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By Frederic Benard

Recovery of selenium and tellurium at Copper Cliff by the Ontario Refining Co. has been previously described by the writer.l During 1935 a new building was erected to house this operation and description of the new plant and process form the subject of this paper. The building, of modern steel and tile construction, covers an area of 5900 sq. ft. with a volume of approximately 166,000 cu. ft. The large monitored center bay is flanked by two smaller outside bays, one of which is devoted to the tellurium section. All equipment, ceilings and upper walls, are treated with aluminum paint, giving good illumination and facilitating good housekeeping, essential from a health standpoint in handling material of this nature. Equipment Layout and type of equipment conforms to the requirements of the process as described below. In the selenium section, storage tanks, neutralizing tanks and precipitators are of steel construction, lead-lined and arranged for gravity flow (Fig. 1). The neutralizing tanks are equipped with water-cooled lead coils for controlling solution temperature, agitation being accomplished with compressed air. The precipitators are provided with mechanical agitators, and sulphur dioxide is introduced into the solution through 1/2-in. lead pipes leading from a manifold attached to the cover of the precipitator. Each precipitator has internal cooling coils and an air-jet exhauster to carry off fumes. Neutralized solutions are filtered in a 29-plate wooden filter press using heavy cotton duck as a filter medium, forced feed being maintained by a Welmet centrifugal pump. Dilute solutions are concentrated by evaporation in a vacuum evaporator, constructed of cast hard lead. Heat is supplied by an outside steam chest operating under 15 Ib. steam pressure. The solution is circulated through the steam chest by a pump of antimonial lead at a rate approximating 400 cu. ft. per min. The evaporator is evacuated by a water-jet condenser that creates a vacuum of 26 in. of mercury under normal operating conditions. The capacity of the vessel is 60 cu. ft. and the rate of evaporation 25 cu. ft. per hour.

Jan 1, 1943

By Frederic Benard

Recovery of selenium and tellurium at Copper Cliff by the Ontario Refining Co. has been previously described by the writer.l During 1935 a new building was erected to house this operation and description of the new plant and process form the subject of this paper. The building, of modern steel and tile construction, covers an area of 5900 sq. ft. with a volume of approximately 166,000 cu. ft. The large monitored center bay is flanked by two smaller outside bays, one of which is devoted to the tellurium section. All equipment, ceilings and upper walls, are treated with aluminum paint, giving good illumination and facilitating good housekeeping, essential from a health standpoint in handling material of this nature. Equipment Layout and type of equipment conforms to the requirements of the process as described below. In the selenium section, storage tanks, neutralizing tanks and precipitators are of steel construction, lead-lined and arranged for gravity flow (Fig. 1). The neutralizing tanks are equipped with water-cooled lead coils for controlling solution temperature, agitation being accomplished with compressed air. The precipitators are provided with mechanical agitators, and sulphur dioxide is introduced into the solution through 1/2-in. lead pipes leading from a manifold attached to the cover of the precipitator. Each precipitator has internal cooling coils and an air-jet exhauster to carry off fumes. Neutralized solutions are filtered in a 29-plate wooden filter press using heavy cotton duck as a filter medium, forced feed being maintained by a Welmet centrifugal pump. Dilute solutions are concentrated by evaporation in a vacuum evaporator, constructed of cast hard lead. Heat is supplied by an outside steam chest operating under 15 Ib. steam pressure. The solution is circulated through the steam chest by a pump of antimonial lead at a rate approximating 400 cu. ft. per min. The evaporator is evacuated by a water-jet condenser that creates a vacuum of 26 in. of mercury under normal operating conditions. The capacity of the vessel is 60 cu. ft. and the rate of evaporation 25 cu. ft. per hour.

Jan 1, 1943

By P. A. Beck, L. J. Demer

As reported in a previous publication,' isothermal grain growth in high purity aluminum and in an aluminum alloy with 2 pct magnesium can be adequately described by means of the empirical relation: Here, D is the average gain size after an annealing period 1. The annealing period includes the time for complete recrystal-lization R, and the time for gain growth 1,. D, is the pain size as recrystallized, n is a parameter depending on the temperature and on the material. The effect of 2 pet magnesium in solid solution was to decrease D, and to increase R, A and n at a given temperature. The present work was undertaken in order to investigate the above listed-effects of magnesium in solid solution, as functions of the magnesium content. The work also includes the study of certain anomalous effects observed in the recrystal-lization and grain growth of the 2 pct magnesium alloy at 350°C. Experimental Procedure The method of producing the ingots used in this work was described in detail1 and need not be reproduced here. The materials used were high purity aluminum, furnished by the Aluminum Co. of America, of lot analysis shown in Table r and magnesium from a high purity distilled stock of magnesium crystals. Table i—Lot Analysis of High Purity Aluminum Per CeNt Si.................................... 0.00~ Fe.................................... 0.002 Cu................................... 0.002 Mg................................... 0.003 Mn................................... o. oox Ingots were prepared for a series of binary aluminum-magnesium alloys of increasing alloy content. The numbers used to designate these ingots and their magnesium contents by chemical analysis are given in Table 2. Table 2—Ingot Numbers and Magnesium Contents Ingot Number Pct oa Magnesium aI 2.05 22 1.80 24 0.12 26 0 02s The analyses showed no difference in composition between the top and the bottom of the ingots. Spectrographic analysis of the ingots for elements other than magnesium showed, within the limits of accuracy of the method, no increase in impurities over the amounts given in the lot analysis for the high purity aluminum in Table I. Careful microscopic study of ingot 21 in the as-cast condition, at magnifications up to I 500X, revealed a cer-

Jan 1, 1949

By Frederic Benard

RECOVERY of selenium and tellurium at Copper Cliff by the Ontario Refining Co. has been previously described by the writer.1 During 1935 a new building was erected to house this operation and description of the new plant and process form the subject of this paper. The building, of modern steel and tile construction, covers an area of 5900 sq. ft. with a volume of approximately 165,000 cu. ft. The large monitored center bay is flanked by two smaller outside bays, one of which is devoted to the tellurium section. All equipment, ceilings and upper walls, are treated with aluminum paint, giving good illumination and facilitating good housekeeping, essential from a health standpoint in handling material of this nature. EQUIPMENT Layout and type of equipment conforms to the requirements of the process as described below. In the selenium section, storage tanks, neutralizing tanks and precipitators are of steel construction, lead-lined and. arranged for gravity flow (Fig. 1). The neutralizing tanks are equipped with water-cooled lead coils for controlling solution temperature, agitation being accomplished with compressed air. The precipitators are provided with mechanical agitators, and sulphur dioxide is introduced into the solution through 3-in. lead pipes leading from a manifold attached to the cover of the precipitator. Each precipitator has internal cooling coils and an air-jet exhauster to carry off fumes. Neutralized solutions are filtered in a 29-plate wooden filter press using heavy cotton duck as a filter medium, forced feed being maintained by a Welmet centrifugal pump. Dilute solutions are concentrated by evaporation in a vacuum evaporator, constructed of cast hard lead. Heat is supplied by an outside steam chest operating under 15 lb. steam pressure. The solution is circulated through the steam chest by a pump of antimonial lead at a rate approximating 400 cu. ft. per min. The evaporator is evacuated by a water-jet condenser that creates a vacuum of 26 in. of mercury under normal operating conditions. The capacity of the vessel is 60 cu. ft. and the rate of evaporation 25 cu. ft. per hour.

Jan 1, 1938

Lead-zinc production in Canada accounted for 19% of the total value of metals and minerals produced in 1976, says Keith C. Hendrick, president of Noranda Sides Corp. Mine production of recoverable zinc w as 1. 158 million toils of 27.4% of free world production in 1976. Slab zinc pro¬duction was placed at 472,000 tons that year. Canadian mine production of recoverable lead was 247,000 tons or 10.6% of the free world production. Refined lead that year was at 177,000 tons.

Jan 11, 1977

By Wilbur E. Sanders

AT some period during the operation of metalliferous and other commercially valuable mineral-deposits in connection with their underground mining, when the developments therein have become so extensive that their description is tedious and confusing, some scheme for naming or numbering the various workings and their parts is necessary for convenience of ; reference.. A simple and symmetrical yet expansive system of classification must be devised, one that is capable of being extended to cover all possible exigencies and conditions of future operations within the property. Such a scheme, properly arranged, greatly simplifies communication between the various departments of the mining business, as, for instance, between the administrative and the operating departments of the concern, and is of the greatest assistance to the officers of the mine in enabling them to locate and describe particular points and parts of workings and specific kinds of work. Again, in the proper segregation and differentiation of mine-accounts, when they are carried out with that detail which will furnish ready information concerning the cost of a particular piece of work, or the various items and totals of expense connected with the, development,, operation and repair of each or all of the mine-workings, some such method of designation becomes a necessity. . Moreover, such a plan is admirably adapted to the needs of the mining engineer, who, in connection with his reports upon mining-properties, is sometimes required, in his descriptions of certain blocks of ore, to locate lists of assays of samples taken from many and various places, and to designate workings and parts of workings that are located in different parts of the mine, sometimes at points wide apart.

May 1, 1906

By Clinton H. Crane

DR. TILNEY, the great expert on the study of the development of the brain of human beings and animals, tells us that the greatest difference between the human brain and the brain of animals is that man alone has shown evidence of being able to predict the future. Just why he throws overboard the busy bee who lays up honey for the winter, the squirrel who gathers nuts, and the humble ant, I do not know. At any rate, it is nice to be assured by an authority that we have this power of prophecy. My own experience with attempting to prophesy the future has convinced me that our only possibility of being good prophets is to be good students of history.

Jan 1, 1940

By Victor L. Stevens

The Oso tunnel is one of three tunnels located on the San Juan-Chama Project in south-central Colorado. The purpose of the tunnel is to carry water from the upper San Juan watershed through the Continental Divide into the Rio Grande watershed. The Oso tunnel contract was awarded by the U.S. Bureau of Reclamation to a joint venture of Boyles Brothers Drilling Co., Gibbons & Reed Co., and Cimco in February 1966. The Oso tunnel is 26,660 ft long and has a rock section of 10 ft, 2 in. with a lined diameter of 8 ft circular. The main portion of the rock formation was in the Lewis shale. This formation is quite consistent in hardness and texture with exception of localized limestone concretions and sandy siltstone inclusions. The job was bid on the basis of using a James S. Robbins mole of the P221 series. The decision for using a mole was predicated on the geology and the experience of the same joint venture on the adjoining Azotea tunnel where a mole was successfully used. The Robbins P221 series mole is capable of cutting from 9 ft, 11 in. to a 10 ft, 7 in. diam without any major change. It is 40 ft long and weighs 60 tons. The cutting head has 22 disk-type cutters and one center pilot (standard 9 7/8 -in.) tricone bit. The head is powered by four 75 hp electric motors. Gripper pads at about the midway point on each side of the machine are pushed into the tunnel ribs and thrust-cylinders in front of each gripper apply pressure to the face as the head rotates. The regripping cycle is 3 ft and then the grippers are retracted and advanced. Each cutter on the perimeter of the head is followed by a bucket which scoops up the cut material, almost in the same manner as a water wheel, and dumps it into a conveyor situated along the top of the mole. The muck from the mole conveyor is dumped into a gantry-type conveyor. The gantry conveyor is 350 ft long and is pulled

Jan 1, 1970

By J. French Robinson

A review of production in the Eastern District for 1930 is necessarily brief. Drilling operations were curtailed, due to economic conditions, which in turn reduced production. However, in spite of these conditions, there have been a few outstanding developments which surpass any of recent years. The development of a field in Chautauqua and Cattaraugus counties, New York, has been rapid and probably reached its peak of production in 1930. The gas in this field comes from the White Medina Sand (Silurian), at an average depth of 2600 ft. Some of the wells had an open flow of 20,000,000 cu. ft. of gas per day,' with an original rock pressure of 965 pounds2 per square inch. Another area developed during 1930 was the Tyrone field, in Tyrone Township, Schuyler County, New York. This field was discovered 2nd is practically controlled by the Belmont Quadrangle Drilling Corpn. of New York. The production is from the Oriskany Sand (Devonian), which is found at an average depth of 2100 ft. The field covers approximately 2000 acres, and to date has 14 producing gas wells. The largest well had an open flow of 15,000,000 cu. ft. and an original rock pressure of 740 Ib. The gas from this field is impregnated with sulfur, and requires washing before it is marketed. Because little is known of the Oriskany Sand, a brief description may be of interest. This sand outcrops at Oriskany Falls, New York, and has a thickness of 10 to 12 ft. Its texture is coarse grained, it is composed mostly of quartz and is a regularly bedded sandstone. At Yauger's Wood, in Cayuga County, New York, it is exposed and shows a thickness of 26 feet. The discovery of the Tyrone field led to much prospecting in the New York and the northern part of Pennsylvania, and as a result of this search, the Allegany Gas Co. struck a large gas well in Farmington Township, Tioga County, Pennsylvania, which created considerable excitement through the Eastern District. The gas was encountered at a depth of 4010 ft., and tested 20,000,000 cu. ft. open flow, with a shut-in pressure

Jan 1, 1931

By David Keys

THE object of this investigation was to determine with a vertical magnetic variometer the extent of the titaniferous ore deposit that occurs not far from Ivry in Terrebonne County, Quebec, about 70 miles north of Montreal. The Ivry mine, on lots 37 and 38 of range V, Beres-ford township, Quebec, is one of the largest and most accessible to transportation of the deposits of ilmenite in Quebec. The ore consists of an aggregate of ilmenite anhedra serving as host for numerous fine plaques of hematite. No magnetite is known from any occurrence near this lot, and in this way the deposit differs from many others that contain a large percentage of magnetite with the ilmenite. The deposit at Ivry thus has much lower magnetic susceptibility than those containing abun-dant magnetite, and a sensitive magnetometer was necessary for the work, although a body of magnetite with ilmenite about a mile from the Ivry mine was successfully prospected with a dip needle. The principal orebody is exposed in a quarry known as the Ivry mine, from which about 16,000 tons of ore have been shipped. Small exposures of ilmenite isolated by drift serve to show the presence at the surface of some of the bodies indicated by the magnetometer,- but most of the hill is covered with glacial till and second growth hardwood. At the lower levels the till gives place to fluvioglacial sands and gravels from which the forest has been cleared. The increasing thickness of the sand and gravel as the hill descends makes the tracing outward of the deposits from the rocky knob of anorthosite a difficult matter. Within the orebodies too, some masses of anorthosite persist, which may account for some local irregularities. Fig. 1 is a photomicrograph, taken by reflected light, of a typical specimen of the ore. The dark patches are hematite and the light parts are ilmenite. No trace of magnetite was found. Fig. 2 is a photo-micrograph of a thin section of the country rock showing the texture of the anorthosite. The mean of four analyses quoted by Robinson1 is: titanium, 19.26 per cent; iron 45:41 per cent.

Jan 1, 1936

By Robert C. Stephenson

Large deposits of titaniferous magnetite occur associated with anorthosite and gabbro in the Lake Sanford area, Essex County, New York. The ore, gabbro, and anortbosite show consanguineous relations. Anorthosite grades through gabbroic anortbosite into gabbro but is locally intruded by gabbro. Structural and petrographic evidence suggests that gabbro was differentiated from anorthosite by filter pressing. Field and laboratory study of ore occurrences indicates that an ore residuum concentrated in the gabbro through magmatic segregation' by normal crystallization and flowage. Ore occurs as bands which grade into gabbro, and also as large masses which replace anorthosite. Ore in the gabbro is finer grained and richer in ilmenite than ore in anorthosite. Introduction The Lake Sanford area lies in the heart of the Adirondack Mountains, in the southeast portion of the Santanoni Quadrangle (Fig. I), and there are four ore bodies in the area immediately surrounding Lake Sanford. The area lies 30 miles by highway from the railroad at North Creek. The deposits were discovered in 1826, and from then until 1858 iron was produced in small quantities. They were idle from 1858 to 1906. Between 1906 and 1913, extensive development work was carried on. These early attempts to produce iron ore were thwarted by transportation difficulties and by the titanium content of the ore, which, ironically, has been the element responsible for the present development. In 1941 the National Lead Co., Titanium Division, developed the Sanford Hill ore body and is now producing ilmenite and magnetite concentrates.18 The Defense Plant Corporation is extending the railroad to the property from North Creek and is building a sintering plant to treat the magnetite concentrate. Investigations OF the Deposits* Early studies of the Lake Sanford titaniferous magnetite deposits were made by Emmons in 1842,l2 by Kemp, in 1897-98'0 and by Newland in 1908.22 Singewald26 and Osborne23 considered these deposits along with numerous other titaniferous magnetite deposits in 1913 and 1928, respectively. None of these reports entailed a detailed study of the ore occurrence in this area. The present study was begun in 1940. Seven months were spent in the field, and considerable time was spent in labora-

Jan 1, 1949

CONTENTS PAGE MERRISS, M. H.-Direct Electrolysis of Black-copper Anodes of High Nickel-lead Content. Discussed by C. S. Witherell, C. P. Linville, G. E. Dalbey, M. H. Merriss 1 GRISWOLD, GEORGE G.-Calculating the Zinc for Desilverizing Lead Bullion by the Parkes Process. Discussed by C. S. Witherell, George G. Griswold, Milo W. Krejci, Lawrence Addicks, W. F. Gross, H. H. Alexander, A. F. Beasley, C. P. Linville 3 ALEXANDER, H. H. and STACK, J. R.-The Reduction and Refining of Tin in the United States. Discussed by Edward F. Kern, J. R.' Stack, R. L. Hallett, C. R. Hayward, William H. Bassett, R. C. Canby, H. G. S. Anderson 20 GREENAWALT, WILLIAM E.-Greenawalt Electrolytic Copper Extraction Process. Discussed by Stuart Croasdale, Colin G. Fink, Arthur L. Walker, Edward F. Kern, Henry A. Tobelmann, Oliver C. Ralston 26 BENEDICT, C. H. and KENNY, H. C.-Ammonia Leaching of Calumet and Hecla Tailings. Discussed by G. E. Dalbey, C. H. Benedict 34 RALSTON, OLIVER C.-Hydrometallurgy of Lead. Discussed by F. L. Bosqui, Jr., George D. Van Arsdale 34 TAINTON, U. C. and LEYSON, L. T.-Electrolytic Zinc from Complex Ores. Dis¬cussed by W. G. Woolf, C. A. Hansen 39 Direct Electrolysis of Black-copper Anodes of High Nickel-lead Content Discussion of the paper of M. H. MERRISS, presented; at the New York Meeting; February, 1924, and, issued, as Paper No. 1273-M, with MINING AND METALLURGY, September, 1923. C. S. WITHERELL, New- York, N. Y. (written discussion).-This paper is particularly valuable in that it gives the results of operations -carried out under conditions differing from standard practice. In the electrolytic refining of copper, as in other kinds of metal refining, it is occasionally necessary to treat extraordinary foul or complex material, in which cases 'it is valuable to know what other metallurgists have accomplished under similar conditions. As tapping the slimes-covered anodes brought the tank-voltage down to 0.45 to 0.50 volt, the counter electromotive force was, probably not more than 0.1 or 0.2 volt; hence the so-called polarization was, mainly,

Jan 6, 1924

By Robert C. Stephenson

Large deposits of titaniferous magnetite occur associated with anorthosite and gabbro in the Lake Sanford area, Essex County, New York. The ore, gabbro, and anortbosite show consanguineous relations. Anorthosite grades through gabbroic anortbosite into gabbro but is locally intruded by gabbro. Structural and petrographic evidence suggests that gabbro was differentiated from anorthosite by filter pressing. Field and laboratory study of ore occurrences indicates that an ore residuum concentrated in the gabbro through magmatic segregation' by normal crystallization and flowage. Ore occurs as bands which grade into gabbro, and also as large masses which replace anorthosite. Ore in the gabbro is finer grained and richer in ilmenite than ore in anorthosite. Introduction The Lake Sanford area lies in the heart of the Adirondack Mountains, in the southeast portion of the Santanoni Quadrangle (Fig. I), and there are four ore bodies in the area immediately surrounding Lake Sanford. The area lies 30 miles by highway from the railroad at North Creek. The deposits were discovered in 1826, and from then until 1858 iron was produced in small quantities. They were idle from 1858 to 1906. Between 1906 and 1913, extensive development work was carried on. These early attempts to produce iron ore were thwarted by transportation difficulties and by the titanium content of the ore, which, ironically, has been the element responsible for the present development. In 1941 the National Lead Co., Titanium Division, developed the Sanford Hill ore body and is now producing ilmenite and magnetite concentrates.18 The Defense Plant Corporation is extending the railroad to the property from North Creek and is building a sintering plant to treat the magnetite concentrate. Investigations OF the Deposits* Early studies of the Lake Sanford titaniferous magnetite deposits were made by Emmons in 1842,l2 by Kemp, in 1897-98'0 and by Newland in 1908.22 Singewald26 and Osborne23 considered these deposits along with numerous other titaniferous magnetite deposits in 1913 and 1928, respectively. None of these reports entailed a detailed study of the ore occurrence in this area. The present study was begun in 1940. Seven months were spent in the field, and considerable time was spent in labora-

Jan 1, 1949

By Maurice L. Pinel, Thomas T. Read, Thomas A. Wright

THE erroneous, but until recently widely prevalent, belief that iron castings were first made in Europe in the fourteenth century has been adequately refuted in a number of earlier papers;1,11,12 but except for an unpublished metallographic study by the late William Campbell, and a phosphorus analysis by T. A. Wright of the metal of the Han dynasty cast-iron stove described by Laufer,2 nothing was known of either the chemical composition or the metallographic structure of the metal of any ancient iron casting, although data on castings of recent manufacture are abundantly available. The metal of the stove, which had been buried in a grave for at least 15 centuries, was so corroded that it seemed inadvisable to publish the results on it until more and better specimens from other ancient castings could be obtained. During a journey through China, extending from Peking in the north to Canton in the south and Cheng-tu, Ssu-chuan, in the west, in the late summer and autumn of 1936, one of us (T. T. Read) was fortunate enough to obtain, and bring home for study, nine castings, all more than 1000 years old, of which the date of manufacture is precisely known because of inscriptions cast in them, another that lacks a dated inscription, but of which the date, as explained below, can be otherwise established, and a specimen from the largest iron casting ever made," which is also dated. The period covered by this suite of specimens extends from 502 to 1093 A.D. In addition, a sample was obtained from a casting of date unknown, but which was certainly cast before 1000 A.D. and possibly as early as the third century A.D. A detailed description of these specimens is as follows: 1. 502 A.D. A pair (right and left) of recumbent lions (Fig. 1). Base 7 ¼ by 14 3/8 in., height over-all 5 ½ in., weight 26 lb. each. The translation of the inscription on the base is: "Made on the twenty-fourth day of the seventh month of the third year of Ching Ming of Great Wei" (Sept. 11, 502 A.D.).

Jan 1, 1938

By E. R. Parker, R. H. Thielemann

The conventional short-time tensile test provides a reliable means of predicting the sustained load-carrying capacity of steels only when the temperature is such that continuous plastic flow does not occur. At elevated temperatures, stresses considerably less than the short-time rupture value may produce continuous flow, with fracture occurring only after long periods of time. The amount of flow or creep accompanying failure varies for different steels, and depends, to a large extent, on the temperature and the duration of the test. Service records of cracking stills, steam superheaters and high-temperature boilers have shown that brittle fractures sometimes occur with little or no warning. In installations of this type, localized stresses are often encountered, and steels must be capable of withstanding a certain amount of deformation without fracture. The sustained-load rupture test determines the expected life and corresponding ductility of steels at various stresses and temperatures. It also yields additional information regarding the effect of micro-structure and metallurgical stability on the high-temperature properties. Present Status of Sustained-load Rupture Test The sustained-load rupture test conducted at elevated temperatures is not entirely new. Dr. Zay Jeffriesl presented in 1919 the results of a large number of rupture tests made on copper, iron and tungsten. These tests were made with various strain rates and at temperatures ranging from the boiling point of liquid air to 1000° C. At that time he observed the interesting phenomenon characteristic of metals, that a temperature exists below which a metal is ductile and breaks with a transcrystalline fracture (through the grain) and above which the metal is brittle and breaks with an intergranular fracture (through the grain boundaries). He observed that this temperature varied with the testing speed, and that a minimum temperature, slightly above the recrystallization temperature, existed at which the cohesion of the grains themselves was

Jan 1, 1939

By R. H. Thielemann, E. R. Parker

The conventional short-time tensile test provides a reliable means of predicting the sustained load-carrying capacity of steels only when the temperature is such that continuous plastic flow does not occur. At elevated temperatures, stresses considerably less than the short-time rupture value may produce continuous flow, with fracture occurring only after long periods of time. The amount of flow or creep accompanying failure varies for different steels, and depends, to a large extent, on the temperature and the duration of the test. Service records of cracking stills, steam superheaters and high-temperature boilers have shown that brittle fractures sometimes occur with little or no warning. In installations of this type, localized stresses are often encountered, and steels must be capable of withstanding a certain amount of deformation without fracture. The sustained-load rupture test determines the expected life and corresponding ductility of steels at various stresses and temperatures. It also yields additional information regarding the effect of micro-structure and metallurgical stability on the high-temperature properties. Present Status of Sustained-load Rupture Test The sustained-load rupture test conducted at elevated temperatures is not entirely new. Dr. Zay Jeffriesl presented in 1919 the results of a large number of rupture tests made on copper, iron and tungsten. These tests were made with various strain rates and at temperatures ranging from the boiling point of liquid air to 1000° C. At that time he observed the interesting phenomenon characteristic of metals, that a temperature exists below which a metal is ductile and breaks with a transcrystalline fracture (through the grain) and above which the metal is brittle and breaks with an intergranular fracture (through the grain boundaries). He observed that this temperature varied with the testing speed, and that a minimum temperature, slightly above the recrystallization temperature, existed at which the cohesion of the grains themselves was

Jan 1, 1939

By Rclssell Gibson, F. S. Turneaure

The tin deposit of Monserrat; Bolivia, consists of one major vein 1600 m in length. The ore is unusual because of the notable quantity of teallite, even though cassiterite is the principal tin mineral. The deposit, formed at shallow depth under a wide range in temperature, may be classed as xenothermal. Polished sections reveal a complex history of replacement, with low-temperature minerals deposited before high-temperature minerals.

Jan 1, 1950

By Manning W. Cox

Van Stone mine area is situated at the head of Onion Creek on the northwest flank of Gillette Mountain, Stevens County, Washington. The di strict was found during World War I, but the mine did not come into production until 1952. Production to the end of 1965 was 2,242,960 tons of ore that yielded 10,700 tons of lead concentrates and 120,000 tons of zinc concentrates. The area is part of the Selkirk Mountains Zinc-Lead Belt, or Kootenay Arc, extending from near Revelstoke, British Columbia, to Colville, Washington. A thick but incomplete section of Paleozoic marine formations occurs in the Kootenay Arc and is overlain by marine and continental Mesozoic formations. Both are invaded by Late Mesozoic-Tertiary batholiths. The belt is characterized by open complex folding and extensive high-angle and local thrust faulting. Principal ore deposits occur in the highly deformed carbonate rocks of Cambrian age-the Maitlen (Laib) and Metaline formations. The Van Stone mine occurs along a steeply S-shaped fold lying between the Kaniksu Batholith on the west and the Rogers Mountain Fault, a northeast-trending fault on the west flank of the Gillette Mountain Anticline, to the southeast. The fold is cut by northeasttrending faults containing notoriously irregular lamprophyric, diabasic, and pebble dikes. The host rocks, lower Paleozoic dolomites, are decolorized, silicified, and silicated in the mine area. Jasperoid and tremolite are the common alteration minerals. Other gangue minerals are barite, pyrite, brucite, calcite, and, near the batholith, pyrrhotite. Ore minerals are galena, jamesonite, and sphalerite. Ore minerals occur in bunches and pods intergrown with tremolite and jasperoid. Zinc is roughly eight times more abundant than lead. The highest ore outcrops at 3870 feet elevation, and an undeterminable portion has been removed by glacial scour. The lowest drill hole penetration has reached 3220 feet elevation. Oxidation ranges up to several hundred feet in depth and may be most closely related to pre-glacial groundwater circulation. The area of the mine was completely over-ridden by Pleistocene continental glaciers, and the present erosion surface is nearly continuously blanketed by up to 150 feet of glacial outwash.

Jan 1, 1968

By John Wellington Finch

WHAT is an engineering opportunity? To the mining .engineer the natural assumption is that the first requisite 'is a mineral deposit, but, of course, it is not so simple as that. There are at various points on the earth really very great mineral deposits which, on account of geographic location, backwardness of the country, or hostility of its natives, are now, and for a long time to come will be, quite valueless. The mining engineer, and for that matter the civil engineer, is more dependent upon the decisions of capital than upon any other factor in his profession. Ordinarily it is to be assumed that money will go to any place where it is clear that an adequate return upon its investment can be secured, but for many years it has not been safe to depend upon this. ' As already stated, there are many places where local conditions are such that mining is not safe to engage in and there are still other places in which conditions have been so aggravated by the Great War and by the social unrest which has upset the Asiatic region that capital is naturally most reluctant to venture, even when engineering data makes the undertaking appear attractive. It will be evident, I. believe, that there are many factors vital to the success of a mining enterprise in some of the remote countries which we do not have to consider in the United States and which do not, in fact, exist here.

Jan 1, 1924

By John Wellington Finch

THE- impression which the public has of northern Canada is that it is a' vast wilderness of forests; river's, and. lakes, sparsely inhabited by. a few Indians and `containing a few, scattered trading posts of the Hudson Bay Co. This is far from the facts. The building of the Canadian Pacific Railway led to the discovery, in 1883, of the nickel deposits of Sudbury, Ont.; these are the largest known nickel deposits in the world and produce about 90 per cent. of the world's output of nickel. The building of the Temiskaming and Northern Ontario Railway north, from North Bay, to open up farming lands along Lake. Temiskaming, resulted in the discovery and development of the great silver deposits of the Cobalt area, Ontario. Since the discovery of these deposits in 1903 to Dec. 31, .1923, Cobalt has produced a total of ' 327,301,897 oz. of silver, valued at $212,668,434, and paid in. dividends $88,338,185. In 1923 the production of Cobalt amounted to 10,285,247 oz. of silver. Just south of Cobalt, in South Lorrain,. a. new silver district has recently been developed and mills have started production. These deposits are of such extent that 'a branch railroad is under construction from Cobalt to that area. Northwest of Cobalt is the Gowganda silver area which is also a producer of silver ore and is now attracting outside attention. This area is not connected by railroad.

Jan 1, 1924