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By Roy E. Thomas

Soon after the Waelz p1an.t for the fire concentration of low-grade zinc ores was put into operation in the early part of 1929 at Katowice, it was found that the conveyor equipment for transporting the hot residue from the furnace dust chambers was inadequate. Hand tramming with water cooling was used for a time, but that method was injurious to the workmen as well as costly. The problem was to find some practical mechanical means of conveying flue dust at temperatures of from 450" to 600°C. as it was drawn from the dust chambers. After considerable preliminary investigation it was decided to install pneumatic equipment for conveying the hot materials to a central mixing plant, where it would be mixed with slime and from which it would be returned to the furnace feed hoppers. The first pnenmatic equipment was installed in 1930, and has been in successful operation since that time. The pneumatic method of transportation has shown a considerable saving in operating costs over the former methods of dust handling and a decided improvement in working and hygienic conditions at the plant, through the elimination of the dust hazard. Additional pneumatic equipment mas installed in 1933 for conveying the furnace fume from the baghouses to the roaster plant. At the same time pick-up lines were provided for collecting the cleanings from the vertical and horizontal cooling pipes that are between the furnace dust chambers and the baghouses. The latter installation has practically eliminated a dusty and costly hand-tramming operation. A third extension was made to the pneumatic system in 1938 for conveying 'the zinc-lead-cadmium fume from the roaster-plant baghouses and flues to a new re-treatment plant for secondary products. The success of pneumatic conveying at the Waelz plant was the determining factor in the decision to install another pneumatic unit at the Saeger zinc-roasting and sintering plant. The new unit at Saeger was installed early in 1938 for the transportation of flue and Cottrell dust, small amounts of flotation concentrates to the sinter machines, and

Jan 1, 1944

By Raymond Mancha

The number of installations of propeller mine fans completed during the years of 1936 and 1937 is evidence of the increasing popularity of the propeller fan with the American mining industry. During the period from 1931 to 1936, there were several different low-pressure, low-efficiency propeller fans available, which filled a definite need in replacing inefficient centrifugal fans operated at comparatively low pressure by means of purchased power. Since 1936, however, the trend toward the propeller fan has greatly increased, as propeller fans are now available practically without pressure limitations and capable of efficiencies high enough to warrant replacement of efficient centrifugal fans in many instances. Few manufacturers of propeller mine fans base their fan-operating characteristics upon similar test methods, primarily because of inadequate facilities for testing in the factory and the need of a test code incorporating a calibrated duct or nozzle that makes possible the testing of large propeller fans quickly, accurately and without prohibitive expense and space requirements. As a result, fan manufacturers have resorted to various methods for testing large propeller fans in the factory, and different yardsticks have produced uncomparable and often inaccurate performance data. It is the purpose of this paper to describe and discuss in detail the test procedure of the Jeffrey Manufacturing Co., which has been proved both accurate and practical. Fig. 1 shows a plan, a side elevation and two end elevations of the test duct with a propeller fan of the exhaust type in place. Testing propeller fans exhausting permits greater accuracy than testing these fans blowing, because in the former uniform flow conditions are more easily established at Pitot tube stations where fan pressure and air-volume measurements are desired. Any residual rotation remaining in the air discharged from a propeller fan blowing into a test duct must be removed before an attempt is made to obtain accurate pressure and volume readings. Although various devices for straightening the air may be placed between the blowing fan and the volume-measuring station without resulting complications, uniform flow so obtained at the pressure-measuring station necessitates corrective calculations to compensate for duct resistance

Jan 1, 1940

By Raymond Mancha

The number of installations of propeller mine fans completed during the years of 1936 and 1937 is evidence of the increasing popularity of the propeller fan with the American mining industry. During the period from 1931 to 1936, there were several different low-pressure, low-efficiency propeller fans available, which filled a definite need in replacing inefficient centrifugal fans operated at comparatively low pressure by means of purchased power. Since 1936, however, the trend toward the propeller fan has greatly increased, as propeller fans are now available practically without pressure limitations and capable of efficiencies high enough to warrant replacement of efficient centrifugal fans in many instances. Few manufacturers of propeller mine fans base their fan-operating characteristics upon similar test methods, primarily because of inadequate facilities for testing in the factory and the need of a test code incorporating a calibrated duct or nozzle that makes possible the testing of large propeller fans quickly, accurately and without prohibitive expense and space requirements. As a result, fan manufacturers have resorted to various methods for testing large propeller fans in the factory, and different yardsticks have produced uncomparable and often inaccurate performance data. It is the purpose of this paper to describe and discuss in detail the test procedure of the Jeffrey Manufacturing Co., which has been proved both accurate and practical. Fig. 1 shows a plan, a side elevation and two end elevations of the test duct with a propeller fan of the exhaust type in place. Testing propeller fans exhausting permits greater accuracy than testing these fans blowing, because in the former uniform flow conditions are more easily established at Pitot tube stations where fan pressure and air-volume measurements are desired. Any residual rotation remaining in the air discharged from a propeller fan blowing into a test duct must be removed before an attempt is made to obtain accurate pressure and volume readings. Although various devices for straightening the air may be placed between the blowing fan and the volume-measuring station without resulting complications, uniform flow so obtained at the pressure-measuring station necessitates corrective calculations to compensate for duct resistance

Jan 1, 1940

By F. H. Willcox

In Bessemer-steel practice, air is blown through a bath of iron, or projected strongly upon its surface to burn out silicon, manganese, and cafbon. Toward the end of the blow, when the iron is not protected from oxidation by these elements and the excess of air becomes great, there is oxidation of the iron. In open-hearth practice, the same difficulty is experienced with dissolved gas and oxides in the product, though not to as great or severe a degree as in the Bessemer process because the oxidizing conditions grow less severe as the end of the heat is approached, and if the bath is allowed to boil for a time it undoubtedly frees itself from a large part of the gas and oxides which have been absorbed in the earlier part of the process. Basic open-hearth steel is usually assumed to contain a larger proportion of oxides than acid open-hearth steel, but it may be said that all steel, Besserner and open-hearth, contains more or less oxide of iron dissolved in the fluid metal at the end of the "blow" or "heat." That certain metals are solvents for their respective oxides has been shown, in the case of copper, by Heyn, and, in the case of iron, by Law. It is indicated that the solubility of iron oxide in iron increases with the purity and temperature of the metal. This confirms what is observed and known by operating men, and these observations may be summarized as follows: 1. Cast iron. is rarely subject to oxidation, as is logical from its composition. 2. Normal steel, unless deoxidizers are added, contains blow holes. 3. Steel known to be oxidized is full of blow holes. 4. The addition of deoxidizers prevents, to a greater or less degree, the formation of blow holes in normal steel. With these observations in mind, it is logical to deduce that the cause of blow holes lies in part in the presence of dissolved oxide of iron in the molten steel and its consequent reaction with the carbon of recarburizers, when these are added, to form gases. (Another factor in the origin of blow holes is, of course, the solubility of gases themselves in the steel and

Jan 1, 1917

By F. Julius Fohs

TAKING into consideration the present state of geologic knowledge and present economic status of the oil industry, we have attempted to outline the six principal districts in which oil occurs and new pools may be expected. The map, Fig. 1, also shows the location of the present productive pools-about 100 in number. The unshaded areas represent territory where drilling depths to known sands are prohibitive with present development and pumping methods, or such sands are absent or give promise of such small production that deep wildcat tests are unwarranted. They include, also, territory where the oil-source materials are absent or not of the right type; and where shales are insufficient in the stratigraphic section to prevent the escape of oil and gas. Some doubtful districts are also included, such as the Pecos Valley, where the percentage of rigid beds, sandstones and limestones may be too great; and the Nacogdoches oil field, where small shallow production is obtained but where deep or large production is unlikely. The map is not offered as final but in the hope that it may prevent the expenditure of large sums in attempted development of unlikely territory and as the warning that those who drill in the unshaded territory do so at great risk. Those who drill in such territory should have large sums available for pioneering and experimenting and only attempt it if they can well afford to lose the money expended. Search in the shaded or cross-hatched areas is hazardous enough and should only be undertaken after detailed geologic surveys. Out of a total area of 256,000 sq. mi., the oil and gas districts comprise about 80,000 sq. mi.; the territory embraced in these districts is shown in the shaded portions. This may ultimately be increased somewhat by the addition of some minor districts, but such additions will be offset by territory probably now included in the unshaded areas. The shaded areas probably contain 98 per cent. or more of the ultimate production of the state, despite the fact that they represent only 31 per cent. of the total area.

Jan 3, 1924

By Guido Bassi

IT is known'" that secondary recrystallization occurs in copper sheet with at least 90 pct reduction after annealing at high temperatures, 700" to 1000°C. Turkalo and Turnbull4 have found recently that secondary recrystallization might occur even after annealing at such low temperatures as 500°C for a high purity, coarse-grained copper sheet. It will be shown in the following that in an electrolytic tough pitch copper wire, with a high degree of deformation, secondary recrystallization might occur at even lower temperatures. A hot-rolled rod of 9.5 mm diam (temperature at which rolling commenced was 850°C) was drawn in continuous drawing machines to 0.4 mm, corresponding to a cross-section reduction of 99.8 pct. The texture in the center of the wire (the sample for X-ray analysis was etched to 0.15 mm diam) is a mixture of the [111] and the [loo] direction, as can be seen from Fig. 1. This is in accordance with the result of Schmid and Wassermann.' After a few minutes annealing of the wire at 200 °C, there is a noticeable recrystallization of the structure with a preferred orientation in the [l00] direction at the expense of the [Ill] deformation texture, as Figs. 2 and 3 show. Farnham and OINeill" reported a similar result. The final recrystallized structure shows mainly the [loo] orientation. There is however a small amount of [111] and random orientations. If the wire is annealed at 400°C, the recrystallized structure first shows a [loo] texture, Fig. 4, but as the annealing time is increased the fine-grained structure transforms into coarse grains, Fig. 5, giving a new preferred orientation, Fig. 6. The calculations show this to correspond to the [I121 direction. Even if the annealing that gives the primary recrystallization is carried out for six weeks at 20O°C, the same secondary recrystallization texture is obtained if the annealing is continued at 400°C. Schmid and Wassermann7 found the [I121 texture, but only after annealing at 1000°C or higher. The appearance of a secondary recrystallized

Jan 1, 1952

By M. A. Mosher

Most modern electrolytic copper refineries have found it expedient to build and operate a complete secondaries plant for the treatment of the electrolytic slime accumulated in the cells during the corrosion of the copper anodes. In the earlier years this was done for the sole purpose of promptly recovering in marketable form the silver and gold contained in the slime. Later, improvements in refining methods made possible the recovery of the more precious metals such as platinum, palladium, osmium and iridium, and in recent years, due largely to an increasing market, many secondaries plants have undertaken the commercial production of selenium and tellurium. The complete up-to-date secondaries plant, or silver refinery as it is usually called, is therefore equipped for the production in marketable form of from six to eight metals. The physical plant and operations may be separated into six main divisions: 1. Slime treatment, in which the raw slime is treated by wet methods for the removal of its high copper content and portions of other impurities such as arsenic, selenium and tellurium. 2. Furnace refining, in which the remainder of the base-metal content of the slime is removed by fluxing and fire-refining. 3. Electrolytic parting and refining, in which the silver and gold are parted and obtained in the pure state. 4. Melting of silver and gold into marketable form. 5. Recovery and refining of the more precious metals. 6. Recovery and refining of selenium and tellurium. The Silver Refinery of the Raritan Copper Works at Perth Amboy, N. J., is a complete secondaries plant and the following description of its equipment and processes is, in a general way, typical of other plants of its kind. Slime Treatment The raw slime, pumped with a minimum amount of cell solution from the electrolytic copper refinery, is discharged into the center of circular settling tanks 15 ft. in diameter by 8 ft. deep, where the slime settles out and the solution overflows peripherally to return to the copper refinery by gravity. The slime is then dropped through a bottom outlet to a

Jan 1, 1934

By E. Luttgen

The substance referred to in the title is the artificially prepared basic carbonate of magnesia, a compound of the carbonate with the hydroxide. It is the "block-magnesia " of commerce, the magnesia alba of the pharmacist. Its composition, though somewhat indefinite, may usually be expressed by the formula : 4MgCO3,Mg(OH)2, 5H2O; it is found to vary slightly with the details of the method of preparation. This substance has been employed recently with much reported success, as a non-conductor of heat. It is moulded to form coverings suitable for steam-pipes and their fittings and sectional jackets for boilers and cylinders; it is furnished also in forms suitable for lining refrigerators, walls and roofs of buildings, fire-proof safes, etc. It was with a view of ascertaining the efficiency of this material as a non-conductor, or, rather, its relative efficiency among the various non-conducting materials in use, that the writer made the experiments about to be described. A block of magnesium carbonate or magnesia alba exhibits some interesting physical qualities. It is a smooth, white, close-grained solid, in outward appearance resembling a block of Paris plaster. It possesses the lightness of cork, the porosity of sponge, and withal a degree of firmness and strength that, in view of its levity, is quite remarkable. To examine more closely the properties of this substance, a number of 1-inch cubes were sawed from the commercial block-carbonate, also some bricks, that is, blocks measuring accurately 2 x 4 x 8 inches, the dimensions of an ordinary brick. The cubes weighed from 2.2 to 2.7 grammes, the bricks weighed 140 to 175 grammes (5 to 6 ounces). The bricks were carefully measured and weighed, and placed in vessels containing distilled water, in which they became gradually submerged, owing to the displacement by water of the air inclosed in the structure of the magnesium carbonate. After twenty-four hours the blocks were removed from the water, dried superficially by contact with filter-paper and weighed. From the increase in weight, the volume of the water absorbed, and consequently that of the air displaced by it, were obtained. For example: a block which when dry weighed 155

Jan 1, 1887

By Eric J. Bradshaw

For several hundred years the petroleum industry has flourished in Burma and at the close of the eighteenth century there were over five hundred producing wells in the Yenangyaung field. These were laboriously dug by hand and were exceedingly primitive, yet even today a small part of India's total production is obtained from hand-dug wells. The Indian Empire, the cradle of the oil industry, today produces but an unimpressive fraction of the world's supply of petroleum, not because the size of her contribution has diminished, but because it has remained more or less stationary while other countries have far outstripped her during the prodigious increase in the world's production of petroleum in recent years. Though for the past 10 years the total production in India has been remarkably constant, it has become increasingly difficult to maintain this output and at any rate from the older fields a slow decline may be anticipated unless new productive horizons are discovered. Production figures for the 10 years 192&1929 (the last year for which figures are available) are given by fields in Table 1. Crudes of Burma and Assam The bulk of India's production comes from the Yenangyaung and Singu fields, from which the crudes are very similar, the only important difference being that the oil from the Singu-Yenangyat structure contains a higher percentage of lighter fractions. The Burma crudes resemble that of the Panhandle of Texas and have a high content of solid paraffin, though strictly speaking the oil is of mixed base with a low content of asphaltum. With the exception of the negligible production from Sabe, the Burma crudes do not require dehydration; the sulfur content is very low and is innocuous. A small amount of naphthenic acids occurs in the kerosene and intermediate oil fractions while the lubricating fraction is practically free from acid. The ash content is low and the average A.P.I. gravity of mixtures of Yenangyaung and Singu oil is 36.4. Burma crudes require only light refinery treatment and practically dl the fractions are merchantable. Part of the gasoline supply is stripped

Jan 1, 1931

By C. D. Woodward

PrioR to 1902, the tramming of ore from the stopes to the shafts, in the Butte mines, was done by man or animal power, but the demand for greater tonnage and the need for more improved methods of tramming the ore resulted in the installation of the compressed-air locomotive in a few mines. Some of the objections to animal haulage were thus eliminated, but this locomotive was not generally adopted, because of a number of limiting features. It was superseded by the electric trolley locomotive. The early types of trolley locomotives were not satisfactory from the operators' viewpoint, but they had many economic advantages and after a number of years, in which improvements were constantly made in the structural details, they became dependable, so that the use of animals for main haulage in the mines has now been practically abandoned. There are now operating in the Butte mines of the Anaconda Copper Mining Co., 185 trolley-type locomotives, each of which has replaced five animals. It cost approximately $50 per month to keep an animal, hence the economies that resulted fully justified the expenditure of electrifying the haulage systems. The haulage conditions in this company's mines possess many advantageous features that arc not always found in underground mine workings. The drifts and crosscuts are large, approximately 5 ft. (1.5 m.) wide by 71/2 ft. (2.3 m.) high, and have curves of no less than 18 ft. (5.5 m.) radius; and the roadbeds of the drifts and crosscuts have a uniform grade of 0.5 per cent. toward the shaft, or in favor of the loaded trips. In all of the mines, except two, the track gage is 18 in. (45.7 cm.): and all tracks in the main haulageways are laid with 25-lb. (11.3 kg.) rails. The stations at the shaft are large, well-lighted, clean, and cool. The average temperature of the stations, however, is about 75" F. (24" C.), while the average temperature in some of the drifts and crosscuts is 92" I?. (33.5" C.). As the orebodies lie at varying distances from the hoisting shafts,

Jan 1, 1923

By C. D. Woodward

PrioR to 1902, the tramming of ore from the stopes to the shafts, in the Butte mines, was done by man or animal power, but the demand for greater tonnage and the need for more improved methods of tramming the ore resulted in the installation of the compressed-air locomotive in a few mines. Some of the objections to animal haulage were thus eliminated, but this locomotive was not generally adopted, because of a number of limiting features. It was superseded by the electric trolley locomotive. The early types of trolley locomotives were not satisfactory from the operators' viewpoint, but they had many economic advantages and after a number of years, in which improvements were constantly made in the structural details, they became dependable, so that the use of animals for main haulage in the mines has now been practically abandoned. There are now operating in the Butte mines of the Anaconda Copper Mining Co., 185 trolley-type locomotives, each of which has replaced five animals. It cost approximately $50 per month to keep an animal, hence the economies that resulted fully justified the expenditure of electrifying the haulage systems. The haulage conditions in this company's mines possess many advantageous features that arc not always found in underground mine workings. The drifts and crosscuts are large, approximately 5 ft. (1.5 m.) wide by 71/2 ft. (2.3 m.) high, and have curves of no less than 18 ft. (5.5 m.) radius; and the roadbeds of the drifts and crosscuts have a uniform grade of 0.5 per cent. toward the shaft, or in favor of the loaded trips. In all of the mines, except two, the track gage is 18 in. (45.7 cm.): and all tracks in the main haulageways are laid with 25-lb. (11.3 kg.) rails. The stations at the shaft are large, well-lighted, clean, and cool. The average temperature of the stations, however, is about 75" F. (24" C.), while the average temperature in some of the drifts and crosscuts is 92" I?. (33.5" C.). As the orebodies lie at varying distances from the hoisting shafts,

Jan 1, 1923

By Russell W. Mumford

LITHIA compounds have a place in pharmaceutical and other chemical industries and lithium minerals in glassmaking and ceramics. The metal, although rare, is used to a minor extent in alloys. During the nearly 50 years of production of lithium minerals in the United States, the silicate mineral spodumene has continued as the chief source of raw material for the manufacture of lithium salts. Although twice as much lepidolite, a lithium mica, has been mined, most of it has been used in the making of certain types of glass. Amblygonite has been an additional but minor source of lithium compounds. Triphylite, petalite, and zinnwaldite have also been utilized in the past. All of these commercial lithium minerals contain low percentages of lithium (Table 1). In 1938, a new raw material for manufacture of lithium compounds made its appearance. This product was crude dilithium sodium phosphate (Li2NaPO4), obtained as a by-product of manufacture of potash and soda chemicals from the brine of Searles Lake, California. Searles Lake, which is now dry, lies in the extreme northwest corner of San Bernardino County, California, and consists of a large mass of salts. It was estimated by the United States Geological Survey that the crystal body contained about 25 pct voids, which are filled with a saturated brine. The brine consists mainly of the sulphates, chlorides, carbonates, and borates of sodium and potassium. Several other acid radicals, including phosphates, are present. Lithium is present in the brine in an amount corresponding to 0.01 15 pct Li2O. In the course of evaporation of water from the brine, during the process of manufacture of sodium and potassium chemicals, dilithium sodium phosphate crystallizes out and is recovered by a flotation operation. The lithium concentrate is filtered and dried and is then ready for shipment. It analyzes from 19 to 21 pct Li2O and now constitutes the highest known grade of crude lithium material. It is and will continue to be a major source of lithium for manufacture of lithium products. The variation in lithia content of the commercial minerals as mined is due to replacement of the lithia by soda and potash, to partial alter-

Jan 1, 1949

By M. H. Merriss

Some years ago, at the plant of the Baltimore Copper Smelting & Rolling Co., the receipt of large quantities of copper blister running high in lead, nickel, and arsenic resulted in the formation of a great amount of very foul slag, in the anode furnaces. A typical analysis of this slag was: Gold, oz. per ton......... 0.09 Arsenic, per cent.......... 0.60 Silver, oz. per ton......'.. 13.20 Antimony, per cent........ 0.50 Copper, per cent......... 19.50 Silica, per cent............ 28.30 Lead, per cent........... 11.90 FeO, per cent............. 19.20 Nickel, per cent.......... 4.60 CaO, per cent............. 1.60 The problem was to get out the copper in marketable form, to save the gold, silver, and particularly the nickel, and to get rid of as much as possible of the lead, arsenic, and other elements that were valueless to the Baltimore plant. In a copper refinery that does not take custom material for matte smelting, the usual method is to smelt the anode slag with coke in a reducing furnace, the black copper thus formed being sent back to the anode furnaces; this was the custom at Baltimore. An average anode slag will contain, perhaps, 40 per cent. copper and such small quantities of lead, nickel, etc., that smelting will get rid of most of these impurities in the black-copper furnace slag. To treat such an impure slag in this way, however, would result in a large nickel loss, and would send back to the anode furnaces all the lead and nickel not so lost, where it would be slagged off again and returned to the black-copper furnace as a slag still more concentrated in impurities. The result would probably be a constantly increasing amount of anode slag containing a likewise constantly increasing percentage of impurities. To avoid such a disastrous closed circuit some other process had to be devised. A small multiple-tank room, built for impure copper as an adjunct to the main series electrolytic refinery, was available, so the following standard process was suggested:

Jan 1, 1924

By B. E. Parsons

Curtailment of production of crude oil, to the extent of effecting an approximate balance in supply and demand, was a problem confronting the oil industry in California throughout the year 1930. At the beginning of the year, with drilling operations only slightly checked, the California industry faced a steadily increasing potential production, an actual production in excess of market requirements and stocks of crude oil and refined products which had reached staggering proportions. During the year, the intensive development of the Playa Del Rey field and extensions to several oil fields, together with flush production from numerous large wells from both new and old fields, caused a steady increase in the state's potential production to a record peak in November of 1,186,000 bbl. daily. Despite the burden of this steady stream of flush production and the handicap of incomplete cooperation in several fields, curtailment successfully lowered the trend of crude oil production in California, except for the period of an open-flow test to determine actual potential production in several important fields in February. Under the curtailment programs in effect, the state's production of crude oil for the year was reduced 22 per cent. under the production of 1929 and even slightly under the production for the years 1927 and 1928. The total stocks of crude oil and refined products were reduced 2.7 per cent. during 1930, as compared to an increase of 30 per cent. in total stocks of all products during 1929. Drilling operations were reduced 28 per cent. as compared to drilling activities during 1929. Voluntary curtailment of drilling programs by many operators, particularly the major companies, accounts for the greatest portion of the reduction in drilling activity. The decline in drilling activity at Santa Fe Springs and in the east-side fields of the San Joaquin Valley was more than offset by development in new fields and extensions to deeper zones of old fields. There were 755 new wells completed during 1930, as compared to 910 completions in 1929. At the close of the year, 220 wells were drilling in the oil fields of California, 9 of which were being drilled in search of deeper producing horizons.

Jan 1, 1931

By Raymond Mancha

THE number of installations of propeller mine fans completed during the years of 1936 and 1937 is evidence of the increasing popularity of the propeller fan with the American mining industry. During the period from 1931 to 1936, there were several different low-pressure, low-efficiency propeller fans available, which filled a definite need in replacing inefficient centrifugal fans operated at comparatively low pressure by means of purchased power. Since 1936, however, the trend toward the propeller fan has greatly increased, as propeller fans are now available practically without pressure limitations and capable of efficiencies high enough to warrant replacement of efficient centrifugal fans in many instances. Few manufacturers of propeller mine fans base their fan-operating characteristics upon similar test methods, primarily because of inadequate facilities for testing in the factory and the need of a test code incorporating a calibrated duct or nozzle that makes possible the testing of large propeller fans quickly, accurately and without prohibitive expense and space requirements. As a result, fan manufacturers have resorted to various methods for testing large propeller fans in the factory, and different yardsticks have produced uncomparable and often inaccurate performance data. It is the purpose of this paper to describe and discuss in detail the test procedure of the Jeffrey Manufacturing Co., which has been proved both accurate and practical. Fig. 1 shows a plan, a side elevation and two end elevations of the test duct with a propeller fan of the exhaust type in place. Testing propeller fans exhausting permits greater accuracy than testing these fans blowing, because in the former uniform flow conditions are more easily established at Pitot tube stations where fan pressure and air-volume measurements are desired. Any residual rotation remaining in the air discharged from a propeller fan blowing into a test duct must be removed before an attempt is made to obtain accurate pressure and volume readings. Although various devices for straightening the air may be placed between the blowing fan and the volume-measuring station without resulting complications, uniform flow so obtained at the pressure-measuring station necessitates corrective calculations to compensate for duct resistance

Jan 1, 1939

By W. A. Scheuch, J. Walter

Ordinarily secondary copper, unless electrolytically refined, is reclaimed directly as foundry ingots used in the manufacture of copper-rich alloy castings. This use does not require the elimination of the impurities to the degree required if the recovered'metal is to be used for electrical purposes where a high electrical conductivity is of prime importance. However, as a part of the general policy of reusing its own scrap and by-products wherever possible, the Western Electric Co. at its Hawthorne Works is recovering its secondary copper as wire bars which are delivered to its own rod and wire mill and there processed into wire of high electrical conductivity. This departure from the usual recovery scheme has been accomplished through the careful classification and sorting of the material entering the furnace charges and the careful control of the subsequent melting and refining in a reverberatory furnace. Tests conducted over a period of approximately four years have shown that the quality of wire bars produced from selected secondary copper is equal to that of wire bars produced by the electrolytic refineries. The interest which has been exhibited in the process by those who have seen it has prompted the following general description. It is the authors' opinion that the recovery of secondary copper will become more and more an important factor in the copper production industry. The description is largely of the refining furnace and its operation, but it must be remembered that careful classification and sorting of the scrap materials to eliminate impurities are just as important as the furnace operation toward obtaining a satisfactory final product. Classification and sorting do not lend themselves easily to description; they must, just be done. It should also be recognized at the outset that constant intelligent supervision is requisite to the success of the process because there are so many ways in which impurities can find their way into the final product. Secondary Copper Used for Wire Bars Only clean secondary copper of the grades known to the trade as Numbers 1 and 2 are melted for wire-bar manufacture. This material, supplemented by that obtained from various manufacturing processes

Jan 1, 1930

By Robley D. Evans, Gerald L. Schroeder

Advanced techniques for control of radon (Rn) daughter product concenrrations (working levels, WL) in the uranium mines are discussed. Understanding the physical laws which govern the flux of radon into a mine, the growth and decay of the radon daughters, and the particulate nature of the daughters when suspended in air allows ventilation personnel to improve the quality of mine air with no increase in ventilation rate. The task of controlling, in a mine atmosphere, the short-lived nuclides produced in the decay chain of radon is a unique problem and as such should be approached with ventilation techniques specific to the problem. For most mines this has not been the case. Rather, procedures for removing these airborne radioactive nuclides have been borrowed directly from ventilation experience in mines where dilution ventilation was the traditionally accepted approach for air purification. With radon daughter products, this has often led to frustrating difficulties and expense. Primary origin of the airborne radioactivity is the a-ray-emitting noble gas, radon (222Rn, Rn), a nuclide formed by the decay of radium (226Ra, Ra). Radon, being a gas, may escape from its parent crystal and diffuse through the parent mineral into the interstices of the rock body. In a sandstone structure, about 20% of all the radon formed may find its way into the interstices of the rock. If a cavity such as a mine is nearby, the radon may diffuse through the rock interstices into the mine. While radium is usually highly concentrated in uranium ores, it is also found in varying concentrations in all minerals. Radon is therefore present in all minerals. In normal glacial till, the equilibrium interstitial radon concentration often equals 5000 pCi (picocurie, also uuCi) Rn per liter of pore volume.' In normal granitic rocks, the interstitial radon concentration often approaches 30,000 pCi per 1. Considering these typical, high-radon concentrations, radioactivity from airborne of daughter products is a potential problem unique not only to the uranium mining industry and should be considered as a potential hazard in all underground environments.

Jan 1, 1970

By T. Sterry Hunt

I HAVE in a previous communication called the attention of the Institute to the geognostical relations of the crystalline iron ores belonging to the Eozoic rocks of North America, at which time I noticed (1) those associated with the gneisses of the Laurentian series, (2) those of the crystalline schists of the Huronian, as seen in Northern Michigan and in many localities along the Appalachians ; (3) those of Southeastern Missouri associated with petrosilex porphyries and schistose rocks, and presumed to be nearly of the same age with those of the Huronian schists; and (4) the highly titaniferous ores of the Norian or Labradorian series from Essex County, N. Y., and from various parts of Canada. It may here be remarked that, although the presence of titanium is most marked in the Norian ores, this objectionable element is sometimes found in the schistose ores of the Huronian, and to a lesser extent in certain Laurentian magnetites. The ores of each of these geological divisions have their individual peculiarities, which serve to distinguish them to such a degree that the magnetites and specular ores of the Laurentian are as dissimilar to those of the Huronian as are the crystalline silicated rocks of the two series. As it happens that these mineralogical dissimilarities correspond to differences in composition and in adaptability to different processes of manufacture, which, in the present condition of the iron industry, are objects of special consideration to metallurgists, it will be seen that these geognostical distinctions become of great practical importance. During the past year I was desired by the Geological Commissioners of Pennsylvania to devote a few weeks to certain geological studies in the eastern part of the State, in the course of which I was enabled to make, with regard to its crystalline iron ores, some observations to which I desire to call the attention of the Institute. I may mention, in passing, that the great South Mountain belt, from the Schuylkill to the Delaware, is composed of Laurentian rocks, in which are found the characteristic ores of the series like those of the Highlands of New Jersey and New York, and of the Adiron-

Jan 1, 1876

By C. D. Woodward

PRIOR to 1902, the tramming of ore from the stopes to the shafts, in the Butte mines, was done by man or animal power, but the demand for greater tonnage and the need for more improved methods of tramming the ore resulted in the installation of the compressed-air locomotive in a few mines. Some of the objections to animal haulage were thus eliminated, but this locomotive was not generally adopted, because of a number of limiting features. It was superseded by the electric trolley locomotive. The early types of trolley locomotives were not satisfactory from the operators' viewpoint, but. they had many economic advantages and after a number of years, in which improvements were constantly made in the structural details, they became dependable, so that the use of animals for main haulage in the mines has now been practically abandoned. There are now operating in the Butte mines of the Anaconda Copper Mining Co., 185 trolley-type locomotives, each of which has replaced five animals. It cost approximately $50 per month to keep an animal, hence the economies that resulted fully justified the expenditure of electrifying the haulage systems. The haulage conditions in this company's mines possess many advantageous features that are not always found in underground mine workings. The drifts and crosscuts are large, approximately 5 ft. (1.5 m.) wide by 7 ½ ft. (2.3 m.) high, and have curves of no less than 18 ft. (5.5 m.) radius; and the roadbeds of the drifts and crosscuts have a uniform grade of 0.5 per cent. toward the shaft, or in favor of the loaded trips. In all of the mines, except two, the track gage is 18 in. (45.7 cm.), and all tracks in the main haulageways are laid with 25-lb. (11.3 kg.) rails. The stations at the shaft are large, well-lighted, clean, and cool. The average temperature of ,the stations, however, is about 75° F. (24° C.), while the average temperature in some of the drifts and crosscuts is 92° F. (33.5° C.).

Jan 2, 1922

By Will L. Clark

He who enters a mining claim within an Indian reservation of the United States of America acquires no rights thereby, because of the fact that the lands within such Indian reservation are not a part of the public domain, and cannot be located or acquired as mineral land. However, where such an entry is authorized as to a particular reservation by an Act of Congress, such claims as may be ontered under such authorization are thereby segregated from the reservation, and the Indian title is oxtinguished. Under the Choctaw Constitution, any citizen of that nation, in other words any Choctaw Indian, who discovered a coal mine, acquired an exclusive right to all coal within a radius of 1 mile. The laws of the Chickasaw nation provided for the formation of corporations to develop coal and other mines, with authority to contract with others to develop and work the mines. Under these laws, leases were made; but Congress subsequently abrogated all existing leases, prohibited all persons from receiving royaltics from such mines, and provided that all coal within the nation should remain the common property of the tribes. , Such leases are now expressly prohibited by an Act of Congress (32 United States Statutes at Large, 655). All leases of mineral lands upon Indian reservations must now be made under regulations promulgated by the Secretary of the Interior, and the royalties must' be paid into the United States Treasury for the benefit of the tribes. In Canada the Indians have no rights to the royal mines and minerals, and the government can make no stipulation with the Indians which would affect the rights of the Province in which the lands are situated. Therefore, while it is true that under our present law no rights can be acquired to a mining claim within an Indian reservation, it seems to be fully within the authority of Congress to make laws, giving such rights to mineral locators as it may deem necessary or expedient. There is a demand for a general law that will permit mining upon Indian reservations, and I am informed that most of the members of both houses of Congress from the Western States are in favor of Congress pass-

Jan 1, 1915