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By Richard C. Timberlake

The disposal of phosphatic clays has presented a problem to the phosphate industry since the mining of phosphate rock first began in Polk County. As the flotation process was introduced in the late 1920's the problem of clay disposal was increased significantly since clay is present in proportionally greater quantities in reserves yielding flotation concentrates. Because of their physical character and the tremendous surface area per unit volume, these clays have the characteristic of retaining large volumes of water as they are slurried during processing. The disposal of clay and the recovery of a portion of the water require settling areas with a capacity ranging up to 2 cu ft for each cubic foot of phosphate matrix mined. According to a recent study by the Bureau of Mines, the average cost for disposal of these wastes is 24.5[c] per ton of product. This is a major cost of phosphate rock production.

Jan 12, 1969

By Thomas M. Drown

THE method usually employed in accurate determinations of sulhur in pig-iron and steel is to treat a weighed sample of borings in a flask with muriatic acid, and to pass the gaseous products through an alkaline solution of lead or silver, which precipitates all the sulphur of the sulphuretted hydrogen in the form of sulphide of lead or silver. The sulphide thus formed is subsequently oxidized by aqua regia, bromine, or other oxidizing agent, and the sulphuric acid formed precipitated in the usual way by chloride of barium. I have substituted for the alkaline metallic solution, a solution of permanganate of potash in the strength of one gramme of permanganate to 200 cubic centimetres of water, and find that it gives results quite as accurate as those obtained by using an ammoniacal solution of silver. By the employment of the permanganate it will be readily seen that there is considerable saving of time and work. In order to test the accuracy of the method, six samples of pig-iron borings were weighed out (about six grammes each) and treated identically

Jan 1, 1874

W: 0. HOTCHKISS, Madison, Wis. (written discussion*).-Mr. George's paper on. "The Wisconsin Zinc District" is a very complete and clear description, which it is a pleasure to read. His discussion of the origin of the ores is the least satisfactory part, and Mr. George correctly states present knowledge when he begins his paragraph on a origin with the words "the general supposition is, etc." There is still much to be learned regarding the details of the processes by which the ores have reached their present situation. In this the Wisconsin district differs not at all from other mining districts. It is my hope that Mr. George and others, equally clear-thinking, who are in close touch with these operations will be able at an early date to give us more information on this subject.

Jan 3, 1918

By W. H. Nielson, L. S. Diaz

Several techniques are presented to adjust small errors inherent in data collected from material balance measurements on the flotation process. The basic technique used is a Lagrange multiplier adjustment of the filtered data taken from the equipment measurements. The raw data are adjusted such that material balances are closed. The adjustments to each data point is inversely proportional to the square of the standard error of measurement. Problem areas in equipment utilization are discussed. Typical results from on-line measurements are presented. This technique can be applied to either on-line process measurements or metallurgical test data.

Jan 1, 1973

By John H. Bassarear

By 1968, Cyprus Pima was milling 34.5 kt /d (38,000 tpd) of copper ore using a conventional flowsheet consisting of three stages of crushing, rod milk and ball, mills. A 13.6 kt /d (15,000 tpd) expansion was put onstream late in 1971 using primary crushing, semiautogenous milk, and ball mills. Identical ore is treated in both concentrators. This paper shows the weight and life of each liner for each crusher and each mill over a four year period from 1974-1977. Media consumption is shown for the same period and a comparison is made between the two reduction methods.

Jan 1, 1983

By N. A. Ziegler

A certain amount of interest has been indicated recently in the resistance to oxidation at high temperatures of iron-aluminum alloys (rich in iron). Hautmanl published a paper in which some interesting results are given. According to his paper, only alloys containing at least 8 per cent aluminum indicate a marked improvement in their resistance to oxidation. At about this aluminum content, however, alloys become brittle, which considerably reduces their commercial value. About two years ago the author performed a series of experiments, the results of which are presented here. A series of iron-aluminum-carbon alloys was prepared by melting electrolytic iron, aluminum and high-carbon iron alloy in an induction vacuum furnace.2 The list of these alloys is given in Table I. Each alloy was forged in the ordinary way to All carbon determinations were performed by " Yensen " method. [N. A. Ziegler: Recent Developments in Analysis of Carbon in Iron and Iron Alloys. Trans. Amer. Electrochem. Soc. (1929) 56, 231.1

Jan 1, 1932

By Frank M. Howell, Claude E. Schmidt

To counteract the spiralling costs of labor and materials against the fixed sale of its product, namely, gold at $35 per oz, Homestake Mining Co. has revised the milling flowsheet once and effected increases in the daily milling rate twice in the past 12 years. During this period the mining department has been able to hold production costs steady by increased productivity through technical improvements and utilization of the most modern mining by CLAUDE E. SCHMIDT and FRANK M. HOWELL, JR. 46-MINING ENGINEERING, APRIL 1963 equipment. The flowsheet alteration occurred during 1951-1953 when the two crushing plants at the shaft head frames were converted to a three-stage crushing system with the third stage closed circuited to produce a minus 5/8-in. product as rod mill feed.

Jan 4, 1963

By Ferdinand S. Ruttmann

The Tilly Foster iron-mine is situated in the southeastern part of Putnam County, New York, about fifty miles north of New York City, on the line of the New York City and Northern Railroad. There are a number of deposits of magnetite scattered throughout the county, the most important being those known as the Tilly Foster, the Mahopac, and the deposits of the Croton Magnetic Ore Company. (See the paper of Mr. Wendt, Transactions, xiii., 478.)

Jan 1, 1887

By George E. Beavers

It is well to understand at once that converter gas is always mixed with copper blast-furnace gas at Copperhill before entering the Glover tower, and, at times, roaster gas is also added along with the converter and blast-furnace gas. Fig. 1 is introduced to show the variations in the sulfur dioxide content of the gas and the ability of the acid-plant operator to control the variations, resulting in a very even grade at the Gay-Lussac tower entrance. The sulfur dioxide content of the gas entering the Gay-Lussac tower must be low and regular to assure low niter consumption. The blast-furnace gas alone is rather uniform as regards sulfur dioxide content and the variations, as shown in Fig. 1, are chiefly caused by converter changes—out for charging, slag pouring, copper pouring, and, of course, the "finish." The combined gas during the converter finish is, at times, almost free of oxygen and the sulfur dioxide content reaches 13.0 per cent. At such times air is added at the Glover tower.

Jan 1, 1934

By Immo H. Redeker

Abstract-North Carolina is the leading state in the US in lithium mineral production. Spodumene is mined in open Pits and concentrated by flotation by the two companies, Lithium Corp. of America and Foote Mineral Co. North Carolina State University has a mineral research laboratory in Asheville, N. C., with trained personnel, batch and pilot plant facilities to assist in the state's mineral development. The NCSU Minerals Research Laboratory assisted both lithium-producing companies with spodumene concentration problems and has lately worked closely with Lithium Corp. of America to develop the best flowsheet for spodumene and byproduct recovery. The concentration of North Carolina spodumene and byproducts from pegmatites is presented and illustrated with figures.

Jan 4, 1979

By Alan K. Burton

Having estimated fleet size and productivity, the next and final step in this analysis is to introduce cost. Total cost of the system is a combination of capital, operating, and any other external costs that may be incurred. The last item, external costs, can be particularly important when comparing one size or type of truck fleet with another. Once costs are calculated, it is possible to compare systems on a total cost, cost per hour, cost per ton, or any other basis that is required. Methods used vary from simple owning and operating costs to sophisticated discounted cash flow analyses involving optional fleet replacements over the project life.

Jan 1, 1976

By Clifton W. Livingston

So many factors influence blasting results that theories and rules are usually dismissed as impractical; the practice prevailing today is arrived at by cut and try. Usually the first step is to experiment with drillhole patterns and spacing until an arrangement is found that gives best results. The next step is to experiment with different types of explosives and sequences of blasting until the most satisfactory degree of fragmentation is achieved and until no further reduction in cost is immediately apparent. Improved fragmentation is generally attributed to the type of powder used, the sequence in which the holes are blasted, or the use of millisecond delays. Various types of drill rounds have been evolved in tunneling operations, underground development headings, and stoping, and various patterns of blasting in open pit mines and quarries. These practices usually are carried from mine to mine or from district to district, and great skill is exercised by those experienced in the art of blasting.

Jan 1, 1960

By A. L. Mular

Several capital cost estimation procedures are reviewed briefly, although the factored estimate method is discussed in preference. A table of cost versus equipment parameter data is provided, where the cost may be updated from the current value of the M&S cost index for mining and milling. Cost equations are useful to prepare computer programs which perform capital cost calculations. The use of the factored estimate method is illustrated.

Jan 1, 1978

By Thomas M. Drown

The following description of an attempt to separate bituminous coal from its slaty and mineral admixtures without the aid of jigging, was suggested by the successful use of dense solutions (such as the double iodide of mercury and potassium and cadmium borotungstate) in the separation of the mineral components of igneous rocks.* In the case of coal it is essential that we have a solution of a specific gravity greater than the coal, and less than the mineral or slate associated with it. Further, in order that such a solution should be practically admissible, it must be cheap and readily obtainable. Calcium chloride fulfils all these conditions, although it is not intended to be affirmed, in the absence of actual trial, that its use on a large scale would be economically successful. The records of experiments on several samples of bituminous coal

Jan 1, 1885

By L. G. Schulz

THE possibility of using reflected X-rays to produce images of crystals was explored by Barrettl who developed simple experimental procedures for X-ray microscopy and who showed by numerous examples the great range of information that could be made available. In his method characteris radiation is used to produce an image of a limited area of the sample on fine-grained film, this image subsequently being enlarged approximately X100. A somewhat different method will be described here;' white radiation from a fine-focus X-ray tube-"' is used to produce an image of a relatively large area of a single-crystal surface. part of the sample; therefore, white radiation is needed. The resolution in the image formed on the photographic film will depend on the size of the focal spot of the X-ray tube. If the sample is made

Jan 1, 1955

By L. W. Saperstein, W. B. Wells, L. B. Phelps

Several strip mine spoils are being examined to better understand their physical nature. The spoils were core drilled and each hole was logged using a nuclear geophysical tool to obtain bulk density data. Bulk density is an important property which provides insights into spoil porosity as well as other characteristics. The holes were drilled in spoils representing a variety of overburden removal methods, spoil ages, spoil depths, and area lithology. The relationship between bulk spoil density and mining method, spoil age, spoil depth, particle size, and lithotype is presented.

Jan 1, 1984

By G. T. Lineberry, L. Adler

Reduced clearance a one of the most important characteristics of encumbered space in underground coal mining. Another key variable is the maximum velocity at which a piece of mobile mining equipment can operate in this limited space. Typical velocity-clearance curves for different mine transportation systems are developed and characterized. Applications of the relationships are examined, emphasizing their significance in designing and controlling mine materials handling system.

Jan 1, 1985

By Walter Kauenhowen

The crude-oil production of Germany without Austria during 1938 amounted to 3,864,518 bbl., representing an increase of 21.7 per cent over the 3,173,373 bbl. produced in 1937. Adding the Austrian production, the crude-oil production of the new German Reich totaled 4,259,717 bbl. during 1938, representing an increase of 25.3 per cent compared with the respective figures of the previous year. According to published official data, and using a conversion factor of 1 metric ton equaling 7 bbl., the oil production of Germany in 1938 was as shown in Table 1. A semiofficial publication1 states that the program of the crude-oil industry for the second year (1938) of the four-year plan was successfully accomplished. According to the same source, new drilling developments at the following localities were promising: Reitbrook near Hamburg, Heide in Holstein, Eicklingen-Sandlingen near Celle, Steimbke near Nienburg, Worms in the Rhine Valley, Gifhorn near Braunschweig, Mölme near Oberg, and at other places. The drilling activity for oil is illustrated by the figures in Table 2.

Jan 1, 1939

By J. C. Jr. Vaughan

ALTHOUGH a considerable amount of practical importance attaches to systems involving gases and molten metals, little is known regarding the effects of alloy elements upon the solubility of gases in liquid iron. The solubilities of hydrogen1 and nitrogen2,3 in pure liquid iron are known and it has been shown that small amounts of silicon and aluminum3 exert only a small effect upon the solubility of nitrogen but greatly increase its rate of solution. This paper presents the results of a study of the Solubility Of nitrogen, at pressures approximately one atmosphere, in molten iron containing up to 1.5.5 per cent silicon.

Jan 1, 1939

By A. D. Bryant

APPROXIMATELY 2 1/2 million tons of silica sand and ground silica with a value of $7.25 million is produced annually from the Ottawa, Illinois, district. These silica products come from the well known St. Peter sandstone formation which covers part of the Mississippi Basin extending from St. Paul on the north to the central part of Arkansas on the south and from Muncie, Ind., on the east to Kansas City on the west. Practically the whole state of Illinois is underlain by this formation except where removed by erosion. Sand produced from the St. Peter sandstone in the Ottawa district is noted for its purity, uniformity, and quality. In addition to various screened grades for industry about 10 pct of the total production of the Ottawa district is ground into silica flour for use in glass, abrasives, enamel, porcelain, tile, for foundry and filter sand, and other uses.

Jan 3, 1953