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By Max Stern

ROOM and pillar coal mining methods employed in the United States keep the roof at original height by leaving untouched pillars of coal in the face area. But, German coal mines of the Ruhr district are exclusively operated on the longwall system. With this method the whole length of the coal face advances and the roof in the face area sinks 10 to 15 pct of seam thickness. Behind the face the roof may drop 50 to 80 pct of seam thickness due to the high rock pressures encountered at average mining depth of 2250 ft. Mining depth is increasing 20 to 30 ft per year.

Jan 5, 1953

By Eugene S. Perry

The most notable development in oil and gas operations in Montana during 1938 were extensions to the Kevin-Sunburst and Cut Bank fields. No new fields were discovered, although about 20 widely scattered wildcat wells were operated. Within or adjacent to proved fields about 100 wells were drilled, resulting in 81 oil wells and 14 gas wells. In general, production activities were below those of 1937, largely because of market conditions. Markets for crude were improved late in the year by construction of refinerirs at Pocatello, Idaho, Spokane, Washington and Cut Bank; and also by price concessions. However, demand was much

Jan 1, 1939

By Eugene S. Perry

The most notable development in oil and gas operations in Montana during 1938 were extensions to the Kevin-Sunburst and Cut Bank fields. No new fields were discovered, although about 20 widely scattered wildcat wells were operated. Within or adjacent to proved fields about 100 wells were drilled, resulting in 81 oil wells and 14 gas wells. In general, production activities were below those of 1937, largely because of market conditions. Markets for crude were improved late in the year by construction of refinerirs at Pocatello, Idaho, Spokane, Washington and Cut Bank; and also by price concessions. However, demand was much

Jan 1, 1939

By M. M. Singh

Coal mine operators are obligated to mitigate or plan for subsidence under the new regulations. This paper presents the types of subsidence control measures that may be employed to meet these requirements, which include: changes in mining methods, strata stabilization after coal extraction, construction of specially designed surface structures and foundations to accommodate ground movements, and comprehensive planning and coordination of surface land use with underground mining. The basic principles of these techniques, along with specific procedures that may be followed to implement them, are briefly discussed. Subsidence control methods that are currently being investigated are mentioned.

Jan 1, 1985

(Members are urged to send in for this column any notes of interest concerning themselves or their fellow-members.) The following members registered at Institute headquarters during the month of April: J. C. Ralston, Spokane, Wash. E. P. Ross, Johnson City, Tenn. C. H. James, London, Eng. F. L. Garrison, Philadelphia, Pa. E. H. Benjamin, Oakland, Cal. A. Radcliffe, Copiapo, Chile. W. H. Shockley, Palo Alto, Cal. S. S. Wyer, Columbus, Ohio. A. C. Mauney, Salisbury, N. C. W. B. Kunhardt, Reading, Pa. A. W. Newberry, Los Angeles, Cal. W. E. Saunders, Philadelphia, Pa.

Jan 5, 1913

SECTION I PAGE PAGE Bulletin Wanted v Northwest Mining Convention St. Louis Meeting v (Columbia Section) xvi Proceedings of the Meeting of Affiliated Student Societies... xvii the Board of Directors vii Harrison W. Craver, New Li-¬ John Fritz Medal viii brary Director xviii Herbert C. Hoover, Food. Con Library xx troller viii Pamphlets for Sale xxii President's Prize ix Membership xxxvi Emmons Memorial Fellowship. x Biographical Notice of Her¬ Meetings of Various Societies. x Mann A: Keller : lviii Personal xi Institute Committees lix Employment xii Officers and Directors lxvi Local Section News xiii

Jan 5, 1917

By N. O. Johnson, R. A. Westin

Polychlorinated biphenyls were the basis of non-flammable askarel dielectric liquids wed in electrical equipment made between 1929 and 1978. Although PCBs were widely used in mine electrical equipment, the toxicity and environmental persistence of this chemical led Congress to ban its manufacture and use. Bureau of Mines Information Circular 8838 summarizes the regulations imposed by the EPA on the use and disposal of PCBs, and describes the limitations of available substitutes. Recent changes in the regulations will impose additional requirements on the use of PCBs by the mining industry. This paper is an update of the material presented in the Bureau of Mines information circular.

Jan 1, 1983

By Frank C. Greene

Drilling in Missouri in 1944 was nearly treble the rate of 1943 because of continued development of the Tarkio pool in Atchison County and the preparation of a pool in Jackson County for a water-injection project. The pipe line from the Prairie Point gas pool in Platte County was in operation throughout the year of 1944, but several of the shallow oil pools in Cass and Jackson Counties were off production during much of 1944 because of a shortage of help. Table I gives a summary of activities by counties. The total footage drilled was 41,475 .ft., of which 21,187 ft. was by rotary tools and 20,268 ft. by cable tools.

Jan 1, 1945

By George Straghan, Ralph Thomas

OIL production in Kentucky in 1941 was 5,191,024 bbl., one barrel less than in the preceding year. The total completions for the state numbered 714, of which 256 were gas Manuscript received at the office of the Institute Feb. 26. 1942. * Geologist, .Kentucky Weal Virginia Gas Co., Ashland, Ky. † Geoloneist. Inland Gas Co.. Ashland. Kv. producers, 220 oil wells, and 227 dry holes. The total number was 95 more than in 1940. No new important oil or gas pools were discovered. The number of dry tests was large, although many of the dry holes could be considered wildcat tests. In western Kentucky, 365 wells were drilled, of which 145 were oil producers,

Jan 1, 1942

By Ralph Thomas, George Straghan

OIL production in Kentucky in 1941 was 5,191,024 bbl., one barrel less than in the preceding year. The total completions for the state numbered 714, of which 256 were gas Manuscript received at the office of the Institute Feb. 26. 1942. * Geologist, .Kentucky Weal Virginia Gas Co., Ashland, Ky. † Geoloneist. Inland Gas Co.. Ashland. Kv. producers, 220 oil wells, and 227 dry holes. The total number was 95 more than in 1940. No new important oil or gas pools were discovered. The number of dry tests was large, although many of the dry holes could be considered wildcat tests. In western Kentucky, 365 wells were drilled, of which 145 were oil producers,

Jan 1, 1942

By P. Sen

Frequently during the processing of minerals very fine particles are generated which are difficult to recover by conventional separation techniques and are rejected with waste water from mills. A method has been evolved for the continuous recovery of such fines by allowing the suspensions to flow through a rotating cylinder. Theoretical analysis of the trajectory of particles have shown that the efficiency of separation increases with R.P.M., tube diameter, particle diameter and density. Experiments carried out with the overflow from a hydrocyclone containing particles in the size range of 2-10 microns gave a separation efficiency of 60-70% with an R.P.M. of 3500 of the rotating tube.

Jan 1, 1980

By R. L. Wiegel

The National Science Foundation, Erie Mining Co., and University of Minnesota Mineral Resources Research Center jointly sponsored a project to demonstrate the use of a small computer in the control of cyclone overflow size on one line in the Erie Mining Co. concentrator. The Erie circuit, similar to most taconite circuits, uses magnetic separators to reject tailings following each stage of grinding, resulting in additional variations in the demands made on the grinding circuit because of weight rejection fluctuation. Mathematical models were developed for rod milling, ball milling, hydrocycloning, fine screening, and five stages of magnetic separation. These models were used in concert to simulate the operation of Erie's circuit from rod milling through finisher magnetic separation.

Jan 1, 1980

By Harold W. Aldrich, Frederick Laist

After a series of experiments covering a period of about three years, extending from the spring of 1912 to the spring of 1915, a 2,000-ton leaching plant for the treatment of the accumulated copper concentrator tailing was built and put into operation. During the experimental period, the first step was that of laboratory experiments or beaker leaches. The results on this small scale were so satisfactory that a small operating plant, capable of handling 5 tons of roasted tailing per day, was installed. Again, the results proved satisfactory and an 80-ton plant was built and operated continuously from August until February, 1913. In this plant, full-sized roasting and leaching units were

Jan 1, 1917

By Robert S. Schecter, Paul M. Bommer

This paper presents the development of and results from a computer model of in situ uranium leaching. This model uses a streamline-concentration balance approach and is useful with a wide range of reservoirs. It can be used with any type of well system, in a reservoir with or without boundaries, and with any form of descriptive kinetics. The model also includes the effects of dispersion and consumption of oxidant by minerals other than uranium. The effects of areal sweep, variable uranium concentrations, variable permeability, and the presence of oxidant consumers on uranium production are shown and discussed.

Jan 1, 1979

By Thomas F. Evans

This study shows that statistics on the rate of coal dumping can measure the effectiveness of freeze conditioning agents. The use of appropriately indexed dumping intervals or interval logrithms provides a more sensitive indication of unloading problems than does a simple calculation of average loading time because of the abnormal form of the distribution of dumping intervals. The paper presents information that indicates suitably applied coal freeze conditioning agents are effective in reducing coal handling problems attributable to frozen coal. Graphs and figures show that the severity of coal freezing potential due to subfreezing temperatures is proportional to the exposure time and average departure of the temperature from the freezing point.

Jan 1, 1982

By L. F. Mashburn, T. J. Ferree

A Reichert cone concentrator was installed in an aggregate plant circuit to recover the extremely fine "flour gold" known to exist in the deposit. The gold content of the bank- run gravels averages about 0.1 g/t-about $1.29/t, based upon $12.86/g ($400 per oz) gold. The fineness of the gold averages between 950 and 960. The Reichert cone, in conjunction with a conventional shaking table, recovers in excess of 85% of the gold. A screen analysis of the gold particles shows 44.1 % is - 74pm (-200 mesh) in size. The plant operates with a two-man crew.

Jan 1, 1983

By James Park

The principal gold-bearing formation is of volcanic origin, consisting of a great accumulation of andesitic lavas, tuffs, breccias and agglomerates of lower Tertiary age. These rocks everywhere bear evidence of having been subjected to the prolonged leaching-action of thermal waters, doubtless accompanied by steam and acid vapors. They are found in all stages of decomposition or alteration; and in many mines the hard blue andesite can be seen to pass by a series of almost insensible gradations into a soft, or fairly hard, greyish yellow or blue

Jan 1, 1900

By R. V. Ramani, T. S. Kovach

In many instances, the actual production from a longwall face does not equal the planned capacity. General problem areas that have been identified include face length and panel depth, face area and gate entry roof support, face conveyor and shearer wear, outby haulage system failures, number of entries in longwall gate development, and longwall move time. The performance of a longwall face is totally dependent on the interaction of these and other factors. To explore fully these interactions, a systems analysis of longwalls has been performed. In this paper, the systems approach, the factors considered in the analysis, and the results of the analysis are presented.

Jan 1, 1985

Meeting, Apr. 25, 1913.-President Rand recommended the appointment of the Nominating Committee (see p. i), and a Committee on the Use of Electricity in Mines (see p. xliv), which committees were duly approved and appointed. President Rand recommended the establishment of. a Committee on Mining Methods, and requested authority for the President to appoint the members of this Committee, both of which recommendations were approved. The name of the Committee on Economic Geology was, at its own request, changed to the Committee on Mining Geology. The request of the Iron and Steel Committee, that a meeting of the Institute, under the auspices of this Committee, be held in the latter part of October, the place of meeting to be decided later, was granted.

Jan 5, 1913

Meeting of Dec. 18, 1914. Charles F. Rand, Karl Eilers, and William L. Saunders were appointed a Committee to audit the accounts of the Institute. The matter of the Committee to investigate the relative merits in metallurgical work of turbo-blowers and the reciprocating blowing engine was laid on the table. Benjamin B. Thayer was elected representative on the Board of Trustees of the United Engineering Society to succeed James F. Kemp. Upon the recommendation of the Committee on Membership, 32 Members, 8 Associates, 3 Juniors were elected, and the status of one Associate was changed to that of Member. Twenty-six members owing dues for from three to six years were dropped from the rolls in accordance with the provisions of the Constitution.

Jan 2, 1915