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By H. N. Eavenson

In a discussion in the Transactions of the Institute (vol. Xl, page 835 et seq.) the writer gave some data about the explosions of gas and dust in the coal mines of the United States, Canada, and Mexico…

Jan 1, 1915

By Sidney L. Wise, Walter Strache

While the installation of mine bulkheads to retain water under high pressure is by no means a rarity, the following points which arose in the designing and placing of two of these bulkheads may be of interest: The Hibernia magnetite mine, located about 40 miles west of New York, in the State of New Jersey, is partly fillcd with water. This mine is located on an ore lens, the outcrop of which is over a mile long. The ore has been mined from this lens from the surface to a depth of more than 1,500 ft. It was held desirable to separate the old workings from the new, and to allow the former to fill to the 850-ft. level. Two weak places existed between the new and old workings below this Ievel: namely, a temporary bulkhead on the 10th level and a rock bulkhead of indeterminate thickness on the 16th level. When the matter of allowing the old workings to fill was investigated, the fact was developed that if these old workings were filled, the bulkhead on the 10th level would be subjected to a water pressure of about 50 lb. per square inch, and that 200 lb. per square inch would act on the 16th-level bulkhead. As the above-mentioned barriers were not deemed of sufficient strength to permit of these pressures, it became necessary to design and install new bulkheads. Design As the 16th-level bulkhead was required to withstand a pressure of 200 lb. per square inch, it presented some difficulties. A careful consideration of the various types of mine dams now in use led to the adoption of a design of the form of a truncated wedge. In this, the pressure side of the dam is of greater area than the hack, so that the resultant action is similar to driving the wedge. By cutting generous skewbacks in the walls, roof, and floor, this type in reality becomes an invisible arch. The wedge feature tends to compress the materials in the bulkhead, thereby adding to its imperviousness.

Jan 1, 1915

By A. C. Boyle

PaGE I. Introduction.........68 II. Location of the District,....... • 70 .. III. Stratigraphy...........73 Description of the Rocks.......73 Triassic Eruptives (Andesite Flows and Tuffs) ....73 Triassic Sediments (Shales and Slates)..75 Areal Geology ............75 Structure...-.......76 Folds............. 76 Faults..........79 Shear ...........80 Intrusives..........81 Alaskite Dike.........81 Andesitic Intrusion.......82 IV. PetrogRaphy of thE Rock Types......83 Andesite Flows.........84 Tuff 8...........84 Andesite Tuff........84 Rhyolite Tuff.....-.......85 Alaskite-Porphyry.......89 Andesite Dike........91 V. Description of the Mines......92 VI. Metalliferous Deposits ........ 95 Character of the Ores...........97 Mineralogy of the Ores.......97 Metallic Minerals.......97 Microscopic Character of the Ores...98 Secondary Enrichment....... 103 Genesis of the Ores ...........104 VII. The Sulphate Deposits.......109 Gypsum ..... HO Anhydrite......... ,... 110 Barite............ 110 Origin. with special reference to Gypsum....111 VIII. Summary.............. 113 IX. BIblYogRaphY.............114

Jan 1, 1915

By Douglas Bunting

The first presentation of this paper was before the Pennsylvania Anthracite Section of the Institute in May, 1914, after which a committee was selected to verify and add to the data contained in the original paper. The author is indebted to G. W. Engel, H. W. Montz, R. V. Norris, and H. H. Otto, of this committee, for additional information. I also wish to acknowledge the courtesies extended me by a number of the mining companies for information relative to accidents, systems of proving, and mining practice. The paper should bring forth additional criticism and recommendations, which will be of value in establishing future practice relative to this subject. Throughout the northern anthracite field of Pennsylvania glacial and alluvial deposits of sand, gravel, and clay exist in varying quantities. The extent and character of these deposits are described by N. H. Darton in Bulletin 45 of the U. S. Bureau of Mines, entitled, Sand Available for Filling Mine Workings in the Northern Anthracite Basin. It is estimated that the northern field contains 10,000,000,000 tons of these deposits, or a sufficient quantity to cover the 176 square miles of coal area to a depth of about 25 ft. These deposits of sand, etc., overlying the coal measures attain a maximum depth of more than 300 ft., and are usually saturated to such an extent as to render them semi-fluid. It is this condition of fluidity that limits the mining of coal seams cropping in or in close proximity to these deposits, and it is in the interest of safer and more efficient mining methods under these conditions that the study of this subject is here presented. The dangers incident to mining under deep deposits of sand have long been realized by operators in the northern anthracite field, and much has been done to prove the contour of the rock and vein croppings underlying these water-bearing deposits of sand and gravel. Although, as far as we know, the accidents of the past have not resulted in the loss of life, except in two instances, yet nearly all were attended with more or less miraculous escapes of men working in the vicinity of the breaks, so that the probable existence of pot holes, etc.,

Jan 1, 1915

By W. F. Schwedes, S. S. Rumsey

In order to realize the enconomics which would result in operating the mine pumps at the Chapin mine with electricity generated by water power, the Oliver Iron Mining Co. recently installed a hydro-electric plant at the upper Quinnesec Falls on the Menominee river, and constructed a transmission line to the mine.

Jan 1, 1915

By Albert E. Wiggin, Frederick Laist

Page I. Introduction............................470 II. The Sources and Amount of Slime................470 II. The Composition of the Slime..................471 IV. The Experimental Development of the .Anaconda Slime Plant.. 471 1. The Great Falls Slime Plant and Experimental Work......471 2. The Experimental Work Done at Anaconda..........473 (a) SlimeThickening Devices.............. 474 (b) SlimeConcentrators................. 475 (c) Dewatering the Slime Plant Concentrate......... (d) The Use of Chemicals to Accelerate the Settlement of Slime........................ 478 (e) The Effect of Temperature upon the Settlement of Slime 478 V. A Description of the Anaconda Slime Plant........... 479 1. A Diagrammatic Flow Sheet of Plant............. 480 2. The Slime-Thickening Division................ 480 3. The Concentrating Division.................. 481 4. The Concentrate-Dewatering Division............. 483 5. General Data........................ 484 I. IntRoduction The new slime-concentrating plant at the Washoe Reduction Works, Anaconda, was put into operation during March, 1914. This plant, which has a capacity of 26,000,000 gal. of slime pulp carrying 2,500 tons of solid matter per day, consists of Dorr thickeners and Anaconda multiple-deck slime concentrators. This plant is the culmination of a great deal of experimental work extending over a considerable period of time, which , work will be described briefly in the following pages. II. The Sources and Amount of Slime Up to the beginning of this year, the ore from the Anaconda company's mines in Butte, Mont., has been concentrated both at the Great Falls

Jan 1, 1915

By Edgar L. Newhouse

The lead smeltery at East Helena, Mont., controlled by the American Smelting & Refining Co. since 1899, has been in continuous operation for the past 25 years. Most of the old smelting and roasting practices have been superseded by newer and more modern methods, but on account of the difficulties involved in changing the original construction, some of the methods in use of handling materials are not the most modern. This plant, however, is particularly interesting as being one of the few essentially lead smelteries in the United States. At Federal, Ill., Collins-ville, Herculaneum, and possibly other places, similar work is being done, but it is doubtful whether any of them produces as much lead as the East Helena plant, whose monthly production averages 6,500 tons. The situation, 5 miles east of Helena, is convenient to both the Great Northern and Northern Pacific railroads, while the electric power is obtained from Canyon Ferry, 12 miles east on the Missouri river. Local quarries supply the requisite amount of lime rock, which the contracts require to be crushed to 5 in. Of the 450 men on the monthly pay roll, a census showed 200 Austrians, 110 Americans, and 30 Italians, the balance being made up of miscellaneous nationalities. The ore supply is mainly derived from the Coeur d'Alene mines in Idaho, and consists of crude ore, coarse and fine concentrates, middlings, and slimes. About one-half of the total output of the Coeur d'Alene camp is sent to East Helena. An average analysis of these ores gives approximately 40 per cent. lead and 11 per cent. sulphur. Local shipments, varying from month to month, are mostly highly siliceous gold and silver ores carrying little lead. Small shippers, leasers of old mines, and prospectors are very numerous throughout Montana, and it is the policy of the company to encourage these men by every possible means, including the free sampling and analysis of their ores and aid in the development of their mines and prospects, whenever their results show promise.

Jan 1, 1915

By C. D. Keen

In the latter part of the summer of 1913 the Conservation Commission of the State of Louisiana, under presidency of M: L. Alexander, decided to stop the waste of natural gas going on at the "burning gas-well," Located about 2 mile southeast of Oil City, La. On several occasions, both in newspapers and in reports, comment had been made on the condition of this well, its harmful effect on the Caddo gas field, and the considerable loss, estimated at several thousand dollars each month, caused by the escape of the valuable fuel., But nothing had been done to bring the well under control and prevent further waste of gas until the State Conservation Commission took the matter in hand. The gas fields of Louisiana are among the greatest in the country. So far most of the gas has been found in the Caddo field proper, although considerable development has been done in and around the city of Shreveport and near the town of Mansfield in DeSoto parish. To extend the life of the gas fields and to prevent the quick exhaustion of the supply of the natural fuel are matters of vital importance for this section of the country. Four gas companies have entered the Caddo field and supply the surrounding towns and cities With gas. The Arkansas Natural Gas Co. has pipe lines to Little Rock, Ark., and supplies gas to the following cities and towns in that State: Texarkana, Hope, Garland, Emmet, Prescott, Boughton, Beirne, Gurdon, Arkadelphia, Gum Springs, Mal-vern, Dsnaldson, Gifford, Perla, Beaton, Beauxite, Mabelvale, Bryant, Sheridan, Pine Bluff, Little Rock, Argenta, Pulaski Heights, and Hot Springs. The Southwestern Gas & Electric Co. transports gas to Mooringsport, Blanchard, Caddo, Rodessa, Oil City, Vivian, Bloomburg, Hosston, Ida, Dixie, Belcher, and Shreveport. The Marshall Gas Co. supplies gas to the town of Marshall, Texas. The Louisiana Co. has a line to Shreveport. In, the oil field the gas is used for drilling purposes, and the operators either have their own gas system or buy from the gas companies. At the present time the surrounding territory depends for its fuel supply on the Caddo field, and the importance of the conservation of the natural-gas

Jan 1, 1915

By G. S. Rice

The subject of dust explosions in coad mines first appears in the Transactions of this Institute following the first great mine disaster that happened in…

Jan 1, 1915

By Howland Bancroft

The writer has observed that some confusion is experienced by many mining engineers in making vertical sections of ore deposits in mining properties which they have examined. Having much examination work calling for the correct interpretation of vein structure and the subsequent platting of the same on sections, it has occurred to the writer that the accompanying diagram may be of use to others who at times may be called upon to prepare numerous sections. For example, a great mass of data on strike and dip of ore bodies is collected underground in separate

Jan 1, 1915

By Charles Legrand

In many iron, coal and copper mines where large tonnages are known before starting operation and proper provisions can be made, the problems of electric traction by trolley locomotives are not very different from those of surface plants. In such installations the gauge of the track, the radius of curves, and the clearances, both vertical and horizontal, can be made to suit the conditions of the traffic. It is more difficult to install electric traction in mines which were started with hand tramming and where no consideration was given to the possibility of mechanical traction being used. The writer having had some experience in the installation of electric traction in copper mines, the following remarks apply more particularly to these mines. With the gauge of track usually 18 or 20 in., the weight limit of locomotives obtainable from manufacturers in this country varies from 3 to 6 tons. The full-load speed varies from 49 to 6 miles per hour. These locomotives, being made to run on very small radius curves, have a short wheel base and a long overhang from axle to coupling, which necessitates a coupling' with a good deal of lateral motion to avoid derailing the cars on sharp curves, especially if couplings are of the standard railroad automatic type. Although 3-ton locomotives will run on 12- or 16-lb. rails, it has been found more satisfactory to use 25-lb. rails, as the track keeps in much better shape, it is easier to maintain the bonding in good order, and fewer derailments from dirt on the track occur with the larger rails. Where 6-ton locomotives are used the 25-lb. rails are satisfactory, but 40-lb. rails have proved cheaper where the traffic is heavy and the ground is soft, as the track maintenance is considerably lower with the heavy rails. The locomotives will run on 15-ft. radius curves, but on through runs it is advisable not to go below 40-ft. radius. The voltage used should not exceed 250 to 275 volts, and the trolley wire should be protected, to prevent accidental contacts, in front of chutes and at all points where it is low. With the air lacking somewhat in oxygen and the heat and high humidity prevalent in many mines, this

Jan 1, 1915

Jan 1, 1915

By Albert Burch

The theory of the present law with reference to lode locations contemplates the existence upon the surface of mineral-bearing veins which have clearly marked boundaries, and which can be so readily traced that a locator may immediately mark the boundaries of his 600 by 1,500 ft. claim in such a way that the vein will 'pass through both of its end-lines. It also supposes that, having discovered such a mineral-bearing vein, the locator will at once post a notice upon such discovery, mark the boundaries of his location in such a manner that they can be readily traced, and from that time forward have absolute title to the ground embraced within such boundaries, as against every person except the United States. For initiating title to placer ground, the law presupposes the discovery of a valuable mineral deposit; but not necessarily in place, as in the case of lode claims; and the location must be made to conform "as nearly as may be" to the legal subdivisions of the United States public land survey. When the placer law was extended to include the acquisition of title to oil lands, no exception was made as to the necessity for the discovery of valuable mineral in advance of location! Practice under the Present Law Nature did not make all veins clearly defined and readily traceable upon the surface; nor did she, in all cases, leave upon the surface which overlies important ore bodies such outcrops as would in them-selyes be considered valuable; and the citizen of the United States has in the past endeavored to steer his course between the mandates of the law and the limitations of nature. Until quite recently, it has been possible to obtain a patent for any-

Jan 1, 1915

By Carl A. Allen

Page Introduction................... 367 FactoRs Affecting the Choice of Method......... 367 Review of Stoping Methods.............. 368 Underhand Stoping................ 368 Overhand Stoping................ 370 Longitudinal or Flat-Back Stoping........... 371 Rill-Cut Stoping................. 372 Saw-Tooth Back Stoping.............. 372 Shrinkage Stoping................ 372 Combination Stoping................373 Side Stoping.................. 374* Breast Stoping................. 374 Sublevel Stoping.........,....... 374 Square-Set Stoping................ 376 Filling Methods................. 376 Caving Methods of Mining......... 376 Top Slicing.................. 377 Sublevel Caving................. 379 Block Caving ................. 380 Back Caving into Chutes.............. 381. Costs of Mining Methods.............. 382 Costs of Willing and Blasting. Comparison of Stoping Methods ... 383 Lighting................... 386 Timbering and Handling Ore in Stopes.. A Comparison of Square-Set and Top-Slicing Methods..............386 Tramming.................... 380 Mining oF the Massive Porphyry CoppeR Deposits ....390 Utah Copper and Boston Consolidated Mines.....391 Ray Consolidated Mine.............. 392 Miami Mine.................. 392 Inspiration Mine................ 395 Ohio Copper Mine...........395 Development.................... 398 Appendix..................... 399 Costs of Mining................. 399 Costs of Development............... 406

Jan 1, 1915

By Joseph P. Hodgson

In 1880, mining operations were commenced at the Copper Queen mine. The famous Queen ore body, which extended to the surface, was first quarried from a large open cut in the outcrop. The ore body was followed down to the 300 level with the Queen incline, and stoped. This, we believe, marks the introduction of square setting in the Bisbee district, which is still the method most generally used. Orebodies The orebodies in the Copper Queen mine occur in the limestones, and the main portion of the ore has been mined from the Abrigo, Martin, and Escabrosa limestones. mile the orebodies outcrop in the extreme western end of the mine, the general dip is to the east and south, at an angle of about 20°, although this dip is not by any means regular, being, in fact, very irregular locally. The ore is remarkable for its variableness in character, some of it being very soft, requiring a large amount of timber, and other portions consisting of extremely hard sulphides. The orebodies, in general, while remarkable for their continuity, are very irregular, both as to shape and size. The mine having been in operation so many years, and mining having been prosecuted over such a large area, the operations have caused the shrinkage of the overburden, and there is a constant movement, which is shown by large cracks and interstices in the surface rocks, which largely contribute to the very high deadwork or maintenance cost of the mine. It is surprising that for year 1913 it cost almost $400,000 just for the one item of repairs and dead work in this property. Haulage and Hoisting The underground openings have been extended in the neighborhood of 200 miles. The ore hoisting is performed at a centrally located shaft, the Sacramento, to which all the ores from different parts of the mine are conveyed by electric haulage, of which there was slightly over 9 miles in operation in 1913. The hoisting levels at the Sacramento shaft are placed 200 ft. apart, commencing at the 400 level and continuing down to the 1,600 level, the average hoisting distance being 1,000 ft. The

Jan 1, 1915

By Arthur B. Foote

The cams at present universally used in stamp mills lift the tappets with an involute form of curve, to which the surface of the tappet is always tangent; moreover, the line of contact between tappet and cam, if produced, would pass through the center of the stem. This is no doubt a desirable feature, but the writer has long believed that it would be much more desirable if the cam were to pick up the stamp without shock, and gradually increase the upward velocity of the stamp throughout its upward movement. The involute form of cam attempts to impart instantly a considerable upward velocity to the stamp, starting it from a state of rest, and the result is a destructive blow, a great deal of noise, and much wear and vibration. The writer has developed a form of cam which will lift the stamp pith a motion similar to that of the piston of an engine between the end and middle of its stroke; in other words, harmonic motion, from the woint of zero to maximum velocity. The curve will give this ideal motion only when the stamp is set for the exact drop for which the cam was designed, but the improved cam will not be as bad as the involute cam until the drop is reduced one-half. In other words, if a cam is designed for a 6-in. drop, it will be some improvement over the usual form of cam until the drop is only 3 in. Any cam, whatever its form, must of course lift the stamp in the same number of degrees of revolution; therefore, with this new form, since the stamp starts more slowly on its upward course, it must end up by going faster, the average speed being the same as with the involute cam. The stamp, after it is no longer in contact with the cam, keeps on going up a certain distance, which is easily calculated. It is therefore possible to hang up a stamp without a cam stick, if the fingers are not more than + in. longer than necessary to hold the tappet above, the cam. With this design of cam the surface of the tappet is not tangent to the surface of the cam throughout the lift. The possible consequences of this were studied with a full-size model, and did not seem serious, as

Jan 1, 1915

By C. D. Demond

In reverberatory smelting, fuel is the chief item of expense, as it commonly is in processes using large percentages of it. Hence the most suitable supply is eagerly sought; that is, the supply which, in the end, yields the greatest net profit. The better grades are not infrequently bought, even at an advanced price, because they are apt to be decidedly more economical. High price, of itself, however, is no merit, for freight is generally the largest part of the cost of fuel, and the nearby supply may yield as high efficiency as that from a greater distance. If a poorer grade is reasonably good, and if its cost is low enough to more than offset the decreased technical efficiency, it is of course the more suitable. Any smelting operation depends for both efficiency and economy on raising the furnace atmosphere considerably above the "critical" temperature; that is, above the temperature at which smelting is completed. If this temperature is not exceeded, smelting stops, no matter how much coal is burned; and the real value of a fuel depends on the number of degrees that the temperature is continuously kept above this point. For example, if one fuel maintains 2,500" F. and another only 2,100 F., while the "critical" temperature is 2,000" F., the first is worth at least five times as much as the second, although the increase above atmospheric temperature is only one-fifth more in one case than in the other. This "margin of temperature" above the smelting point is much more significant than the total number of heat units developed from the fuel. The case is parallel to that of water flowing from a pipe. The reservoir may contain a billion gallons of water; but, even though the fluid has come to the nozzle, not a drop will run out, where it can be of practical use, unless the level in the reservoir is higher than the nozzle; and the speed and volume of flow depend on how much higher the level is in the reservoir than at this point. If the temperature in a furnace is not above the critical level there will be no slag to flow over the skimming plate, even though there are enough heat units to bring an unlimited quantity of charge up to the point of slag formation; and just as the value of a water supply for the purpose of putting out a fire depends largely on the effective head, so the difficulties of furnace management

Jan 1, 1915

By Charles T. Malcomson

In the United States, improvements in methods of combustion have made possible the use of the smaller sizes of anthracite. This coal is now being reclaimed from the culm banks accumulated by the miners in the more prodigal years. To-day the freshly mined "slush" is segrega,ted and stored against the time when, through briquetting or some other means, it may be utilized as a commercial fuel. For many years Europe has achieved enviable results in the conservation of her small coal by briquetting. This profitable industry, first placed on a commercial basis in France in 1842, has grown to such magnitude that the production during 1913 exceeded 36,000,000 short tons. Briquets produced in Great Britain are used principally for steam purposes and the greater part of the output is either exported or taken by the Admiralty. On the Continent the briquets are sold in all branches of the coal trade. The French railways consume from 16 to 40 per cent. of their fuel in briquet form, and in Germany the lignite briquets (of which 20,000,000 tons were produced in 1913) are as familiar and interesting to the American traveler as the huge porcelain stoves in which they are burned. It is not strange, therefore, that aggressive and far-sighted promoters heralded this means of converting our ubiquitous coal waste into revenue. To the superficial student the briquetting process seemed so simple as to make success easy. It is for this reason principally that the path of the industry in America has been strewn with failures. The rash enthusiast had either not worked out the mechanical problems involved or had failed to grasp the local conditions under which the briquets must be made and sold. It may be confidently stated, however, that in spite of the many vicissitudes through which it has passed, coal briquetting is now an accomplished economic success in this country, and as a profitable adjunct to the coal industry it has come to stay. Several valuable contributions relating to coal briquetting are found in the Transactions. Charles Dorrance, Jr., has sketched briefly the history of the anthracite briquetting plants from the time of Loiseau's pioneer plant down to that of the Lehigh Coal & Navigation Co. at Lans-ford. Since then this phase of the industry has remained practically at

Jan 1, 1915

Jan 1, 1915

By Robert Linton

The Sierra Consolidated Mines Co., organized in 1909, owns, together with other holdings, practically all of the productive mineral area in the Ocampo district. Lying within this area are 15 mines, large and small, that hid previously been worked and appear to have yielded, since the discovery of the camp, about 100 years ago, bullion of a total value of over $50,000,000. The deepest mine, the Santa Juliana, had been worked to 1,100 ft. below the outcrop. The reopening of the mines involved, first, extensive and thorough development to open up the known ore shoots at greater depth and explore the ledges for additional shoots, and, second, a revision of existing equipment and methods, so as to increase output and reduce cost of production. This paper will give some account of the metallurgical treatment and a description of the new mill to be built at El Salto. The Ore The ore is practically all argentite, Ag2S, with some associated gold, and carried in a siliceous gangue. The typical ledge matter is an ande-sitic breccia cemented with quartz, or quartz stockwork in andesite.l The proportion by weight of silver to gold averages about 60 to 1. The silver sulphides occur ordinarily in rather fine. dissemination, sometimes not being easily discernible with the naked eye, even in ores of very good grade. The ledges also contain considerable pyrites, which as a rule is barren. "Bronce" is the local term applied to such barren pyrites, and "Pasta" to such as carries values.

Jan 1, 1915