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By Philip B. Bucky

[CONTENTS t. How Does One Determine WhetherPAGE an ore Body Will Block-cave?R. W. Hughes13 Sherman R. Burdick 13 PAGER. T. Gallagher 14 Mark A. Smith 2 C. F. B. Price, Jr.14 Harry A. Leidich2Benjamin F. Tillson 14 McHenry Mosier2C. F. Jackson14,17 R. W. Hughes2R. Taborelli15 Sherman R. Burdick3Frank A. Ayer16 R. T. Gallagher 3Philip B. Bucky16 Benjamin F. Tillson 3Rollin Farminr6 Lucien Eaton 3J. L. G. Weysser15, 0,17 C. F. Jackson 3George S. Rice17 Philip B. Bucky32. How Does One Determine the Block4. What Determines the Procedure in Dimensions and the DevelopmentRemoving Caved Ore? Work Necessary to Make an OreHarry A. Leidich17 Body Cave?McHenry Mosier17,21 Mark A. Smith 5,7,() R. W. Hughes17 Harry A. Leidich6Sherman R. Burdick 18 McHenry Mosier6,7,12 R. T. Gallagher 18 R. W. Hughes6Mark A. Smith I8 Sherman R. Burdick 7Philip B. Bucky20, 21, 23 R. T. Gallagher 7C. F. B. Price, Jr20 Benjamin F. Tillson 7,11R. H. Bennett21 L. E. Young7C. F. Jackson 21, 23 Robert D. Hoffman8, 1 2Gerald Sherman 3 . 21 Gerald Sherman8Tell Ertl21 Philip B. Bucky10, 11, 12G. K. Foster 23 R. S. McClellan 12C. H. Shoemaker23 Tell Ertl 12 3. How Do the Forces Act and What Are5. What Are the Criteria for Determining the Stresses Developed in a Blockthe Efficiency of a Block-caving That Cause It to Block-cave?Operation? Mark A. Smith 12, ISHarry A. Leidich23 Harry A. Leidich13McHenry Mosier24 McHenry Mosier13R. W. Hughes24 Sherman R. Burdick 24 R. T. Gallagher 24]

Jan 1, 1942

By Frank Armstrong

ALL the mining machinery of the Penn Iron Mining Co. has been operated by electric power for several years and when another shovel for stockpile loading was required the advantages of an electric shovel were naturally considered. After considerable study, serious objections suggested themselves the use of a shovel operated directly by electrical apparatus by reason of the complicated control, severe service on the motors FIG. 1.-ELECTRO-HYDRAULIC SHOVEL FIG:. 2-THE SHOVEL AS IT WAS OPERATED CINDER CONSTRUCTION. THE FIRST YEAR. and the heavy surges of current required from the line. It was finally decided to construct an electro-hydraulic shovel using water under pressure to perform all the necessary operations except that of propelling, for which a separate motor was best suited. A car body with boom, dipper handle and dipper of late design, but without any of the steam machinery, was purchased. A motor-driven centrifugal pump, a pressure tank, an air tank, a small air compressor and water cylinders with plungers, pistons and valves, were installed in place of the; steam equipment. Fig. 1 shows this shovel under construction and Fig. 2 shows it as it was operated during the first year, the summer of 1914. The large tank at the back of the car, in Fig. 1, carried air under

Jan 2, 1916

By K. Leutwyler, H. L. Bigelow

Jan 1, 1966

By AIME

IN the parlance of Hollywood, it was a super-colossal meeting. In the more restrained language of engineers, the Institute's 75th Anniversary Celebration attracted the largest crowd ever; was the longest Annual Meeting ever held, occupying a full week; had more important papers, more important people, more of an international flavor, and more glamour than ever before. And in the minds of those who came to the big city from the wide open spaces, one other record should be mentioned: for those not on an expense account, it was the most expensive affair ever staged by the Institute! To state the attendance down to the last digit for a meeting such as this is impossible. The total names registered on cards, plus those who attended the Annual Banquet but were not otherwise registered, came to 3149. But a few were registered twice, and probably a still larger few did not register at all, but just dropped in for a session or two in which they were interested. It would appear that 3200 would be about as close an estimate of attendance as could be made, and that is some 300 more than came to the biggest Annual Meeting of the past-in 1944. A considerable number of members brought their wives, but most were delegates at large.

Jan 1, 1947

By F. A. Seward

A1though the expanding Eltran1 configuration has been used in induced polarization exploration for several years, there has been little application of this method to straight resistivity problems. A comparison of results of resistivity exploration by this technique versus those obtained from Wenner configuration surveys reveals a number of advantages in interpretative resolution as well as in field operation. The application of electrical resistivity to ground-water exploration is well known.= In the past a major portion of this work has been accomplished by use of one or more variations of a technique employing the Wenner3 electrode configuration. With the introduction of the frequency domain technique of induced polarization measurements, used primarily in the exploration for disseminated sulfide deposits, there arose the need for an electrode configuration by which potentials could be measured externally to the current electrode spread in order to minimize coupling between current sending and potential receiving circuits. It was also deemed desirable that the configuration would provide information laterally along profile as well as with depth. To reach these objectives the expanding dipole-dipole configuration (which probably first was used in the electrical transient method of exploration and from which the name 'Eltran' was derived) has been adapted to induced polarization exploration. The author has successfully applied the same techniques

Jan 1, 1963

By C. S. Smith

It is the policy of The Metallurgical Society to provide, in the TRANSACTIONS OF THE METALLURGICAL SOCIETY OF AIME, a prompt and accurate medium for publication of reports of significant new research in both the scientific and engineering aspects of metallurgy. Papers submitted to the Society are judged by competent reviewers according to established criteria for technical merit, accuracy, originality, and presentation. STAFF: Editor, Dr. Gerhard Derge; Editorial Assistant, M. A. Redmyrski; Staff Coordinator, James J. Burke. THE METALLURGICAL SOCIETY: W. R. Hibbard, Jr., President; J. C. Kinnear, Jr., Post-President; John Chipman, Vice President; T. D. Jones, Treasurer; R. W. Shearman, Secretory. PUBLICATIONS COMMITTEE OF THE METALLURGICAL SOCIETY: A. W. Thornton, Chairman- Dennis Carney John Chipman J. C. Fulton J. H. Hollomon H. H. Kellogg, A. E. Lee, R. Moddin, J. D. sullivan, and D.' Swan. Review and selection of manuscripts is under the supervision of the following Publications Committees: Extractive Metallurgy Division: T. B. King, Chairman; S. J. Dickenson, R. P. Hermsdorf, R. Schuhmann, Jr., and P. T. Stroup. lnstitute of Metals DM lion: Robert Maddin, Chairman. F. Lincoln Vogel, Jr.. Vice chairman. W. A. Backofen R. W. Boliuffi J. H. Bechtold' M. B. Bever R: S. Busk C 6. Goetzel poul Gordon C. D. Grobom, Jr., Robert F. Hehe-mann R. I. Joffee F. i. Joumot Jr. lrvin R. Kromer, A. J. Leno. Horold Morgolfn, C. J. McHargue, Russell A. Meussner, J. B. Newkirk, H. W. Paxton, G. E. Pellissier, I. S. Servi, Alon U. Seybolt, A. J. Shaler, and Jack Washburn. Iron and Steel Division: J. C. Fulton, Chairman. T. B. King, F. C. Laogenberg, W. O. Philbrook, and T. 0. Winkler. Publishod bimonthl by the American Institute of Mining Metollurgicol and Petroleum Engineers Inc., 29 West 39th Street, New York 16, N. Y. Telephone: PEonylvanie 6-9220. Subscription $20 par yew for non-AIME members in United States and North, South and Control Americo $25 foreign; $5 for AIME members. Single copies, $4.00, single copios foreign $5,00. The AIME is 1958 by the Amarican mode or opinion axpressed in it* publications ... Copyright by the Amarican lnstitute of Mining, MataIlurgicol, and Petrolum Engineers, Inc,. . . Reg. istered cable address AIME New Yark ... Indexed in Engineering Inderx, Industrial Arts ...Index and Chemicol Number5. Absrtracis . . . Second class postage paid at New York,Indor. N. Y., Industrialond Ann Arbor, Mich.

Jan 1, 1959

By EDWARAD A. SIVEDENBORMG

REPORTS have been made at different times on the progress of water encroachment in the Frontier sands in the Salt. Creek oil field, Natrona county, Wyoming. All previous reports have, -however, been largely based on the position of water in the sands as determined by various physical tests. Subsequent information has been secured through a preliminary investigation of the porosity, grain size and degree of saturation of the Frontier sands. Also, a closer differentiation has been made between the waters encountered incident to the production of oil by means of chemical analysis. In view of the more recent developments there has been a need of a water encroachment map of the first Wall Creek based on a field survey and additional information acquired since the water encroachment map of the sand of 1926, by J. S. Ross and E. W. Henderson, petroleum engineers of the U. S. Geological Survey. The present report is confined to a study of the first Wall Creek sand and was written in connection with the preparation of the map, showing water encroachment in this sand. The first Wall Creek sand was the discovery sand in the field, the first well having been drilled in 1908. Its thickness averages 120 ft. and, varies between 90 and 160 ft. The sand is in the Colorado group of the Upper Cretaceous series and is further considered as a part of the Frontier formation found in other parts of Wyoming.

Jan 1, 1930

By W. H. Morris

I have been requested to present a paper on the slag from the basic Bessemer process, as prepared for fertilizing. Since Professor W. B. Phillips presented at the Birmingham meeting, in May, 1888, an able paper* on this subject, as it had been developed up to that time, there is little for me to add. Perhaps later practice may be best expressed by the homely proverb, " The proof of the pudding is in the eating." As the Pottstown Iron Company is the only concern manufacturing basic Bessemer slag in this country, the writer's personal experience in the use of it may be interesting. Our slag averages: P2O5, 21.37; SiO2,, 5.10; MgO, 5.90; Al2O3, 4.01; MnO, 5.56 ; FeO, 12.00; Na2O and K2O, 0.80; CaO, 45.26; total, 100.00. This gives over 76 per cent. of phosphoric acid and lime. In using this material for several years past on my lawn and garden, I have found it better than anything else I have ever tried ; and I am sure that any of you who had seen my green grass last month (January), wherever the ground was bare from snow, as bright as in early fall, would be forced to acknowledge the advantages of this soil-enricher. The grass on my private lawn, and around the company's office, is green the whole winter; and we have raised very good sod, by the use of this phosphate, where, without it, we were unable to get the grass to grow either from seed or by repeatedly sodding. The same statement applies to garden-truck; when the soil was first broken up, a good crop of vegetables was easily raised. My own gardener has had several premiums from Philadelphia seedsmen (notably, last year, the first premium for sugarcorn raised in the first part of July, being the first sample sent them). Our method of applying this material is to grind the slag very finely, so that at least 60 per cent. of it will go through a 150-mesh screen (i.e., say, 22,500 meshes to the square inch), and 90 per cent. through a 100-mesh screen (i.e., 10,000 meshes to the square inch). This fine grinding seems to be the main condition of success.

Jan 1, 1893

By AIME AIME

CONVENTION plans for the A.I.M.E. Regional Meeting to be held on the Minnesota Iron Range Aug. 12 to 1.5 are being completed to give the visiting member?s from all parts of the country a wide variety of technical and recreational features. High spots of the social events are the official dinner, dance, luncheon and golf: and of course, special provision is being, made for the entertainment of visiting ladies. The technical sessions will fit in with scheduled trips to view all phases of mining, beneficiation and transportation of iron ore. Men from the West and Southwest will find much of interest in the detail of the mining operations. A trip to the steel plant of the

Jan 1, 1941

By ALBERT F. J. BOARDEAUX

(Canal Zone Meeting, November. 191(j.) I. GENERAL INTRODUCTION. 1. Historical. ALLUVIAL gold was first discovered in Guiana in 1852, in the sands of the Arataye river; by Paulino, a Brazilian convict. During the following years, gold was found also in the rivers Orapu, Cirubé, etc. In 1873 the famous placers of the Sinnamary system were opened: Saint-Elie, Dieu-Merci, Adieu-Tat, and Couriége. This group of mines has produced nearly $10,000,000, according to official records, not including the gold that escaped the taxes. The discoverer was a mulatto named Vitalo. Except in a few rich spots, the gold was rather evenly distributed along the creeks. In one instance, gold was found in the red dirt from the slope of a hill, which, after transport to the creek, gave an amount of 150 kilograms. The placers of the Mana system, Enfin, Elysée, Pas-Trop-Tot, date from 1878, and their production has been about $5,000,000. In 1888, the Awa placers, along the boundary between the French and Dutch Guianas, on the Maroni and its tributaries, were discovered. They have yielded $12,000,000. The only industrial company,, the Dutch Guiana French Mining Co., produced in 15 years about 2,500 kg. of gold, worth $1,500,000. From 1893 dates the famous Carsewene discovery, in territory then in dispute between France and Brazil. A settlement was made recently in favor of Brazil, by arbitration of the Switzerland State Council. Carsewene is said to have pro-duced about $18,000,000 in six years (1894-1900), but not even one-fourth of the production went through French Guiana and

Nov 1, 1910

By T. Egleston

The materials containing copper which are refined in the United Statrs, are, for the most part, the natiye noppers of Lake Superior. IJntil quite recently but little pig copper Was made for sale, and that came principally from the pure sulphorous ores of New England and the Sonth, and was generally sdd to reSneries not far from the ore filrnaceu. A stnall aiuoiint found its way into the'niarket which was produced either as the by-product of the treatment of gold and silver ores, or as the result of the treatment of impure copper ores; but both these grades, on account of the impurities they contained, were loolced on with stlspicion, and were not sought for. A11 the grtlGis of pig coppcr are sold by the unit of oopper contents, a great redtiction being made in the price when impurities are present. There are at the present time only three works which treat native copper, the two of the Detroit and Lake Superior copper Company, and the works of C:G. Hussey & Co., in Pittsburgh. There are a few works ivhich smelt sulphuroris ores and refine their pig; bo sides these t1le1-e arc a few siuall works where gig copper is refined uuly. Some of these purcIlase blscir copper, refine scrap, or simply refine such grades of ingot copper as are found in the market, but nlostly that from Lake Superior, for the purpose of getting it into swh shapes that can be handled cpmtriercially to advantage, such as in making large plates or high grades of wire fir electrical purposes. A nomher of such works are situated in the Xaugaturk Vatley aud elsewhcre in New England. The recent discoveryof vnlt~sblc ores in Ariarona makm it probable that within a few year8 the refining of capper In the United States will make great develupments. Up to the time of the discovery of the mines on Lake Superior, only a very small quantity of native copper had ever been foond, not sufficient to justify the erection of worlrs fbr its special treatment. It had, besides, never been found in very large maweq so that the discovery of greabblocks of it presented serious difficulties, not oolp in mining it,-I- but in bringing it into a merchantable condit'ion. It seemed a very simple process to melt these large maws,

Jan 1, 1881

By Mehmet Guney

At the Armatcuk mine in Turkey, various modifications of sublevel methods have been tried during the last decade in an effort to eliminate gob fires, dangers from roof falls, and surface subsidence, and also to increase extraction efficiency. From the experience thus gained, it was decided that the most likely system to give maximum benefits, considering the existing geological conditions and coa1-seam characteristics, was hydraulic stowing. This paper examines trends in the working techniques of hydraulic stowing and discusses the favorable results and technical problems that the method produced at Armutcuk. The Armutcuk mine, a subsidiary of Eregli Coal Mines (EKI), produces 1300 tons of run-of-mine coal daily from thick (about 10-90 ft) and highly dipping (about 50-90°) coal seams. The coal is highly volatile with good coking properties that make it highly suitable for industrial use. Most of this coal is used in the iron and steel industry at Eregli on the Black Sea coast. Complete recovery of the coal is of vital importance to industrial development and progress. Initial coal extraction was carried out by means of a sublevel mining system modified to accommodate local geological conditions and coal seam characteristics. This method is similar to that employed in metalliferous mines. Several problems arose from the application of the method, one of them being the prevalence of gob fires which caused periodic shutdowns in some sections. To achieve maximum coal extraction with minimum dilution, to eliminate gob fires and surface subsidence, and to reduce fatal accident rates, a decision was taken to change from this method to a hydraulic stowing system. The pres- ence of large deposits of conglomerate and sandstone on the surface contributed to the decision to employ this new method. Although hydraulic stowing practices have been carried out in America and Germany, Upper Silesia may, so far as coal is concerned, be considered the birthplace of the method. Here the process was adapted to thick coal seams on a large scale to reduce dangers from gob fires and damage from surface subsidence. Today, the mining system is not only widely used in the coal mines of France, the Saar, India and Poland, but has also been successfully applied to the iron ore and potassium salt mines in Russia and Germany. LOCATION AND HISTORY The Kandilli-Armutcuk coal field, the most western outcrop of the North Anatolian coal basin, extends for five miles along the Black Sea coast (Fig. 1). The Armutcuk Mine is situated on the southern boundary of the coal field about 40 miles from Zonguldak and about 12 miles from Eregli. The history of coal mining in the North Anatolian coal basin goes back more than a century. Mining commenced on a small scale in the Kandilli-Armutcuk coal field in the late 1880's, and from this time until nationalization in 1940 the mines were operated by private Turkish and foreign interests. In 1940, Eregli Coal Mines was established to takeover the management of these enterprises. The Armutcuk Mine was developed for the first time in the mid-1940's. Since then it has been in continuous production and it now produces an annual 440,000-ton run-of-mine output from which 320.000 tons of salable coal is obtained. MINE GEOLOGY The carboniferous inlier of the Kandilli-Armutcuk coal field crops out over an area about three miles long and one mile wide. The major part of the inlier consists of the Namurian formation with only a relatively small area of Westfalian-A visible on the surface (Fig. 2). The Namurian formation, which has no exploitable coal seams in the Armutcuk Mine, consists mostly of arkose sandstones and black shales often having

Jan 1, 1969

Albin. B . R Billings. Mont . '28 Amnter . Nathan L 26 Broad St.. New York . N . Y . '28 Bache . Jules S 42 Broadway. New York. N . Y . '28 Borrett . C . P . 5338 Harper Ave .. Chicago. I11 '28 Baum . Frank G. . Cons . Hydro-Electric Engr Camel'. Shasta Co. . Cal. '23 Baylean, William S Russ Bldg .. San Francisco. Cal . '28 Bean, Louis H .. V.P.. Dwight P . Robinson & Co.. lnc 126 E . 46th St New York. N . Y . '28 Beatty . Roes J . 1106 First National Bank' Bldg .. Chicago . Ill . '28 Benwell . Oswald F . 110 Gilpin St .. Denver. 1310 . '28 Beymer. Albert 9.. V.P .. Keystone. National Bank Pittsburgh. Pa . '28

Jan 1, 1929

By L. C. Graton, Joseph Murdoch

I. Introduction......................... 26 1. The Relations of Scale in Geologic Work........ 26 2. General Characteristics of Copper Sulphide Ores..... 29 3. Scope of Present Study................. 31 11. Description of the Important Minerals............ 36 1. Pyrite....................... 36 2. Pyrrhotite....................... 41 3. Chalcopyrite...................... 41 4. Bornite........................ 40 5. Covellite....................... 50 6. Chalcocite....................... 52 7. Enargite...................... 59 8. Tetrahedrite and Tennantite.............. 61 III. Conclusions.......................... 62 I. Introduction. The Relations of Scale in Geologic Work. Many features of human accomplishment rest upon the possibility of representing natural objects on a scale of different magnitude from the actual one. Most drawings, for example, are of very different scale from that of the object depicted, and indeed are useful mainly 011 this account. More important than the question of mere convenience, however, is that of meeting the physical limitations of vision.' Thus, a mural

Jan 1, 1914

Discussion of the paper of R. J. COLONY, presented at the New York Meeting, February, 1921, and issued With MINING AND METALLURGY No. 169, January, 1921. R. J. COLONY (author's reply to discussion).-The work of Sosman and Merwin on the system lime-ferric oxide, mentioned by Mr. Rankin, was not overlooked. When studying portland cements and portland-cement clinkers petrographically, however, the lime-iron compound was difficult to correlate with the very definite dicalcium ferrite described by those investigators, which possesses such well-defined optical properties. In portland cements, the calcium ferrite (or ferrate?) is an indefinite, fuzzy, and generally amorphous, or apparently amorphous substance that is distributed interstitially with respect to the other grains, from which it was very difficult to derive any satisfactory results. For this reason, the writer, tentatively, chose to regard it as related to the aluminate, and assigned to it the composition 3CaO.Fe203, which may be incorrect, however, as Mr. Rankin suggests.

Jan 8, 1921

By Frances H. Clark

DEVELOPMENTS in powder metallurgy have been disappointing in 1943. If any new part has gone into large-scale production, knowledge of it has been restricted by considerations of national security. Nor have any outstanding papers appeared to advance the theory of the subject during this period.

Jan 1, 1944

THE first session was held in the small hall of the Academy of Music, on Tuesday evening, February 18th, 1879. The proceedings were opened by the reading, by President Eckley B. Coxe, of the following Address : SECONDARY TECHNICAL EDUCATION. Technical education is a subject to which both the American Institute of Mining Engineers and the American Society of Civil Engineers have of late years given much attention, and deservedly so. We all remember the admirable address of our former President, Mr. Holley, at the Washington meeting, upon this subject, and the very interesting reunion of the two societies in Philadelphia for its discussion. The problem to the solution of which the meeting devoted its attention was, "Shall the practical education of the engineer in the mine, in the rolling-mill, in the workshop, or in the field, precede, be contemporaneous with, or follow his theoretical studies in the technical school ?" I do not propose to add anything to what was so admirably said by so many of our leading engineers on that occasion ; but I shall ask your attention to another question in technical education, which seems to me equally worthy of our consideration, and which, I am sorry to say, has as yet attracted but little attention in this country. It is, "Shall the apprentices (I call them so for the want of a better general name), who are growing up and learning their trades in and around our mines and works, and from whose ranks the master mechanics and foremen of the future must be taken-shall they be provided with some means of obtaining as much theoretical training as may be necessary to enable them properly to understand the various processes and operations that they may be called upon to superintend, and not be obliged to pick up, as best they may, here a little and there a little truth mingled with much error?" In the former case, those who have the ability and industry to avail themselves of the advantages that should be offered to them would fit themselves to become real foremen, men who would understand and appreciate the true engineer and his methods. Of late years the young men of this country who have wished to enter our profession have had great facilities offered to them for so doing ; there have been undoubtedly great improvements in the methods of instruction; and although I am very far from imagining that no further progress can be made, or is demanded, yet I feel sure that

Jan 1, 1879

By K. G. Gorling, S. J. Wallden, N. B. Lindvall

It is the policy of The Metollurgical Society to provide, in the TRANSACTIONS OF THE METALLURGICAL SOCIETY OF AIME, a prompt and accurate medium for publication of reports of significant new research in both the scientific and engineering aspects of metallurgy. Papers submitted to the Society are judged by competent reviewers according to established criteria for technical merit, accuracy, originality, and presentation. STAFF: Editorial Director, Rixford A. Beals; Associate Editor, James J. Burke; Assistants, L. Capria and R. K. Larkin. PUBLICATIONS COMMITTEE OF THE METALLURGICAL SOCIETY: A. W. Thornton, Choirmon; Dennis Carney, John Chipman, J. C. Fulton, J. H. Hollomon, H. tl. Kellogg, A. E. Lee, R. Maddin, J. D. Sullivan, and O. Swan. Review and selection of manuscripts is under the supervision of the following Publications Committees: Extractive Metallurgy Division T. B. King. Cha~rmon; S. J. Dickenson, R. P. Hermsdorf, R. Schuhmann, Jr.. and P. T. Stroup. Institute of Metals Division: Robert Maddin, Chairman. F. Lincoln Vogel, Jr., Vice-chairman, W. A. Backofen, R. W. Balluffi, J. H. Bechtold, M. B. Bever, R. S. Busk, C. G. Goetzel, Paul Gordon, C. D. Graham. Jr., Robert F. Hehe-mann, R. I. Jaffee, F. E. Jaumot, Jr., lrving R. Kramer, A. J. Leno, Horold Margolin, C. J. McHorgue, Russell A. Meussner, J. 6. Newkirk, H. W. Paxton, G. E. Pell~ssier, I. S. Servi, Alan U. Seybolt, A. J. Sholer, and Sack Wahsburn. Iron and Steel Division: J. C. Fulton, Chairman; T. B King, F. C. Langenberg, W. O. Philbrook, and T. B. Winkler. Published bimonthly by the American Institute of Mining Metallurgical and Petroleum Engineers Inc., 29 West 39th Street, New York 18, N. Y. Telephonne pennsylvania 6-9220.Petroleum Subscription Engineers$20 per year for non-AIME members in United States and North South and Central 6-9220.SubscriptionAmerica $25 toreign; $5 for AIME members. Single copies, $4.00, iinalo copies Southfpr;ign,andCentral $5 00. The AIME 'is $25not responsible for any statement made or opinion expressed in its publications Copyright 1958 1958 by the American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc. . Registered coble address, AIME New York . . . Indexed in Engineering Index, Industrial Arts Index, ...and Chemical Abstracts . . . Application for second class mail privileges IS pending at New Yark, N. Y. Volume 212, Number 2.

Jan 1, 1959

Jan 1, 1879

By John V. Beall

GOING west from Denver on Route 6, the direct road to Grand Junction, one gets the first glimpse of mining a few miles east of Denver near Idaho Springs where the workings of defunct gold mines are visible on the sides of mountains along the highway. One enterprising company is turning a profit by showing tourists through the mine and mill and then selling them gold samples on the way out. We have always known that mining people are ingenious, but this proves it. About five and a half hours fast driving west from Denver brings one to Rifle, Colo., which is the site of the oil shale mine, retorting plant, and refinery of the U. S. Bureau of Mines. As you drive up to the mine, you can see a portal high on the face of the cliff in front of you where the mine surface plant literally hangs by its toenails. Below, the retorting plant and refinery gleam in the sunlight. Up at the mine, Fred Wright will show you how the oil shale is extracted in two benches (a third bench would be used for commercial mining) by the room-and-pillar method. In mining the top level, an underground crew of thirteen men have been able to produce 1500 tons of shale in each eight-hour shift. To do this, the mine is thoroughly mechanized. The mining method is de- scribed in the September issue of Mining Engineering.

Jan 1, 1949