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By W. A. Niepelt, F. A. Locher

Flow in steep cascades may lead to the occurrence of a nearly periodic train of waves known as slug flow. This, in turn, may result in overtopping of the channel walls and problems with energy dissipation in receiving sumps. Experimental data from an operating facility was used to extend clear water technology for predicting the occurrence of slug flow to conditions with slurry flows. A design methodology and a design chart to determine the region of steady flows is presented that will permit the design engineer to avoid slug flow in cascade systems for conveyance of slurries.

Jan 1, 1990

By Jan Wolski, Jack Barry

Ventilation ductlines with a single fan or with a series of fans are analyzed. The duct friction loss factors are discussed. Numerical solutions, presented in the paper, applies to any fan number and locations along a duct line. The findings are compared with formulas available in the technical literature. Values of the air leakage factors are presented in the SI, technical metric, and US unit systems. A method is shown of how to determine the leak- age factor for a given ductline. Optimum solutions for the sample duct lines with two and five fans in series are discussed and presented in a graphical form. Performance of fans in series is discussed in conjunction with both friction pressure loss and leak- age.

Jan 1, 1997

By C. L. Karr, E. J. Gentry

Researchers at the U. S. Bureau of Mines have developed a control algorithm to efficiently manipulate chaotic systems. The control, based on both fuzzy logic and genetic algorithms, prescribes actions that drive the chaotic system to acceptable regions of state space. The use of fuzzy logic enables a person who has limited experience with a chaotic system to establish a set of rules for manipulating the problem environment, and a set of membership functions that define terms used in the rule-set. Genetic algorithms are search algorithms based on natural genetics, and are used in the control algorithm to select membership functions that provide for a suitable level of control. The Bureau-developed algorithm controls the computer simulation of a ball bouncing on an oscillating table, a system that exhibits chaotic behavior.

Jan 1, 1993

By Y. C. Kim

This paper describes the implementational aspects of a blast hole kriging system that has been developedfor the purpose of daily ore/waste control in an open pit mine. The primary goal of blast hole kriging is to improve the ore/waste delineation procedure. A complete computer program package called Blast Hole Kriging (BHK) System was developed for IBMIPC AT or XT computers, using the Fortran language and supplemented by a few assembly language routines for the bit- map manipulation. This paper emphasizes the practical implementation requirements of the system and discusses system design considerations.

Jan 1, 1991

By Lee W. Abramson, Mee Shing Owyang

The Lake Merced Transport tunnel is 18 feet in diameter and 1.6 miles long constructed within dune sands, beach sands, and the Colma Sand Formation. It runs beneath highway right-of-way from an existing pump station near the shore of Lake Merced to a point near the Pacific Ocean, where it will connect with the existing transport/storage tunnel. The final tunnel lining was originally designed as a cast-in-place concrete lining to be constructed within steel ribs and wooden lagging initial support. The contractor opted to use a precast concrete segmental initial lining thus requiring a redesign of the final lining. The redesigned lining incorporates composite action from the initial lining thereby eliminating the need for outer steel reinforcement. A computer model was used for analyses which included operating conditions, ground and construction loads, and possible effects of liquefaction and earthquakes.

Jan 1, 1993

By Po-Wei Tun, Kuen-Yuh Wu, Tso-Min Shih, Hsi-Chiang Fang

The purpose of this study is to investgate the coal dust explosion characteristics and to search for the prevention methods of the coal dust explosion as well as the propagation of the explosion flame of the middle-bearing coal formation in Taiwan by an open type coal dust explosion apparatus in laboratory. The coal samples were taken from the typical middle-bearing formations of the Sam-Ming,Tai-Ho and Lee-Fong coal mines The rock dusts, the free water mixture with coal dust samples and the interval clean out the coal dust in the testing chambers were applied for preventing the coal dust explosion and the propagation of the explosion flame.

Jan 1, 1993

By Robert P. Larkin

The necessity for mineral extraction and its impact on man and the natural environment is a subject of increasing concern to Americans. Rising living standards and new demands for energy require increased mineral extraction, whereas the "new environmentalism" and concern over social well-being warn of the dangers to both the environment and the social system. This dilemma can only be solved by a complete understanding and analysis of all the factors relevant to human welfare which include environmental considerations, economic implications, and the social and psychological dimensions. A decision-making framework is therefore necessary which will encompass all relevant views of the problem.

Jan 1, 1975

By Henry P. Cole, Andrzej M. Wala

Engineers and psychologists at the University of Kentucky have developed simulation exercises that teach and test proficiency of mining technical personnel for coping with planned and accidental connections between separate air courses in underground mines. The exercises are based upon investigations of actual mine disasters. The exercises are judged as valuable and interesting training materials by experienced mining personnel. Although these specialists generally perform well on the exercises, potentially fatal errors are not uncommon. The use of such realistic exercises may better prepare miners for preventing and coping with underground mine ventilation emergencies.

Jan 1, 1987

By J. Van Kleunen

In the Spring of 1959 the Riverside Cement Company, a Division of American Cement Corporation, placed into operation at their Oro Grande California plant a new crushing-blending-reclaiming facility. This new facility, in conjunction with other modernization in the plant, has established a degree of automation and reliability on a-plant-wide basis which heretofore had not been attained in the industry. The blending and reclaiming facilities for raw stone and cement clinker at this plant represent not only the first computer programmed materials handling system of its type in the industry, but also the first installation of specialized equipment which was designed for high capacity, fully automated operations.

Jan 1, 1963

By Jack M. Jodrey, Neil D. O’Donnell, R. A. Metz

Bituminous sands of the Lower Cretaceous McMurray Formation in northern Alberta constitute the ore for the surface mining operation at Syncrude Canada Ltd. These sediments represent a complex succession of fluvial, estuarine and marine depositional environments. Grade prediction is realized through a combination of geological interpretation, computer modeling, and reference to past mining experience. Accurate forecasts of feed grade permit reliable predictions of volumes for removal to meet budgeted synthetic crude oil production. This planning facilitates efficient allocation of mining equipment and resources. The feed grade to the Extraction Plant is monitored at various points along the delivery system.

Jan 1, 1992

By A. T. Sapulek, C. S. Özveren, D. W. Dixon

The prediction of underground methane emission from longwall coal faces has been extensively researched for a number of years and numerous prediction methods have been devised. Many coal mines employ sophisticated environmental monitoring equipment which generates large amounts of data including, methane concentration, air velocity and barometric pressure. Presently this information is mainly used only to indicate alarm and danger levels of the monitored data for management purposes, however, the potential uses of this data are enormous[1]. This information could be used to good effect within a production/methane emission strategy as detailed in a previous paper[2]. The paper presents a practical application of artificial neural networks to underground methane prediction. Data on methane concentration and coal production has been obtained from an underground coal mine. The data is used in a neural network architecture and forecasts of methane concentration have been obtained. The forecasts are examined and there is a discussion of the potential use of the predictions from neural networks in the field of mining production control.

Jan 1, 1995

By Jozef F. Zurawski

The paper discusses design and construction of a 1.8 meter (6 ft.) diameter tunnel installed under complex geology of Staten Island, New York. Contract T-13 is a section of the Oakwood Beach Water Pollution Control Project constructed for New York City Department of Environmental Protection. A knowledge of the subsurface conditions and difficulties experienced on the adjacent contracts called for an innovative approach to handle tunneling under 12 to 17 meters (40-55 ft.) of water in the variable subsurface conditions. This paper describes tunnel design and construction utilizing continuous grouting during advancement of tunnel boring machine and installation of liner plates.

Jan 1, 1993

By J. Y. Hwang, M. L. Jeong, R. C. Greenlund

Various aluminum-smelting by-products from three production sources were received and characterized. The waste materials were tested for compound identification and environmental acceptance. A coarse metallic aluminum recovery test using an Eddy Current separator (ECS) was performed using two different Circuit configurations. White dross performed equally well with either Circuit, while black dross processing shows significant difference on the separation results. It was found that ECS technology was effective for particle sizes down to 6-10 mesh.

Jan 1, 2001

By Liu Cheng-si

The number of control plans for placing control devices in a ventilation network is surprisingly large, but the research result indicates that not all control plans are feasible. The feasibility of a ventilation network control plan depends on two factors. One is the influence of the network structure. The structure must contain one independent variable-flow airway in a non-controlled loop. Otherwise, the control plan is unfeasible. The other is the combination of the air resistance, quantity, pressure and other parameters. Under some conditions, the selected values of these parameters may result in an unfeasible plan. As to the influence of the network structure, when the network structure is simple, the feasibility of a control plan can be judged directly. However, for the influence of the parameters, the feasibility of a control plan must be examined through calculation. The control position has been extended into the natural-splitting subnetwork from the conventional constant-flow subnetwork. This technique is theoretically significant. The extension of control positions results in a great increment in control plans and variation in parameters. At present, the calculation methods of the ventilation network control plans are all available. They are quite useful in selecting desirable plans. However, among the plans found, some are impractical or even unfeasible. If the unfeasible ones can be eliminated at first, much time can be saved in design and calculation. This also facilitates management and decision making.

Jan 1, 1991

By André G. Journel

As opposed to graphics applications in medical sciences and mechanical engineering, computer imaging of the subsurface faces a severe problem of data shortage. Most graphics softwares include an interpolation algorithm aimed at producing slick graphic output, irrespective of the attribute being interpolated, the quantity and quality of the data available, and what the map is intended for. It is suggested that the power of modern computers be also used in providing representations of the subsurface that accurately reflect actual spatial variability and the large variety of soft information available beyond hard data. Since any subsurface representation is uncertain, a measure of that uncertainty should be provided which can be used for risk analysis.

Jan 1, 1992

By Jean-Michel Rendu

Accurate modeling of the semivariogram is an extremely important step in the geostatistical analysis of mineral deposits. Automatic fitting of a mathematical model is often possible but not necessarily desirable. Significant geologic and statistical information must be taken into account in the fitting process, which is not always available to the computer. Manual fitting of the model is, on the other hand, extremely time consuming. Interactive graphics are best suited to optimize the process. A number of interactive methods are described, which are adapted to the modeling of semivariograms in one-, two-, or three-dimensional environments.

Jan 1, 1982

By A. Marabini, J. Cases, M. Barbaro

Outlined is a review of the application of new selective chelating reagents as flotation collectors; calculation methods for the selection of chelating structures, limitation of the function of commercial chelating agents as collectors, and the synthesis of two new classes of chelating collectors with mixed aliphatic-aromatic structure for oxidized lead-zinc ores. Given are: examples of substituted mercaptobenzothiazole and aminothiophenol structures, flotation and adsorption study of an alcoxyl-mercaptobenzothiazole on cerussite, comparison of adsorption of conventional and chelating collectors, study of the influence of the aliphatic structure1 component on the collecting power of chelating type reagent and the design of chelating collectors with optimal structure.

Jan 1, 1989

By J. M. Richardson, A. L. Mular

Metallurgical balances are fundamental to the successful design and operation of concentration and dewatering circuits. With computerized balance techniques gaining prominence in recent years, it is essential that engineers understand the basic principles that underlie the new methods, as well as the various applications for design of new plants and analysis of existing operations. This chapter discusses two important types of metallurgical balance: (1) steady-state design (2) operating data adjustment Application of computerized steady- state design balancing is demonstrated through the example of a typical copper concentrator flowsheet. Operating data adjustment to achieve a consistent balance is demonstrated for a typical concentrator operation.

Jan 1, 1986

By H. Soto, J. Jara, F. Nava, J. B. Hiskey, B. J. Scheiner

Laboratory tests showed that ozone can destroy free cyanide and weakly complexed cyanide (copper and zinc cyanides). The iron cyanide complexes were resilient to ozonation but they were effectively eliminated by precipitation with Fe (II) ions under controlled pH conditions. Tests carried out with effluents from a number of gold mills confirmed the results obtained previously in the laboratory. The industrial samples contained cyanide in the form of free cyanide and also complex copper, zinc and iron cyanides. Solutions that contained up to 184 mg/L total cyanide, after the ozone treatment analyzed only 2-3 mg/L dissociable cyanide and 50-90 mg/L CN(t) (accounted for by iron complexes). After precipitation with ferrous ions total cyanide was reduced below 1.5 mg/L. For most solutions ozone consumption ranges from 3 to 6 g per g of cyanide destroyed. However, certain impurities (such as SCN and S203 ), present in some effluents, increase ozone consumption and make it more difficult to reduce copper concentration to satisfactory levels.

Jan 1, 1993

By M. Y. Fisekci

Subsidence measurement methods, applied over the thick and steep seam mining in the Rocky Mountains Region of Western Canada are described. The studies to date indicate that two new subsidence monitoring techniques appear to be the most suited methods for our conditions. The computerized telemetry and aerial photogrammetry systems are being tested for the reliability of the systems during the winter months within the network of laser surveying over the workings of the new hydraulic mine. The site particulars and the mining method of the concerned area have been described briefly. The observation over the old hydraulic mine indicate that panels adjacent to each other do not obey identical subsidence phenomenon.

Jan 1, 1982