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By Robert L. Akre

When Marco Polo visited China in the 13th century, no one knew what black powder was except the Chinese: they knew enough to make dazzling fireworks with it. But the realization that black powder could also do useful work came much later and, like all important discoveries, it altered the course of history. It was in the 14th century that black powder was first used to break rock in a very crude way: there were no drills and the powder was simply poured into cracks and exploded by setting it afire. Because its energy value was pretty low, the need for something more powerful was felt when the industrial revolution arrived.

Jan 6, 1976

By Earl Ingerson

BORE surfaces of used guns commonly show a pattern of cracks in various degrees of development. It has been suggested that these cracks may aid erosion by providing channelways for the gases, eventually leading to the tearing out of blocks of metal. Under the general studies of gun erosion conducted at the Geophysical Laboratory it appeared desirable to consider this factor, and to determine the resistance to surface cracking offered by gun steel and by various other materials that might be used in the bores of guns. METHOD AND APPARATUS In order to make such a determination it is necessary to have (I) an arrangement in which the surface to be studied can be subjected to conditions similar to those in a gun with respect to temperature, pressure (developed by explosion gases), composition of the gases and length of time the surface is exposed to the gases; and (2) a specimen that can be examined readily after any number of shots, and then fired again, if necessary. The first of these conditions can be met by using an explosion vessel designed by H. S. Roberts of the Geophysical Laboratory. Fig I shows a cross section of the apparatus. The "gun" G from which the charge is fired is made from the receiver of a caliber 0.30 army rifle, M1903, and the charges are prepared in caliber 0.30 cartridge cases. The test specimen S is held in place by a cone-shaped plug P and by a steel ,bridge B which is bolted to the outside of the explosion vessel on either side of the section shown. The plug, in turn, is held in place by a screw collar C. Maximum pressure is controlled by a brass rupture disk R. Part of the explosion gases flow past the two flat areas on S. st the two flat areas on S. Temperature and composition of gases, and the time before the rupture disk breaks, can be controlled by amount and kind of powder used, and pressure can be controlled by using rupture disks of different thickness. While the explosion vessel used was not designed so that temperature and pressure could be measured, in other vessels of closely similar size and shape containing proportionate charges of the same kind of powder as that used for standard testing procedure, values of 2700°K and 5000 psi were obtained. Since the orifices past the flat areas on the plug are small compared to the rupture disk hole (1:16), most of the gas goes out through the rupture disk when it breaks. The amount that goes by the plug depends on (I) the pressure attained before the rupture disk breaks and (2) the time it takes for this pressure to be built UP. The second condition (examination at will after any firing) is met by using for specimens short rods that have flat areas ground on opposite sides. These flat

Jan 1, 1947

For more than 100 years, the Republic of Chile has been one of the leading copper-producing countries of the world. Between 1877 and 1880 Chile accounted for over 50 pet of total world copper production. Today it has the world's largest known reserves of copper ore and a capability of producing over 600,000 tons per year. This capacity can and will be increased as the world demand for copper grows steadily during the remaining years of this century. The Potrerillos mine of Andes Copper Mining Co., a subsidiary of The Anaconda Co., was developed in the rugged, high Cordilleras in the early 1920's, and the townsite, concentrator, leaching plants, smelter, railroad, power and port facilities were completed so that it came into full production in 1927. Since then and until the closing o f the mine in June of last year, 1,762,192 tons o f copper were produced.

Jan 4, 1960

By Charles H. Morgan

THE case of Henry Cort comprises: (1) the nature of Cort's inventions;, (2) their value to England and to mankind,; (3) the remuneration received therefor by him or his family; and (4) the suitable permanent record and recognition of his services by the representatives of the art lie founded-a debt long over-due, and still unpaid. I. CORT'S INVENTIONS. Under this head, it is unnecessary here to enter into details. The facts have been repeatedly published, and a brief outline of them will be sufficient for my present purpose. . Henry Cort, born in 1740 at Lancaster, England, became a navy broker in. London about 1765, and gained from that business in about ten years. something more than £20,000, which lie devoted to perfecting the manufacture of iron, building a mill at Fontley, near Portsmouth, and prosecuting, between 1777 and 1783, the experiments which culminated in .his two patents, one for puddling iron and the other for shaping it by rolling between grooved rolls.: Careful study of the contemporary evidence, including Cort's specifications, the testimony (in act as well as word) of his business rivals, the public declarations of eminent authorities, and the history of the times, leaves no possible doubt that Cort was the real inventor, of

Mar 1, 1905

By John A. Church

In the year 1874, when the price of pig-iron was still high, that staple product became the subject of discussion in the newspapers and among those philosophers who are determined to know the "reason why" for all things. The object of the inquiry was to find out Why iron did not fall in price as much as some other things had fallen. Indeed, there seemed to be an impression that iron and gold ought to move on nearly parallel lines, for the fact was constantly brought forward that iron then cost twice as much as it did before the war, though gold had returned to within twelve or fifteen per cent. of its former value. After some time the papers, by what seemed to be nearly unanimous consent, reached the conclusion that the maintenance of high prices was the work of the furnace proprietors, who, as the result of their shrewdness, were pocketing enormous profits. No proof was given to support this opinion, and the figures of cost and sale that were produced were of the most general kind, and used in the most vague manner. Visiting the president of the Thomas Iron Company, whose great works at Hokendaqua and Catasauqua, in Pennsylvania, are so well known as the largest and among the best conducted in America, I found him quite willing to meet the vague suspicions of the newspaper wiseacres, by a publication of the figures contained in the furnace-books of his company. These were accordingly given to the world through the Engineering and Mining Journal, and attracted the general attention they so well deserve. Though my own name became connected with these statistics, from the fact that I used them as the basis for the first attempt ever made to calcalate the furnace economy of an American works, I can, without the suspicion of egotism, say that the statistics referred to are the most valuable contribution the literature of American blast-furnace work has yet received, for their interest is independent of personal considerations, and due entirely to the fact that they represent faithfully the details of practice in one of the most prominent American works. They are an exact transcript of the furnace-books, and form a body of accurate information of the greatest value to the metullurgical student. Their importance is shown by the fact that though the theoretical conclusions which I based upon them have been several times attacked, not one of my critics has made the slightest contribution to

By John A. Church

IN the year 1874, when the price of pig-iron was still high, that staple product became the subject of discussion in the newspapers and among those philosophers who are determined to know the "reason why" for all things. The object of the inquiry was to find out why iron did not fall in price as much as some other things had fallen. Indeed, there seemed to be an impression that iron and gold ought to move on nearly parallel lines, for the fact was constantly brought forward that iron then cost twice as much as it did before the war, though gold had returned to within twelve or fifteen per cent. of its former value. After some time the papers, by what seemed to be nearly unanimous consent, reached the conclusion that the maintenance of high prices was the work of the furnace proprietors, who, as the result of their shrewdness, were pocketing enormous profits. No proof was given to support this opinion, and the figures of cost and sale that were produced were of the most general kind, and used in the most vague manner. Visiting the president of the Thomas Iron Company, whose great works at Hokendaqua and Catasauqua, in Pennsylvania, are so well known as the largest and among the best conducted in America, I found him quite willing to meet the vague suspicions of the newspaper wiseacres, by a publication of the figures contained in the furnace-books of his company. These were accordingly given to the world through the Engineering and Mining Journal, and attracted the general attention they so well deserve. Though my own name became connected with these statistics, from the fact that I used them as the basis for the first attempt ever made to calculate the furnace economy of an American works, I can, without the suspicion of egotism, say that the statistics referred to are the most valuable contribution the literature of American blast-furnace work has yet received, for their interest is independent of personal considerations, and due entirely to the fact that they represent faithfully the details of practice in one of the most prominent American works. They are an exact transcript of the furnace-books, and form a body of accurate information of the greatest value to the metallurgical student. Their importance is shown by the fact that though the theoretical conclusions which I based upon them have been several times attacked, not one of my critics has made the slightest contribution to

Jan 1, 1876

By Emery R. Hayhurst

SILICOSIS has been described in a report of the American Public Health Association as a disease due to breathing air containing silica, characterized anatomically by generalized fibrotic changes and the development of miliary nodulations in both lungs, and clinically by shortness of breath, decreased chest expansion, lessened capacity for work, absence of fever, increased susceptibility to tuberculosis (some or all of which symptoms may be present), and by characteristic X-ray findings. ... The disease is divided arbitrarily into first, second, and third stages for convenience of description and possible compensation purposes. At least two distinct types of silicosis are recognized, acute and chronic. The acute form was reported as early as 1713, when a British patent for grinding flint by wet methods was granted because the dry powdered material "proved very destructive to mankind, so much that any person, ever so healthful, working in that business cannot possibly survive over two years."

Jan 1, 1936

By AIME AIME

ON May 5, the Washington, D. C., Section, A.I.M.E., devoted its meeting to the many-sided and perplexing question of mineral stock-piling for peace. Opening the symposium, Harry J. Wolf, of the War Production Board, outlined the problem under six heads: (1) Technical. Mechanical, chemical, or metallurgical importance of specified materials, emergencies that might arise, relative scarcity, and critical value of stock piles during emergencies. (2) Economic. Cost to Government, influence of Government stocks on commercial relationships and markets, effect of availability of items as a con¬structive influence on industry, Administration policies now and during postwar period. (3) Legislative. Need for immediate legislative action, need for legislation on postwar conditions as well as on current requirements, a constructive basic policy to prevent political manipulation. (4) Military. Consideration of re¬quirements and supplies bearing on national safety and needed for manufacture of equipment, and adequate reserves of scarce materials for research or experimentation by military agencies. (5) International. Interests of the United Nations in contradistinction to those of the United States; effects of nonisolation policy on nature, location, and administration of stock piles. (6) Negative stock-piling. Question of United Nations' legislation to prevent stock-piling by Axis nations after the war and who shall purchase stock-pile materials and during what periods.

Jan 1, 1943

By AIME AIME

WEST TEXAS, New Mexico and Northern Mexico form one of the most interesting regions in America for geologists and mining men and are full of points of historical and human interest for others. Including as the region does, a representative portion of the high plateau of Mexico, the front range of the Rocky Mountains and the great down-dropping plains of Texas, there is variety as well as interest in the geological and mining problems there to be studied. Gold and silver mining were the pioneer industries and are yet of high rank in importance. Among the papers to be presented at the El Paso meeting of the Institute this month will be two dealing with silver mining and ore treatment at the Shafter mine in Texas, that most un- usual property which has for so many years been the largest mining enterprise in its region. West Texas is now better known for its petroleum and gas, and in another paper will be described the problems involved in uding natural gas for smelting at the well-known El Paso smelter of the American Smelting and Refining Co. In still other papers, presented at the session sponsored by the West Texas Geological Society and cooperating organizations, the general geology of the region, the potash and the sulfur deposits will be de- scribed. At El Paso the refineries of the great com- panics will be available for visits.

Jan 1, 1930

By AIME AIME

THE following brief description of the main features of the, engineering work was prepared for the use of members of the American Society of Civil Engineers and members of the American Institute of Mining Engineers on the occasion of their visits to the tunnels at the time-of their respective. annual meetings in New York, January and February, 1905. DESCRIPTION. Those portions. of the Pennsylvania Extension into Manhattan and Long Island, lying east of the Terminal Station and west of the East River, have been designated as the " Manhattan ?Cross-town:. Tunnels." They traverse a section of the city second in importance only to the financial district, and one that includes the larger hotels, retail shops and theaters and the residences of many of the best known citizens. Section "D," consisting of twin tunnels for west-bound express and local passenger traffic, lies under Thirty-third Street from a point 400 ft. west of the west line of Sixth Avenue, eastward to the river shaft, situated in the block between Thirty-third and Thirty-fourth Streets east of First Avenue. Beginning at the east end, the tunnels are in separate excavations, leading westward from the subaqueous tubes, on a curve of large radius, gradually closing together until it is found more appropriate to drive them in a single excavation. At a point just west of Second Avenue they reach the tangent, aid from there westward lie directly under Thirty-third Street. At a point about 180 ft. west of the west line of Sixth Avenue, the center concrete-wall between the twin tunnels is omitted, and the excavation somewhat widened to make room for a third storage-track, and the tunnel continues to tile station portal in three-track section. Here reprinted through the courtesy of The United Engineering and Contracting Co. The half-tone blocks used for the illustration of this paper have been kindly supplied by the Chasmer-Winchell Press of New York, Pittsburgh and Cleveland.

Mar 1, 1908

By Joseph E. Pogue

The writer visited the Muzo emerald mines in July, 1915, and spent six days in their study. This paper embodies the results of his observations, plus information personally communicated by Robert Scheibe, Professor of Geology in the Mining Academy of Berlin, who at the time of the visit was completing a detailed field investigation of nearly a year's duration of the emerald deposits of Colombia. An elaborate account of this valuable work may be expected at a future date from the pen of Professor Scheibe.

Jan 1, 1917

By C. W. Purington, H. B. C. Nitze

The Kotchkar mining-district, known as the Kotchkar System, is situated in the Orenburg government, in Eastern Russia, in the great plateau- or steppe-country immediately adjacent to the eastern slopes of the Ural mountains. Its longer dimension is north and south about 27 miles, while in the widest (northern) portion the distance across is 22 miles. The district lies 40 miles southwest of Miass, a station of the Trans-Siberian railway, and half-way between this village and that of Troitsk. It contains also the not inconsiderable settlements of Kotchkar and Eosobrodskoit., the last a Kossak town. So far as explored, the district is known to contain from 300 to 400 auriferous veins. ? Although the topography is generally of an exceedingly flat character, the country is traversed by several small rivulets running from west to east, and flowing into the Sanarka and Kamenka rivers. Since 1844 placers have been worked in the district, but it was not until 1867 that veins were discovered, and these have been worked only since the impoverishment of the alluvial deposits. The deposit with which this paper especially deals is known as the Ouspensky mine, one of twelve owned by MM. de Zelenkoff & Cie., five of which are situated in the Kotchkar System. An opportunity of visiting this mine was afforded the writers, in eonnection with an excursion of the VII. session of the International Geological Congress; held in Russia during the summer of 1897. The mine is reached by a 40-mile '(troika" journey from the railway station of Bichkil, itself

Jan 1, 1899

By Geoffrey Gilbert

The material that forms the basis of this paper was collected in the spring of 1922, during a ten-day visit to Ducktown by the writer in the company of Prof. L. C. Graton. The time available for the work was far too short to allow anything like a thorough study of the deposits, and structural and stratigraphic questions, though they have an important bearing on the origin of the primary ores, were necessarily left untouched. Attention was focussed on the zone of oxidation and enrichment; and by devoting most of our time to the upper levels, open pits, and old workings, and examining the deeper levels only thoroughly enough to obtain a fair idea of the nature of the primary sulfide ore, we were able to make a reasonably complete survey of the various orebodies. With this field work for a background, the writer later made a study, in the Harvard laboratories, of the specimens obtained during the visit. As some of the facts brought to light by this study appear to be new, it seems worth while to set forth the outstanding features and a proposed explanation of them. Much of the Ducktown material that is obviously of greatest significance, as regards oxidation and enrichment, is soft and crumbly. Notwithstanding the desirability of gaining from such material all possible information as to its mineral composition and textural relationships, but little has heretofore been learned regarding it; but, by suitable preparation of this material in connection with the present study, it has been possible to examine it under the microscope without any disturbance of its texture and about as satisfactorily as if it were hard, fresh ore. The information thus gained has contributed measurably to the results set forth in this paper.

Jan 1, 1924

THE annual meeting of the Lake Superior Mining Institute was held on Sept. 7 and 8, Crystal Falls and Iron Mountain, Mich., being the principal centers of activity. Members of both institutes began assembling early, and by the evening of Sept. 6, some 60 had already arrived at Crystal Falls. The greater number arrived the following morning, however, and after the usual formalities of registration were attended to, the party were loaded into automobiles and set out on a tour of inspection of the mines near Iron River; some properties were passed through, and some were briefly visited to permit the inspection of any unusually interesting piece of equipment or detail of practice. The last stop of the morning was at the Caspian, Iron River, where the entire party was entertained at luncheon at the Caspian Club House. Both the food and the company were excellent, and as the weather was superlatively good (though the natives of the district modestly declared it was only ordinary autumn weather) the lunch was served on the lawn at the rear of the club, where the green turf, abundant flowers, and music by the band, added to the charm of good fellowship. The degree to which mining men have become addicted to golf was indicated by the large number of plus fours in evidence, whose wearers appeared just before lunch and disappeared immediately afterward.

Jan 1, 1928

By C. R. Fettke, Bela Hubbard

During the summer of 1916, while on a visit to the United States Agricultural Experiment Station at Mayaguez, Porto Rico, the writers were told by D. W. May, the director, that an occurrence of manganese ore had been reported from the mesa southeast of Mayaguez. A visit to the locality showed that the mesa is covered by a mantle of bright red soil resting upon serpentine. Here and there over its surface concretionary masses of limonite have been mashed out of this soil. These were apparently mistaken for manganese ore. On account of the similarity of this occurrence to the extensive iron deposits of northeastern Cuba, it was thought that a brief description based upon a two days'reconnaissance survey of the area mould be of scientific interest. Mayaguez is on the west coast of Porto Rico, at Mayaguez Bay, which is the third in importance of the harbors of the island. The city itself is about 3/4 mile inland on the low-lying plain at the mouth of the

Jan 1, 1920

By Geoffrey Gilbert

A study of specimens shows that the key to both oxidation and enrichment at Duck-town is the behavior of pyrrhotite, which is in part dissolved and in part replaced by marcasite. Enrichment takes place chiefly at the expense of marcasite. THE material that forms the basis of this paper was collected in the spring of 1922, during a ten-day visit to Ducktown by the writer in the company of Prof. L. C. Graton. The time available for the work was far too short to allow anything like a thorough study of the deposits, and structural and stratigraphic questions, though they have an important bearing on the origin of the primary ores, were necessarily left untouched. Attention was focussed on the zone of oxidation and enrichment; and by devoting most of our time to the upper levels, open pits, and old workings, and examining the deeper levels only thoroughly enough to obtain a fair idea of the nature of the primary sulfide ore, we were able to make a reasonably complete survey of the various orebodies. With this field work for a background, the writer later made a study, in the Harvard laboratories, of the specimens obtained during the visit. As some of the facts brought to light by this study appear to be new, it seems worth while to set forth the outstanding features and a proposed explanation of them. Much of the Ducktown material that is obviously of greatest significance, as regards oxidation and enrichment, is soft and crumbly. Notwithstanding the desirability of gaining from such material all possible information as to its mineral composition and textural relationships, but little has heretofore been learned regarding it; but, by suitable preparation of this material in connection with the present study, it has been possible to examine it under the microscope without any disturbance of its texture and about as satisfactorily as if it were hard, fresh ore. The information thus gained has contributed measurably to the results set forth in this paper.

Jan 3, 1924

Jan 1, 1892

By H.E. Brauer

Among the zinc base alloys used for casting in metal moulds, pnrticularly die casting, those alloys containing aluminum usually together with copper, are probably the most widely used. The reason lies in their desirable mechanical properties and the fluidity and absence of hot shortncss which facilitate ca,sting. Objection to the use of these alloys may be raised on account of the rather frequent instances of failure of a type variously described as disintegration, exfoliation and intererystalline corrosion. In all cases which have come to our kno~vlcdge where the conditionsof service were known, failure has occurred upon cxposurc to moisture and heat varying from a hot moist atmosphere to lligh pressure steam. RIoreover, the alloys described in all such roses contain impurities or alloying metals which the present authors have found to have enormous accelerating effects on intererystalline oxid:~t'ion in zinc-aluminurn alloys. Thus Williams1 experimented with an alloy containing a large percentage of tin exposed in Cuba. Baucr2 reports failure of a boiler plug containing over 1 per cent. of impurities, doubtless lead for the must part, and Rawdon's3 examinations were madc on an alloy containing 0.1 per cent. lead also exyosctl to thc Tropics. No thorough investigation of the nature and cause of this type of failure has been made heretofore, so far as the authors are aware, although Rawdon correctly classified it as internal oxidation. We have, therefore, carried out this investigation in order to det'ermine the exact nature of this phenonienon and the effect of other metals present as impurities or intentional additions in accelerating or retarding it. In the appendix we include a considerable amount of data which may be valuable in selecting an alloy combining good physical properties with high resistance to oxidation. At the time this work was undertaken the best available equilibrium *Investigator, Metal Section, Research Division, The New Jersey Zinc Company. 'H. W. Williams—Jour. Am. Inst. of AIet,als, Vol. 11, p. 221 (1917). 2o. Bauer—ZeiL, fiir i'vletall Kunde, Vol. 12, .No. 7, pp. 129-31 (1920). 3H. S. Rawdon—Trans. Am. Elcctrochcmic.al Society (1921).

Jan 1, 1923

By H. E. Brauer

Among the zinc base alloys used for casting in metal moulds, pnrticularly die casting, those alloys containing aluminum usually together with copper, are probably the most widely used. The reason lies in their desirable mechanical properties and the fluidity and absence of hot shortncss which facilitate ca,sting. Objection to the use of these alloys may be raised on account of the rather frequent instances of failure of a type variously described as disintegration, exfoliation and intererystalline corrosion. In all cases which have come to our kno~vlcdge where the conditionsof service were known, failure has occurred upon cxposurc to moisture and heat varying from a hot moist atmosphere to lligh pressure steam. RIoreover, the alloys described in all such roses contain impurities or alloying metals which the present authors have found to have enormous accelerating effects on intererystalline oxid:~t'ion in zinc-aluminurn alloys. Thus Williams1 experimented with an alloy containing a large percentage of tin exposed in Cuba. Baucr2 reports failure of a boiler plug containing over 1 per cent. of impurities, doubtless lead for the must part, and Rawdon's3 examinations were madc on an alloy containing 0.1 per cent. lead also exyosctl to thc Tropics. No thorough investigation of the nature and cause of this type of failure has been made heretofore, so far as the authors are aware, although Rawdon correctly classified it as internal oxidation. We have, therefore, carried out this investigation in order to det'ermine the exact nature of this phenonienon and the effect of other metals present as impurities or intentional additions in accelerating or retarding it. In the appendix we include a considerable amount of data which may be valuable in selecting an alloy combining good physical properties with high resistance to oxidation. At the time this work was undertaken the best available equilibrium *Investigator, Metal Section, Research Division, The New Jersey Zinc Company. 'H. W. Williams—Jour. Am. Inst. of AIet,als, Vol. 11, p. 221 (1917). 2o. Bauer—ZeiL, fiir i'vletall Kunde, Vol. 12, .No. 7, pp. 129-31 (1920). 3H. S. Rawdon—Trans. Am. Elcctrochcmic.al Society (1921).

Jan 1, 1923

By F. O. Blackwell

It is roughly estimated that some three hundred companies in the United States engaged in mining and the kindred arts now employ electricity in their operations. As all these plants have been installed within the last few years, it is evident that mining engineers have been quick to appreciate the great advantages of the use of electricity and adopt it for their many requirements. In

Jan 1, 1894