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By Robin P. Gardner

A radioisotope tracer method combined with a suitable back-calculation method is proposed and evaluated for the determination of model simulation parameters in open-circuit continuous ball mills. The method essentially consists of using impulse and/or step injections of short-lived radioisotopes of the naturally occurring trace elements manganese and sodium. It is evaluated here on the basis of the minimum standard deviations of the product weight-size distributions. These minimum standard deviations are taken as those predicted by a Poisson distribution of the number of particles present in size fractions of the samples taken for analysis. Previously developed tanks-in-series lumped parameter models are used in the evaluation. The results indicate that the method is very promising.

Jan 1, 1976

By R. F. Frantz, T. P. McNulty

The upper-level mineralization of the din Buttes, Arizona copper orebody consists primarily of dilute copper silicate impregnation in fault clay and throughout the altered limestone hostrock. Cuprite and native copper are minor with true chrysocolla rare. Owing to the high calcium carbonate and to the hydrogen ion exchange capacity of the clays, acid leaching would be economical only with cheap acid available. Leaching of the silicate copper with reagents other than sulfuric acid is slow and incomplete unless the ore is first heated to disorder the mineralized grains and to reduce partially the contained copper. Following heat treatment, 70 to 90 percent of the nonsulfide copper can be dissolved in aqueous anrmonium carbonate. Recovery of a pregnant solution by counter-current decantation is effective provided ammonium carbonate solution is added to the washing stages in order to oppose adsorption of dissolved copper by clays in the residue. Thermal stripping of the pregnant solution permits recovery of ammonia and carbon dioxide while precipitating copper either as oxide or carbonate. The research program was carried from batch tests through continuous miniplant operation to a five-month campaign in a 20 TPD continuous pilot plant. Pilot plant results, the relationships among key varibles, and a detailed flowsheet are given.

Jan 1, 1973

By M. A. Olade

Biotite, magnetite and quartz feldspar separates from rocks around porphyry copper deposits in the Highland Valley have been analyzed for copper, zinc and other related trace and major elements. Results show high copper concentrations in mineral samples close to mineralization, with a strong positive correlation with whole-rock copper contents. Zinc, on the other hand, shows no cleat-cut systematic relationship to mineralization, although there is a subtle decrease in the dues obtained for anomalous biotite samples. Manganese, cobalt and nickel in biotites show similar patterns as zinc. Using a sulfide-selective leach, it is show that the enhanced copper dues in mineral samples proximate to mineralization can be accounted for by the presence of minute inclusions of sulfides. In contrast zinc seems to occur in isomorphous substitution for femic elements, in a form that is leachable by hydrothermal activity. Results also show that copper content of biotite has a positive correlation with the modal proportion of biotites and their iron contents, whereas a negative relationship with manganese is apparent Geochemical contrast for copper between background and anomaly is not better in mineral fractions than whole rocks, consequently the use of minerals as sampling media shows no obvious advantage for mineral exploration purposes in the Highland Valley district.

Jan 9, 1979

By Clemens Jones

An interesting paper by J. E. Merion and Edward Hart, in Volume I., No. 2, of the Journal of Analytical Chemistry, on the Decomposition of Blast-Furnace Cinder by Acid, describes a plan of sampling the cinder by means of a previously-heated iron bar thrust into the cinder car or into the cinder at the notch, and then allowed to cool, thus chilling the cinder which adheres to the bar, and rendering it decomposable by hydrochloric acid, of 1.12 sp. gr. A short series of results is given, from which the deduction follows that blast-furnace cinder " is decomposed perfectly when chilled." Where many silica determinations are to be made, this method, if reliable, would effect notable economy of time and reagents. The conversion of insoluble silicates by fusion with an alkaline carbonate, together with the subsequent solution, evaporation, drying, etc., is destined to remain the standard method. But all fusionmethods are time-consuming and expensive. Chilling appears to render the supplementary method available for all practical purposes, in the determination of silica in cinder. But, with a view of securing more evidence on the subject, and in view of the fact that uniform results were not obtained by employing this method, it was decided to test the method in the laboratory of the Thomas Iron Company where a large number of silica determinations are made. The experience met with may not be devoid of value, both theoretical and practical. Mr. Iles's paper, in the Chemical News, Volume L., 1881, doubtless suggested to several chemists, connected with iron metallurgical

Jan 1, 1888

By Chester Washburne

AT present it is impossible to estimate closely the amount of oil obtainable from a given area of land. However, after the completion of a few properly distributed prospect wells, one can calculate the approximate yield of the sands penetrated, with a probable error of say 50 per cent. Even rough predictions of this kind are of value in, large operations. Without wells upon it, one can never be absolutely certain that an area will produce any oil whatever, and one can only indulge in wild guesses of the probable productive area, before the geological structure has been carefully contoured and the top of the basal water plotted on a map. This requires wells. At times it is desirable to form an idea of the possible yield of oil in advance of drilling, as in cases where the price asked for undeveloped land seems too high, but where the probability of finding oil is furnished by neighboring development, supported by the geology. In such cases the most one can do is to make an estimate of possible maximum yield, which may of course far exceed results, and which is of use mainly in the prevention of excessive initial investment. The method is very significant in a general way, as in regions like the Bighorn Basin, Wyoming, where the productive sands in the Cretaceous shale are so few and so thin and fine that they cannot develop very great production, although the high quality of the oil probably will counterbalance this defect sufficiently to give local profit in favorable areas. Reservoir Capacity of Sands.-The porosity of a stratum is the measure of its maximum reservoir capacity for liquids and gases. The porosity may be determined experimentally and must be used in connection with the total volume of the sand.

Jan 2, 1915

By M. J. Duggin

Evidence is produced below to show that the carbide "Mn,C," reported by Kw,and ersson' is really a mixture of two carbides. One is an Fe-Mn carbide which is probably isomorphous with hexagonal Mn15C4, reported by Bouchand and Pruchart.' The othev is a tetragonul Fe-Mn carbide with cell dzmensions close to those reported previously by the author3 for an Fe0.1Mno. carbide. IN a recent investigation several Fe-Mn carbide specimens, each weighing about 5 g, were prepared in a manner previously reported.3 Debye-Scherrer X-ray photographs were taken of at least two samples from different parts of each specimen using a 114.6-mm-diam camera. The exposure time was 2 hr using filtered chromium radiation, a tube voltage of 35 kv and a tube current of 10 ma. In the case of one specimen, which contained nominal weight percentages of iron, manganese, and carbon of 9.40, 84. 6,, and 6.0, respectively, duplicate chemical analyses indicated f1.2 and 5.5 wt pct C to be present in the two samples taken of the specimen: no graphitic carbon was detected. One powder-diffraction pattern of this specimen indicated the presence of the tetragons: carbide reported earlier,3 (a = 6.772A, c = 9.427A), plus cementite (O), plus an unknown structure. The second powder-

Jan 1, 1970

By G. Ferrara

In process and plant simulation, more reliable prediction of industrial results and evaluation of data for designing purposes may be attained by the combined use of (a) modeling and simulation of ore characteristics and (b) modeling and simulation of integrated plant operations. The systems for modeling and simulation of ore characteristics are discussed as well as the conditions in which their use may be necessary (complex structure of the ore-body and variability of the ore fed to the plant). Two examples, for coal and bauxite run-of-mine (ROM), are reported. The procedure of linking the process unit models and the approaches for the solution of integrated systems are indicated. A general-purpose program for the simulation of integrated plant operations is described, and some examples of its use are reported.

Jan 1, 1984

By D. Harrington

TheRe has been, during the past year, a wealth of report data and discussion relating directly or indirectly to various phases of ventilation of metal mines, and many of the data are from foreign sources. The phase of the subject most generously accorded the attention of the technical press is that of cooling mine air, with much less attention to other fairly intimately associated features such as fan performance, friction factors, fires, mine gases, mine lighting, health of miners, and ventilation standards. Cooling Mine Air South Africa, with its very deep mining on the Rand and with fairly high working temperatures, 'contributes the most definite data on the subject of cooling mine air, and undoubtedly the most interesting issued are those from a paper by J. H. Dobson,' in which he gives a comprehensive review of the subject as gleaned largely by analyzing the data in three papers.2 Dr. Dobson's summation is decidedly interesting. In general it is recognized that the introducing into the mine and circulating to the working places of large volumes of pure air is the most effective method of giving deep, hot metal-mine workings reasonably efficient working conditions. A tabulation as to the cost of securing various amounts of cooling by circulating various volumes, from 230,000 to 760,000 cu. ft. per min., indicates that there are cost limits beyond which increase of quantity of air in circulation is impracticable, as the annual cost of circulating 230,000 cu. ft. of air per min. in a certain mine at a depth of

Jan 1, 1928

John Eliot Allen has been made acting head, dept. of geology, New Mexico Institute of Mining and Technology, Socorro, N. Mex. He had been associate professor of geology. Robert B. Anderson has accepted a position with the U. S. Steel Co., Gary, W. Va., as assistant to the superintendent, No. 2 mine. [ ] Donald L. Archibald has joined the sales dept. of the Ellicott Machine Corp., Baltimore. He formerly had been associated with the Joy Mfg. Co., St. Louis. J. C. Boswell has been appointed manager of the Fairbanks dept., United Smelting Refining & Mining Co. J. B. Metcalfe has been appointed assistant to the president. G. Howard LeFevre was elected vice-president and general manager of metal sales and R. N. Hunt, vice-president and chief geologist was elected a director. R. B. Earling, vice-president and general manager of Alaskan operations, has retired but. will con¬tinue to serve on the board of directors. J. D. Crawford has been appointed general manager of Alaskan operations.

Jan 1, 1952

By Sooi P. Chong

Expansion of concentrator capacity at Iron Ore Company of Canada's Carol Lake plant resulted in a dramatic increase in the production of fines. With iron recovery from the fines running only 18%, Carol Lake engineers initiated an extensive test program which resulted in the installation in July 1977, of a full-scale plant utilizing Reichert cone concentrators. Results to date have indicated a 100% increase in iron recovery from the concentrator's fines product. Carol Lake is located near the western boundary of Labrador, Newfoundland, some 960 km (600 mi) northeast of Montreal. Concentrator operations began in 1962 with a design capacity of 7 million t/y (7.7 million stpy). The bulk of the concentrate was pelletized at a 6 million t/y (6.6 million stpy) pelletizing plant completed in 1963. The remaining concentrate was sold in the international market. The concentrator was first expanded in 1966 to 10 million t/y (11 million stpy) capacity. In 1967, the pellet plant was expanded to match the increase in concentrate production. Sales increases led to a further expansion in 1973. By 1977, more than 40 million tons (44 million st) of crude ore were processed to recover in excess of 17.42 million tons (19 million st) of concentrate and 10.4 million tons (11.5 million st) of pellets.

Jan 12, 1978

Calendar of Events

Jan 11, 1961

By Osamu Fukuta

The geological and geochemical characteristics of the Japanese iodine-rich brines are outlined. The iodine-rich brine in Japan is primary in its origin and its occurrence is limited in the younger marine sediments. The iodine-rich subsurface water is saturated or over- saturated by natural gas, but the water saturated by natural gas is not always rich in iodine. The iodide and bromide contents decrease with time. The bromide content decreases much more rapidly than that of iodide. It should be emphasized that the genetic environment of the Japanese type of dissolved gas and iodine deposit is not peculiar to the Japanese islands.

Jan 1, 1985

By John Patek

KNOWLEDGE of the relative floatability of silicate minerals is increas-ing in importance as flotation is being applied to the concentration of nonsulfides. Many silicates are in themselves commercial products amenable to concentration by flotation. Moreover, the selective flota-tion of other nonsulfide minerals, such as cassiterite, depends largely upon the floatability of associated. gangue silicates. Differences in floatability existing between the various silicates have not been suffi-ciently appreciated; for example, the feldspars that differ greatly in floatability have generally been merely treated as "feldspar." It was the purpose of the work described in this paper to determine by experi-ment the differences in floatability between silicates; to investigate the causes for such differences, and to discover a means of predetermining approximate floatability without the necessity of experimentation.

Jan 1, 1934

The Library of the above-named Societies is open from 9 A.M. to 10 P.M. on all week-days, except holidays, from September 1 to June 30, and from 9 A.M. to 6 P.M. during July and August. The Library contains about 55,000 volumes, including sets of technical periodicals and the publications of scientific and technical societies. Members of the Institute, with few exceptions, are forced to spend a portion of their time in localities isolated from sources of information. To these the Library can render valuable service through correspondence; letters requesting information will receive special attention. The Library is prepared to furnish references and copies of articles mining and metallurgical subjects; to determine the existence of mining maps, and to furnish general information as to the geology and mineral resources of all countries. All communications should be made as definite as possible so that the information received may be what is desired and not include collateral matter which may not be of interest. The time spent in searching for such collateral matter will be saved, and the information will be sent more promptly and in more usable shape. The members of the Institute can be of service to the Library by forwarding copies of mining reports, maps privately issued, and similar material, which will be classified, indexed, and made available to other members. Suggestions for additions to the Library, either by purchase or personal solicitation as gifts, will be welcomed. It is hoped that members while in the city will use the Library freely, and assurance is given that most careful service will be rendered to them.

Jan 4, 1915

By M. G. F. Sohnlein

IN a Bolivian tin concentrator an appliance was needed to furnish a suitable product for fine jigging from a pulp of the following composition: Mesh Per Cent. +20 8.0 +40 36.5 +60 9.0 +80 10.5 +100 5.5 +150 4.51 -150 25.0 99.0 Loss 1.0 IN the jigging process, particles of cassiterite as small as 0.1 mm. can be recovered, provided they are not present in excess, that is if the material treated on the jigs contains sufficient coarser sands to keep the interstices between the grains open. Removing the fine material from the pulp by screening, to prepare the jig feed, is impractical, because that means the use of an 80-mesh screen or finer, and is not as effective as hydraulic classification. A screen would eliminate mineral grains from the feed which can be recovered by jigging, and in addition would throw more gangue and low-grade middling on to the jig. Formerly a one-spigot Richards vortex classifier had been used to accomplish this separation, but the tangential openings through which the hydraulic water enters became clogged by fine vegetal matter with which the water was contaminated, and which it was impossible to remove from the water. Consequently the work of the classifier was imperfect and a good deal of slime was sent to the jig. When designing the plant referred to in this paper it was decided to use a hydraulic classifier as shown in Fig. 1. The essential features had been copied from the Anaconda classifier.1 This remodeled classifier consists of a truncated pyramidal wooden hooper A with an attachment of cast iron

Jan 4, 1916

By William L. Grube

PECIMEN preparation for electron metallography involves several steps, such as polishing, etching, replicating, mounting, and shadowing. Although each step must be done with care, the operation requiring the utmost attention is etching. Proper etching is important because the relief pattern developed on the surface of the specimen by the etchant, and reproduced as minute differences in thickness of the replica, determines entirely the amount of detail seen in the final micrograph. The characteristic colored stains, sometimes used in light metallography to simplify identification of certain microconstituents, cannot be tolerated because there is danger of introducing artifacts in the replicating operation. It is also quite difficult to remove plastic replicas from stained specimens. A suitable etchant for electron metallography must, therefore, in all cases exhibit a preferential attack upon each of the microconstituents present sufficient to result in a difference in surface elevation. When only two microconstituents are present, it is not too difficult to find a suitable etchant since their physical or chemical properties are generally sufficiently different to result in a marked difference in attack by the etchant. For example, picral (a saturated solution of picric acid in methanol used as an immersion etch) is a satisfactory etchant for the specimen shown in Fig. 1 consisting of iron carbide particles embedded in a ferrite matrix.'

Jan 1, 1952

By Augustus Locke, Edward H. Perry

In the exploration of a copper deposit by drilling, obvious advantages are to be gained from a distinction between primary and secondary ore.' Perhaps the chief of these is the aid which such a distinction renders in determining where a given hole should stop. The copper assay, often a sufficient guide, cannot always be exclusively relied upon. Primary ores may extend downward indefinitely and may fluctuate in value independently of depth: if primary ores are consistently lean for a considerable vertical distance, there is little reason to expect that, still deeper, they will increase to the commercial grade; on the other hand, rich primary ores may persist uninterruptedly downward or may come in again below a lean interval. Secondary ores, however, have a comparatively limited vertical extent; in a large way enrichment decreases with depth and finally gives out. It follows then, that when a hole descends from profitable ore into ore of less than the commercial minimum, the practical significance of the situation depends upon whether this decrease results from a decrease in secondary enrichment or is a variation in primary content: if the copper of the ore passed through has been chiefly secondary, little is gained in the average case by extending the hole much below the point at which the commercial limit is reached; but, when copper is chiefly primary, due weight must be given to the possibility that, still deeper, the ore may again improve. The distinction between primary and secondary ore may of course be effected through an examination of the drillings. It has been found, however, to be facilitated by curves made by plotting assays against

Jan 1, 1916

By Glenn Alvey

THE measure of value of an oil property is approximated by the length of time it takes to "pay out;" viz., the time required for it to return the original investment. This time varies in different fields. In the Appalachian and Mid-Continent fields, a good investment pays out in about four years; in California, it requires a slightly longer time; and in the Gulf field about two years. The two principal methods for establishing these values are based on acreage, as in California, and on production, as in the Appalachian field. The method of establishing values based on production1 was worked out in the Appalachian fields and approximates the value remarkably well in some fields; but it is a rule of thumb and should be used intelligently. Briefly, the method is as follows: An arbitrary number of dollars (called the barrel-day price) multiplied by the number of barrels of settled daily production of the property gives the value.. In its crudest application, the barrel-day price is determined by the "$10 to $.01" rule, which means that the barrel-day price is one thousand times the prevailing price of oil. For instance, with oil at $3.50 per bbl. the barrel-day price would be $3500 per bbl. This rule, however, is not strictly applied, for the, barrel price is varied according to whether or not the wells "hold up." But when a barrel price for a district has been fixed it is quite general to raise or lower the price with the fluctuation in the price of oil; here the" $10 to $.01" rule is used extensively. However, the prospective purchaser takes into account tangible equipment upon the property, the extent to which the drilling program has been carried out, whether or not the wells are "shot" or natural, depth of wells, spacing of wells, paraffin trouble, etc.

Jan 1, 1921

By E. J. Fasiska, L. Zwell

PREVIOUS investigations 1,2 of Fe3P described by pearson3 and schubert4 show that Fe3P has a bct unit cell having four Fe3P tetrahedra centered around each lattice point. The space group is 14, No. 82, and all atoms occupy general positions 8(g). The cell dimensions3 are: a = 9.090, c = 4.446 kX, with an axial ratio of c/o = 0.4891. We have measured the lattice parameters of Fe3P, using a Fe as an internal temperature standard, at 23°, 414°, and 678°C and computed the thermal expansion over this temperature range. The Fe,P was prepared by melting under vacuum (after flushing with argon) a commercially pure iron and "ferrophosphor" in a high-frequency induction furnace. Part of the ingot was crushed for X-ray examination and for chemical analysis. X-ray diffraction and light microscopy indicated iron phosphide (Fe3P) present as the major constituent and a small amount (about 5 pct) of a Fe. Chemical analysis showed 0.05 wt pct Si, 0.008 wt pct N, 0.018 wt pet C, and less than 0.02 wt pct each of other metallic elements. X-ray diffraction powder patterns were obtained from a mixture of iron and Fe3P sealed in an evacuated quartz capsule using a Unicam high-temperature

Jan 1, 1968

By S. E. Piper, E. M. Buchalter, R. P. King, E. T. Woodburn

The problems involved in an optimum decision making model for flotation circuit are, first of all, to characterize the feed material in terms of parameters which can quantitatively describe the network flotation action in terms of a feasible set of control actions. Once the characterization has been postulated, it is then necessary to devise tests relating to parameter sensitivity, in order that credibility of the model predictions can be assessed. Once a credible model is available, the optimum control set is determined by a hill climbing technique. Details will be reported as to the credibility of model predictions using the stochastic flotation model on a network and further, computational problems associated with hill climbing for a complex objective function are reviewed. Discussion is presented on use of the Rosenbrock technique with constraints and use of a modified objective function with constrained derivatives when employing Fletcher and Powell technique.

Jan 1, 1969