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By Russell Franks, W. O. Binder

In recent years a considerable tonnage of the 18 per cent chromium and 8 per cent nickel steels has been used in lightweight high-strength structures that must be resistant to deterioration under atmospheric conditions. These steels are austenitic in character and their strength can best be increased by cold-working. Although a marked increase in tensile strength is obtained, claims have been made that the cold-worked steels do not possess fully satisfactory elastic propertics. Under certain conditions, however, this has caused no great concern, because, as explained by Ragsdale,1,2 he cold-rolled steels have been widely applied for construction of lightweight, high-strength trains using spot welding for joining purposes. Ffield3 agrees that the ease with which thin sections of the cold-rolled 18-8 steels can be joined by spot welding is greatly in their favor, but that they would be more satisfactory if higher elastic properties and a higher modulus of elasticity could be obtained. He states that, as far as the mechanical properties are concerned, the straight chromium stainless steel is superior to the cold-worked 18-8 steel, and in order to illustrate, he prcsented the data of Fig. 1, which also give a stress-strain curve for a low-carbon 13 per cent Cr steel. Ffield† proposed that columbium-bearing or titanium-bearing cold-rolled 18-8 steels be given a heat-treatment (preferably for 1 hr.) in the range 400" to 600°C. to precipitate carbides in order to obtain better mechanical properties. Discussions by Sutton,4,5 de Ganahl,6,7,8 Krivobok and Lincoln,' Knerr,l0 and Thaden11 have given further information on the properties of the cold-rolled 18-8 steels compared with other materials used in lightweight, high-strength structures. These investigators and others point out that the ultimate tensile strength of the cold-rolled 18-8 steel can be increased to 200,000 lb. per sq. in. or higher; Krivobok et al. indicate that

Jan 1, 1940

By A. J. Kesterton

MORE than 90 pct of the total tonnage of ingots made at Abbey Melting Shop is for steel sheet to specifications ranging between 0.055 and 0.07 pct maximum carbon. Since the rate of carbon elimination in the open hearth declines considerably as the carbon approaches these low levels, the use of oxygen for this purpose constituted a profitable field for development, particularly to increase ingot output. Development Several experiments were carried out initially in which water-cooled guns, originally of all-steel construction and later with fabricated copper heads, were introduced manually through a hole in the back wall of one of the 225 net ton furnaces, the oxygen being delivered about 4 to 6 in. above the slag. Successful blows were obtained, but manipulation of the gun was cumbersome. Application through the charging doors by means of bare steel lances was considered but rejected, because much of the scrap was light, necessitating a large number of buggies per charge, and consequent long occupation of the track in front of the furnaces by buggies. To construct an efficient mechanism it was decided to experiment with the introduction of the gun through a hole in the roof. This was eventually successfully achieved, with the following advantages. 1) The actual mechanism required is simplified, and can easily be remotely controlled. 2) No large steel framework projects out over the back platform, possibly interfering with tapping, and there is no danger of damage by casting cranes. 3) The railway track in front of the furnaces is left entirely clear for the passage of scrap buggies, eliminating interference with adjacent furnaces charging. 4) As compared with the use of bare steel lances, a water-cooled jet eliminates the manpower required to handle, control and change the bare pipes. 5) A jet through the roof can be situated over the center of the bath so that, whatever the direc-

Jan 1, 1958

By Arvid Anderson

THE weathering of copper-bearing ores with the formation of a water-soluble salt and the recovery of the metal by leaching and evaporation or precipitation, are processes long known, which have at various times been utilized with more or less commercial success. It is commonly assumed that the technical principles involved are quite simple and their application to a particular case easy. If these assumptions were true, we should anticipate a long list of uniformly successful leaching operations, which is not the case, and one would be justified only in calling attention to either unique or peculiar features of any particular enterprise; whereas, in studying the problems of the recovery of copper from the old workings of the Ohio Copper Co. in the light of available descriptions of other leaching projects, we have not found the assistance hoped for to guide us to the best realization of our own opportunities. It appears desirable, therefore, to call attention to these guiding principles, together with a description of the facts of accomplishment. Justification lies in the fact that the leaching and precipitation of copper at the Ohio Copper Co. mine in Bingham Canyon, Utah, is successful. This success is measured by an average monthly production of 600,000 lb. of copper at an average operating cost, to date, of 3.85 cents per pound at the company's workings, or 6.32 cents per pound after paying shipping and smelter charges on the finished copper. A total of 17,076,099 lb. of copper had been shipped to the smelter from the beginning of operations, August, 1922, to April 1, 1925. Probably these results can be bettered with further study and realization of the factors involved and the devising of methods of meeting them. It is now an assured fact that the enterprise will have a relatively long and continuously profitable life and that its reserves will not, nor cannot, be suddenly and permanently depleted.

Jan 9, 1925

By Carl H. Unruh, D. L. Katz

Experimental data are presented for hydrate formation conditions for gas mixtures of carbon dioxide and methane. Equilibrium constants for carbon dioxide, defined as the mole fraction of carbon dioxide in the gas phase (dry basis) divided by the mole fraction of carhon dioxitle in the hydrate (dry basis)... were calculated usine the equilibrium constants for methane developed in an earlier paper. INTRODUCTION A series of papers have been written on gas hydrates, giving temperatures and pressures at which hydrates would form.2. 3, 4. 5, 6. 9. 12, 13, 15 Vapor-solid equilibrium constants have been developed for methane, ethane, propane and iso-butane' by which it is possible to compute for a specific gas mixture the temperature and pressure at which hydrates will form. Carbon dioxide is present in many natural gases in concentrations usually from 0.1 to 2.0 per cent. It also forms a gas hydrate with water and presumably enters the solid solution when present with a natural gas which is forming a hydrate. The equilibrium constant giving the ratio of the concentration of carbon dioxide in the gas phase to the concentration in the solid phase is required for including the effect of the carbon dioxide when computing the conditions for hydrate formation. Direct determination of the concentration of carbon dioxide in solid hydrate requires a difficult separation to be made. Therefore, this research resorted to the measurement of the temperature and pressure at which specific mixtures of methane and carbon diox- ide would form hydrates. From the equilibrium constants previously mentioned for methane, it is possible to compute the equilibrium constant for carbon dioxide, without measurement of the composition of the solid phase. Fig. 1 shows the conditions at which methane and carbon dioxide form hydrates. The methane curve FG extents to some high pressure while the carbon dioxide curve AB intersects the vapor-liquid water-liquid carbon dioxide

Jan 1, 1949

By Carl H. Unruh, D. L. Katz

Experimental data are presented for hydrate formation conditions for gas mixtures of carbon dioxide and methane. Equilibrium constants for carbon dioxide, defined as the mole fraction of carbon dioxide in the gas phase (dry basis) divided by the mole fraction of carhon dioxitle in the hydrate (dry basis)... were calculated usine the equilibrium constants for methane developed in an earlier paper. INTRODUCTION A series of papers have been written on gas hydrates, giving temperatures and pressures at which hydrates would form.2. 3, 4. 5, 6. 9. 12, 13, 15 Vapor-solid equilibrium constants have been developed for methane, ethane, propane and iso-butane' by which it is possible to compute for a specific gas mixture the temperature and pressure at which hydrates will form. Carbon dioxide is present in many natural gases in concentrations usually from 0.1 to 2.0 per cent. It also forms a gas hydrate with water and presumably enters the solid solution when present with a natural gas which is forming a hydrate. The equilibrium constant giving the ratio of the concentration of carbon dioxide in the gas phase to the concentration in the solid phase is required for including the effect of the carbon dioxide when computing the conditions for hydrate formation. Direct determination of the concentration of carbon dioxide in solid hydrate requires a difficult separation to be made. Therefore, this research resorted to the measurement of the temperature and pressure at which specific mixtures of methane and carbon diox- ide would form hydrates. From the equilibrium constants previously mentioned for methane, it is possible to compute the equilibrium constant for carbon dioxide, without measurement of the composition of the solid phase. Fig. 1 shows the conditions at which methane and carbon dioxide form hydrates. The methane curve FG extents to some high pressure while the carbon dioxide curve AB intersects the vapor-liquid water-liquid carbon dioxide

Jan 1, 1949

By J. P. Van Kleunen

9.3-1. Introduction. The demands of industry for handling materials at higher rates and at reduced costs have had a very significant effect on belt conveyor technology. Although the general appearance of the belt conveyor today is essentially the same as it has been for the past several decades, the similarity ends there. Each component comprising the conveyor system has been continuously improved through design and materials technology to enable present conveyor systems to operate at ever-increasing rates and reliability. For example, twenty years ago the strongest commercially available, fabric-reinforced conveyor belting had a tension rating of 50 lb per ply-in. Currently, fabric-reinforced belts are available with ratings of 350 lb per ply-in. and steel cable reinforced belting is available with tension ratings of 3000 lb per in. of belt width (3). These technological advances have therefore enabled the belt conveyor to not only attain acceptance as a preferred method for in-plant movement of bulk materials, but also to be used for long distance transportation of bulk materials, particularly in areas of adverse terrain. The information contained in this chapter is intended to assist the reader to make basic decisions regarding the use and application of a conveyor system. The design of an overland conveyor transportation system or an in-plant process conveyor is accordingly beyond the scope of this article. Many comprehensive technical works covering the design of a belt conveyor are currently available from the manufacturers of materials handling equipment (6, 7, 9, 11). The design handbook published by the Conveyor Equipment Manufacturers Association is particularly recommended (2). 9.3-2. Conveyor Capacities. One of the most important factors in determining the proper size of a conveyor system is the rate at which material must be handled. Although tables and charts are available to the conveyor designer to assist him in his selection of conveyor components, only the

Jan 1, 1968

By Chester T. Sims, Robert I. Jaffee

The thermoelectric behavior of the Pt—Pt-Re thermocouple and the resistance of rhenium to attack by certain molten metals is discussed. In addition, data are presented on the stress-rupture behavior of drawn wire, the tensile characteristics of rolled sheet, the variation of Young's modulus with temperature, and the effect of specimen size and fabrication method on the work harden ability. Mechanical properties of thoriated rhenium are discussed. This includes data on the effect of thoria in rhenium on tensile properties, ductility, work hardening, and recrystallization. RECENT work by the authors', has described methods of fabrication and some of the physical and mechanical properties of rhenium. Rhenium was established as a high melting, dense, refractory-type metal with favorable mechanical properties. In addition, Todd and co-workers' and others" have studied such properties of rhenium as the work function, specific heat, and the resistance of rhenium to the water cycle. Revelation of these and other properties has led to serious consideration for application as electrical contacts, high temperature thermocouples, and wear resistant materials. chanical properties reported previously,' several additional examinations have been conducted. The stress-rupture behavior and the Young's modulus of rhenium have been investigated at elevated temperatures. Tensile data have been obtained for rolled sheet, and a study of the relative work hardening characteristics of rod, wire, and sheet has been conducted. Variation of Modulus of Elasticity With Temperature—The Young's modulus of a % in. diam annealed rhenium rod was determined from room temperature to 880"C (1620OF). The rod, approximately 6 in. in length, was activated in a transverse vibration apparatus suspended in a furnace. The resonance frequencies of the rod were measured and used to calculate the moduli values. The driven frequency was 569 cycles per sec, and a protective helium atmosphere was used. The data, plotted in Fig. 1, show that the modulus decreases in an approximately linear manner with temperature over the range tested.

Jan 1, 1957

THE story of Miami really is two stories. First, that of an excellent Porphyry Copper mine, ably managed as a business enterprise, and always among the leaders in technical progress. Concentrating its first ore in 1911, it had by 1925 paid dividends totaling $30,000,000 or $40 per share on stock that had cost the public $5 per share in March, 1908. The ore, containing 2.5 per cent copper at the start, had become progressively leaner but the recovery had tended to improve. Production costs had gone up during the World War and the early post-war period; and had come down again. In all these respects it had followed the norm. If the mine had been abandoned as exhausted and the company had been liquidated late in 1925 (a program that had been given earnest consideration in 1924), Miami would have gone down into history a first-rate mining venture; as an active and progressive participant in the great Porphyry achievement. But Miami was not liquidated in 1925; instead it started to write the record of its second and really amazing story. Near the old mine was a large body of low-grade ore containing, in place, less than 20 lb. of copper to the ton, and without, incident- ally, any considerable sweetening of gold and silver. Any method of underground mining that was cheap enough would certainly entail some dilution, so that ore as sent to the concentrator necessarily would average much less than 20 lb. As a matter of record, the average for 1929 was 16.6 lb., from which 11.726 lb. was recovered as concentrate. As already said, the exhaustion of the older orebody during 1925 was foreseen; but in 1924 the decision was reached to enlarge the concentrator and develop a new mine. An expenditure of $2,500,000 was entailed in this program. By October, 1925, the

Jan 1, 1933

By Eugene A. Stephenson, Leon J. Pepperberg

The natural gas industry is essentially a byproduct of the oil industry. When first discovered the gas was usually regarded as a nuisance, and even when found immediately associated with oil, or suspected to be so, it was customary to blow it freely into the air, in the hope that gas would shortly be replaced by a flow of oil. The early methods of production,' transportation, and utilization were neither economical nor efficient; the chief value of gas was based on its use as a fuel, with no regard to (1) its effect. upon the oil with which it was associated, (2) its importance as a lifting agent, or (3) to its possibilities for the manufacture of byproducts. The spread of scientific research among major gas and oil companies, manufacturers, and academic groups, has gradually brought recognition of the fact that many of the technical problems bearing on production, transportation and utilization are common to both the gas and the oil industry. A few of the problems that have received serious study, and from which highly gratifying results have been obtained, are: (1) gas measurement, (2) oil well and gas well capacity tests, (3) elimination of field waste, (4) design of pipe lines and compressor stations, (5) extraction of constituents which might interfere with the normal flow of gas through the line, (6) control of reservoir pressure, (7) estimation of reserves of both oil and gas, (8) control of water encroachment, (9) measurement of factors which influence fluid movement through sands, (10) solubility of gases in oils, (11) effect of dissolved gases upon the properties of the solution. These investigations have demonstrated that almost every problem relating to oil production also involves some phase of natural gas engineering. During the past 15 years the use of experimental methods for the discovery and measurement of obscure, influencing factors, which cannot be determined purely by hydrodynamic or thermodynamic analyses, have contributed much towards the progress made in solving the problems of the oil and gas industries. Most of the experimental work on

Jan 1, 1934

By Russell Franks

IN recent years a considerable tonnage of the 18 per cent chromium and 8 per cent nickel steels has been used in lightweight high-strength structures that must be resistant to deterioration under atmospheric conditions. These steels are austenitic in character and their strength can best be increased by cold-working. Although a marked increase in tensile strength is obtained, claims have been made that the cold-worked steels do not possess fully satisfactory elastic properties. Under certain conditions, however, this has caused no great concern, because, as explained by Ragsdale,1,2 the cold-rolled steels have been widely applied for construction of lightweight, high-strength trains using spot welding for joining purposes. Ffield3 agrees that the ease with which thin sections of the cold-rolled 18-8 steels can be joined by spot welding is greatly in their favor, but that they would be more satisfactory if higher elastic properties and a higher modulus of elasticity could be obtained. He states that, as far as the mechanical properties are concerned, the straight chromium stainless steel is superior to the cold-worked 18-8 steel, and in order to illustrate, he presented the data of Fig. 1, which also give a stress-strain curve for a low-carbon 13 per cent Cr steel. Ffield? pro-posed that columbium-bearing or titanium-bearing cold-rolled 18-8 steels be given a heat-treatment (preferably for 1 hr.) in the range 400° to 600°C. to precipitate carbides in order to obtain better mechani-cal properties. Discussions by Sutton,4,5 de Ganahl,6,7 8 Krivobok and Lincoln,9 Knerr,10 and Thaden11 have given further information on the properties of the cold-rolled 18-8 steels compared with other materials used in light-weight, high-strength structures. These investigators and others point out that the ultimate tensile strength of the cold-rolled 18-8 steel can be increased to 200,000 lb, per sq. in. or higher; Krivobok et al. indicate that

Jan 1, 1940

By J. M. Donkers, R. de Groot

The various objectives of dredging at sea require different methods and radically different equipment for their optimum fulfillment. In the majority of cases, sea dredging is done by means of dredging equipment connected to a pontoon or ship floating at the surface. As the supporting hull is subject to the influence of waves, swells, currents and wind, the connecting point of the dredging equipment to the hull will generally move relative to the sea bottom with 6° of freedom. The more important hull motions are surge, heave, pitch and roll. Depending on the actual sea and weather conditions and the size of the hull, some of these motions can be so large that dredging equipment of rigid construction (normal or inland dredges) cannot be used. In those cases where mechanical disintegration of the bottom is necessary and where accurate dredging is required, the designer must find a solution for this problem. For cases where the bottom consists of soils that can be handled by plain suction, highly sophisticated dredging equipment such as the trailing suction hopper dredge permit dredging under all but the most severe sea state conditions. This type of dredge picks up the soil from the sea bottom while slowly underway. The drag suction head is fitted on a suction pipe of such flexibility that the supporting ship can carry out all six movements in relation to the draghead (heave, pitch, roll, sway, yaw and surge), while the draghead remains in firm contact with the bottom. The suction pipe is fitted with flexible hoses, a universal hinge, a horizontal hinge, axial turning gland and sliding turning gland with horizontal axis and is suspended flexibly from the ship incorporating swell compensating buffer gear, keeping the wires taut and the draghead bottom contact pressure fairly constant while the dredge moves up and down. Due to the fact that the draghead has a low bottom contact pressure and has little tendency to sink into the bottom, this compensation is not difficult to realize.

Jan 4, 1974

By F. N. Rhines

Despite the large amount of study which has been devoted to the subject our present knowledge of the copper-oxygen system remains incomplete and unsatisfactory .in many respects. This applies particularly to those regions in which solid metallic copper exists. The primary object of the present paper is the contribution of new information relative to the solid solubility of oxygen (or cuprous oxide) in copper at atmospheric pressure, together with certain observations in the low-pressure regions of the system. It seems appropriate also to present a brief summary of the outstanding previous work on the constitution of mixtures of copper with its lowest oxide in order. to show the relation between the new facts and the system as a whole. The earliest recorded investigations of the copper-oxygen system are those of M. S. Lucas(l) $ and of M. Chevillot(2) in 1819 and 1820. Lucas believed that liquid copper is capable of dissolving its oxide, but neither he nor Chevillot was able to furnish convincing proof of this property. It was not until 1866 that T. Graham(3) definitely established the existence of such a solubility. Nine years later W. Hampe(4) measured its extent and roughly outlined the copper-rich portion of the system. The first really precise examination of the constitutional relationship between copper and cuprous oxide, however, was that of E. Heyn(5) who in 1900 published a temperature-concentration diagram covering the range from 0 to 10 per cent of cuprous oxide at atmospheric pressure. Within these limits of composition cuprous oxide was found to dissolve in liquid copper, forming at 3.4 to 3.5 per cent a eutectic which melted at 1065" C. R. E. Slade and F. D. Farrow(6) extended these studies to mixtures of higher oxygen content. They discovered that between 20 and 95 per cent of cuprous oxide the metal and oxide form two liquid phases at a monotectic reaction of 1195" C. The span of the biliquidal region diminishes slightly

Jan 1, 1934

By Robert W. Hunt

The American Institute of Mining and Metallurgical Engineers was the first American technical organization to consider steel-rail specifications and sections. If I am not mistaken, the first contribution on those subjects to the Proceedings of the Institute was presented by Prof. Thomas Egleston, in 1874, and was entitled "Investigations on Iron and Steel Rails made in Europe in the Year 1873.1" The next contribution was Dr. C. B. Dudley's report of his investigation for the Pennsylvania Railroad of the wear of steel rails in their tracks, in 1878, which contribution led to a very memorable discussion that extended through several meetings.2 In 1880, Mr. C. P. Sandberg3 presented an article on rail specifications and inspection and rail sections. This was followed, in 1881, by A. L. Holley,4 in his exhaustive report on the then used American rail sections. The next contribution, I believe, was made by myself5 at the Buffalo meeting, in 1888, on steel-rail specifications, which I followed,6 in 1889, by a paper on steel-rail sections. Since that time there have been numerous contributions to the Transactions of the Institute in relation to the manufacture of steel rails. The American Society of Civil Engineers officially took up the investigation of the relation of rail sections to the wear of car wheels in 1888. In the prosecution of this work, the Society appointed a special committee, whose labors extended through several years and resulted in an exhaustive report to the Society in 1893.7 Later, another committee was appointed to consider specifications for the manufacture of steel rails; the labors of this committee extended over a period of several years, a final reporta being made in 1910. It was my fortune to be the secretary of both of those committees. The American Society for Testing Materials, organized in 1899, took up the consideration of rail specifications and is still giving attention to that subject through its established procedure of investigations by committees. In 1900, the American Maintenance of. Way Association was organ-

Jan 1, 1920

By Paul R. Martin, R. B. Kelly

The area comprising what is geographically termed "Central Texas" was somewhat less active in 1934 than in 1933. The year saw the completion of 182 dry holes and only 74 producing wells. Bexar, Williamson and Bastrop counties, with active fields such as Yturri-Southton, Byersville, North Dale and Cedar Creek contributed a majority of the new oil wells. Hilbig, in Bastrop County, 1933's most important discovery in the district, saw no development during the current year. New fields opened in 1934 were Byersville, a serpentine intrusion in Williamson County, and Manda, producing from similar material in Travis County. Like most of the other serpentine plugs, neither gives promise of covering a very large area. Other active counties were Bexar, Bastrop and Caldwell, although successful operations in each of them were limited to the old fields. The location of producing fields is shown on Fig. 1. New Fields Byersvil1e.—Late in 1933, Fritz Fuchs completed Zeischang No. 1, eight miles south of Taylor, Williamson County, for an initial production of 25 bbl. per day. The oil is 37" B6. A.P.I. gravity and is from Serpentine formation at approximately 900 ft. Additional drilling was carried on in 1934, and at the end of the year 18 producing wells had been completed, proving about 200 acres. Manda.—The Manda field, or Kimbro field as it is termed by some, received its first production Sept. 10, 1934, when the Humble Oil & Refining Co. completed No. 1 C. J. Peterson as an 8-bbl. oil well. The new field is near Littig, in eastern Travis County, and is about 15 miles northeast of Austin. Production is found in serpentine formation between 650 and 750 ft. The same company's No. 1 Buck Christian, second well in the field, flowed 190 bbl. per day through a ?-in choke. Although only a small area has been definitely proven it is expected that present drilling will provide extensions in several directions.

Jan 1, 1935

By Major N. R. Junner

Although manganese-garnets are rarely seen in hand specimens of the manganese ores and associated rocks, they have been detected by the writer in thin sections of all the ores and wall rocks that have been sliced, with the single exception of the Insuta deposit. Rhodonite, and an almost colorless amphibole, which appears to be manganiferous, are less common. Types of Occurrence (a) Rocks Composed of Manganese-garnet and Quartz The best known examples of this type are from near Bole and Wa in the Northern Territories of the Gold Coast, and from near Chama in the Gold Coast Colony. Normally these are fine and even-grained rocks, in which the garnets cannot be recognized in hand specimens. They are often stained with secondary manganese oxide. Thin sections examined microscopically are seen to be composed of aggregates of minute crystals of garnet in a matrix of mosaic quartz. Some manganese oxide and braumite (?) is often present, but other minerals are exceptional. The relative proportions of garnet and quartz in these rocks vary greatly and there is a complete gradation from quartz-rock to garnet-rock. (6) Rocks Composed Mainly of Manganese-garnet and Manganese Oxides Rocks of this type are known from Kalimbi Hill near Siripe, Pabini Hill near Bangwon, near Odumase and Konongo, and in the Ya Ya creek, about 5 miles east of Dunkwa. These are usually fine-grained banded dark-colored rocks, composed of abundant minute garnets in a matrix of black manganese oxide and braunite (?). A little microcrystalline is often present, and occasionally a little colorless amphibole. quartz (c) Rocks Composed of Rhodonite and Manganese-garnet Rocks of this type are not common. They are known from near Chama, and from the road between Senyong and Mangkuma. Some quartz is usually present. All these rocks resemble closely in texture and composition certain rocks from India, described by Fermorl as "gondite;" and they also resemble certain rocks described by Derby2 from the Queluz district,

Jan 1, 1927

By George W. Maynard

For an account of the discovery and the determination of chromite on Port au Port Bay I am indebted to Mr. Obalski, Government mining engineer for the Province of Quebec. He writes: " In June, 1894, with the authorization of our Government, I went to Newfoundland to examine some asbestos property. Passing through Halifax, I had interviews with some gentlemen who told me that besides the asbestos there was in the same district a big deposit of iron-ore. They handed me some specimens, and, after ascertaining that they were not magnetic, and learning that they were found in serpentine, I said they were chromic iron. I visited the place on June 27, 1894, and confirmed my opinion, pointing out at the same time the importance of the deposit, as appears in my report of July 9, 1894. I do not claim any credit for the discovery of chrome-ore in Newfoundland; but, as a matter of fact. when I came in contact with the Halifax gentlemen they did not appear to know the nature or the value of the mineral until I mentioned to them that it was chromite. "' Mr. Obalski's report was mainly devoted to the asbestos-deposits. That portion relating to the chromite was as follows: " On the right side of the creek there is a show of chromic iron of good quality, which appears scattered through the serpentine in several places on the face of the cliff for 40 to 50 feet. A few boulders are found farther up at a distance of 100 feet, and also in the ckeek itself. From this point the deposit exists on a relatively large area, the widest exposures being from 6 to 7 feet. Chromic iron deposits in serpentine rock have no regularity, and are merely pockets. In the case of the property in question this rule is not changed, but the pockets look to be of large extent, and could be easily worked." My own preliminary investigation of the property was made

Jan 1, 1898

By Howard L. Hartman

6.1-1. Introduction. Of necessity, the first of the unit operations conducted during the exploitation phase in surface mining is production drilling. It precedes blasting, with which it is associated as the two unit operations employed to break or fragment consolidated material (usually rock) in place. The purpose of production drilling is to provide the cavity for placement of the explosives. So far, no alternative to blasting has been devised for fragmenting very resistant rock in situ, although some forms of excavation (ripping, bucket wheel) are suitable without prior blasting for softer rock, such as weathered shale or mudstone, decomposed sediments, etc. For the vast majority of surface mines, however, drilling and blasting are pre- requisite to excavation and essential to the production cycle. Drilling is also used in surface mining for purposes other than providing blastholes. It finds application during exploration for obtaining samples and during development for drainage, slope stability, foundation testing, etc. Only in the exploitation phase of surface mining, however, are unique or specialized drilling methods and equipment employed; and the discussion in this Section is directed primarily to that application of drilling. Drilling is the most common means of rock penetration, the operation of placing a directed hole in rock. Closely akin to drilling for exploitation purposes is the cutting or freeing of dimension stone in quarrying. This operation, usually termed channeling or sawing, also takes the form of directional penetration of rock; but instead of producing a cylindrical hole, it yields a kerf or cut. The material thus freed from the solid is both a shaped and sized product, an objective of vital importance in the dimension stone industry. In sawing, holes are sometimes drilled to insert tools, but this drilling is a minor part of the sawing operation and employs conventional methods. Cutting, as a unit operation for freeing stone in quarrying, may be considered equivalent in purpose to drilling and blasting in other forms of surface mining.

Jan 1, 1968

By S. Paul Lindau

THREE years ago it was decided by the management to granulate the matte that is produced in the smelter of the St: Joseph Lead Co. at Herculaneum, Mo., thereby doing away with a large amount of labor in handling the matte and in subsequent crushing. On Mar. 1, 1915, the granulator was put in operation and up to Jan. 1, 1916, 18,735 tons had been, granulated. The four blast furnaces have a daily output of about 280 tons of pig lead and 100 tons of matte assaying about 11.0 per cent. Pb. It is expected that projected improvements in roasting methods will eliminate more sulphur from the charge, and cut down the matte-fall, to about one-half of the present figure. The blast furnaces are tapped into movable forehearths or settlers, 6 ft. by 4 ft. by 22 in., the slag overflowing into 27-cu. ft. slag cars which are hauled to the clump by electric locomotives. Previous to the adoption of granulation, the matte was tapped from the forehearths into small slag pots which were dumped after cooling. The matte cakes were broken with sledges, and transported to the crushing plant for fine crushing and screening. Here the matte was reduced to ¼ -in. size before being fed to the roaster bins.. A Wedge and a Holthoff mechanical furnace are used for preroasting before sintering on the Dwight and Lloyd machines. The matte is returned to the furnaces as an iron flux until the .gradually accumulating copper content reaches about 7 per cent., after which it is put aside to be concentrated in a small copper blast furnace, the resultant high-grade matte-being sold. When the matte does not settle readily from the slag, two settling devices are often used, the second one being a large catch-pot, which gathers any matte that may overflow from the forehearth, the slag then overflowing from the catch-pot into the slag cars. When full of matte, the catch-pot is removed, allowed to cool, and the contents broken and crushed.

Jan 10, 1916

By I. N. Knapp

Introduction.-The special object of these notes is to describe the mixing, testing, and use of mud-ladened water for rotary drilling in such a way as to make them helpful to the driller, the operator, or the engineer in solving his own special drilling problems. The structures, apparatus and tools used are indicated in a general way. No attempt is made to describe the art of rotary drilling; only such description as are necessary to make plain the use of mud are given. The information is the result of actual experience in drilling in Coastal Plain formations. The materials encountered in the wells drilled were unconsolidated sands, gravels, and clays, in which thin layers of sandstones, shell conglomerates, and shales began to appear at about 1,200 ft. in depth, although one well was drilled to 3,018 ft. without encountering any cemented or indurated materials. Unusual Conditions.-The general surface of the ground where the drilling was done being hardly a foot above mean tide, and the daily tidal variation being about 15 in., it was found necessary to plank over the sod surface with 3-in. plank to work from. A 30 by 30 ft. planked area was sufficient to carry the derrick with equipment and 2,500 ft. of 4-in. drill pipe stacked in it. The derrick was set up 3 ft. on cribbed blocking arranged to spread the load over the planking. The engine, boilers, and pipe yard were also carried on 3-in. planking. Drilling Outfit.-This consisted of a derrick, 20 by 20 ft. and 84 ft. high, two 35 h.p., "oil country" boilers, one double 8 ¼ by 10 in. reversible engine, two 10 by 6 by 12 in. duplex mud pumps, one 15-in. rotary, "hoisting works" with chain drive, hoisting block with line, crown block with pulleys, rotary' jetting swivels, hose, complement of tools, pipes and connections, and. a mud mixer, with engine.

Jan 12, 1914

I would like to congratulate the authors on an interesting paper and, in particular, on their justification of the use of superposition in treating gas wells. They state, however, that no theory has previously been developed lor treating the variable rate drawdown case. In a paper published a few years ago by my colleagues and myself, a method is described which allows a constant rate drawdown curve to be derived for any well. regardless of real rate variations. This method has the great advantage that it is not necessary to make any assumptions regarding the form or uniformity of the reservoir, and the derivation suggested by the present authors is simply an idealized case of our more general treatment. In the light of several years' experience in the derivation of constant rate drawdown curves: I would like to point out that the method proposed by Odeh and Jones may lead to confusing answers, particularly if applied over an appreciable time interval. The reason is that, if pressures are measured when a well is flowing, non-linearities in plots like Figs. 1 and 2 can arise due to either (1) changes in the skin factor with time and/or flow rate, or (2) an inhomogeneous reservoir. Separation of these two effects is only possible if some of the pressures used in the analysis are measured when the well flow rate is 0 or, in other words. during brief shut-in periods. REFERENCES 1. Arthur, K. B.. Metunomski, Z. G. and Ruche, Ms "Intetet ct methode d'utilisa tion des mesures de pression [)our Petude des gisemonts" Revue de T'I.F.P. (Nov., 1962) XVII, 1299. 2. Thomere, R. and Arthur, K. R.: "Analysis of the Pressure Bet~avior of a Production Well Subject to Interterence and Its Application to Reservoir Models", Paper SPE 1189 presented at SPE :Amund Fall Mecting Ireld in Denwer, Colo. (Oct. 3-6, 1965).

Jan 1, 1966