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By Hassan El-Shall, Abbas A. Zaman, Brij M. Moudgil

The addition of organic and inorganic dispersants to aqueous suspensions of heterogeneous particles (kaolin) was found to significantly affect the solubility of metal ions from kaolin particles and stability of the dispersion. In most of the industrial applications of kaolin, highly concentrated slurries of controlled stability and fluidity are required. The solubility of kaolin particles in terms of aluminum and silicon ions and its effect on the stability of the slurry was investigated. The main objectives of this study were (1) to study the effect of the extracted metals on the properties and performance of the slurry, (2) to understand the reaction mechanism of dissolution of metals from kaolin, and (3) to understand the interaction mechanism of dispersants with kaolin particles. The controlling variables were dispersant dosage, slurry pH, solids loading, and aging.

Jan 1, 2003

By R. G. L. McCready, G. Dr. Heinrich, V. I. Lakshmanan

The objective of this study was to prove repeat loading capacities of physically stabilized fungal biomass from Penicillium sp. for the removal and recovery of uranium from mine water (Denison Mines). The testwork was carried out on a bench scale in small columns and proved that it is possible to stabilize the biomass in an inorganic compound. A lifetime of 10 loading-eluting cycles of the stabilizer biomass product was obtained by additional pretreatment. Sodium carbonate proved to be an effective elution medium. Loading and elution can be controlled by the pH values of the column. The effective loading capacity until the breakthrough point is approximately 70 % of the overall loading capacity. The loading capacities of the stabilizer biomass product are comparable to that of the original biomass. Uranium recoveries of 90 to 99 % were achieved during the loading and eluting under optimized conditions. Depending on the used biomass the described process might be applicable to remove uranium or other dissolved heavy or rare metals from effluents.

Jan 1, 1989

By Ray Soper

Important progress has been made in developing the K-Process as an alternative to cyanide as a method of recovering gold from ores and other materials.

Jan 1, 1998

By Richard Newcomb, Michael Rieber, William A. Vogely

INTRODUCTION The solid fossil and nuclear fuels, but especially uranium, are given prominent, indeed leading, roles by energy experts in most long range estimates of world energy futures. Optimistic forecasts are inspired partly by the disproportionately large solid fuels resource base compared to present rates of consumption or to oil and gas resources, and partly by the vision of inexpensive high technology applications. Such a view overlooks the fact that while resource- use disparities and new technologies give allure to the promise of the solid fuels, they do not guarantee cheap solutions to the basic problems of solid fuel uses: viz., their relatively difficult conditions for efficient ignition and control, including the management of environmentally acceptable residuals disposal. Contrary to the varied versions of this optimistic hypothesis, this paper shows that a great many persistent economic and technical problems interfere with such a simple inference. These act as constraints which qualify or dispute much of the national energy policy based on existing modeling of solid fuel requirements and optimistic engineering evaluations. The assumptions and techniques of such exercises are sometimes at fault. As often as not, however, the distortions created in open market fuel com- petition due to misdirected national energy policies themselves are to blame for misdirected efforts. A number of interesting implications result. Among them are the distinct possibility that the low technology applications will dominate, so that more direct coal and less synfuel or nuclear use will occur; that, accordingly, exhaustion rates for uranium will be low, that the most extensive growth of solid fuel through 2000 will be in conventional pulverized coal cumbustors, and that the traded share of the world coal bum will be much larger than predicted. These trends will place much more pressure on oil and gas prices than forecast by most experts. On the way to these findings the paper demonstrates that solid fuel resource adequacy in situ, balanced against the projections of demands as capacity requirements, mean little as conventionally measured by years to exhaustion or potential supply schedules. Indeed, all stock concepts of demand requirements or of fuel re- sources must be tied to the paths of the unit costs and the deliverable prices of all substitute fuels and systems over time. This requires a dynamic analysis of supply and demand, integrated with geological and engineering constraints, to provide insights into the multiple modes of market and product substitution. Market forces rather than technical promise will determine the allocation of the solid fuels. Moreover, the equilibrium paths of individual fuel prices and market shares are not easily simulated by general or network models, and decision makers will continue to rely on the partial, local comparison of alternatives in their choices of fuel systems at any time. 'The economics of the solid fuels differs from that of other energy sources in important ways relating to their form in use, conversion efficiency, (dis)economies and externalities. Petroleum and gas are in a more convenient form for

Jan 1, 1985

By Danqing Gao, Brijes Mishra

Heterogeneity in rock formation affects both rock behavior and strength. Spatial variance of rock properties is an important characteristic of rock that addresses the heterogeneity of mechanical and physical properties and their effects on underground mining. Assessing spatial variance can be useful for locating potential difficult grounds and for performing reliability analysis in the mining support system. This study presents a spatially correlated, random model to investigate the influence of rock heterogeneity on rock strength and failure propagation. A random field database with specific spatial correlation was created for each physical-mechanical property using laboratory data and the extreme value stochastic model in MATLAB. Based on the improved microscale random model, we considered one three-dimensional numerical model to study a mine operating in the Pittsburgh seam. The influence of random field data on entry roof was investigated. The realistic random field database added two scale-measured parameters from horizontal and vertical directions to control the spatial correlation length. A number of cutting sequences were also considered in order to identify the effect of spatial variance on roof behavior. The results show that spatial variance provides an accurate prediction of erratic roof falls in coal mines.

By Paul Chamberlin

Although performing a heap leach test is inherently simple, a lot of information beyond extraction, leach time, and reagent consumption can be obtained from a well designed test program. The following is a list of information to look for and acquire when performing column tests and field heap leach tests.

Jan 1, 1998

By I. Yaniv

The magneto-hydrostatic method can be used today to separate slightly magnetic or non-magnetic particles according to differences in their specific gravities and magnetic susceptibilities. The classical approach is to effect stratification prior to separation. This paper discusses some of the significant parameters which bear on the design and pattern of the expected stratification in the separation cell. As the characteristics of the magnetic field, and consequently those of the magnetic forces, are determined by the geometry of the poles, this subject is treated first. In this context a new approach, whereby the range of stratification is extended, using positive as well as negative gradients, is presented. Finally, the effect of the relative size and shape of the particles on stratification is discussed.

Jan 1, 1978

By Werner Burger, Marcus Lübbers

TBM development in recent decades has been dominated by increased face pressures, larger diameters and multi-mode functionality paving the way to realize projects deemed impossible before. In addition, the trend towards digitalization does not stop at the tunnel portal. A shortage of skilled personnel and the ever-present wish to increase workplace safety, quality and system performance automation, operatorassist or even autonomous systems have become key development targets. The paper will present the current state of the art in light of these special conditions.

Jun 13, 2023

By R. A. Metz, Michael M. Easdon, Michael J. Fiannaca

Disseminated epithermal gold metallization occurs within a breccia unit interpreted to be a submarine debris flow. Gold is associated with oxidized pyrite, fluorite, and jasperoidal silica. A minimum of 8 Mt (9 million at) of open-pittable mining reserves will be cyanide heap leached as run-of-mine ore at a rate of 0.9 Mt (1.0 million stpy). Careful evaluation of the combined results of successive sampling projects has established the pit plan, minable 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, 1992

By A. M. Stone

Following the conceptual idea of a Continuous Elution Process early in 1982, the system was successfully pilot plant tested at Western Mining's Kambalda gold plant in December 1982. As a consequence of these tests the Ok Tedi elution ciruit design was changed from batch operation to continuous operation resulting in a reduction in the number of similarly sized elution columns from five operating with one standby to one operating with one standby and halving the process steam requirements. In addition to providing significant capital and operating cost savings the continuous process was simpler to operate than the batch process.

Jan 1, 1989

By R. O. Burt

The Tanco pegmatite is located in the Bird River greenstone belt of south-eastern Manitoba approximately 160 km northeast of Winnipeg (Figure 1). The orebody was discovered in 1929 and subsequently attempts were made to exploit it for tin by Jack Nutt Mines Ltd. and later in the middle 1950's by Montgary Oil Ltd., who extensively developed but did not produce from its lithium deposits. In 1966 systematic investigation of the pegmatite as a potential source of tantalum led to the founding of Tantalum Mining Corporation of Canada Ltd. (TANCO), and production of tantalum concentrates from the Bernie Lake mine commenced in 1969. Tanco's currently jointly owned by Hudson Bay Mining and Smelting Co., Cabot Corporation, and the Province of Manitoba.

Jan 1, 1988

By R. R. Klimpel

The use of froth flotation as a means of separating and upgrading sulfide mineral concentrates is standard industrial practice throughout the world. It is ap-parent from observing the industrial practice of sulfide mineral flotation over the last decade that progress is being made in optimizing the operating aspects of flotation. Examples of this are the availability of improved instrumentation and related computer control devices, the modification of mechanical flotation cell designs, the introduction of column cells, better reagent dosage control, blending of feed ores, increasing attention to coarse and fine particle separations, the successful introduction of new frother chemistries, etc.

Jan 1, 1989

By Charles C. Mosher

An in-mine seismic technique for detecting faults has been tested in a Western U.S. coal mine. This technique has been used extensively in the U. K. to help guide longwall mining operations. Explosives detonated on the face of a seam generate sound waves which propagate into the seam. Reflections from faults are picked up by sensors on the same face. Computer processing is then used to determine the fault locations. A known fault was successfully located in this test. Modifications to the U. K. procedures were required for the relatively thicker roan and pillar mines common in the Western U. S.

Jan 1, 1983

By S. F. Walsh

The San Manuel Oxide Pit is located within the subsidence boundaries of Magma Copper Company's block caving operation. Ground conditions offer a constant blasting challenge and vary from hard, competent crystalline rock to widely spaced fracturing in a sedimentary conglomerate. A successful drilling and blasting program has undergone several changes since mining commenced in 1985 and continues to be developed. This paper discusses the site specific progress made with the drilling and blasting program from selection of feasibility parameters to current practice. Topics discussed include controlled blasting, use Of high energy blasting agents, charge decking, blast casting, as well as standard drill and blast techniques.

Jan 1, 1988

By M. V. Chari

A prime objective of physical coal cleaning is the separation of raw coal into a clean coal product with the required low ash and pyritic sulfur content and a high ash refuse. The refuse should also contain a minimum amount of combustible matter. In order to be effective, cleaning processes require that the mineral matter in the feed, including pyrite, be largely discrete and free particles, liberated so that the particles are not attached or embedded in coal. Liberation of mineral matter from coal, particularly pyrite, was investigated by Bechtel as part of two fine coal cleaning research programs sponsored by the Department Of Energy (DOE), Pittsburgh Energy Technology Center (PETC). Two proof-of-concept (POC) plants, each with a capacity of 900 kg per hour, were installed and tested to evaluate production of ultra-clean coal using microbubble flotation and spherical agglomeration technologies. The plants were designed to produce clean coal with 2 percent ash and pyrite content lower than that achievable by conventional methods. Also, the quality targets were to be attained at energy recoveries above 80 percent. Bench-scale flotation and agglomeration tests indicated that it would be practical to grind the 6 mm top size feed coal to a mean particle size (050) of 10 micrometers in the POC test plant. In this part of the paper, the steps taken in the grinding circuit to maximize liberation of mineral matter are described.

Jan 1, 1991

By R. K. Mehta

A review of the literature reveals that methods for simulating the coupled behavior of size reduction and liberation are limited to binary mineral systems containing one composite particle class. The aim of this paper is to describe the development of a mathematical model to simulate such behavior for binary and ternary systems containing multiple classes of composite particles. A modified Levenberg-Marquardt algorithm and a finite difference Jacobian are used in conjunction with the developed model and a set of constrained equations to estimate all kinetic parameters. This estimation scheme is validated for a binary ore (sphalerite-dolomite) with five composite particle classes using experimental data.

Jan 1, 1989

By Jorgensen D. K.

The Bullfrog and Montgomery-Shoshone deposits, outside Beatty, Nevada, have a combined drill-indicated reserve of 17.4 M tons of ore with an average grade of 0.103 oz/t Au and 0.240 oz/t Ag. The deposits occur in Miocene volcanic rocks which underwent large-scale movement within a detachment-faulted terrane. The principal host to gold mineralization is a strongly welded rhyolitic tuff which experienced brittle deformation during plate movement. Open-space fractures and breccia were filled with quartz, calcite, and adularia accompanied by lesser pyrite, gold, and acanthite. Gold occurs as micron-sized particles within and adjacent to the low-angle fault and along associated listric-normal and tear faults.

Jan 1, 1989

By J. L. Fuller

This paper contains a brief summary of design descriptions and generally accepted designations for longwall ventilation systems. Various ventilation systems for longwalls developed using single-entry and multiple-entry systems are discussed. Design considerations specific to longwall mining are included.

Jan 1, 1989

By Newell H. Orr

Titanium's performance characteristics in acidic oxidizing and mildly reducing environments make it applicable to numerous currently defined and many projected hydrometallurgical applications. With titanium's current and projected availability and price stability increased use in pressure leach, piping systems and electrorefining is practical.

Jan 1, 1983

By A. G. Mayton

Bureau of Mines research has addressed improved operator protection for thin-seam shuttle cars. Because of working height restrictions in thin-seam mines (1.22 m or 48 in), MSHA regulations require that-canopy protection on shuttle cars be provided only in mines 1.07 m (42 in) and greater; however, variances are given to mines 1.22 m (48 in) and below. This paper reviews past Bureau efforts to develop protective structures for thin-seam shuttle car operators. The paper also discusses recent research leading to a novel method of protecting shuttle car operators, in mines as low as 1.02 m (40 in), through the use of a cross-car, end-mounted operator compartment.

Jan 1, 1989