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By Rintoul AH

Studies of many types and purposes are being carried out constantly by mining, minerals processing and other operating companies. Frequently, the staff requirements and special skills lie outside the resources of the operating companies, and needs arise for external consult- ing services. We examine the natures of a range of studies, the factors that influence whether they be carried out in-house or externally and then discuss the manner of execution. Aspects of both good and bad practice are highlighted in order to arrive at the basic principles that give the most benefit from study work. While the bulk of the discussion relates specifically to the execution of external studies of process plant projects, many of the observations can be applied equally to the execution of studies by one department of a large organisation for another, and also to studies of capital projects other than those involving process plant facilities.

Jan 1, 1975

By R. Karl Zipf

In some instances, extensive room-and-pillar working scan collapse with little warning and pose a serious risk to underground miners. Traditional strength-based pillar design methods applicable to coal or hard-rock mines use a factor of safety defined as pillar strength divided by pillar stress. Factor of stability, defined as local mine stiffness divided by post-failure pillar stiffness, may offer a way to design room-and-pillar mines and eliminate collapses. Three alternative design approaches to decreasing the risk of large-scale catastrophic collapses are described: the containment approach, the prevention approach, and the full-extraction approach. Until good data on the post-failure behavior of pillars become available, the containment and full-extraction options are the safest. The limitations in our ability to evaluate both the stability of old workings and the long-term performance of room-and-pillar mines are described.

By V. I. Lakshmanan

The growing concerns on process efficiency, escalating operating and capital costs along with environmental and social concerns of using conventional technology for extracting gold and titanium dioxide demand an in-depth understanding of the fundamentals and a broader understanding of the various process steps involved. This will allow development of efficient process flowsheet for product recovery and compliance with regulatory guidelines. This paper will discuss our recent developments in mineral processing and hydrometallurgical technologies to recover gold and titanium dioxide from a wide range of feed materials including ores, concentrates and tailings.

Sep 1, 2012

Backfil ling of excavated Sub Level Open Stopes has been underway since March 1989 and as at December 1992 some 1 100 000 cubic metres of Cemented Aggregate Fill have been placed. During these three years significant developments in fill quantities, types and cost have taken place.Operational improvements have reduced the quantity of Cement Aggregate Fill by 40 per cent. These results have been achieved by:ò rescheduling stopes,ò designing smaller primary stope, and ò use of uncemented rockfill.Unit cost for Cement Aggregate Fill have fallen in the order of 50 per cent through:improving fill hole reli ability,simplified barricade construction procedures, reducing the cement content,ò substituting dune sand for deslimed mill tailings, ò improved maintenance at the Backfill plant, and ò renegotiated site freight agreement.This paper will review the historical developments of backfill use at Olympic Dam.

Jan 1, 1993

By W. F. Carew, F. A. Crossley

Tensile, creep-rupture, and stability tests were employed to evaluate the effect of a-strengthening and ß-complexing additions on the base composition Ti-6Al-3Mo. The ultimate objective was to produce an alloy of greater strength than the Ti-7A1-3Mo alloy. Strengthening of a was accomplished by additions of 2 and 4 pct Ge, 4 pct Sn, 4 pct Zr, and 2 pct Sn-2 pct Zr. Making the ß more complex while keeping the total of ß-stabilizing additions constant at 3 pct resulted in higher tensile strengths but lower creep and rwpture strengths, especially at 1000°F. None of the more complex versions of the base alloy offers greater promise than the Ti-7A1-3Mo alloy. However, some improvement in the strength of the latter may follow from additions of zirconium perhaps up to 4 pct. PREVIOUS work directed at the development of titanium-base alloys with: 1) minimum room-temperature tensile elongation of 10 pct in 1 in., 2) high creep resistance at elevated temperature, and 3) the ability to retain original room temperature tensile ductility following exposure to creep conditions at elevated temperatures, demonstrated Ti-Al-Mo ternary compositions in the range 5 to 7 pct Al-3 to 6 pct Mo to be the most promising. Of this group the Ti-7Al-3Mo alloy was the strongest.'-= The objective of the present work was to determine if alloys of this type could be further strengthened by making additions which dissolve preferentially in the a-phase and by making the ß-phase more complex. For this study the base composition Ti-6Al-3Mo was selected rather than Ti-7Al-3Mo in order to minimize the possibility that in a more complex alloy with a-strengthening additions, low ductility might obscure the strength contribution. The metals

Jan 1, 1959

By T. Hayashi

A sophisticated process of extracting ultrafine sulfide mineral particles of under 1µm size suspended in clay slurry has been developed through studies of electrochemical properties of particle surface. Experimental procedure and data of the process applied to some clay ores containing sphalerite and pyrite, and molybdenite and other sulfide minerals are reported. Discussions concentrated on the function of process reagents, particularly on various modifying reagents, and on the effect of dispersed or flocculated state of ultrafine particles in slurry which affect significantly the performance of the process.

Jan 1, 1982

By AIME AIME

The following report is published for the information of the members: Meetings. Two meetings for the reading and discussion of papers, etc., have been held during the year 1907-namely, the Ninety-second meeting, held April 16 to 20 in New York, N. Y., and the Ninety-third meeting, held July 23 to 30 in Toronto, Canada. The proceedings of these meetings, including descriptions of the entertainments and excursions connected therewith, have already been published and distributed to the members of the Institute; the New York meeting in Bi-Monthly Bulletin, No. 15, May, 1907, pp. 541 to 559, and the Toronto meeting in Bi-Monthly Bulletin., No. 17, September, 1907, pp. 847 to 875. In addition to these " Proceedings," there were also published in Bi-Monthly Bulletin, No. 15, May, 1907, an illustrated description of the United Engineering Society building (p1 vi. to xxvi.), and a record of the exercises attending its dedication, including the addresses of Andrew Carnegie, Arthur T. Hadley, Samuel Sheldon, Frederick R. Hutton, John Hays Hammond, and T. C. Martin (pp. xxxviii. to lxv.). At the New York meeting, 43 papers and- discussions were presented, and the names of 297 members and guests were registered at the Institute headquarters., this number, however, does not represent all who were present at the sessions and excursions. At the Toronto meeting, 23 papers and discussions were presented. The number of members and guests registered at the Toronto headquarters was 191, which doubtless does not include the names of all who were present at the sessions, or took part in the numerous excursions and visits around Cobalt.

Mar 1, 1908

By AIME

IRWIN W. ALCORN, present Chairman of the Petroleum Division, was born Sept. 5, 1899 at Marietta, Ohio, and moved with his family to Robinson, Ill., at the time of the early oil development there. This was in the days of the Star spudders, mud, mules, and Stanley steamers. Al graduated from Robinson High School after participation in basket ball, also attaining the captaincy of the football team of that school. He entered Missouri School of Mines and Metallurgy in 1918 and was ushered by the Army into the S.A.T.C. In 1920 he transferred to the Massachusetts Institute of Technology, later to return to receive his B.S. degree -in metallurgy at Rolla, also joining the AIME. On graduation, he worked for the Skelly Oil Co. at Cushing, Okla., shifting to the Moore Refining Co. at DeNoya, Okla., as superintendent of a small pipe-line system. After an interval of two years with the National Supply Co. in Tulsa, he joined the Independent Oil and Gas Co. of that city, and at various times was chief engineer of the Texas division, superintendent of the West Texas pipe-line system, chief engineer of pipe-line construction, and chief engineer of the refining division. Al organized the Company's production engineering department. In 1930 the Company was merged with the Phillips Petroleum Co. The depression was in and Al was out, 'as was true nine months later when the Smith Separator Co. whose chief engineer he had become, was liquidated. The next few years was spent with Oil Well Supply Co. as a subsurface pumping equipment engineer

Jan 1, 1948

By Ralph Arnold

Since 1915, when Elk Basin field was brought in, eight oil fields have been developed in Montana and the production has arisen from 50,000 bbl. in 1916 to 8,000,000 bbl. in 1926. The production for 1927 was 5,121,600 bbl. and the total up to the end of 1927 was 27,138,239 barrels. The eight fields, with their year of discovery are: Elk Basin, Carbon County (1915); Devil's Basin, Petroleum County (1919); Cat Creek, Petroleum County (1920); Soap Creek, Big Horn County (1921); Kevin-Sunburst, Toole County (1922); Lake Basin, Stillwater County (1924); Pondera, Pondera and Teton counties (1927); and Bannatyne, Pondera and Teton counties (1927). About 170 wildcat wells have been drilled in the state of which 8 were successful and 162 gas wells or dry. Hence, only one out of 21, or 5 per cent. of the wildcats have been successful. The average depth of the wells has been 1600 ft. and the average cost $32,000 apiece. • Up to Jan. 1, 1927, a total of 1376 wells have been drilled in the producing oil and gas fields of the state, of which 904, or 66 per cent., were successful oil wells; 82, or 6 per cent. were gas; and 390, or 28 per cent, were dry. The percentage of dry wells is excessive as compared to the wells in other states, due to the uncertainties of limestone reservoir rocks. The total production of oil to Jan. 1, 1927, has been 22,016,639 bbl. and of gas 7,265,330,000 cu. ft. The average price at the well for the oil has been $1.47 per bbl. and for gas about 4 c. per 1000 cu. ft. The value at the point of consumption has been about 23 c. per 1000 cu. ft. The total revenue derived from crude oil has been $32,277,119, and from gas 8350,613, or a total income to the producer of $32,727,832. Each well drilled in the state has already (to Jan. 1, 1927) averaged a return of over $21,000. The total number of domestic (Montana) oil and gas companies organized, since the first in 1885, has been 844, of which 702 are still alive and 142 dead. Oil and gas companies registered for operation within the state to Jan. 1, 1927, but with outside charters, are 143, of which 66 are alive and 77 are dead. Outside the few distributing companies, which are included in these figures, the grand total of 997 companies which have

Jan 1, 1928

By Roy A. Lindgren

SINCE the year 1643, when the first blast furnace in America for treating iron ore was built at Saugus, Mass., out of mica schist quarried in the neighboring district, the procurement of a suitable refractory for furnace lining has been a problem of concern to the operators of furnaces. The stacks built of mica schist continued to smelt iron ore until about 1836, when, according to F. H. Norton, the first firebrick were produced', at Queens Run, Pa. Other writers speak of brick having been molded and burned in Massachusetts about the year 1834. In 1841, Andrew Russell began to produce medium refractory plastic clay brick near East Liverpool, Ohio, that were used for lining blast furnaces'. The well-known Kentucky clay-producing district was not opened up until the year 1871, but since then it has produced a large percentage of the linings for iron blast furnaces. While some strides have been made by the refractories industry during the 100 years that have passed since the first firebrick were produced, it has been only during the last two decades that any real progress has been made towards bettering the product, even though the method of production had improved. Perhaps the fault lies with the user of the brick rather than with the producer, for not sooner demanding a supe¬rior product. During the past 15 years the tonnage produced per lining has increased from 500,000 gross tons to 1,000,000 gross tons, and now some furnaces are producing 1,600,000 gross tons and better on a single lining. It is true that enlarged capacity of furnaces and improved practice have accounted for some of this increase in tonnage, nevertheless better quality in firebrick must be given credit for its share. However, we are not yet ready to say that we have reached a maximum life of furnace lining. We believe that a better product can be produced and that the refractories industries of America will, through their extensive research depart-

Jan 1, 1937

The November General Meeting of the Branch was held in the St. Helena Club at 8.00 p.m. on the 17th November, 1970. Mr J. N. Saunders (Chairman) was in the chair. There were also present six fellows, N. A. Honnet, C. J. Isaac, J. G. Kirchner, (Committee Members), J. M. Meyer, S. L. S. Swart and J. W. Wilson; seven members, D. V. Baum, M. de Lange, A. H. Edwards, G. J. G. Emere, E. R. Penny, G. P. Rundle, C. G. J. Vermeulen; six graduates, N. Mayer, H. Miller, E. J. Shillaber, P. J. H. Short, M. H. Smith, T. R. Stromsoe; five associates, M. Andriesse, A. E. Hooper, A. Paschalides, R. L. Solms, W. M. Todd; one student, J. C. Simms and 14 visitors. Apologies for absence were received from Messrs L. O. W. Leimer and G. Y. Nisbet. MINUTES OF THE ANNUAL GENERALMEETING The Minutes of the Annual General Meeting held on the 27th August, 1970, were taken as read. Their adoption, which was proposed by Mr N. A. Honnet and seconded by Mr J. G. Kirchner, was carried unanimously. MINUTES OF THE JULY GENERALMEETING The minutes of the General Meeting held on the 8th July, 1970, were taken as read. Their adoption, which was proposed by Mr C. J. Isaac and seconded by Mr J. G. Kirchner, was carried unanimously. GENERAL BUSINESS Members were advised that no more applications could be entertained for the visit to Western Holdings; they could, however, still apply to visit Welkom Mine and Harmony. TALK The Chairman invited Mr A. Paschalides to deliver his talk on 'Controlled blasting in stopes and new explosives developments'. The presentation proved to be of great interest to the meeting and lively discussion followed the talk. Mr N. A. Honnet proposed a vote of thanks to Mr Paschalides on behalf of all members of the O.F.S. Branch. CLOSURE The Chairman thanked Mr Paschalides for his talk and all present for their attendance, and as this was the last meeting for 1970 he wished all members a Merry Christmas and a Happy New Year. He declared the meeting closed at 9.30 p.m.

By H. M. Dess, S. R. Bolin

A modifiedl Czochralski technique has been utilized to grow single crystals of YVO, pure or doped with europium or neodymium, from 1 to 2 in. long and 4 to 1/2 in. in dianz. An oxyhydrog-en gas-fired furftace zuas used in this ulork, and melts were contained in iridium crucibles. Successful application of the Czochralski ~vzethod was found to depend upon atmosphere control to prevent crusting and to limit melt decomposition, the establishment of symmetrical thermal gradients in the melt to obtain stable growth, and the selection of high-quality single-crystal seeds to prevent propagation of misorientations during growth and subsequent catastrophic cracking. The suitability of YVO4 as a host for laser-active trivalent rare earth ions has long been recognized. However, the problems associated with the growth of sufficiently large, good-quality single crystals have, until quite recently, seriously hindered satisfactory evaluation of the laser potentialities of this material. Both flux growth and Czochralski growth techniques were investigated at an early stage of interest in YVO,. The former method proved incapable of yielding crystals large enough for practical use,ly2 and the latter was beset with difficulties which took some considerable time to understand and overcome. Recently, however, the Czochralski growth process for YVO, has been improved along separate but similar lines of development by groups working independently in the Crystal Products Department of Union Carbide's Electronics Division and Bell Telephone Laboratories3 so that now good-quality single crystals of satisfactory size can be produced on a routine basis. Stimulated emission from a neodymium-doped YVO4 crystal grown by the Crystal Products Department of Union Carbide was obtained by O'connor4 of MIT, Lincoln Labs. An oxyhydrogen gas-fired furnace was used in this work, Fig. 1, and melts were contained in iridium crucibles. The starting material was 99.9 to 99.99 pct pure YVO4 powder purchased from the Chemical and Metallurgical Division of the Sylvania Electric Products Co. Typical impurity levels, determined by spectrographic analyses, were as follows: Si, 50 to 500 ppm Al, Fe, Mg, 5 to 50 ppm Ni, Pb, Mo, Mn, Ce, Cs, 1 to 10 ppm Initially, YV04 powders predoped with neodymium or europium were obtained from Sylvania. Later, however, because of a desire to grow a series of crystals containing relatively broad concentration ranges of these dopants, it proved more convenient to start with pure YV04 and mechanically admix Nd2O3 or Eu@~ powders plus equimolar amounts of V2O5. The empty crucibles were preheated to 1900" to 1950oC, a temperature range where melting occurred readily. The powdered YVO4 feedstock was then added incrementally. However, a marked tendency toward

Jan 1, 1968

[Following is the Financial Report of the Treasurer from May 22, 1981 to May 21, 1982: RECEIPTS Cash on hand May 22, 1981 $21,815.81 Dues $ 6,800.00 Registrations 19,250.00 Banquet, luncheons, Buffet and Steak Fry Tickets $44,335.00 Less adjustment 831.68 43,503.32 Bank Interest and Certificate Interest 7,747.49 77,300.81 $99,116.62 DISBURSEMENTS Convention Expense - 1981 48,600.37 Convention Expense - 1982 2,146.65 Stamps & Stamped Envelopes 1,251.48 Stationery & Office Expense 1,259.22 Salary of Secretary-Treasurer 5,040.18 Social Security & Employment Tax 772.20 Proceedings $ 9,703.42 Less Advertising 2,290.00 7,413.42 Certificate Purchase 10,000.00 76,483.52 Cash on hand May 21, 1982 22,633.10 United Bank of Denver Savings Account 15,000.00 Money Market Certificates 40,000.00 Total Assets $77,633.10 AUGUSTA WHITESIDE Secretary-Treasurer Approved by Auditing Committee: Paul Hronich, Chairman Robert Anderson Allen E. Duncan Donald P. Huckeby Richard C. Mullins June 29, 1982]

Jan 1, 1982

By W. H. Adams

During the years when Americans were most active in investigations of the many substances containing nitrogen or ammonia, viz.: 1869 to 1875, my connection with certain chemical industries led me to experiments in the direction of the recovery of wastes from coal-gases. I take from my notes such memoranda as I think will be of interest, in the hope that some benefit may be derived therefrom by engineers at present attempting to utilize the waste products from coke-oven and blast-furnace gases. An examination of the conditions governing the manufacture of gas along the Atlantic seaboard, and an intimate knowledge of the mine-products used by the different large works, naturally led me at first to consider the well-known foreign methods of concentrating the available soluble salts in a modicum of water. The result was sufficiently promising to warrant a full line of experiments. At that time, no attention seemed to have been paid to the values of " gas-liquors." Nearly every gas-works in the United States wasted its wash-water in the sewers. The nitrogen in bituminous coals varies in quantity from 0.75 to 1.50 per cent. of the total weight. In the process of distillation in

Jan 1, 1887

By Larry D. Hartzog

For detailed information you are referred to "Heap Leach Solution Application at Rochester" by S. N. Dixon and A. L. Wilder which will be presented at the SME Meeting in Phoenix, January 1988.

Jan 1, 1998

By LaBrooy S. R

Crushing for the gold industry involves fine crushing and a degree of primary milling, and this presents new problems and challenges, partiuclarly on many of the new ore-bodies now being opened up. All of this calls for a better understanding of some of the basics of fine crushing and milling. Accordingly, in this paper the "typical" contemporary Australian gold mining operation is firstly delineated, in terms of representative ore types and typical crushing and milling tasks. Then some of the technical and economic basics related to fine crushing are re-examined, including: energy relationships in crushing and milling; concepts of reduction ratio; recirculating load controversies; and questions of realistic economics in crushing gold ores. The economics of the typical gold mining operation are shown to be rather marginal; not the lavish "bonanza" many may imagine. Likewise, crushing cost expectations are frequently quite Unrealistic.

Jan 1, 1987

By R. A. H. Lycett, P. R. Jochens, D. D. Howat

The crystallization of rutile from titaniferous slags by R. A. H. LYCETT, M.Se. (Eng.),"A.M.I.M.M. (Visitor), P. R. JOCHENS, Pr. Eng., M.Se. (Eng.) (Rand), Ph.D. (Member), and D. D. HOWAT, B.Se., Ph.D., F.R.I.C., F.I.M. (Fellow) Factors affecting the precipitation of rutile from smelter slags were investigated, with particular reference to the effect of additions of phosphorus pentoxide to the slag. The phases were identified and the phase boundaries determined for slags having phosphorus pentoxide additions of 0 to 50 per cent. The liquidus temperatures of these slags were determined, and a pseudo-binary phase diagram was constructed. Rutile crystallized as the primary phase from melts having a phosphorus pentoxide content of more than IS,S per cent. Prismatic rutile crystals whose TiO. content was more than 97 per cent were grown from melts that had a phosphorus pentoxide addition of 30 per cent. However, the morphology of the precipitated rutile was such as to make subsequent separation impracticable.

Jan 9, 1975

February 18th, 1873. THE Institute assembled in the Hall of the Boston Natural History Society on Tuesday evening. Dr. T. Sterry Hunt, of the Boston Institute of Technology, after a brief address of welcome to the Institute, read an introductory paper on the Geognostical History of the Metals. President Raymond responded to the welcome of Dr. Hunt. The following names were then presented to the Institute, with the recommendation of the Council, for election Adams, J. M., - Silver City, Idaho. Daggett, Ellsworth, - Salt Lake City, Utah. Geist, Alfred W., - Boston, Mass. Hays, Dr. S. Dana, - Boston, Mass. Heinrich, Oswald J., - Midlothian, Va. Johnson, J., - Braidwood, Ill. Leckie, Robert G., - Actonvale, Canada. Lyman, Edward, - Troy, N. Y. Maltby, William, - Braidwood, Ill. Nichols, Lyman, Jr., - Boston, Mass. Ordway, Prof. J. M., - Boston, Mass. Rand, Theodore D., - Philadelphia, Pa. Richards, Prof. Robert H., - Boston, Mass. Rockwell, Prof. Alfred P., - Boston, Mass. Roepper, Charles W., - Bethlehem, Pa. Schulz, A. von, - Central City, Colorado. Singer, William F., - Pittsburgh, Pa. Spillsbury, E. G., - New York. Wells, Calvin, - Pittsburgh, Pa. The session concluded with the reading and discussion of a paper, by Henry Engelmann, On the Mines and Ores of the Little Cottonwood Canyon, Utah. The second session was held on Wednesday morning, when the following papers were presented; On the Midlothian Coal Mines, by Oswald J. Heinrich. On the Probable Existence of Microscopic Diamonds in California, by Prof. Benjamin Silliman.

Jan 1, 1873

By James R. Boyle

The value of Alabama's nonfuel mineral production in 1978 and 1979 was 8831.8 million and $336.4 million, respectively. In 1978, nearly all commodities registered an increase in production and value; unit value increased for all commodities, with the exception of native asphalt and sand and gravel. Alabama led the Nation in the production of crushed marble and was second in bauxite, third in masonry cement, kaolin, native asphalt, and oyster shell, and fourth in bentonite, dimension marble, fire clay, and scrap mica. Trend; and Developments.-The Alabama State Docks at the Port of Mobile handled more than 10 million tons of bulk material in fiscal year 1978; volume dropped slightly to 9.8 million tons in fiscal 1979. Bulk materials comprise the major activity at the facility, with iron ore and bauxite being two of the major materials handled. The movement of these ores is vital to the operation of many heavy industries in the State.

Jan 1, 1981

By Robert A. Gault, T. Scott Ercit, Mehmet F. Taner

"Abstract -Vanadium mineralization occurs in oxide-rich horizons within the layered gabbro zones of the upper parts of the Bell River Complex, Matagami, Québec and the Lac Doré Complex, Chibougamau, Québec. The vanadium-rich horizons are well defined on the ground and in aeromagnetic surveys by their high magnetic susceptibility; consequently, magnetic susceptibility can be an indicator of vanadium mineralization. The main oxide minerals are ilmenite and titanian magnetite, containing 20% to 70% of volume and the ratio of titanian magnetite to ilmenite is relatively constant, ranging from about 1:1 to 2:1. Their sizes are less than 5 µm to greater than 1 mm to 2 mm, occurring as coarse- to medium-grained subhedral crystals intergrown with cumulate silicate minerals (plagioclase, pyroxene, etc.). Electron microprobe analyses indicate that the ilmenite grains are mineralogically and compositionally homogeneous and have low V contents (average 0.18% equivalent V2O5). In contrast, the titanian magnetite grains are inhomogeneous, consisting of trellisworks of ilmenite lamellae in Ti-poor, V-rich magnetite [less than 2 wt% TiO2, and 1.41% equiv. V2O5 (1.16% V2O3) for 20 analyses]. Thus, the magnetite is the principal ore mineral of vanadium; it hosts vanadium in the form of V3+, not V5+, as is commonly and erroneously reported. We have also devised a flowchart for the beneficiation of vanadium-titanium ores. Sommaire - La minéralisation de vanadium se trouve dans des horizons riches en minéraux oxydés de la partie supérieure des zones de gabbros lités des Complexes de la Rivière Bell, Matagami, Québec et du Lac Doré, Chibougamau, Québec. Des horizons riches en vanadium ont été bien définis sur le terrain et dans les levés aéromagnétiques par leur susceptibilité magnétique élevée; conséquemment, la susceptibilité magnétique est l’indicateur directe du contenu en vanadium. Les principaux minéraux oxydés sont l’ilménite et la magnétite titanifère, contenant 20% à 70% du volume et le rapport de magnétite titanifère à ilménite est relativement constant, allant d’environ 1:1 à 2:1. Leur dimension varie de 5 µm à plus grande que 1 mm à 2 mm, apparaissant sous forme de cristaux subidiomorphes, de grains grossiers à médiums, intercroissant avec la gangue silicatée (plagioclase, pyroxène, etc.) de la texture de cumulat. Les analyses à la microsonde électronique montrent que les grains d’ilménite sont minéralogiquement et chimiquement homogènes avec un faible contenu en V (moyenne 0.18% équiv. V2O5 ). Contrairement, les grains de magnétite titanifère sont hétérogènes, contenant des lamelles d’ilménite en "trellisworks"; ces grains sont pauvres en Ti et riches en V pour la portion magnétite de la magnétite titanifère [surtout contenant moins de 2 wt. % TiO2, et en moyenne 1.41% équiv. (1.16% V2O3) pour 20 analyses]. Ainsi, la magnétite est le principal minerai de vanadium; elle renferme du vanadium sous forme de V3+ et non de V5+, tel qu’il a été communément et à tort rapporté. Nous avons aussi défini un "flowchart" pour la bénéficiation des minerais de vanadium-titanium."

Jan 1, 1998