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By Horace Pops, J. F. Libsch

THE discovery of SAP alloys (sintered aluminum powders) by lrmannl has stimulated investigations in other alloy systems.23 Not only do such alloys have good room-temperature properties, but they maintain high strength after prolonged service at elevated temperatures. In addition, they show high structural stability, including unusually high recrystallization temperatures. These characteristics are secured by dispersion hardening. For this investigation, Zn-ZnO alloys were selected. Practically, the fact that commercially pure zinc recrystallizes near room temperature prohibits strengthening and hardening by cold deformation and therefore limits the application of zinc where mechanical strength is important. Similarly, the poor

Jan 1, 1961

FOR two days preceding the Colorado Mining Association annual meeting, officers representing all interests of the lead and zinc producers hammered away at remedies for the ills of the industry behind closed doors at the University Club in Denver. For once in the stormy history of the industry, large and small producers alike came to agreement with an automatic sliding scale stabilization import tax. The proposal set forth in full on the following page, is not new being merely an amplification of the tariff arrangement whereby tariffs are imposed when the price drops below ceiling. Its advocates claim that it is simple, automatic, and flexible. It will give stability to the industry without subsidies and since no government bureaus will be required to administer it, there will be no cost to the taxpayer.

Jan 3, 1953

By D. D. Homer, R. H. Cromwell

The Minas de Matahambre No. 2 shaft, vertical, four-compartment lined with steel sets and hardwood lagging, has been sunk 2057 ft. On account of rock structure, over-all cross-section dimensions are 23 by 6 ft. Certain sections have been concreted. Two compartments are for handling ore and men, one for supplies and men, and one for manway, cables and counterweight. Two 250-ton capacity skip pockets with air-operated gates and steel cartridge pockets have been installed underground. A steel "A" headframe, a 250-ton steel receiving bin, and skip-to-man-cage changing equipment have been provided. Skip capacity is 102½ cu. ft. The hoist is a Nordberg double-drum 10 ft. by 6 ft. 6 in. geared, electrically driven, with parallel grooving for 1-?in. cables. Maximum hoisting speed is 1600 ft. per minute. The motor-generator set, control panel, slip regulator and hoist accumulator are housed in the basement of the hoist house. The electrical equipment is General Electric. The direct-current hoist motor is 800 hp. Control is of the Ward-Leonard-Ilgner type. The motor-generator flywheel set, normal speed 720 r.p.m., consists of an 800-hp. induction motor, a 22-ton flywheel (dia. 117 in.) and a 650-kw. generator.

Jan 1, 1934

PRELIMINARY REPORT PUBLISHED FOR THE PURPOSE. OF INVITING SUGGESTIONS FOR, THE BENEFIT OF THE COMMITTEE 1 As a result of invitations extended by The American Society of Mechanical Engineers, a, number of associations of national scope have appointed representatives on a Joint. Committee on Standards for Graphic Presentation:- Below are the names of the members of the committee and of the associations which have co-operated in its formation. WILLARD C. BRINTON, Chairman,. American Society of Mechanical Engineers. [7 East 42nd Street, New York City.] LEONARD P. AYRES,Secretary, American Statistical Association. [130 East 22nd Street, New York City.] N. A. CARLE, American Institute of Electrical Engineers. ROBERT E. CHADDOCK, American Association for the Advancement of Science. FREDERICK A. CLEVELAND, American Academy of Political and Social Science. H. E. CRAMPTON, American, Genetic Association. WALTER S. GIFFORD, American Economic Association. J. ARTHUR HARRIS, American Society of Naturalists. H. E. HAWKES, American Mathematical Society. JOSEPH, A. HILL, United States Census Bureau. HENRY D. HUBBARD, United States Bureau of Standards. ROBERT H: MONTGOMERY, American Association of Public Accountants. HENRY H. NORRIS, Society for the Promotion of Engineering Education. ALEXANDER. SMITH,. American Chemical Society. JUDD STEWART, American Institute of Mining Engineers. WENDALL M. STRONG, Actuarial Society of America. EDWARD L. THORNDIKE, American Psychological Association.

Jan 10, 1915

By Jack Fox

On May 16, 17 and 18, 1871, the first meeting of the AIME was held in Wilkes-Barre, Pa. It was then that the objectives of the American Institute of Mining Engineers were set up. The first ones were to enable the Members of AIME, "comprising Mining Engineers and other persons interested in mining and metallurgy, to meet together at fixed periods for the purpose of reading papers upon and discussing subjects which have for their aim the economical production of the useful minerals and metals, and the safety and welfare of those employed in these industries, and to circulate among its members, by means of its publications the in- formation thus obtained." Now, 100 years later, the American Institute of Mining Engineers, which has now grown to be the American Institute of Mining, Metallurgical, and Petroleum Engineers, is still pursuing those objectives. Dues in 1871 were fixed at $10 per year. Now1 100 years later, the dues have risen to $20 per year. But in pursuing the objectives of the Institute, the services to members have vastly increased, as have the general costs of doing business-even "non- profit" business like ours.

Jan 1, 1971

By David R. Mitchell

IT is impossible to mention by name all the men and organizations that contributed to this volume. The original manuscripts of the chapters contained acknowledgments of various lengths, but space limitations make it impossible to print them. Suffice it to say that virtually everyone active in coal preparation in the United States contributed directly or indirectly to the contents of the volume. Special thanks are given to manufacturers of preparation machinery for their courtesy and willingness to furnish data, photographs and drawings. I am extremely grateful to Lupo Cinco, Alfred C. Arnold, Alfred E. Flowers, James M. Krese, J. H. Kelley, E. E. Vaccaro, E. J. Sandy, Edward Steidle, Jr., Joseph Fiedorek, David Scanlon, and Joseph T. Weber, former mining engineering students who contributed much of their leisure time for proofreading, checking references, and drafting, and without whose assistance it would have been difficult to prepare the manuscripts for publication this year. All sizes are for round-hole screens and tons are 2000 pounds, unless otherwise stated or indicated. Much of the manuscript material was prepared and edited during the war year of 1942 and I wish to offer my sincere thanks to contributors for their willingness to cooperate during these trying times. No doubt errors and omissions will be found in this book and for these I ask the readers' kindly indulgence.

Jan 1, 1943

ENGINEERS AVAILABLE (Under this heading will be published notes sent to the Secretary of the Institute of members or other persons introduced by members.) Member, Cornell M. E., graduate, aged 31, married. Will soon complete 2 years' engagement in the Russian oil fields. Eight years' practical experience in drilling for and producing oil. Can speak Russian fluently and some French and German. Open for engagement. Interview after August 15, in the United States. No. 299. Metallurgist, four years' experience in electric furnace operation on steel, ferro-alloys and smelting of ores, both practical and research, desires position as metallurgist or superintendent. No. 314. Member, technical mining graduate. 5 years' experience in coal and metal mines and construction work. Married. Aged 27. Employed at present. Interview in Salt Lake City or Denver. No. 316. Member, American, aged 39, married, desires position as superintendent or mine superintendent. 14 years' experience in opencut and underground work. 12 years' Spanish, Portugese, Cuban and Mexican labor. Fluent Spanish. Good training in first aid and safety first. Specialty of high explosives and steam-shovel work. Good costs. Go anywhere, but tropics preferred. References. Interview, New York or Philadelphia, No. 318.

Jan 10, 1916

By J. F. Lewis

Believing that one of the essential points in mining, as in all other business, is to know the expense incurred in each particular department, I have carefully kept an account with each department for the past three years; and, as it may be of interest to some of our members, I herewith present it to the Institute, reduced to per centages of the total yearly expense, showing the cost for materials, repairs, expenses, tools, team accounts, powder, oil, and fuel, also for labor under its several heads: 1875—Materials. 1875—Labor, Repairs,...040 Expenses,....016 Team,. .. .. .017 Machinery,. .. .055 Tools,..006 Repairs,. .. .027 Improvements,.....030 Washer,. .. .076 Oil ..008 Pit,.. 178 Powder,..,043 Dirt,.. 130 Fuel,. .325 Superintendence,. ..050 .485 .516 100.1 1876—-Materials. 1876-Labor. Repairs,. . • .. .043 Expenses,......012 Team,.011 Machinery,. .. .090 Tools,..005 Repairs,... 027 Improvements,.....007 Washer,. .. .085 I,. ...,015 Pit,.. 139 Powder,. .. .. .030 Dirt,.. 160 Fuel,...321 Superintendence,. ..078 .444 .559 100.3 1877—Materials. 1877—Labor. Repairs,......102 Expenses,......019 Team,..031 Machinery,. .. .050 Tools,..030 Rrpairs,. .. .046 Improvements,....,031 Washer,. .. .057 I,...009 Pit,.....179 Powder,...035 Dirt,.. 162 Fuel,...200 Superintendence,. ..054 .457 .548 100.5 Average for the three years 1875, '76, and '77. Materials. Labor. Repairs,...062 Expenses,...016 Team,..016 Machinery,. .. .065

Jan 1, 1879

On request of the Commissioner of Education, a small group of administrative professors of engineering and commerce from higher institutions near St. Louis met in conference with the Specialist in Commercial Education of the Bureau of Education on Feb. 22, for the purpose of discussing ways and means whereby the business of our country may be furthered through increased opportunity in our higher institutions for the preparation of engineers with business training. One or more representatives were present at this conference from the University of Minnesota, University of Illinois, Washington -University, University of Missouri, University of Iowa, Iowa State College, University of Kansas. It was recommended at this conference: First, That the Commissioner of Education appoint immediately a committee to consider commercial engineering in its various aspects and to prepare and approve one or more curricula in commercial and industrial engineering that can be recommended by the Bureau of Education for adoption in our colleges and universities. It was suggested that the committee consider the following curricula plans: First, That a minimum number of hours in business training be required in all engineering courses. Second, That a curriculum providing for a minimum of fifteen to thirty units in business economics be incorporated in all engineering courses and offered on an elective basis. Third, That a curriculum in commercial or industrial engineering, permitting full and proper emphasis upon engineering subjects, be offered in the School of Commerce with degree to be given in that school. Fourth, That a five-year combined engineering and commercial course he prepared.

Jan 5, 1919

Robert W. Hunt, Chicago, Ill.:—It has been my good fortune to know of this development of Mr. York's for some time, and I think he will permit me to say that this is not the first demonstration that he has made of his method for rolling difficult shapes, and which, as he has stated, had in the past been regarded as practically impossible. I have good reason to know that Mr. York has been successful on other lines, because I myself went through a period of professional disrepute for having reported favorably on his methods, which received discredit up to the time that it was practically demonstrated that his claims were true ones. Years ago Mr. York built a mill at Duluth, Minn., for the production of structural shapes, and notably of what might be called balanced beams—beams that did not have flanges of restricted width. His scheme was to produce beams with flanges so wide that they could be used in place of built-up beams. The mill, of course, went through the difficulties that such a mill would have to encounter. I mas called upon to make an examination of the property and report. These beams were rolled on a universal mill—a mill which would admit of various-sized sections without change of rolls. I was convinced that Mr. York could do it, and I so reported. Having received condemnation and ridicule for having taken that position, later on I was glad to find that Mr. John Fritz had come to the same conclusion, and had so reported. I concluded we both could rest content, while awaiting developments. Later still, as we all know, there was another difficulty that Mr. York met with—namely, that the architects or structural engineers would not accept his proposed sections. That is still a great difficulty in America. Later, the Grey mill came into successful operation in Luxemburg, producing such sections, which are being used in England and on the Continent. In fact, the whole process, both from a commercial and a mechanical point of view, is a success. The Bethlehem Steel Co., Bethlehem, Pa.,

Jan 1, 1907

By J. O. Nomland

DuRing the year 1939 the program of the California Arabian Standard Oil Co. in eastern Saudi Arabia consisted of drilling wells to increase the production of Dammam Dome. (This structure is also sometimes referred to as Dhahran Dome.) In addition, in other areas of the concession, wildcat wells are being drilled on geologically favorable structures. In the early wells drilled at Dhahran, production was at a depth of 2000 to 2200 ft. Since discovery of the "Arab zone" below 4300 ft., all of the later wells have been drilled to the deeper productive members. At present there are at Dhahran fivc wells in various stages of drilling or completion. In addition, 15 wells previously were drilled to the upper or lower zones. Although some of the early locations are exceptions, in general the spacing of the wells is at 3000 feet. Prospect testing consisted in drilling one well at Abu Hadriya and one at Ma'agala, about 100 miles northwest and 120 miles west of Dhahran. The first had attained a depth of 8655 ft. without encountering the main Darnmam productive zone, while the second was at a depth of 1372 ft. Both of these wildcat wells are on large dome structures. Production.—During the year 3,933,903 bbl. of approximately 35" gravity oil was produced, all from flowing wells. A part of this production was shipped in barges to the refinery at Bahrein. In early May a 40-mile 10-in. pipe line was completed to the deep-water terminal at Ras Tanura. The ceremony of first opening the valve for flow of oil into an ocean tanker was performed by King Abdulaziz Ibn Saud. Since that time tanker shipments have continued, both to Bahrein and to world markets. Only sufficient gas for camp purposes has been produced. Equipment.—A stabilization plant has been completed at Dhahran and plans have been made for a refinery at Ras Tanura. A modern camp is being built including power plant, central air-conditioning plant, radio station, employees' club and housing facilities for both married and single employees. Both the offices and dwellings are being air-conditioned. There is a hospital, with medical staff and nurses, providing facilities for both Saudi Arabs and Americans.

Jan 1, 1940

By J. O. Nomland

DuRing the year 1939 the program of the California Arabian Standard Oil Co. in eastern Saudi Arabia consisted of drilling wells to increase the production of Dammam Dome. (This structure is also sometimes referred to as Dhahran Dome.) In addition, in other areas of the concession, wildcat wells are being drilled on geologically favorable structures. In the early wells drilled at Dhahran, production was at a depth of 2000 to 2200 ft. Since discovery of the "Arab zone" below 4300 ft., all of the later wells have been drilled to the deeper productive members. At present there are at Dhahran fivc wells in various stages of drilling or completion. In addition, 15 wells previously were drilled to the upper or lower zones. Although some of the early locations are exceptions, in general the spacing of the wells is at 3000 feet. Prospect testing consisted in drilling one well at Abu Hadriya and one at Ma'agala, about 100 miles northwest and 120 miles west of Dhahran. The first had attained a depth of 8655 ft. without encountering the main Darnmam productive zone, while the second was at a depth of 1372 ft. Both of these wildcat wells are on large dome structures. Production.—During the year 3,933,903 bbl. of approximately 35" gravity oil was produced, all from flowing wells. A part of this production was shipped in barges to the refinery at Bahrein. In early May a 40-mile 10-in. pipe line was completed to the deep-water terminal at Ras Tanura. The ceremony of first opening the valve for flow of oil into an ocean tanker was performed by King Abdulaziz Ibn Saud. Since that time tanker shipments have continued, both to Bahrein and to world markets. Only sufficient gas for camp purposes has been produced. Equipment.—A stabilization plant has been completed at Dhahran and plans have been made for a refinery at Ras Tanura. A modern camp is being built including power plant, central air-conditioning plant, radio station, employees' club and housing facilities for both married and single employees. Both the offices and dwellings are being air-conditioned. There is a hospital, with medical staff and nurses, providing facilities for both Saudi Arabs and Americans.

Jan 1, 1940

PRESIDENT DOWLING'S ? ADDRESS I feel that it is a great honor to be invited to reply to this toast on behalf of the Canadian Mining Institute. I wish to thank you for your very cordial reception of the toast and for the sentiments expressed in your invitation to the Institute to cooperate in a series of joint meetings. It is an earnest of the mutual regard which the peoples of the two countries have for each other. We have been allies in a very great war and the feelings of good-will engendered by that alliance will survive, I believe, through the strenuous times of peace. The other nations of the alliance had through many changes in history, fought each other and for each other and had thereby gained a clear conception of the social aims and moral character of their peoples. With this knowledge came mutual trust-the one element necessary for united action or lasting agreement. On this continent the two peoples are drawn together by bonds of a common origin and, largely, a common language. No war has been necessary to force declarations of national aims on which to base terms of amity and now our peoples who had studied the arts of peace together have together passed through fire-drawn into the conflict by a like horror at the sacrilege of the crucifixion of the rights of humanity. Their courage and manhood has been tested at Ypres and Chateau Thiery by the great assayer war, and, together, with thankful hearts we see the triumph of right over night and better than ever know that we have the same conception of the government of the people for the people. We are met to celebrate the close of the association of our brethren it the front in the fight for freedom for the world-a freedom that to us hems natural but which to the majority of the allied nations is a heritage derived from the protest made by the American colonies against German ideas of government of which remnants had until then survived in Great Britain.

Jan 4, 1919

G. McMEANS*—This paper is a very good demonstration of the use of a new tool for the solution of industrial problems of a physical nature. To have solved this problem without the use of radioactive tracers would have required a far greater amount of investigation and work. The authors have described their work in such detail and in such a manner as to suggest the possibilities of the use of such tracer studies in the solution of many perplexing problems of industry. R. E. BREWER †—The authors are to be congratulated on this very excellent paper, which describes the results obtained by utilizing radioactive tracers in investigating the complicated reactions in the coking process. The paper has especial merit because the study was made under typical operating conditions in a commercial coke oven. Considering all the difficulties involved, the results obtained are excellent. My brief comments will relate primarily to the method used for determining the sulphur in the gas and to the value of the data obtained in stimulating further research. In discussing their results, the authors state (p. 17) that "Of the total sulphur charged to the oven in the coal 95 pct was accounted for in the coke and gas. Most of the sulphur unaccounted for is believed to have been lost in the gas, since the gas sampling system removed all the H2S but probably only part of the organic sulphur compounds present in the gas. Although sulphur in the acid-insoluble tar residue in the gas scrubbing bottles was determined and added to the total sulphur determination of each sample, it is doubtful whether an aliquot portion of tar for each sample was obtained." The reviewer believes that the authors might have obtained a better sulphur balance had they used an improved procedure for determining sulphur in the gas. The absorption train should have included a trap to remove the tar and am-moniacal liquor and a wash bottle containing 5 pct sulphuric acid to remove ammonia in the coke-oven gas before it entered the gas scrubbing bottles containing the ammoniacal cadmium chloride solution. Sulphur in the tar and

Jan 1, 1950

By A. B. Young

The difficulties encountered in the preparation of the lead smelter charge for the blast furnace and in the roasting and sintering of the ores, and the expert means taken for the preparation of these materials since the introduction of flotation concentrates into the lead smelter charge, have been described by W. H. Eardleyl and R. A. Wagstaff.² Function of Roasters and Blast Furnaces The lead smelter has first its roasters and its sintering devices, of which the primary object is the removal of sulfur from the ore or from the charge. The blast furnace follows; its function being the elimination of the gangue material left in the charge—the elimination of the insoluble, the iron, the zinc and the lime from the metallic lead. The secondary object is the separation of copper from the lead. A lead blast furnace is a sensitive apparatus. The materials composing the charge must be marshalled in certain proportions before they will make a fluid slag which will separate from the metallic lead. The silica, iron, lime and zinc must be put together in proportions that usually do not mist naturally in the ores, therefore fluxes are necessary. Function of the Flotation Cell The flotation cell—-speaking from the standpoint of a lead concentrate—has taken over part of the work hitherto performed entirely by either gravity concentration or the lead blast furnace. It has eliminated gangue from the concentrate and separated waste products from the lead. In so far as it has done that, it has usurped some of the function of the lead blast furnace; and it is much cheaper to run a flotation cell than a lead blast furnace. The effect in Utah, and it will be similar to effects in other districts. has been to remove a great deal of the gangue by means of flotation, whereas in the old clays it was eliminated by means of sme1ting. In this district, as in others, the insoluble content of the ores has been greatly out of proportion to the iron and lime content to make a proper slag

Jan 1, 1928

By L. Zwell, H. A. Wriedt

X-ray Lattice parameter and bulk density measurements were made at room temperature on solid solutions of nitrogen in purified a, iron, containing from 0 to 0.053 wt pct N. When nitrogen is dissolved in a, iron, the fractional increase in unit cell volume (X-ray diffraction) and the fractional increase in volume per gram of iron (bulk density measurement) are the same within experimental error. The two sets of results when averaged show that the unit cell edge of a, iron increases linearly by 3.2 X 10-2 A per wt pct N dissolved and that the partial gram-atomic volume of nitrogen at infinite dilution in a, iron is the same as it is in nitrogen-martensite, that is, 5.90 cm3. RECENT reviews17' of literature dealing with the lattice parameter of ferritic iron-nitrogen alloys indicate that the dilating effect of dissolved nitrogen on the bcc unit cell of a iron is not known with confidence. Five investigations3-7 either revealed no effect of nitrogen or were inconclusive. Among other investigations, where quantitative data were obtained, the results of Osawa and Iwaizumi8 indicate too large an effect, and those of Eisenhut and Kaupp9 show the lattice parameter of ferrite varying with the nitrogen content at concentrations far beyond the known solubility limit. It is not clear in Burns'10 data what value should be used for the lattice parameter of nitrogen-free ferrite in calculating the dilation. Burdese11 shares with Burns the shortcoming that the iron-nitrogen alloys were solution-treated and quenched with undissolved nitride present. The consequence is that the un- certainties in the solubility limit1 are added to those in the lattice parameter measurements when the variation of lattice parameter with nitrogen content is computed. For a system of such widespread interest, we felt that a new investigation was merited. Both X-ray diffraction and bulk density measurements were used to determine the dilation of the , a iron lattice by dissolved nitrogen. EXPERIMENTAL PROCEDURE Material. The bulk density and X-ray diffraction experiments were both made with specimens of a purified iron (denoted as "B iron")- from Battelle Memorial Institute. The impurity contents were as follows: As, C, Cu and Pb—50 ppm; Ag, Al, Co, Ga, 0, Ti-11 to 50 ppm; B, Be, Ca, Cd, Cr, Mg, Mn, Mo, N, Ni, S, Sb, Si, Sn, V, W-10 ppm or less. The vacuum-cast ingot was hot-forged and annealed. Pieces of the forged stock were machined and cold-rolled to give strip stock 0.08 and 0.002 in. thick for density and for X-ray measurements, respectively. Preparation of Specimens. Starting with a piece of the cold-rolled iron stock, the general sequence of operations, after an initial recrystallizing anneal, was to measure the density or lattice parameter, nitrogenize, remeasure the property, age or denitrogenize, and again measure the property. Duplicate analyses for nitrogen were made by a modified Kjeldahl method on portions of the actual density specimens and on pieces nitrogenized to equilibrium alongside the X-ray specimens. Annealing of the density specimens was performed by sealing the pieces with the as-rolled surfaces removed by filing into evacuated "Vycor" capsules and treating for 1 hr at 750°C followed by furnace cooling. (TO check the effect, if any, of annealing procedure, a specimen also was

Jan 1, 1962

By D. M. McFarland

A FEW years ago a novel electric detonator known as the split-second or millisecond delay electric blasting cap was introduced for use in quarry blasting. Regular electric blasting caps fired in series may be depended upon to fire within a millisecond or so from the first to the last in a series. Regular delay electric blasting caps are provided that fire one period after the other period in intervals of 1/2 to possibly 11/2 sec. Most split-second or millisecond delays are designed to fire one period after the other period in possibly 25 to 50 millisecond intervals. The ear is not capable of detecting time intervals of this magnitude. The primary thought at the time millisecond delays were introduced was to investigate the results on rock breakage by firing a line of holes in a quarry face so that charges in adjacent holes would not be detonated simultaneously. This could not be accomplished satisfactorily with regular delays. The time interval between successive periods of 1/2 to 1 sec was sufficient to permit considerable movement of the burden. If the burden of one hole was reduced to a great extent by the firing of an adjacent hole, the firing of the hole with the reduced burden would likely reveal this lack of confinement by a terrific report and wild throw of rock. In the early blasts with millisecond delays it was observed that instead of the usual sharp report, the blast had a muffled sound and vibration was not as perceptible as when simultaneous firing was used. Because many quarry operators were being threatened with injunctions or suits for damages by neighbors who claimed structural damage to their buildings, millisecond delays were tried extensively in quarries. In the majority of these trials, the results were very satisfactory. The seismologists recorded the ground movement created by many blasts and verified the initial observations that millisecond delays could be used to reduce vibrations appreciably. In the past few years the advantages of this principle of nonsimultaneous firing of the charges in blasts has become generally accepted. Today the quarry operator who has vibration troubles, inadequate breakage, and excessive backbreak and has not investigated the possibilities of millisecond delay blasting is ignoring a remedy that has proved satisfactory for many. His complacency may be costing him money. Because of the results attained in quarry blasting, it was logical that millisecond delays should be tried in construction work such as in road cuts. As formations in this type of work are likely to change rapidly with advance of the cut, it is more difficult to evaluate results than in quarry blasting. However, this improved control over timing has been beneficial in limiting throw, promoting fragmentation, and reducing overbreak. In blasting near buildings the reduction in vibration and in throw has been especially helpful. As blasters employed in construction work learn what may be accomplished by closer control over the time of firing of explosives charges, more and more millisecond delays are being used to supplant instantaneous electric blasting caps. Improved Fragmentation Underground With this background of promising results, it was not surprising that millisecond delays should go underground. In limestone mining use of millisecond delays as compared with use of cap and fuse or electric blasting caps showed improved fragmentation in stopes and in slabbing operations. Then an opportunity developed to use millisecond delays in some tunnels being driven in a limestone mine (fig. 1). Using the normal charge employed and merely substituting three millisecond delay periods for three regular delay periods, there was a noticeable difference in the appearance and the position of the pile of rock after a blast. A greater portion of the face was exposed, the crest of the pile was farther from the face, and the pile was heaped high along the center line of the tunnel leaving room to walk along the ribs to the face. Fragmentation was appreciably increased. It gave the impression that the slabs had been thrown against each other with tremendous force, promoting the movement of the broken rock along the center line of the tunnel away from the face. Because the drilling and the charge weights were unchanged, the evidence was convincing that the difference in timing was responsible for the difference in results. Probably a greater portion of the energy from the explosives had been expended in doing useful work on the rock. Zeros followed by two periods of millisecond delays were used in the V cut and in two slabs to either side of the cut in this simple round. When millisecond delays, substituted period for period for regular delays, are first tried in a drift round in a mine, and the usual charge of explosives

Jan 1, 1951

By D. M. McFarland

A FEW years ago a novel electric detonator known as the split-second or millisecond delay electric blasting cap was introduced for use in quarry blasting. Regular electric blasting caps fired in series may be depended upon to fire within a millisecond or so from the first to the last in a series. Regular delay electric blasting caps are provided that fire one period after the other period in intervals of 1/2 to possibly 11/2 sec. Most split-second or millisecond delays are designed to fire one period after the other period in possibly 25 to 50 millisecond intervals. The ear is not capable of detecting time intervals of this magnitude. The primary thought at the time millisecond delays were introduced was to investigate the results on rock breakage by firing a line of holes in a quarry face so that charges in adjacent holes would not be detonated simultaneously. This could not be accomplished satisfactorily with regular delays. The time interval between successive periods of 1/2 to 1 sec was sufficient to permit considerable movement of the burden. If the burden of one hole was reduced to a great extent by the firing of an adjacent hole, the firing of the hole with the reduced burden would likely reveal this lack of confinement by a terrific report and wild throw of rock. In the early blasts with millisecond delays it was observed that instead of the usual sharp report, the blast had a muffled sound and vibration was not as perceptible as when simultaneous firing was used. Because many quarry operators were being threatened with injunctions or suits for damages by neighbors who claimed structural damage to their buildings, millisecond delays were tried extensively in quarries. In the majority of these trials, the results were very satisfactory. The seismologists recorded the ground movement created by many blasts and verified the initial observations that millisecond delays could be used to reduce vibrations appreciably. In the past few years the advantages of this principle of nonsimultaneous firing of the charges in blasts has become generally accepted. Today the quarry operator who has vibration troubles, inadequate breakage, and excessive backbreak and has not investigated the possibilities of millisecond delay blasting is ignoring a remedy that has proved satisfactory for many. His complacency may be costing him money. Because of the results attained in quarry blasting, it was logical that millisecond delays should be tried in construction work such as in road cuts. As formations in this type of work are likely to change rapidly with advance of the cut, it is more difficult to evaluate results than in quarry blasting. However, this improved control over timing has been beneficial in limiting throw, promoting fragmentation, and reducing overbreak. In blasting near buildings the reduction in vibration and in throw has been especially helpful. As blasters employed in construction work learn what may be accomplished by closer control over the time of firing of explosives charges, more and more millisecond delays are being used to supplant instantaneous electric blasting caps. Improved Fragmentation Underground With this background of promising results, it was not surprising that millisecond delays should go underground. In limestone mining use of millisecond delays as compared with use of cap and fuse or electric blasting caps showed improved fragmentation in stopes and in slabbing operations. Then an opportunity developed to use millisecond delays in some tunnels being driven in a limestone mine (fig. 1). Using the normal charge employed and merely substituting three millisecond delay periods for three regular delay periods, there was a noticeable difference in the appearance and the position of the pile of rock after a blast. A greater portion of the face was exposed, the crest of the pile was farther from the face, and the pile was heaped high along the center line of the tunnel leaving room to walk along the ribs to the face. Fragmentation was appreciably increased. It gave the impression that the slabs had been thrown against each other with tremendous force, promoting the movement of the broken rock along the center line of the tunnel away from the face. Because the drilling and the charge weights were unchanged, the evidence was convincing that the difference in timing was responsible for the difference in results. Probably a greater portion of the energy from the explosives had been expended in doing useful work on the rock. Zeros followed by two periods of millisecond delays were used in the V cut and in two slabs to either side of the cut in this simple round. When millisecond delays, substituted period for period for regular delays, are first tried in a drift round in a mine, and the usual charge of explosives

Jan 1, 1951

THE Council of the Geological Society of America has named its gold medal after R. A. F. Penrose, Jr., who recognized the need of such an award and supplied the endowment. The medal is to be awarded for achievement in pure science and may be given to a worker of any race or nation. Mr. Penrose, whose own professional work has been mainly in applied geology, had previously established a medal fund for the Society of Economic Geologists. This was awarded to T. C. Chamberlin at the meet-ing of that Society at Cornell University in 1924. The new medal is to be given on the recommendation of the G. S. A. Council, but not necessarily every year.

Jan 4, 1927

By D. L. Everhart

The search for new deposits raises two important questions: Where did the metallic ions that formed the orebodies come from? What processes and geologic factors were involved in ore replacement? A review of the wide geological variety of recent uranium discoveries tells how these questions are being answered. SOONER or later intelligent exploration for uranium leads to these questions: Where did the metallic ions that formed the orebodies come from? What processes and geologic factors were involved in ore replacement? These matters, of course, make a big difference in how best to look for orebodies. Before these questions are discussed it might be well to point out other factors bearing on the subject. The whole business of uranium exploration is only a little over ten years old, participation by the public is only about six years old, and real interest and activity by more than a few large mining companies has arisen only in the past two or three years. Throughout this short period, uranium exploration has been affected by the unique influences of necessary security measures and by division of the overall job into individual projects by a large number of specialists in diverse fields. This has meant that a normal interchange of information on the nature of uranium deposits has really only just begun. Compared to the vast amount of published studies on iron, copper, lead, zinc, and gold deposits over the past 50 to 75 years, current knowledge of uranium deposits is in its infancy and much of the pertinent information is still scattered about in a number of unpublished sources. The volume of reports on all phases of uranium exploration is now beginning to mount at a remarkable rate, and geologists with widely varying specialized backgrounds in uranium geology are engaging in spirited debates over the origin of uranium and the relative importance of geologic controls of various deposits. One of the most interesting features of known uranium deposits of the world is the wide variation, see Table I, in character and geologic environment. It should be noted that many types became prominent during 1953. The davidite-bearing veins of Radium Hill, South Australia, are almost unique, although the same mineral occurs in a different kind of deposit in Mozambique. Recent studies indicate that brannerite disseminated in the granite near Cracker's Well, South Australia, may soon constitute uranium ore. Basalt has been added to the list of favorable host rocks in the Northern Territory of Australia. Basalt is also the host of the pitchblende veins of the Martin Lake deposit, Beaverlodge district, Saskatchewan. The truly remarkable rich and extensive Steen deposit near Moab, Utah, is of the uraninite-vanadium oxide type. Secondary hydrous uranium arsenates and phosphates constitute the uranium minerals in the disseminated deposits of the Wind River Basin, Wyo., a new district discovered in the summer of 1953. Uranium minerals in shales adjacent to fractures were newly reported in New Mexico and several other parts of the world during the year. The well-known important uraninite dissemination in the Rand conglomerates of South Africa has a counterpart, as discovered in the summer of 1953, in the Mississagi quartzite and conglomerate of the Blind River district, Ontario. Gunnar deposit of the Lake Athabaska district, Saskatchewan, consists of uraninite in both granite and sedimentary gneiss beneath a granite cap, and large new orebody of the Eldorado Co. in the same general area follows a preferred stratigraphic horizon in schists. Uranium is, generally speaking, a very soluble and ubiquitous element. It occurs in at least two valency states and for this reason is not easily tied down in natural solutions. As Gruner' has pointed out, it is probable that uranium starts in the hexava-lent state in nearly all solutions instrumental in its transfer. It is believed that under oxidizing conditions the uranium moves in solution as the uranyl ion, UO. In solutions ranging in pH from 1 to 5, the uranyl ion is most commonly in association with

Jan 1, 1955