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By Carl R. Davis

The cost of mining during the past history of these mines has been excessive, principally by reason of the inefficiency of labor under the wage-system. The amount of labor performed per man was unsatisfactory; and Mr. Edmund B. Kirby, the general manager, decided to adopt the contract-system as a remedy. For this purpose the method now in use was devised by the writer (then and now the superintendent), as best adapted to the local conditions. On March 12, 1900, this system was presented to the miners of the War Eagle and the Center Star. The issue remained unsettled for several weeks,

Jan 1, 1902

An informal meeting of the Conferees of the Development Committees of the four Societies was held in New York on July 2, 1919, at which the scope of the work was considered, and a sub-committee oil Procedure, consisting of the chairmen of the Conferees from each of the four Societies, was appointed to arrange the program for and the time and place of the first formal meeting. The Conference subsequently adopted the name, " The Joint Conference Committee." The Joint Conference Committee convened at the Hotel Montclair, Montclair, N. J., Aug. 13, 14, and 15, and in New York, Sept. 15, 16, and 17, 1919. The Committee has divided its report into two parts, that covering the public activities and that covering the society activities of common interest to the four societies.

Jan 12, 1919

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 R. A. Wyman

The overall approach to nonmetallic mineral flotation practiced in the laboratories of the Mines Branch, Ottawa, Canada, is outlined. The use of floatability tests to indicate possible areas of selectivity is indicated. Selected examples of the evolution of flotation systems are presented. Reagents are briefly discussed.

Jan 1, 1972

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 George Schore

Radiation grafting of ion exchange structures contains ion exchange groups but may consist of neutral groups. High energy grafting of monomers on to polymers has-been known since 1950 (1.2); manufacture on an industrial level was-begun in 1970.(3) Proper choice of substrate and monomer will produce various ion exchange membranes with differing physico and chemical properties. Grafting a selected monomer to the proper polymer will provide selective ion exchange with assured chemical protection of the substrate. Ion exchange systems utilizing radiation grafted structures to polymers have been fabricated to "capture" gold from drag-out and rinse water and silver from cyanide rinse water. Other ion exchange systems can feasibly be produced to remove other precious metals. Rotating Cathode Technology is used to recover the metals from their concentrated eluating solutions as pure metal foil.

Jan 1, 1984

By W. F. Burns

(Butte Meeting, August, 1913.) ATTEMPTS were made in 1908, at the Great Falls Works, to produce ingots direct from the Butte precipitate by smelting the material in a reverberatory refining furnace. The ingots produced in this manner averaged 99.4 per cent. of copper and 0.40 per cent. of arsenic and antimony. The copper content being considered too low, it. was decided to cast the copper into anodes and to treat the anodes in the electrolytic plant. No. 1 Furnace, in which the precipitate was treated, was a regular cathode refining furnace previously employed in making wire bar, cake, and ingot from electrolytic cathodes. The hearth of the furnace was 24 by 12 ft., having a capacity of 100,000 lb. of cathodes. The furnace was coal fired, and the copper was dipped by means of trolley ladles.

Jan 7, 1913

By Charles O. Thompson

In 1867 the city of Worcester walled in the Mill Brook for its main sewer. This stream, one of the important affluents of the Blackstone River, flows through the city in a southwestenly course from Salisbury Fond, and along its valley a considerable part of the heavy manufactories of the city are placed. At two points, a mile apart, a sufficient fall occurs to be turned to account for motive power, and at many points it was the right and practice of the riparian proprietors, prior to 1867, to use the water for steam and other manufacturing purposes. But the

Jan 1, 1881

By Wm. Wallace Mein

IN March 1949 the Calaveras Cement Co. was sued by five landowners whose properties are located in the vicinity of the plant. These landowners-all of them cattle ranchers-sued for dust damages of $120,338 and for an injunction preventing the company from casting dust upon their properties in injurious quantities. The issue was split, the jury deciding the amount of damages and the court handling the injunction features. The action came to trial before a jury in April of that year and resulted in damages being awarded in the amount of $7,508. A month later the court issued its injunction requiring recovery of stack dust to an 87 pct minimum.

Jan 6, 1951

By J. F. Labuz

Fracture tests were conducted on subsize specimens of Charcoal granite to demonstrate that the extent of the nonlinear region at the crack tip can be significant. The model of the fracture process considers an effective crack length as a traction free portion plus a process zone where closing stresses act; this zone is identified by microcracking and interlocking. A singularity is allowed at the effective crack tip. The effective stress intensity factor is the superposition of the stress intensities due to the effective crack and the process zone. By assuming that the closing stress is a linear function, it is shown that a process zone length of approximately one-third the effective crack is needed to match the compliance-determined crack length.

Jan 1, 1984

By N. S. Keith

Some time ago, a firm engaged largely in the manufacture of copper sulphate, applied to me for information as to the practicability of obtaining the copper from their mother liquors by means of electricity ; having reference, more especially, to obtaining the electric current from some magneto-electric or dynamo-electric machine. The mother liquors were the result of several solutions of commercial scrap copper, containing impurities, the quantity of which

Jan 1, 1879

By R. J. Shaffer

Hydraulic fracturing in rock masses involves complex and coupled processes of fractures propagating in discontinuous media and of fluid flow in discrete channels. The Unconventional Gas Program at LLNL is actively developing numerical models to gain insight in the physics of these coupled processes. This paper describes the current status of the FEFFLAP code, which models fluid-driven discrete fracture propagation in jointed media. We also discuss the results of a preliminary series of physical tests in which hydrofractures were driven across slanted interfaces between dissimilar materials, in blocks loaded in biaxial compression.

Jan 1, 1984

By Ralph H. Sweetser

When a furnace-manager is '(blowing in," he generally has no time to consider the composition of the waste gas, and does not bother with it, except to take care that he does not get " gassed." Moreover, the analysis of the gases while the wood is still burning has not much to do with the economy of the normal working of the furnace; yet, on account of the deadly effects of the " blowing-in " gas when inhaled, and of its high explosive qualities, it is interesting to know its composition. In the Transactions there is no record of the analysis of the gas during an up-to-date " blowing-in." Even in Mr. Whiting's admirable paper (Trans., xx., 280) the reported analyses did

Jan 1, 1899

By R. W. Raymond

THE death of Louis Janin, which took place Mar. 6, 1914, at Santa Barbara, terminated the earthly career of almost the last survivor, and one of the most illustrious, members, of that group of American mining engineers and metallurgists who, in the last quarter, of the nineteenth century, directed the development of the mineral resources of the Pacific slope. Louis Janin was born in 1836 at New Orleans. His grandfather, an officer in the French army, had emigrated to this country, with his family, at or before the outbreak of the French revolution. His father became an

Jan 7, 1914

By F. R. Morral

HOT-DIPPED heat-treated zinc coatings on sheet steel were examined with X-rays. The phases identified were compared with those listed in the modern literature of the zinc-iron system. The zeta (FeZn13) phase is shown to correspond to the phase found by Schueler (1925) in heat-treated zinc coatings. An investigation was undertaken to determine the phases present in hot-dipped FIG. I.-SYSTEM IRON-ZINC ACCORDING TO J. SCHRAMM.11 heat-treated zinc coatings on steel sheets and wire. This kind of coating on wire was studied some years ago by Schueler1 by microscopic and chemical methods. He reported a new phase, FeZn10. Later, Clark and Stillwell,2 using X-ray crystal analysis, identified a new phase in ordinary galva-nized wire, which was assumed to be the FeZn10 phase.

Jan 1, 1940

By H. S. Geismer

There are three general methods available for obtaining commercial brown iron-ore: hand-screening; washing; and washing and concentrating. Hand-screening has produced a large tonnage of ore in the past, but is rapidly falling into disuse, except as a preliminary step, largely because modern furnace-practice requires all forcigii material to be separated from ores before they are deliv-

Jan 1, 1912

By Thomas A. Earl

Much of the strip mining in the Appalachian coalfields was done prior to backfilling and regrading requirements, resulting in many devastated areas which also have serious acid mine drainage problems. Economic incentive or justification for reclaiming these thousands of acres of land does not exist unless some value can be attached to the open cuts and weathered overburden piles. In Pennsylvania many of these old strip mine cuts are being successfully used for sanitary landfills and sludge disposal sites, and multiple benefits are realized. Given proper regulatory control, this technique could be beneficially applied to many other areas in the east.

Jan 1, 1977

By F. M. Sandoval, R. E. Ries, J. F. Power

Returning the original soil material to the surface of smoothed mine spoils is a practical means of restoring agricultural productivity. Research has established that high-sodium spoils in North Dakota: (1) must be covered with about 70 cm of soil material to achieve maximum production; (2) top-soil must be segregated and spread separately from subsoil; (3) potential production depends on the quality of the soil material returned; and (4) erosion and upward salt movement must be controlled for sustained production. Erosion is best controlled by reducing final grades as much as possible during the smoothing process followed by prompt establishment of vegetation.

Jan 12, 1979

By W. Arthur White

Underclay squeeze is the plastic flowing of underclay below coal pillars into mined-out entries and rooms. Squeezes may be caused either by wet mine conditions where the moisture is taken up by the clay-making it more plastic-or by the presence of certain clay minerals, such as mont-morillonite, which are plastic when there is enough natural moisture. Under either condition, sufficient stress will cause the underclay to flow. Squeezes may fill an entry or room within several hours, or it may be several months before movement stops. Squeeze areas commonly cover hundreds or thousands of square yards.

Oct 1, 1956

By E. A. H. Tays

At the present time, the mine-owner has a number of patent crushers to choose from, when contemplating the erection of a mill; and a number of new ones are yearly brought to notice. We all know that the stamp-mill is the old standard; but several of the patent crushers, especially of the roller-type, are not without their merits. Having had a working experience, extending over a period of four years, with the " Bryan roller quartz-mill," working alongside of stamp-batteries, I take pleasure in giving to the members of the Institute the benefit of my experience with this mill.*

Jan 1, 1900