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By Gene D. Clayton, Robert R. Dimock

A time-consuming and expensive preshearing program to minimize the adverse effects of blasting on slope stability at Kennecott Copper Corp.'s Ruth Pit in east-central Nevada has been eliminated in favor of down-the-hole, nonelectric delayed blasting which can produce a smooth wall effect and improve blast fragmentation. The new blasting approach resulted from a Kennecott engineering investigation aimed at improving the stability of the extremely variable rock conditions found throughout the pit by reducing the vibrational energy imparted to the walls with conventional bench blasts.

Jan 4, 1977

By H. O. Hofman

PAGE Part I. Decomposition OF Zinc Sulphate by Heating in Air, . 811 I. Introduction............ 811 II. Zinc Sulphate Used,..814 III. Fumes and Pyrometers,........ 816 IV. Heating Zinc Sulphate—Dehydration,...... 817 V. Heating Zine Sulphate—Decomposition...818 (a.) Beginning of Decomposition..818 (b.) Rapidity of Decomposition,..819 (c.) End of Decomposition..823 (d.) Retardations in Heating.-Curve,..825 (e.) Formation of Basic Salts,..826 Part II. Decomposition OF Zinc Sulphate by Heating with Carbon (Reducing Roast), .830 I. Introduction,........... 830 II. Experiments and Results ,.........832 III. Summay,........... 834 Part 111. Formation of Zinc Sulphate by Roasting,... 834 I. Introduction,........... 834 IT. Description of Blende,......... 836 III. Outline of Operations,.........838 IV. Details of Experiments.......... 839 1. Decrepitation,.......... 839 2. IgnitionPoint,....839 3. Sulphatizing-Roast of Joplin Blende..840 4. Sdphatizing-Roast of Warren Blemde ,..843 5. Sulphatizing-Roast with Addition of Pyrite...848 6. Summary of Sulphutizng-Roasts,....... 854 Part IV. Appendix : Formation of Zinc Ferrate...856 Part I. Decomposition of Zinc Sulphate by Heating in Air. I. Introduction. With the exception of lead sulphate. all common metallic

Jan 1, 1905

By Gerhard Derge

THE orientation relationships resulting from allotropic transforma-tions and the formation of segregate structures in metals and alloys have been the subject of the eight earlier papers in this series1. A brief summary of orientation studies has also been given by Sachs2. A survey of these papers discloses that the factors that determine the orientation relationship of a precipitated phase to its parent solid solution, as Well as the outward form and appearance of the new phase, are not completely understood. It is now evident that crystallographically analogous systems, as a rule, exhibit the same type of Widmanstätten figure and orientation relations, so that useful information is not to be expected from examination of a new alloy involving lattice combinations of which the orientation relationships are already known. Therefore, the determina-tion of the relations existing between lattice types that have not already been studied seems to be the most promising mode of attack upon the problem; both of the systems reported in this paper represent new com-binations of lattice types.

Jan 1, 1937

By R. S. Dean

THE first attempt to establish an equilibrium diagram of the lead-antimony series was made by Roland-Gosselin1 in 1896. This investigation classified the system as a purely eutectiferous one, with the eutectic at 12.5 per cent. antimony and 228° C. In the next year, Stead2 placed the eutectic temperature at 247° C. The error in temperature made by Roland-Gosselin, however, has been perpetuated in the literature with a remarkable degree of persistency; this value was accepted by Campbell (1902), and Ewen (1910),3 and will be found in the last edition of Desch's3 Metallography (1922). Gonterman's investigation, made in 1907, was the most complete one available at the time the present investigation was started. He concluded' that the system was a simple eutectiferous one and placed the eutectic at 13 per cent. antimony and 247°C. Other investigations by Tammann (1907),5 Garbow (1909),6 Rudolfi (1910),7 Loebe (1911),8 and Leroux (1913)9 added little, if any-thing, to Gonterman's diagram. A number of investigations have been made of physical properties of the alloys. The electrical conductivity of the series was studied by Matthiessen (1860)10 and by A. W. Smith (1921);" the thermoforce by Rudolfi (1910),12 and Pelabon (1923);13 the specific heat by Durrer

Jan 2, 1926

Jan 1, 1881

Jan 1, 1898

The Engineers Society of Western Pennsylvania, William Penn Hotel, Pittsburgh, Pa. K. F. Treschow, Secretary Since 1880 this society has been publishing Proceedings containing papers on a wide variety of engineering and related subjects The Proceedings are issued monthly throughout the year (except for the months of August and September each year) and the monthly Proceedings from February of one year to and including January of the next are also collected in volumes The latest is vol 47, for 1931 The rate of subscription for the monthly Proceedings is $5 per year throughout the Postal Union, single copies (monthly), 50 cents each The price of the yearly volumes from vol 17 to date is $5 each, unbound. The Secretary will quote prices for

Jan 1, 1933

Schedule of Events

Jan 1, 1977

By H. Ries

Introduction BODIES of pyritic ore in schistose rocks have long been known in different parts of the world. The several occurrences resemble each other in being usually of more or less lenticular shape, inclosed in walls of schist or gneiss, and carrying pyrite, chalcopyrite, and pyrrhotite in varying proportions, as the chief ore minerals. The deposits differ, however, in that sometimes one, sometimes another, of the three sulphides mentioned may predominate. The orebodies in general are more or less closely conformable with the schistosity of the wall rocks, although in cases this may not hold true. The boundaries may or may not be sharp, but in general are fairly distinct. The lenses vary in size, may occur singly, or in groups; in the latter case they may be in line, overlapping, or occasionally parallel. Pinching and swelling of individual lenses is not uncommon. The genesis of these pyritic bodies has provoked much discussion, and they have been variously classed as sedimentary, igneous intrusions, hydrothermal replacements or impregnations, etc. Indeed, in some cases different geologists have most positively assigned widely diverse origins to the same deposit, as in the case of Rio Tinto 1 and Rammelsberg.2 It is true that in the light of modern criteria, we have been able in a few cases to decipher clearly the process of origin and so there seems no doubt now regarding the genesis of the deposits at Rio Tinto, Spain;3 Rammelsberg, Germany ;4 Ducktown, Tenn.;5 southwestern Virginia;6

Jan 8, 1917

We would like to thank Mr. Mandolesi for his informative paper on rails from strand cast steel. The chemical and structural properties of the strand cast steel were of particular interest to us. We would like to supplement his excellent report with some of Inland's findings from our Caster with submerged nozzles and strands reduced in line from 7" x 7" to 5-5/8" square cross section. Inland has conducted extensive segregation studies on AISI 1049 steel - Fine Grain 0.50% carbon and 0.75% manganese. Based on approximately 80 heats, our normal segregation pattern results in analyses of .49% carbon in the center, and 0.50% carbon at the midway and edge position. The sulfur analysis averages .025% in the center, .027% midway, and .026% at the edge. Note the slight negative segregation between the center and midway position. This steel, being lower carbon and probably cast nearer the liquidus, resulted in less segregation than the 0.80% carbon rail steel.

Jan 1, 1972

By E. T. Dumble

THE first specimens of this material which came under my notice, as found in the State of Texas, were sent to me by Mr. J. C. Melcher, of Fayette county, soon after the organization of the State Geological Survey. I wrote him concerning it, and had the locality and manner of occurrence described, but 1 had no opportunity to visit and examine the deposit until the present field-season. Later, specimens were collected by Dr. Penrose and myself on a trip made by boat down the Rio Grande, from Eagle Pass to Hidalgo, in June, 1889. At the time of collection I marked the substance "Albertite," doubtfully, but, on examination, it proved to be nearer Grahamite. The geological horizon of the two occurrences is Tertiary. The first locality mentioned is in the upper part of the beds called by us Fayette beds, and provisionally correlated with the Miocene, or Grand Gulf of Hilgard's Mississippi section, while the latter is in the lowest strata of the Eocene which are exposed on the Rio

Jan 1, 1893

Jan 1, 1961

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Jan 1, 1938

By J. Murray Riddell, George A. Morrison

THIS paper is a companion to the one by George A. Morrison on Mining a Deep Limestone Mine in Ohio.[+] Barberton is 8 miles west of Akron, Ohio, and 23 miles south of Cleveland. The underground mining of limestone at Barberton constitutes the world's deepest limestone mine. The stratigraphy is as follows: 0-20 ft. Loam, clay, sand and gravel. Water bearing. 20-40 ft. Fractured. sandstone. Water bearing. 40-110 ft. Sandstone with interbedded shale, slightly fractured. Water bearing. 110-314 ft. Sandstone with interbedded shale, slightly fractured. Water carrying. 314-2197 ft. Shale with occasional seams of sandstone, which varies in thickness from a few inches to 4 feet. Dry. 2197-2247 ft. Limestone. Dry. 2247-2742 ft. Dolomitic limestone. Dry. 2742-2767 ft. Salt. Dry. 2767- Dolomitic limestone. Dry. All of the strata dip to the southeast, about 0.5 per cent from the horizontal. The top 110 ft. of the crust is water-bearing. The rock strata are naturally fractured to a depth of 314 ft., sufficient to allow the passage of water. In the shaft-sinking operations, a stra was encountered at a depth of 520 ft., and flows of methane gas were pierced at depths of 1350 and 1952 feet. Specifications for the mine plant called for, in part, the sinking of two vertical shafts and a hoisting plant capable of producing at the rate of 300 tons per hour. No. I shaft is 550 ft. west of No. 2 shaft. Each shaft measures 8 by 17 ft. outside of steel. General features of the design (Fig. I) are: Principal set members, 6-in. H-section; connecting angles (studdles), 3/8 by 4 by 4-in. angle irons; spacing of sets, 8 ft. centers; spacing of bearer sets, generally, 160 ft.; bearers, of 12-in. I-beams. Each bearing set featured a concrete ring about the periphery of the shaft, steel to rock, and 8 ft. in height; permanent guides, 6 by 10-in. long-leaf yellow pine, 85 per cent heart. THE SHAFT-SINKING OPERATION The preliminary shaft-sinking work consisted of driving interlocked steel piling about the exterior of the shafts to depths of 35 and 32 ft., respectively, and of such horizontal dimensions as to ultimately permit the pouring of a concrete collar 2 ft. in horizontal thickness. Following the pouring of a shaft collar, a temporary wooden headframe for shaft-sinking purposes was erected. The head-frame, while ordinary, featured: (I) a storage pocket of 300 cu. ft. capacity with truck servicing facilities, and (2) pneumatically operated dump doors, which were actuated by the hoistman, thus caring for the dumping of the "ball-and-chain"

Jan 1, 1944

By B. Das, V. Hucka

In light of the present energy crisis, coal appears now as the only reliable source of energy. The production of coal is expected to regain a rising trend after the latest slump. Aside from the competitive price with natural gas and oil, the other retarder of coal production is its environmental pollution effect. Gasification of coal has been advanced as the partial solution to the energy-ecology crisis. All the Advantages In situ gasification of coal may be considered a further step in this direction. It carries all the advantages of normal coal gasification as a stable source of energy; it is clean to handle and nonpolluting of the environment. It partially and sometimes fully does away with mining, makes uneconomical low grade coal and lignites economical and places some formerly unworkable seams within the scope of modern technology. The seams posing problems for mining due to tectonic disturbances may be converted into gas in situ. Low grade coals, such as lignites, which otherwise would be left in nature as uneconomic wealth, may be exploited by underground or in situ gasification. Thus, in situ gasification is likely to increase the exploitable reserves of coal and may reduce the cost of production. An additional merit of this method is that coal substance never reaches the surface and there is no problem of cinder disposal.

Jan 8, 1973

By O. D. A. Pease, C. D. Young, C. H. Strand

In an effort to employ cast steel of a stronger structure than that found in the annealed steel casting, the possibilities of heat treatment which will increase the strength without materially decreasing the ductulity may be resorted to.

Jan 1, 1915

GENERAL COMMITTEE GERALD F. G. SHERMAN, Chairman. ARTHUR NOTMAN, Secretary. NORMAN CARMICHAEL, JOHN C. GREENWAY, W. L. CLARK, W. G. McBRIDE, B. BRITTON GOTTSBERGER, FOREST RUTHERFORD. General Committee on Transportation WALTER DOUGLAS, Chairman. CLEVELAND E. DODGE, Secretary. ARTHUR S. DWIGHT, JOHN C. GREENWAY, JULIUS KRUTTSCHNITT, JR. Committee at El Paso W. D. GORDON, ROBERT McCART, JR., W. W. ROSE. Committee at Santa Rita JOHN M. SULLY, Chairman.

Jan 12, 1916

By M. C. Chang, J. Dasher

The Crucible mine in Pennsylvania, operating on Pittsburgh seam coal, is rated at 5000 tpd. The washing plant, built in 1943, is rated at about 400 tph, using hydroseparator boxes to wash the coarse coal (4 x 5/16 in.) and hydrotator units for the fine coal (5/16 x 0). It is generally acknowledged that gravity concentration equipment cannot be used efficiently to bene-ficiate coal finer than about 65 mesh. Before the present flotation circuit was installed, Crucible recovered its fine coal slurry, predominantly —24 mesh material, by passing it through a battery of five 14-in. and one hundred and ten 3-in. Hey1 & Patterson cyclones in parallel with a 75-ft Dorr thickener. About two thirds went to the cyclones and one third to the thickener. Underflows from cyclones and thickener were filtered, respectively, in one 12-disk Eimco and two 4-disk Oliver filters fitted with stainless steel cloth. The resulting cakes were added to the coarse metallurgical coal. The filtrates, overflow from the 3-in. cyclones, and thickener overflow were recycled to the coarse coal plant. The three major problems encountered in this system became acute when the mine switched from track-mounted machinery to the more economical off-track equipment. The quality and uniformity of product declined, too much slime accumulated in the circuit, and waste pond disposal became highly impracticable. Lowering of Quality and Uniformity: Since the filter cake was not beneficiated in any way, addition of this material, which contained about 18 pct ash. would certainly lower the quality of metallurgical coal. Difficulties of handling the high-ash, high-moisture cake were compounded by the lack of adequate blending facilities at the mine, making it impossible to maintain uniform feed for the coke ovens. For a two-month test period, to verify the source of trouble, all filter cake was excluded from the metallurgical coal. The excluded filter cake was stocked in the yard. Slime Buildup: The moisture retained in the coarse coal products and the filter cake provided daily the only means of slime bleed from the circuit. As this bleed was not enough to offset the incoming fines in the raw coal feed, there was excessive buildup of slimes. To operate at all, it was necessary to purge the system each weekend by pumping all the solids from the thickener to a waste pond. The slimes built up during the week progressively increased the apparent viscosity and density of the circulating plant water, so that hydroseparators and hydrotator units had to be constantly adjusted. Uniformity, yield, and quality of the metallurgical coal suffered in consequence, and the filter cake ash and moisture contents increased from Monday to Friday. Limited Waste Disposal: Location of the plant does not permit unlimited waste pond area. Maintenance of a waste pond for the purpose of emptying the thickener during weekends became a costly burden that could not be tolerated. HOW THE PROBLEMS WERE SOLVED The flowsheet (Fig. 1) chosen to overcome these difficulties is considered the one most economical to install and operate. In a preliminary change made before the flotation circuit was installed, the cyclones and thickener were first operated in series, the overflow from the 3-in. cyclones, after flocculation, being discharged into the thickener and the thick-

Jan 1, 1960

By T. E. Eagan, W. R. McCrackin

IN dealing with segregation in babbitt, and its effect on the final cast structure, which is a bearing, it is obviously impossible to cover all of the compositions manufactured. Each composition, of course, will exhibit certain specific types of segregation. However, as examples,, two compositions of babbitt are presented: one a tin-base of well-known analysis and the other a lead-base, which in the past few years has found wide usage. Bearings usually are cast either statically or centrifugally; therefore the effect of these two methods on segregation is presented. EXPERIMENTAL PROCEDURE A slab of babbitt 1/2 in. thick by 5 in. wide and 17 in. long was cast, using a book mold with the long edge vertical. An A.S.T.M. grade 2 babbitt was used (3.5 per cent copper, 7.5 per cent antimony, remainder tin), to which 0.10 per cent tellurium had been added. Unfortunately, no metal without tellurium was available. The mold to hold the babbitt was heated to approximately 300°F., the temperature being judged by the babbitter. The pouring temperature of the babbitt was 875°F. (470°C.). One slab was made by allowing the babbitt to cool without stirring. The other slab was stirred during the entire cooling cycle. This stirring consisted of a vigorous churning or puddling into the mold until complete solidification had taken place. Three samples were removed from these slabs. One was taken at the extreme bottom, another half way to the top, and another at the extreme top, all at the center of the width. Chemical, macroscopic and microscopic examination was made of all samples. Table I shows the chemical analyses obtained at the described positions [ ] in the slab. The analyses show no serious amount of gravity segregation. Microscopic examination from edge to edge of the slab showed little change in structure. From top to bottom there was a progressive coarsening of the grain size in the stirred slab but little change in the slab that was not stirred (Fig. I). No definite exhibit of segregation could be detected. In line with our experimental study on the tin-base babbitts, we cast an almost duplicate slab using A.S.T.M. Alloy No. 15, containing 0.9 to 1.25 per cent tin, 14.75 to 15.5. per cent antimony, 0.80 to 1.25 per cent arsenic and 0.4 per cent copper. The slab was 16 in. long and 3/8 in. thick, cast with the long side vertical. One slab was allowed to cool normally and the other was stirred continually during cooling. The pouring temperature of the babbitt was

Jan 1, 1944