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By David S. Cahn

Pilot-plant and laboratory tests were made on blends of steel plant flue dust and portland cement to determine whether the flue dust could be pelletized for use as a source of iron in dry process cement manufacture. Strength and setting time results showed that an acceptable agglomerate can be made with a Type II portland cement binder. Abrasion-resistant and well-sized pellets were made in a horizontal drum, using a simulated closed circuit, with a binder content of 7.5% and a moisture content below 15%. Pellet quality was found to be relatively insensitive to changes in binder concentration above 5%. Simulations of stockpiling and weathering indicate that little difficulty would be encountered with use of the flue dust pellets in cement plants.

Jan 1, 1972

By E. C. Harder

HERBERT K. SCOTT, London, England (communication to the Secretary*).-I am acquainted with the manganese-ore deposits of Russia, India and Brazil, and agree generally with the statements contained in the paper regarding those deposits. The information given by Mr. Harder regarding the Chilean deposits is very welcome. When examining the Caucasian deposits, I endeavored to determine the quantity of ore originally contained in the deposit, and by deduction, the amount remaining for extraction. These calculations were rendered possible by the great extent of the outcrop and the extensive work that had been carried on in the deposit. In making the first estimate, the quantity of manganese ore and associated sterile material in the bed was measured in a large number of

Jan 12, 1916

By Richard Maclin Stewart

A priest at Shenandoah, Pa., one day persuaded the president of the Philadelphia & Reading Coal & Iron Co. to slush breaker waste and culm into old mine workings in order to save his church from being destroyed by surface subsidence. The year was 1864, the project was successful, and history recorded the first use of hydraulic backfilling. Shortly afterward, the method was applied to several eastern coal mines for area fill to control subsidence. In 1884, hydraulic backfilling was used to control a mine fire in the Schuylkill region of Pennsylvania. The idea was taken to Europe by German engineers and developed successfully at the Myslovitz colliery in Upper Silesia in 1901. From there it was applied to several mines throughout Europe.

Jan 4, 1958

By B. Yarar

Samples of coal from an adit in the Fording River District of British Columbia showed hydrophilic properties between depths of 0-24.5 m (0-80 ft) and was naturally hydrophobic at greater depths. Laboratory experiments indicated that weathered samples (i.e., those mined at 0-24.5 m) could be upgraded by froth flotation at pH32 following slimes removal. The i.e.p. of samples varied regularly between pH = 1.6-4.1, the weathered fractions being at the lower end of the pH scale. These values followed a pattern comparable with the flotation behavior of samples. A patchwise structure for coal surfaces determining the resultant disjoining pressure which in turn determines flotation-non-flotation relationships is postulated.

Jan 1, 1983

By Douglas W. Fuerstenau, Kalanadh V. S. Sastry

Mathematical considerations of green ball growth in a balling device by the mechanisms of layering new feed onto seed or recycle pellets are presented. An experimental procedure was developed for investigating the agglomerate growth by layering in which the addition of feed to a batch of seed pellets was made cyclically. Using this procedure, the layering growth mode under partial feed consumption and no seed generation conditions was investigated experimentally in a laboratory balling drum as a function of such operating variables as moisture content of the material, feed rate, and the size distribution of the seed pellets. The experimental results were analyzed in the context of the model equations and the layering growth constant was estimated as a function of the operating variables.

Jan 1, 1978

By James E. McNulty

Coal reserve estimates are prepared using a simple equation: the product of area, bed thickness, density and recovery factors. Each of these elements involves a degree of risk based on certain assumptions. Reserve area, thickness and density rely on certain physical data whose accuracy, reliability and sufficiency may be problematical. Estimates of recovery factors for mining and coal preparation are often subjective. Most reserve estimates assume, sometimes incorrectly, that the subject reserves will be completely extracted. The principle that certain coal resources are reserves, if they can be considered economically recoverable at the time of determination, needs to be reexamined in the light of recent market cycles. Reserve estimating requires the exercise of judgments, the validity of which reflect the qualifications, experience and objectivity of the estimator.

Jan 1, 1985

By Lawrence F. Schubert

Instrumentation is not a stranger to the minerals processing industry. In fact, very few plants now exist that haven't to one extent or another adapted operations to instrumentation. But with the rapid growth of such controls has come the need for effective departments composed of men trained to maintain and repair the instruments; here is where many firms fall short. The importance of the role an instrument department should play is underscored by the omnipotent effects which instruments often exert over an operation. Reserve Mining Co. is an example: while instrumentation at this taconite plant represents approximately 2% of the process equipment cost, a breakdown of instruments may result in the ineffective use (or complete shut-down) of the other 98% of plant investment.

Jan 7, 1966

By R. A. Turpin

Bethlehem Steel's Research Department is developing a set of computer programs as mine-planning tools for Bethlehem's coal mines. Several of these computer programs have been completed and have been in routine use by Bethlehem Mines personnel since early 1975. The production scheduling and ventilation planning programs have been installed on an interactive time-sharing computer. The use of time sharing allows mines in remote locations to access these planning tools through standard phone lines and low-cost computer terminals. The capabilities of the interactive production scheduling and ventilation planning programs are briefly described. The advantages of implementing them using time sharing are discussed. A case study illustrates some of the benefits that planning based on the use of these programs has already provided.

Jan 1, 1977

By Henry N. McCarl, John J. Dran

In recent years, market rates of interest have risen well above their historical long-term average. Also during this period, the short-term variability of interest rates has been greater than in prior years. Interest rates have a significant effect on the operation of our economy. They influence the extractive industries in a number of ways. Their major long-range impact is on in- vestment decisions-specifically the valuation of mineral deposits. An understanding of the factors that influence interest rates is important to the engineer or businessman who makes the investment decisions for the mining company. The effect of changes in the market rate of interest on the value of mineral reserves is critical to the future financial success of the mining enterprise.

Jan 6, 1977

By William C. Peters

The experiences of exploration crews with mineral land acquisition could be graphed to show a correlation with the natural law that everything tends to become more so. A single step, such as that of taking a series of deep soil samples, is sometimes delayed until some sense can be made from floating unpatented claims which are obscure in orientation as well as position-placer claims, overlapping lode claims, location posts with empty Prince Albert cans and claims with no apparent assessment work for ten years. Add to this some patented claims without monuments, a state or federal withdrawal area which may or may not invalidate preexisting claims, a loosely defined tunnel site, and some ranchers who understandably resent the separation of surface rights from mineral rights.

Jan 1, 1970

By Alexandre Mussard

How do you make a mine out of 500 000 kg (1.1 million lb) of uranium oxide contained in a low-grade deposit with high clay content? Confronted with these limited reserves and mineralogical problems at France's St. Pierre du Cantal uranium deposit, engineers adopted a rather unusual mill process to keep capital costs to a minimum. Crushing and grinding were eliminated by using a high pressure monitor to slurry ore directly from stockpiles. After mechanical separation of the high-grade fines from low-grade sand, the sand fraction is washed of clay to increase permeability and then it is heap leached. Fines are sent to agitated vessels for acid leaching, and the pulp from this operation is diluted by pregnant solution from the heap leaching.

Jan 10, 1979

By William H. Love

ATLAS shaft was sunk to explore at depth a portion of the eastern end of the dry belt, or silver belt, of the Coeur d’Alene mining district. The Atlas mine is a mile east of Mullan and is on the south side of the Osburn fault. Equal partners in the venture are Hecla Mining Co., Newmont Mining Co., New Jersey Zinc Co. and Atlas Mining Co., the financing being equally shared by Hecla, Newmont, and New Jersey Zinc. As outlined the project had as its goal deep exploration of prominent structures developed in the Atlas in upper levels. Plans called for deepening the shaft from the 800 level to the 2400 level with subsequent drifting, crosscutting, and diamond drilling on the 2400.

Jan 11, 1954

By Roger L. Winter, Borje O. Saxberg

Some form of wage incentives has been used traditionally in the mining industry to determine miners' pay. However, very little is actually known about the administration of such wage incentive plans in mining. As far as the authors know this is the first time a general examination of wage incentive systems as applied to underground mining has been undertaken.* This article reports the results of an investigation pertaining to the administration of wage incentive programs for miners who drill, blast, and load- mainly in underground metallic mining operations. This investigation was conducted to obtain management's views and attitudes towards wage incentives; therefore, the results do not necessarily represent accurately the thoughts of the miners themselves nor those of any organized union of miners.

Jan 10, 1960

By Frank J. Anderson

IN the cement region of the Lehigh Valley, a difference of 2 to 3 pct in CaCO3 can make or break a new quarry development, and experience of the Dragon Cement Co. has shown that values of calcium carbonate, as reported from churn drill samples, have been increased as much as 6 pct on the average when the same area was diamond drilled. This calcium carbonate increase consequently lowered the values for silica, iron, and alumina, and made these sections much more attractive. Since 1950, the Dragon Cement Co. Inc. has been engaged in extensive diamond drilling in the local limestone of the Northampton, Pa., region, known as the Jacksonburg formation, and in the Lebanon, Pa., region in the Annville limestone, both of Ordovician age.

Jan 12, 1954

I have attended these meetings, every year, since 1926 and have served on both the Pittsburgh and the National Executive Committees, so that I am fully aware - of the ruling of this organization regarding, "No Papers by Vendors". Since I am now classified as a VENDOR, I wish to express my sincere appreciation for the invitation to formally discuss these very interesting papers --all of which herald the coming of an entirely new era in the manufacture of quality steels. I also appreciate the references by Mr. Mosser and Dr. Swinkels to my first paper on the oxygen probe which was presented at the meeting of this group, here in Chicago, in 1966 and was subsequently published in the NOH Proceedings of that year. (1)

Jan 1, 1972

By R. G. Robins

The processing of gold bearing sulphide minerals which contain arsenopyrite and various complex arsenic sulphides results in arsenic containing emissions and effluents which are suspect in relation to clean air and clean water standards. Removal of arsenic from gaseous emissions is briefly reviewed. The use of lime to stabilise aqueous residues as either calcium arsenate or calcium arsenite is shown to be inadequate for long term disposal since both compounds are converted into calcium carbonate due to the influence of carbon dioxide in the atmosphere. Mixed calcium arsenate-phosphate residues are similarly unstable, but present better stability than the straight calcium compounds. Alternative disposal methods are reviewed whereby the arsenic is converted to more stable compounds, such as barium arsenate, titanium (IV) arsenate, and arsenic sulphide.

Jan 1, 1984

Chester Wells Purington was killed at Yokohama on Sept. 1, 1923, in the Japanese earthquake. Mr. Purington was born in Boston, Mass., Oct. 27, 1871. He prepared for his entrance to Harvard at the Boston Latin School and graduated from Harvard in the class of '93. He started out soon thereafter investigating gold deposits of the Appalachian system in the South and in 1895, made atrip to Alaska, investigating the gold deposits of that territory. The summer and fall of 1896 found him in the San Juan country of Colorado examining the gold and silver properties in the Telluride and Rico districts and in the La Plata Mountains. In the meantime, he had served on the economic staff of the U. S

Jan 1, 1924

The recent dedication of Magma Copper Co.'s San Manuel, Ariz., electrolytic copper refinery and rod casting plant marks the culmination of a three year, $250 million expansion-modernization program. The new facilities will eventually permit an annual production of 200,000 tons of marketable copper for direct sale to fabricators. The Newmont Mining Corp. subsidiary will produce and market continuous cast 5/16 in. copper redraw rod, full plate cathode copper and sheared cathode plate under its own brand name. Among the four largest in the nation, the new refinery and plant, was built at a cost of $34 million and will be fully automated. In addition, all materials used in the plant will be recycled and no waste, discard or emissions will occur.

Jan 3, 1972

By Shosei Serata

Conventional roof bolting may be giving ground to a new technique that utilizes only the ground itself to stabilize mine openings. This newly developed stress control technique (SCT) has initially been used in sedimentary ore bodies that are both overlain and underlain by weak strata. The technique is also suited to the design of production panels and main entry systems, and is readily adaptable to room and pillar as well as total- extraction mining, including both shortwall and longwall coal mining. In applications where the technique has been used, the requirements for roof bolting and floor renewal were virtually eliminated. The SCT comprises three basic methods and covers a wide range of problems associated with failing roofs and heaving floors in underground mines (see Table 1).

Jan 5, 1976

By William E. Ford, Edward Salisbury Dana

The Niobates (Columbates) and Tantalates are chiefly salts of metaniobic and metatantalic acid, RNb2O6 and RTa2O6; also in part Pyroniobates, R2Nb2O7, etc. Titanium is prominent in a number of the species, which are hence intermediate between the niobates and titanates. Niobium and tanta¬lum also enter into the composition of a few rare silicates, as wöhlerite, låvenite, etc. The following groups may be mentioned: The isometric PYROCHLORE GROUP, including pyrochlore, microlite, etc. The tetragonal FERGUSONITE Group, including fergusonite and sipylite. The orthorhombic COLUMBITE Group, including columbite and tantalite. Also the orthorhombic SAMARSKITE GROUP, including yttrotantalite, samarskite, and ånnerodite. The species belonging in this class are for the most part rare, and are hence but briefly described.

Jan 1, 1922