Search Documents

By G. J. Lindenburg, T. L. Wilson

The Velvet uranium mine is located in the Big Indian district of the Colorado Plateau. The uranium ore body lies within the lower Triassic Chinle Formation, and the ore is associated with west-south- westerly trending fluvial sand systems. Exploration and mining are directed by longhole drilling and radiometric sampling. Results of the gamma probing, face scanning, and geologic mapping guide mining decisions and planning. Three people are directly involved with the geologic procedures: two geologists and a mine supervisor. The two geologists map, do rib scans, and direct longhole drilling. The third man involved, the mine supervisor, has last minute directive action based on shot hole probe data.

Jan 1, 1984

By G. Rinelli, A. M. Marabini

Flotation of rutile with N-benzoyl-N-phenyl-hydroxyhmine (N-BPHA) has been investkated. Initially, floatability tests were performed in a Hallimond tube. The results indicated that rutile was floatable at pH 2-4 with N-BPHA concentration between 2 x 10-3 mol/L and 2 x 10-2 mol/L. Selectivity against hematite was recognized when operating at pH values below 2. Following the hypothesis of the formation of a surface chelate between N-BPHA and titanium ion, this compound was precipitated from a solution of Ti (SO4)2 to which N-BPHA was added. I. R. spectrometry of the rutile before and after treatment with N-BPHA solution confirmed the presence of this compound on the rutile surface. Adsorption isotherm and kinetics were determined by analyzing N-BPHA in solution with an U. V. technique. A hypothesis on the way N-BPHA is adsorbed on rutile is presented.

Jan 1, 1984

By Eupene GS

The Early Proterozioc Pine Creek Geosyncline hosts a large number of gold showings. Mineralisation types include stratiform, synsedimentary deposits within iron formation and carbonaceous mudstone; disseminations in granophyric intrusives; and quartz vein related concentrations in the form of shear fillings, saddle reefs and stockworks. Stratiform gold deposits preferentially formed near penecontemporareous faults during periods of basin instability. Intrusive basic magmas later assimilated some stratiform mineralisation and subsequently redeposited it within differentiated phases. Gold was again remobilized during regional deformation and metamorphism. Stratiform mineralisation was upgraded insitu in high strain zones and gold was mobilized into metamorphic fluids. Fluid induced fracturing during prograde metamorphism and later uplift caused the deposition of extensive gold rich vein systems. The genetic relationship between gold deposit types is reflected in the clustering of showings along regional anticlines, and provides a powerful exploration tool. The large volume of 'exhalative'òmaterial in the Geosyncline with elevated gold content suggests significant economic stratiform mineralisation may be present, and probably provides a source for later disseminated and vein deposits.

Jan 1, 1984

By Shuichiro Okada

The Tamano Smelter, which is engaged in copper smelting by Flash Smelting Furnace with Furnace Electrodes (FSFE) has since 1982 revised its computer and associated control system for the purpose of greater energy savings, stable operation, and strict environmental control. This revision is bringing about a remarkable cost savings through greater reduction in energy consumption. This paper describes in detail the following: (a) outline of renewed process computer system, (b) approach to prediction model of FSFE based on data collection and its analysis, (c) actual examples of process control by using its prediction model, (d) future trends in the computer control at Tamano Smelter.

Jan 1, 1984

By P. L. Lavery

A numerical method to derive approximate solutions for stress intensity factors for rectilinearly anisotropic bodies without resolving to complex variable approach is presented. The method is based on the assumption that the crack opening profile can be simulated by a simple curve such as an elliptic function and a relationship is found for the stress intensity factor in terms of near tip displacements. An example solution is derived for a transversely isotropic body and the results are verified with Westergaard's stress function approach. The proposed model has a great potential for the applications to fracture mechanics of anisotropic rock materials.

Jan 1, 1984

By J. E. Schiller, S. E. Khalafalla

Due to its unique surface properties, magnesium oxide (MgO) is an excellent medium to filter asbestos and other suspended solids from water. MgO operates up to twice as long as a sand filter before backwashing is required while flow rate and filtrate clarity are as good or better with MgO.

Jan 1, 1984

By Kenneth A. Pietila

The thickening and dewatering characteristics of refuse slurries are as variable as the coal mining operations and preparation plants that create them. This paper discusses these characteristics based on field studies at a number of mine sites. The connection between bench and full scale performance is confirmed with the design, construction and operation of an integrated 18m (60 ft) diameter thickener and 2.5 meter belt filter press system in Western Kentucky. The data from this system are presented.

Jan 1, 1984

By Gennaro G. Marino

This paper summarizes and evaluates data on mine subsidence ground movements and associated damage for houses in Illinois. Based on the data collected, the response of homes to subsidence ground movements is expressed in terms of repair costs. A damage criteria is then proposed that relates the ground movements and damage levels. The data were collected as part of a comprehen¬sive study performed for the Illinois Abandoned ?Lined Lands Reclamation Council, A -M-RC, by the Civil Engineering Department at the University of Illinois, and probably will be published in late 1934 by the council. The study concentrated its efforts on surface ground movements and the effects to houses over abandoned room and pillar mines. The resultant surface subsidences are commonly dish or bowl shaped and are termed sags. Method of Analysis The steps in analysis used to arrive at the proposed damage criteria are: 1. Canvas and rap subsidence damage in houses, 2. Assess the associated ground movements, 3. Estimate the damage repair cost, 4. Develop a damage/repair level classifica¬tion, 5. Correlate the associated ground movement, damage/repair level and home construction type, 6. Propose a damage criteria.

Jan 1, 1984

By D. A. Buckingham

The Bureau of Mines evaluated potential availability of domestic nickel from 23 deposits, Evaluations included an estimation of in situ and recoverable resources, applicable mining and processing technologies, and capital and operating costs. Discounted cash flow analysis with a 15-pct rate of return was used to determine the average total cost of production of each operation, Identified in situ resources contain 9.0 million metric tons (t) of nickel; 5.5 million t is recoverable as nickel metal or ferronickel. Demonstrated in situ resources contain 8.2 million t of nickel; 4.8 million t is recoverable as nickel metal or ferronickel. No nickel is available at a total cost of production equal to the January 1983 market price of $3.24 per pound. Analyses indicate that potential annual production can only meet current consumption levels at a total cost of production of $7.60 per pound of nickel, Nickel's availability is contingent on (1) successful adaptability of nickel processing methods to domestic resources, (2) location of a smelting facility, and (3) marketability of byproducts and coproducts. Analyses were performed on the effects of byproduct and coproduct revenues, energy, labor, and transportation costs, and metallurgical recoveries on nickel's availability.

Jan 1, 1984

Develop methods to detect and repair poorly functioning dust collectors on roof bolters. Approach In conjunction with a research project to reduce silica dust in coal mines, a variety of roof bolting machines operating under different conditions were examined to find out how much these machines were contributing to the silica dust problem. Results The investigation concluded that if the bolting machines' dust collector is properly maintained, very little dust can be measured in the air, even with minimal airflow over the bolter. Poor maintenance, however, frequently results in high dust levels. Three major problem areas were found. These were: (1) filter leaks, which allowed dust to escape, (2) accumulations of dust in the collection system, and (3) low airflow at the bit due to hose, fitting, and relief valve leaks.

Jan 1, 1984

Design, fabricate, and test a machine capable of operating in coal seams 48-inches and thicker that can reduce the time, expense, and injury potential inherent in extending and retracting mine-wide section belt conveyors, while eliminating the need to use additional machinery or equipment in accomplishing such moves. The Problem Many underground coal mines use a belt haulage system to move cut coal from the face to the loading area. This system usually consists of a main line belt conveyor fed by section belt conveyors. A shuttle car at the face carries the coal cut by a continuous mining machine to a feeder breaker that breaks the large lumps of coal into smaller, transport-able pieces and unloads them onto the tail piece of the section conveyor. This tail piece is skid-mounted so it can be readily moved as needed. The conveyor is kept close to the face during mining in order to shorten the haul distance of the shuttle cars. Section belts can be lengthened by adding belting, wire rope, and support hard-ware. During pillar retreat mining, these section belts are shortened to keep pace with pillar extraction operations. However, these belt moves, either the extensions or retractions, usually require six to eight workers and three to eight hours to complete. In addition, a 100-foot belt move requires workers to handle up to 4,000 lbs. of material, not including the tail section. Strain and sprain injuries can be incurred during this heavily labor-intensive task. The time required to move the section belt can also create losses in the mine's production. To help solve this problem, the Bureau of Mines

Jan 1, 1984

By W. E. Coughlin, R. L. Faverty, F. H. Lightner

The intent of this paper is to present the general strategy and method of implementation to achieve a "fast-track" mine development. The major objectives of a "fast-track or rapid development schedule are to minimize front-end development expenditures and to realize an early cash flow from operations. The Borealis project of Houston International Minerals Corp. (HIMCO) is used as the working example to illustrate the development schedule. Borealis is a 2.9 kt/d (2,500 stpd) gold-silver heap leach operation near Hawthorne, NV.

Jan 1, 1984

By Robert J. Brison

On the basis of experience accumulated during the completion of some 150 gold/silver process development projects, general guidelines are presented for developing the most cost effective process for a specific project. Steps involved in process development for lode ore deposits generally include a review of pertinent background information on the ore deposit, sample procurement and preparation, sample characterization, study of concentration possibilities, investigation of leaching and metal recovery methods, economic evaluation of alternative processes, optimization of the selected process, a pilot plant program if warranted, and finally, process design and feasibility studies. Each of these steps is discussed, with emphasis on the relation between technology and economics.

Jan 1, 1984

By Wilson AF

Gold-silver mineralization at Cracow and Ukalunda in Queensland comprise quartz-filled veins, fissures and breccia zones hosted by propylitically altered volcanics and epizonal intrusions which are strongly fractured. The terrestrial volcanic facies, structural setting, type of alteration and complex mineralogy suggest these deposits are of the epithermal type.The 180 depleted character of the wall-rocks is consistent with the involvement of meteoric waters in convective hydrothermal cells associated with the vulcanism. The Cracow quartzes have remarkably low 6180 values from -2.0 to -3.4 per mil typical. of meteoric hydrothermal systems at high latitude, consistent with the inferred position of Australia during the Permian. 6180 values for the Ukalunda quartzes exhibit a wide range from 5.1 to 14.9 per mil which reflect the mixing of magmatic and meteoric waters, and a steep geothermal gradient.Further stable isotope and geochemical studies are in progress to establish the scale and morphology of the zones of anomalous 6180 and mineralogy in the wallrocks which constitute significant exploration targets.

Jan 1, 1984

By W. Kane, M. Karmis

Roof and rib failures in underground coal mines are one of the major problems facing the industry today. In addition to safety considerations, the resulting economic impact of such failures is staggering. Uncovering and replacing buried and damaged equipment and clearing entries can account for a large expenditure in lost man-hours and machinery. Yet, because of the complex nature of its formation, geological variability, and structural characteristics, coal mine roof strata is one of the least controlable of all mine design parameters. This is especially true along the leading (southeastern) edge of the Appalachian coalfields where considerable faulting and movement has contributed to hazardous coal mining roof conditions. During this research, a detailed study of several mines, in the southern Appalachian coalfields, was undertaken to determine the most prominent geomechanical factors affecting roof stability and to evaluate their influence in promoting unstable ground conditions. In order to accomplish this task, the major geological and geomechanical features found to be detrimental to coal mine roof within the Appalachian basin were identified and mapped in four Virginia mines. Statistical processing by chi-square and regression analysis was used to determine the influence of geology, mine-layout, and support methods on roof stability. It was found that some easily determined parameters can be successfully used to predict potentially unstable areas. A simplified roof classification system was developed based on these geomechanical parameters, which can be used to assess the stability of a particular roof type. A roof rating index was also devised capable' of expressing the probability of a failure under a given set geomechanical condition.

Jan 1, 1984

By Childs G, Ritchie IC

This paper describes the principle and operation of small hydrocyclones for use in the coal, minerals and other process industries. The principles for selecting a hydrocyclone for an application are also discussed. Typic- al uses and installations in various industries are described.

Jan 1, 1984

By K. V. S. Sastry

First attempts to apply computers for the modeling, simulation and analysis of mineral processing unit operations date back to almost twenty years. Since then substantial efforts have been directed to the development of computer software for mineral processing. Current literature indicates considerable activities in the development of computer packages for interactive and batch simulation of individual unit operations and integrated plant operations. This paper presents a comprehensive review of various simulation systems that have been described in the literature along with a discussion of present trends in the development of mineral processing simulation software. Finally, the paper includes a detailed discussion of the desirable features in future simulation packages.

Jan 1, 1984

By Robert C. Gabler

Three filter cloth fabrics commonly used in drains for coal waste embankments were tested by the Bureau of Mines for clogging behavior and deterioration under simulated field conditions. The objective was to provide guidelines for the mining industry for the proper selection and use of filter cloths to assure safer embankments at mine waste disposal sites. The filter cloths were tested with three coal waste samples in stand-pipes used to simulate coal mine waste disposal environments. Two of the cloths showed a tendency to become clogged with fines from the wastes. One waste caused clogging by precipitating an iron-silicon compound on the test cloths. No apparent cloth deterioration resulted from exposures to the simulated coal waste environments. (The exposures ranged from 2 to 12 months.) In other tests, exposures to waters in the pH range of 2 to 12 and to reagents used in coal-preparation plants resulted in insignificant or no deterioration, as measured by tensile strength. However, long exposures to sunlight (ranging from 4.6 to 6 months) caused major deterioration in two of the cloths (86-and 98-pct losses in tensile strength) and slight deterioration in the third cloth (9-pct loss in strength).

Jan 1, 1984

By Michael J. Fiannaca

Disseminated epithermal gold metallization occurs within a breccia unit interpreted to be a submarine debris flow. Cold is associated with oxidized pyrite, fluorite, and jasperoidal silica. A minimum of 9 million tons of open-pittable mining reserves will be cyanide heap leached as run-of-mine ore at a rate of 1.0 million tons per year. Careful evaluation of the combined results of successive sampling projects has established the pit plan, mineable reserves, and process metallurgy of the operation. The sampling procedure utilized for a given test depended upon geological interpretation as well as the procedures, successes, and failures of previous tests. This paper summarizes the sampling and testing procedures of the development effort in light of the project goals and attendant problems in achieving them.

Jan 1, 1984

By J. R. Hillebrand

From the abstract, "A realistic ore deposition model to serve as a conceptual framework." Further, on page 246, "The first area of study was the Josephine peridotite, now identified as an ophiolite terrane, located in northern California and southwestern Oregon (Fig. 3). Here, it was felt that we could test the models shown in Figs. 1 and 2 and, if successful, expand the model and test it in other chromite districts in the US and around the world." My comments refer only to chromite deposits in Europe and the Middle East. First, I question that may chromite deposits occur in the idealized ophiolite section shown in [Fig. 1]. Second, although some podiform deposits (referring to morphology) have been important (Gulernan, Turkey, for example), the stratiform deposits are of greater importance in tonnage and frequently grade. Examples include Nada, Yugoslavia; Bulqiza, Albania; Xerolivado, Greece; Saranovsk, Russia; and Abdasht, Iran.

Jan 1, 1984