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The Jeffrey Company Opens Branch in Seattle The Jeffrey Manufacturing Co. of Columbus, Ohio, announces the re-opening of its Northwestern Branch Office at Seattle, Wash., and the appointment of Mr. Percy E. Wright, Consulting Mechanical Engineer, as District Manager for Oregon, Washington, Alaska, British Columbia and Alberta. Mr. Wright, who has been in the Northwest since 1910, and whose connection with the Jeffrey company dates back to 1902, has' had a wide and varied experience and training in the handling of the Jeffrey line which will enable him to be of great assistance to customers in solving their elevating, conveying and transmission problems. Trade Catalogs To a majority of the public, the name 'DuPont suggests military powder-munitions of war. The DuPont Products Book A-430 (April, 1916) lists 251 distinct commodities made. and sold by this company, many of which are far removed from destructive work. Mining men are fully cognizant of the need for explosives in constructive work, but they may be surprised to know that side by side with the powder and dynamite this company manufactures such peaceful articles as substitute leather, combs and collar buttons. The substitute for leather is Fabrikoid, varying in weight from a quality light enough for bookbinding to one heavy enough for trunks and automobiles, and the combs and collar buttons (with scores of other articles) are made from Pyralin. The book also contains a long list of chemicals, and a shorter list of special products and miscellaneous materials such as charcoal, wood flour and saltpeter. The Jeffrey Manufacturing Co. of Columbus, Ohio, making elevating, conveying, crushing, screening and power transmission machinery, has just issued its. latest Bulletin, No. 177, :featuring self-propelling wagon and truck loaders for handling crushed stone, sand, gravel, clinker, coke, etc. These machines are described as having a capacity of 1 to 1 ½ cu. yd. of material per minute, with power to load crushed stone maximum size pieces through 3 ½ -in. ring and to load trucks or wagons in 3 or 4 min. The self-propelling device is designed to enable one man to operate the loader as it is fed into the pile, and to move the machine about under its own power.

Jan 7, 1916

By E. Gybbon Spilsbury

THE introduction of underground machinery in mines, and especially the invention of the rock drill, called attention to the necessity for some motive power to drive them. The use of steam generators underground is as a general thing inadmissible, owing to the, difficulties of ventilation and the transportation of fuel, and the great loss of power by condensation in the pipes, when surface generators are used, added to the inconvenience of getting rid of the exhaust steam, has precluded the direct use of steam for this class of machinery. Water as a power has with very few exceptions proved a failure, owing to its weight and incompressibility, and there-fore the attention of mining engineers has very naturally turned to the use of compressed air. This agent not only answers all the requirements for power, but has the double advantage of greatly assisting in thoroughly ventilating remote workings, and in cooling the underground atmosphere. It is therefore clear that the successful introduction of underground machinery is dependent on the economical production of good and efficient air-compressing machinery. Although many improvements have of late years been introduced in this class of machines, the most of them are open to serious objections, the chief of which are the very small duty they perform for the power expended, and their great expense, due to the complexity of their construction. This latter fault is the chief reason why the introduction of rock drills and other underground engines is so limited, as comparatively few mines can afford to expend the required capital for the installation of a complete compressing plant. But with the introduction of a cheap and effective compressor, there is no doubt that power drills will become as generally used in mines as the hand drills are now. The great excess of power required in most machines to compress air over that given out again by the use of the air thus compressed (amounting as it does in most cases to sixty per cent.) is well known to all mining engineers. Of course a portion of this loss is due to the friction of the air through the pipes, and will always occur however effective the machine used maybe, but the chief cause -of the

Jan 1, 1880

THE Institute assembled on Tuesday evening, October 24th, in the hall of the Franklin Institute, Mr. Frank Firmstone, VicePresident, in the chair. Mr. J. Price Wetherill, of Tremont, Pa., read a paper on An Outline of Anthracite Coal Mining in Schuylkill County, Pa. The paper was discussed by Messrs. Coxe, Rothwell, Heinrich, Harden, and Symons. The second session was held on Thursday evening. Mr. A. L. Holley, Chairman of the International Committee, appointed by the Institute to consider the nomenclature of iron and steel, offered the following report of the committee, signed by all the members: WHEREAS, The recent production of soft, cast, malleable compounds of iron by the Bessemer, the Siemens-Martin, and the crucible steel processes appears to demand a new nomenclature of iron compounds, for the following reasons: 1st. The term "steel," by which these soft products are commercially and professionally designated in England and in the United States, does not completely distinguish them from previously existing "steel which would harden and temper. 2d. A nomenclature recognized in all languages seems desirable, as well for commercial as for scientific purposes, especially as lawsuits, already commenced, depend on the meaning of the term " steel." 3d. Although homogeneity, due to fusion, is usually recognized, and is by this committee recognized as the most definite characteristic of both hard and soft steel, this quality may be equally well expressed in other terms, thus leaving the old term, " steel," to define the malleable compounds of iron, which will harden and temper. Therefore, resolved, That this committee recommends the following nomenclature : 1. That all malleable compounds of iron with its ordinary ingredients, which are aggregated from pasty masses, or from piles, or from any forms of iron not in a fluid state, and which will not sensibly harden and temper, and which generally resemble what is called " wrought iron," shall be called Weld Iron (German, Schweisseisen; French, fer soudé). 2. That such compounds, when they will from any cause harden and temper, and which resemble what is now called puddled steel," shall be called Weld Steel (German, Schweiss stahl; French, acier soudé).

By E. Gybbon Spilsbury

The introduction of underground machinery in mines, and especially the invention of the rock drill, called attention to the necessity for some motive power to drive them. The use of steam generators underground is as a general thing inadmissible, owing to the difficulties of ventilation and the transportation of fuel, and the great loss of power by condensation in the pipes, when surface generators are used, added to the inconvenience of getting rid of the exhaust steam, has precluded the direct use of steam for this class of machinery. Water as a power has with very few exceptions proved a failure, owing to its weight and incompressibility, and therefore the attention of mining engineers has very naturally turned to the use of compressed air. This agent not only answers all the requirements for power, but has the double advantage of greatly assisting in thoroughly ventilating remote workings, and in cooling the underground atmosphere. It is therefore clear that the successful introduction of underground machinery is dependent on the economical production of good and efficient air-compressing machinery. Although many improvements have of late years been introduced in this class of machines, the most of them are open to serious objections, the chief of which are the very small duty they perform for the power expended, and their great expense, due to the complexity of their construction. This latter fault is the chief reason why the introduction of rock drills and other underground engines is so limited, as comparatively few mines can afford to expend the required capital for the installation of a complete compressing plant. But with the introduction of a cheap and effective compressor, there is no doubt that power drills will become as generally used in mines as the hand drills are now. The great excess of power required in most machines to compress air over that given out again by the use of the air thus compressed (amounting as it does in most cases to sixty per cent.) is well known to all mining engineers. Of course a portion of this loss is due to the friction of the air through the pipes, and will always occur however effective the machine used may be, but the chief cause of the

Jan 1, 1880

THE Institute assembled on Tuesday evening, October 24th, in the hall of the Franklin Institute, Mr. Frank Firmstone, Vice-President, in the chair. Mr.. J. Price Wetherill, of Tremont, Pa., read a paper on An Outline of Anthracite Coal Mining in Schuylkill County, Pa. The paper was discussed by Messrs. Coxe, Rothwell, Heinrich, Harden, and Symons. The second session was held on Thursday evening. Mr. A. L. Holley, Chairman of the International Committee, appointed by the Institute to consider the nomenclature of iron and steel, offered the following report of the committee, signed by all the members: WHEREAS, The recent production of soft, cast, malleable compounds of iron by the Bessemer, the Siemens-Martin, and the crucible steel processes appears to demand a new nomenclature of iron compounds, for the following reasons : 1st. The term "steel," by which these soft products are commercially and professionally designated in England and in the United States, does not completely distinguish them from previously existing "steel" which would harden and temper. 2d. A nomenclature recognized in all languages seems desirable, as well for commercial as for scientific purposes, especially as lawsuits, already commenced, depend on the meaning of the term "steel." 3d. Although homogeneity, due to fusion, is usually recognized, and is by this committee recognized as the most definite characteristic of both bard and soft steel, this quality may be equally well expressed in other terms, thus leaving the old term, "steel," to define the malleable compounds of iron, which will harden and temper. Therefore, resolved, That this committee recommends the following nomenclature : 1. That all malleable compounds of iron with its ordinary ingredients, which are aggregated from pasty masses, or from piles, or from any forms of iron not in a fluid state, and which will not sensibly harden and temper, and which generally resemble what is called " wrought iron," shall be called WELD IRON (German, Sehweisseisen; French, fer soudé) 2. That such compounds, when they will from any cause harden and temper, and which resemble what is now called "puddled steel," shall be called WELD STEEL (German, Schweiss stahl; French, acier soudé).

Jan 1, 1877

By John Freeman

THE die pressing of brass may be described as a method of producing irregularly shaped parts of brass and other copper alloys by hot deformation in a die under pressure. Die pressing of brass was first developed as an improvement on sand castings in order to obtain irregularly shaped articles of brass with superior surfaces, a closer tolerance in dimensions, a denser structure, freedom from porosity and elimination of the relatively large amount of scrap invariably attached to sand castings. The freedom from sandy surfaces with consequent greater tool life in machining operations was also recognized as well as elimination of losses due to the uncovering of blowholes in machining operations. Die pressing also gave alloys of superior strength. Die pressings today are made from extruded rod or shapes, according to design of the part to be made. The greater number of pressings are made from round rod, because of its relatively lower cost and ease of handling. The rod is first sheared or sawed into desired lengths, the diameter of rod used and length of "slug" or "rivet" depending upon ultimate weight and shape of the die-pressed part to be made and design of die. The dimensions of the slug are figured so as to give the, minimum amount of scrap to be sheared from the pressing as it comes from the-die. Extruded shapes having I, T or X sections are often used when the finished part is to have a similar shape or heavy sections are joined by relatively light sections of considerable length. A rod bent in the shape of a U is also used on occasion, for similar reasons. Proper shearing of the slugs is of considerable importance. The sheared ends of the slugs should be as flat and straight as possible. Improperly sheared ends having an angle to the axis of the bar or a rough, uneven surface are liable to give folds or laps in the finished pressing and proportionately high rejections. The property of shearing varies considerably with different alloys and should be considered in the selection of a material for a given part. Where satisfactory shearing is not possible, the slugs may be cut from the bar by power saws. Extruded

Jan 1, 1931

By Henry B. Smith, S. Paul Lindau

ThREe years ago it was decided by the management to granulate the matte that is produced in the smelter of the St. Joseph Lead Co. at Hereulaneum, Mo., thereby doing away with a large amount of labor in handling the matte and in subsequent crushing. On Mar. 1, 1915, the granulator was put in operation and up to Jan. 1, 1916, 18,735 tons had been granulated. The four blast furnaces have a daily output of about 280 tons of pig lead and 100 tons of matte assaying about 11.0 per cent. Pb. It is expected that projected improvements in roasting methods will eliminate more sulphur from the charge, and cut down the matte-fall to about one-half of the present figure. The blast furnaces are tapped into movable forehearths or settlers, 6 ft. by 4 ft. by 22 in., the slag overflowing into 27-cu. ft. slag cars which are hauled to the dump by electric locomotives. Previous to the adoption of granulation, the matte was tapped from the forehearths into small slag pots which were dumped after cooling. The matte cakes were broken with sledges, and transported to the crushing plant for fine crushing and screening. Here the matte was reduced to 1/4-in. size before being fed to the roaster bins. A Wedge and a Holthoff mechanical furnace are used for preroasting before sintering on the Dwight and Lloyd machines. The matte is returned to the furnaces as an iron flux until the gradually accumulating copper content reaches about 7 per cent., after which it is put aside to be concentrated in a small copper blast furnace, the resultant high-grade matte being sold. When the matte does not settle readily from the slag, two settling devices are often used, the second one being a large catch-pot, which gathers any matte that may overflow from the forehearth, the slag then overflowing from the catch-pot into the slag cars. When full of matte, the catch-pot is removed, allowed to cool, and the contents broken and crushed. a With the present plan of granulating, the matte is tapped into 6-cu. ft. iron ladles. These are transported to the granulating plant by a 5-ton

Jan 1, 1917

TO THE, BOARD OF DIRECTORS OF THE AMERICAN INSTITUTE OF MINING AND METALLURGICAL ENGINEERS Gentlemen -The following report covers briefly some of the more important activities of the Institute during the year 1923. In my report for the year 1922, I drew attention to the falling off in membership of the Institute due to the depressed condition of the mining industry in several lines and the inability of many of our members to find profitable employment in mining or its associated branches. A number who were unemployed during 1922 established connections during 1923, but a still greater number have been forced to resign or drop their membership during 1923 Fortunately, the number dropped is not so great as in the previous year. The Employment Service conducted by, the four Founder Societies bears witness to the trend in business For the young men just out of college, there are plenty of opportunities at small salaries, there are plenty of opportunities for them as laborers; but for the mature members, those of experience, there are few calls During the last eighteen months, our Employment Service has been able to place only six of our members out of every hundred engineers for whom it has found work. Another loss which this Society has suffered, but which is not felt so keenly by our sister societies, is in its foreign members. The A. I M. E. has always had a large foreign membership, but of recent years exchange has been so heavily against many European and South American coun¬tries that a large number of members residing abroad have been compelled to relinquish their membership Almost invariably these members express keen regret because of the necessity that confronts them, and almost invariably the writers express hope that present conditions will not last long and that they will soon be able to ask for reinstatement. Having stated the darkest side of the picture first, it may now be drawn to your attention that in spite of these losses the number of persons applying for membership was decidedly encouraging. From the quality point of view, the membership has not gone back¬ward The Membership Committee has declined to recommend many

Jan 1, 1923

By Edwin A. Sperry

The use of steam-stamps in the crushing of ore for the purpose of amalgamation has been very limited, and little has been written on the subject. As the writer has been operating a mill of this kind during the past year, it is possible that he may be able to present a few points in regard to mill-practice in this line which will be of interest. The mill herein referred to contains two Tremain steamstamps, a more detailed description of which will be given below. A bond and lease had been taken on a property on Cross mountain, Gunnison county, Colo., and the parties operating wished to prospect it thoroughly and did not wish to ship out the ore, owing to high freight-rates. They looked around to find some mill that would answer the purpose and not be too expensive. The steam-stamp in question was finally decided on, and the writer was employed to erect and operate it. The economy of construction was demonstrated at the outset. The stamps were dropping within ten days from the time that the machinery was unloaded on the ground. A large portion of this period was consumed in waiting for supplies and fittings which should have been on the ground at the Hame time with the machinery. Ore.—The ore to be treated was a mixture of white, porous quartz, with the decomposed and undecomposed oxides of iron and manganese in varying proportions, from the pure white quartz to solid pieces of the oxides. It appeared to be the product of replacement in a soft dolomite at or near the line of contact with a dike of porphyry. On careful examination with the aid of a microscope it was found that the gold was in the form of an extremely thin film over the surfaces of the quartz, making only a bronzy-yellow coating, quite readily distinguished from the film of iron oxide, which was also present. Mill.—The mill was constructed on the usual plan, with the ore-bin above and against the hill, which was cut into for the

Jan 1, 1897

TO THE BOARD OF DIRECTORS OF THE AMERICAN INSTITUTE OF MINING AND METALLURGICAL ENGINEERS Gentlemen -The following report covers briefly some of the more important activities of the Institute during the year 1923 In my report for the year 1922, I drew attention to the falling off in membership of the Institute due to the depressed condition of the mining industry in several lines and the inability of many of our members to find profitable employment in mining or its associated branches. A number who were unemployed during 1922 established connections during 1923, but a still greater number have been forced to resign or drop their membership during 1923. Fortunately, the number dropped is not so great as in the previous year. The Employment Service conducted by the four Founder Societies bears witness to the trend in business For the young men just out of college, there are plenty of opportunities at small salaries, there are plenty of opportunities for them as laborers, but for the mature members, those of experience, there are few calls. During the last eighteen months, our Employment Service has been able to place only six of our members out of every hundred engineers for whom it has found work. Another loss which this Society has suffered, but which is not felt so keenly by our sister societies, is in its foreign members The A. I M E has always had a large foreign membership, but of recent years exchange has been so heavily against many European and South American coun¬tries that a large number of members residing abroad have been compelled to relinquish their membership. Almost invariably these members express keen regret because of the necessity that confronts them, and almost invariably the writers express hope that present conditions will not last long and that they will soon be able to ask for reinstatement. Having stated the darkest side of the picture first, it may now be drawn to your attention that in spite of these losses the number of persons applying for membership was decidedly encouraging. From the quality point of view, the membership has not gone back¬ward. The Membership Committee has declined to recommend many

Jan 1, 1923

By John Lovejoy

As the Seminole area, Seminole and Pottawatomie Counties, Okla., appears to be the chief danger zone of overproduction in the United States, it may be of interest to review the production records of the various pools which make up this area; also to dis-cuss the future prospects of these pools, together with the structurally "high" points which may develop into new pools. It is also of interest to appraise the effect of the curtailment program in this general area, which was agreed to in principle by the various Seminole op-erators at a meeting held on May 23 at the offices of W. C. Teagle in New York. There are four large pools in the greater Seminole area. They are, in the order of their importance Seminole City, Bowlegs, Earlsboro, and Searight pools. A glance at the accompanying general map of the area will show their relative situation. The detail maps show the extent and area of these prolific spots. Seminole production comes from the Wilcox sand of Ordovician age, found at a depth of 3900 to 4300 feet. Semninole City Pool:-This pool was discovered in Wilcox sand in July, 1926. By Jan., 1927, there were 123 wells completed, making 146,000 bbl. per day. The field reached its peak of 253,000 bbl. per day the last week of Feb., 1927, with 211 completions and a per well average of 1200 bbl. On July 4 there were 304 wells completed, producing 102,000 bbl., with a per well aver-age of 336 bbl. per day. This pool will cover an area of approximately 3500 acres. It has produced approxi-mately 38,000,000 bbl. to. July 1. Estimates of total ultimate production are around 55,000,000 bbl. or somewhat better than 15,000 bbl. per acre. Some of the individual leases have already yielded 30,000 and 40,000 bbl. to the acre. Bowlegs Pool:-This pool shows 175 drilling wells and 131 completions making 180,000 bbl. per day, with an average per well production of 1380 bbl. It appears that this pool will develop into nearly as large an area as Seminole City. The wells, however, do not give up

Jan 8, 1927

By Northcutt Ely

The subject of this paper implies three questions: whether regulation is necessary; if so, what sort of regulation is wise; and, finally, by what government the power to regulate is to be exercised. In the year 1937 emphasis falls on the third of those questions. This contrasts with the situation prevailing a dozen years ago, when the question was whether regulation was necessary at all; and with the situation a few months ago, when the third question seemed answered by the Supreme Court decisions on the National Recovery Act, Agricultural Adjustment Act and Guffey Coal Control Act, and by the ratification of the Interstate Oil Compact. It then appeared settled that the State and not the Federal Government possessed the regulatory powers and, granting that conservation measures are a recognized necessity, the problem seemed to be to develop the wisest kind of regulation that the Constitution would permit. Today, by virtue of developments during the first months of 1937, the oil industry is faced again by the question of whether the Federal Government is to have power to control its operations, along with those of the other basic industries. Developments in Governmental Control There have been three recent developments. The dominating one is the President's proposal that he be authorized to increase the size of the Supreme Court to 15 members. The implications of that plan ought to be perfectly plain to the oil industry. This suggestion is made in lieu of offering an amendment to the Constitution, to reverse the Supreme Court decisions mentioned. In those decisions the Court held that production does not constitute commerce, and hence that the Federal power to regulate interstate commerce does not extend to the regulation of production. These holdings were contrary to the Government's contention that the stream of commerce begins in the factory and ends with the consumer and may be regulated at any point from beginning to end. That position was urged in the Government briefs in Amazon Petroleum Co. v. Ryan, defending the petroleum code, and repeated as late as Feb. 10, 1937, in the case of National Labor Relations

Jan 1, 1937

By Edwin Chance

DURING the past 10 years, the safe and efficient lighting of the coal mines of this country has received an ever-increasing amount of attention. Several States have passed laws attempting to regulate the type of lamp to be used and the nature of the fuel to be burned, and the mining departments of coal-mining States have generally shown a keen and intelligent interest in this subject. The passage of the recent Employers' Liability Act in Pennsylvania has made it necessary for many coal-mining companies to take out liability insurance, and the companies underwriting such insurance have made it desirable for the insured to permit the use of, none but illuminants of established worth. While these conditions have not obtained for a sufficient length of time to permit the statement that the illumination of coal mines by portable lamps has been standardized, still, considerable progress has been made and the direction of future practice in this branch of coal-mining technology is very evident. Under these conditions it seemed that a review of the methods now used in coal-mine illumination, together, with a brief consideration of the principles underlying these methods, might be of some interest. Miners' lamps may be divided into three classes: The open light, the electric cap lamp and the flame safety lamp. It will be desirable to consider each of these classes separately, as each has properties peculiar to itself and one class is hardly comparable with another. In this country, without question, the open light is the most generally used of all miners' lamps. This fact is explained by the relative freedom of a large proportion of our mines from gaseous conditions, and by the admirable systems of ventilation installed in those that show a tendency toward such conditions. In the metal relines, the miner's candle has had and still has considerable vogue. Because of the small amount of ventilation usually supplied in metal mines, the freedom of the candle from any tendency to produce noxious gases or offensive odors, and the small amount of air it consumes, are. valuable assets, while, because

Jan 2, 1917

By Arthur H. Redfield

In estimating the unmined petroleum reserves of Central America, it is not feasible to employ the methods that have been worked out in thc oil fields of the United States. No producing wells have been brought in and no drilling sections have been made public. It is accordingly necessary to fall back on a crude "barrels per square mile" estimate. The method chosen is a comparison of the structure of the foreign field of unknown reserves with that of some supposedly analogous North American field of which the reserves have been estimated. This method makes no pretense at scientific accuracy, but furnishes a working basis for an estimate. The areal geology of Central America is illustrated in the inap prepared by Sapper and more recently in the geologic map of North America accompanying U. S. Geological Survey Professional Paper No. 71, "Index to the stratigraphy of North America." Disregarding for the present the narrow Quaternary coastal plains and alluvial deposits of the river valleys, three chief zones may be distinguished. These arc: A zone of late eruptive and effusive rocks; a zone of highly folded prr-Cambrian(?) or early Paleozoic crystalline schists and slates, considerably intruded by pre-Tertiary plutonic rocks; and a zone of more or less folded sediments, chiefly of Cretaceous or Tertiary age. The zone of late eruptive and effusive rocks of Central America begins in southeastern Chiapas, Mexico, and extends, with increasing breadth, across southern Guatemala, across practically the whole of El Salvador, and across southern Honduras to the valley of Rio Goascorhn, where the igneous zone attains a width of about 100 mi. (160 km.) East of the Goascordn Valley late eruptives and effusives play a subordinate part, being confined largely to thc Departments of Valle and Choluteca. Dikes and sills of igneous rocks intrude the sedimentary formations of central and northern Honduras. Late igneous rocks cover about four-fifths of the area of Nicaragua. In Costa Rica, late igneous rocks form the diagonal ranges of the Sierra de Guanacaste and the Cordillma Central, and play a part in the upbnild-

Jan 1, 1923

By Edward Pesout

The McGill smelter started operations in the year 1907. The smelter furnaces were fired with run-of-mine coal on grates until April 1911, when oil firing was introduced. Oil firing continued until April 1918, when the initial coal-pulverizing plant was started.' Early Pulverizing Plant Various alterations were made to that plant during its operation, one of the more important being in connection with the system for delivering pulverized coal. In order to minimize coal-dust explosions and fires, the return portion of the main delivery line was eliminated in the year 1928. Thereafter coal-dust explosions and fires were greatly reduced. Pulverized coal was prepared at this plant primarily for the reverberatory furnaces, but for several years it was also delivered to the converting plant, roasters and power-plant boilers by a system of auxiliary fans and delivery lines. During the period March 29 to April 8, 1929, one reverberatory furnace was fired with pulverized coal produced by an Aero, type J, unit coal pulverizer with a rated capacity of 5 tons per hour. This machine actually pulverized its rated capacity but the product was too coarse. After certain regulations, a her product was obtained but the pulverizer capacity decreased and this resulted in insufficient coal for efficient furnace operation. Table I gives a comparison of the average screen analyses of the pulverized-coal products from the impact-type unit pulverizer and the regular coal-plant installation. It was definitely proved that this size and type of unit pulverizer could not furnish sufficient coal of proper fineness to give smelting results comparable to that obtained with the regular coal-pulverizing plant. The coal from this unit pulverizer was so coarse that it did not ignite or burn properly and thus did not produce the proper heat for efficient smelting. During the latter part of 1929 and the early part of 1930, experimental work was conducted with a 7-ft. o-in. by 48-in. Hardinge conical ball-mill coal-grinding unit, which was installed alongside a furnace in the reverberatory building. Results obtained from the test run indicated that this unit would furnish sufficient coal of proper fineness for good smelting.

Jan 1, 1947

By Milnor Roberts

CORNWALL, a Mecca for metal miners the world over, is easily reached from the southern coast of England. Passengers who land at Plymouth or Southampton can connect with a fast train from London called the "Riviera express," which traverses the beautiful counties bordering the English Channel. In Cornwall the traveler soon notices the pits and stock-piles of white china clay, and the metal mines, both placer and hard rock. The deposits are associated with granite batholiths, of which there are four principal ones, each a few miles in diameter. Tin mines are especially worked in the granite near its borders and also in the immediately surrounding Paleozoic slates. Copper and lead are no longer of importance here but tin is being produced steadily from several mines, with arsenic and tungsten as by-products. At the close of the war the man-power available. for these mines had been reduced to one-third of normal, and only now is it again reaching full strength. As mining in Cornwall antedates the Christian era, even a Nevada prospector would have to admit that "she's a permanent camp." SUB-TROPICAL CORNWALL Redruth and Camborne are industrial centers of the tin mining industry, but more tourist hotels are found in neighboring resorts such as St. Ives, a quaint fish-ing town on the Atlantic-side of the peninsula of Corn-wall, where the numerous cats descended from those mentioned in the ancient riddle-rhyme about St. Ives now occupy every doorstep and wall. Another charm-ing resort. Penzance on the shore of the English Channel, is known by name to the public through the opera "The Pirates of Penzance," but is of especial in-terest to students of nature for its palm trees and other subtropical plants, which thrive owing to the nearness of the gulf stream, although the latitude is that of northern Newfoundland, Winnipeg, and the northern end of Vancouver Island. Among the industrial plants at Camborne are those of Holman Brothers, Ltd., where drills and other forms of mining equipment are manufactured. At the Corn-wall School of Mines, which specializes on the district, the staff has assembled excellent collections of local ores, which repay study by a visitor.

Jan 1, 1928

By C. S. Roberts

Microstructural studies of a Mg-10.3 pct Al alloy showed that discontinuous precipitation during aging multiplies the grain boundary area available for easy deformation in elevated temperature creep. An increase of strain rate for a 6.2 pct Al alloy at 400°F, where precipitation and creep are concurrent, caused an increase in the volume percentage discontinuously precipitated at the completion of the process. The relatively poor elevated temperature creep resistance of heat treated alloys of the Mg-AI-Zn type was explained in these structural terms. C resistance of the heat treatable Mg-A1 based alloys is poor compared to that of Mg-Ce based alloys. While the latter show a continuous precipitate, Mg-A1 alloys prefer a discontinuous precipitate at grain boundaries. '.:' It has been concluded that the excellent creep resistance of Mg-Ce alloys was primarily due to the continuous precipitation which especially localized at the grain boundaries.' The purpose of the present investigation was to obtain a parallel correlation, if such exists, between the poor creep resistance and the state of precipitation in Mg-A1 alloys. Discontinuous precipitation produces about three times as many true grain boundaries as originally existed. This microstructure would be expected to have a marked influence in creep, where quantity of grain boundary area is important. Experimental Procedure The two experimental alloys contained 6.2 and 10.3 pct Al. They were made from electrolytic magnesium by alloying under flux and casting in 3 in. diam permanent molds. The ingots were extruded into 1 1/4 x 1/8 in. flat stock under the following conditions: billet preheat 700°F (2 hr), container and die temperature 700°F, speed 3 fpm, and area reduction ratio 45:1. The creep specimens were machined from blanks which had been solution heat treated 24 hr at 770°F and aged 16 hr at 400°F. Attempts were made to control the grain size as closely as possible for extruded stock. The grain size after solution heat treatment was about two thousandths of an inch for the 6.2 and five thousandths for the 10.3 pct Al alloy.

Jan 1, 1957

By Rossiter W. Raymond

I DESIRE to call the attention of the Institute to a novel system of dredging, which, it seems to me, may prove applicable, not only to river and harbor improvements, but also to certain varieties at least of alluvial and diluvial gold mining; that is, river-mining, barmining, coast-mining, and any other similar operations now carried on by means of coffer-dams or dredging machines. The simple and effective method to which I refer is the invention of General Roy Stone, formerly an officer of volunteers, and at present a civil engineer, engaged under General Newton, of the United States Engineer Corps, upon the government works in New York harbor. General Stone has been, since September, 1878, in charge of operations upon Diamond Reef. This reef, lying between Governor's Island and the Battery, is one of the most dangerous in the harbor. Its position in the highway of navigation, and the fact that it is dangerous only to vessels of considerable draught and at certain stages of the tide, combine to increase the serious nature of the disasters which it has caused. The reef consists partly of rock in place, and partly of deposits of glacial clay, boulders, and pebbles, over all of which lies, or did lie until it was removed, the ordinary silt and rubbish of the harbor. As the purpose of the present paper has nothing to do with the special dimensions and other circumstances of this particular work, I describe those features only which are connected with General Stone's ingenious device. Various attempts have been made to remove the upper portion of Diamond Reef and secure a navigable depth at low tide. Some years ago Maillefert undertook to accomplish this by firing charges of high explosives, simply laid upon the surface. He accomplished some good in the removal of projecting points and ridges ; but as soon as the surface of the reef had become approximately level, his method was no longer effective. After the work had been taken up by the Engineer Corps, the well-known drilling-scow invented by General Newton was brought into action ; and, so long as holes could be bored and fired in solid rock, this process was effective enough. In the mixture of hard-pan

Jan 1, 1880

By J. O. Whiteley, C. Dietz

It is difficult to give a refining outline that may be followed for any and all combinations of the platinum metals; different combinations require different methods of attack. This paper does not pretend to go into all of the reactions of the metals of the platinum group, but will outline the commercial refining of platinum scrap. Typical Platinum Scrap As a concrete case, let us take 100 oz. of miscellaneous scrap, made up of jewelry scrap, dental scrap and laboratory ware. This lot will contain some platinum, palladium, iridium, ruthenium, rhodium, gold, silver and copper. The first problem is to get all of the metals in solution. If the scrap is principally platinum, palladium and gold, a treatment with aqua regia is the course to pursue; but if the scrap contains alloys high in iridium or ruthenium, aqua regia will act too slowly. In the case in hand, we are going to presume that we have scrap high in iridium and ruthenium, and proceed accordingly. Obtaining Residue A Place the scrap, together with six times its weight of granulated test lead, in a solid carbon crucible. This crucible may be placed inside a clay graphite crucible packed with charcoal, to prevent the excessive oxidation of the carbon crucible by the furnace blast. Place a tight cover on the carbon crucible; heat gradually to a good red heat and allow it to soak in the heat for 4 or 5 hr. After the leaded mass is cool, dissolve in dilute nitric acid (1-6) on a steam plate or sand bath. This dissolves practically all of the lead and most of the palladium, silver and copper, together with seme of the platinum and rhodium, and leaves the iridium, ruthenium, gold, and most of the rhodium and platinum as a finely divided residue. Siphon off the clear solution and treat the residue with another portion of dilute nitric acid to insure the solution of the lead and copper. The second nitric acid solution is added to the first, and the residue is filtered on suction and washed thoroughly with hot

Jan 1, 1928

TO WE BOARD OF DIRECTORS OF THE AMERICAN INSTITUTE OF MINING AND METALLURGICAL ENGINEERS Gentlemen:-The following report covers briefly some of the more important activities of the Institute during the year 1923. In my report for the year 1922, I drew attention to the falling off in membership of the Institute due to the depressed condition of the mining industry in several lines and the inability of many of our members to find profitable employment in mining or its associated branches. A number who were unemployed during 1922 established connections during 1923, but a still greater number have been forced to resign or drop their membership during 1923. Fortunately, the number dropped is not so great as in the previous year. The Employment Service conducted by the four Founder Societies bears witness to the trend in business. For the young men just out of college, there are plenty of opportunities at small salaries, there are plenty of opportunities for them as laborers; but for the mature members, those of experience, there are few calls. During the last eighteen months, our Employment Service has been able to place only six of our members out of every hundred engineers for whom it has found work. Another loss which this Society has suffered, but which is not felt so keenly by our sister societies, is in its foreign members. The A. I. M. E. has always had a large foreign membership, but of recent years exchange has been so heavily against many European and South American countries that a large number of members residing abroad have been compelled to relinquish their membership. Almost invariably these members express keen regret because of the necessity that confronts them, and almost invariably the writers express hope that present conditions will not last long and that they will soon be able to ask for reinstatement. Having stated the darkest side of the picture first, it may now be drawn to your attention that in spite of these losses the number of persons applying for membership was decidedly encouraging. From the quality point of view, the membership has not gone backward. The Membership Committee has declined to recommend many

Jan 1, 1925