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By A. A. Steel

DUring the summer of 1905 I was employed by the U. S. Geological Survey to investigate the geology, mining, and preparation of barite in most of the fields of the United States. The Eastern districts have been more or less completely described; the Virginia field in detail by Thomas L. Watson, in his paper, Geology of the Virginia Barite-Deposits,' and other fields in abstract, including statistics of production and references to current literature, by various authors.2 There have also been published a few details of the occurrence of barite in the lead-mines of Washington county, Mo.³ The other accounts of this district are erroneous and meager, and since this field is the most important one in the United States at the present time, a detailed description of the local geology seems doubly desirable. Barite-deposits are scattered over nearly the whole of Washington and adjoining counties, but the product is all mined from the areas indicated upon the sketch-map, Fig. 1, and is shipped from the stations of the St. Louis, Iron Mountain & Southern railway, between Blackwell and Potosi, from 45 to 60 miles SW. of St. Louis. The topography is for the most part gently rolling, with slightly graded streams, usually less than 200 ft. below the higher hill-tops. Along Mineral fork and Indian creek are some steep bluffs and cliffs, affording good exposures of the

Jan 1, 1910

Jan 1, 1900

Jan 1, 1909

Jan 4, 1976

Jan 5, 1976

Jan 1, 1936

By Joel Watkins

THE terms kaolin, china clay, ball clay, and paper clay are more or less loosely and interchangeably applied to a large class of white-burning clays. These clays are made up chiefly of hydrous amorphous (colloidal) aluminum silicates with variable amounts of free silica and other impurities in small quantities. Occasionally also the term kaolinite is wrongly applied to a white-burning clay, for kaolinite, is a mineral of definite chemical composition and definite crystalline form which occurs but sparingly in nature. It is not the purpose of this paper, however, to define or classify clays, or to enter into a discussion of the chemistry of clays. It is rather a general description of the occurrence and methods of mining of a kindred group of clays, and a discussion of their future economic aspect. In the Southern Appalachian States, the mining of white-burning clays has in recent years become an important industry. Although these clays are of several distinct types, which occur in as many localities under different geologic conditions, they are for the most part. primarily of the same origin. They are essentially the same in elementary constituents, and are largely consumed in the same industrial arts. From the standpoint of a mining engineer, therefore, and for convenience in comparison and correlation, it should be interesting to discuss them under one heading.

Jan 2, 1915

Jan 1, 1902

Jan 1, 1970

NORTH AMERICA. CANADA Canadian Army Overseas. Ball, H. D. Bridges. C. Butterill, H. J. If. Ladner, F. E. Lane, H. C. Alillar, W. A. ALBERTA Calgary.-Chonette, W. C. Clark, L. At. Corbett, C. S. de Hart, J. B. Dingman, C. W. Fath. A. E. Fulton. J. If. Cray, J. G. Johnson. R. V. McCutchin, J. A. *Slipper, S. E. Vin Buckirk H. A.

Jan 1, 1944

Jan 1, 1969

THE exhibits of mining equipment at the AMC Metal Mining Convention and Exposition will be the largest and most diversified ever shown to the metal and nonmetallic mining industry. Over 795 leading manufacturers have been assigned a total of 36,130 net sq ft of exhibit space - 49 pct more than the last such exposition. Following is a partial listing of exhibitors, the products they will show, and their representatives.

Jan 8, 1950

By A. S. Odeh

This paper analyzes the effect of limited entry to flow at the wellbore on the steady-state productivity of a well. Wells that have been opened to flow along a fraction of their productive interval are termed wells with limited entry. Previous work treated the cases of a partially penetrating well, a well producing from the central portion of the productive interval and a well in which several intervals equally spaced were open to flow. In this paper the open interval can be located anywhere within the productive interval. Thus, in a sense, it generalizes previous work. The finite cosine transform was used to arrive at a solution for steady-state flow of a slightly compressible fluid. The solution was programmed for a CDC 1604 computer. Numerical vaIues for rd = 660 ft, r, = 1/4 ft, and range of sand thickness of 20 to 200 ft are presented in graphical form. The effect of rd and r, values on the result is shown in a table. The correct calculation of skin and damage ratio in the presence of limited entry to flow is explained and illustrated by examples. Moreover, the paper shows how to calculate the net decrease in productivity due to the combined effect of limited entry and perforations. INTRODUCTION In some wells only a fraction of the productive interval is open to flow. Location of this fraction is usually dictated by formation characteristics and reservoir behavior. For instance, if a gas cap exists, the open interval is located away from the gas-oil contact to prevent any possible gas coning. Wells that intentionally have been opened to flow along a fraction of their productive formation are tened wells with limited entry. Obviously, unintentional completions of this type also exist. Limited entry to flow decreases well productivity. Magnitude of the loss depends on the fraction of the formation open to flow, on the thickness of the sand, on the location of the open interval and on the ratio of rd /r, where r , is well radius and rd is the drainage radius of the well. The use of pressure buildup data on producing wells to calculate the condition of the formation around the wellbore is an accepted practice. van Everdingenl and Hurst2 introduced the concept of she skin factor s considered to be due to a thin layer of different permeability immediately around the wellbore. These authors dealt with the case of a well of complete radial geometry, i.e., a well with open-hole completion that completely penetrates the formation. The presence of a low-permeability skin results in a loss of productivity, as does limited entry. Therefore, if pressure buildup data obtained on a well with limited entry are used to establish the presence or absence of skin (i.e., formation damage), and a correction is not made for this loss of productivity, the calculations would result in an erroneous skin value. They might indicate the presence of formation damage when in reality there is none, or they might indicate a value larger than the true value. This could lead to an incorrect basis for planning remedial measures. Muskat3 studied the problem of partially penetrating wells for the case of incompressible flow. He presented equations and figures which allow estimation of loss in productivity. Brons and Marting,4 using equations based on Nisle's work,5 studied the loss of productivity for three cases. The first was for a partially penetrating well; the second was for a well producing from only the central portion of a productive interval; and the third was for a well in which several intervals equally spaced were open to flow. Their work was for steady-state depletion-type reservoirs wherein the well radius of drainage is established and the fluid is considered to be slightly compressible. Considered in this paper is the problem of wells with limited entry in which the open intervals are located anywhere within the productive sand. The finite cosine transform is used to arrive at a

Jan 1, 1969

By H. H. Podgurski, Hsun Hu

Large cryslals of high-purily iron (99.996+ pcl) cannot be obtained by the usual strain-ameal technique. Repealed phase transformation by thermal cycling prior to crilical deformation improves the capabilily of cryslal growith but fails to yield satisfactory crystals. Imperfect columnar crystals can be produced by the phase-transition method. The addition of a small amounl (0.005 wl pet) of nilrogen IT was reported'-4 that for metals of very high purity the usual procedures of the strain-anneal technique fail to produce large crystals. This was eliminates practically all the difficulties in crystal growth by the normal strain-anneal procedures. An actual example is presented, showing that most parts of a strip have been converted into a large crystal by this method. The addition of nitrogen, which can be removed from iron with less difficulty, is believed to be more desirable than carbon additions for the same purpose. thought to be due to the strong tendency for recovery in the high-purity metals: hence the critically strained matrix undergoes polygonization instead of recrystallization upon annealing for crystal growth. Talbot1,2 succeeded in overcoming this difficulty by adding 0.03 to 0.04 pct C to high-purity iron before critical deformation. followed by annealing in hydro-

Jan 1, 1965

Jan 1, 1969

Jan 1, 1933

New Products Equipment

Jan 11, 1950

By R. F. Mehl

Jan 1, 1936

Jan 1, 1931

By E. C. Pechin

AT the suggestion of some members of the Institute, attention is called to the record of the working of Dunbar Furnace during the twelve months ending in January, 1874. During this period, with a product of over eleven thousand gross tons, not a single ton of

Jan 1, 1874