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By Ernest Wiltsee

The Half-Moon mine, situated three miles west of the town of Pioche, exhibits geological features which are peculiar and interesting. The general formation in the vicinity of Pioche consists of a quartzite, usually covered with an overlying limestone containing strata of shale. In the camp itself, where the original mines are situated, the quartzite has been denuded, and the principal veins outcrop in this formation; to the west, the quartzite is again covered with limestone, containing thin strata of shale.

Jan 1, 1893

[ PRESIDENTS DAVID THOMAS 1871 'R. W. RAYMOND 1872-1874 'A L. HOLLEY 1875 'ABRAM S. HEWITT 1876 'T. STERRY HUNT 1877 'ECKLEY B. COXE 1878-1879 'WILLIAM P. SHINNY 1880 'WILLIAM METCALF 1881 'RICHARD P. ROTHWELL 1882 'ROBERT W. HUNT 1883 'JAMES C. BAYLES 1884-1885 ROBERT H. RICHARDS 1886 'THOMAS EGLESTON 1887 'WILLIAM B. POTTER 1888 'RICHARD PEARCE 1889 'ABRAM S. HEWITT 1890 'JOHN BIRKINBINE 1891-1892 'H. M. Hows 1893 'JOHN FRITZ 1894 'J. D. WEEKS 1895 'E. G. SPILSBURY 1896 'THOMAS M. DROWN 1897 'CHARLES KIRCHHOFF 1898 'JAMES DOUGLAS 1899-1900 'E. E. OLCOTT 1901-1902 'ALBERT R. LEDOUX 1903 'JAMES GAYLEY 1904-1905 'ROBERT W. HUNT 1906 'JOHN HAYS HAMMOND 1907-1908 'D. W. BRUNTON 1909-1910 'CHARLES KIRCHHOFF 1911]

Jan 1, 1940

By George Hale

(The following extracts from Mr. Hale's paper have been made by the Editor, as being of particular interest to our members.) In an address delivered on May 28, at the kind invitation of the Engineering Foundation, I briefly sketched "The War Activities of the National Research Council. "' The wide scope of my subject forced me to touch very lightly upon engineering; I therefore beg permission to return to this phase of the subject. As shown in my earlier address, the' charter membership of the National Academy of Sciences, organized in the midst of the Civil War,

Jan 10, 1918

By K. A. Natarajan, I. Iwasaki

The influence of dissolved oxygen and the Pt - Pt-O reaction on the measurement of redox potentials in solutions containing ferrous-ferric couple was examined. Current-potential curves were used to illustrate the shift in measured potentials toward the oxygen potential in oxygenated and deoxygenated systems at low concentrations of ferrous and ferric ions. The ranges of concentrations of the ferrous-ferric couple, in which the interference from oxygen and the platinum-oxygen reactions becomes significant, are illustrated through the mixed potential mechanism.

Jan 1, 1975

By T. F. Petty

During 1935 there were drilled in North Central Texas 1071 wells, of which 565 were dry holes, 469 were oil wells with an initial production of 43,766 bbl. and 37 were gas wells with an initial production of 129,332,000 cu. ft. Production has been 14,180,042 bbl., or a daily average of 38,849 bbl. In Table 1 are listed the various pools of the district. Most of the smaller pools are of minor importance and are merely productive spots. Numerous other similar spots might have been listed as pools but their production is included in other fields. There are a few flowing wells but practically all of the wells are being pumped. The estimated potential is about 50,000 bbl. and the allowable production is based on the Texas Marginal Well Law. In Table 2, wildcat wells that have resulted in the discovery of pools or important extensions to old pools or that have contributed to the geological information of the area are listed.

Jan 1, 1936

By Joseph Bernhardt

Use of concrete underground at No. 4 mine, Cornwall, Pa., has become increasingly important. Starting with small amounts at finger openings, occasional raises, piers, its use has expanded to entire slushing drifts and haulages. Besides eliminating costly timber repairs, concreting costs of slushing drifts have proved cheaper than timbering. Higher haulage-concreting costs are offset by no maintenance charges during the life of the haulage.

Jan 3, 1950

By William Hamilton Merritt

At the Atlanta Meeting in October, 1895, a short paper was presented by Mr. R. W. Leonard on the " Assay of Auriferous Ores and Gravels by Amalgamation and the Blow-pipe" (Trans., xxv., 645), embodying the results of some very conclusive tests as to the value of the process. His arguments regarding the desirability of the process appear to be indisputable, but the practicability of the field-outfit used by him is open to question. The Province of Ontario, in which Kingston is situated, is still largely unexplored; and at the Kingstoil School of Mining we give much attention to the instruction of prospectors and the testing of ores. To this end, not only is there a small mill (to which Mr. Leonard alludes) attached to the school, but prospectors' classes

Jan 1, 1897

By R. Malmstrom, H. Heden, K. Likin

Sublevel caving techniques at Luossavaara-Kiirunavaara AB (LKAB) in Sweden have undergone significant modification over the years as management strives to maintain mine viability amidst rising costs and erratic iron ore prices. LKAB, which is 96% state-owned, is Sweden's principal iron ore producer and operates three iron mines north of the Arctic Circle. By far, the largest of LKAB operations is the Kiirunavaara (Kiruna) underground iron mine which extracts an estimated 30 million t/y of ore, Other iron mines include the Malmberget underground nine, rated at 12 million t/y of ore, and the Svappavaara open-pit mine, rated at about 4.5 million t/y. Mined ores from Kiirunavaara and Svappavaara are shipped by rail to the northwestern harbor of Narvik, while Malmberget ores are sent to Lulea, located to the southeast. LKAB iron ores are marketed by Malmexport AB, which is owned jointly by LKAB and Granges, Sweden's base metal producer.

Jan 10, 1979

By T. F. Petty

During 1935 there were drilled in North Central Texas 1071 wells, of which 565 were dry holes, 469 were oil wells with an initial production of 43,766 bbl. and 37 were gas wells with an initial production of 129,332,000 cu. ft. Production has been 14,180,042 bbl., or a daily average of 38,849 bbl. In Table 1 are listed the various pools of the district. Most of the smaller pools are of minor importance and are merely productive spots. Numerous other similar spots might have been listed as pools but their production is included in other fields. There are a few flowing wells but practically all of the wells are being pumped. The estimated potential is about 50,000 bbl. and the allowable production is based on the Texas Marginal Well Law. In Table 2, wildcat wells that have resulted in the discovery of pools or important extensions to old pools or that have contributed to the geological information of the area are listed.

Jan 1, 1936

By J. D. Bateman

At Giant Yellowknife, where high grade gold-bearing orebodies are highly irregular in shape, geology has been applied extensively to the mining of ore. The classical functions of the mine geologist in the fields of exploration and mine development have been extended to guide ore extraction, ensuring "clean" mining and effectively reducing waste dilution.

Jan 12, 1951

By D. F. Kelsall

During the past twenty years, and especially in the last decade, hydraulic cyclones have found increasing application in metallurgical processing as classifiers and, under special circumstances, as thickeners. To a more limited extent cyclones have been used to extend heavy, or dense, medium separation into the finer size ranges, and several attempts have been made to separate dispersions of immiscible liquids with a view to use in the field of liquid- liquid extraction. Before considering several aspects of conventional application, less conventional applications and some potential uses of modified cyclones, the mechanism of separation within a cyclone and the effect of the, major variables will he summarized.

Jan 10, 1963

By M. J. Langley

Zinc ores were first discovered in Tennessee in 1856 at Jefferson City where a deposit became the Mossy Creek mine. From that time until 1913, small- scale attempts at prospecting and mining were made in various parts of the district. The actual systematic development of the zinc deposit dates from 1913 when the American Zinc Co. started operations at Mascot. Mining in the Mascot-Jefferson City area today is devoted exclusively to the zinc sulfide, sphalerite. Various grades of zinc mineralization have been found intermittently through a 600-ft vertical thickness. However, the commercial ore is confined to a total thickness of about 250 ft, from which it usually is mined irregularly from four or five separate levels known locally as "ore runs." In a few places vertical thicknesses up to 150 ft have been mined where commercial material extended from one run to another.

Jan 10, 1962

Elected Died 1895 *ABBOTT, AI ATTHUR 1908 1882 *ABBOTT, ARTHUR V 1906 1903 * ADAMS, CHARLES C. 1905 1884 *ADDY, MATTHEW 1896 1889 * AKERS, WILLIAMS 1906 1894 *ALLEN R B 1896 1905 * ALLEN, R. SCOTT 1906 1874 *AMIOT, H 1892 1886 *AMSLER, CARL 1894 1895 *ÅNGSTROM, CARL 1901 1900 * ARLETT, GEORGE H 1906 1895 *ARMSTRONG, JOHN F 1898 1882 *ARNOLDS, HUGO 1886 1875 *ASHBURNER, CHARLES A 1889 1872 *ASIIBURNER, WILLIAM 1887 1883 *ATKINS, C M , JR 1885 1905 * AUDTIN, PETER T 1907 1897 *AYERS, WILLIAM 1898 1885 *BABCOCK, GEO H 1893 1884 *BAILEY, EDWARD 1889 1880 *BAILEY, JACKSON 1887 1900 *BALLOU, FRANKLIN 1903

Jan 1, 1910

By S. R. Rao

Interaction of potassium amyl xanthate with pyrrhotite has been studied thermochemically. Heats of adsorption of xanthate on unactivated mineral and the mineral activated with cupric ions have been compared with heats of reactions between potassium amyl xanthate and ferrous and cupric salts. It is shown that xanthate is consumed by stoichiometric exchange with anions present at the mineral surface. The floatability of the unactivated mineral is poor since xanthate is precipitated in bulk without creating a hydrophobic surface on the mineral. At the activated mineral surface, xanthate is adsorbed in certain isolated patches (active spots) and thereby creates a hydrophobic surface. The hydrophobicity of the mineral is greatly improved by lowering the pH to 4.5.

Jan 1, 1972

By M. S. Azun

The article unfortunately has some serious flaws negating the usefulness of the paper. The authors claim that kriging (linear kriging) is superior to other methods such as polygon. This is not the case. The deterministic methods (referring to polygon, ID, IDS, etc.) should not be compared with the statistical methods (linear kriging, disjunctive kriging, etc.) because they differ not only in their assumptions, but also their tools used in estimation. Thus, they give different results. By comparing the results of deterministic methods and linear kriging, the authors conclude that polygon, IDS, and linear kriging give an average thickness close to the value obtained from realizations. Besides, they argue that linear kriging gives less variance than the others [(fig. 2)]. The first conclusion is expected, due to the well-known central limit theorem. The second is the result of the statistical properties of different estimators. Thus, the comparison presented in the paper is rather meaningless because the authors have failed to follow basic statistical procedures. The numerical results of different approaches to an estimation problem cannot be generalized. In conclusion, the paper is not a meaningful contribution, and sadly, quite erroneous.

Jan 1, 1985

By Donald W. Mitchell

MINE operators have a choice of several classifications of mechanical loaders. Within each classification there are many types and makes available. Table I lists loaders on which manufacturing data as to operating characteristics are available. This paper discusses the conditions met in a mine as they affect these characteristics. It is assumed that management will provide satisfactory engineering, supervision, power, maintenance, loader service within a concentration of workings, and a balanced working cycle served by balanced production equipment. These are factors which affect the optimum operational efficiency of a loader. The conditions which determine loader choice are:

Jan 5, 1951

By James E. Lawver

A SURVEY of Minerals Beneficiation Div. membership indicated genuine interest in automatic process control, but revealed that the average mill is operating with a minimum of self-regulating devices. Apparently, the mill operators are content to continue without controls until the practicality of self-regulating devices is more generally accepted, or, in the opinion of the writer, until automatic controls become a necessity to meet economic demands of product quality and cost. Both to stimulate interest in control, and to solicit publication of technical know-how by members and equipment manufacturers, this paper presents a cross section of control problems in two general categories: (a) Control problems that can usually be solved by reference to the literature, i.e. controls that have proven successful in the mineral or chemical industries; (b) Problems that are troublesome and frequently unsolved due to unavoidable adverse conditions in the mill circuit to be controlled.

Jan 10, 1953

By H. M. Morse

During the year of 1940, wildcat wells were drilled in 32 counties of Mississippi; 85 wells in all. These were scattered over the state from the most northern county to the southern counties and from the Mississippi River on the west to the Alabama line on the east. Yazoo County, with 19, received the largest number. The average depth of all the wells was 5333 ft. The shallowest well completed as a dry hole was in Yalobusha County, aban-doned at 1392 ft. in the Selma. The deepest well drilled was in Scott County, abandoned at 10,365 ft. in the Lower Cretaceous Paluxy. G. C. Grasty drilled the Kentucky Lumber Company No. I well, sec. 7, T. 10 S., R. 10 E., Itawamba County, to a depth of 3530 ft. and bottomed his hole in the Ordivician. Tinsley Oil Field.—In the Tinsley oil field 104 wells were completed as producers during 1940. Five producing sands have been logged with a total average thickness of I57 ft. of oil sand. One of these sands is in the Selma, three in the Eutaw, and one in the Tuscaloosa. Vaughan-Pickens Field.—The Vaughan-

Jan 1, 1941

By W. W. Simpson, W. L. Staker, R. G. Sandberg

The Bureau of Mines investigated selective extraction of Au and Ag from a low-grade Au ore containing Hg. Gold and silver were extracted from the ore in cyanide slurries, and Hg extraction was suppressed with sodium or calcium sulfide. Maximum Au extraction and minimum Hg extraction were obtained using solutions containing 17 kg NaCN/t of solution (0.34 lb NaCN/st). Increasing the cyanide concentration increased Hg extraction without increasing Au extraction. Mercury extraction from the ore was suppressed with 0.5-2.9 kg CaS/kg Hg (0.5-2.9 lb/lb) in the ore. Gold-to-mercury ratios of 100:1 to 400:1 were obtained in the leach solution, and on the activated carbon in a CIP circuit.

Jan 1, 1985

By Nicholas J. Grant, Chih-Chung Wang

TO phase of the Ti-0 system has the structure of NaCl and has a wide range of solid solubility.' In the course of studying the Ti-Cr-0 ternary system, binary alloys were made of iodide titanium and high purity TiO,. It was found from X-ray studies of the binary alloys that a transformation of the TiO appears to take place at a temperature near 925°C. Evidence of this phase change is best seen in Fig. 1. Fig. 1A shows the X-ray spectrometer pattern (CUKa radiation) of an alloy of 25 wt pct 0 corresponding to the stoichiometric composition of TiO.

Jan 1, 1957