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By Robert Ammon

THE milling practice at Mascot, at present, consists of dry crushing to 5/8 in., jigging, fine grinding, and flotation. The ore arrives at the mill from two mines, No. 1 mine shaft being located in the mill proper, and No. 2 mine shaft being situated about 2000 ft. east of the mill. No. 2 mine is served by a coarse-crushing plant and aerial tramway to the mill bins. In jigging the No. 2 mine ore, 50 per cent. of the mill feed is rejected by the jigs as a jig tailing ranging from 5/8 in. to 10 mesh; the balance of this ore, after removing a jig concentrate, is ground to flotation feed. In jigging No. 1 mine ore, approximately 80 per. cent. of the mill feed is rejected as a coarse jig tailing, and the balance is ground to flotation feed without the removal of a jig concentrate. The difference in the treatment is due to the fact that No. 2 mine ore carries a higher content of zinc than that from No. 1 mine. Of the total concentrates produced, 30 per cent. are made on jigs and 70 per cent. by flotation. At present, 1350 tons of No. 2 ore and 800 tons of No. 1 ore are treated each 24 hours. The recoveries for a typical week are as follows: Heads 3.55 Jig concentrates 61.30 Jig tails 0.80 Flotation concentrates 60.60 Flotation tails 0.09 Extraction 86.50 The associated minerals are a straw-colored sphalerite, dolomite, calcite, pyrite, quartz, and a small amount of greenockite, which occurs as a stain and sometimes small crystals along with sphalerite, but is comparatively rare. Pyrite is present in small quantities, usually less than 0.5 per cent.; quartz occurs in bands a few inches thick. A complete analysis of the ore is as follows:

Jan 9, 1924

By J. L. Bray

Lead has often been suggested as a protective coating for iron and steel. Such a protective coating should possess: (1) good adhesion, (2) durability, (3) ease of application, (4) freedom from pinholes, (5) good appearance and (6) low cost, but, unfortunately, lead coatings so far produced do not have all of these characteristics. Because of the necessity of carrying out the coating process cheaply, and because lead solutions have poor plating characteristics, most of the efforts have been directed toward the hot-dipping process rather than electroplating. The hot-dipping processes using lead have not been successful chiefly because of the lack of adherence between iron and lead. In any coating process involving iron a bond can be obtained only by the formation of an intermetallic compound, the formation of a solid solution, or mechanical means. Lead forms with iron two immiscible liquid solutions, and in the solid state no intermetallic compounds or solutions. It is necessary, therefore, to employ some other element or elements as a binding agent. Tin may be used as in terneplate, or copper in the form of a thin film of electrolytically deposited metal to which the lead will adhere. Because of its physical and chemical properties, lead as a coakkg medium would undoubtedly be limited in its use to sheet and wire and then only when the article is not subject to abrasion or wear. A very large tonnage of these products is being used under such conditions and a successful lead-coating process should be a valuable contribution to the science. Two other difficulties stand in the way of successful lead coating—that of poor appearance of the weathered surface and the tendency of the lead to form pinholes during solidification. Since lead is commonly accepted as cathodic to iron, these exposed areas are ones of accelerated corrosion. Use of Zinc.—The method under consideration involves zinc as a binding agent on both the steel sheet and in the molten bath. This

Jan 1, 1937

By Waldemar Lindgren

No one would maintain that all ore deposits or all deposits of useful minerals have been formed by the same processes. Generally they have originated by special processes of concentration but these may be of many different kinds. Some deposits have their origin in chemical or biochemical processes of concentration in rivers, lakes or seas, others developed on land by means of chemical reactions of surface waters on various forms of rocks. Certain insoluble substances remained behind; others were dissolved and precipitated in favorable places. This action proceeded in the realm of the oxidizing surface waters or in the deeper zones to which the waters from the surface could find their way. Examples of the latter kind may be found in the extensive copper and vanadium deposits of some sedimentary beds or in the lead and zinc deposits of certain broad limestone strata. In these instances the evidence for any other mode of origin would seem to be very weak indeed.' Nor does it seem possible to deny that circulating waters may form deposits of the more common metals along fissures after having dissolved many constituents from paths traversed. Another very large class has been formed by magnetic processes of concentration. The last 40 years have been a period of intense activity in the investigation and description of a vast number of deposits; all modern methods have been employed and the result is an accumulation of data, difficult or impossible to master. It has been a period similar to that in petrography. The generalizations, the able deductions, have lagged behind. Evidently several geologists have become weary of this "infinite detail" and a mistrust of the microscope seems to have arisen. Although this feeling of being swamped in microscopic detail is a painful experience, nevertheless only through the detail in combination with the large features, and only by utilizing all the related sciences shall we

Jan 1, 1927

By W. S. Ayres

By A. K. Sinha

The annual production and productivity of underground coal mines in recent years declined from 334 Mt (368 million st) and 14.5 t (16 st) per man per shift in 1969 to approximately 254 Mt (280 million st) and less than 8 t (9 st) per man per shift in 1977. Productivity is still hovering at about 7.25 t (8 st) per man per shift. According to US Bureau of Mines, the estimated US coal reserve is about 396 Gt (437 billion st), 68.65% of which is obtainable by underground mining methods. Approximately 153 Gt (169 billion st), or about 85.2% of the high Btu premium coking coal of the eastern US, would need to be extracted by underground mining methods. It is thus apparent that under- ground mining will continue to play a major role in total US coal production, which is expected to rapidly increase to about 1.1 Gt (1.2 billion st) by 1985, with about 606 Mt (668 million st) being contributed by underground mines. Production Potential of Continuous Mining The production potential of a continuous mining section depends primarily on the producing ability of the miner, transporting ability of the face haulage, and the matching of the two systems. The producing ability of the continuous miner depends on its actual cutting ability and the time available for cutting coal. The performance of 10 continuous miners operating in coal seams of various thicknesses were monitored in Pennsylvania and West Virginia, using continuous electrical power analyzers and time studies. The recordings on current and power strip charts yielded an accurate analysis of the cutting, trimming, and idle times of the machines on a full shift basis. Continuous miners of various models and sizes from 112-298 kW (150-400 hp) were monitored. Based on actual cutting time, the average cutting ability of the machines, as shown in [Fig. 1], ranged from

Jan 1, 1983

Connecticut Geological and Natural History Survey, P O Box 1106, New Haven, Conn W. E Britton, Superintendent. A complete list of Bulletins available will be sent upon request. Address all inquiries for publications to: George S Godard, State Librarian, Hartford, Conn Fifty-one Bulletins have been issued, 15 of which are of particular interest, dealing with the geology of the state, and are available as follows; 4, The clays and clay industries of Connecticut, by G. F Loughlin (1905), 35 cents; 8, Bibliography of Connecticut geology, by H E Gregory (1907), 20 cents, 13, The lithology of Connecticut, by J Barrell and G. F Loughlin (1910), 45 cents, 18, Triassic fishes of Connecticut, by C. R Eastman (1911), 30 cents, 23, Central Connecticut in the geologic past, by J. Barrell (1915), 20 cents, 24, Triassic life of the Connecticut Valley, by R Lull (1915), 70 cents, 29, The Quaternary geology of the New Haven region, Connecticut, by F. Ward (1920), 60 cents, 30, Drainage modifications, and glaciation in the Danbury region, Connecticut, by Ruth S. Harvey (1920), 55 cents, 33, Geology of the Stonington region, Connecticut, by L H. Martin (1925), 60 cents, 40, The geology of the Shepaug Aqueduct Tunnel, Litchfield County, Connecticut, by W M. Agar (1927), 50 cents; 41, Guide to the geology of Middletown, Connecticut, and Vicinity, by W. N Rice and W. G Foye (1927), $1, 44, Report on the water resources of Connecticut, by R. H Suttee (1928), $1, 46, The physical history of the Connecticut shoreline, by H S Sharp (1929), 75 cents; 47, The glacial geology of Connecticut, by R F. Flint (1929), $2, 51, Minerals of Connecticut, by J F Schairer (1932), 75 cents Bulletin 51 explains the physical and chemical properties of minerals, their classification, and describes more than 100 common minerals found in Connecticut. A bibliography is included The Survey gratuitously distributes all its Bulletins to state residents, scientific institutions, etc. Prices quoted are to private citizens of other states

Jan 1, 1933

G. M. TAYLOR,* Colorado Springs, Colo.-The ore treated at the United Eastern is primarily a gold one and is cyanided-the counter-current decantation method being employed. One of our employees visited this plant a few months ago and, on his return, reported that the moisture in the tailing was carrying 20 c. per ton, which would appear to be somewhat high. As this type of plant has been advocated by one of the recognized cyaniding engineering firms in the country, and a number of these plants are in successful operation, it does not seem to me that the dissolved loss could be so high, and I would like to know if any one can give any definite information on this point? J. V. N. DORR, New York, N. Y.-I am very glad that Mr. Taylor has raised this question. When I first read Mr. North's paper and saw his statement, that they had an actual dissolved loss of 21.5 c. per ton, I was very much puzzled at this high loss which appeared avoidable by another decantation or the addition of a rotary filter. Reading it again, however, I noted that the actual dissolved loss of 21.5 c. given was evi-dently obtained by multiplying the assay of solution discharged from Z. thickener by the tonnage. On the basis of 283 tons milled per clay, this means $56.54 going to the clam. He states, however, that he returns from. the dam into the system, 70 tons daily assaying 40 c. per ton or $28 per day, so it would seem reasonable, unless I have overlooked something to regard the actual dissolved loss as $56.54 less $28 or $28.54, equaling 10.8 c. per ton. Even this loss, however, is much higher than good practice elsewhere, and can be accounted for largely by the tonnage being handled, which I believe is 30 per cent. above the capacity planned.

Jan 12, 1919

By Arthur Notman

THE matters I had intended to present to you ap-peared in the March 12 issue of Engineering and Mining Journal over the signature of George J. Young, so that although I should like to talk to you for about three hours on this subject, unfortunately it has all been done before. The subject originally sug-gested to me was the trend in mining methods. You will find that fully set forth much more clearly than I could hope to do, in Mr. Young's article, so that I shall confine my attention to a few points of interest in specific cases. You are undoubtedly familiar with the problem that was presented to the Miami Copper Co. when they had exhausted their so-called high-grade orebody. They had what appeared to be a large tonnage of material which their preliminary development work and such drilling as was done indicated contained one per cent copper or a-little over, and how to mine that profitably by underground methods was the question. It was somewhat complicated by the fact that the nature of the ground made them doubtful of their ability to cave it successfully. It was unquestionably harder ground than that of the more highly mineralized sections of the Miami and Inspiration- ore zone which had been mined. However, they had kept very accurate and complete records of past accomplishments and knew what they had to work with and what modifications with respect to costs would be necessary in order to solve this problem. Under the old method of working, they were extract-ing about 71/2 tons per man employed in the mining department; that is to say all labor, direct and indirect required to put the ore in the mill bins, and this, with the grade of ore which they had, resulted in a satis-factory financial outcome. Under their modified method now in use, they have raised that output per man to 29 tons per man shift. That is almost four times what they were doing with the old method.

Jan 4, 1927

By Harry H. Nowlan

A heavy development campaign progressed during the year 1936 in South Texas1, following up important discoveries made in 1935. Oil and gas wells completed during the year were 1473 against 704 in 1935. The drilling program reached its peak of operations in June in consequence of offset requirements made necessary principally in Duval County in the Seven Sisters, Loma Novio, Lopez and Cole fields. There were six new fields discovered during 1936 as follows: Rhode in McMullen County; Peters, El Mesquite and North Kohler in Duval County; Wood in Starr County and Colorado in Jim Hogg County. No discovery of unusual consequence was made during the year. The pools mentioned above are simply in the primary stages of development. The most intensive exploratory work during the year was in Duval, Webb and Zapata Counties. Considerable activity also prevailed in Starr and Brooks Counties. Much significance is attached to the California Company's discovery in the Alta Mesa field in Brooks County, which is considered to be a deep-seated salt dome. The Comitas field, in Zapata County, developed some surprisingly good production in a shallow sand at 900 ft. and is being followed by a heavy wildcat campaign throughout that area in search of like production. In Starr County an active wildcat campaign is in progress in a continued effort to find new fields northwest of the Sam Fordyce field, in Hidalgo County. This play continues in a northerly direction through Starr and Jim Hogg Counties. New Fields Rhode.—The Rhode field, in southeastern McMullen County, was opened in May by the Magnolia Petroleum Co. with a gas well in the Whitsett (Upper Jackson) sand at a depth of 1810 to 1822 ft., this test is located in the southeast corner of sec. 86 on the Rhode ranch. Four gas wells have been completed, proving up a gas area of 1000 acres, more or less. Development will be slow because of lack of market for the gas.

Jan 1, 1937

By R. W. Raymond

The death of Mr. Stetefeldt, which occurred at Oakland, Cal., March 17, 1896, was a surprise, as well as a sorrow, to many of his friends and professional colleagues. In the Engineering and Mining Journal of March 28th, I published an obituary article, the substance of which, modified and enlarged by later information, forms the basis of the present biographical notice. I am indebted to Mr. Albert Arents, Alameda, Cal., and Mr. 0. H. Hahn, Monterey, Mex., life-long friends, and to Miss Pauline Anacker, of Gotha, Germany, a cousin of the deceased, for details which I could not have obtained elsewhere. Carl August Stetefeldt was born September 28, 1838, in the village of Holzhausen, in the duchy of Gotha, Germany, where his father was a Lutheran pastor. He was an only son, and (after the early death of a sister) an only child. In his boyhood he is reported to have been physically delicate, but mentally precocious. In 1847 his father was transferred to Hörselgau, near Waltershausen, where, besides discharging his pastoral duties, he kept a select private boarding-school, in which a few pupils received a training preliminary to the " gymnasial" course. Among these pupils (one of whom was the now famous Dr. Knorr, the discoverer of antipyrine) he included his own son, who, thus carefully prepared, entered in 1852, at the age of fourteen, the gymnasium at Gotha. The records of the gymnasium bear witness that his conduct in and out of school was " blameless," and his attention to study good." But his career as a "gymnasiast" was marked by an act of rebellion probably more startling then than it would be now. Being much more strongly attracted by the natural sciences than by the dead languages, he conceived a special aversion to Hebrew, and engaged in a conflict with the professor in that department, out of which he seems to have come victorious. At all events, he was not obliged to pursue further

Jan 1, 1897

(Under this heading will be published notes sent to the Secretary of the Institute by members or other persons introduced by members.) Experienced mining. engineer, Columbia School of Mines graduate, practical experience in drifting, shaft sinking and development work, also in mining, operating and equipping iron, copper, and zinc properties. Married, age 32, available at once. Open for position as superintendent or assistant. No. 462. Member, age 33, married, desires position as mining engineer or engineering executive.- Twelve years experience as mining engineer, geologist, and chief engineer of iron and copper properties. Experience in United States, Mexico and South America. Fluent Spanish. Technical graduate. Minimum salary $3000. No. 466. Member, technical, general superintendent and mill superintendent: Well experienced in latest methods of ore reduction, especially on copper and complex ores. Draft exempt. Not less than $250 per month considered. No. 469. Consulting mining geologist, member of Geological Society of America and A. I. M. E., Professor of Geology and Mineralogy, Lawrence College, desires temporary position during summer in mine surveying, mining methods, expert mine valuation or any exploration work or mine development. Applicant has had nearly three years' experience in gold mining in Mexico and many years professional mine examination work in all regions of Western U. S. Terms reasonable. No. 470. Member, mining engineer, age 46, desires engagement as manager of mining properties, coal or metal mines. Education and 25 years experience in all branches of mining. Have been successful with labor in the management of large properties. No. 471.

Jan 8, 1918

ROBERT VAN ARSDALE NORRIS, who died at his home at Wilkes-Barre, Pa., on April 20, 1928, was born at Newark, N. J., on May 2, 1864, of parents who were direct descendants of such sterling New Eng-landers as Governor William Bradford, John Alden and Timothy Dwight. He went to the Collegiate School in New York and then to the Colum-bia School of Mines where he graduated with the class of 1885, having among class-mates A. S. Dwight, E. N. En-gelhardt, H. L. Hollis, G. B. Lee, Richard Moldenke, Wil-bur Sanders, Joseph Struth-ers, E. A. Wiltsee, and I. H. Woolson. His marked ability even among so many men of unusual ability caused him to be chosen as assistant to Pro- fessor Munroe in the summer school of mining and survey-ing immediately after gradua-tion, and he shortly after was also inspector of dredging operations on the Maurice River improvement work, Millville, N. J. The follow- ing year he worked in the chemical laboratory of Herman Behr in Brooklyn, and toward the end of 1886 he joined the staff of the Pennsylvania R. R. Coal Co. and the Susquehanna Coal Co. as assistant engineer. Six years later he was made principal assistant en- gineer and in 1900 he was made chief engineer of these companies. In 1904, he withdrew from them and estab- lished an office as a consulting engineer at Wilkes- Barre, later taking his son, Robert V., Jr., into partner- ship with him. They acted as consulting engineers for the coal department of the Delaware, Lackawanna & Western R. R. Co., the Lehigh Valley Coal Co., Coke Bros. & Go., Inc., the coal department of the Pennsyl- vania R. R. Co., the Wilkes-Barre & Hazelton R. R. Co., the Sterling Salt Co., and others, specializing in ex- amination and appraisal of coal properties, and also matters of Federal taxation.

Jan 5, 1928

On Dec. 8, 1916, at a meeting held at the Massachusetts Institute of Technology, the John Fritz Medal was presented to Professor Elihu, Thomson, "for his achievements in electrical invention, in electrical engineering, in industrial development and,in scientific research." Professor Albert Sauveur presided. John J. Carty, chairman of the Presentation Committee of the Board of Award, made a short address-on the history and significance of the medal. He was followed by E. W. Rice, Jr., president of the General Electric Co., who spoke at length of the achievements of Dr. Thomson, whom he called "one of the world's most prolific and industrious inventors and scientists." Among other things, he said: "In the, field of electrical inventions alone, Professor Thomson has been awarded something over 550 United States patents, and in other fields; notably mechanical work, about 150 patent.,. he has made contributions to the world's scientific, and technical literature, in several hundred articles describing not only his own dis-coveries and inventions but making remarkably interesting contributions to scientific speculation and thought. "A skilled workman, he is always able himself to do the work which he asks others to perform. "His inventions are the result of such profound and accurate knowledge,. and developed with such skill, that they almost invariably work on the first, trial in accordance with expectation." Dr. Richard C. Maclaurin, President of the Massachusetts Institute of Technology, spoke of the personality of the man as well as of his accomplishments, as follows: "He has not only clone great things himself, but has shown ,in intense desire to help all who are struggling earnestly with scientific problems. He has proved an inspiration to an ever-widening circle of engineers and others who have entrusted him with their secrets and sought his help in overcoming their difficulties. They have done this knowing. that they had only to ask in order to get the full benefit of his

Jan 2, 1917

By Hans Strack

Electroluminescence of GaAs p-n junctions fabricated by simultaneous diffusion of sulfur and iron was investigated at 77°K. A narrow emission peak with a half width of about 4 kT in the energy range between 1.14 and 1.155 eu was attributed to iron. Other transition elements exhibited light emission in the vicinity of the iron peak, namely nickel between 1.15 and 1.16 ev and cobalt between 1.16 and 1.17 ev. The efficiency of the doping with iron depended on the amoz~nt of arsenic present. A weight ratio of arsenic to iron of 4:l was sufficient to observe the emission lines associated with transition elements. The presence of oxygen reduces the intensity of the light emission. In addition to the levels associated with transition elements, levels at 1.05 and 1.28 ev, probably due to lattice defects, are observed except in diodes fabricated in solution-grown GaAs. THE near band edge emission of GaAsp-n junctions has been studied extensively in the past.' GaAs devices utilizing spontaneous and stimulated near band edge emission are of considerable practical importance. Typical junctions are fabricated by diffusion of a heavily doped p region into degenerate n-type GaAs. Much less work has been done on investigating the radiative recombination via deep levels in lightly doped p-type material. This area is of interest in understanding the performance of GaAs n-p-n transistors. GaAs transistors show remarkable improvement in high-frequency performance and current-gain stability at high temperatures, when iron is added to sulfur during the emitter diffusion process. The present work was initiated to investigate deep-level electroluminescence of iron-doped GaAs p-n junctions fabricated on vapor-phase epitaxial GaAs and on solution-grown GaAs. For comparison several diodes doped with cobalt and nickel were studied. Iron, cobalt, and nickel have an electron configuration of the type

Jan 1, 1968

By Charles H. Moore

When lime and magnesia are used as fluxes in the smelting of titaniferous ores fluid, digestible slags low in iron oxide and high in titanium dioxide are produced. The mineral phases present in such slags are (Fe,Mg)O.2TiO2, CaTiO3, and minor amounts of silicate glass (or its devitrification products). The flux additions are added to the ore in relative amounts to crystallize a ratio of (Fe,Mg)O.2TiO2 to CaTiO2, of near the eutectic proportions of 60 pct (Fe,Mg)0.2TiO2 and 40 pct CaTiO3. FeO-Ti02 (ilmenite) remains present in the slag until the FeO content is reduced to approximately 8 pct. Op- timum slag composition is obtained by reducing the FeO content to between 2 and 6 pct. Continued reduction shifts he (Fe,Mg) 0.2Ti02 to oxygen deficient structures classified as MgTi30e and MgTi204. Further reduction yields titanium oxycarbides and freezes the melts.

Jan 1, 1949

By George H. K. Schenck, Peter G. Donald

There is an accelerating acceptance of change by management of cement companies. Diversity of response is noticeable in efforts across the country to reverse the downward trend in profits that brought margins in 1966 to the lowest point in 20 years. New concepts are emerging among managers as they seek to increase the efficiency in use of the basic corporate resources of men, capital and technology. The shift towards computerized control of cement manufacturing is making new gains as is diversification of cement companies into allied fields such as production and sale of natural and light- weight aggregates, crushed stone and concrete products. Increased interest in special products such as white cement and further moves overseas are also significant. Perhaps the most dramatic event of recent years occurred in Washington at hearings before the Federal Trade Commission where cement producers split on whether there should be FTC guidelines that would prevent ownership of ready-mixed concrete producers by cement companies.

Jan 4, 1967

By Arthur Wade

During the year 1938, there was some drilling in Queensland, New South Wales and Victoria, as follows: Queens1and.—At Hutton Creek, lat. (approx.) 25° 45' S.; long (approx.) 149°, drilling was done by Drillers limited (subsidiary Oil Search) to a depth of 4688 ft., to the Lower Permian(?). There were small gas showings. The hole mas abandoned. At Mt. Bassett, lat (approx.) 26" 20' S.; long. (approx.) 149", Roma Blocks Oil Co. No Liability drilled to a depth of 4033 ft. The hole bottomed in granite. There were small showings of' oil and gas above bedrock in what may be Permian but is not yet determined. The company intends to run a formation tester. New South Wales.—At Kulnura, lat. (approx.) 33" S., long (approx.) 151°, the Kamilaroi Oil Company Ltd. (subsidiary of Oil Search Ltd.) drilled to a depth of 6293 ft. The Permian, probably Upper Marine Series, was reached. Drilling is to continue. Victoria.—At Romawi, lat. (approx) 37" 50' S., long. (approx.) 147" 45', a dry hole 3246 ft. deep bottomed in the Jurassic and was abandoned. It was drilled by the Governments of the Commonwealth and the State of Victoria. At Lakes Entrance, 1st. (approx.) 37" 50' S.; long. (approx) 748", a small showing of' oil (a few pints a day) was obtained from a well drilled 1275 It., to the Upper Oligocene-Glaucnnitc series, by the Austral Oil Drilling Syndicate, No Liability. Future Drilling Preparations is are being made by companies fur further test drilling in 1939, and the Governments of the Common wealth and the State of Victoria are continuing test holes for information only in the Gippsland district of Victoria. In Papua and New Guinea, no test drilling was done in 1938, but several companies are carrying on geological investigation and it is expected that, some test holes will be drilled during 1939.

Jan 1, 1939

By Arthur Wade

During the year 1938, there was some drilling in Queensland, New South Wales and Victoria, as follows: Queens1and.—At Hutton Creek, lat. (approx.) 25° 45' S.; long (approx.) 149°, drilling was done by Drillers limited (subsidiary Oil Search) to a depth of 4688 ft., to the Lower Permian(?). There were small gas showings. The hole mas abandoned. At Mt. Bassett, lat (approx.) 26" 20' S.; long. (approx.) 149", Roma Blocks Oil Co. No Liability drilled to a depth of 4033 ft. The hole bottomed in granite. There were small showings of' oil and gas above bedrock in what may be Permian but is not yet determined. The company intends to run a formation tester. New South Wales.—At Kulnura, lat. (approx.) 33" S., long (approx.) 151°, the Kamilaroi Oil Company Ltd. (subsidiary of Oil Search Ltd.) drilled to a depth of 6293 ft. The Permian, probably Upper Marine Series, was reached. Drilling is to continue. Victoria.—At Romawi, lat. (approx) 37" 50' S., long. (approx.) 147" 45', a dry hole 3246 ft. deep bottomed in the Jurassic and was abandoned. It was drilled by the Governments of the Commonwealth and the State of Victoria. At Lakes Entrance, 1st. (approx.) 37" 50' S.; long. (approx) 748", a small showing of' oil (a few pints a day) was obtained from a well drilled 1275 It., to the Upper Oligocene-Glaucnnitc series, by the Austral Oil Drilling Syndicate, No Liability. Future Drilling Preparations is are being made by companies fur further test drilling in 1939, and the Governments of the Common wealth and the State of Victoria are continuing test holes for information only in the Gippsland district of Victoria. In Papua and New Guinea, no test drilling was done in 1938, but several companies are carrying on geological investigation and it is expected that, some test holes will be drilled during 1939.

Jan 1, 1939

I would like to congratulate the authors on an interesting paper and, in particular, on their justification of the use of superposition in treating gas wells. They state, however, that no theory has previously been developed lor treating the variable rate drawdown case. In a paper published a few years ago by my colleagues and myself, a method is described which allows a constant rate drawdown curve to be derived for any well. regardless of real rate variations. This method has the great advantage that it is not necessary to make any assumptions regarding the form or uniformity of the reservoir, and the derivation suggested by the present authors is simply an idealized case of our more general treatment. In the light of several years' experience in the derivation of constant rate drawdown curves: I would like to point out that the method proposed by Odeh and Jones may lead to confusing answers, particularly if applied over an appreciable time interval. The reason is that, if pressures are measured when a well is flowing, non-linearities in plots like Figs. 1 and 2 can arise due to either (1) changes in the skin factor with time and/or flow rate, or (2) an inhomogeneous reservoir. Separation of these two effects is only possible if some of the pressures used in the analysis are measured when the well flow rate is 0 or, in other words. during brief shut-in periods. REFERENCES 1. Arthur, K. B.. Metunomski, Z. G. and Ruche, Ms "Intetet ct methode d'utilisa tion des mesures de pression [)our Petude des gisemonts" Revue de T'I.F.P. (Nov., 1962) XVII, 1299. 2. Thomere, R. and Arthur, K. R.: "Analysis of the Pressure Bet~avior of a Production Well Subject to Interterence and Its Application to Reservoir Models", Paper SPE 1189 presented at SPE :Amund Fall Mecting Ireld in Denwer, Colo. (Oct. 3-6, 1965).

Jan 1, 1966

By John Stewart

The market at present supplied by shipments from the phosphate districts of Quebec, Ontario, and New York State requires high-grade ore, carrying from 75 per cent. to 90 per cent. of phosphate of lime. In sorting out such material by hand, much valuable phosphate is necessarily left in the "culls" or refuse, besides which, much phosphate-rock of low-grade is not now mined at all, because it cannot be made available by the crude method of cobbing and hand-sorting. The utilization of such material, which would, of course, greatly benefit this industry, requires either a mechanical separation or a chemical process which would concentrate the phosphate in a form suitable for agriculture. Considering the rich phosphate now shipped as the first class, we may arrange the lower grades in three classes, as follows: Second Class.—Cull-ore from the first class, and the mass of deposits having, as gangue, pyroxene or hornblende. The following table gives the hardness and specific gravity of the minerals concerned: Hardness Spec. gravity. Apatite,....... . 5 3.1 to 3.25 Crystalline limestone (pink calcite),. 3 to 4 2.5 to 2.9 Pyroxene,..5 to 6 3.23 to 3.5 Hornblende,.5 to 6 2.9 to 3.4 Feldspar (orthoclase),. .. . 6 to 6.5 2.5 to 2.6 It is evident that when pyroxene and hornblende are present in large proportions, this ore cannot be successfully concentrated by crushing and jigging. It may be reduced to fine powder by successive treatment in a rock-breaker and a Sturtevant or Frisbee-Lucop mill, or other suitable apparatus, and in this condition it could be largely used by applying it freely upon exhausted clay soils, such as occur in Quebec and Ontario. The occupants of these once fertile river-lands are, however, hard to move in the direction of such improvements. When water-power is at hand, the cost of crushing

Jan 1, 1893