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By Edward Martinez

The literature on the beneficiation of serpentine asbestos ore states that the specific gravity of the rock containing fiber and the fiber itself is the same so that specific gravity cannot be used as a basis for separation. An investigation of particles of asbestos ore ranging in size from 4 mesh to 5 in. revealed that the fiber-bearing particles generally had a lower specific gravity compared to essentially barren particles. The difference in specific gravity was sufficient to make an effective gravity separation of ore particles and reject a low grade tailings product. The results of laboratory tests are described that lead to the running of pilot plant tests with 20-ton ore samples using a heavy media separator. These tests indicated that a large amount of low grade material could be rejected from the raw ore at a coarse size. Although the process used is a wet separation, it can be added to a conventional dry asbestos mill. A gravity preconcentration would allow the mining of lower grade ore, increase the life of the mine, increase the value of the feed to the fiber recovery section, and decrease maintenance costs by removal of low grade tailings early in the flowsheet.

Jan 1, 1975

By Albert Burch

AN analysis of this subject demands a study of the theory and practice of the present system, conclusions as to its merits, and recommendations for remedying its defects if any be found. Theory of the Present Law 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!

Jan 6, 1914

By A. V. Quine

FOUR years ago several mining operators shook their heads and predicted that Goldfield Consolidated Mines Co. would never be able to mine the zinc-lead ores from the 550 to 650 level areas of the Deep Creek mine. Their prediction was not without apparent justification, for everywhere one gazed, water was spurting or dripping; every hole that was drilled produced more and more water under pressures of 220 to 250 psi, all from apparently unrelated channels. When the volume of water from one level alone reached 2200 gpm with a possible flow of 5000 to 6000 gpm if the area were fully tapped, development work was brought to a halt and the few holes into the water area were grouted off under contract. As zinc prices had completely deteriorated, the workings were allowed to flood. Upon reopening the mine, in late 1950, it was discovered that the relatively few sacks of cement used in the previous grouting operation had done a tremendous amount of good. Consequently it was decided to systematically drill test holes with a longhole machine and diamond drill and to seal all holes with a cement grout solution. After 30,000 ft of drilling, and the pumping of over 20,000 sacks of cement, 15,000 of which were placed in the supposedly impossible 650 level, the company was successful in literally forcing the water out of the ore zones and opening up large tonnages for subsequent extraction.

Jan 3, 1954

By Arthur C. Simmons

The area that produces Pennsylvania grade, which includes New York, Pennsylvania, West Virginia and a part of Ohio, increased its production in 1942 about 1,580,000 bbl. over that attained in 1941. Such an increase is substantial for this area, and measured in terms of increased output of lubricants, for which the crude is particularly suitable, it represents a needed arid worth-while addition to the lubricant resources of the United States. The year 1942 was a difficult operating period for most of the petroleum-producing areas in the United States, but the Appalachian region, owing principally to its location, type of operations, and crude value, suffered less from war influences than other areas. The state of Pennsylvania produced 17,823,870 bbl. of crude oil, which is approximately 63 per cent of the total production of Pennsylvania grade in the entire area. Production Bradford Field The Bradford field, which produces almost wholly by water-flooding methods, increased its production nearly 4000 bbl. per day over 1941 despite a very slight reduction in total number of wells completed. Well completions in the Bradford field (in both New York and Pennsylvania) includc both producing oil wells and water-intake wells. About half of the well completions are producing oil wells and the remaining half are water-intake or injection wells. About 10 per cent of the total well completions of the Bradford field were in Cattaraugus County, New York. No segregation of well completions is available, so that precise statistics cannot be given for New York and Pennsylvania.

Jan 1, 1943

C. A. Stetefeldt, San Francisco, Cal. (communication to the Secretary): In view of Mr. Louis's statement that the balance and weights employed in his experiment were '(by no means first-rate," the results can scarcely be entitled to weight. And if a slight variation in specific gravity were to be accepted as proof of the existence of allotropic modifications, we should be obliged to conclude that every metal existed in such modifications. When the observed specific gravity of an alloy (as is often, and perhaps generally, the rase) differs from the calculated one, it seems more reasonable to explain the difference (apart from errors of determination) by assuming that actual chemical combination takes place between some atoms of the metals. MR. Louis (communication to the Secretary): In reply to the criticisms with which Mr. Stetefeldt has favored me, I beg to point out to him that, in the first place, I do not myself attach very much weight to the results I have obtained. I merely claim to have pointed out that amorphous gold obtained from dissolving up the alloy with silver has a higher specific gravity than common gold—a result corroborated by the quoted results of Rose. At any rate, it is easy to repeat my observations, and I hope this may be done by men who have better opportunities than myself for this investigation. Surely it is worthy of attention from assayers at the mints. I am not prepared to say that I should regard slight variations in specific gravity as absolute proof of allotropism, but I do consider

Jan 1, 1894

By W. R. Ingalls

THE MAJOR use of spelter has always been for the coating of iron and steel products, the process of coating being known as "galvanizing" and the products themselves as "galvanized," except for a couple of years during the war, when the consumption for brass making became superior, in the United States at least, owing to military demands. Since 1919, however, the consumption of spelter for galvanizing has regained the premier position, but not with such a long lead over brass making as previous to the war. The last development is ascribable to two main reasons, viz., an increased demand for brass in new industries, especially automobile manufacturing; and a diminished use of spelter per unit of iron and steel galvanized. MAJOR IMPORTANCE OF SUBJECT The last mentioned matter has already been the subject of some discussion and of some literature. The galvanizers have been charged with deliberately thinning their zinc coatings, with the consequence of producing inferior goods and thereby jeopardizing the whole galvanizing business. Zinc producers have been concerned about this, out of consideration of both the less use of zinc per unit of iron and steel and the fear that, the number of units produced may be curtailed. It has been argued, among other things, that the present policy of American galvanizers would impair their ability to compete in foreign markets with British galvanizers, who have been represented as making a superior product.

Jan 7, 1923

At their last meeting, the Directors of the Institute passed the following resolution regarding Robert W. Hunt, who was president of the Institute in 1883 and 1906. This resolution was engrossed and presented to Captain Hunt at a dinner given to him in Chicago, December 9, on the occasion of his eightieth birthday. Resolution At that time it was announced that $5000 had been guaranteed as the nucleous of a fund, the income of which will be used for prizes to be awarded each year, under the supervision of the American Institute of Mining Engineers, for the best papers on iron and steel subjects. The Board of Directors of the American Institute of Mining Engineers extend to their distinguished colleague, Robert W. Hunt, a hearty greeting upon his eightieth birthday anniversary. They congratulate him upon his notable achievements as a pioneer in ,the manufacture of iron and steel, and his long and admirable service both as a practical director and as a wise critic and counselor in that art. They remember with gratitude his successful administration, for two separate periods, of the Presidency of the Institute, and they recall with pride the honor conferred upon it through the award to him of the John Fritz Gold Medal. Not least is their satisfaction in the retrospect of forty-four years of his membership in the Institute, with its unbroken record of loyal friendship acid delightful companionship; and they pray, that this record may be continued for happy years to come. In witness whereof, they have ordered this minute to be entered upon the records of the Board, and a copy duly attested to be sent to Captain Hunt.

Jan 1, 1919

Another excellent Swedish underground crushing plant is that at Crusher Station 51 of LKAB in Kiruna, Sweden. Bottom-dump rail cars pass over a dump scroll to discharge magnetite ore into a 288 cu yd (220 m3) pocket equipped with a Hewitt Robins E-13 vibrating grizzly feeder. The grizzly section is 59 in. (1500 mm) long and has bar spacings 3 in. (76 mm) wide. Any oversize boulders which will not pass the chute opening to the feeder are blasted. The primary breaker is a Morgardshammar overhead eccentric 55 in. by 71 in. (1400 by 1800 mm) jaw crusher powered by a 200 hp (149 kw) motor. An open side setting of 10. 8 to 11. 8 in (275 to 300 mm) accounts for the high capacity of this crushing unit (2760 stph or 2500 mtph). This figure compares favorably with the capacity of many gyratory crushers but is typical of the Swedish jaw crushing installations, which are often followed by three more stages of crushing or by autogenous grinding. Crushed ore from the jaw crusher is combined with the grizzly under- size in the crushed ore pocket and is fed by a second vibrating grizzly feeder to the secondary cone crusher. Both crushers are serviced by 50/5 ton overhead bridge cranes. During maintenance operations air -operated gates shut off the flow of ore from the dump and primary crushed ore pockets.

Jan 1, 1978

By AIME AIME

For the convenience of persons who desire to file, or otherwise use separately, the technical papers in Section II of the Bulletin, each of these papers has been paged and wired by itself; the whole collection being held together by a single, heavy wire, upon the removal of which it will fall apart into individual pamphlets, substantially like those formerly issued. A small stock of separate pamphlets, duplicating the technical papers given in Section II. of this Bulletin, is reserved for those who desire extra copies of any single paper. All communications concerning the contents of this Bulletin should be addressed to Dr. Joseph Struthers, Assistant Secretary and Editor, 99 John St., New York City (P. 0. Box 223; Telephone number 5477 John).

Mar 1, 1906

The Mining Journal Annual Review. The Mining Journal, London. $1.00, 200 pp., 1952.-Contains 70 specially contributed articles reporting on events in the metalliferous mining industry throughout the world during 1951. The articles are written from the standpoints of: Economics, world mining fields, progress reports on Empire mining companies, and British mining taxation. The review has appeared for a period of 20 years. Technical developments in mining, ore treatment, refining, and metallurgy are covered. Dun & Bradstreet Reference Book. Dun & Bradstreet Inc. 4000 pp., 1952. -Changes, brought about by the expanding economy, have been made for the three million listings for the United States and Canada. Planning for the changes started more than 10 years ago. New listings have been included for the metals and mining industries on all levels. The rapid development and specialization of industry have made the old symbols used in previous editions outmoded and a new system is substituted. Atlas of World Mineral Resources, . Edited by William Van Royen and Dr. Oliver Bowles. Prentice-Hall Inc. $10.75, 180 pp., 1952.-Scheduled for publication this fall, the book contains information that has never been published in map form before, as well as much that has not been presented in map form for many years. Facts on 29 minerals most important in world trade are dealt with, along with interpretation of all data available on each mineral, discussion of the world's mineral economy from viewpoint of specific minerals related to mineral exploration, geographical distribution of world's consumption, and appraisal of the adequacy of world's mineral resources.

Jan 1, 1952

By George Jones

MACHINE mining on the pitch plays an important part in the produc-tion schedule at the Salem Hill Colliery of the Haddock Mining Co. This mine is just outside the city of Pottsville, in Schuylkill County, along the southern border of the Anthracite Region. The entrance to the mine is through a cross-measure tunnel 15 ft. above water level and running north 1500 ft. until it strikes the Rabbit Hole vein, where the machine mining is carried on. The main slope, dipping south, was sunk 1200 ft. in the Rabbit Hole vein with levels turned off at 300-ft. intervals. The vein is from 24 to 30 in. thick on a varying pitch of 20° to 40°. The overburden has differed from 50 to 466 ft., the most recent work having the maximum overburden. Immediately over the Rabbit Hole vein is a seam of soft sand slate from 1 to 4 ft. thick which presents a problem at times because it dis-integrates rapidly when exposed to the air. It will crack up and fall without any audible warning, therefore the workmen must always be on the alert, watching for loose slabs. The main top is sandstone, vary-ing in thickness from 8 to 20 ft. The bottom rock is similar to the top, but is finer grained and subject to a more complete disintegration. The vein has a 3 to 4-in. shelly band along the bottom, and all under-cutting has been done in this soft band.

Jan 1, 1935

By A. Lee Barrett

The Maintenance Committee of the Coal Division of the American Institute of Mining and Metallurgical Engineers is presenting with this report the first of a series of cost comparisons which it plans to present the Institute. The plan is to assemble maintenance cost on all equipment connected with mechanical operations at the face of coal mines, to arrange these costs by districts, to make comparisons between districts, and within districts. This particular report covers data with respect to mobile loading machines, including both "on-track" and "off-track" equipment. It is anticipated—in fact, considerable data have already been accumulated—that next year complete maintenance costs by districts can he presented for complete loading units, including the various classes and combinations of on-track and off-track equipment. Data have also been collected with respect to some phases of maintenance methods and certain recommendations of the committee are included dealing with maintenance problems. In the assembly of these data more than 120 questionnaires were sent to operating companies throughout the United States. At the time the report was written 33 questionnaires had been returned with completed information and an additional group of companies had written that the information requested was not at present available but that they hoped to have such information available in the not far distant future. The replies as

Jan 1, 1947

By Stanley J. LeFond, Neal Davis

Drilling an oil well or most other types of drilling or coring is no longer a simple and uncomplicated operation. Drilling today at depths which exceed 30,000 ft is hazardous and requires personnel with long and varied experience in drilling. It also requires extensive experience and knowledge in the use of materials which are added to the drilling fluid or "mud," more often than not materials utilizing an industrial mineral. The drilling fluid can vary from a simple mixture of water and "mud" to a very sophisticated, scientifically compounded drilling fluid. Industrial Minerals Used in Drilling Fluids Industrial minerals which are commonly used in oilwell drilling and completion are listed on [Table 1]. The most important minerals, determined by sales, are bentonite and barite. The other minerals listed are either used to achieve a specific purpose or are used regularly but in limited quantities. The main suppliers of drilling fluids internationally are Magcobar Div., Dresser Industries, Inc.; Baroid Div., National Lead Co.; IMC Drilling Mud Co., (a subsidiary of International Minerals and Chemicals Corp. and Halliburton Co.) ; and Milchem, a division of Baker Industries. Most of the industrial minerals are found in North America, with barite mines and processing plants located in Nevada, Arkansas, Missouri, and Arizona, and bentonite mines near Graybull, Wyo. Other mines, such as those in Nova Scotia, are capable of shipping to South America and to the European and Middle East countries. Most of the materials processed by any of the suppliers must conform to specifications set by the American Petroleum Institute (API) or the Oil Companies Material Organization (OCMA). These specifications provide for uniform physical and chemical properties of the materials to be sold on the open market.

Jan 1, 1975

By Charles P. Williams

BY PROFESSOR CHARLES P. WILLIAMS, ROLLA, MISSOURI. During the fall of the year 1873, attention was redirected to the occurrence of lead ores in Southwestern Arkansas (chiefly in Sevier County), and somewhat extensive explorations of the deposits have since been made in the hope of finding the ores sufficiently argentiferous to be profitably worked. How far the expectations have been realized I am not authentically advised, but samples of the galena ore, yielding 62.09 per cent. of lead, gave on assay at the rate of 15 3-10 ounces of silver to the ton of ore. This was the highest result obtained by myself, though I am informed that higher yields have been obtained by others. Among the samples of ores from this locality, forwarded to me in January last, was one specimen which I at once recognized as stibnite, and, on notification, other specimens of the same from Sevier County were forwarded me. The first specimen of the several received contained 11.51 per cent. of gangue, 57.62 per cent. antimony, 4.57 of bismuth, with small amounts of arsenic and iron. The latest result from a portion of another hand specimen I append in full, with duplicate estimations of the arsenic, bismuth, and gangue. The analyses were all conducted by Mr. C. R. Winters, under my direction, and in the case of those given below the ore mas separated as closely as possible from the gangue before analysis. The results are for the mineral freed from hygroscopic moisture, and are as follows: I. 11. Mean. Sulphur,.. 28.618 .. . 28.518 Antimony,.68.576 .. . 68.676 Arsenic,..6 47 .474 .497 Bismuth,..521 .498 .509 Iron,.......762 .. ..762 Gangue,..944 .948 .946 99.868 99.808 This result indicates that the ore is stibnite.

By A. Lee Barrett

The Maintenance Committee of the Coal Division of the American Institute of Mining and Metallurgical Engineers is presenting with this report the first of a series of cost comparisons which it plans to present the Institute. The plan is to assemble maintenance cost on all equipment connected with mechanical operations at the face of coal mines, to arrange these costs by districts, to make comparisons between districts, and within districts. This particular report covers data with respect to mobile loading machines, including both "on-track" and "off-track" equipment. It is anticipated—in fact, considerable data have already been accumulated—that next year complete maintenance costs by districts can he presented for complete loading units, including the various classes and combinations of on-track and off-track equipment. Data have also been collected with respect to some phases of maintenance methods and certain recommendations of the committee are included dealing with maintenance problems. In the assembly of these data more than 120 questionnaires were sent to operating companies throughout the United States. At the time the report was written 33 questionnaires had been returned with completed information and an additional group of companies had written that the information requested was not at present available but that they hoped to have such information available in the not far distant future. The replies as

Jan 1, 1947

By F. C. Newton

REFINERS of lead by the Parkes process have always been solicitous of recovering the zinc used in the desilverization, and justly so, as the loss in zinc constitutes one of the heavy costs in this method of refining. Part of this loss is due to the absorption of zinc by lead, and in the present state of knowledge is not recoverable as metallic zinc. The remainder of the zinc, which finds its way into the precious-metal-bearing crust, is recoverable and naturally engages the operators' most exacting attention. Careful elimination of the impurities in base bullion has enabled the refiner to produce a zinc crust better adapted to retorting, which reflects favorably in the zinc recovery; and to produce a richer crust, thereby lowering the zincking cost, as the increased efficiency of the zinc results in less of it being in circulation. It is obvious that if the ratio of concentration be increased, a lessening of the amount of crust formed will ensue, throwing less work on the retorts and diminishing the amount of retort metal sent to the cupels, thus making an actual money saving in all these operations. In the effort to obtain a rich crust, the metallurgist has increased the heat to a considerable degree, upon the assumption that at the higher temperature the zinc-silver alloy could be squeezed free from the adhering lead. A further possibility for improvement suggested itself in the freezing-point curve of Prof. H. C. Carpenter, upon zinc and silver. Study of this curve disclosed the existence of a definite chemical compound, . Zn3Ag2, with a freezing point of 665° C., a promising compound for practical application.

Jan 2, 1915

By John A. M. E. Church

AT the last meeting of the Institute, a discussion arose upon the question, " Is them pressure in coke ovens ?" and many of the members seemed to think that the superiority of the Belgian furnace might be due to the fact that it is a completely closed chamber, in which the gases given off by the coal are, or may be, at more than the atmospheric pressure. It seems to me that this position is untenable, and that an examination of one of these ovens in operation will show, not only that there is no excess of pressure in the coke chamber, but that the contrary is true, and a partial vacuum exists. The Belgian or François oven consists of a rectangular chamber closed at the ends by sliding doors, and furnished with flues in the side walls and floor. The new charge is introduced at a time when the furnace is so hot as to cause immediate and copious discharge of the volatile constituents of the coal. The gases pass downwards through the side flues giving out their heat to the walls and thus to the coal. Underneath the floor air is introduced and the gases burn, producing intense heat. Heat is also reflected from the arched roof upon the coal which is therefore heated from all sides. The especial advantage which this construction was designed to secure is that no air is admitted to the coke-chamber. All the heat is produced by the combustion of the uncokeable gases, and the yield ought to be a maximum. It is so in fact, allowing for the imperfections inseparable from furnace construction and management. Sometimes the yield is in excess of the percentage indicated by assay, showing that

Jan 1, 1873

I TOLD you above that you should save the melted material that you extracted by smelting the ore. In substance this is copper, lead, silver, and perhaps gold, but all are like substances mixed in one body without any distinction. Now if you wish to separate these and to reduce them to their pure qualities, it is necessary to proceed with each one according to its own methods. Now in this method of separating lead in order to extract the silver and gold from the copper, it is necessary to return to the smelting and to follow one of two methods.* The first is to smelt it again with the addition of lead or lead ore, and to make it all run through the channel into the large forehearth that was made in front of the blast furnace, and, as it cools off, proceed to remove layer by layer with the fork, as I told you before and as you did the first time, until the work lead is reached. Then you assay what you have extracted and see whether it contains silver. If you consider that it has enough per hundred to justify the expense, return it again to the smelting. Continue to do this until you have extracted all the unctuousness and the work lead still remains. If it contains little or no silver, you must be satisfied with your work; otherwise return it again to smelt, always accompanying it with lead or galena and do as you did the other times until it

Jan 1, 1942

By Albert H. Chester

DURING the summer of 1875 I visited some of the iron mines of Houghton County, Mich., and was quite interested to observe the progress made there within a. few years. Working in open pits is gradually giving place to underground work in most of the mines where this system is practicable. In some cases, as in the Lake Superior Mine, the body of ore is so irregular, and the deposit so liable at any time to be pinched out, or nearly so, that it has been found impractical, if not impossible, to lay out any plan for systematic underground work. But in many other mines the deposit is so regular in character, that the work can be laid out in shafts at regu¬lar intervals, and a series of 60 feet levels. The Michigammi Mine, opened in 1872, and first worked in 1873, is arranged on this plan, though some quarrying is still done. But the men are being put at overhead stoping as fast as it can be got ready for them, and before long it will all be worked in this way. The New York Mine is undergoing a similar change to the pillar system, and several others have either been changed, or it is about to be done. My principal object in visiting this region was to obtain samples from some of the important mines, so as to be able to answer the question : "What is the average percentage of iron in the Lake Superior ores?" Most iron furnaces work on mixtures of ore, so that it is impossible to tell, from their records, just the percentage in each one.

Jan 1, 1876

By A. R. Oltrogge

WE have just seen? that resistance is a characteristic of an electric circuit that makes it difficult for current to flow; also, that if, by the application of voltage, we cause a current to flow through a circuit having resistance, heat is generated. This is the principle utilized in the production of heat by electric power in the arc furnace. In order to fully appreciate the problems of the arc-furnace electric circuit, let us examine the characteristics of some of the more commonly used materials that offer resistance to a flow of current and thereby produce heat. Usually the resistance material is a metal or a metal alloy, such as the nichrome ribbon in an electric toaster or the tungsten filament of an ordinary light bulb. These are the materials whose resistance-remains relatively fixed and which therefore permit the flow of a definite amount of current for a given impressed voltage. If we want more current to flow, we must either decrease the resistance or increase the voltage that is causing the current to flow. Such a resistive material has what we call a positive volt-ampere characteristic, which means that in order to get more current we must apply more voltage, and in order to reduce the current we must reduce the voltage. Such a volt-ampere characteristic can be represented by a line plotted on a graph (line B, Fig I).

Jan 1, 1947