Search Documents

By Alan M., Bateman

MR. JORALEMON'S dispassionate discussion of this subject in TECHNICAL PUBLICATION 340 of the Institute shows clearly some of the failures and successes of geology in the discovery of ore deposits. He forces us to recognize, with humility, that chance has played a greater part than geology in the recent discovery of several great copper deposits. I think, however, he wrongly ascribes to unexpected or chance discovery some deposits that were found as a direct result of geological investigation. I refer to the Rhodesian copper deposits,, particularly Roan Antelope and Mufulira, both mentioned by him as having been found by chance. Also,. I think Mr. Joralemon's paper, inadvertently, does not- give the proper credit for the early recognition of the possibilities of these deposits. I feel sure that Mr. Joralemon and the gentlemen given credit by him will welcome any further information on this subject that will throw light on what will some day- be of. historical interest and importance. Consequently, I should like to set forth some additional data that throw light on who should receive the most credit, and' to indicate that, in my opinion, sound. geological reasoning and not chance is to be, credited for the development of the. Roan Antelope and Muf ulira mines.

Jan 1, 1931

By Thomas Leonard Watson

SULPHIDE ore-bodies of more or less lenticular shape occurring in metamorphic crystalline schists, gneisses, and. slates, and conforming closely in strike and usually in dip to the inclosing rock, have been recognized and described along the, Atlantic seaboard from Quebec to Alabama. The ore-bodies do not entirely conform, in all cases, to the structure of the inclosing schists, but they sometimes cut across the foliation in dip, though conforming more closely with the direction of strike. In composition the principal sulphide mineral is usually pyrite or pyrrhotite; or both, accompanied by copper, frequently gold, and almost always some sphalerite and galenite. Other. metallic ores are, so far as these sulphide bodies have been investigated, less common; silver is not uncommon, and in some of the pyrrhotite masses nickel is present in quantity sufficient to be commercially valuable. Cobalt frequently accompanies .the nickel, usually in smaller amount, and the two vary much in relative proportion. Quartz and calcite are probably the most common of the, non-metallic minerals. A number of silicate minerals are frequent representatives in one place or another; garnet, amphibole, biotite, pyroxene, zoisite and others. The sulphide bodies of Virginia, comprising both pyrite and pyrrhotite, are among the most extensive along the Atlantic seaboard. Among the pyrite bodies may be mentioned the well-known and extensively worked mines of Louisa and Prince William, counties, located on' the main pyrite belt (A, Fig. 1) of the middle and northern, eastern Piedmont region in Virginia, and among the pyrrhotite bodies is the famous " Great Gossan Lead "(B, Fig. 1) of the Floyd-Carroll-Graysou coun-

Sep 1, 1907

Prof. J. C. BRanner, Stanford University, Cal. (communication to the Secretary): On p. 398, Mr. Hedburg mentions Marionite and Brannerite as ores of zinc. Neither of these has been authoritatively recognized as a distinct mineral species. Marionite, originally described by Elderhorst, was subsequently determined to be nothing else than hydrozincite. Analyses of the so-called Brannerite were sent by me to Prof. Penfield, who says it is a mixture of Smithsonite with some other mineral. On p. 398, Mr. Hedburg says the zinc-bearing formation of North Arkansas " is recognized as the Upper Silurian." So far as my observation goes, the ores occur both in Lower Carboniferous and in Ordovician or Lower Silurian rocks, but nowhere in rocks known to be of Upper Silurian age. If Mr. Hedburg has any paleontological evidence of the Upper Silurian age of these rocks, or of any of them, he will confer a favor upon geologists by making it known. On the same page is another statement in which I cannot concur. He says that in this region, " it can easily be seen that the largest fissure-deposits have been eroded and washed away, leaving here and there a few patches adhering to the hillsides." I am compelled to say that in many years' study of the geology of the region in question, I have never been able to recognize such a state of affairs as Mr. Hedburg here describes. The patches which he regards as remnants of fissure-veins, " adhering to the hillsides," I have found to be either the edges of bedded deposits, or portions of the zinc-bearing breccias, formed along old drainage-lines, and laid bare by the ordinary processes of erosion. That fissure-deposits have been partly removed by the same agency, goes without saying; but it is, in ,my judgment, no more true of North Arkansas than of any other mining-region that erosion has selected and washed away " the largest " deposits. My own views of the region in question are given in detail

Jan 1, 1902

By Louis D. Huntoon

SHORTLY after publication of the article in the July, 1924, issue Of MINING AND METALLURGY, entitled "Canada as a Gold Producer," requests were received to determine the ownership of production. Advices have also been received that considerable discussion has taken place on the same questions both in Canada and Great Britain. The author is indebted to R. H. Coates, Dominion Statistician, and George C. Bateman, Secretary, Ontario Mining Association, for the following figures and takes this opportunity of expressing his appreciation. There have been no statistics compiled as to ownership of production. Statistics were compiled as of Dec. 31, 1921 relative to the distribution of stocks, bonds and "other securi¬ties" in industrials, agriculture excepted, throughout the Dominion, and "distribution of ownership of securities issued by mining companies incorporated and operating in Ontario" for the same year. Stock registration does not necessarily represent actual ownership' as large blocks may be endorsed and not transferred; neither does registration actually represent production. When the charts are studied individually and collectively one cannot help but be impressed with the fact .that in the mineral industry of Ontario and the Dominion at large, Canadian registration predominates, the United States registration is about half that of Canada, and Great Britain is about half that of the United States. When the nickel-copper industry is excepted the British registration falls to a very low percentage. Since Dec. 31, 1921, British capital has commenced to flow into mining enterprises in Ontario and it has been already rewarded by the discovery of valuable ore deposits.

Jan 1, 1925

COLUMBIA SECTION STANLY A. EASTON, Chairman, FREDERIC KEFFER, Vice-Chairman, L. K. ARMSTRONG, Secretary-Treasurer, P. 0. Drawer 2154, Spokane, Wash. D. C. LIVINGSTON FRANK A. Ross The first meeting of the Columbia Section was held on March 24, as a part of the 1916 Northwest Mining Convention which was held under the -auspices of the Spokane Mining Men's Club assisted by the Spokane Chamber of Commerce, the technical program being in charge of the Spokane Engineering and Technical Association assisted by the local sections of the A. I. E. E., A. S. C. E., and A. I. M. E. The program of the successive sessions was carefully arranged with view to its application to mining, and in addition to the technical program there were exhibits of ores, minerals, devices, etc., of interest to the delegates, who numbered over 500. A portion of the program was also arranged with special reference to the requirements of the prospector and miner. A reception, a banquet, a complimentary luncheon, a regular daily call' of the Stock Exchange, a visit to the High Schools and to one of the substations of the Washington Water Power Company and to the Union Iron Works kept the visitors entertained, the ladies being looked after by a special committee of ladies who held open house during the entire week. Several important resolutions were passed by the Convention and one by the Columbia Section, A. 1. M. E. With Stanly A. Easton, chairman, presiding, the Columbia Section, American Institute of Mining Engineers, occupied the time between 2.00 and 5.30 p.m., March 24th, the Moorish room of the Spokane hotel being filled with members and their guests. "The Apex Law and the Mineral Surveyor" was a paper presented by F. W. Callaway and generally dis-cussed because of its local application in the Coeur d'Alenes, the conclusions being reached after expensive litigation between two of the large mining operators in that district.

Jan 6, 1916

By C. R. Fast

In order to evaluate the ability of a Hydrafrac treatment to effect a sustained increase in well production, data were accumulated on the first 65 wells in 26 fields treated by Stano-lind. Since these data were obtained from such a large number of fields, it is felt that individual well or reservoir characteristics do not affect the overall picture, as might be the case if the study were made in one field or one group of wells in a field. These data are tabulated in Table I and plotted on Figs. 1 and 2. An analysis of Fig. 1 shows that at the end of six months, 75 per cent, or 45, of 60 wells on which data were available showed a sustained production increase. At the end of two years, data were available on 25 wells. Of these, 15 wells, or 60 per cent, showed a sustained production increase. At the end of three years, 55 per cent, or 10, of 18 wells had a production rate greater at that time than before Hydrafrac treatment. The lack of information on additional wells at the end of the third year is primarily a result of the small number of treatments conducted in the early stages of field application

Jan 1, 1952

By R. W. Raymond

THE absence of a convenient glossary of terns connected with mining and metallurgy has long been felt by the general public. It is to meet this want, not to furnish a technical manual for experts, that the following glossary has been prepared. It originated in an attempt on my part to revise for publication the manuscript of a compilation prepared from the appendix of Yale's work on Mining Titles and one or two other sources, to serve as an appendix to a new work on mining law, about to be published by Mr. H. N. Copp, of Washington, D. C. This revision soon assumed, contrary to my original intention, the proportions of a reconstruction ; and with the consent of Mr. Copp, and for the purpose of receiving from my fellow-members valuable aid, I presented my still incomplete work as a paper at the Lake Superior meeting of the Institute, inviting from any quarter suggestions of new terms or better definitions to be incorporated in the glossary before its final publication. This invitation was so widely and generously responded to, that I cannot undertake to make in this place' individual acknowledgments to those members of the Institute, and professional colleagues outside of it, who hays favored me with ' assistance and advice. The labor bestowed upon this paper since its presentation, at the Lake Superior meeting has considerably exceeded that of its first preparation, as

Jan 1, 1881

State of Louisiana, Department of Conservation, Division of Minerals, 126 New Orleans Court bldg , New Orleans, La. Dr. J. A Shaw, Director The Bureau of Scientific Research of the Minerals Division has recently issued the first of a proposed series of Geological Bulletins on the geology of Louisiana, by parishes The bulletin may be had for 25 cents postage by writing to the above address: Geological Bulletin 1, Geology of Iberia Parish (1931) Other bulletins of a more general nature have been published in the past. Bulletin 13, A brief survey of the natural resources of Louisiana (1930) (revised 1931), 14, The clays of the Shreveport area (1927), 16, The clays of Monroe area (1928), 19, The clays of Alexandria area (1929). The latest (Tenth) Biennial Report of the Department of Conservation for 1930-1931, containing a review of the natural resources of the state in the report of the Division of Minerals, may be obtained on payment of 25 cents for postage

Jan 1, 1933

By Joe B. Alford

Jan 1, 1971

By R. S. Shoemaker, F. W. McQuiston

CARLIN GOLD MINING COMPANY 1974 Operating Data to October MINE LOCATION: 40 miles from Elko, Nevada ORE DESCRIPTION: Gold with minor amounts of mercury occurring in siltstone and carboniferous limey shales. TYPE OF MINE: Open pit ORE HAULAGE TO MILL: By trucks up to a distance of 12 mi1es MILLING CAPACITY: 2500 tons per day ORE GRADE: 0.20 oz per ton oxide ore 0.25 oz per ton carbon type ore PRODUCTS: Gold bullion 993 fineness, by product quicksilver RECOVERIES: Oxide ore 887'0 Carbon ore 83% POWER FOR GRINDING: 7 Kwh/T POWER, other than grinding: 14 Kwh/T WATER SUPPLY: Pumped from wells 2- 112 miles through 13,000 ft of 8" buried pipe 6 ft underground. Consumption 0.60 tons of new water per ton of mill feed. TAILINGS: By 10" woodstave pipe a distance of 2500 ft to mine waste filled dam. RUNNING TIME: 10 ft x 10 ft mill on oxide ore, 98% 7 ft x 8 ft mill on carbon ore, 937'0 Principal causes of lost time, power outages and problems of feeding gaseous chlorine to carbon ore agitators. LABOR, TONSIMAN SHIFT: See detailed data sheet ILL BUILDING DESCRIPTION: Framed structural steel with sandwich type walls of marine plywood, then packaged pre - fabricated insulation and outer sheeting of galvanized corrugated steel.

Jan 1, 1975

By A. M. Beebee

IN the present century the coal and manufactured gas industries have been eclipsed in public interest by oil, natural gas, and hydro- electric energy, which have had the benefit of rapid development and novelty. I sometimes wish that our social- order were such that hydro power had been developed first, that the use of gas from coal had never been seriously considered, and that our domestic energy requirements were supplied by other fuels. Sup- pose the manufacture of gas from coal should then come on the scene at the present time with the current plight of the railroads, coal regions, and labor generally, presenting the fact that it could increase the amount of coal mined and shipped by the railroads by some 16,000,000 tons, and increase the coal used at existing u plants five times. Imagine the great public interest that would be manifested; it would supply the cooking and water-heating requirements of a community with a superior character of service at a cost to the customer approximately half that which had obtained previously. Would not such a situation be heralded as the salvation of our country and all help be given it?

Jan 1, 1940

By J. Ruben Velasco, Roland B. Mulchay

CANANEA has long been recognized as a remarkable field for geologic study. The copper deposits and rocks of the district have been described by many geologists and engineers, but only the most general correlations have been made between Can-anea sedimentary rocks and other known sedimentary sections in the southwestern United States and northern Mexico. The present paper describes the Cananea sediments in greater detail than has been done before and attempts to fit the Cananea sedimentary section more closely into the geologic time table. The lack of well-preserved fossils has made it difficult to date the sediments accurately in geologic time, but it is possible to make tentative correlations between the Cananea sediments and the southeastern Arizona sections, based largely upon lithology and general position in the geologic column. It appears that sedimentation at Cananea and Bisbee may have been closely similar during Paleozoic time. Even such generalized correlations, however, may be subject to considerable modification in the future. The present study has led to the recognition of other problems of age and mineralization relationships in the Cananea district. Cananea is located in the north-central part of the state of Sonora, Mexico, at an elevation of 5270 ft. It is about 135 miles northeast of Hermosillo, the state capital, and 25 miles south of the international boundary. By road Cananea is 40 miles from the twin towns of Naco, Ariz., and Naco, Sonora, and about 50 miles from Bisbee, Ariz. It is served by the Nogales-Naco branch of the railroad, F.C. Pacifico, and is connected with Chihuahua and Mexico City by the Aeronaves airline. The headwaters of three rivers flowing to the Gulf of California are located in the Cananea Mountains: the San Pedro River, flowing to the north; the Sonora River, flowing south and west; and the Mag-dalena River, flowing west. Elenita Mountain, the highest point in the district, has an elevation of 8140 ft. The Cananea Mountains extend in a series of north-south to northwest-southeast spurs and ridges and are surrounded by gently sloping gravel plains. The mineralized area, lying across the southern and central parts of the range, is about 6 miles long and at most 2 miles wide. Elevations at the mines vary from 5300 ft at Cananea-Duluth mine at the southeast end of the district to between 6000 and 7000 ft at the west end of the mineralized area at Puertecitos-Elenita mines. Principal production has been from the intensely mineralized and altered area of Capote Basin in the central part of the district and the immediately surrounding area to the southeast. The district has produced over 2 billion lb of copper, substantial molybdenum, and minor amounts of lead, zinc, silver, and gold. Total production through 1949 is estimated at more than $300 million. In 1900 large-scale development was started at Cananea by W. C. Greene. Until World War II only high-grade ores were exploited; low-grade ores were extracted after the installation of a large concentrator in the early 1940's, and subsequent operations have been based upon mining and processing ores containing less than 1.0 pct copper from open-pit and underground workings. Mining and concentration of such low-grade ores, however, are made possible only by continued high copper prices, and active exploration for high-grade orebodies has been continued throughout the important mineralized areas. General Geology Study of the involved rock pattern at Cananea has indicated a complex geologic history for the district. Widespread alteration and mineralization have masked many of the salient features and have led to widely varying geologic interpretations over the years. Further work will probably disclose new information which will modify current beliefs. At Cananea a conformable series of sediments of probable Paleozoic age was deposited on an unknown basement. Following Paleozoic time there was an extended period of erosion common to many districts in the southwestern U. S., and there is no present evidence of marine sedimentation at Cananea after the Paleozoic. The eroded surface was eventually covered with a great thickness of extrusive volcanic rocks. The entire series of sediments and volcanic rocks was later intruded by a variety of deep-seated igneous rocks. These included the Cananea granite, the Cuitaca granodiorite, the El Torre syenite, the Tinaja diorite, the Campana diabase and gabbro and the Colorada rhyolite quartz porphyry. Faulting of early age, probably prior to the deposition of the volcanic rocks, may have been responsible for the present position of some of the intrusive rock masses. In the Capote mine on the third and fourth levels the northwest-striking Rick-etts fault zone, with apparent offset of about 800 ft, has been sealed by a dike-like mass of Cananea granite which gradually increases in size with depth. In lower levels of the mine the granite forms a large southeast-plunging mass generally following the course of the Ricketts zone. The granite is not known southeast of the Capote-Oversight mine areas and the Ricketts fault does not appear in the vol-canic~ southeast of Capote Basin, but several plugs of Colorada quartz porphyry cut the volcanics along the assumed general southeast trend of the Ricketts zone. These porphyritic intrusives may be the up-

Jan 1, 1955

By Henry F. Adams, Guy H. Ruggles

IN this paper the authors aim to chronicle the experience and salient points brought out in changing flotation reagents at a concentrator which had probably been using a mininium amount of oil at a minimum cost per ton, to a more complicated system requiring a partial chemical control. The original oils were coal tar and pine oil. The new reagents are lime, xanthate and pine oil. It was found that there were no insurmountable difficulties and eventually the cost of the new reagents per ton of ore proved to be very little more than that of the old. LIME PLANT When the question of handling lime came up there were two propositions open: (1) to handle the lime dry; (2) to handle it wet in the form of an emulsion. Granting that a dry lime feeder would function properly, delivering lime uniformly, the chief objection was the dust that would be raised when these feeders were being charged or operated, as the only possible location was on a gallery beneath which men were working. With this objection the handling of lime as an emulsion seemed to be the better scheme. The lime plant which was first installed was for experimental work on one section. This was gradually changed and developed until it was of sufficient size to accommodate 20 sections. The various changes will not be discussed and the following description deals only with the fully developed plant. Crude as it is, and perhaps somewhat expensive to operate, the lime-handling plant has been quite successful. Much has been learned which will pave the way for a better installation in the future. Burnt lime is received loose in standard gage box cars. This is the product of the kilns and has had no screening or sorting. A grab sample is taken from each car as it is unloaded. An average of the analyses of samples from 44 cars gave the following: [ ]

Jan 1, 1928

AARONS, J. BOYD; Major. AGNEW, FRANK VANS. ALLEN, HERMAN H., Private, D Co., 8th Reserve Engineers. AMBLER, HARRY A., Second Training Camp,, Ft. Sheridan, Ill. BAINS, THOMAS M., JR., Major, Engineer Officers' Reserve Corps. BANKS, H. R., Lieutenant, Canadian Engineers, B. E. F. BARBOUR, PERCY E., Deputy' Supt. (Captain), New York State Troopers; Captain, 22d Regiment, N. Y. N. G. BARLING, H. B., 1st Lieutenant, Engineer Officers' Reserve Corps. BARRETT, LESLIE P., Lieutenant, A. E. F., France. (Unattached.) BENSEL, J. A., Major, Engineers' Reserve Corps. BIGELOW, BRAXTON, Royal Engineers, B. E. F. BLOOMFIELD, E. C., Lieutenant. BORROW, F. K. BOWLES, MARTIN F., 2d Lieutenant of Infantry, Camp Funston, Kans.

Jan 11, 1917

AARONS, J. BOYD, Major. AGNEW, FRANK VANS. ALLEN, HERMAN H., Private, D Co., 8th Reserve -Engineers. AMBLER, HARRY A., Second Training Camp, Ft. Sheridan, Ill. BAINS, THOMAS M., JR., Major, Engineer Officers' Reserve Corps. BANKS, H. R., Lieutenant, Canadian Engineers, B. E. F. BARBOUR, PERCY E., Deputy Supt. (Captain), New York State Troopers; Captain, 22c1 Regiment, N. Y. N. G. BARLING, H. B., 1st Lieutenant, Engineer Officers' Reserve Corps. BARRETT, LESLIE P., Lieutenant, A. E. F., France. (Unattached.) BENSEL, J. A., Major, Engineers' Reserve Corps. BIGELOW, BRAXTON, Royal Engineers, B. E. F. BLOOMFIELD, E. C., Lieutenant. BORROW, F. K. BOWLES, MARTIN F., 2d Lieutenant of Infantry, Camp Funston, Kans.

Jan 10, 1917

NEW YORK SECTION ALLEN H. ROGERS, Chairman, H. C. PARMELEE, Vice-chairman, FOREST RUTHERFORD, Vice-chairman, W. S. DICKSON, Secretary, 71 Broadway, New York, N. Y. J. E. JOHNSON, JR. . F. T. RUBIDGE, Treasurer, P. G. SPILSBURY. The annual meeting of the New York Section, for the election of officers and other business, was held at the Machinery Club on May 23,

Jan 8, 1918

By James C. Ray

DURING the summer of 1931, I spent four months in a study of the Willow Creek district, Alaska. This work was part of a general investigation of the territory contiguous to the route of the Government- owned Alaska Railroad. It was conducted by the U. S. Geological Survey to determine the real and potential merits of the mineral deposits, to stimulate development of them, and thus to increase the traffic on the Alaska Railroad.

Jan 1, 1932

By R. M. Larsen

The Rocky Mountain region is defined with some variations for different purposes or by different organizations. For oil and gas development, Wyoming, Montana, Colorado, northwestern New Mexico, and Utah are included in the order of their apparent importance. Portions of adjoining states, such as North and South Dakota, Nebraska, Arizona, Nevada, and Idaho, arc attributary to this region, but have little or no oil or gas production. Nebraska and New Mexico are considered separately (see pp. 412 and 415), and most of the discussion in this report will be confined to Colorado, Montana, and Wyoming. Utah has produced about 200,000 bbl. of oil from the San Juan and Virgin fields, which are isolated and shut in at present. The Clay Basin field in northeastern Utah produces natural gas and distillate, and the Farnham field in central Utah produces carbon dioxide gas. Other Utah areas of some interest are listed in Table I. The Cedar Creek (Baker-Glendive) field in southeastern Montana extends into North Dakota, but is listed under Montana. The other states are in the main wildcat areas, and exploration in 1944 was at a minimum. However, geological and geophysical parties are reviewing them for further testing. Oil production in Colorado, Montana and Wyoming was 459,000 bbl. more than in 1943. Increases of 713,000 bbl. in Colarado and 731,000 bbl. in Montana offset a loss of 985,000 bbl. in Wyoming. This was the first decline in Wyoming since 1938. Field production figures and state totals are given in Table I. Total drilling activities in these three states and Utah increased from 687 wells making 1,442,511 ft. of hole in 1943 to 916 wells making 2,245,803 it. in 1944. Wildcat drilling increased from 163 wells making 331,193 ft. of hole in 1943 to 171 wells making 389,144 it. in 1944. These figures include all drilling wells making footage, not starts or completions, and represent an all-time high in drilling. The year 1944 witnessed the greatest concentration of seismograph activity that the region has had. The Rocky Mountain Oil Scouts Association reported that in 1943, the previous peak year, 91 crew months of work were performed; in 1944, the time was 254 crew months. About 67 per cent of the work was in Wyoming, 18 per cent in Montana, and 12 per cent in Colorado. Twenty-three blocks totaling 400,000 acres were reported assembled in Colorado, and 161 blocks totaling 4,000,000 acres in Wyoming. Information about other states was not given. Fourteen unit agreements were approved by the Department of the Interior, as compared with 13 in 1943. The 1944 agreements were all in Wyoming. In five of the unit areas, oil or gas discoveries were made, four were dry, and five were drilling Or pending' Oil companies find it advantageous to unitize blocks containing any proportion of public domain. Units for

Jan 1, 1945

By C. K. Leith, W. J. NEAD

(Glen Summit Meeting, June, 1911.) . ONE Of the most significant developments in the iron industry in recent years has been the discovery and opening of enormous reserves of low-grade ore in eastern and northeastern Cuba. The two principal fields are the Mayari and the Moa, situated on Nipe bay, in the Province of Oriente. A less well-known district of the same type is that of Baracoa, at the east of the island, and another is in Camaguey province in central Cuba. In the comprehensive estimates of the iron-ore reserves of the world, published during the summer of 1910 by the International Geological Congress in Sweden,' these Cuban deposits are estimated at about 2,000,000,000 tons. Certain it is that the reserve is a large one. The Spanish-American Iron Co., the Juragua Iron Co. (Bethlehem Steel Co.), the U. S. Steel Corporation, and others have been active in this exploration.. The Spanish-American Iron Co. has established a port for the handling of these ores at Felton, has built a railway 16 miles to the ore-fields, and has opened up deposits for steam-shovel mining. Its expenditures have reached an aggregate of about $6,000,000 in preparation for the handling of these ores. Shipment of the ore to Sparrow's Point, Md., has begun and may be expected to rise to a considerable amount in the near future. The ore reaches this point at a cost per unit of iron considerably lower than Lake Superior ores, and the presence of a low percentage of nickel gives a desirable steel. It is not the purpose of this article to consider these ores from a commercial stand-point, but rather to discuss their-origin. If our conclusions are correct, they throw light on the character of the deposits which should have some commercial significance. 1 The Iron Ore Resources of the World, an inquiry made upon the initiative of the Executive Committee of the Eleventh International Geological Congress, Stockholm, vol. ii., p. 795 (1910).

Mar 1, 1911

By Kenneth K. Humphreys, Joseph W. Leonard, Robert L. Llewellyn, William C. McCulloch

INTRODUCTION The particular field of application of machines utilizing air currents as the primary separating medium is in the cleaning of the fine sizes of bituminous coal. Approximately 25,400,000 tons of bituminous coal were cleaned by air machines during 1965. They have not found any application for cleaning anthracite. Since the development and introduction of the first successful commercial pneumatic oscillating machine for cleaning bituminous coal in 19 16, by the Sutton, Steele and Steele Co, Dallas, Texas, and the American Coal Cleaning Corporation, formerly of Welch, W. Va., seven other successful pneumatic coal-cleaning machines have been developed and introduced to the American coal-mining industry: 1. Peale Davis: "Pneumo-Gravity" machine. 2. Arms "Concentrator," oscillating table. 3. Hey1 and Patterson oscillating table. 4. "Stump Air-Flow," pulsating air jig. 5. "Super Airflow," pulsating air jig. 6. Ridge air jig. 7. Phillip air jig. While not all coals can be beneficiated by air washing, the air washing of coals that are easy to clean can be readily proved advantageous. Of all the preparation methods, pneumatic cleaning is the most acceptable from the standpoint of delivered Btu cost. This is based on the premise that a percent of moisture is just as detrimental as a percent of ash. The principle of dry concentration has never been determined with scientific accuracy. To the present time the study has been more of an art than a science. It is possible to forecast the results of wet concentration from a study of the washability characteristics of the raw coal but only after applying rule-of-thumb methods of interpretation to the specific gravity and size distribution can it be ascertained that the raw coal is amenable to dry concentration. Air as a separating medium dates back to biblical times as exemplified in the winnowing of chaff from the grain. However, the same application of air to coal serves merely to blow the dust away and size the remaining particles. Pulsating air was the solution to the problem and largely eliminated the necessity for close screen sizing which was required on early separators. Because of the low density of air, a medium of sufficient density has to be built with the material itself. Hence there must be some device to impart to the bed the necessary mobility for proper classification. Also, the

Jan 1, 1968