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By Chester Wells Purington

Situation.—The Camp Bird mine is in Imogene basin† (Fig. 1) at the head-waters of Canon creek, a branch of the Gunnison, in the southern part of Ouray county, Colorado, towards the northern edge of the region known as the San Juan mountains, and about 10 miles W. of the continental divide. It is 8 miles by wagon-road from Ouray, the terminus of a branch of the Rio Grande' Southern railway. The distance from Denver to Ouray is 387 miles by rail. In an air-line, the mine is 190 miles SW. of Denver. The altitude of the town, tunnel and buildings is 11,200 ft., and level No. 2 is 11,500 ft., and No. 1 is 11,670 ft., above sea-level. The lowest point of the lode-ontcrop, which crosses the basin E. and W., has an elevation of 11,850 ft., and that of the highest point, on the divide between Imogene and Tomboy basins, is 13,250 ft. On the eastern slope of the Imogene basin (towards Ironton) the vein is less clearly defined on the surface. Ownership and Extent.—At the time of the writing of this paper, the property is owned by Mr. Thomas I?. Walsh, and operated under the management of Mr. J. W. Benson. It

Jan 1, 1903

By Harold R. Larson, John F. Elliott

The standard free energies of formation of several nzetallic sulfides have been measured by a reversible electromotive-force cell employing stabilized zir-conia as the electrolyte. The oxygen potential at the cathode was fixed by the use of pure oxygen gas at 1 atm. It was established at the anode by bringing to equilibrium the reaction between the sulfide and oxide species present. Thus, Gf: for the sulfide could be obtained from the cell potential and the standard free energies of formation of the oxides participating in the reaction. The results in calories per cam rnole for the temperature range 850" to 1100°C are: Use of the reversible electromotive-force cell having an oxide-ion electrolyte to obtain the standard free energies of formation of some of the more stable metallic sulfides offers a convenient experimental method that is very productive. It also avoids some of the problems inherent in the experimental methods' for such studies which rely on precise determination of gas compositions, particularly if these compositions lie near the limits of our capabilities for accurate chemical analyses. The reaction equilibrium between the lowest sulfide of a metal, SO2 at a fixed pressure, and an oxide of the metal has a characteristic oxygen potential. For example: and for metals whose lowest sulfide is much more stable than the oxides of the metal, the equivalent reaction might be:

Jan 1, 1968

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

The Colorado School of Mines, Golden, Colo. M F Coolbaugh, President. Since 1906 the School of Mines has issued a journal, known as the Quarterly of the Colorado School of Mines, which carries many articles on matters of general interest as well as other articles of a technical nature There is no regular subscription price to the School of Mines publications Anyone interested in back numbers should write and find out the conditions under which individual copies may be obtained, whether a price is set on them or whether they are free Some back numbers are not now available but efforts will be made to supply copies from the files of alumni or other friends of the School Vol 23, No. 3 of the Quarterly (July, 1928) is an index of the publications complete from July, 1906 to July, 1928. A selected list of the technical articles appearing in the Quarterly is given here: Vol 3, No. 3, Rare metals. uranium and vanadium, by H. Fleck (1909), vol 3, No 4, Tungsten in Colorado, by H R Van Wagenen, vol 4, No 3, Preliminary report of the radioactivity of the carnotite of southwest Colorado, by H Fleck and W. G Haldane (1909), vol. 8, No 1 (1913), Some recent developments at Leadville, by G. M Butler, vol 8, No. 3, Physiography of

Jan 1, 1933

By Kenneth Cottingham

THE area described herein is situated on what is known as the Arches Fork anticline in Roane and Calhoun Counties, W. Va. When the area was first mapped, it was felt that well records would give a more intimate idea of conditions, both structural and lithologic, than could be expected from surface horizons. The surface formations are chiefly members of the Monongahela series, though northward the hilltop outcrops are those of the Dunkard. Neither series offers a key horizon sufficiently definite to be satisfactory, although the structure as determined from well records was later checked against two of the more persistent surface sandstones. In mapping the subsurface structure, the top of the Big Lime (Greenbrier) was employed as the key horizon. The average depth to the top of the Big Lime varies from 1600 to 2000 ft. (487 to 609 m.), while the average thickness as indicated by well records is 113 ft. (34 m.). The oil-producing formation is the Big Injun, lying just below the Big Lime. In two instances, well records show the Lime and Injun separated by a few feet of "break." The Big Injun is recorded as having a variable thickness. Seven logs report it as missing and one gives it the maximum thickness of 105 ft. (32 m.), while the entire average for thickness is 19 ft. (6 m.).

Jan 1, 1922

By Geo. W. Goetz

The following tables show the analyses of ores from nearly all of the mines which will produce over 10,000 tons of ore each during the season of 1890. There are many small mines now in the course of development, some of which may become large producers. Many of the mines produce several different grades of ore, but the analyses given in the tables are fair averages of ore such as the respective mines can deliver. Most of these analyses were obtained from the agents of the respective ores, and are averages of the season of 1889. One can state positively that over 75 per cent. of all the iron-ores of the Lake Superior district will average over 60 per cent. of metallic iron. During the past 34 years this region has produced about 48,137,421 tons of ore, the different districts contributing about as follows: Marquette District,. 29,754,057 Menominee " .10,415,859 Gogebic " . 6,622,194 Vermilion " . 2,342,991 Miscellaneous,. .. .. 2,320 In the year 1889, the product of all the districts was nearly '1,300,000 tons. The product of the entire region for the season of 1890 may exceed 9,000,000 tons. This large amount of ore is shipped to the lower lake ports, from Escanaba, Marquette, Two Harbors and Gladstone.

Jan 1, 1891

E.T. CONNER;. Scranton;. Pa-I had the honor of being associated with Mid. Griffith in an investigation of the Scranton mine cave problem several years ago; in the course of which we investigated rather carefully the bearing strength of various materials that might be utilized for, the support of over We found that there were no reliable data as to the resisting strength, for instance, of gob pillars or timber cogs or cribs, nor as to the amount of compression that might be expected under a given burden. We made a series of tests at the Fritz engineering laboratory of Lehigh University, from which we, reduced certain conclusions, subject, however, to further test before they could be definitely recommended. Onr study of the subject was later checked by a commission appointed by the Governor of the State of Pennsylvania, to investigate the same subject the subsidence of the surface, and the danger entailed thereby. The State, commission made a series of tests on a much more ambitious scale at Pittsburgh, in the laboratory of the U. S. Bureau of Mines, and their tests agreed quite closely with those that Mr. Griffith and I had made. As the result of our study, we determined that the most elastic support is the ordinary timber cog or crib, while the most rigid support is a

Jan 1, 1918

The conservation movement, initiated during the time of Gifford Pinchot and Theodore Roosevelt, has gradually taken hold of the popular imagination of the American people; and today, although it is little understood, it is an accepted doctrine. But the subject should not degenerate into cheap and misleading publicity. In the wise development and use of human and material resources lies the answer (Fig. 4). Conservation does not mean the parsimonious and misguided avarice of the miser, but the prudent and intelligent use of all types of resources, and the opening of a way for the use of those potentialities that lie just beyond the horizon and wait for man's constructive efforts to make them available. Conservation consists essentially in not emptying the pools of primary wealth before the minds of men, guided by ingenious research, have found ways to replenish them from sources as yet untapped. To advance successfully along this path, man should be guided by science and by a decent understanding of his obligations to his fellow man and particularly to his children and his children's children. Two pathways branch from this general road. One is the restraining of those spendthrifts who would throw away our national heritage for the sake of a cheap and irresponsible enjoyment of the present. Conservation in the generally understood sense usually has meant

Jan 1, 1950

The regular meeting of the Trustees of United Engineering Society was called to order at 4 P. M. Thursday, Feb. 27, 1919, in the Board Room of the American Society of Civil Engineers, Engineering Societies' Building, New York. Minutes of a joint meeting of the Finance Committee of United Engineering Society with finance committees of Founder Societies on Feb. 14, were presented. The President called attention to actions relating to the recataloging of the Library and the support of Engineering Societies Employment Bureau of Engineering Council. The activity of the Employment Bureau was approved and support by the Societies informally assured. In response to a communication from the Fifth Avenue Association, the Secretary was instructed to write favoring the continuance of the daylight saving law. As to recataloging of Engineering Societies Library, it was announced that the Mining, Mechanical, and Electrical Engineers had voted appropriations, as requested, and the action of the Civil Engineers was awaited. A list of applications for offices in Engineering Societies' Building, revised to Feb. 27, was read, showing requests for a total of 29 rooms. The President stated that a decision must be reached soon as to what reply shall he made to these applications. Charles F. Scott, one of the original trustees, who was present, remarked upon the growth of United Engineering Society and his satisfaction at its success. ALFRED D. FLINN, Secretary.

Jan 4, 1919

By W. F. Baldwin

The timing circuit generally employed in Carter Reservoir Behavior Analyzers consists of a synchronous motor driven cam which actuates a microswitch. A mechanically actuated timer of this type has several inherent disadvantages, among which are the following: 1. The first time interval may not be of uniform length, depending on the exact position of the cam at the conclusion of a previous run. 2. The positioning adjustments on the microswitch lever arms are critical and require periodic readjustment. 3. The mechanical system is subject to wear which will ultimately impair its accuracy. It was therefore considered desirable to devise an alternate method which would eliminate these difficulties without introducing others that would be equally troublesome. This note describes the design of an electronic timing device which has been incorporated in the analyzer constructed by the Field Research Laboratories of Magnolia Petroleum Co. The electronic timer circuit is built around a simple neon glow tube relaxation oscillator, the complete circuit diagram of which is shown in Fig. l. The operation of the circuit is as follows: Condenser C, is charged to the critical firing voltage of the neon glow tube VR-75 by battery B1 through resistors R1 and R2. When the neon glow tube fires, the condenser C, is discharged, The charging cycle then repeats itself,

Jan 1, 1950

By Thomas M. Plouf

Flotation, as we know it today, is a physiochemical method of concentrating finely ground ores. The process involves chemical treatment of an ore pulp to create conditions favorable for the attachment of certain mineral particles to air bubbles which are carried to the surface of the ore pulp for removal. Frother reagents, combined with air and the agitation mechanism, produce the effective bubbles in a flotation cell. A method of analysis is presented to evaluate the effect of frother reductions and additions on a bank of flotation cells, and to economically determine if and to what extent frother reductions and additions are justified. Comparative evaluations of different frother systems, as well as the amount of frother used in a given flotation machine, cannot be made on the frother cost alone. An indepth study must be made to evaluate any given frother as applied to a particular ore body. The recovery of a given mineral is as dependent on the amount of frother as on the type of frother used. An actual case study follows in which the amount of frother required by two different flotation machines was used to make a decision as to which unit performed more efficiently based on costs. This same method may be used to evaluate new frothers as well as to determine if a larger frother addition is advisable.

Jan 11, 1975

In a letter to the Secretary, Sir Robert A. Hadfield encloses a statement of the terms and conditions under which his prize is to be awarded by the Institution of Mechanical Engineers, and also a table comparing the hardness of a large variety of steels, examined both by Brinell and by scleroscope methods, together with the tensile and compressive strength of the same specimens. The conditions for the award of the prize are as follows: SIR ROBERT HADFIELD PRIZE For a new Method of Determining the Hardness of Metals 1. Sir Robert A. Hadfield, D. Sc., D. Met., F. R. S., Vice-President, has placed in the hands of the Institution of Mechanical Engineers the suns of £200, which, with any income therefrom, may he awarded at the discretion of the Council of the Institution as a prize or as prizes, for the description of a new and accurate method of determining the hardness of metals, especially of metals of a high degree of hardness. 2. The ordinary tests of hardness, such as are described in the report of the Hard-ness Tests Research Committee (Proceedings of the Institution of Mechanical Engi=neers, 1916, pages 677 to 778), which should he consulted by competitors, fail to some extent when the hardness of the material exceeds about 600 to 800 Brinell. What is

Jan 3, 1918

By Alvin F. Kroll

BUNKER Hill & Sullivan Mining & Concentrating Co. has three major sources of ore at present: high grade square-set ore, low grade caving ore, and low grade reclaimed washed jig tailing. These three ores constitute the feed to the 3000-tpd concentrator that produces lead-silver, zinc, and pyrite concentrates. Each ore has different characteristics of grindability, mineral particle size, composition, and content, but all are amenable to the same mill circuit and reagents. The gangue is primarily quartzite. The Bunker Hill concentrator is now using a coarse primary grind followed by a regrind of sand fractions of lead rougher tailing, lead middling, and lead cleaner tailing, and further regrind of sand fractions of zinc middling and zinc cleaner tailing. This is done in order to recover all valuable minerals at the largest size possible. The tendency to overgrind the ore particles, which are more easily ground than the gangue particles, is thereby reduced-lessening their loss in the flotation tailings. The coarse primary grind and regrind method has the advantages of: providing more selective grinding, minimizing sliming, giving a cleaner lead-zinc separation, and reducing mill requirements for reagents and water. Improved lead-zinc separation raises overall recovery and also increases lead and zinc recovery in the respective concentrates by keeping middling particles out of concentrate and tailing.

Jan 6, 1954

By R. R. Van Valkenburch

IT has always seemed to me that mining methods are inventions that follow necessity. I have yet, to be connected with a property where the consultant who has been engaged has laid out a mining method that has been strictly adhered to through the life of the mine. Possibly there are exceptions. As a general rule, perhaps, the method becomes the result of sad experience. I suppose if a person were to attempt to measure the tendency to get away from shrinkage stoping, he would need to send out a questionnaire and expect to receive truthful answers, and, having compiled the results, I think we would find that throughout the country there would be but few cases where present value of product permits the old original so-called shrinkage method to be followed. The method that I had hoped to hear Mr. Fozard expound is strictly an adaptation of shrinkage. Cav-ings do not enter. It was developed by Mr. Fozard and his staff at the Beatson mine of the Kennecott Copper Corp., at, Latouche, Alaska. Stephen Birch, in the TRANSACTIONS in 1923, submitted a brief paper on the mining at Beatson. He stated that a new adaptation of shrinkage was being tried because, although at sur-face the copper .content had been relatively high, at lower levels, in the mine it had decreased.

Jan 5, 1927

The high-grade orebody at Miami was mined successively by top-slicing, shrinkage, stoping and under caving. The method described in this paper was developed to enable the low-grade orebody (36,000,000 tons assaying 1.06 per cent copper) to be mined at a low cost without further dilution of the grade. The method is clearly described and illustrated by drawings and photographs, and the original paper should be consulted as it is impracticable to abstract it, beyond noting that the mining cost is just under 40 cents per ton and the average grade of ore now being produced yields less copper than the mill tailing of 1915, the tons mined per day having increased from 4000 to 18,000 in the same period. Vertical and Incline Shaft Sinking at North Star Mine By Arthur B. Foote, Grass Valley, Calif. (Tech. Pub. No. 324: Class A. Metal Mining, No. 36) THE main shaft of the North Star mine is an inclined one following the main vein at an average dip of 26 deg., a vertical shaft intersects it at the 4000-ft. (incline) level, the incline continuing to the 6300-ft. level. At this point the vein was found to give out and a new vein, called the No. 1, was found to dip in exactly the opposite direction.

Jan 1, 1930

Where Does the Mine Dollar Go? BY PAUL M TYLER (Min & Met, April, 183 3900 words) Wage earners on the job get nearly 50 per cent of the mine dollar; salaries normally take over 5 per cent (less for large metal mines); and less than 20 per cent is expended for supplies, materials, fuel, and power The total of all such specified expenditures, which may be loosely described as "direct costs," has tended over several decades to decline from over 75 per cent to under 70 per cent of the gross receipts from the sale of products of mines and quarries The item of supplies and material is far less important in the extractive industries (mines, forests, and fisheries) than in manufacturing For manufactured products the average cost of raw materials was 30 4 per cent of gross sales, almost double the proportion for the mineral industries, whereas factory wages and salaries accounted for only 33 2 per cent instead of 51 9 per cent Within reasonable limits, the margin above direct costs as herein calculated affords a measure of capital's share in the total realized from sales A preponderant group of mineral industries operate under conditions that permit or require a margin of 25 to 45 per cent At one end of the scale are highly organized industries such as sulfur, fuller's earth and iron ore mining employing much

Jan 1, 1935

FOLLOWING- the major explosion disaster in the Orient No. 2 mine of the Chicago, Wilmington and Franklin Coal Co., West Frankfort, Ill., on December 21, 1951, resulting in the death of 119 miners, an investigation was made by the U. S. Bureau of Mines under the direction of J. J. Forbes, Bureau director. The subsequent report concluded that the disaster. was caused by the emergence of a-large body of explosive gas from an abandoned area and simultaneous short circuiting of the ventilating current; the gas was ignited by an electric arc from nonpermissible electrical equipment and the flame was propagated throughout a large part of the affected area by coal dust and possibly by gas from other worked-out and abandoned areas. An immediate repercussion of the disaster was the opening of hearings by the. Senate Labor and Public Welfare Subcommittee on the Neely Mine Inspection Bill (S. 1310, introduced April 11, 1951) which would give federal coal-mine inspectors power to enforce safety recommendations by ordering the withdrawal of all employees where conditions constitute an imminent danger to their safety. Two days of testimony, January 24 and 25, disclosed that coal operators were not in agreement on the bill, although John L. Lewis, speaking for the UMWA, and J. J. Forbes, for the Bureau of Mines, were advocates.

Jan 1, 1952

By Robert L. Grayson, Y. J. Wang, R. Mike Mishra

Prediction of ventilation needs in long range mining projections requires serious consideration when formulating those projections. Predicting the behavior of the ventilation system of an old, complex mine poses an especially provocative problem. Air-flow around and through mined-out areas via bleeder systems, leakage flows through stoppings or other air control devices, and the use of multiple fans all add to the basic complexity of a ventilation system and make predictions of ventilation changes very difficult. Fortunately, the task of making ventilation decisions can be greatly assisted by ventilation surveying and computer simulation. The Nemacolin Mine of Jones and Laughlin Steel Corporation, located in Southwestern Pennsylvania, is one such old mine which used the computerized approach successfully. A mine-wide pressure-quantity survey was used to obtain realistic values for airway resistance factors. These values, together with network topology, formed the basic input for computer simulation. Results from this simulation indicated that air quantities generated at critical airways by the model were generally within a couple of percent of those measured in the actual survey. It was then concluded that the model was acceptable for practical application, and it was used immediately for studying the effects on the ventilation system of changing the blade settings of fans. Additionally, the model was modified to incorporate projected mine development and used to predict future ventilation.

Jan 1, 1982

By John Dasher

Extrapolation is a useful technique, but it can be overdone. Seldom is it justified to study over a range of 1 to 6 and extrapolate the results to 150,000. It is especially dangerous if the extrapolation is based on a false assumption. The authors assume settlers scale-up by residence time rather than by area, admit their result (a settler depth of 7 m) is "unreasonable" and suggest longer, wider, shallower settlers might be better. Various authors have noted for a copper-LIX system a total flow basis of 2 gpm per sq ft for sizing settlers. The results of this are compared with those in the paper in [Table 7]. The authors note that flooding of their settlers was never approached. Thus the smallest unit calculated is understandably twice too big. The largest however, is 5% of the required size. I note that the figures in [Table 6] for 1/min/cm2 are based on plan area rather than cross section as titled and are wrong by l0 4. A flow of 2050 1/min/cm2 is about Mach I. It is also 10 5/3 or 46.5 times that of the little one, although the abstract says the design was based on constant flow rate per unit cross section.

Jan 1, 1977

By Robert A. Rapp

The standard molar free energy of formation of MOO,was determined between 750o to 1050o C in galvanic cell measurements involving the solid electrolyte Zr0.85 Ca0.15 O1.85. Use of the reference electrodes Fe + FexO and Ni + NiO Provided two independent determinations of FoMoo2. The data may be represented by the equation FMoO2 = -137,500 +40.0T(°K) which is in good agreement with previous CO/CO, gas equilibrium measurements of Gleiser and Chipman. The standard molar free energy of formation of molybdenum dioxide has recently been reported over a large range of high temperatures from the calorimetric experiments of King, Weller, and christensen.' Gleiser and chipman2 have also recently determined ?FmoO2 from 926o to 1068oC in CO/CO2 gas equilibrium measurements. Earlier gas equilibrium studies have been made and reviewed by Gokcen.' Over the temperature range studied by Gleiser and Chipman their values for ?FoMoO2 differed from the calorimetric data by about 700 cal. This investigation was undertaken to resolve this difference and thereby establish the two phase mixture of Mo + MOO, as an electrode of well-known oxygen potential for galvanic cell applications at very high temperatures. The galvanic cell technique involving the Zr,.,, Ca,0.15 01.85 solid electrolyte was introduced for the

Jan 1, 1963