Search Documents

Discussion -of the paper of I. N. KNAPP, presented at the New York meeting, February, 1915, and printed in Bulletin No. 96, December, 1914, pp. 2783 to 2793. A. C. LANE, Tufts College, Mass.-Is there any noticeable effect in drilling against salt water? Mr. Knapp says that the mud settles very quickly when brine is added-. What is the effect when you strike a strong salt water ill boring? I. N. KNAPP.-You are supposed to have enough mud pressure in your well to keep the saltwater out. I have drilled against what I knew to be 80 ft. head of water, and hot water too at 99.5°; this water did not show until the well was bailed and the mud pressure reduced. HENRY Louis, Newcastle-upon-Tyne, England (communication to the Secretary*).-Mr. Knapp may be interested to learn that the use of mud in drilling through porous strata is much older than lie appears to be aware of. It has been used notably by Honigmann for boring shafts in Holland and in some of the adjoining portions of Germany. At the Oranien Nassau colliery, shafts about 12 ft. in diameter and 425 ft. deep were sunk in. this way-namely, by boring with a rotary borer, a thick mud puddle being pumped into the shaft, so as to maintain a pressure in the shaft greater than the hydrostatic pressure in the surrounding loose sands and thus keeping the sides of the shaft from collapsing. He will find references to this method in Das Abbohren von Schächten; Handbuch der Ingenieurwissenshaften, p. 134, also in the Transactions of the Institution of Mining Engineers, vol. xiii (1896-97), p. 155. The process appears to have been employed even before 1895, though I cannot give the exact date when it was first used.

Jan 5, 1915

By Dr. Hans Von Höfer

APART from the hypothesis of a .cosmic origin (which failed of acceptance because it was not adequately supported by facts), the only important controversy concerning the origin of petroleum has been, for a long time, between the advocates of inorganic and of organic origin respectively. Each of these theories has had a long history of development, and is still being perfected, under the influence of two causes: (1) the increasingly extensive and thorough study of the oil-fields (of which new examples are periodically discovered and opened); and (2) the progress of synthetic experiments devoted to this question. Moreover, the advance in our physical and chemical knowledge of the properties of this peculiar natural product has necessarily modified all criticism of conflicting views. I. THE HYPOTHESIS OF INORGANIC ORIGIN That the notion of an inorganic origin of petroleum, first set forth by Berthelot in 1866, and afterward ingeniously developed and formulated by Mendelejeff, should thus have proceeded chiefly from chemists, is quite natural; for the question was one of possible chemical processes in the earth's interior, and of imagined chemical reactions to be, verified by experiment. Hypotheses of this kind were suggested by many chemists, of whom two, P. Sabatier and J. H. Senderens, may be specially named by reason of their highly interesting chemical experiments. Among geologists, Mendelejeff's hypothesis was received at first with much interest and favor; for it rested on the assumption of a central terrestrial mass of iron carbide, and the geologists had good reasons for adopting that assumption. Yet comparatively few of them attempted to furnish geological proofs of the hypothesis: the majority either silently believed in it, or for one or another reason rejected it altogether.

Jan 5, 1914

By Takeyasu Ito, Mayumi Someno, Kazuhiro Goto

SINCE the pioneering work by Kiukkola and Wagner,1 many experiments have been reported on solid electrochemistry at elevated temperatures. However, the studies have been confined to experiments under isothermal conditions. One may conceive many situations under nonisothermal conditions. With two different temperatures T1, and T2 at the two electrodes, the electromotive force, E of a Galvanic cell will be expressed by the following equation under a steady state heat transfer in solid electrolytes of zirconia-lime and thoria-lime. E = ^ $ l&-dGO2+a(T2-Ti) [1] where tO2- is the transference number of oxygen ions in the electrolyte, Go, is the chemical potential of oxygen, and a is the coefficient of the thermoelec-tromotive force due to the temperature difference. The objective of the present study was to evaluate the coefficient of the thermoelectromotive force for zirconia-lime and thoria-lime under isobaric condition. The physical meaning of this coefficient is out of the scope of the present communication. The experimental cell assembly is schematically shown in Fig. 1. The zirconia-lime electrolyte tube and thoria-lime electrolyte tube were 8.0 mm OD and 5.0 ID, from commercial sources with chemical analyses of 94.8 wt pct ZrO2, 3.85 pct CaO, 0.83 pct SiO2, 0.25 pct TiO2, and 0.05 pct Fe2O3; and 95.0 pct ThO2, 4.0 pct CaO and rare earth metal oxides, respectively. The specific gravity was 5.5 g per cu cm for zirconia-lime and 9.8 g per cu cm for thoria-lime. Original powder size before shaping and sintering the tube was several microns for both electrolytes. The distance separating the two electrodes was 4.0 or 5.0 cm. Platinum wire of 0.5 mm diam was used for the electrodes. The temperature gradient was controlled by heating one electrode with a small heating coil of nichrome wire. The temperatures at the two electrodes were measured with two calibrated Pt-13 pct Rh:Pt thermocouples, directly contacting the two platinum electrodes. The atmosphere was either air or pure oxygen. The partial pressure of oxygen in air was considered equal at the vicinities of the two electrodes, with negligibly small thermal segregation in the gas phase. The difference of the chemical potential of oxygen was controlled only by the temperature difference at the two electrodes and not by the oxygen pressure difference. The temperature ranges were 600" to 1200°C for zirconia-lime and 850" to 1200°C for thoria-lime electrolytes. Fig. 2 shows the relation of the measured electromotive force and the difference of the oxygen chemical potential at the two electrodes for zirconia-lime and thoria-lime electrolytes. The electromotive forces in the figure were measured by a *0.05 mv potentiometer. The chemical potential difference was calculated by the following equations.'

Jan 1, 1970

By Nelson Severinghaus

FOLLOWING the end of hostilities of World War II, a resurgence of industrial and home building has given impetus to the use of many products of the stone industry. Shortage and high prices of some building materials such as lumber have aided wider acceptance of materials such as concrete products which have been relatively plentiful and which have not risen so rapidly in price. Ingredients for many of these substituting materials come from the stone industries, often from by-products of stone operations. Most of the tonnage of the stone industry in the State of Georgia comes from granite and marble. There are extensive dimension stone operations in granite in the Elberton and in the Lithonia areas. Building and monumental marble from the Tate area has been used throughout the country. Cutting operations in both types of stone have their by-products in faulty blocks and in spalls. In the State there are three large crushed-stone plants utilizing granite, one near Camak, one near Lithonia and one at Stockbridge. All have had excess fines or screenings in the past but this excess is largely disappearing with development of new uses. At times this "waste" has amounted to as much as 20 pct of the stone quarried. Handling of this large tonnage from point of screening out to storage piles presented a costly problem and large areas were taken up by the piles. Crushed stone is generally sold with a relatively narrow margin of price over cost, so any elimination of disposal cost or increase of income by marketing of by-products is highly desirable. BY-PRODUCTS OF GRANITE DIMENSION STONE It sometimes becomes difficult to differentiate between main product and by-product. In the cutting of granite dimension stone in the Lithonia district of Georgia, a considerable quantity of remnants of uneven shape and size is produced. The larger of these pieces have long found use as building rubble, particularly for retaining walls and building foundations (Fig I). They are broken down to one man size by plug drilling and wedging and by hammer. In recent times, demand for this former by-product has grown so that quarries have been opened for the production of rubble as a main product. Local masons have attained skill in using these irregular shapes to form economical and attractive walls. Areas such as Elberton, Georgia, which do not have a large building market nearby, tend to accumulate piles of large pieces of reject stone. When a road job or other local construction offers a quantity market for crushed stone, a portable crusher works this material down to crushed aggregate. Spalls and finer chips from granite stone-cutting operations have generally found their way into crushers and thence to the many uses for crushed aggregate. One company near Lithonia started marketing the smaller by-product crushed sizes for chicken grit about ten years ago. This use has grown to nation-wide distribution and the tonnage is now so great that they have opened a large quarry with

Jan 1, 1947

By W. E. Gaby

THE form of dip chart here presented for the use of the profession was devised by the author when he was confronted with a particularly heavy job of geological section making and. did not have any of the usual tables or charts at hand. This was at the property of the Teziutlan Copper Co. in Puebla, Mexico, where the orebodies are much faulted and lie conformably with a slightly inclined and. much folded schist. Because of the low dip and the folding of the orebodies, the engineering, and geological data respecting them were best represented on vertical cross-sections quite closely spaced. A less finished form of the chart was published in the Mining & Scientific Press of Aug. 6, 1921, with an explanation of its use. I have checked the new drawing for accuracy against the calculated table given, and constructed an explanatory diagram beneath. As some geologists are accustomed to using the table, I have included it, since no advantage is obtained by mere interpolations from the chart to get the required angle, except as it gives a mental picture of this angle. The chart gives a more rapid and much easier solution when cases multiply so that it becomes desirable to eliminate the tedious manipulations of a separate protractor. In fact, using the parallel ruler as des-cribed, it is not even necessary to make note of the angle sought. It is brought out graphically, leaving the mind free to note the correlations. The chart itself may be made more convenient by reproduction on celluloid with a slot running on the zero line of the protractor.

Jan 9, 1922

By E. E. McGinley, L. D. Woodworth

DURING the past several years has occurred what, in the light of future events, may aptly be called the rebirth of the acid Bessemer process. The increased attention given to the technical and metallurgical details involved in the production of Bessemer steels has been exceedingly fruitful, and indicates the value of further research and plant development. In times like these, when the steelmaking capacity of the country is operating at a maximum rate to supply materials for the national defense program, it behooves the Bessemer operator not only to strive to increase production but also to maintain a high standard of quality. The opportunity is ripe, it seems, to recapture fields of application once considered the birthright of Bessemer steels, but supplanted in recent years by open-hearth grades. This involves cooperation all along the line, from the blast-furnace operator to the metallurgical contact man and salesman. The metallurgist's part in this program involves the study of the many steelmaking variables and the measures necessary to ensure constancy in the finished product. It is equally important that the knowledge gained be disseminated widely to ensure the wise application of Bessemer steels in new fields. The merits of Bessemer steels for certain work are well understood. The combined properties of good weldability, machinability and stiffness are unique and fully explain the strong entrenchment of Bessemer steels in certain fields; e.g., skelp for small butt-weld conduit, screw steels machined in automatics, and certain tinplate applications. It is the purpose of this paper to review briefly the physical properties of Bessemer steels as contrasted with those of open-hearth steels, to discuss control measures now employed in the making of Bessemer steel, and to consider the advantages derived from the use of these control measures. PHYSICAL PROPERTIES OF BESSEMER VS. OPEN-HEARTH STEELS A number of Bessemer blows and open-hearth heats were tested for tensile strength, ductility and impact strength. The steels selected were confined to sections from ¾ to 1 ¼ -in. diameter, inclusive, and the carbon content covered was sufficient to yield parallel ranges in ultimate strength for the comparison. Other factors, such as the extent of deoxidation of the steel and variations in chemistry, were kept as comparable as possible. Machined test pieces of 0.505-in. diameter with an 8-in. gauge length were pulled. The data obtained are shown in Fig. 1, ultimate strength being plotted against carbon content. This graph shows that for equivalent carbon content Bessemer steel has on the average 15,000 lb. per sq. in. greater tensile strength and, conversely, for the same tensile strength Bessemer steel requires on the average 0.14 per cent less carbon. The average phosphorus content for the Bessemer steel was 0.090 per cent,

Jan 1, 1941

By James Douglas

No one mill attribute it to the partiality of friendship if I claim for Thomas Sterry Hunt the right to a place among that little band of men whom nature has endowed with what seems an almost magical power of insight into her mysteries. But those of us who knew him well, while me never ceased to wonder at the breadth of his genius, the fertility of his imagination, and the wonderful capacity of his memory, learned that these native powers would have availed little to win him his rank in science, had they not been stimulated by ceaseless mental activity, indomitable perseverance, and unflagging industry. Thomas Sterry Hunt was born in Norwich, Connecticut, on September 5, 1826. He came on his mother's side from that good old stock which gave to Puritan England the gentle mystic Peter Sterry and that uncompromising preacher Thomas Sterry, who wrote the notable tract, " The Rot among the Bishops " in 1667, and that gave to New England Consider and John Sterry, the mathematicians. While lie was a child the family moved to Poughkeepsie on the Hudson. There the father died when Thomas, the oldest son, was twelve. The mother and her family of six young children returned to the old home in Connecticut. For a short time Thomas attended the public school; but it was for a short time only, as he, thus early, was required to share the burden of the family support and to seek employment. This he found first in a printing-office, then with an apothecary, afterwards in a book-store. The surroundings may have been congenial, but the occupation probably was not; for he re-

Jan 1, 1893

By Mack H. Shumate

1 Raw coal from Truax-Traer Coal Co.'s Burning Star Slope mine, Jackson County, Ill., is brought to the surface by the new 42-in. slope belt haulage conveyor at the rate of 850 tph. The loading system shown above employs four storage tracks, two tail tracks for loading, and four 25-hp hoists, operating in pairs, and coupled to two dolly cars to move the trains of cars through the tipple. The system has a capacity for loading 1800 tph. One operator is needed to load on each of two shifts. A third man working for a few hours on night shift sets up for the morning cycle. Railroad crews bring in empties placing them in the storage yard, twenty cars to the track. Trains of empties are pulled through to the tail track and loaded on the return; hoists at opposite ends pull the trains in each direction. [ ] 2 Pairs of hoist drums are interconnected electric- ally by a Trench lay cable buried between the tracks. When one hoist operates moving the cars, the tail hoist idles with brake released. The operator, situated in the tipple over the cars, views the storage yard at the end of the first shift (left). When returning loaded cars to yard, four or five cars are held on the dolly to couple the next string of empties. Empties are ready for loading on the tail track (right). Differing from a gravity system in which empty and load tracks are on a slight grade, this system is designed for 80 railroad cars for a two-shift operation and one rail service per day.

Jan 6, 1962

By A. B. Young

THERE were produced in this country in 1923 probably in the neighborhood of 12,000 or 13,000 tons of refined and crude arsenic, by far the greater portion coming as a by product of smelting operations. Early this year copper smelters were producing arsenic at the rate of about 425 tons per month and lead smelters at the rate of 7;0 tons per month. During the entire eighteen years prior to 1919, there were produced in the United States only 47,000 tons of arsenic, which amounts to only 25 per cent. of the present output. The great increased demand has come about through the augmented use of arsenates as insecticides and arsenates as weed killers. In an extract from "Mineral Resources of the United States" on "Arsenic in 1922," Messrs. Heikes and Loughlin say, "The minimum possible demand for arsenic in 1923 was estimated at the end of 1922 to be about 13,000 tons, including 2000 tons for plate glass manufacturers, 3000 tons for lead arsenate, 3500 tons for calcium arsenate, 1500 tons for weed killers, 1200 tons for Paris green, 1000 tons for sheep dips and 750 tons for proprietary mixtures. More recent information, however, indicates twice as great a demand for calcium arsenate." The latter has found great use in the last three or four years as a weapon to combat the boll weevil pest of the southern cotton belt. ~t the present writing refined white arsenic is being quoted on the New York market at from 13)d c. to 1455 c. per Ib., while the average price during the eighteen-year period just mentioned was 4.8 c.

Jan 1, 1924

By Benjamin LeRoy Miller, Joseph T. Singewald

The ore deposits at Firmeza have been worked continuously since 1884; those at Daiquiri since 1895. It is surprising, therefore, that they have not been the object of careful geologic study until quite recently. It is true that considerable attention was paid to these deposits by A. C. Spencer, in 1901, in the report on the geology of Cuba, by Hayes, Vaughan, and Spencer,l but this was only incidental to a hasty general reconnaissance of the Island. As far as the Daiquiri deposits are concerned, this gap has been filled by the appearance of the two papers by Prof. James F. Kemp2 and by Prof. Waldemar Lind-gren and Clyde P. Ross respectively.3 Max Roesler, first holder of the Emmons fellowship, made a detailed study of the Firmeza deposits during the past summer, so that soon we can expect a full description of them. Consequently, there is no, demand at the present time for a description of the deposits from other sources, and that is not the purpose of this paper. The papers on Daiquiri, however, leave unsolved problems in regard to the age of the rocks of the district and certain phases of the genesis of the deposits, and it is with the hope of aiding in the solution of some of these problems that this contribution is offered. Kemp, and Lindgren and Ross agree in assigning these deposits to the type of contact metamorphic deposits. They disagree in part on the question of their localization. The deposits occur in an extensive area of diorite which includes numerous blocks of limestone, and sometimes are found in the contact zones between these blocks and the diorite, and in other instances are completely enveloped in the diorite, showing no apparent connection with the limestone. The latter class includes

Jan 1, 1916

By Charles Albert Ashburner

THE stratigraphical geology of the vicinity of Buffalo has always been of great interest on account of its bearing on the origin and history of the Niagara-river gorge, between the Falls and Lake Ontario. Recently, however, the character and thickness of the strata which underlie Buffalo have acquired more practical and economic importance on account of their relation to the possible occurrence of natural gas in commercial quantity near the Niagara river. In a paper presented at the Duluth meeting (l887), on " Petroleum and Natural Gas in New york State" (Trans., xvi., 906), I gave a brief description of the four wells which had been drilled by the Buffalo Cement Company between 1883 and that time. One of these wells is 1305 fret deep; and, at the time that my paper was finally revised for the Transactions (June, 1888), it was still an open question whether the drill in this well had reached the Niagara limestone, or had penetrated the Medina sandstones and shales, which latter are boldly exposed in a number of localities in the district, hut more particularly along the Niagara river in the vicinity of Lewiston and Qneenstown. The difficulty in this geological question at Buffalo has lain in the fact that no reliable determination could be made of the thickness of the strata included between the Corniferous limestone, immediately below which the drilling of the Buffalo gas-wells was commenced, and the Niagara limestone. On the other hand, the strata included between the latter limestone and the middle portion of the Medina sandstones and shales, have been minutely measured and studied in the Niagara gorge below the Falls by many American and European geologists. The first reliable section of these strata was constructed by Professor Eaton, and published in 1824 in his report on the Geological and Agricultural Survey of the District adjoining the Erie Canal. This section, extending from Lake Erie to Lewiston, is complete, with the exception that no thickness is given to the Salina or Onoudaga salt group,

Jan 1, 1889

By ARTHUR S. DWIGH

Discussion of the paper of W. W. NORTON, presented at the Salt Lake meeting, August, 1914, and printed in Bulletin No. 92, August., 1914, pp. 1993 to 1999. ARTHUR S. DWIGHT, New York, N. Y.-Mr. Norton's chief argument is directed against the idea that the D. & L. sinter is any better material for the blast furnace than the H. & H. product. He supports this by citing two experimental furnace runs. Reducibility.-To discuss a furnace record like that quoted by Mr. Norton for the five days' run in August, 1912, is manifestly difficult for an outsider, but a possible explanation for the poor reduction on Furnace No. 5, smelting D. & L. sinter, may lie in the fact that both sets of furnaces carried the same fuel charges. Other things being equal, if 11 ½ per cent. coke was right for the furnaces smelting H. & H. product, it Was too much for the furnace smelting D. & L. product, as I shall endeavor to show later, and incipient overfire, accompanied by higher leads in slag and matte, was induced. It may sound like a paradox to say that excessive fuel sometimes produces poor reduction, but it is a sad fact. In certain plants where practically the entire charge to the blast furnaces receives a preliminary treatment by being sintered on the D. & L. machines the peculiarities of this problem have had to be very carefully studied, for serious metallurgical difficulties presented themselves when the change was first made to D. & L. sinter in large quantities. Some of these plants had blast pots before they had D. & L. machines, and many opportunities were afforded for comparative study of this very point. There is reason to believe that, clue to the long period of blowing and the higher temperatures developed in the pots from greater mass action, the iron in the H. & H. product is present chiefly as Fe203, perhaps in the form of ferrites, while in the D. & L. product the iron is present as FeO. The fuel charge in the blast furnace must be so proportioned as to exactly meet the chemical and thermic requirements of reduction and melting. If ally of these functions have been performed before the material enters the furnace, a corresponding allowance should be made or the fuel balance will be disturbed and bad work will result. One of the functions of the coke is to reduce enough metallic Fe for the matte requirements, leaving the remainder of the iron as FeO to go into the slag. In smelting almost any other material than D. & L. sinter the iron must-be reduced from the higher oxides, Fe203 or Fe304, to the protoxide, FeO, before a true comparative basis is reached. Experience has shown that with about one-half D. & L. sinter on the charge the coke should-be cut about 10 per cent. This theoretical benefit is borne out by the practical blast-furnace results on a large scale in numerous plants. In fact, wherever this very important factor is ignored the evil symptoms of excessive fuel will be indicated,

Jan 11, 1914

By Neil Johnson

IN the cyanidation of gold, silver and mixed ores, the solids suspended in the pulp after fine grinding, primary settling and series agitation are subjected to a washing step known, generally, as countercurrent decanta-tion, abbreviated C.C.D. The conventional C.C.D. plant consists of a series of separate thickeners-three to five in number-arranged in series on slightly different elevations. Solids settled in the first thickener are pumped at maximum density into the second thickener, where they are diluted with weak solution overflowing the third. After settling in the second thickener they are pumped to the third, where the process of repulping with still weaker solution is repeated, and so on throughout the system, until they reach the last thickener and are repulped with barren solution or water. Recently there has been developed a new type of thickener, known as the Dorr Washing Tray Thickener, consisting of up to five individual thickeners, which performs in a single unit all the functions of a conven-tional C.C.D. plant. Fig. 1 illustrates the essential features. It is a multicompartment tray thickener, in which the trays operate in series instead of in parallel for countercurrent washing. Feed enters the top compartment via a central, semisubmerged feed well. Strong solution overflows into a peripheral launder. Solids settle to the bottom, are raked to the center and flow into the top of the second compartment, directly below, via an inverted cup and seal. Solids pass downward, compartment by compartment, against a counter flow of wash solution and finally of fresh water. Thus, in accord-ance with the basic C.C.D. principle, the solids transfer the dissolved metal content to the wash solution and finally are removed by a dia-phragm pump from the bottom compartment virtually free of valuable material. Similarly, the wash water, as it flows through the system, becomes increasingly enriched in dissolved metal until it overflows from compartment two and returns to the process.

Jan 1, 1939

By Robert Stefanko

Roof bolting in coal mines has progressed very rapidly in the last decade, and today this method of support is in general use. There are many theories concerning the functions of roof bolts, but the importance of beam building is indisputable. Proper tension in the bolts minimizes shearing along bedding planes and creates a thick, competent beam from individually weak layers. Bolting must be accomplished immediately upon exposure of the roof, and bolt tension must be maintained if roof failure is to be prevented. Seams are being mined today with roof bolt support where conventional timbering was not effective1. The widespread use of continuous mining equipment was made possible by roof bolts which permit long supported spans free of obstructions.2 Since adequate anchorage is the key to successful bolting, better methods for determining the efficiency of anchorage are continually being sought. Attempts have been made to measure bolt loads, thus assessing anchorage efficiency by employing sensing devices between the bolt head and roof. 3,4,5 None of the techniques appears to be very accurate, and all have at least one serious deficiency.

Jan 5, 1962

By H. M. Chance

Stretching from New York southwestwardly to Georgia is a great range of hills and mountains consisting of pre-Palæozoic schists, slates, .and gneissic and granitoid rocks, known locally by many different names; in Pennsylvania as the South mountains, the Berkshire or Durham and Reading hills, and in Virginia and farther south as the Blue ridge. To the northwest of this range lies the " Great Valley," underlain by Lower Silurian limestones, and known as the Lehigh valley, Cumberland valley, Shenandoah valley, valley of Eastern Tennessee and Georgia and by other local names, but all these are parts of one valley, geologically and geographically continuous from New Jersey to Georgia. Lying upon and along the northern flank of this range of mountains, and dipping northwestwardly under the limestone of the valley, is the Potsdam formation (Primal or No. 1 of the Pennsylvania Geological Survey), which consists of sandstone or conglomerate overlain by slates. The latter are sometimes arenaceous and occasionally are replaced in part by sandstone. This formation varies from a few feet to several hundred feet in thickness. At the outcrop the slates are completely decomposed, oxidized or disintegrated, forming a belt of clay several hundred feet wide occupying the interval between the outcroppings of the sandstone and limestone. This clay-belt includes a more or less continuous series of iron-ore (brown hematite) deposite, which have been, and still are, extensively worked. The belt is more or less continuously milleralized with iron throughout its length, and hundreds of large deposits of ore have been developed and worked, producing many millions of tons of ore.

Jan 1, 1909

By A. J. Chellew, Robert Condit

THE Company maintains a port agency at Antofagasta for dispatching copper and also for receiving from ocean vessels the vast variety of materials and supplies required at the plant. Copper shipments from the oxide plant refinery to Antofagasta amounted to 162,000 metric tons during 1951, while incoming freight totalled 175,000 metric tons. Electrolytic market copper in various shapes is currently loaded at the plant upon 20 or 30-ton cars of the meter-gage Antofagasta-Bolivia Railroad, to be transported a distance of 165 miles to the company's yard at Antofagasta. Here it is unloaded by cranes at the rate of about 175 tons per hr. Copper not scheduled for immediate shipment is stocked in tiers within the yard, but most of it is reloaded and sent to port works or a wharf serving lighters. Some of the vessels entering Antofagasta tie up at the port works, while others anchor inside the breakwater. In the latter case, all of the loading into the hatches is from 50-ton lighters towed to the vessel. When the vessel is at the dock, about half of the copper is loaded by port works cranes and the other half is loaded by ship's tackle from lighters. Fuel Oil Requirement Expands One of the innovations caused by the construction of the sulphide plant has been the necessity to provide facilities at Antofagasta for receiving and storing greater quantities of fuel oil than in recent years. From here it is loaded into tank cars for transportation to Chuquicamata. The older installation consisted of a 10-in. submarine pipe line, heating, and pumping facilities, a 67,500-bbl storage tank, and railroad loading rack, located at Antofagasta's northern limits. Two new tanks, of 80,000 and 30,000-bbl capacity respectively, have now been added and a second submarine pipe line will shortly be installed. Fuel oil requirements for the sulphide plant are estimated at 39,000 bbl per month, in addition to which 9000 bbl per month are required for the operation of the oxide plant. The company has a special lighter which is used by its diver for connecting the oil line with the oil tanker when disembarking oil, this lighter also being used for inspecting and overhauling buoys, as well as for recovery of bars of copper which are sometimes dropped into the bay when loading vessels during periods of rough weather. Transport of oil to Chuquicamata is by 76 tank cars of, 20-ton capacity and 20 of 30-ton capacity, all assigned to the company's fuel oil shipments excepting six for Diesel oil and one for gasoline. Incoming Freight Other freight received by the port agency has been averaging about 4800 metric tons per month of operating supplies for the oxide plant (renewals of equipment, spare parts, lubricating oils, and greases, etc.), some 1900 metric tons per month for the company stores, and about 6000 metric tons per month of materials and equipment for the construction of the sulphide plant. The greater part of these shipments (particularly the operating and construction supplies) originate from abroad, and must be handled through the Chilean Customs. Hence the company maintains a Customs storage warehouse (goods pending appraisal of Customs duties) in addition to its other storage facilities at Antofagasta. Not the least of the Port Agency's duties is to meet air and steamer passengers en route to Chuquicamata and to arrange for their trips up the hill. Landing in a strange country with a strange language, the first impressions of a new employee might otherwise be indeed confusing when facing Antofagasta's unique setting of brown barren hills.

Jan 1, 1952

By Thomas Haight Leggett

I.—The Deep-Level Shafts. The gold-deposits of the Witwatersrand (Anglice, " White Waters' Range ") are, as is well-known, more or less parallel and tilted sedimentary beds of quartz-pebble conglomerate impregnated with gold. These beds, however, are locally called "reefs"—a term equivalent in signification to the American "ledge"—and, like the latter, usually applied to lodes, though covering in practical usage all deposits of tabular form. The first developments of the reefs of the Rand were naturally made along their outcrops. Since the mining law of the Transvaal does not confer upon locators the "extralateral right," the property of each locator upon the outcrop or apex ends with the vertical planes drawn through the boundaries of the claim. Consequently those portions of the reefs which lie "on the dip," beyond these boundaries, are separately acquired by locating new surface-claims, and are usually to be mined only by means of vertical shafts, reaching the reefs at considerable depths. The term "deep-level properties " is given to such claims on the dip, and the " deep-level shafts " are the vertical shafts sunk in the hanging-wall of the Witwatersrand reefs, in contradistinction to the incline-shafts almost universally employed on the outcrop-properties. Number and Distribution.—The accompanying diagram, Plate I., shows the number and depth of these deeplevel shafts, completed or under process of sinking, up to January 1, 1900. A number of shafts already located upon new deep-level properties, but upon which no work has yet been done, are not included in this diagram.* Vertical shafts sunk upon outcrop-

Jan 1, 1901

By Howard N. Eavenson

ALL of the matters so far taken up by the Institute Committee on Stabilization of the Coal Industry will be of help, but it seems to be that under present conditions not very much can be expected until the railroad situation has been improved. As an instance of this, I would cite the fact of our experience at our mines in West Virginia and Kentucky. During 1917 and 1918 at our West Virginia plants we produced for our own consumption, practically entirely in the Chicago district, about 4,750,000 net tons of coal. In 1919 our output was reduced to 3,500,000 tons, this being caused partly by the shortage of orders in the few months following the armistice, but more particularly by The car shortage which began last September and continued throughout the remainder of the year, with the exception of December. This car shortage has been more acute since the first of the year, and while we now have an actual capacity here of 20,000 tons daily and have the equipment to produce it, with the possible exception of a few houses, we are able to average only about 12,000 tons, and in consequence, about 30 per cent. of our by-product ovens in the Chicago district are idle, and a number of blast furnaces are down for the want of coke. These figures, of course, refer to conditions before the strike of switchmen in April was started.

Jan 1, 1920

By J. R. Hillebrand

From the abstract, "A realistic ore deposition model to serve as a conceptual framework." Further, on page 246, "The first area of study was the Josephine peridotite, now identified as an ophiolite terrane, located in northern California and southwestern Oregon (Fig. 3). Here, it was felt that we could test the models shown in Figs. 1 and 2 and, if successful, expand the model and test it in other chromite districts in the US and around the world." My comments refer only to chromite deposits in Europe and the Middle East. First, I question that may chromite deposits occur in the idealized ophiolite section shown in [Fig. 1]. Second, although some podiform deposits (referring to morphology) have been important (Gulernan, Turkey, for example), the stratiform deposits are of greater importance in tonnage and frequently grade. Examples include Nada, Yugoslavia; Bulqiza, Albania; Xerolivado, Greece; Saranovsk, Russia; and Abdasht, Iran.

Jan 1, 1984

By G. W. Mao, A. M. Gaudin, D. W. Fuerstenau

Activation of sphalerite with copper salts has long been thought of as a chemical reaction of the following form: ZnS + Cu++ [=] CuS + Zn++ [ 1 ] Early experimentation1-3 showed that the reaction seemed to be stopped by the coating of insoluble copper sulfide, but since the analytical methods were crude, it was only surmised that the reaction could proceed by diffusion. Probably the most conclusive evidence for reaction (Eq. 1) was obtained by Cooke,4 who found a stoichiometric replacement of Zn++ by Cu" after 50 days' reaction at about 100°C. Cooke also found the sphalerite to be covered with a rather thick coating of covellite, which in¬dicates that activation is a continuing replacement of Zn++ by Cu" rather than diffusion of Cu" throughout the sphalerite lattice. However, the occurrence of diffusion at high temperatures has been observed.5,6

Jan 4, 1959