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By D. P. Bryan

The identification and-develop¬ment of new construction aggregate resources, the most common mineral mined, is an essential need in this country's growing urban areas. In developing an aggregate exploration program, a thorough geological identification of all potential aggregate resources in an area is still of primary importance but other factors have also to be considered. These include physical properties, end product application, transportation and mining costs, and local government regulations including zoning. The present major aggregate producers are most likely to develop these future resources and are in the best position to initiate comprehensive exploration programs.

Jan 1, 1987

By D. W. Frommer

In continuing its long range studies of methods of treating low-grade iron ores, the Bureau of Mines has developed a new selective flocculation, desliming, and flotation procedure that enables effective beneficiation of the finely disseminated ferruginous jaspers of the Marquette range, Mich. The process, developed on a bench scale and later confirmed in the 800-lb/hr pilot plant, comprises dispersion, selective flocculation, desliming to reject fine silica and clay, and flotation of silica from the remainder of minus 400-mesh pulps. Pilot plant flotation of two Marquette range ores, using the selective flocculation procedure on feeds containing 36 percent Fe, yielded iron recoveries of about 84 percent in concentrates containing 65 to 66 percent Fe and 4 to 5 percent silica. These results were metallurgically superior to those obtained when selective flocculation was not used. Also operating characteristics were better, and reagent costs were lower.

Jan 1, 1964

By Lynn B. Hales, Randy A. Ynchausti

Expert supervisory control strategies have been used for many years to improve operating revenues in comminution circuits. Typical improvements in capacity range from four to eight percent. Several case studies of results will be presented as well as a general discussion of the technologies used to achieve the improvements. Crushing. SAG milling and ball milling circuits will be discussed.

Jan 1, 1997

By Arthur W. Darby

Heathrow Airport is owned and operated by BAA who are engaged in a major programme of expansion. In order to link the expansion of the airport in the west with the existing central terminal area, a twin bore, 8.8m outside diameter, road tunnel,1280m long, is being constructed. The tunnel drives pass over, with limited clearances, an operating railway tunnel, and pass under, with about one diameter cover, the airport taxiways and aircraft stands. Selection of the machine was heavily influenced by the need to minimise settlement.

Jan 1, 2003

By T. Vincze

Effective coal mine face ventilation, for remotely controlled and automated mining systems, is essential for the control of methane. The evolution of new mining equipment and methods has required changes and improvements in face ventilation methods. One emphasis today is on the use of remotely operated and automated mining systems that can be used to make continuous cuts of 6 m (20 ft) and deeper. U.S. Bureau of Mines research is studying ways to more effectively ventilate these extended cuts. Two face ventilation techniques that utilize either blowing brattice or a jet fan for deep cutting are examined in this paper. Bureau of Mines procedures for evaluating face ventilation systems are also discussed.

Jan 1, 1992

By Ronald S. Conti, Harry Dobroski

Re1iabl e monitoring a1ong an underground mine belt line is of great concern because of combustibles, electrical apparatus, and friction. Belt entries are strategically located where a fire can have rapid and disastrous consequences. This paper reviews conventional distributed temperature sensing systems based on resistive, thermistor, and thermocouple effects. These are shown to provide limited benefits. A new system tested by the U.S. Bureau of Mines based on fiber optics and time domain reflectrometry, promises much better temperature and spatial resolution, faster response, inexpensive cable, longer distance, and comprehensive data analysis. Test results in a small, controlled, in-mine fire are given.

Jan 1, 1992

By F. Kennedy

Consolidation Coal Co. (Consol) supports an active research and development effort to improve the safe, productive mining of coal and to use coal in an environmentally acceptable manner: Attention will be focused on degasification of coal seams, continuous coal transport systems, earth sciences activities, and coal combustion. Brief mention will be made regarding the SO2 emissions control programs. The research program constitutes about 1 % of Consol coal sales, which positions Consol as the preeminent coal company supporting broad-based research addressing the full spectrum of the various problems associated with using the nation's abundant reserves of economical, readily available fuel.

Jan 1, 1990

By R. L. Unger

Restricted fields of vision are a common problem with underground mining equipment. Also, when lighting systems are provided, they may be positioned where they cause glare. This restricts the visibility around the machines even further. To help address these problems, the US Bureau of Mines has developed a PC-based software package to aid in the analysis of certain human engineering aspects of mining equipment design. The software is available for use by equipment manufacturers and mining companies for design work on new machines, as well as for evaluating proposed modifications to existing machines.

Jan 1, 1995

By Alexander B. Ikonnikov

All known bauxite deposits in China occur in its eastern half, and almost all of them are found in the Carboniferous and the Permian. They are of platform origin, but contain diaspore as the major ore mineral. There is only one known deposit composed of gibbsite. The most valuable deposits are sedimentary ones formed in local depressions on the edges of platforms during marine transgressions. They lie on Upper Cambrian or Middle Ordovician limestone that was weathered for a long period of geological time. Generally, Chinese bauxites are low in iron, and have a rather low alumina/silica ratio.

Jan 1, 1984

By Timothy M. Dyhr, Marie Garrett

The Cannon Mine gold project has been perceived as unique for being developed in an area characterized by orchards and suburban residences. The Cannon Mine was permitted and developed successfully in this setting. However, the ability of companies to permit, develop and operate mines in mated areas is becoming more difficult as a result of opposition by residents and increasingly stringent regulation. The challenge to the mining operator in the future on otherwise economically attractive mineral deposits will be the ability to explore and develop these types of projects successfully and cost- effectively

Jan 1, 1987

By Boleslaw Tolwinski

This paper presents an algorithm for the de- termination of a production schedule for an open pit mine that satisfies all principal physical and economic constraints required by a realistic mine design. We propose to model the evolution of the mine over time as a sequential optimization problem or, equivalently, as a problem of finding a path with a largest value in a graph. Some preliminary evidence is provided that such a path can be effectively sought by an algorithm that combines a number of heuristic search rules, inspired in part by learning theories developed in Artificial Intelligence.

Jan 1, 1992

By Li Changgen, A. Bahr

The adaptability of pneumatic flotation cells for the flotation of sulfide ore and the conditions for sulfide ore flotation in pneumatic cells were investigated. The advantages of pneumatic flotation cells over mechanical flotation cells, as well as flotation columns, for the flotation of sulfide ore were demonstrated. Test results indicated that the Cu grade and recovery for concentrates obtained when using the pneumatic flotation cell were 1 % to 2% and 4%, respectively, higher than those obtained when using the mechanical flotation machine.

Jan 1, 1993

By J. A. Nelen, R. B. Cook

Panned stream-sediment, geochemistry-based gold exploration in those parts of the southeastern Piedmont proximal to the Fall Line must take into account potential contamination from basal fluvial sediments of the Coastal Plain. Anomalies attributable to the incorporation of placer gold of Coastal Plain origin into modern Piedmont drainages have been identified in portions of Lee, Macon, and Tallapoosa Counties, AL, and Baldwin and Hancock Counties, GA. Identification and interpretation of such multicyclic anomalies must be based on knowledge of the local maximum Cretaceous transgression, paleotopography, modern and paleofluvial system dynamics, and fineness trends and Au-Ag zoning in gold grains.

Jan 1, 1990

By J. Kalnejais

Discovered in 1896, the Sons of Gwalia orebody was initially mined by unground methods. Euring the mine's uderground operations workings reached a vertical depth of 1080 metres. The same orebody is now being mined by open cut methods. The present operation mines a broad envelope of mineralisation surrounding old stopes, whereas the original underground operation concentrated on mining high grade parts of the Gwalia Lode System. Underground mining continued up to 1963 when operations ceased due to high operating costs and the low grade of ore mined. In 1984 a new company, Sons of Gwalia NL, commenced open cut operations.

Jan 1, 1989

By A. S. Astakhov

Working out of the production calendar plans (schedules) at deep mines which provide for the interaction of all kinds of mining operations determining coal output growth and mining and technical indices is a striking example of mining art. However, multi-variant decision making, a sophisticated system of integration, as well as high labour consumption for calculation and graphic operations in calendar planning require the improvement of traditional techniques and the development of new methods for calendar planning of mining operations at deep mines. The following specific aims were pursued in developing a computerized system of calendar planning (scheduling) of mining operations.

Jan 1, 1979

By J. Hanna, I. J. Anazia

The Mineral Resources Institute (MRI) has developed a unique process for selective fatty-acid flotation of phosphate minerals from siliceous ores. The process takes advantage of preferential adsorption (over silica surfaces) and high reactivity of fatty-acid collectors toward apatite under slightly acidic conditions (pH 5 - 6.5). The process was successful in upgrading various Florida and North Carolina phosphate samples containing 7.7% to 15.3% P205 and 62.3% to 77.2% siliceous gangue (Insol). The resulting concentrates assayed 28.1 % to 33.1 % P205 and 4.1 % to 9.9% Insol, with high P205 recoveries of 81.8% to 92.2%. Depending on the degree of surface contamination of the silica particles in the flotation feed, one or more cleaning steps, with or without sodium silicate, would be required to achieve higher-grade phosphate concentrates.

Jan 1, 1994

By Raymond S. Shrode

Limestone and dolomite production is of significant importance to the Baltimore and Ohio Railroad. Except for coal, more tons of limestone and dolomite are moved by the Railroad than any other mineral raw material. In the territory served by the Railroad, these materials are produced from every geologic system from Cambrian through Pennsylvanian. Some of the operations produce premium stone acceptable for high-specification steel and chemical use; at others, the stone finds application as aggregate materials and for cement manufacture. The Railroad is interested in seeing continued production from the operations it now serves, and in serving operations in a way mutually beneficial to the Railroad and to the producer. In working with producers, the importance of geologic knowledge in prospecting and development of deposits has been clearly recognized. In turn, knowledge of the economic and technological facets of production and consumption is needed for the geologists to participate with maximum efficiency.

Jan 1, 1966

By J. Alvarez, S. H. Castro

The feasibility of chalcopyrite-pyrite separation in the flotation of a chalcopyritic copper ore, at reduced surface tensions regulated by methanol, was investigated. It was found that with methanol dosages from 0.5% to 1.5% v/ v, the chalcopyrite might be effectively separated from the pyrite, without use of other flotation reagents and pH regulators. However, under this simple condition, the chalcopyrite recovery was only around 50%, recommending the use of other reagents to reinforce the collector action. Low dosages of different collectors were tested, including SF-323 (Shell Float), S-6588 and S-7251 (Cytec), and S-701 (Molycop). Very promising results were obtained with low dosages of the collector S-701 and 1% v/v of methanol in the pulp, which evaluated against a reference test, gave similar copper recovery, higher Mo recovery and higher depression of pyrite. Consequently, this is an alternative process which does not require the use of lime to depress pyrite.

Jan 1, 1995

By M. J. Hrebar

A study was conducted to evaluate the applicability of large wheel loaders (Caterpillar 994 Class) for use as primary loading equipment in open pit iron-ore operations. Field visits were made to taconite and gold mines that used large wheel loaders. Information was gathered on loader selection rationale; operation and maintenance experience; and production, availability and costs. Brief time studies were conducted to indicate machine performance and utilization. This paper summarizes the field data that was collected including an economic comparison of wheel loaders and cable shovels in an iron-ore application.

Jan 1, 1997

By Jorma Miettunen

The Plant. The annual production of the Pyhasalmi mine is 900 000 tons of copper- zinc-pyrite ore containing approximately 0.7 % Cu, 2.5 % Zn and 30 % S. During 1976...1981 altered surface ore, 850 000 tons in all, was also treated at the concentrator. The surface ore was crushed and ground in a separate plant and was then fed into the copper or zinc flotation or was flotated in its own circuit, depending on the degree of alteration and the content of copper and zinc in the ore. The surface ore was exhausted in October 1981. Flotation comprises three consecutive flotation circuits; copper, zinc and pyrite circuit. The zinc circuit includes an open circuit roughing and scavenging. The scavenger concentrate and cleaner tailing are pumped to the middlings flotation. Rougher concentrates of the open circuit and the middlings flotation are pumped to cleaning which includes four stages. Figure 1 describes the flowsheet of the zinc circuit.

Jan 1, 1982