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By Boris M. Vorobjev

The paper in question discusses a wide range of topics related to computerized coal mine monitoring systems starting with the history of development and application of computerized monitoring coal mine systems and finishing with modern trends in the design and updating of such systems. The paper focuses exclusively on methodological and technical aspects of computer-based coal mine monitoring systems and their applicability in both surface and underground coal mining operations.

Jan 1, 1989

By Mark A. White

Surface mining of multiple seams by mountaintop removal and contour mining is complex in Appalachia. Arch of West Virginia, a division of Apogee Coal, has made its operations state-of-the-art to cope with this challenge. Arch of West Virginia moved into the heart of coal mining in Appalachia when Arch Mineral acquired coal reserves and coal operations in the southern West Virginia counties of Logan and Wyoming. These reserves were initially developed at the turn of the century as underground operations. Today, though, they are mined using mountaintop removal and contour mining. The steep slopes in the mountains of Appalachia generated a method of mining referred to as contour mining. During the late 1960s and early 1970s, contour mining was introduced at these operations using front-end loaders with bucket capacities of more than 7 m3 (10 cu yd) that could load 45-t (50-ton) end-dump trucks.

Jan 1, 1995

By J. Kelleher, R. Saulters, K. H. McDaniel, L. Griswold

To improve underground safety and visibility during mining applications, the Waste Isolation Pilot Plant designed and built a dry-dust filtration unit. The unit works in conjunction with a Spendrup 1120-70 fan with ventilation tubing to filter the face exhaust air during mining operations. The closed- loop system is designed to filter 17 m3/s (36,000 cfm) and is intended to screen 10- µm (1,250 mesh) and larger particles at 90% efficiency. To accomplish this, the unit uses a combination of Dollinger Staynew Inertial Spin filters, cyclones and traditional mesh filter media.

Jan 1, 2002

By James W. Martin, Brad H. Droegmiller

As construction projects continue to get larger, greater demands are placed on systems to provide higher production rates at reasonable costs. This paper shows the application of dozer-trap loading versus other methods of moving bulk materials. Most conventional methods employ multiple types of heavy equipment to accomplish a single task. Trap loaders fed by dozers and discharging onto overland conveyors offer an alternative/economical means of high volume bulk material movement. This paper will discuss the process of trap loading to overland conveyors.

Jan 1, 1998

By W. K. Tolley, D. G. Kotlyar

Silver is an economically important component of many complex, massive sulfide ores. The beneficiation of this type of ore is now almost entirely accomplished by flotation. Silver recovery is often low, and little is known about the flotation behavior of the silver-bearing minerals. Floatability studies were conducted using silver-bearing tetrahedrite and lead-zinc ore. The effects of xanthate-collector concentration, conditioning time, potentiostatic control of the mineral potential and control of the pH on mineral floatability were evaluated. The floatability of the silver-bearing minerals was shown to depend on collector concentration and mineral potential. The effect of controlling the mineral potential during the flotation process is discussed.

Jan 1, 1996

By Robert C. Freas

The summer joint meeting of the East Tennessee and Carolinas Sections of SME was held in Morristown, TN, on July 29 and 30, 1994. The Friday portion of the meeting began with a field trip to Asarco Inc.'s Young Mine and Mill, one of four mines operated by the company in the Mascot-Jefferson City district. The Young Mill processes ore from two other mines as well as its own, first by heavy media separation and then by standard flotation processes. Zinc concentrates are shipped by truck and barge to an electrolytic refinery in Clarksville, TN. The heavy media rejects and the dolomitic limestone tailings are sold through Asarco subsidiary American Limestone Co. Saturday's technical session, organized by Program Chairman Bob Fulweiler of the Tennessee Division of Geology, provided a review and status report of the zinc industry in Tennessee. This article summarizes papers presented, including one on recent developments in underground blasting.

Jan 1, 1994

By G. D. Hood, B. E. Davis

A fundamental study of the mechanisms involved in the conditioning of coarse Florida phosphate has led to some interesting discoveries. Studies by the US Bureau of Mines have shown that conditioning time and mixing intensity greatly affect the grades and recoveries of the phosphate minerals and quartz in the rougher concentrate. In particular, as the conditioning time or mixing intensity increased, the phosphate recovery remained constant while the amount of quartz floated decreased. This phenomenon is contrary to conventional wisdom and could lead to a more efficient coarse flotation circuit.

Jan 1, 1995

By Joe Maloney, Steve Shadow

Mining conditions at Cyprus Amax's Twentymile Coal Company (TCC) require the use of regenerative conveyors. Regenerative conveyors were first used in the Southwest Mine District and then in the challenging East Mine District. This paper will discuss the development and refinement of the equipment used to brake the regenerative conveyors.

Jan 1, 1998

By Greg Joachims

Composition of salt in the Permian Flowerpot Shale in northwest Oklahoma suggests that the salt in this formation was deposited in the early phase of solar evaporation. Brine produced through natural dissolution of the subsurface salt has netted very pure brines, with relatively low concentrations of magnesium salts that should result from late-stage precipitation of salt deposits from sea water. Over the last 100 years, extensive studies of sea- water evaporites, in relation to brine density, have been a topic of discussion. The development of evaporation models has facilitated the increased production and purity of solar salt (salt produced through evaporation of brine by the sun's energy). Conversely, this information can be utilized to gain an understanding of how rock-salt formations were precipitated from sea water by analyzing the elemental constituents of the rock salt and of the resulting brine. By evaluation of well-documented, phase-curve tables of sea-water evaporation, a basic theory can be formulated on how the Flowerpot salt unit was formed.

Jan 1, 1999

By S. K. Kawatra, T. C. Rao, J. P. Barnwal, Durga D. Patil

Coal macerals differ widely in their surface properties and in their hydrophobicities. Therefore, it is necessary to study the flotation time dependence of coal macerals using varying concentrations of various frothers and collectors. In the present study, froth flotation is used to explore the possibility of segregating coal macerals based on their relative rates of flotation. Petrographic analysis of the various macerals in the concentrate were carried out, and the results are expressed in terms of the recoveries of various maceral groups and mineral matter. Results show that it is possible to recover a good volume of the reactive macerals without mach loss of calorific value.

Jan 1, 2000

By Jim Avraamides

Historically, much of Western Australia's gold production has come from the refractory sulphide-telluride ores located in Kalgoorlie's Golden Mile. Most of the recent gold boom has been associated with low grade, open pit free-milling oxide deposits. Primary sulphides are commonly encountered at depth and in many cases are highly refractory. Different approaches to the problem of recovering go1d from these ores have been adopted subject to local conditions both technical and environmental. The least preferred option is the preparation of a gold- rich flotation concentrate which is shipped to a smelter. Roasting of flotation concentrates can be practised in certain remote locations where sulphur emissions are tolerated. Fine grinding of flotation concentrates followed by direct cyanidation is another popular approach although this often leads to fouling of carbon by flotation reagents in the adsorption section and high soluble gold losses.

Jan 1, 1989

By Don L. Jensen

With the successful implementation of supervisory control on the Bagdad concentrator grinding circuits, steps have been taken to expand supervisory control to the flotation circuits. This paper discusses the design and installation of the slurry delivery systems, analyzing instruments, level control devices, reagent pumps and supervisory software. Emphasis is placed on the design and installation of a reliable slurry transport system to feed the Courier 30 online analyzing instruments. Total system availability has been measured at plus 95%. Phase 1 acceptance testing of the supervisory software indicates a notable increase in copper recovery with no significant change in final copper grade.

Jan 1, 1999

By B. K. Mishra, Partha Chakroborty

Jigs are the most important equipment used in the separation process that exploits the stratification of particulate matter under the influence of hydrodynamic and gravitational forces. Very little is known about the determined mechanisms by which particles of varying density, size, and shape stratify in a moving bed. A model is developed by using the discrete element method to understand the behavior of jig bed. This model is utilized here to study the stratification behavior of the bed and its control. The control action is based on the understanding of the physics of the stratification process within the framework of fuzzy logic. The actions suggested by the fuzzy logic controller (FLC) depend on the current degree of stratification and the existing frequency of the jig cycle. The results show that the FLC achieves efficiency in stratification with minor variations to the jig cycle.

Jan 1, 1995

By Ronald J. Allain

Water soluble polymers play an important role in many industries. The mining industry is dependent on these materials to help accomplish many solid-liquid (water) separations. Mechanical devices alone are not capable of achieving the degree of separation needed. Mechanical and chemical separations act in concert to accomplish the necessary separation. The history of the use of water soluble polymers has gone through several evolutionary phases and I believe we are facing another of these phases. At first, various natural products were common - starches, gums, and various polysaccharides. These were replaced by the synthetic polymers based on copolymerization of various vinylmonomers mainly in conjunction with acrylamide. The use of these polymers and their needs continues to grow. This paper will cover a brief overview followed by a look at the future of water soluble polymers. A focus will be on applications of water soluble polymers in the mining industry.

Jan 1, 1994

The authors give a corrected form of the Korobov algorithm of optimal open pit determination and describe a method of optimising the mining sequence within a preliminary pit design. A method of automatically including roadways is also given.

Jan 1, 1992

By D. Doepker

The dissolution of metals from various metal/ non-metal mine tailings has been studied through column leach tests at US Bureau of Mines laboratories. Metal mobilization in unsaturated columns was consistently greater than metal dissolution in water-saturated columns. Leachate pH was also frequently lower when a leachant was passed through columns but showed a mixed residence-time dependence. On the other hand, metal and sulfate ion concentrations in the leachate increased with dry-cycle residence time. Results suggest that acid formation through atmospheric oxidation of pyrite may compete with non-acid-forming oxidation of other metal sulfides. The two processes lead to decreased pH and increased metal mobilization, respectively. Leach tests using sodium lauryl sulfate indicated that microbial activity was not a factor in these studies.

Jan 1, 1991

By H. T. Miller, L. M. Scott

Radiation exposures in Uranium operations may result from external beta-gamma radiation emitted by Uranium and its progeny, internal exposure to alpha and beta radiation due to the inhalation and ingestion of Uranium ores, Radon gas, and Radon progeny in mine, mill, and laboratory atmospheres and from the contamination of environmental working surfaces and clothing by Uranium-bearing compounds and ore. This paper summarizes occupational experience with reference to the exploration, surface mining, underground mining, milling and transport of Uranium by one company in the U.S. and Canada.

Jan 1, 1981

By R. Asmatulu

A method of improving the efficiency of solid-liquid separation during centrifugal filtration has been developed. It consists of increasing the pressure drop across the filter cake using extraneous means such as pressurizing a filter chamber. This method, which may be referred to as hyperbaric centrifugation, is designed to increase filtration rate during the drainage cycle and, hence, to produce drier cake. In the present communication, the results obtained in a series of batch centrifugal filtration experiments are presented. The results obtained on fine coal and mineral samples show that cake moistures are approximately 50% lower than the case of using ambient pressure.

Jan 1, 2004

By J. J. Schwoebel

Resource Enterprises Inc. (REI) is exploiting the coalbed gas resource by working in unison with active underground mining operations. At REZ7s pilot project at the Soldier Canyon mine, Carbon County, UT, RE1 has drilled nearly 15.25 km (50,000 ft) of horizontal in-seam and slant boreholes during the initial two years of drilling activity. Produced gas has been sold to a natural gas transmission company on a continuous basis since mid 1983.

Jan 1, 1988

By S. K. Singh, J. Shepherd

Feather-edging, a major source of injury and fatal accidents in Australia, South Africa and the United States, refers to a phenomenon in which the roof at the goaf edge falls, often suddenly, as a thin wafer of rock that overrides conventional timber breaker lines. The fall may adversely affect a working bord at a distance of 15 m (50ft) or more from the goaf edge. Feather-edging typically occurs in relatively massive, strong roof strata such as sandstone or conglomerate. This paper presents the results of a test in which a concentrated row of fully grouted bolts were used to prevent feather-edging in an Australian pillar- ("total-") extraction coal mine. The test demonstrated that the bolts could resist feather-edging.

Jan 1, 2000