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WE must begin by defining what we mean by the Copperbelt. This term is generally used to denote that region of Northern Rhodesia in which the copper mines of that territory are situated. The first published use of the term Copperbelt we have been able to trace dates back to 1905. The African World of December of that year contained an article entitled "The Great Northern Copper Belts of Rhodesia." The next reference we have traced is in 1909 in an article in the Transactions of the Geo- logical Society of South Africa. It began to be used generally in the late twenties and by 1929 was in common use to denote the region which today contains the existing large copper mines of Northern Rhodesia. The first of three accompanying maps is a very simple outline map of Africa showing where Rhodesia is within Africa, and where the Copperbelt is within Rhodesia. The second is a larger scale map of the Copperbelt itself. It will be seen that within the present Copperbelt there are six producing mines. Two of these are new and four are relatively established, having started operations between the two world wars. The Copperbelt also includes a town- ship called Ndola, which is not a mining town, but a railhead on the main line. This town has developed primarily as a result of the mining industry in the neighborhood. It describes itself as the Gateway to the Copperbelt and is shortly to become a refining center.

Jan 5, 1957

ABOUT 2 lb. of alumina (aluminum oxide) of high purity is required to produce a pound of metallic aluminum. Projected production of metallic aluminum in the United States is now seven to ten times the peacetime rate a few years ago. In the past, all the alumina for aluminum production in the United States has been obtained from bauxite. Part of the bauxite was mined in the United States--chiefly in Arkansas-and part was imported from Surinam. All of it was chemically treated in the United States to separate the greater part of the aluminum oxide from the bauxite, alkaline solutions being used, in a method known as the Bayer process. The ingredients of the bauxite other than alumina, such as the compounds of iron titanium, and silicon, constitute the tailings from the Bayer-process operation. This product contains sufficient iron to give it a red color and hence it is called "red mud." Lime and soda used in the processing, are also present. Varying amounts of alumina remain in the red mud, depending upon the characteristics of the bauxite, the effectiveness of the treatment, and in particular upon the amount of silica originally present in the bauxite. High-silica bauxites result in high alumina loss in the red mud.

Jan 1, 1942

NORTH AMERICA Number Members Alaska 31 Canada 333 Mexico 186 Newfoundland 2 United States Alabama 60 Arizona 171 Arkansas 10 California 769 Colorado 196 Connecticut 106 Delaware 21 District of Columbia 139 Florida 17 Georgia 6 Idaho 72 Illinois 260 Indiana 63 Iowa 10 Kansas 33 Kentucky 38

Jan 1, 1932

By W. H. Smith

IN the course of an investigation on chromium containing minor amounts of alloying elements, the information herein has been obtained on the crys-tallographic orientations resulting from arc melting, rolling, and annealing. The chromium used in this investigation was electrolytic flake obtained from the Electro Metallurgical Co. This material was heated for 20 hr at 1600°C in hydrogen with a dew point of about — 100°C. The oxygen and nitrogen content of the chromium after this treatment was 0.0003 pct 0 and 0.005 pct N. Five pounds of this chromium were arc melted in a water-cooled copper crucible. After arc melting, the oxygen and nitrogen contents were 0.002 and 0.025 pet, respectively. A section of this ingot is shown in Fig. 1. By means of a back-reflection Laue technique, the crystal habit of the cast ingot was determined. As expected, it was found that the [loo] was approximately the axis of the columnar grains. In this respect, chromium behaves like other body-centered-cubic metals in that a cubic axis is normal to the cold surface of the mold. A slab cut from this ingot was rolled at 600°C as follows: four 30 pct reductions were made with intermediate anneals at 1200°C for 15 min. Rolling was done with the [loo] of the columnar grains in the rolling direction. Following the final anneal, an 80 pct reduction was taken at 600 °C. The final sheet thickness was ten mils. By polishing and etching, the thickness was reduced to four mils and the grain orientation determined by the transmission Laue method using molybdenum radiation with a zirconium filter. Fig. 2 is the (110) pole figure for this material with the ideal (100) [011] and (111) [112] orientations indicated. The orientation is typical of most cold rolled body-centered-cubic metals having the [llO] of the grains approximately in the rolling direction and the (100) planes approximately in the plane of the rolled sheet. There is also evidence of some 10) [1 orientation. The grain orientation of sheet rolled 40 and 80 pct in the same direction as before at 600°C followed by recrystallization at 12000 C for 15 min was determined by a back-reflection Laue technique. A random texture was found in both cases. This 1200°C 15 min anneal was found to give complete recrystallization and some grain growth.

Jan 1, 1956

By H. R. Brannon, J. S. Osoba

The introduction of the scintillation counter into field use for gamma-ray well logging has provided a new tool with special utility for the deternzination of natural radioactivity of sediments. Previous subsurface gamma-ray measurements have indicated only the total amount of radioactivity of the sediments. With the scintillation counter, the relative amounts of the elements which emit gamma radiation can be determined. Sediments logged included 35 zones in wells located in the Teras Gulf Coast, East Texas, and West Teras. Although the data obtained from measurements made to date are not sufficient to evaluate the possibilities of spectral logging, it appears likely that spectral measurements will yield information of geologic value. INTRODUCTION Although variations in the natural radioactivity of sediments were recognized as early as 1909,1 the appli- cation of such variations to borehole logging was not made until almost 30 years later. A group of Russian workers in the early 1930's were successful in making crude measurements of natural gamma activity in an oil well borehole. The first practical gamma-ray logging system was developed by Howell and Frosch2 in 1939. Induced radioactivity, or neutron, logging appeared soon after the introduction of gamma-ray logging. After early work had demonstrated the potentialities of radioactivity logging, development of sensitive and stable logging equipment for field use followed, so that neutron and natural gamma logs are now run routinely and have proved to be extremely valuable in characterizing subsurface formations. Even though tremendous strides have been made in developing radioactivity logging, it is apparent that the ultimate in the method of logging has not been reached, for, until very recently1 in none of the commercially available logging systems has advantage been taken of the fact that gamma radiation is composed of a spectrum of rays, each ray having a distinct and characteristic energy. An individual gamma ray originates in a single element and has energy determined by the element. The inten- sity of radiation, or number of rays emitted from unit volume in unit time, is determined by the concentration of the element. If it were possible to sort out these gamma rays and assign them to their parent elements, thereby essentially analyzing for the elements, a wealth of new information descriptive of formation material and fluid content would be at hand. For example, if in natural gamma logging, the gammas due to potassium and to the thorium and uranium series were measured individually, data would thus be available on the concentrations of each of the three elements, adding materially to the information content of the log. In contrast, conventional gamma logs measure only a quantity proportional to the combined concentrations of uranium, thorium, and potassium. The naturally radioactive elements occur in sediments in concentrations dependent on source material of the sediment, and through their chemical characteristics, on conditions of deposition,' so that the individual concentrations may be diagnostic for particular formations. These concentrations, particularly if measured in situ, could lead to a powerful tool for correlation and for reflecting environmental conditions under which sedimentation took place. As a correlation tool, individual uranium, thorium, and potassium measurements

Jan 1, 1957

By STEPHEN L. GOODALE

THE question indicated in this title was put by letter to a number of my friends working in various industries, who have charge of young metallurgical graduates. The replies were almost unanimous in stating that the college training should cover in the most .thorough manner possible those sciences which are the fundamentals - of engineering. Mathematics, physics, mechanics, electricity, chemistry, physical chemistry, and their applications to actual problems of life were mentioned in most of the letters I received. Some writers added also business law, economics,. and finance. One reply expressed it: "These subjects, well founded, mixed with good judgment, well applied, should enable the .young man to carry on the art of life successfully." One answer stated frankly what is really wanted: "As much as possible.' ' This writer mentioned .the sciences as being very important, but he wishes men ' to be trained in metallurgy also, and he concedes the omission of some advanced chemistry and physic's to secure the metallurgy. He emphasized particularly. the a we. desirability of work in college to development' He concludes his letter with a repetition of his slogan that what is wanted is as much as is possible.

Jan 1, 1930

By R. B. Porter, R. P. Porter, R. A. Lothrop

Changes became necessary in dredging methods employed in Idaho through passage of the Dredge Mining Protective Act (1954). Among other provisions, the law requires dredge operators to construct settling ponds of sufficient capacity and character to reasonably clarify the water used in the mining process before such water is discharged into the stream. Porter Bros. Corp., a placer mining company with many years operating experience in Oregon and Montana, became interested in strategic mineral placers in Idaho in 1950 when it was learned that prospectors had discovered a radioactive mineral deposit in Bear Valley Creek, 95 miles northeast of Boise. The company acquired mining leases and proceeded with exploration and development work on the property. After extensive research had resulted in the determination of successful separation processes, contracts were negotiated with the federal government and deliveries of columbium-tantalum and uranium concentrates commenced in 1956. The mining operations are located in a primitive area of Idaho among salmon spawning grounds and crystal-clear mountain trout streams. To avoid involvement in a very controversial issue, it appeared advisable for the company to develop water treatment procedures exceeding those requirements stated in the Idaho Dredge Mining Protective Act. Operation: The company operates one 6 cu ft continuous bucketline dredge and one 4 1/4 cu ft continuous bucketline dredge on the property. The dredges are jig-equipped, with feed being screened to 3 in. by trommels. The screening and gravity concentration methods satisfactorily separate the heavy minerals from companion clays, sand, and gravel. However, this separation of the heavy minerals requires water from the dredge pond with a minimum content of silt and colloids; therefore, water for dilution is added continuously to the dredge pond to suppress solids buildup. Discharge of this highly turbid water to maintain the proper pond level would ultimately result in an excessive silt load in Bear Valley Creek. To prohibit the turbid pond water from flowing directly into Bear Valley Creek, it was necessary to isolate the dredging area. Main by-pass canals were constructed along each side of the dredge pond and numerous secondary canals were dug for diverting seepage and snow runoff. One by-pass canal, extending more than two miles along the west side of the valley, diverts the main stream as well as tributaries entering from the west; a canal east of the dredge area diverts streams entering from that direction. At the beginning of operations in 1956, the dredge pond effluent was filtered through tailings and settled by use of coagulents in a series of lagoons. The filtrate was then discharged directly into the stream. Although this procedure gave satisfactory results in conformance with the state law, ice buildup and lagoon freezing hindered the efficiency of the process during periods of low temperature. For this reason, testing began in 1956 on a water treatment process that would operate efficiently under the extreme weather conditions encountered in Bear Valley. Development of Water Treatment System: Porter Bros. Corp. established the following requirements for effective continuous treatment of dredge pond effluent to the stream which, at low flow conditions, effluent to the stream which, at low flow conditions, would not result in a turbidity exceeding 25 ppm in the stream, 2) produce a sludge sufficiently dense to minimize disposal area requirements, 3) be semi-portable to follow dredge movements, 4) be capable of operating at low temperatures, and 5) be capable of handling a variety of capacities and turbidities.

Jan 1, 1961

By D. G. F. Hedley, D. F. Coates, K. Barron

INTRODUCTION Preceding papers presented in this symposium have considered the influence of various parameters, such as geologic structure, groundwater, etc., on the stability of rock slopes and have given some analyses and guide lines for slope design. To carry out such analyses it is necessary to put numbers to these parameters; where possible, this is best done on the basis of in- situ observation and measurement. Since none of the design analyses can be considered exact and since conditions vary during excavation, it is also desirable to monitor the behaviour of the slopes as the excavation proceeds. In this manner a feedback of information on the actual excavation conditions can allow a continuous reassessment of the design parameters to be made and can give early warning of incipient failures. The purpose of instrumenting rock slopes is thus to provide information which fits into one of two categories: (a) To give basic data to assist on-site assessment and design of the rock excavation. (b) To provide data for the control and assessment of safety during excavation. The purpose of this paper is to review briefly some of the instruments and measuring techniques available for gathering this data and to indicate where such data may prove useful. This is not a comprehensive review of all available instrumentation but, rather, is a survey of some of the instruments and techniques with which the authors have had some experience and which have proven useful. STRUCTURAL ASSESSMENT Whilst most structural assessment of a site is done on the basis of geologic mapping and core examination, there exists some instrumentation which can, in particular circumstances, assist in this assessment. Seismic instruments can be used to determine the geometry of formations and to give an indication of the relative competency of rocks. These instruments operate using seismic reflection or refraction techniques and, although mainly confined to shallow sub-surface exploration, can be useful in distinguishing between soil/ bedrock contacts and, in some cases, the extent of weathered surface rock.

Jan 1, 1971

By C. H. Mathewson, J. A. Collins

The process of plastic extension of face-centered cubic single crystalline rods is so well understood, since the notable studies of Taylor and Elam,1 that the change in orientation of any crystal by slip and rotation may be predicted from the measured elongation. It is customary to assume a very homogeneous deformation, wherein gliding lamellar arc free to rotate so that their slip direction continually approaches the axis of the rod, until a second slip system comes into operation; whereupon conjugate slip proceeds quantitatively to an end adjustment with the [121] direction in the axis of the rod. This process has been checked in malty face.-centered cubie materialsand and readily permits the preparation of specimens that have been subjtvted to various determinable amounts of shearing action. It is elearly of interest to study in such measurably strained speeimens the, development of a recrystallized structure on annealing and if possilble detect the source of nuclei from which the new crystals grow. Strain-:~nneali~ig experiments of this charactcr have been performed by others but not in detail sufficient to permit a study, for example, of the number of recrystallized grains vs. the amount of shear. In the experiments now reported, this was done with a wide variety of orientations covering nearly the entire range of slip on a single system and corresponding to amounts of shear (ratio of shearing distance to distance between lamellae at the conclusion of a test of from 0.08 to 0.57. A particular point wa-made of determining the crystallite rotation, or small angular range. assumed by the octahedral slip plane after these various amounts of shear. The, mechanism of reerystallization and the magnitude and effeet of recovery on the recrystallization process was investigated.

Jan 1, 1940

By M. Gangal, B. Paul

It may be seen from Maurer's survey (Maurer,l 1966) that most of the common methods used in rock drilling today depend upon mechanical loading of the rock. In order to predict the behavior of rock under an imposed system of stresses, it is necessary to have a valid criterion which delineates those combinations of stress which cause macroscopic rock failure from those which do not. Admittedly, the conditions under which brittle materials fracture depend very much upon statistically variable local effects such as inclusions, grain boundaries, minute imperfections, etc. However, it is extremely desirable to be able to predict fracture under complex states of stress by means of a stress-criterion of failure, where, for a given material, the effects of the other variables mentioned are incorporated into a small number of experimentally observable parameters. One of the most successful of these "macroscopic stress criteria" has been the Coulomb-Mohr theory 2,3 (also see Jaeger 4 and Terzaghi 5), modified by the addition of tension cutoffs (Paul 6). At first thought it might seem rather odd that a macroscopic theory is capable of predicting fractures which originate at highly localized random imperfections at an atomic level (or more likely at the level of individual mineral grains in rocks). However, Griffith7 showed that fractures originating near the tips of randomly oriented elliptical cracks lead to the macroscopic stress criterion of failure indicated in Fig. 1 (a). Fig. I (a) is to be interpreted in the following way: P and Q represent the maxi mum and minimum principal stresses (compression is considered positive) in a macroscopically isotropic body; fracture will not occur for any combination of principal stresses lying within the 'fracture curve' shown, but

Jan 1, 1967

By J. A. Collins, C. H. Mathewson

The process of plastic extension of face-centered cubic single crystalline rods is so well understood, since the notable studies of Taylor and Elam,1 that the change in orientation of any crystal by slip and rotation may be predicted from the measured elongation. It is customary to assume a very homogeneous deformation, wherein gliding lamellar arc free to rotate so that their slip direction continually approaches the axis of the rod, until a second slip system comes into operation; whereupon conjugate slip proceeds quantitatively to an end adjustment with the [121] direction in the axis of the rod. This process has been checked in malty face.-centered cubie materialsand and readily permits the preparation of specimens that have been subjtvted to various determinable amounts of shearing action. It is elearly of interest to study in such measurably strained speeimens the, development of a recrystallized structure on annealing and if possilble detect the source of nuclei from which the new crystals grow. Strain-:~nneali~ig experiments of this charactcr have been performed by others but not in detail sufficient to permit a study, for example, of the number of recrystallized grains vs. the amount of shear. In the experiments now reported, this was done with a wide variety of orientations covering nearly the entire range of slip on a single system and corresponding to amounts of shear (ratio of shearing distance to distance between lamellae at the conclusion of a test of from 0.08 to 0.57. A particular point wa-made of determining the crystallite rotation, or small angular range. assumed by the octahedral slip plane after these various amounts of shear. The, mechanism of reerystallization and the magnitude and effeet of recovery on the recrystallization process was investigated.

Jan 1, 1940

By J. Price Wetherill

THE coal-seams that are worked vary from 32 to 100 feet in thickness, and occur at all angles of inclination, but are never flat for any great extent. They contain coal, slate, and an unsolidified coal, called dirt by the miners, in various proportions, a uniform seam of coal alone being rare. The upper walls are composed of conglomerate, sandstone, or slate; the first two hard and solid in texture, and withstanding the action of the atmosphere and moisture sufficiently well to offer but little trouble to the mining operations ; while the latter crumbles rapidly, owing, in part, to the decomposition of iron pyrites which it contains in large quantities, and in part to its own friable character, and requires constant care to avoid accidents to the men working below it, and to prevent its mixing with the coal mined. The floors are composed of slate. As in all mining operations, the. general system pursued is to reach with a permanent outlet such a point in the seam as will

Jan 1, 1877

[ ] Thomas C. Baker, Jr., has been transferred by the American Manganese Steel Div. of the American Brake Shoe Co., from their Oakland, Calif., branch to their Cleveland, Ohio, office. He will represent them in Ohio and Michigan. William H. Carson, has been appointed district manager of Goodman Mfg. Co's. Huntington, W. Va. sales office. He succeeds Morris W. Highland, granted a leave of absence for health reasons. Mr. Carson, a graduate engineer of Michigan College of Mining & Technology, has been a member of the company's Huntington sales force since 1939, the past two years as assistant district manager. James Parnell Caulfield, former general manager of the Utah Copper Div. of Kennecott Copper Corp., has been appointed assistant general manager of Kennecott's Western Mining Div. L. F. Pett, general supervisor of operations of the Utah Copper Div., was named Mr. Caulfield's successor as general manager. William D. Charles, on completion of his graduate studies at the Massachusetts Institute of Technology, accepted the position of mineral engineer with American Cyanamid Co.

Jan 1, 1952

By W. W. Gorr, R. Smith, E. H. Wyche

THE combination of high strength and corrosion resistance of cold-worked 18 Cr, 8 Ni steel has been advantageously utilized for some time, particularly in aircraft and rail car structures. There are, however, certain limitations on the use of such materials because the high strengths can be obtained only by cold-working, limiting the available products to sheets, strip, wire and tubes. The authors sought to overcome these limitations by resorting to precipitation-hardening, which has been used so successfully in nonferrous metallurgy but only to a limited extent in iron-base alloys. Accomplishment of this objective not only overcame the limitations, but also effected certain improvements in mechanical and other properties. This paper is an account of the development by Carnegie-Illinois Steel Corporation of a precipitation-hardening 18-8 stainless steel (called Stainless W? and tentatively identified as type 322). A description is given of its composition and metallurgical characteristics, heat-treatment, physical and mechanical properties and corrosion resistance. DEVELOPMENT OF THE NEW STEEL For a considerable length of time the authors were unable to determine the mechanism of the precipitation-hardening process that had been noted by Ffield 18,19 in 18-8 Ti or 18-8 Cb after cold-working and reheating to moderately elevated temperatures. All known variables were exhaustively studied, but with little success. However, results began to indicate that chemical composition was the most important variable, particularly the ratio of austenite-forming to ferrite-forming elements. The investigators 'then focused their attention upon the composition, and, in particular, upon the element titanium and its mode of alloying in the presence of other elements. A heat was obtained that could not be brought to the softness level of annealed 18-8. The response to cold-straining and aging* was very marked by previous standards, and, more important, cold-straining was found to be entirely unnecessary to produce the precipitation-hardening effect. The chemical composition of this heat was: C, 0.06 per cent; Mn, 0.54; P, 0.016; S, 0.016; Si, o.58; Ni, 7.28; Cr, 17.6o; Ti, 0.90; Al, 0.17. For some time the development work, particularly on composition, was carried

Jan 1, 1946

By D. B. Gillies

IN 1938 the Republic Steel Corp. announced that it had leased the ore mines and other property of the Witherbee Sherman Corp. at Port Henry, N. Y. The announcement brought forth an interesting reaction. Two questions were asked repeatedly: (1) Is the iron product high grade? (2) Is there a substantial reserve? The answer to both questions was and is a decided and emphatic "Yes."

Jan 1, 1943

By H. C. van Elst

Ultrahigh-speedphotographic and electronic meth-ods were applied to an investigation of details of brittle-fracture propagation in steel. The brittle fractures studied were obtained in steel plate with the aid of a Robertson apparatus. It was found that a brittle fracture proceeds by discrete steps ranging from 30 mm near the stop temperature to less than 2 mm at lower temperatures. The halting FROM prior metallographic observations of brittle fracture in steel' it could be concluded that the distribution of mechanical twins along a brittle fracture was similar to the distribution of mechanical twins induced by explosive deformation. It was therefore assumed that a running brittle fracture created stress waves, cf. Refs. 2-7. An emission of stress waves by a brittle fracture, however, seems only conceivable if the fracture propagates by discrete steps. For this reason a study of the details of times between successive steps drop in this tem-perature region from 20 usec to about 1 psec. The stepwise propagation mechanism is accompanied by an intermittent emission of stress waves of the order of 100 to 200 kg per sq mm. These stress waves seen1 to play an important role in the mechanism of brittle fracture as will be discussed. brittle-fracture propagation was undertaken to investigate the possible determination of the fracture steps and the emitted stress waves associated with the assumed mechanism. The more practical object of this work is the development of a test method for the determination of the ductile-brittle transition in small specimens. This has special advantages for the study of irradiation damage in steel. In this test method, which will be published in a following paper, the stress waves emitted by an actual brittle fracture are reproduced with explosive or electrical means and are then transmitted through small specimens at various temperatures. In the present paper only the results of the brittle-fracture study will be reported.

Jan 1, 1964

By H. A. Wheeler

. Page History.................................533 Location .........:.....................536 Geology...............................539 Description of the Eastern Field ... :..................543 Description of the Western Field .........,...........546 Quality of the Oil ................ ,........549 The Oil Sands .,.............................549 Drilling Features'........................., . 551 Well Density...........,.'...............:. 552 Plant Equipment.......................:.'., .554 Market Features..........................555 Production Prices.........,...................557 Royalties and Rentals.........................558 Cost of Oil Leases............................'.558 Operating Expenses..........................559 Operating 'Profits...........................559 Gas Developments ........................560 Gas-Gasoline production ... :....................561 Statistics.......562 History Illinois has SO recently attained the third place in the oil production of the United States that few realize its great importance, or are aware of its highly profitable character. Since 1907 Illinois has furnished about 15 per cent. of the United States output and about 10 per cent, of the world's production. The value of the output in 1913 is estimated at $307000,000, of which about $20,000,000 is profit. The present prosperity dates from 1905, but efforts have been made since 1865 to develop production and geologists have been very sanguine as to its future for over 25 years. Had the oil operators been as confident as the geologists, the field would have been opened at least 30 years earlier. For the rich Eastern Illinois oil field is located along the La Salle anticline, that was mapped 46 years ago by Professor Worthen in the

Jan 1, 1915

By AIME AIME

ELECTRICAL methods of geophysical exploration attracted major attention at the three sessions devoted to geophysics on Monday and Tuesday. At the opening' meeting Monday morning Hans Lundberg gave the paper by himself and Folke Kihlstedt; he described the use of the Racom, discussed last year, and the method whereby it is possible to eliminate all but subsurface, effects in electrical exploration. In the discussion Theodor Zuschlag pointed out some of the theoretical considerations behind the field procedure. Karl Sundberg's paper on the effect of impregnating waters was presented by title only, and S. F. Kelly then gave an abstract of a paper on the electrical properties of ores, by J. J. Jakosky, R. N. Anderson and Clyde H. Wilson. , This dealt with an exhaustive series of laboratory tests on the variation of -conductivity of ore specimens with the frequency of the energizing current, and of the effect of moisture content in typical clays and gouges on their conductivities at various frequencies. Considerable discussion was provoked during which the authors came in for some-criticism on their measuring circuits and for their assumption that a solid conductor could be compared with linear ones. They were praised, however, for making a start toward a compilation of resistivities for ores and rocks. Dr. Slichter disagreed with them that the conductivity of an orebody was primarily capacitive. He also called attention to the fact that it was high time geophysicists adopted the standard physical expression of ohm-,centimeters or ohm-meters to express resistivities. This same point was the burden of the next paper,. "Uniform Expression for Resistivity," by Sherwin F. Kelly, presented by title only.

Jan 1, 1932

By G. S. Brooks

DURING the past few years, the Mineral Point Zinc Co. has had under consideration the improvement of various types of gas-filtering apparatus used in the removal of dust from crushing and milling plants, in the manufacture of oxide, and on blast-furnace fume and sintering furnaces. The original equipment of the various plants of the company was, of course, along lines of the standard stationary bag house. These houses required large surfaces, hand shaking, and varied only in the manner of the collection of solids and in the distribution of the gas. Early in 1908, the first trial of a mechanical bag house was made at Nassau Plant at Depue, Ill. The duty of this installation was on dust-laden gas from a fine-crushing mill. The Printz and Rau bag machine was finally adopted and put into operation. This ingenious machine embodied what were then to us two novel features in bag-house practice: 1. An intermittent crinkling and snapping of the filtering fabric to free the meshes of solids. i 2. A reversal of gas flow for a short period by a temporary connection w th the suction trunk. This equipment worked fairly well except in cold weather, when we ran into condensation troubles. Had we at that time understood more fully some of the limitations of fabric filtering work, these might well have been remedied. We were impressed by this experience, however, with the efficiency of sudden tension on the fabric under suction. After a study had been made of some of the Western blast-furnace houses using the reversal-of-flow feature, experiments were started early in 1914 with a view to developing an automatic equipment along the best lines of our past experience. The objects sought were: 1. Keeping labor out of the houses for hygienic reasons. 2. Reduction of labor costs. 3. Reduction in -size of hag houses. 4. Accessibility. 5. Ability to handle relatively hot gases where required.

Jan 11, 1917

By AIME AIME

THE MILLING PROGRAM on Monday required a morning and afternoon session with a special luncheon of the Milling Committee in the Engineers Club at noon. Grinding and flotation were the main subjects of the papers which drew an attendance of fifty or more at each session. Under the direction of Chairman Arthur F. Taggart in the forenoon, all papers on flotation and general milling were considered, leaving the, after- noon free for crushing and grinding, with Dr. Galen H. Clevenger in the chair. The high spot was the first public presentation of the idea of size reduction of minerals by explosive shattering.

Jan 1, 1932