, the Eagle-Picher Mining and Smelting Co. erected a 25-ton capacity pilot plant at the Harquahala mine about 9 miles from Salome, Ariz. Experimental work at this plant comprised chiefly the stagnant pulp modification of carbon-cyanidation although considerable work was done in the grinding and activation of carbon, and testing various methods of extracting adsorbed gold from carbon. Soon after the completion of the Harquahala

Jan 1, 1951

By Edward H. Robie

NEVER before have the annual company reports in the mineral industry field exhibited the typo-graphical art so abundantly as does the current crop. Time was when most company reports made a drab appearance and dry reading, mostly confined to financial data and text that gave little information to the public or technical men. Now, the dollar statistics assume less importance. Considerable information is given on what is going on at the company's plants, new equipment being installed, new methods, properties under development, ore reserves and grades, and similar information of interest to professional men working in the field. We have one suggestion for further improvement: The names of the officers and directors of the company are always given, but only a few companies give the names of the principal operating officials. We think, in the case of a mine for example, that the name of the general manager, his assistant, the mine and mill superintendents, and any other top operating officials who have been largely responsible for the success of operations, are worthy of mention. The reports are now widely read and this recognition is due them. Conspicuous among the annual reports that we happen to have seen, in point of typographical attractiveness, are that of the Texas Co., celebrating its fiftieth anniversary with a gold-plated cover and gold printing inside; and that of Noranda Mines Ltd., with a red and black cover that would attract attention anywhere. Comment on economics, taxes, and labor give an excellent picture of what our industry is facing. Consider the following, from the report of the Union Oil Co. of California:

Jan 1, 1952

By Richard B. Moore

The successful commercial production of helium during the last few years has added greatly to its scientific interest. When the quantity of an element available for experimental purposes increases within a few years by 200,000 per cent., both public and scientific interest in the element are greatly stimulated. Before the war, probably, there was not more than 10 or 15 cu. ft. of helium in existence. The larger part of this was owned by Prof. Kam-merlingh Onnes, and was used by him in connection with his low-temperature work at Leiden. By experimental work during the war and immediately afterwards, the Canadians, under Prof. J. C. McLennan, produced about 60,000 cu. ft. of helium of various grades of purity. Up to Dee. 1, 1921, when the plant at Fort Worth was shut down because of lack of funds, there had been produced during the experimental work by the U. S. Government, during the war and afterwards. 2,300,000 cu ft. of helium averaging between 92 and 95 per cent. purity. After the new appropriation was made in 1922, the production plant was again started and at the time of writing was making about 15,000 cu. ft. of helium a day. Only three of the five units were being operated because of the inability to get sufficient gas to run at full capacity. The gas supply is owned by two companies and on account of a disagreement between them, it has been possible for some time to get gas from only one. It is expected that when all five units are running steadily, the daily production will be between 30,000 and 40,000 cu. ft. of gas averaging from 93 to 95 per cent. purity. All three experimental plants used during the war have been shut down. The Air Reduction plant, using the Claude system, and the Linde

Jan 1, 1923

By C. A. Hartnagel

In 1939 the production of crude oil in New York totaled 5,105,000 bbl. This marks the third consecutive year production of crude oil has exceeded 5,000,000 bbl. and only once has this total been surpassed—in the year 1882, three years after the discovery of oil in Allegany County, when the annual production was more than 6,000,000 barrels. The most gratifying feature of the industry was the increased demand for lubricants, which resulted in advanced prices for crude. From a price at the beginning of the year of $1.68 per barrel, six advances totaling 82c brought the year's closing to $2.50 per barrel. A further increase in price on Jan. 1, 1940, to $2.75 per barrel places the local industry in a strong position for the year's operations. Most of the oil production of the state is now obtained by water-flooding, and the industry is practically stabilized. No new pools have been discovered in over 25 years, and border drilling indicates little prospect of extending the boundaries of the fields beyond their present limits. Deep drilling to the Oriskany sandstone in and close to the present oil fields hay failed to find oil in substantial amounts. Altogether, the oil pools of New York have produced during the 60 years that they have been exploited approximately 125,000,000 bbl. of oil. Following the flush production of 1882, the annual production gradually dccrcased and the year 1912 marked an all-time low of only 782,000 bbl. In 1919, as a result of flooding operations, a definite upward trend in oil production was recorded. During that year also the production of oil by water-flooding methods as approved by Legislative action. In the 21-yr. period beginning with 1919, oil production in the state ha.: totaled 60,338,000 bbl. Thus it will be seen that by the aid of flooding methods nearly as much oil has been produced in the last 21 yr. as in the preceding 40 yr., although the Iatter period included the flush production in 1882. As there is little hope of extending the area of the present producing oil fields of the state, producers and refiners are concerned regarding the future life of the fields. It is encouraging to observe that earlier esti- Published by permission of Director of New York State Museum, Albany, N. P. Summarized at meeting; manuscript received at the office of the Institute March 20. 1940.

Jan 1, 1940

By Rossiter W. Raymond

I DESIRE to call the attention of the Institute to a novel system of dredging, which, it seems to me, may prove applicable, not only to river and harbor improvements, but also to certain varieties at least of alluvial and diluvial gold mining; that is, river-mining, barmining, coast-mining, and any other similar operations now carried on by means of coffer-dams or dredging machines. The simple and effective method to which I refer is the invention of General Roy Stone, formerly an officer of volunteers, and at present a civil engineer, engaged under General Newton, of the United States Engineer Corps, upon the government works in New York harbor. General Stone has been, since September, 1878, in charge of operations upon Diamond Reef. This reef, lying between Governor's Island and the Battery, is one of the most dangerous in the harbor. Its position in the highway of navigation, and the fact that it is dangerous only to vessels of considerable draught and at certain stages of the tide, combine to increase the serious nature of the disasters which it has caused. The reef consists partly of rock in place, and partly of deposits of glacial clay, boulders, and pebbles, over all of which lies, or did lie until it was removed, the ordinary silt and rubbish of the harbor. As the purpose of the present paper has nothing to do with the special dimensions and other circumstances of this particular work, I describe those features only which are connected with General Stone's ingenious device. Various attempts have been made to remove the upper portion of Diamond Reef and secure a navigable depth at low tide. Some years ago Maillefert undertook to accomplish this by firing charges of high explosives, simply laid upon the surface. He accomplished some good in the removal of projecting points and ridges ; but as soon as the surface of the reef had become approximately level, his method was no longer effective. After the work had been taken up by the Engineer Corps, the well-known drilling-scow invented by General Newton was brought into action ; and, so long as holes could be bored and fired in solid rock, this process was effective enough. In the mixture of hard-pan

Jan 1, 1880

By J. A. Herrick Nashua

IN this country steel made in a Siemens furnace or Bessemer converter, is generally tapped into a ladle or shoe, and then drawn through an aperture in its base into the various moulds. In order to regulate the flow of the molten mass a refractory valve is arranged at the aperture. A plumbago nozzle is fixed firmly in this aperture, and a stopper of like material is fitted to it, making a socket valve. In order to raise and depress this stopper at will, a rod is fastened-to it, extending through, the metal and over the brim of the ladle, where it is bent back in a half circle and secured in a slide. This slide plays vertically in a frame, permanently fastened to the outside of the ladle, and is moved by a lever having as a fulcrum a pin fixed in this frame, one end, of the lever being temporarily fixed to the slide, and the other end being moved by hand. Reference being had to the drawing (see Plate 1, Fig. 1), E is the nozzle, D is the stopper, A is the rod, protected as hereinafter described, C is the cast-iron framework, B is the wrought-iron slide, B' is the offset into which the rod, A, enters, and is secured in the usual manner by a key, a. Section J, K, shows the manner of hanging the lever. J is a pin attached to the slide by which the end of the lever raises the slide, B. J is the fulcrum fastened to the frame, C. K (Fig. 1) is a hand-nut fastening the slide, B, to the frame, C, at will. Fig. 2 is a side elevation of ladle, showing the outside working of the parts above described. It is the common practice to protect the rod, A, by a coating of clay and fire-sand, kneaded to the right consistency and applied to the rod, and then thoroughly dried. Just before casting, the plumbago stopper, D, is heated at its extremity to redness separate from the ladle and, at the moment of pouring, is placed in the ladle and slide, and adjusted as well as practicable. Some very serious defects ensue, causing much trouble and vexation as well as actual loss. The fire-clay coating in drying becomes cracked and seamy, and at its best is more or less loose on the rod. The hot metal sometimes cuts

Jan 1, 1879

By Clarence Zener

The internal friction of nonferrous metals vibrating at low stress amplitudes has so far always been successfully interpreted in terms of inhomogeneities of one sort or another. Examples are the fluctuation of stress across a specimen vibrating transversely,1,2,3 the stress inhomogeneities due to the elastic anisotropy and partial random orientation of the individual crystallites, localized weak regions introduced by cold-working,6'7 grain boundaries and possibly twinning planes.8'9 Perfect single crystals are, by definition, homogeneous. Actual single crystals usually, perhaps always, contains some imperfections. The present investigation was undertaken to determine whether the internal friction of single crystals may likewise be attributed to inhomogeneities. This study was made possible through the gift of a large single crystal of 70-30 alpha brass by H. L. Burghoff, of the Chase Brass and Copper Co. The specimen, 3.i in. in diameter and 10 in. long, was similar to samples previously described by Mr. Burghoff. Experimental Method The experimental method used has previously been described in institute papers.5'6'9 The measure of internal friction adopted here, I/Q, is X the logarithmic decre- ment, a measure used by some writers, and is also X the specific damping capacity, a measure used by other writers. In all measurements the stress level was kept so low that the measurements were independent of stress level. In all measurements in which the temperature was varied, observations were made as the specimen slowly cooled from its highest temperature. The specimen was vibrated transversely. Observations were made at the fundamental frequency and at the first overtone, of about 620 and 1710 cycles per second, respectively. No attempt was made to avoid acoustical losses. Experimental Results The specimen was annealed for several hours at 450°C. The temperature dependence of the internal friction was then determined from room temperature to 400°C. As shown in Fig. I, the internal friction increased by only a factor of 2 from room temperature to 300°C., then by a factor of 100 during the next Ioo° interval. These measurements are consistent with the view that the observed internal friction is the superposition of two distinct parts. One, dominant at room temperature, is nearly independent of temperature. This part may be accounted for by acoustical losses and by transverse thermal currents. It was not further investigated. The second part, when plotted in the manner of Fig. I, lies upon a straight line. Therefore it has a heat of activation H; i.e., it varies with temperature as Internal friction e-H/RT [I]

Jan 1, 1943

By E. B. Swanson

Frequent reference has been made to the increased domestic gasoline demand recorded for 1931. This increase was in the neighborhood of 7,000,000 bbl. Although smaller relatively than that to which the oil industry had become accustomed by virtue of the experience of preceding years, the increase was of substantial amount, particularly at a time when any increase at all could be regarded with eminent satisfaction. Less has been said, however, of the 18,000,000 bbl. decline in gasoline shipments to territories and foreign countries. When the loss of business outside the United States is combined with the domestic increase, there results a net loss of some 11,000,000 bbl. in total gasoline demand. The gain of 2 per cent in domestic sales gives way to a loss of 2.5 per cent in total domestic and foreign sales. The United States actually has been losing ground in the international gasoline market since 1924, when shipments from this country equaled 72 per cent of the gasoline shipments from the leading gasoline-producing countries of the world. A loss in relative standing was recorded with each succeeding year. As long, however, as gasoline shipments showed an actual increase, the loss in relative standing was of little concern. Foreign producing centers annually supplied an increasing share of the foreign gasoline markets, but, until the past year, the demand abroad continued to increase at a pace which could accommodate all of the increased output of foreign plants and yet require increasing quantities from the United States. It was not until 1931 that the various factors were combined so as to produce an actual and substantial decrease in the foreign demand for United States gasoline. Consumption in foreign countries generally declined, while the output of foreign refineries and the foreign manufacture of substitute fuels continued to increase. From our own viewpoint, this meant a loss of some 18,000,000 bbl. of gasoline business in foreign countries, one-half of it probably due to the lowering in foreign demand and the other half to the increased output of foreign refineries and the increased utilization of substitute fuels.

Jan 1, 1932

By Charles A. Kumke

THE "slot" system of mining in use at the Golden Queen mine, Mojave, Calif., does not involve any new mining methods. It is, however, a new combination and adaptation of several stoping systems in common practice. The first plans for stoping operations at the Golden Queen mine called for ordinary shrinkage stopes. The hanging wall of the vein, where exposed, is a very hard felsite with a dip varying from 50º to 70º. The vein itself is quartz, shattered and fractured enough to make it easy to drill and blast to a clean hanging wall. There is no well defined footwall. The footwall limits had to be determined by assays as the metal content faded out into the felsite. Two shrinkage stopes, each approximately 200 ft. long, were laid out and started on the 200-ft. level. One of these stopes, varying in width from 8 to 18 ft., was carried on up to the top limits of the ore, approximately 120 ft., without a break in the operation. The shrinkage system proved entirely satisfactory and low costs resulted from this operation. In the final drawing of this stope, two timbermen followed down on the ore, scaling the hanging wall clean of small fragments and placing an occasional long stull from foot to hanging wall where it was deemed necessary. Few such stulls, however, were required. The hanging wall stood up very well until the stope was entirely emptied of ore. Waste fill was then put into the stope by the glory-hole method, through a waste raise that had previously been run to surface from the middle of the stope. The second shrinkage stope ran into difficulties about 35 ft. above the sill floor. Up to this point the maximum width of the ore had been about 15 ft. The ore suddenly widened into the footwall to a distance of 40 ft. in the north end of the stope. In extending the stoping operations over this width, it was soon found that the vein material would not arch and support itself. Drilling in this end of the stope was then entirely too hazardous, and all operations were stopped. The ore was drawn through the chutes below as rapidly as possible and as soon as the stope was entirely

Jan 1, 1937

By David B. Reger

Widespread wildcatting for new supplies of natural gas and the beginning of importation from the southwest characterized the petroleum industry of West Virginia during 1944. Within the state, drilling for oil did not increase but. more gas wells were completed than in any previous year since 1937. Out of 40 wildcats drilled there were 25 gas discoveries and 15 dry holes. No commercial oil was found in the 40 wells. The proved limits of several oil pools were slightly extended by marginal drilling, resulting in 1300 acres of new oil territory, although no distinctly new pools were found. At least four new gas pools were assuredly discovered and various successful wildcats indicate future pools or wide extensions. The new proved gas territory, in definite new pools and definite extensions, is about 34,000 acres. A considerable net decline of proved oil has occarred and probably a slight decline of proved gas reserves. The account of operations, as gathered from trade journals and other reporting services, shows that 918 new wells were drilled, resulting in 71 oil wells with 613 bbl. of daily new production; 577 gas wells with 305,372,000 cu. ft. of daily open flow, and 142 dry holes. Also, 107 old wells were drilled to deeper sands, with 22 bbl. and 12,327,000 cu. ft. of added production. On the new wells the oil average was 8.6 bbl. per well per day, and the gas average was 529,241 CU. ft. per well per day. On new wells the ratio of dry holes to completions was 15.47 per cent. On deeper drilling the ratio of failures was 19.63 per cent. Production of oil for the year was estimated by the Oil Weekly as 3,069,000 bbl., as compared with 3,349,000 bbl. in 1943. Production of natural gas for the year is estimated by the author as 200,000, 000,000 cu. ft., as compared with the U. S. Bureau of Mines final figures of 223,789,000,000 cu. ft.t in 1943.

Jan 1, 1945

By F. E. Bash

A GREAT many industrial operations require the application of heat to carry on or complete processes, in which cases the temperatures must often be controlled within very narrow limits. For the lower temperatures, this control is not, as a rule, difficult as a number of types of reliable pyrometers are available for the work; for example, the mercury and resistance thermometers and the thermocouple. For temperatures above a red heat, thermocouples, platinum resistance thermometers, and total radiation and optical pyrometers may be used, depending on conditions. It is often undesirable, and sometimes impossible, to take temperatures of material by immersing the pyrometer in it or by placing the temperature-measuring device in a position in which it will attain the temperature of the material. The pyrometer may contaminate the product; the temperature may be so high that the pyrometer will not hold its calibration, clue to ineffectual protection and consequent contamination; the object may be inaccessible, as a lamp filament, etc. In such cases, a total radiation or optical pyrometer must be used. The disappearing-filament, or Morse, type of optical pyrometer works on the following principle: An objective lens, Fig. 1, focuses the image of the object whose temperature is desired in the plane of the lamp filament at F, which is at the principal focus of the ocular lens shown in the eye-piece. By this arrangement the eye will not have to accommodate itself first to the lamp filament and then to the object at a distance, and the lamp filament will appear superposed on the object. To balance the instrument, the current is adjusted by means of a rheostat until the tip of the lamp filament just disappears against the object as a background. Figs. 2, 3, and 4 show the appearance of the filament when too cold, too bright, and just balanced.

Jan 8, 1919

By T. S. Lovering

An economic geologist is concerned primarily with finding deposits of economic value, estimating their tenor and quantity, their shape and position. Thus the primary problems can largely be lumped under three headings: position, character and quantity; and all three are phases of the broader problem of genesis. Distribution, tenor and quantity are of immediate practical importance and are studied constantly by all who exploit mineral deposits. Although the emphasis changes from year to year, the problems of genesis seem more remote and rarely get the serious consideration from the field man that the other three do. Our understanding of the problems of the genesis of mineral deposits has come largely as a by-product of more evidently utilitarian work in the past, and probably will continue to grow in the same manner lor many years to come. However, it might be economically fruitful for the producers to have many competent investigators spending their time chiefly on the problems of genesis of mineral deposits. Many years ago, when first engaged in work for the United States Geological Survey in Colorado, I expressed a conviction which was just then dawning on me by saying that economic geology was turning out to be 80 per cent structural geology, to which Mr. B. S. Butler replied, "Yes, and more than 80 per cent of structural geology is lithology." At the present time there seems to be a widespread feeling among economic geologists that the problems of position or distribution are largely problems of structure and rock types. Types of Research Ptesearch in any branch of geology can be conveniently divided into two types: field research and laboratory research. Ideas are usually dug up in the field, pruned or developed in the laboratory, and taken back to the field for proving. For either the first or last step the field data should he as complete as possible, and the structural geology of nearly all our mineral deposits still needs more detailed delineation. In general, this means mapping on larger seales. Ideally the structural map should give a factual picture of a11 visible effects of stress; there is still room for vast improvement in the technique of presentation. Information that is much

Jan 1, 1940

By C. M. Wayman, M. A. Gedwill, C. J. Altstetter

Cobalt Whiskers were grown by the hydrogen reduction of CoBr,. The fcc = hcp martensitic trans-formation in these whiskers was studied using X-ray and metallographic techniques. Present theories of the fee + hcp martensitic transformation were ex-amined in the light of the present findings Experimental evidence for slip as a part of the transformation mechanism is presented. In the bulk form cobalt is known to undergo a martensitic transformation1 from an hcp to an fcc structure upon heating above about 430°C. Upon cooling, the reverse transformation starts at about 400°C, but does not go to completion except in single crystalline or coarse-grained samples, or upon plastic deformation. The transformation may be thought of as the shearing of close-packed atomic planes in such a way as to change the stacking sequence from ABCABC to ABABAB with a contraction normal to the shearing planes and an expansion in the planes,2 producing a c/a ratio slightly less than ideal. This restacking to give {0001) and (112) 11 (1010) can be accomplished by the passage of a shockfey partial dislocation over every other (111)f plane resulting in a theoretical shear of 19.47 deg. To date there has been no completely satisfactory explanation of how the partial dislocations are produced on the close-packed planes or propagated from plane to plane to give the correct stacking sequence. The object of the present research was to study some of the characteristics of the fcc to hcp transformation in geometrically simple single crystals. It was felt that whiskers of cobalt grown by halide reduction would be ideal specimens with which to study the transformation, because whiskers have the following desirable features: 1) are easily grown as fcc single crystals; 2) exhibit relatively simple geometries; 3) have comparatively low dislocation densities;

Jan 1, 1964

By R. Janes, F. Everard

Pilot plant studies have been conducted on a variety of iron ores of differing composition and grain size to test their amenability to dry autogeneous grinding and dry magnetic concentration. A general description of the pilot plant and its equipment is given with particular reference to the Aerofall mill and the dry magnetic separators developed by the Ontario Research Foundation. Test results are reviewed in detail with emphasis on power consumption, mill speed, the use of ball charges, types of ores, moisture content, separator speeds, and design. In 1957 the Ontario Research Foundation installed a pilot plant (Fig. 1) for the study of dry autogenous grinding and dry magnetic concentration of iron ores. A 61/2-ft Aerofall mill was installed as the dry autogenous crushing and grinding medium. The Cavanagh fast drum and the Double Helix, two dry magnetic separators developed at Ontario Research Foundation, were also installed. Iron ore samples of 10 to 150 tons have been investigated. These ores varied widely in mineralogy and grain size. Taconite (-325 mesh), fine-grained magnetite (200 to 325 mesh), and medium-grained magnetites (65 to 150 mesh) have been treated with varying degrees of success. Lately, considerable research has also been conducted on the metamorphosed magnetite-hematite complexes of the Labrador Trough. Operational and metallurgical data have been compiled from these tests. The effects of ore type, air flow, mill speed, and ball charge on mill operation are discussed. Metallurgical data are also presented to illustrate the operation of the dry magnetic separators. PILOT PLANT DESCRIPTION Fig. 2 depicts the normal flowsheet used. Minus 6-in. ore from a vibrating feeder is fed to the 6%-ft Aerofall mill powered by a 50-hp 550-v induction motor. The main blower, a 25-hp 550-v fan rated at 7000 cfm, draws air through the mill. Finely ground ore is conveyed by the air stream to a horizontal classifier, where expansion and a change in direction cause the +I50 mesh fraction to fall onto a vibrating

Jan 1, 1962

By Pope Yeatman

THE Committee on the Elimination of Waste in Industry, of the Federated American Engineering Societies, in its report says that "Waste in -industry is attributable to four causes: 1. Low production, caused by faulty management, of materials, plant, equipment, and men; 2. Interrupted production caused by idle materials, idle plants, and idle equipment; 3. Restricted production intentionally caused by ,owners, managers, or labor; 4. Lost production caused by ill-health, physical defects and industrial accidents. The committee sent out elaborate questionnaires, and in them divided the responsibility into Manage-ment, Labor, and Outside Contracts. These question-naires showed that in the different industries examined the responsibility of Management was from 50 to 80 per cent. and of Labor from 9 to 28 per cent. The percentage of responsibility that Management was held accountable for was much larger than any of us supposed. However, when this question is studied, we realize how necessary it is to select, in the first instance, suitable personnel, in the form of directors, managers, heads of departments, experts, etc. We would like to -believe that the percentage of responsibility of Management for waste in the mining business was less than that quoted above, but there are so many mining properties started up and operated by men of no experience in such lines, and there have been so many improvements in late years in mining and metallurgical methods not taken advantage of, that we can not believe that. the percentage will vary much from that already quoted. Quoting from a report approved by the Committee on Management of the American Society of Mechanical Engineers: Management is the art and science of preparing, organizing, and directing human effort applied to control the forces and util-ize the materials of nature for the benefit of man.

Jan 3, 1922

By R. L. Powell, E. C. Houston, V. J. Jones

The phosphate ores mined in middle Tennessee typically consist of granular rock phosphate particles disseminated in a clayey matrix. In the TVA plant near Columbia, Tenn., the phosphate ore is mined, made into a slurry with the addition of a small amount of sodium hydroxide as dispersant, and treated in a hydroseparator to remove minus 10 micron material. The hydro-separator underflow, comprising a rough concentrate, is transported by pipeline to the plant; the hydro-separator overflow, comprising a tailing, is flocculated by addition of calcium sulphate and is discharged to settling ponds at a rate of about 1400 gpm. Sedimentation in the ponds produces a clarified efluent, which may be recycled for use as process water or discharged to surface drainage. This method of tailing treatment is not entirely satisfactory since poor sedimentation characteristics of the tailing result in poor ultimate utilization of pond storage volume. The sediment contains about 70 pct water, even after several years of settling, and is not sufficiently dry to permit it to be used as back-fill, which would provide a method for reclaiming ponds that had been filled with sediment. Since important advantages would result from a process whereby the water content of the tailing solids would be made substantially lower than that obtained in the present process, several possibilities of achiev- ing this were considered. Flocculation tests were made with a wide variety of chemicals, but none gave any improvement over the results obtained with calcium sulphate. Filtering or centrifuging was found to be infeasible. Small-scale tests of dewatering by electrophoresis showed promising results, so this method was studied further in pilot-plant equipment. It was found that the tailing could be dewatered by electrophoresis to produce the solids in a form suitable for use as back-fill. However, the de-watered tailing has no monetary value at present, and the process is not economically competitive with settling pond operation under present conditions. This paper describes the pilot-plant work on electrical dewatering. It is believed that the data may find application in dewatering physically similar but economically valuable materials such as clays or mill slimes, or in dewatering phosphate tailing in the event of increased settling pond costs

Jan 1, 1950

By Benjamin C. Craft, Frank Perkins

The wall-building properties of salt-water muds can be maintained at high temperatures by additions of gum karaya, gum ghatti, gelatinized starch, or commercially prepared starch. A germicide should be used to prevent fermentation. Introduction The behavior of drilling mud has received special attention from the petroleum industry within the past few years in numerous research projects dealing with such subjects as chemical treatment, gelation, and filtration characteristics. The importance and control of filtration, or water loss, is readily apparent* It affects the analysis of side-wall cores and interpretation of electric logs; it controls to a large extent the work of primary cementing, reduces the amount of expensive fishing, and permits the running of long strings of casing. It has been found that among the many factors that have an adverse effect on filtration, the presence of electrolytes, in general, and of salt, in particular, is outstanding. The effect is one of flocculation of the colloids due to neutralization of the negative charges on the clay particles. This reaction is further increased on the Gulf Coast because high temperatures reduce dispersion, to a minimum, causing increased flocculation in both fresh-water and saltwater muds. The problem of reducing water loss in salt-water muds by the addition of gums and starch at atmospheric temperature has been investigated,' and many successful field tests in West Texas indicate its solution. From the work of Byck2 it is concluded that no existing method will permit an approximate determination of the filtration rate at high temperatures from data taken at room temperatures. Filtration should be measured at the ternperature actually anticipated in the well, or at least at a number of lower temperatures and extrapolated over a small range. A laboratory study has been made of the chemicals available for the filtration characteristics of salt-water muds at high temperatures, and the use of germicides to prevent fermentation. Laboratory Investigations Procedure Since the purpose of this investigation was to compare several different gums and starches at elevated temperatures, mud from the same source was used for all the tests. Viscosity was measured in a Stormer viscosimeter at 600 r.p.m. and water loss was determined with a Baroid High-pressure and High-temperature Wall-building Tester3 at temperatures from 80' to 250°F. and at a pressure of 500 lb. per sq. in. for 30 minutes. The samples tested consisted of 150 grams of commercial Louisiana mud, 50

Jan 1, 1943

By R. P. Heuer

In recent years an increasing amount of research work has been done on refractory materials for use in copper-smelting furnaces. A few of the larger refractories manufacturers have erected special research laboratories which are fully equipped to study the refractory problems of the smelter. A typical laboratory of this type was described in the January, 1929, issue of Mining and Metallurgy, in an article entitled "Methods of Research Newly Applied to Refractories," by W. F. Boericke. This particular laboratory is equipped for the manufacture of full-size refractory brick. It aims to study on a fairly large scale the behavior of various refractory raw materials and the effect of improved methods of manufacture. The refractories manufacturer has at his disposal the naturally occurring refractory oxides in various degrees of purity, mixed or combined with other oxides. In order to supply the copper smelter with a refractory brick that will permit the most economical operation of the smelting furnaces, it is necessary to have the optimum combination of a number of both physical and chemical properties in the brick. Unfortunately, nature has not provided any raw materials in which the perfect combination of these properties exists. It is, therefore, a problem for man's ingenuity to seek out the most desirable raw materials and develop methods of manufacture that give, in the resultant product, the necessary combination of properties in as full a measure as is possible. In the laboratory it is possible to carry out fairly broad experiments with this objective. It is first necessary to obtain and process the raw materials, then to manufacture them into brick and finally, to test these bricks under conditions designed to interpret or simulate in the laboratory the actual conditions in the smelting furnace. It is necessary for the research engineers to determine certain fundamental properties in the brick which may be subjected to laboratory measurements and to interpret these measurements in terms of brick performance in smelting-plant practice. Such procedure is not what might be called an exact, scientific one but it has been found that great progress can be made when these principles are applied. For example, the resistance of refractory brick to spalling and thermal change can be related to the thermal expansion of the refractory, its thermal conductivity and heat capacity and its

Jan 1, 1934

By Robert A. Stansbury

Keeping development ahead of retreat mining is a problem which occurs nearly everywhere longwall mining is used in the United States. As improved equipment technology has allowed the application of longwall mining to more difficult mining conditions, and with higher retreat rates, the problem has become more critical. Many factors determine development speed, including roof and floor conditions, mining heights, seam heights, and the number of entries. In an effort to maximize the rate of development and production from development sections, U. S. Steel's Gary District has used five entry, three entry, four entry and is planning two entry development panels at its different mines. With the introduction of various types of shield supports, it is now possible to utilize longwall mining in higher coal over 3 meters (10 feet), lower coal under one meter, in difficult roof conditions, and with soft floor. Improved shearers of 300 KW (400 HP) and more make cutting heights over 3 meters (10 feet) possible, and off pan shearers and improved Gleithobel plows make cutting less than 1 meter (40 inches) seam height possible. Longwall mining under these conditions puts an added strain on the ability to develop panels as fast as they are retreated. Poor roof conditions require a substantial amount of additional roof support to ensure that roof control in the head and tall entries will not hinder longwall retreat. The additional measures of longer bolts, resin bolts, point anchor resin bolts, roof mats, roof trusses, steel or wood cross bars, and roof grouting all place an additional burden on man power, installation time, and cost on the mining cycle. Additional roof bolting on development can cut the potential mining rate in half, and any roof falls cause significant delays to mining. Timbers and cribs can restrict ventilation and require more entries. Soft floor conditions can greatly impede development through tramming difficulties with shuttle cars and roof bolters, time required for cleaning and repairing roadways, and maintenance difficulties on equipment. High coal sometimes requires rib support to be Installed during the mining cycle, further cutting the mining rate. Mining low seams requires that roof or floor be mined in the head and tail entries as well as the track or tractor roadway entry to provide clearance of the longwall equipment. Mining this rock slows down the mining rate because of the extra material being mined and the extra wear and tear on equipment. To a large degree these conditions effecting development speed cannot be controlled.

Jan 1, 1981

By M. M. Fidlar, Ralph E. Esarey

A marked decrease in drilling during 1937 in Indiana seemed to have no undesirable effect upon the oil and gas industry. Instead, production figures for oil showed a small increase over those for the preceding year, although not so much gas was marketed as in 1936. Drilling activity was centered in proven areas, and the proportion of dry holes to the number of wells drilled decreased somewhat. During 1937, including old wells drilled to deeper horizons, 134 wells were completed in Indiana, of which 39 were oil wells, 39 gas wells, and 56 dry holes. Nearly 75 per cent of the holes were drilled in proven areas. Of the 36 wells drilled in wildcat areas, only four found commercial production. Wildcat wells were especially numerous in Vigo, Pike, Perry and Spencer Counties. Exploratory drilling activity in Vigo County resulted in part from the drilling of the discovery well in the new Prairie Creek field. In Pike County, wildcat wells were drilled in the search for new supplies of gas to meet the demand in the southwestern portion of Indiana. Drilling in both proven and wildcat areas in Perry and Spencer Counties continued to be heavy, because of the presence of shallow Missis-sippian sands and the resulting low cost of drilling and equipping. At the end of the year, 42 of the wells started in 1937 were not completed. Only a few locations were drilled in the old Trenton field, but the wells, many of them 40 years old, continued to furnish a small supply of gas for domestic consumption. Oil production in the Jay County portion of the Trenton area was nearly twice that of 1936, owing in part to a vacuum system installed on several leases. The Harrison County (Laconia) gas field is being developed northward to offset water encroaching from the south. This water in the black shale threatens to put an end to the steady production that this field has furnished for many years. During 1937, the Oaktown gas field again furnished more gas than any other field, but production in that area showed a marked decrease over the marketed gas for 1936. During the early months of the year, seven wells were completed in the Oaktown field to bring the total number of producing wells to over 40. At present, all the operators in the area are

Jan 1, 1938