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By AIME AIME

S ULFURIC acid made in the United States during the last four years has averaged approximately 7,000,000 tons of 50" B6 acid a year. This is double the production of the year 1913. About 66 per cent of the acid is made from sulfur, 16 per cent from pyrite, 13 per cent at copper, lead, and zinc smelters, and the remainder from miscellaneous sources it her the chamber process or the contact process, (at some plants both) is used. In 1923, the contact process accounted for nearly 30 per cent of all the sulfuric acid made in this country and since then it has been increasingly employed. It was first introduced here in 1898, and has always .proved less expensive than the chamber process for the manufacture of .acid of high concentration and purity, but the latter produces acid of low strength suitable for many industries.

Jan 1, 1929

By Frank Firmstone

IN 1871, two furnaces at the Glendon Iron Works, which had been blown out on account of the "coal strike," were altered from the open-top plan with side flues for collecting the gas, to closed tops with cup and cone. In one furnace the suppression of the side flues permitted a considerable alteration in the profile, but in the other (No. 5) no change in this respect was made; the side flues were simply bricked up and new ones cut through the sides close to the top. This furnace was in blast over four years, and we can, therefore, form a pretty good idea of the effect of the alterations on the furnace process. The principal dimensions are; Height 72'; greatest diameter, 18'; diameter at tuyeres, 8'; diameter of top, 10'; diameter at stock line (point at which the top of the materials is kept), 11'; cubic contents, 11,900 cubic feet. The table below shows the average results for periods of twenty-six weeks each. 1st, of the open-topped furnace; 2d, of the furnace with the first charger used, which was an ordinary cup and cone (diameter of cone 5' 2") 3d, with the charger used ever since, a "double" cone 7' 5" diameter outside, having a central opening 3' in diameter. The diagram (Plate II) shows the daily variations, in the grade of the irons for the same periods.* * In calculating the average grade of each day's iron, each twelve hours was taken by itself whenever more than two kinds of iron were made in the 24 hours, and the diagram drawn accordingly. By counting, it will be found that there were more such days with the single cone than with the "double" cone, and more with this than with the open top. † Anthracite.

Jan 1, 1876

Jan 1, 1963

By Leonard Austin

WHAT Colonel Dwight says regarding the treat-ment of oxidized ores1 holds true also of the silver-lead smelting operations in Utah. The ore sought for was such as would, with appropriate fluxes, yield slag, and "lead bullion," as the lead reduced from the ore and carrying its gold and silver, was called. No matte, and probably little or no speiss, was yielded, and hence there was nothing to roast, either of ore or matte. But, by 1880, when I first took hold in smelting, there was quite a production of matte at the works of the Ger-mania Smelting and Refining Co., Utah, because, by that time, ores containing some pyrite and galena were being smelted. This was due, as at the Grant Works, Denver, to the more attractive price paid for the treatment of such ores. The matte, containing about 5 per cent. copper, was accordingly heap-roasted and returned to the blast furnace for the recovery of its contained metals. By this time there had been built a long-bedded, hand-rabbled reverber-atory roaster with a hearth of about 40 by 10 ft. in size, and in this matte and ore, crushed at the sampling mill, was treated. When, in 1892, I took control of this works, called& now the Germania Lead Works, three other roasters had been added, but the prac-tice of heap-roasting continued. This had the merit of needing no equipment, and of doing good work, because the pieces that were imperfectly roasted went back upon the next roast heap. At this time, when some suitable lump ore was obtainable, I roasted in heaps, in a satisfactory way. By 1892, the Bruckner cylinder roaster had been installed, which, compared with the reverberatory roaster, reduced labor. As such a cylinder revolves, a talus of ore is formed within it and at the same time fresh surfaces are exposed to the air, but the trouble was that the air did not reach to the bottom of the cylinder. This we corrected by placing a steam jet at the fire-box end, to project the air down-ward upon this stagnant ore, thus increasing the speed and completeness of roasting without at the same time increasing dust formation. The firing, if skilfully done, gave a somewhat sintered product, but with certain ores a slight access of heat over the normal would cause accretions to form within the cylinder near the fire end. These could be cut off by running back the fire box and barring off the crusts. It was in 1895 that the Bruckner cylinders at the Arkansas Valley plant, Leadville, were giving unsatis-factory service and I was called in to investigate. The steam jet was put in use as at the Germania Lead Works, but we found that, due to the altitude (10,500 ft.), combustion was feebler than at sea level or even at 4000 to 5000 ft. Later it appears, as Colonel Dwight states, that R. D. Rhodes and Mots sought to increase the air supply by admission through perforated tiles, but the trouble was due to the air itself.

Jan 8, 1922

By P. R. Bradley

NO thought had been given to deep level mining at the Alaska Juneau mine prior to 1930, but in that year a prospect winze was started and continued for 1000 ft. vertically below the main haulage or adit level. The point at which this winze was started was selected entirely by the prevailing physical conditions, such as proximity to established workings, convenience, and the presence overhead of a substantial pillar of dimensions sufficient to lo¬cate the sheave wheel and loading pocket. It was, therefore, with some surprise that the unusually high-grade ore found just below the collar of the winze persisted, with certain vari¬ations, to a full depth of 1000 ft. vertically. Likewise this unusually high-grade ore was found to persist on the various crosscuts driven on levels at 200-ft. vertical intervals. To be brief, this deep level work found richer ore than any yet found in the mine over like areas, and inasmuch as the area was sufficient to plan for extensive deep level mining, plans for such work were given extended consideration.

Jan 1, 1936

By AIME AIME

THE fall meeting of the Petroleum Division, held at Tulsa, Okla., on Oct. 11 to 14, devoted two days to technical sessions and two to field excursions. A representative attendance of 250 to 300 engineers and operating officials engaged in oil production marked the sessions and paid close attention throughout to a notable series of highly technical papers. Restricted as the program was to consideration of production problems only, the time proved too short for discussion or even the presentation of the 20 papers submitted. Much informing and pertinent discussion none the less took place, and the sentiment was general to the effect that the meeting was one of the best ever held by the Division. The meetings were held in the auditorium of the Municipal building and local arrangements were well looked after by the Mid-Continent Section of the Institute and the Oil and Gas Association. The combination of the three organizations served to bring together engineers and operators most usefully. F. Julius Fohs, chairman of the Division, presided at the sessions on Monday. Tuesday morning John M. Lovejoy of the local section took over this responsibility in the absence of T. E. Swigart, who was detained in California. The afternoon session was presided over by A. G. Heggam of the Oil and Gas Association and the Tuesday evening banquet by W. C. Franklin of the same organization.

Jan 1, 1926

By H. M. Chance

The iron-ore deposits of the Hartville district are located near the new town of Guernsey, about 100 miles north of Cheyenne. The writer has been familiar with them since 1887, having visited the district several times for different clients— his last examination having been made in November and December, 1897. The deposits extend in a general N.E.-S.W. direction from a point in Section 33, Range 65 W., Township 28 N., on the west side of Whalen cañon, through Sections 4, 5, 6, 7 and 8 of Township 27 N. in the same Range, and over into Sections 1 and 12 of Township 27 N., Range 66 W. General Characteristics. The ore is a remarkably pure red hematite, extremely low in phosphorus, and carrying a small percentage of silica, as shown by analyses given below, and similar in many respects

Jan 1, 1901

By Carl E. Swartz

For many years kettles used in the melting and refining of lead and other nonferrous metals and alloys have been made of cast iron. The logic of this probably lies in the fact that cast iron has been known as a material of construction for vessels of this type much longer than steel, and satisfactory fabrication from it has been more easily accomplished and better understood. As the capacity of lead refineries has increased, it has been only natural to increase the size of kettles. Today kettles of 150 to 250 tons are not uncommon. As the size of the kettles increased and better shapes were designed, the uniformity of material of construction became more important. Records kept over comparatively long periods of time have shown that the length of service of kettles has not been uniform. Many causes contribute to this and the importance of each has not yet been evaluated. Kettle design, kettle setting, method of firing and material of construction have been changed from time to time to obtain better service, but the variation in length of service is still great. A kettle may fail during the first few heats or may last through more than one thousand heats. The purpose of this article is not to present the conclusions of a finished piece of research on kettle manufacture and use, but to present a series of observations made over considerable time in the hope that others will publish data and that all may be correlated into a logical scheme which will result in better service and longer kettle life.

Jan 1, 1931

By Carl Swartz

FOR many years kettles used in the melting and refining of lead and other nonferrous metals and alloys have been made of cast iron. The logic of this probably lies in the fact that cast iron has been known as a material of construction for vessels of this type much longer than steel, and satisfactory fabrication from it has been more easily accomplished and better understood. As the capacity of lead refineries has increased, it has been only natural to increase the size of kettles. Today kettles of 150 to 250 tons are not uncommon. As the size of the kettles increased and better shapes were designed, the uniformity of material of construction became more important. Records kept over comparatively long periods of time have shown that the length of service of kettles has not been uniform. Many causes contribute to this and the importance of each has not yet been evaluated. Kettle design, kettle setting, method of firing and material of construction have been changed from time to time to obtain better service, but the variation in length of service is still great. A kettle may fail during the first few heats or may last through more than one thousand heats. The purpose of this article is not to present the conclusions of a finished piece of research on kettle manufacture and use, but to present a series of observations made over considerable time in the hope that others will publish data and that all may be correlated into a logical scheme which will result in better service and longer kettle life.

Jan 1, 1931

By S. R. Elliott

THE Spies mine is located in the eastern half of the northwest quarter of section 24-43-35, near the village of Iron River, Mich., and is operated by The Cleveland-Cliffs Iron Co. Speaking generally, the jasper hanging walls of most of the deposits in the Iron River district dip at a steep angle and are exceedingly strong, standing without caving, even after mining has been continued for years and after large excavations have been made. The ore is fairly hard and tough and contains no slippage faces. It occurs in large masses, which are often egg shape, with the smaller end down, and can be mined in, open stopes without the use of timber. The common system employed in the district is the shrinkage stope, or some modification of it. The Spies system was developed to utilize the advantages of the open-stope method and to avoid the disadvantages of the shrinkage stope. The Spies shaft was sunk to such a depth that the bottom, or third level, was in rock at a short distance below the bottom of the orebody, the shape and extent of which had been previously determined by diamond drilling. This is shown in plan and by the ore contours at the first, second, and third levels in Fig. 1, and in section in Figs. 2 to 7. In order to provide the necessary mills and raises, three parallel crosscuts were driven on 25 ft. centers on the bottom level. Drifts on the second and first levels were driven to the orebody and followed the foot wall in a southerly direction to the end of the ore. In crosscut 3, Fig. 1, raises 30, 40, 50, and 60 were carried up on the foot wall and holed into the second level, and were ultimately carried up and holed into the first level. These foot-wall raises carry the pipes and ladders, provide a means of ventilation, and furnish safe communication to all working places in the stope.

Jan 3, 1922

By A. E. Harnsberger

IT is obvious that details such as the physical and chemical properties and methods of heat-treating of the materials mentioned must be omitted in a paper on the subject of materials used in oil-refinery pumps1. Only sufficient identification is given to enable the reader to find additional information from already published data. Also, the subject covers many operating conditions, but only the most important services can be discussed here. To the oil refiner, the pumping equipment is of vital interest. Practi-cally every refinery operation, from the charging of crude oil to a dis-tillation unit to the shipping of refined products, involves some form of pumping machinery. Intermediate refining stages involve a great variety of pumping machinery to carry out successfully the aims of the refinery technologist. Temperatures at which oils are handled vary from -50° F. to 900° F. Pressure may vary from subatmospheric to 2000 lb. per, sq. inch. The selection of the proper materials involves a careful consideration of the conditions under which the particular pump must operate. The four most important considerations are temperature, pressure, corrosion, and abrasion or wear. Consideration of temperature may be divided into three parts: (1) extremely low temperatures of the order of -50° F.; (2) temperatures at atmospheric or slightly above; (3) temperatures from 200° to 900° F. Pressures fall into two groups: (1) pressures reached by ordinary trade pumps of the order of 200 lb. per sq. in., (2) extreme pressure conditions involving pressures as high as 2000 lb. Noncorrosive and corrosive oils can be treated differently. Under the latter falls corrosion in the presence of water, which will occur up to 250° F. The second type of corrosion occurs in high-temperature pump-ing equipment, with temperatures from 450° to 900° F., largely caused by sulfur compounds. There are also other corrosive conditions met with

Jan 1, 1935

Human engineering was the keynote of the thirty-ninth annual meeting of the American Society of Mechanical Engineers, which was held in New York, December 3-6. This note was sounded by President Charles T. Main in his address at the opening session and was carried through by all the speakers. In his survey of the year's work, he said that more than 6000 names of engineers were furnished the Government for filling a wide variety of positions. In addition to the 1400 members in service, two members of the council of the society are in uniform in France and one, as a distinct war service, is in charge of one of the largest shipyards. After giving other ways in which the Society has helped the Government, President Main called attention to the necessity for thoroughgoing efforts to increase production and the settlement of questions involving industrial relationships. At the following meeting, President Adams of the American Institute of Electrical Engineers called attention to the necessity of meeting labor in a progressive way, facing labor questions fairly and squarely, as the real interests of labor cannot be separated from those of the engineer. Charles E. Knoeppel, discussing "Industrial Organization as It Affects Executives and Workers," said the problem of the cost of living might be settled in two ways: 1, there must be more producers, and 2, there must be a greater amount supplied by those now producing. The first solution is practicable, he said, if labor is allowed shorter hours, better conditions, and a remuneration that will attract workers. The second can be employed by eliminating waste, standardizing conditions, setting fair tasks, and allowing men to earn an amount that will compensate them for' their skill and cooperation. Dudley R. Kennedy of Philadelphia, employment manager of the American International Shipbuilding Corporation, said the human-engineering phase of the country's industrial development had generally been overlooked. "We hardly yet know what competition means; we will learn it within a few years. Permit me to prophesy that the executive of the next decade will be the man who best knows men. He will be an originator, a handler of men as individuals, a handler of men in the mass, a leader not a driver, a very human man. The science of human engineering is here to stay. The study of human characteristics is the most enduring, as well as the most fascinating in the world, and still the most complex."

Jan 1, 1919

A development drilling and bulk sampling program should furnish the following information: (1) geology of the mineralized zone, (2) quantitative data on grade and tons of material within pertinent cutoff limits, (3) physical size and shape of the deposit and areas underlain by waste as well as ore, (4) mineralogical and metallurgical characteristics of the ore, (5) physical characteristics of the ore, (6) bulk samples for metallurgical testing and grade, (7) data on factors that affect mining operations, such as ground water and ground conditions. The method and equipment best suited for a particular drilling job depend upon the geologic features of the mineral deposit to be tested.

Jan 10, 1967

1. What Is a Rock Burst? . . . . 569 Jack Spalding . . 569 A. F. Robertson . 569 W. R. Crane . 569 G. S. Rice......569 P. J. Shenon........... 569 L. C. Graton........... 569 2. What Are the Causes of Rock Bursts? 573 Jack Spalding..........573 A. B. Yates and P. J. Shenon 574, 578, 592, 596 A. F. Robertson . . . . . 575, 595 W. R. Crane. ... 579 G. S. Rice.........582 Oscar Weiss .........582 P. B. Bucky..........582 P. H. Bird.....588, 592, 593, 595 M. K. Hubbert.........593 G. Wheeler.......... .593 B. F. Tillson........593, 595 T. T. Read............594 3. How Can Rock Bursts Be Prevented?. 597 Jack Spalding..........597 A. B. Yates and P. J. Shenon ... 598 A. F. Robertson.......599 W. R. Crane....... .602 G. S. Rice............602 Page 4. How Can Rock Bursts Be Predicted?. 602 Jack Spalding.........602 A. F. Robertson.......602, 603 A. B. Yates and P. J. Shenon ... 602 W. R. Crane......602 G. S. Rice......602 B. F. Tillson...........603 5. How Can Rock Bursts Be Controlled? 603 Jack Spalding..........603 A. F. Robertson.......603 W. R. Crane...........604 A. B. Yates and P. J. Shenon 604 Oscar Weiss........605 G. S. Rice......- 604, 609 R.D.Hoffman..609, 610 R. D. Hall..........609 R. H. Cromwell . . 609 P. J. Shenon...........609 P. B. Bucky......609, 611 B. F. Tillson.........609, 611 A. B. Yates...610, 611 P. H. Bird.......610 6. General Discussion........ 611 Jack Spalding.......... 611 R. D. Parker....... . 616 C. Baring Horwood........ 618 P. B. Bucky........... 619 Foreword This symposium brings together points of view, experiences and ideas on rock bursts from a goodly portion of the globe. Some conceptions, particularly those regarding the necessity of depth, have been fairly well shattered, as we find that they are present in the water tunnels of New York, on the surface at marble quarries in Vermont, and in the coal mines of the United States, as well as in the deep mines of the South African and Kolar gold fields, and in the nickel, copper and gold mines of Canada. Their occurrence under such a variety of conditions is, therefore, a challenge, which, if successfully met and overcome,

Jan 1, 1946

By Frederick Laist

I. EXPERIMENTAL FLOTATION CONCENTRATION INTRODUCTION EARLY in 1914 it was decided to test, on a fairly large scale, the treatment by flotation of Anaconda slime and mill tailing. For this purpose a standard-type Minerals. Separation machine was installed at the Washoe Reduction Works during May and June, 1914. This was followed by the. installation of a full-size Callow pneumatic machine plant. Experiments were also made, on a smaller scale, with the Froment, the Towne, the Fields, and the Anaconda flotation machines. The last-named machine was developed at this plant. In addition to the tests made in the standard-type Minerals Separation machine some tests were made using a Minerals Separation machine of the sub-aeration type. During the series of experiments a large variety of oils was tested. Experiments were also conducted using both round-table feed and tailing to determine whether it would be better to displace the round tables by flotation for the treatment of the slime, or to supplement the round tables by flotation of the round-table tailing. A series of tests was also made on the treatment of the mill tailing by grinding followed by flotation to determine the relative merits of flotation and leaching for the treatment of this product. In addition, flotation tests were made on mixtures of mill tailing and slime. The round-table feed referred to above is the total slime from the mill. It contains about 35 per cent. colloidal solids and approximately 90 to 95 per cent. of the total solids will pass through 200 mesh (0.067 mm.). It assays from 2.3 to 2.6 per cent. Cu. The mill tailing referred to above is the total discard from the mill, exclusive of the slime. It is all finer than 2 mm. and about 90 to 95 per cent. will remain on 0.25 mm. It assays about 0.60 per cent. Cu. A brief summary of the experimental flotation results follows:

Jan 3, 1916

By Albert E. Wiggin, Frederick Laist

Early ill 1914 it was decided to test, on a fairly large scale, the treatment by flotation of Anaconda slime and mill tailing. For this purpose a standard-type Minerals Separation machine was installed at the Washoe Reduction Works during May and June, 1914. This was followed by the installation of a full-size Callow pneumatic machine plant. Experiments were also made, on a smaller scale, with the Froment, the Towne, the Fields, and the Anaconda flotation machines. The last-named machine was developed at this plant. In addition to the tests made in the standard-type Minerals Separation machine some tests were made using a Minerals Separation machine of the sub-aeration type. During the series of experiments a large variety of oils was tested. Experiments were also conducted using both round-table feed and tailing to determine whether it would be better to displace the round tables by flotation for the treatment of the slime, or to supplement the round tables by flotation of the round-table tailing. A series of tests was also made on the treatment of the mill tailing by grinding followed by flotation to determine the relative merits of flotation and leaching for the treatment of this product. In addition, flotation tests were made on mixtures of mill tailing and slime. The round-table feed referred to above is the total slime from the mill. It contains about 35 per cent. colloidal solids and approximately 90 to 95 per cent. of the total solids will pass through 200 mesh (0.067 mm.). It assays from 2.3 to 2.6 per cent. Cu. The mill tailing referred to above is the total discard from the mill, exclusive of the slime. It is all finer than 2 mm. and about 90 to 95 per cent. will remain on 0.25 mm. It assays about 0.60 per cent. Cu. A brief summary of the experimental flotation results follows:

Jan 1, 1917

By W. M. Corse

AS THE outstanding contribution of the Committee on Correlation of Research of the Institute of Metals Division for 1932, may be mentioned the publication of Bureau of Mines Information Circular 6637, entitled "Research Activities in the Mineral Industries of the United States." This circular was compiled by A. C. Fieldner and Alden H. Emery, members of the Committee, in cooperation with the Bureau, and comprises a285-page list of research problems reported to the Bureau as engaging the attention of the various mineral industries. To obtain this information questionnaires were sent to 106 governmental agencies, 338 trade and professional associations, 524 colleges and universities, 9 endowed research institutions, and 1847 private companies and consulting laboratories. In order that the returns should be as complete as possible, the original mailing list included names from which it was not expected much pertinent information would be obtained. However, the procedure was justified as significant returns were obtained from many of these.

Jan 1, 1933

By Edward F. Divers

Face ventilation is generally the most critical area in the coal mine ventilation system. Various studies have repeatedly shown that good ventilation is by far the most effective and least costly method of controlling dust and gas problems created during face operations. The Bureau of Mines has recently developed and assisted in the development of several new concepts in face ventilation systems, and in methods to accurately evaluate these systems underground. A new type of scrubber and ventilation system design built into the auger support frame of a continu- ous miner was developed. The objective was to improve face ventilation and reduce respirable dust concentrations. With this arrangement, one scrubber is mounted into each side of the boom. Laboratory and underground tests of various scrubber discharge arrangements showed good to excellent dust and methane control. Combined face ventilation systems, using both blowing and exhaust curtain, potentially offer dust and gas control and deeper cutting. Bureau tests at a mine using a combined face ventilation system and remote- control-operated continuous miners showed excellent dust and methane control. The advancement of line curtain systems beyond permanent supports without exposing workmen to roof fall hazards can be accomplished only with specially designed extendable devices. Numerous concepts for line curtain extension have been developed and tested. For the past several years, the Bureau has been testing various types of extensible face ventilation systems. These extensible systems can generally be classified as floor-, roof-, machine-, and rib-mounted systems. In the past 6 years, approximately 40 systems have been evaluated for feasibility. From these, several have been selected as practical or innovative and are presented herein. A technique developed by the Bureau to accurately and safely evaluate the effectiveness of face ventilation is also presented.

Jan 1, 1982