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By O. E. KEOUGH

AT the Tooele custom lead-zinc ore concentrator,' two sections, each having a daily capacity of 500 to 600 tons, are operated on slightly different types of ores with but little difference in flow sheet and reagents. The ores comprising the two general classes are the coarsely crystalline type, with low pyrite and sphalerite low in iron content, from the Park City district, and the more finely disseminated higher pyrite ores from Bingham, which are more difficult to treat by flotation. Laboratory testing determines with which general class a new ore will work better. The ores are crushed to minus 1 1/4-in. size at either the Utah Ore Sampling Company's plant at Murray, Utah, the Tooele smelter sampling plant, or the crushing plant at the concentrator. The ores for each section are mixed to maintain as nearly as possible uniform lead and zinc contents.

Jan 1, 1930

By AIME AIME

THE outstanding event of the past month has been the conference in Washington of the representatives of about seventy-five of the leading national, regional and local engineering and allied technical organizations." Editorial-July Journal-The American Society of Mechanical Engineers. ?Prominent engineers from all parts of the country, representing more than 75 engineering societies, with an aggregate membership of more than 125,000, participated in the organization.? Editorial-July Journal-American Institute of Mining and Metallurgical Engineers. ?Civil, mechanical, electrical, mining, heating, sanitary, chemical, agricultural, marine, refrigerating, radio, fire protection, automotive, industrial and military engineers, as well as some architects and geologists assembled at Washington, D. C. to consider the advisability of organizing a national federation capable of bringing the united efforts of the entire membership to a focus on any problem of mutual interest." American Architect, June 23, 1920. ?"the object sought places it above any engineering gathering ever held." Editorial-American Machinist, June 17, 1920. "The youngest. profession has voluntarily accepted its responsibility in human affairs and is now reaching forward to a career of essential service." "This is .unmistakably the meaning of the Organizing Conference " Editorial-Industrial Management, July; 1920.

Jan 1, 1920

By Charles W. Frey

SUCCESSFUL mining today means proper mechanization. Before any mine can begin production on a paying scale, some machinery must be installed. There must be pumps to remove water, fans and blowers to provide proper ventilation, elevators and hoists to raise materials, and a source of power to turn the countless wheels on which the world's mineral supply rolls from its earthhound source to the market. Only the prospector with his burro and the anthracite "bootlegger" continue to mine without mechanical aid, and with the recent years even these can be discounted, for the burro has given way to the Model T, and the "independent" coal miner must have a truck to haul his coal away. The few types of machinery mentioned above are but a beginning. The

Jan 1, 1938

Jan 1, 1908

By Claude Ferquson

MORE men are killed and injured in the metal mines of the United States from falls of rock and ore than from any other cause. Dan Harrington, of the U. S. Bureau of Mines, recently stated that "falls of men and material continue to take about 50 per cent of the lives annually lost in our mines (coal or metal) and this kind of accident is now and has been one of the most difficult to prevent." The fact that comparatively little has recently been written on this important subject for the benefit of the metal miner is the incentive for the present paper. Little will be said that will be new, but I hope to place fresh emphasis on certain well-known' principles' and to reiterate and stress previously stated rules so that the average experienced miner, as well as his buddy who may not be so experienced,' will sit up and take notice. It is not within the scope of this paper to discuss mining methods from the standpoint of safety and the prevention of accidents from falls of rock. It is up to the mine management to select the system of mining best suited to the character of the ore deposit and its wall conditions. This is something that the miner can do little about; although in many mines the management encourages the workmen to make suggestions that will improve existing

Jan 1, 1938

By G. A. Vissac

MOISTURE in coal must be considered as an impurity, just the same as ash, from the standpoint of utilization of the coal. Being incombustible, it reduces directly the heating value of the coal, and in addition absorbs heat for its evaporation. Its presence means useless expenditures in handling and transportation. In coke plants, extra moisture reduces capacity and may cause damage to brick work and equipment. Accordingly, the removal of extra moisture can be considered just as important as the removal of other impurities, such as ashes, in the modern coal preparation plant. Moisture, which can be removed by heating the coal up to a temperature of 100°C, may be retained in various forms: 1. As a film, on the surface of each coal particle, and in the interstices between particles, retained by capillary forces. 2. Or "occluded" inside the coal particles. This occluded moisture may be either free moisture (as in a sponge), or hygroscopic moisture which varies with atmospheric conditions, (also called "regain").

Jan 1, 1949

By Harvey S. Mudd

WHEN talking about Europe it is well to endeavor to keep politics and economics apart but they have become so intermingled in recent years that the discussion of one topic inevitably leads to the other. Economic influences formerly prevailed over politics but today national and international economies are governed by political forces. Commerce in raw materials, food, and manufactured products is now so restricted by governmental controls that the capacity of the world to produce and to consume, to exchange goods and to pay for them, cannot be gauged by the past or predicted by a multitude of experts. In prewar days there were some yardsticks but today there are none. Thus it is hazardous to make forecasts, for in all fields of human effort the world has been cast upon an uncharted sea.

Jan 1, 1947

By J. J. Forbes

Probably the newest thing in mining safety, or safety for mines, is the apparent dissatisfaction on the part of the mineral industries, as represented by both management and labor, and the general public of the Nation, with the safety record of the mining industry. This is reflected by published comments and papers in the technical press;1-8 in labor periodicals, 10 11 in popular journals and periodicals,12 13 and in the daily press; also by discussions of the Safety Committees sponsored by the National Safety Council, 9, 14-15 the American Mining Congress, 1, 16 the American Institute of Mining and Metallurgical Engineers, 2, 4 the Mine Inspectors' Institute of America,6,8,17,18 the Coal Mining Institute of America, 5, 19, the American Standards Association, and others.20,21

Jan 1, 1949

By C. E. McWhorter

IN underground mining recent trends toward mining large tonnages of low-grade ore have created, among other things, a need for cheaper and more flexible ore transport. A relatively new development has been the adaptation of shaker conveyors to meet this need. Although widely used in coal mining, only in the last few years have shaker conveyors been used in underground metal mining. The equipment consists of a driving engine, either electric or air powered, upon which is mounted a drive trough supported in ball-bearing frames. The trough line, or conveying medium, is made up of a number of sections, each section connected to another, usually with bolts. The length of each trough section is controlled by the length that can best be handled underground, but is usually from 9 to 13 ft over-all. The length of a complete conveyor line is determined by the character and weight of material to be handled as well as by the size of the ore body. Trough lines vary in lengths from 100 to 300 ft and the trough has a cross-section area of 127 sq in., and is 22 in. wide by 6 ½ in. deep.

Jan 1, 1948

By Augustus Locke

Jan 1, 1923

By Augustus Locke

Jan 1, 1923

G. A. Moore—The tin-fusion method has been a very favorable possibility for many years. The authors apparently have settled the question that delayed the method for a long time by showing that no hydrogen is absorbed in the tin. This, of course, is very important. I want to make a few remarks concerning the absolute accuracy of analysis, which must be the final basis for deciding among the various methods. From the figures in the paper, there seems to be some re-maining slight discrepancy on the actual amount of hydrogen present in various samples which may be presumed essentially identical. (This is of the order of the precision of individual analyses but appears in averaged results.) From the analyst's viewpoint, the tally of hydrogen content can be regarded as occurring in three portions. First is a large portion which comes off easily and automatically during sample storage and later on heating in the apparatus. This is fairly easily analyzed. Second is an item which may be either positive or negative in the tally sheet. In warm or hot evolution, this is a portion which, in practice, can never be re-

Jan 1, 1951

By Kirtley F. Mather

FROM almost every point of view, petroleum was "strategic mineral number one" during the World War that ended in 1945. Even the spectacular advent of the atomic bomb in the final days of the conflict did not displace it from its position of prime importance, although within a few years uranium will almost certainly be the "number one" material in the minds of military strategists, if it is not even now in that position. But both as fuel and as raw material for chemical industries, petroleum will hold the center of the stage for many years to come. Hardly any other substance illustrates so fully the manner in which science and technology may be combined to achieve the utmost success in contributing to human efficiency and comfort. Fundamental to any understanding of the problems implied by my topic

Jan 1, 1948

By AIME AIME

AN unusually interesting meeting devoted to the discussion of the ways and means of improving coal mining practice, through the larger use of machinery underground, was held in the Auditorium of the Engineering Societies Building on March 11. The meeting was organized by the Materials Handling Division of the A. S. M. E. and held under the auspices of the Metropolitan Section of that Society and the National Coal Association. The New York Section of the A. I. M. E., which had been invited to participate, found itself unable to do so formally because of a conflicting date for its March meeting but informally did its part to aasure the success of the meeting. As a result of the discussion at and preceding the meeting, the National Coal Association, through Walter Barnum, chairman of its research committee, has asked the A. S. M. E. and A. I. M. E. to join the Association in a study of the present problems of the bituminous coal industry. Messrs. Harry L. Gandy, Calvin W. Rice and H. Foster Bain have been selected to act as a committee which shall develop plans for a joint program.

Jan 1, 1926

By Ellsworth Daggett

THE system of pitwork used with the Cornish pumping engine, and which, for want of a better name, we may call the Cornish system of pitwork, consists essentially of a series of plunger-pumps, situated one below the other, in a shaft or incline, the plungers being operated by a rod called the pitman or pump-rod, which must, therefore, extend from the motor at the surface to the lowest pump. The subject will be best understood by reference to Fig. 1, in which k may be taken as typical of the ordinary plunger-pump, in which S is the suction pipe, u, the lower valve situated in the H piece T; v, the upper valve situated in the valve-box O; I, the mounting-pipe or column through which the water is carried to the surface; L, the plunger-barrel, and P, the plunger working through the stuffing-box, and actuated by the branch rod r, which is attached to the main pump-rod, R. The action of the pump is as follows : On the ascent of the plunger, acting now by suction, the water flows from the reservoir through the valve u, into the barrel, L. On the descent of the plunger, the water is forced up through the valve, v, which acts merely as a check valve, into the pipe, I, through which it is, at each successive down-stroke of the plunger, forced upward until it reaches the next reservoir, from which it is taken by another similar pump, and so on until it reaches the surface or drain-tunnel. The pump is obviously only single-acting, i. e., it acts only during one-half of its entire stroke. The weight of water raised during the up-stroke of the plunger is equal to the weight of a column of water whose base is the area of the plunger and whose height is the mean distance between the plunger-face and the surface of water in the lower reservoir, a distance not usually exceeding 12 or 15 feet, and which obviously cannot under the most favorable circumstances, exceed 25 or 30 feet. The water forced up during the down-stroke is equal to the weight of a column of water whose base equals the area of the plunger and whose height equals the length of the mounting column above the mean position of the plunger-face, say from 150 to 300 feet. Almost all of the useful work, therefore, is done on the de-

Jan 1, 1879

By D. W. Brunton

Discussion of the paper of D. W. Brunton, presented at the Spokane meeting, September, 1909, and published in Bulletin No. 33, September, 1909, pp. 837 to 855. WILLIAM' KENT, New York, N. Y.:-The Institute may congratulate itself on the opportunity of reading the splendid address of President Brunton. It is au admirable summary of the progress that has been made in the mining and metallurgical arts in recent years. The paper rightly give's the chief credit for this progress to the aid which has been rendered to these arts by the advances in mechanics, chemistry, and electricity. It is notable that most of the headings in Mr. Brunton's address refer to the work of the mechanical engineer, the electrical engineer, and the chemist, rather than to that of the specialist in mining-operations. It seems that. the most successful mining engineer of the present day is the one who makes the most intelligent application of the inventions and designs of engineers and others who are not directly engaged in mining. A tabulation' of the headings of the address, grouped as below, shows this most clearly. Work of the Mechanical Engineer-Rock-drills, hoisting-machinery, tramming, pumping, ventilation, dredging, sampling, concentration, briquetting, fume-recovery. Work of the Electrical Engineer-Electric machinery for hoisting, pumping, tramming, lighting and signaling, electric . transmission, electric smelting. Work of the Chemist and Metallurgist-Explosives, chlorination, cyanidation, roasting, lead-smelting, and copper-smelting. Work of the Geologist-Economic geology. Work of the Mining Engineer-Mine-mapping, surface-mining, timbering, tunneling; and planning and supervision of the work in general. The mining engineer of the present day, who is in responsible charge of a large plant, finds his chief work not in doing

Jan 1, 1910

By Herty, C. H.

Present-day interest in the question of "dirty steel" has arisen primarily from the increasingly rigid specifications on various grades of steel and from the growing conviction that non-metallic inclusions are the source of many of the difficulties in meeting these specifications. The importance of inclusions has unquestionably been over-emphasized in many cases, but on the other hand many unpublished instances could be recorded where all evidence pointed to inclusions as the primary cause for the failure of steel in rolling or in service. The solution of the problem of dirty steel is not a matter of a few years. There are almost numberless types of inclusions. They segregate in steel ingots in an entirely different manner from other impurities, and, at best, only a start has been made in developing correct analytical methods for their determination. Most of the writers in the field have expressed opinions rather than given facts, and so many variables enter into the manufacture of steel that a study of plant conditions is difficult unless definite facts on certain phases of the inclusion problem are available. This statement is not intended to convey the idea that little work has been done on this problem. On the other hand, the number of investigations has been large, but in most cases too many variables have been present to allow definite conclusions to be drawn. In the body of the text, reference to previous investigations is made at suitable points. Rather than burden the reader with a lengthy review of the literature on the general subject of inclusions, reference to the particular works pertinent to the subject matter of the bulletin has been discussed. Three excellent bibliographies b on the subject have been lately published: one by the Committee on

Jan 1, 1957

By R. M. Raymond

RECENTLY one of the Welsh coal companies, which has an excellent plant of up-to-date ma-chinery both on the surface and underground, operated under modern methods, sent one of its engi-neers to the United States to study actual operations in the mines. He visited several of the most important and best conducted collieries, went back, and reported that the greatest difference between operations in England and in the United States was. the closer con-tact between management and workmen. By manage-ment he meant management all the way through; close cooperation between office management, superintend-ents, foremen, shift-bosses, etc., and the workmen. A visit to some of the coal mines in that country by the writer made this fact rather impressive. The feel-ing on this side of the water that the methods in use in the coal mines in England are not up-to-date was found in many cases to be quite erroneous. Many mines, particularly those with very thin beds, in which profitable operations are doubtful under the best con-ditions, have necessarily had to adhere to old methods instead of making mechanical improvements. The Powell-Duffryn mines, in the center of the South Wales district, are certainly operating successfully, and have planned their business excellently. Sufficient areas of contiguous land have been leased for extended opera-tions. Mine plants are laid out in the valley, for work-ings on both sides, on a reasonable tonnage of 1500 to 3000 tons to each operation. The beds are from 30 to 48 in. thickness, and a 3-ft. seam is considered an ex-cellent thickness of coal; in fact, the miners prefer to work on the thinner beds rather than the thick ones, where they consider it more difficult to control the backs. This company is making use of its fine coal for produc-ing electric power, which is distributed to its own operations, and for use in the communities adjoining. For this purpose methods of cleaning the fine coal are being put into use. Compressed air is generated at the central power plant and is transmitted over long dis-tances to various mines in each valley. A byproduct coke plant uses more of the fine coal and gives further returns from non-commercial coal. The long-wall system applied in sections of limited size is popular in working the small seams, and me-chanical cutting is used, also handling either by shaking chutes or belt conveyors, or a combination of both. In some mines mechanical cutting is not necessary. The backs are so handled that in the softer or somewhat crushed seams hand cutting can be carried on effec-tively.

Jan 10, 1927

By Frederick M. Becket

AFTER all the chronology that has been given, what is the present status of chromium steels? For the purpose of this discussion the different types of chromium steels can be divided into three classifications-those containing relatively low , percentages of chromium, say 5 per cent or less; the medium-chromium steels containing up to about 18 or 19 per cent chromium; and the steels containing still higher percentages of chromium, and some of the special alloys. Chromium has some unique effects in steel, so it is well to make a few generalizations. The affinity of chromium for carbon is great and the metal is unique in the manger in which it supplements and enhances the effects of carbon. Chromium retards -considerably the thermal transformations on cooling and exerts an opposing influence both on the absorption and precipitation of the carbides in steel. These statements make it easy to understand the fact that chromium .steels are capable of producing a hardened product at a much slower rate of cooling than is, true of plain carbon steel, and that chromium carbide or -the mixed carbides of iron and chromium do not contribute to brittleness to as great a degree as does iron carbide.

Jan 1, 1929

By John D. Sullivan

A DISCUSSION of the developments of the past decade in the field of refractories, and the effect of these developments on the performance and life of open-hearth furnaces, is perhaps best introduced by reference to Fig. 1. This shows the most important types of refractories doing into various parts of the furnace, together with their cost, and remarks on their use. It has been estimated that half of the refractory makers market comes from the iron and steel industry, and something like one-third of all refractory brick used finds its way into open-hearth furnaces. To melt steel, a furnace capable of withstanding temperatures close to 3000 deg. F. is required. The furnace is assembled of various refractory materials selected by experience and economic considerations. Furnace structures today, from a refractory standpoint, are considerably different from a quarter century ago. Furnace operators, interested in the performance of refractories, care little how they are made or where they come from so long as they give reasonable service. But, the entire history of the refractory is important and technical knowledge of the ceramic materials used in making the refractory is necessary to the manufacturers, so that the proper article gets into the hands of the ultimate consumer.

Jan 1, 1936