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CONTENTS PAGE CARMICHAEL, NORMAN, and KIDDIE, JOHN.-Development of Mine Transportation in Clifton-Morenci District. Discussed by Norman Carmichael, Charles Legrand, B. B. Gottsberger 1 BARER, THOMAS C.-Fresnillo - Glory-hole Mining Practice. Discussed by Charles A. Mitke, B. B. Gottsberger, E. R. Thomas, Enoch Perkins..: 3 BRADLEY, P. R.-Estimation of Ore Reserves and Mining Methods in Alaska Juneau Mine. Discussed by R. M. Raymond, A. H. Rogers, Enoch Perkins, H. G. Moulton 6 BIRCH, STEPHEN.-Geology and Mining Methods of the Kennecott and Beatson Mines. Discussed by R. M. Raymond, Alan M. Bateman, Enoch Perkins 8 LEES, CHARLES E.-Mining Methods and Costs at the Iron Cap Copper Co., Copper Hill, Ariz. Discussed by A. L. Walker, A. Neustaedter 10 BELL, CHARLES N. -Mining Methods of the Telluride District. Discussed by Charles S. Hurter 10 Development of Mine Transportation in Clifton-Morenci District Discussion of the paper of NORMAN CARMICHAEL and JOHN KIDDIE, presented at the New York Meeting, February, 1924, and issued, as. Paper No. 1310-M, with MINING AND METALLURGY, March, 1924. NORMAN CARMICHAEL.-We realized the objections too the gable-bottom car, but were almost forced to its adoption by the same reasons that caused us to retain the 20-in. gage. To use another car would have meant a vast number of changes, for our transportation system was quite extensive; all mine chutes and ore bins were arranged for that car. Had we been laying out, new works, many of our decisions would have been different. MEMBER.-If you were planning it now, would you not put in box bottom cars with a rotary dump? NORMAN CARMICHAEL.-We surely would. One objection to the gable-bottom car is the spill. No, matter how carefully the cars are kept up,: there is always leakage and spill. The cost of keeping and maintaining the cars in a good state of repair, so as to keep that loss at a minimum, is not necessary for a box-bottom car.

Jan 6, 1924

CONTENTS PAGE Ross, J. M. and WAYLAND, R. G.-Mining Methods at the Homestake. Discussed by Benjamin F. Tillson, R. M. Raymond, I, H. Barkdoll, Arthur Notman 1 EMMEL, RUDOLPH.-Mining Methods in Zaruma District, Ecuador. Discussed by Rudolph Emmel, George A. Packard, Fred Hellmann, R. M. Raymond, Arthur Notman 2 MISHLER, R. T. and BUDROW, L. R.-Methods of Mining and Ore Estimation at Lucky Tiger Mine. Discussed by Fred Hellmann, Benjamin F. Tillson...4 PARK, JOHN FURNESS.-Mining Methods of Jarbidge District. . Discussed by R. S. Lewis : 5 Mining Methods at the Homestake Discussion of the paper of A. J. M. Ross and R. G. WAYLAND, presented at the New York Meeting, February, 1925, and issued, as Paper No. 1408-A, with MINING AND METALLURGY, February, 1925. BENJAMIN F. TILLSON, * Franklin, N. J.--It requires a good deal of timber to operate, especially the caving systems. An important function in mine operations now seems to be forestry and to operate a timber tract in order to insure a supply of timber. By depleting the timber resources of your section, you only increase your costs later when timber must be brought in from the Pacific Coast or the East. Our experience has been that any square-set method of timbering is the most expensive. Timbering for stoping systems, top slicing if you will, although it uses a large volume of time does not require as expensive timbering as the square-set method; also it does not require as long a life for-the timber, so that such wood as birch and maple, which have strength but not long life under the fungus conditions in the mine, may be used. All the drifts in the orebody are thoroughly timbered, and it has required a lot of timber. If we had it to do over, we would spend a lot more money in the development of rock drifts; as a matter of fact, we must ultimately come to that any way.

Jan 6, 1925

CONTENTS PAGE FULTON, CHARLES H., and READ, J. BURNS-A New Roasting Furnace for Zinc Flotation Concentrate. Discussed by Charles H. Fulton, Arthur S. Dwight, B. M. O'Harra, Kurt Stock 1 STOCK, KURT.-Redistillation of Zinc. Discussed by G. E. Dalbey, Kurt Stock.. 3 BEASLEY, F. E.-High Zinc in Lead Blast-furnace Slags. Discussed by R. C. Canby, R. L. Lloyd, C. R. Haywood, G. E. Dalbey, A. S. Dwight, E. P. Mathewson, A. L. Walker, B. M. O'Harra, and C. P. Linville 4 STEELE, E. W.-Application of Pulverized Coal to Copper Refinery Furnaces. Discussed by F. R. Pyne, E. P. Mathewson 11 LINVILLE, C. P.-Recovery of Arsenic and Other Valuable Constituents from Speiss. Discussed by C. R. Hayward, C. P. Linville, G. E. Dalbey, A. S. Dwight, Edward F. Kern, Karl Eilers, E. P. Mathewson 12 A New Roasting Furnace for Zinc Flotation Concentrate Discussion of the paper of CHARLES H. FULTON and J. BURNS READ, presented at the New York Meeting, February, 1925, and issued, as Paper No. 1362-D, with MINING AND METALLURGY,. October, 1924. G. E. DALBEY, East Berlin, Conn. What would be the, effect on the formation of sulfates of an increased water vapor content in the roasting gases? CHARLES H. FULTON.-I cannot answer that from our experience. The question of the formation of sulfate in the roasting of zinc is mainly one of temperature and the concentration of S02 and S03 in the gases. We found we could roast almost completely to sulfate if the concentration was kept at the proper point. We, however, did not care to do this because we wished to make a 5 to 6 per cent. S02 gas for sulfuric-acid work. The sulfating of the zinc oxide in the proper concentration of gases goes on very rapidly. There are certain places in the furnace system such as the Cottrell and in a part of the dust chamber in which the roasted

Jan 6, 1925

CONTENTS PAGE THOENEN, J. R.-Limestone Production as a Mining Problem. Discussed by Oliver Bowles, J. T. Singewald, S. R. Russell 1 GRIGGS, C. C.-Engineering in Limestone Production. Discussed by W. C. Phalen, John Rice, Samuel M. Shallcross, Oliver Bowles, Nathan C. Rockwood, George Milliron 2 WILDER, FRANK A.-Rotary Calciners for Gypsum. Discussed by L. K. Arm-strong 9 PORTER, JOHN J.-Manufacturing Problems of Cement Industry. Discussed by Samuel M. Shallcross 9 KIRKHAM, VIRGIL R. D.-Phosphate Deposits of Idaho and Their Relation to the World Supply. Discussed by F. A. Wilder, S. L. Willis, G. R. Mansfield, R. W. Stone, L. K. Armstrong 9 Limestone Production as a Mining Problem Discussion of the paper of J. R. THOENEN, presented at the New York Meeting, February, 1925, and issued, as Paper 1417-H, with MINING AND METALLURGY, February, 1925. OLIVER BOWLES, New Brunswick, N. J.-I am so thoroughly convinced of the growing importance of underground work in the production of limestone that I had the author make a detailed study of limestone mining for the Bureau of Mines and prepare a report on the principles of limestone mining. Many limestone operators, long accustomed to open¬pit work, are being forced to mining. About 6 months ago I thought there were twenty-five or thirty underground limestone operations in the United States but the author has been finding new ones until his list now runs nearer sixty. Some of these are very extensive; one at least has 4 ½ miles of underground workings. There is an ever-expanding field for the engineer in the operation of limestone mines and quarries. Some of the larger companies realize the need of skilled engineering advice, but many of the companies regard the engineer as an unnecessary expense. Although almost every metal mine, even those handling only a few hundred tons of ore per month, employs a mining engineer, many limestone operations ten times as large employ no mining engineers. Few mining engineers are at all familiar

Jan 6, 1925

PRESIDENT WHITESIDE: The chair will now throw the meeting open to discussion. GEO. B. PRYDE: In the old days at Rock Springs we had electric plants situated about half a mile from our mines; we had small boiler plants; we had an electric plant with about 600 kilowatt capacity. About ten years ago we discarded the old steam plants and started building towards a centralized power plant. We now have three 2,500-kilowatt turbine generators and one 1,000, and our peak load is about 7,000 kilowatts. We have had to rebuild the old power plant, scrap the old machines, and install water tube boilers. We did this as a matter of economy in a small local plant we had years ago, and it has grown to be a large central plant, supplying power for about 20,000 tons of coal daily, and distributing this power within a radius of twenty miles. We have found this method of power to be more economical than with the old plants, and the people who buy power from us in the Rock Springs field say it has been to their advantage also. We found this last year, when we had to shut down for five months, that that plant was the only plant operating in the Rock Springs field, supplying all the power, running of fans and pumping during the time the mines were shut down, and it helped the situation very much. We had an old wooden building which we had to tear down, raise the walls, and put on a steel roof; had to rebuild the boiler room and rebuild the boilers. The water situation at Rock Springs has never been very good; we get our water from wells 250 to 500 feet deep, and use one and one-quarter million gallons a week. We have two large spray ponds and we have gotten along well. There isn't any comparison between the central power station and the old method of making power. (Applause.) FRANK YOUNG: I listened with a great deal of pleasure to the paper just read, and it struck me it was remarkable how a paper prepared by anyone could be so nearly identical and coincide so very near with the experience of another. It is just like some work I have had. I had the engineering part to do for the power plant for ten years, and I think at that time we did all of the things that he mentioned in his paper. Also his analysis of the cost of power seems to me exactly right. If I had gathered the figures and made the statement myself I think it would have been very much the same as was read. The recommendation that it is better to buy

Jan 1, 1923

H. C. GLAZE: There is no question in my mind that the day of direct current distribution is practically ended so far as large coal properties are concerned. Another thing that Mr. Drennan touched on that is of the utmost importance, is that of voltage-voltage to the various pieces of equipment inside the mine. You all know how expensive it is to have motors in operation in important places where the voltage .is about half that which the motor should have. This is particularly true in the direct current system. It slows down production, causes burnouts and destruction to apparatus, and is a question that you men have got to go into. It costs a great deal of money, as Mr. Drennan pointed out, to take care of this. The wires are large and cumbersome, while; on the other hand, with an alternating current system you can use a minimum amount of wire. We have installed this class of equipment with so-called "pick-proof" cable of 2,200 volts down slopes, and I have never heard of any trouble whatsoever from this cause.

Jan 1, 1923

By D. C. McClure

MR. McCLURE: Mr. Chairman, you sprang a surprise on me; I really came over here for a good time. Gentlemen, I am not at all qualified to pose as an expert on pulverized fuel; I have merely been making some rather interesting observations, and unfortunately at the present time, a great deal of substantial data, the technical data, I don't happen to have with me; it is still in the process of being calculated, but I will be very glad to tell you some of the observations as I have made them, and in as truthful and complete a way as I can. The question of how we would handle fuel became a very pressing subject in this new Valmont electric plant, which is now under progress. We have studied the methods of burning fuel for a number of years on different types of stokers at the existing plants in Denver; we are burning it with a natural draft chain grate and with underfeed and with forced draft chain grates, and I am very frank to confess at the present time that I have no answer as far as stokers are concerned for a better solution of the problem of burning lignite. In other words, I could not tell you that this or that is a better type of stoker to use for that coal. However, to boil the thing down, after considerable trials, the underfed stoker was chosen as the one most adaptable for the utilizing of lignite fuel if stokers are to be used. In other words, the chain grate was put aside. I might say in support of the chain grate, the prime reason for which that type of stoker was condemned, as far as lignite goes, is the initial investment charge and the large maintenance which is involved.

Jan 1, 1923

CONTENTS PAGE BARTON, D. C.-The Eötvös Torsion Balance Method of mapping Geologic Structure (T. P. No. 50) 1 GEORGE, P. W.-Experiments with Eötvös Torsion Balance in the Tri-State Zinc and Lead District (T. P. No. 65). 15 LANCASTER-JONES, E.-The Computation of Eötvös Gravity Effects (T. P. No.75) HEILAND, C. A.-A Cartographic Correction for the Eötvös Torsion Balance-(T. P. No. 52) 17 SLICHTER; L. B.-Certain Aspects of Magnetic Surveying (T. P. No. 120). . . . 18 WEAVER, W.-Certain Applications of the Surface Potential Method (T. P. No.121) LUNDBERG, H.-Recent Results in Electrical Prospecting for Ore (T. P. No. 98). . 20 HOTCHKISS, W. 0., ROONEY, W. J. and FISHER, J.-Earth-resistivity Measure-ments in the Lake Superior Copper Country (T. P. No. 82) 21 LEONARDON, E. G. and KELLY, S. F.-Some Applications of Potential Methods to Structural Studies (T. P. No. 115) 23 MASON, M.-Geophysical Exploration for Ores (T. P. No. 45) 25 The Eötvös. Torsion Balance Method of Mapping Geologic Structure Discussion of the paper of D. C.. Barton, issued as Technical Publication No. 50 with Mining and, Metallurgy, February, 1928. D. C. BARTON.-The field surveys which I have been privileged to use as illustrations for this paper were done for Mr. DeGolyer's companies and were released through his favor. W. J. MILLARD, Tulsa, Okla.-Has any oil been found by the torsion balance in West Texas? D. C. BARTON.-NO new oilfield has been discovered on the basis of torsion balance work. It has had some part in controlling the policy of certain companies in playing the extension of known oil fields. A number of "T. B." structures have been drilled and dry holes obtained. Of those known to the writer, one apparently was a structural high, one is a broad general high but locally low and probably is a deep-seated structural high, one seems normal although the control is poor, and one was considered structurally low but is now suspected by some geologists of being structurally high. E. L. DEGOLYER, New York, N. Y.-A large gravity structure, generally referred to, I believe, as the Crosby County Structure, has been found in West Texas. This structure is perfectly symmetrical with the arrows all pointing toward a common center, very much like the Nash salt-dome pattern in Dr. Barton's paper (Fig. 9). One of the peculiar things about it, from the standpoint of the gravity high, is that it is so

Jan 1, 1928

CONTENTS CATES, LOUIS S.-Factors Affecting Bank Slopes in Steam-shovel Operations. Discussed by Fred Hellman, Louis S. Cates, W. D. B. Motter, Jr., George S. Rice 1 CRANE, W. R.-Mine Subsidence in the Red Iron Ore Mines of the Birmingham District, Alabama. Discussed by George S. Rice, W. R. Crane, Louis S. Cates : 3 Factors Affecting Bank Slopes in Steam-shovel Operations Discussion of the paper of Louis S. CATES, presented at the New York Meeting, February, 1925, and issued, as Paper No. 1360-M, with MINING AND METAL-LURGY, August, 1924. FRED HELLMAN, New York.-My experience with shovel mining has been restricted almost entirely to Chuquicamata as far as operation is concerned. We had there an unusual condition in that the rock is cohesive because of the salts in it, so that you can probably work higher banks than is possible in most places. Recently they have reduced the height of the banks and have found that lower bank affords better working condition than the higher bank. It took two years of experimentation to determine the best height of bank for that particular mine. Each mine should be considered by itself and, to state off hand the best height of bank. for any given mine is impossible. We worked the high banks in Chile without much trouble. We adopted high banks in the beginning in order to obtain the minimum expense in railway approaches at that time. The first plan was for 50 ft.; then to get production started with the smallest possible expenditure of money, the approach to the deposit was changed and the first bank had an ultimate height of about 180 ft. We worked that bank; quite success-fully, but I do not think that it could be done anywhere else.

Jan 7, 1925

Endurance Properties of Non-ferrous Metals Discussion of the paper of D. J. McADAM, JR., presented at the Syracuse Meeting of the Institute of Metals Division and issued, as Paper No. 1506-E, with Mining AND METALLURGY, October, 1925. H. F. MOORE,* Urbana, Ill. (written discussion).-This paper says that the results of tests of some non-ferrous metals made at the University of Illinois and in the testing laboratories at McCook Field are abnormal when they do not agree with results obtained by the author. The writer can see no inherent reason why results of the type uniformly reported in this paper are any more normal. The knee of the stress-cycle, or S-N, diagram comes at different lengths of life for different metals. For steel, the knee occurs after from 1,000,000 to about 4,000,000 cycles, and for some non-ferrous metals not before 20,000,000 of 30,000,000 cycles. The writer can see nothing inherently abnormal in finding certain nonferrous metals for which the knee of the stress-cycle curve occurs at 1,000,000,000 cycles or higher. The writer has had experience with both the cantilever and the rotating-beam testing machine, and thinks that the chance of whipping action in the cantilever machine is a more serious handicap than the action the author has pictured. Furthermore, the writer questions whether the author has shown the existence of a clearly marked and definite endurance limit for all the non-ferrous metals he has tested including the following: Nickel (CT and A-16, Fig. 1), monel (CS-5.5 and BK, Fig. 2), bronze (F and CK, Fig. 4), aluminum bronze ( BJb-1, Fig. 6).

Jan 12, 1925

CONTENTS PAGE PEIRCE, CARL-Making Rimmed Steel. Discussed by L. F. Reinartz. H. D. Hibbard, C. L. Kinney, Jr., A. H. Woodward, V. B. Buck, A. L. Feild, J. V. W. Reynders 1 SCHROEDER, F. W., and LARSEN, B. M.-Progress Report of the Effect of the Open-hearth Process on Refractories. Discussed by D. A. Lyon 12 KEATS, J. L., and HERTY, C. H.-Elimination of Metalloids in the Basic Open-hearth Process. Discussed by J. V. W. Reynders 14 Making Rimmed Steel Discussion of paper by CARL PEIRCE, presented at the New York fleeting and issued, as Paper No. 1563-C, with MINING AND METALLURGY, March, 1926. L. F. REINARTZ, Middletown, Ohio.-Mr. Carl Peirce has presented a valuable paper on a subject that has been very widely discussed in recent years, especially since the demand for high finish, deep drawing and other grades of sheet steel in the lower carbon ranges has become an important factor in the steel business. Steel of this analysis has been produced for many years, but the product for which it was made did not require the extra care in the steel plant that it does today. It must now be worked down into thin sheets for special purposes and undergo many severe finishing processes both in the steel mill and in the fabricating plants. Mr. Peirce's paper has outlined in a concise and logical manner the steps which must be taken in manufacturing such steels. The secret of successs is attention to details of well known steel practices. I agree with him that quality steels of this class cannot normally be made out of inferior raw materials. Scrap should be clean and if possible not too variable in analysis. Galvanized scrap or babbit are particularly objectionable. Scrap should be in such physical condition that undue delays are not encountered in charging the furnace. Limestone should preferably contain over 95 per cent. available calcium carbonate, and be free from clay or other foreign substances. Almost universal practice shows that 10 per cent. limestone is required for proper slag volumes to protect the metal from over oxidation. The use of 8 per cent. limestone makes the operation less fool-proof.

Jan 4, 1926

CONTENTS PAGE ANDERSON, ARVID E., and CAMERON, FRANK K.-Recovery of Copper by Leaching, Ohio Copper Co. of Utah. Discussed by Thomas B. Brighton, H. C. Goodrich, Arvid E. Anderson, Thos. P. Billings, Frank K. Cameron 2 BEESON, J. J.-Mining Districts and Their Relation to Structural Geology. Discussed by Charles Keyes, Chas. A. Porter 4 DOBBEL, CHAS. A.-Deep-hole Prospecting at the Chief Consolidated Mines. Discussed by G. W. Crane 10 CRANE, G. W.-Notes on the Geology of East Tintic. Discussed by G. W. Crane, H. E. Havernor, N. O. Lawton 11 SACKETT, B. L., BARDWELL, CARLOS, JACOBSON, SIMON, and JENSEN, N. H. Lead Smelting in Utah. Discussed by D. W. Jessup, B. L. Sackett, E. H. Laws 13 BARDWELL, E. S., and MILLER, Roy H.-Pulverized Coal as Fuel for Copper Refining Furnaces. Discussed by L. D. Anderson, E. S. Bardwell, C. P. Crawford 15 WIGTON, G. H.-The Chief Consolidated Volatilization Process and Mill. Discussed by Thomas Varley, S. G. Olmstead, V. O. Lawton, O. C. Ralston.... 16 JESSUP, D. W.-Evolution in the Preparation of Ores for Lead Blast Furnaces. Discussed by W. Spencer Reid, D. W. Jessup, Carlos Bardwell 19 ALLEN, H. P., and MADGE, WM. C.-Chloridizing Mill of the Standard Reduction Co. Discussed by Thomas Varley, H. R. Hanley, H. P. Allen, George H. Dern 20 TUCKER, E. L., and HEAD, R. E.-Effect of Cyanogen Compounds on Floatability of Pure Sulfide Minerals. Discussed by Blarney Stevens 24 Mix, B. E., and BARKER, L. M.-Method of Unloading Ores and Coarse-crushing Practice at Magna Plant of Utah Copper Co. Discussed by W. C. Madge,B. E. Mix 25 KEIGLEY, C. T.-The New Byproduct Coke Plant of the Columbia Steel Corporation. Discussed by W. M. Grant, C. T. Keigley, A. C. Feilder 25 JACKSON, P. W.-Blast Furnace Plant of the Columbia Steel Corporation. Discussed by W. R. Phibbs, H. M. Henton 26 OLDRIGHT, G. L., KEYES, H. E., and WARTMAN, F. S.-Production of Ferric Sulfate and Sulfuric Acid from Roaster Gas. Discussed by G. D. Van Arsdale William E. Greenawalt, G. L. Oldright 27 MAZANY, M. S.-Braden Copper Company Caletones Smelter. Discussed by A. B. Young, G. L. Oldright 36 HARRINGTON, D.-Safety Methods in Utah Coal Mines. Discussed by Edward K. Judd, Otto Herres, Benedict Shubart, A. C. Watts, D. Harrington 36

Jan 12, 1925

CONTENTS PAGE FOGLER, M. F., and QUINN, E. J.-Scratch and Brinell Hardness of Severely Cold-rolled Metals. Discussed by H. S. Rawdon, Carl Benedicks, M. F. Fogler, A. L.Davis 1 GREEN, C. H. Eutectic Patterns in Metallic Alloys. Discussed by Carl Benedicks, Carle R. Hayward, G. E. Dalbey, George F. Comstock, C. H. Green. 3 ARCHER, ROBERT S., and JEFFRIES, ZAY.-New Developments in High-strength Aluminum Alloys. - Discussed by F. B. Coyle, M. F. Fogler, Zay. Jeffries, D. J. McAdam, Jr., Horace C. Knerr, Ernest Schweizer 6 FLICK, FULTON B.-Etching Aluminum and Its Alloys for Macroscopic and Microscopic Examination. Discussed by Samuel Daniels 22. MERICA, PAUL D., and WALTENBERG, R. G.-The Malleability of Nickel. Discussed by H. W. Gillett, Ancel St. John. L. W. McKeehan, A. L. Feild, A. L. Davis 23 ANDERSON, ROBERT J., and NORTON, JOHN T.-X-ray Evidence Versus the Amorphous-metal Hypothesis. Discussed by Zay Jeffries, Chu Phay Yap, Francis B. Foley, H. H. Lester, Edgar C. Bain, Ancel St. John, L. W. McKeehan, Carle R. Hayward, R. P: Heuer, Jerome Alexander, Carl Benedicks 26 COOK, MAURICE, and EVANS, ULICK R.-Recrystallization and Grain Growth in Soft Metals. Discussed by M. F. Fogler 36 POLUSHKIN, E. P.-Determination of Structural Composition of Alloys by a . Metallographic Planimeter. Discussed by H. S. Rawdon 36 BASSETT, WILLIAM H., and DAVIS, C. H.-Corrosion of Copper Alloys in Sea Water. Discussed by W. B. Price, W.. R. Webster, George A. Orrok, A. E. White, William H. Bassett, D. K. Crampton 38, Scratch and Brinell Hardness of Severely Cold-rolled Metals Discussion of the paper of M. F. FOGLER and E. J. QUINN, presented at the New York Meeting, February, 1925, and issued as Paper No. 1395-E with MINING AND METALLURGY, January, 1925. H. S. RAWDON, * Washington, D. C.-We had the privilege of looking over the data just given before they were published and we were not able to suggest any convincing reason for the differences that were secured

Jan 6, 1925

CONTENTS PAGE UREN, LESTER C.-Increasing Production of Petroleum by Increasing Diameter of Wells. Discussed by A. Beeby Thompson 1 LAHEE, FREDERIC H.-Comparative Study of Well Logs on the Mexia Type of Structure. Discussed by W. A. I. M. van Waterschoot van -der Gracht.... 4 Increasing Production of Petroleum by Increasing Diameter of Wells Discussion of the paper of LESTER C. UREN, presented at the New York Meeting, February, 1925, and issued, as Paper No. 1364-G, with MINING AND METAL-LURGY, October, 1924. A. BEEBY THOMPSON, London, Eng. (written discussion).-The subject discussed in this paper has long been debated by operators in European fields, where very strong views are held regarding the advisability of controlling gas pressures by shutting in wells. While unwilling to theorize on the subject of restricted flow, the writer has always been disposed to associate himself with those who hesitate to impose any obstruction to a natural transitory state that breaks up the oil-containing strata and establishes a feeder system which no subsequent events, natural or artificial, can approach in intensity. In both Russia and Roumania, where the oil is concentrated in discontinuous, disturbed, and irregular lenticles of sand varying, within short distances, in coarseness of grain, extent of impregnation and degree of cementation, it has been the practice to let the wells run wild in order to provoke disruption of strata. By encouraging violent eruptions, an extended feeder system is created and the ejection of enormous quantities of sand, rock, and clay creates a sump and seepage area that it would be difficult to imitate by any artificial means, not excluding actual mining. Before discussing the somewhat novel method suggested for enlarging the infiltration area, the writer would like to confirm the fact that many valuable data applicable to oil are forthcoming from a study of water phenomena. Long association with water-supply problems in many parts of the world has shown how closely the phenomena of underground movements of water and oil are related, so that it is pleasing to note the author's use of water formulas. But there is one great distinction;

Jan 7, 1925

Discussion of the previous paper E. N. H. MOLLOY The first 22-foot-diameter Aerofall mill was installed at Mangula in 1957. This was fitted with cast-iron trunnion'! located to the mill shell with 2-inch-diameter mild-steel bolts. O.F .S. Branch Minutes of the General Meeting held at the Welkom Club on Wednesday, 2nd June, 1976, at 4.00 p.m. Mr G. J. C. Young (Chairman of the O.F.S. Branch) was in the Chair. Also present were:

Jan 9, 1976

By M. G. Spengler

Mr More O'Ferrall must be complimented on a paper that will be a useful reference for the re-working of previously abandoned workings. His paper so closely mirrors experiences at East Rand Proprietary Mines, Limited, that it could well have been based on occurrences in that mine. Corrosion The Scientific Society of Mechanical Engineers is organizing the 115th event of the European Federation for Corrosion in Budapest, from 18th to 22nd October 1982.

Jan 1, 1981

This paper will be a discussion of the geological exploration and drilling carried out on the Mt Davy Block, Greymouth Coalfield. A brief summary of the geology of the Greymouth Coalfield will be given to put the Mt Davy Block into perspective.

Jan 1, 1979

By A. C. Callen

This, report represents the comments of the individual members of the A. I. M. E. Sub-committee on Physics of Mine Ventilation on the proposals of a special committee of the Institution of Mining Engineers (London). As might be expected, there is a certain diversity of opinions, for owing to the shortness of time- it was not possible for the sub-committee to get together for informal discussion. The report is presented in this form in the hope that it will bring out a full discussion by other members in the Institute. OLE SINGSTAD?, New York, N. Y.-The Atkinson formula, P =SV2 K a is quoted and it is stated that this formula is especially applicable to mine galleries but is unwieldy in application, as in many problems the value of K, S and a are assumed not to change. This is the same formula that was used during the preliminary calculations for the ventilation of the Holland Tunnel, and where the above-mentioned values were constant for a number of cases, it was a very simple matter to rewrite the equation n the form P = K1V2 and avoid the repeated use of identical figures. The Atkinson formula assumes 1. That resistance to flow is independent of the pressure. 2. Changes in volume due to change in pressure may be neglected. 3. Changes in density and viscosity may be neglected. 4. That the coefficient K is a constant. 5. That P is proportional to V2. We found, from our experiments in connection with the ventilation of the Holland Tunnel, that all the above assumptions could be safely made, with the exception of No. 3, and No. 4 at, very low velocities. In mine work, where many assumptions must necessarily be made, it would seem inconsistent to attempt to make any allowance for the other factors, which are so small that they can be determined only by the most careful experimental work. However, P does depend directly on the density of the air, and to that extent the Atkinson formula is incomplete.

Jan 2, 1926

PRESIDENT PRYDE: Any discussion on Mr. Poster's paper? MR. J. BEVAN: I would like to ask the gentleman how fine the dust has to be to cause an explosion? MR. T. FOSTER: According to the Bureau of Mines, it is claimed coal passing through a 100 mesh screen would be considered fine enough. That is all I can learn from the different bulletins. MR. BEVAN: Will the coal dust be that fine; going back in the empty cars on the tipple in the mine? MR. FOSTER: Possibly a great deal of it would be. MR. BEVAN: Will the coal dust be that fine, going back, in the empty the coal dust going back in the cars on the tipple, and into the mine? MR. FOSTER: In some places, they are wetting the cars at the tipple, -in the Rock Springs District, we have as the trip goes out, they have a big pipe, and they souse the car, and wet the load, and in some places, near the timbers; that helps to a certain extent. That does not absolutely eliminate it all, but it helps considerable. MR. WM. LITTLEJOHN (Utah Fuel Company) : I think we have all listened very attentively to the paper that Mr. Foster has just read. He has brought up a subject rather close to my heart, for a long time. He mentions particularly, the Scofield disaster, which happened the first of May, 1900; two hundred men lost their lives in the explosion; and I think it is generally conceded that is about the first time it had ever been brought to the attention of coal miners or operators that such a thing was possible, namely, a purely coal dust explosion. The term "Scofield disaster" is rather a mistake, in a way; while the mine that exploded at the time is in the Scofield District all right, it is now known, and probably was known at that time, as the Winter Quarters Mine, one of the mines which belongs to the Utah Fuel Company at the present time, and did at that time. This mine

Jan 1, 1924

A-Metal Mining B-Minerals Beneficiation F-Coal H-Industrial Minerals

Jan 11, 1950