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By L. P. Hendriks

Consolidated Murchison, the only antimony producer in South Africa, is situated in the northeastern part of Transvaal. Phalaborwa, an important copper/phosphate mining town is situated about 60 km to the east of Consolidated Murchison, on the border of the Kruger National Park. The mine is jointly controlled by Johannesburg Consolidated Investment Co. Ltd. (JCI) and Anglovaal Limited.

Jan 1, 1998

By John B. Squyres

The purpose of this paper is to describe certain features of the uranium deposits of the South San Juan Basin, and to suggest a mode of origin for the deposits which is consistent with the data. A series of photographs is included at the end of the paper to illustrate the nature of the ore bodies. Since the general geology of the Grants Region is well described in the literature, it will be only briefly reviewed, and the time will be spent instead on the morphology, spatial relations, and geochemistry of the ore deposits. Part of this material is original, but data and ideas have been taken from a variety of sources, including the literature and the personnel of the USGS, the AEC, and many of the operating companies of the South San Juan Basin. I gratefully acknowledge these sources. The accuracy of the data and the conclusions presented here are my own responsibility, however.

Jan 1, 1974

By James E. Gingrich

The new Track Etch* technique for uranium exploration has been utilized in several survey programs conducted during the last few years. The results from these programs have been very encouraging, and new uranium ore bodies have been discovered by using this new technique. The Track Etch method is being used in several exploration programs in various locations around the world. The Track Etch exploration technique utilizes small pieces of special radiation-sensitive plastic film to detect the presence of radon gas which is released by uranium ore bodies. Because of the selectivity and sensitivity of the technique, ore bodies not normally detected with other surface or airborne monitoring methods are found. Since no large equipment or special training of personnel is needed, the Track Etch technique is easily used in field operations. The basis for the Track Etch method, its application in field exploration programs, and the results obtained to date in locating uranium ore bodies is discussed.

Jan 1, 1974

By A. Ardiant, C. E. F. Mumbunan, I. Irawan

As a part of mine operation’s success key, Community Development nowadays seems to be a rule of thumb. Not only is for a short term need of the company during their operation but also for the national public opinion on the presence of the mining industry to a certain region. Nanggung region which is only a 2-hour drive from Jakarta, brings the challenges to Antam’s gold mine business in the areas such as illegal miner presence, easy access to the mine area as it is very close to the community, and national political sensitivity considering its proximity to Jakarta. The company allocates about 3%of its total operational cost annually for Community Development pro-gram. The program is derived through SWOT analysis and broad involvement of all community components to assure that the allocated fund is addressed to the right place. In the year of 2002, the company has successfully established a conducive-relation with the community.

Jan 1, 2004

By T. Carageorgos

The removal of arsenic from process streams as ferric arsenate compounds is being practised by mining industries. Therefore, the solubility and stability of these solids is of considerable importance to the mining plants that have to keep the environment free from pollutants. There is some information on the solubility of the ferric arsenate compounds, mainly on scorodite, obtained from synthetic solution. However, there is not so much work on ferric arsenate compounds formed at high temperatures (175 - 230°C) during the leaching process. In the present work, the solubility of the ferric arsenate compounds formed during acidic pressure oxidation of arsenopyrite is presented. The results of the solubility tests showed that the ferric arsenate compounds formed at high temperatures (200 - 230°C) and high pressures (1034 - 1551 kPa 0,) released arsenic into solution in amounts less than 1.2 ppm and iron in amounts no higher than 1.0 ppm. So, they seem to be potential compounds for arsenic and iron disposal.

Jan 1, 1998

By Samuel M. Cassidy

The exact date of man's first use of coal is lost in antiquity. The discovery that certain black rock would burn was undoubtedly accidental and probably occurred independently and many times in the world over thousands of years. It is quite likely that these independent discoveries were made when primitive man chanced to build camp fires on exposed ledges of a black rock, then was amazed when it caught fire. The Chinese recorded the use of coal 1100 years before the Christian Era and from the Bible we learn that King Solomon was familiar with coal in what is now Syria. In Wales, there .is evidence that the Bronze Age people used coal for funeral pyres, and it is known that the Romans used this fuel. There are other ancient references. So the knowledge that coal would burn, and even some uses of that knowledge, go back thousands of years. However, practical and consistent use of coal seems to date to England in the Middle Ages.

Jan 1, 1981

By Thomas M. Tharp, Mark A. Travers

A new method is presented for precracking three-point bending specimens for fracture toughness testing. A notched specimen of rectangular cross section is placed on a flat loading platen, with paper between specimen and platen. The specimen is loaded from above through a roller placed directly over the crack. The thin, high compliance joint between specimen and platen causes a distributed load on the bottom of the specimen. This results in bending at the cracked section and crack initiation at the notch tip. Since the joint is thin, its stiffness increases rapidly with deflection and crack propagation in the specimen generally remains stable and controllable. Fracture toughness KIC in a sandstone directly overlying the No. V coal was measured to be 0.27 MPa m 1/2. Even for cracks 1 cm long this value of KIC results in substantially lower effective tensile strength (modulus of rupture) in roof beams than is expected from intact rock strength.

Jan 1, 1986

By Janusz S. Laskowski

The most important type of potash ores, sylvinite, contains sylvite, halite and a small percentage of insoluble gangue [sulfates (anhydrite), carbonates (dolomite), and clay minerals]. Primary normal long-chain amines are exlusively utilized to float sylvite from halite, but since mines are also adsorbed by insoluble slimes, the process requires prior desliming. This is carried out either by mechanical means, or by flotation of slimes and blocking off the adsorption centers on clays with the use of polyelectrolytes. Fractional crystallization is employed to produce fertilizer grade KC1 from disseminated ores with a high content of slimes. An extender oil is needed in addition to mine to float coarse sylvite fractions. The process is carried out in a saturated brine at mine concentrations exceeding the solubility limit and is strongly affected by temperature fluctuations. All these important features, which make this process differ from a conventional flotation, result from a high electrolyte concentration.

Jan 1, 1994

By Fernando de Oliveira Durão

A complete computer package for the steady-state simulation, either in analysis or in design mode, of mineral processing flowsheets is described. The main features of the simulation package are: modular architecture, flexible structure and sequential solution strategy. Different detail levels of mathematical models of several mineral processing unit operations have been developed and implemented as unit modules (FORTRAN routines). Unit operations currently modelled are: coarse/fine crushing, grinding, screening, hydrocyclone classification, gravity separation, heavy media separation, froth flotation, high gradient magnetic separation and solid-liquid separation. In design mode, a simulation study is stated as a general non linear optimization problem. The objective function is a weighted sum of square deviations between the design specification set points and the calculated values, subject to non linear equality and inequality constraints. The optimization problem solution is obtained solving successive Quadratic Programming subproblems followed by inexact line search of an exact penalty function (Powell algorithm). One non trivial example is discussed, illustrating the design capabilities of the simulation package.

Jan 1, 1992

By C. W. Matthews

Introduction Screening is an art, one of the oldest in the process field today, and one of the most widely used in our present age. Screening is being applied to an ever-increasing number of assignments, in an ever-expanding circle of industries. Screening is defined precisely as a mechanical process which accomplishes a separation of particles on the basis of size and their acceptance or rejection by a screening surface. Particles are presented to apertures in a screening surface and rejected if larger than the opening, or accepted and passed through if smaller. Screens are machines with screening surfaces used to classify materials by size. The screening surface is the medium containing the apertures for the passage of the undersize material. Screens are put to many uses - size separation, dewatering, desliming, media recovery, scalping, trash removal, washing, dedusting, conveying, concentration, and many combinations of these functions. It is interesting to note that screens are used for handling commodities

Jan 1, 1985

By Antoni Czubak

It is difficult to simulate properly the vibratory transport. One does not know how to describe the influence of a bulk material layer on the transporting trough. There are few approaches, but none is satisfactory enough. Author proposes to apply a model of a dynamic dumper which simulates periodical collisions between material and the trough, when they are coming to the contact after the free flight of material above the trough. Computer calculates average speed of transported material and handling output as well. When the quantity of material on the trough is known, then the force of the dynamic dumper could be calculated. This force together with the exciting force of the vibrator are introduced into equations describing the model of a mutti- mass conveyor. The basic goal of simulation is to find the required exciting force and the power of an electromagnetic vibrator. it is possible to find optimal data of designed elements of vibratory conveyors as well.

Jan 1, 1996

By Fred C. Wrobbel

Two counties in Illinois, Ope and Hardin, and three counties in Kentucky, Crittenden, Livingston and Caldwell comprise the entire Kentucky-Illinois fluorspar district. The output from these five counties, however, makes up over 60 percent of our domestic fluorspar production, amounting to some 175,000 tons of finished product in 1956, The area is rough and hilly. It is bisected by the Ohio River, and has numerous smaller rivers and creeks. Add to this a generous average annual rainfall, in excess of forty inches, and it is understandable that the-area-can boast of an ample water supply. An abundance of water, however, is unfortunately not always conducive to ideal mining conditions. The faulted structure of the area and the soluble Mississippian limestones make the subsurface sediments' willing hosts to the surface water. Limestone cavers and sinkhole topography also compound the occurrence of underground water. It is little wonder, then, that water frequently presents an economic problem in the area, particularly in vein-type mining.

Jan 1, 1958

By P. Venkatasubramanian

The selection of a mining method for a mineral deposit is a complex decision problem. Human judgment, based on experience with mineral deposits and geologic conditions, remains the single most important input of the decision-making technique. If the use of artificial intelligence, in particular the developments in expert systems, is taken to its logical conclusion, the experience of the domain experts could be incorporated into a decision-support expert system. A knowledge-based decision support system for mining method selection for ore deposits has been designed whereby the domain knowledge is represented as production rules and organized in a semantic tree representation. This model is written in the PROLOG language. While the verification difficulties of expert systems models are recognized, an example of the model's decision on the mining method for a given ore body is presented and shown to be consistent with the decision made by human experts. In addition, plans, for further verification of the model are delineated.

Jan 1, 1992

By Nicolae Dobritoiu

From experience and scientific references it is known that during information processing, the following error types are transmitted: technical, analogy errors and method errors. For decreasing the value of these errors, especially of the method ones, old algorithms should be perfected and new ones should be developed for processing, interpreting and achieving the graphical layout by means of automatic data processing. In this respect, we propose a new deposit model based on numeric mathematical modelling which requires the use of automatic data processing. The utilization of the numeric model of the proposed deposit, allows the obtaining of the following advantages: • the model is used for any deposit form; • it is used for the calculation of deposit resources (volume, weight, and content); • it is used in design due to the facility of obtaining sections through the deposits area; • it eliminates at "0" the errors of graphical data transcription; • the use of the model imposes a uniform geological research; • the algorithm is transposed in a package of programs.

Jan 1, 2002

By H. Sevim

A new method of designing haulage systems, consisting of belt conveyors and hoists for underground mines is discussed in this paper. Efficient and economic design of such systems will prevent operational bottlenecks and provide savings. The developed model uses a heuristic algorithm to optimize the design parameters and to select the proper equipment specifications. It is a probabilistic model because it considers the probabilistic aspects of face operations. It is versatile because it can accommodate belt conveyor networks of any configuration and hoisting systems that can be either drum or friction hoists for single or multiple-level operations. The model also has the option to internally determine the required capacities of the bunker(s) and shaft- bottom bin. The objective of the optimization process is to minimize the "expected cost per ton of ore hauled" from the working faces to the surface. A numerical example is included to illustrate the capabilities of the model.

Jan 1, 1987

By L. S. Gourevitch, E. B. Kremer, A. Y. Fidlin, Y. M. Katsman, I. I. Blekhman

A new kinetic approach to simulation of fracture is given. The main object of the simulation is forecasting transformation of ore lumps size distribution in squeezing of ore layer between two planes. The approach rests on fundamental principles of energy and mass conservation and on new ideas about fracture physics connected with fractal geometry. On this base an integro-differen tial equation of layer crushing kinetics is formulated. This equation is similar to well-known kinetic equation of grinding, but here we use elastic energy density in place of time as an independent variable while selection function is considered by us to be dependent on this variable. Properties of the equation have been investigated by us and its analytical solution has been found. It allows to compute simultaneously both the evolution of the size distribution process of squeezing and force-displacement diagram. Results of theoretical calculations provide a good fit with experimental data.

Jan 1, 1995

By L. Henry Smith, David C. Arthur

The Williams Mine is Canada's largest gold producer, with annual production of 14,000 Kg (450,000 ounces) from 2,300,000 tonnes of ore. Highly mechanized and automated underground mining practices are employed in order to achieve and maintain high levels of productivity and minimize costs. The Mine Ventilation System is modified to include a new Vent Raise and Variable Pitch Vane-Axial Fan. This addition allows several fan installations underground to be decommissioned. A substantial net savings in installed horse power is achieved. Heating costs associated with underground ventilation air are a significant portion of mine operating costs. Air heating costs are substantially reduced by recovering heat from upcast exhaust air, mine water and compressor cooling circuits. This waste heat is used to supplement propane fired air heating systems for underground ventilation air. An additional benefit is the availability of a heat sink for summer cooling of the compressors. System design, energy savings data and payback calculations are presented.

Jan 1, 1997

As discussed previously, total cost is the sum of the direct materials, direct labor, and production overhead costs. The assignment of direct materials and direct labor costs to individual activities is generally straightforward. The assignment of overhead often is not. Overhead costs frequently contain allocations that only approximate the demand the activity has made o; the overhead resources. The inaccuracy of the overhead calculation can create erroneous production cost information and lead to suboptimal management of the operation. This problem is particularly acute when determining the production cost of individual products in multiproduct firms. Pricing, process management, and product mix decisions are especially susceptible to errors in product costing. The problem of properly determining production cost is complicated by the fact that few if any alternative methods exist to identify the inaccuracies in overhead allocation. To avoid errors, some firms simply ignore overhead costs in their product cost calculations, particularly those resulting from marketing and distribution of the final product.

Jan 1, 1999

By B. J. Arnold, C. D. Harrison, R. A. Lohnes

More than 544 Mt (600 million st) of coal are handled annually for use by this country's coal fired power plants. Coal is transported in various ways: overland conveyors, railcars, trucks and barges. It can travel short distances or thousands of miles, picking up moisture, freezing or drying. When the coal is received at the power plant, environmental problems with fugitive dust and further handling problems can arise. To ensure that power plant availability is not jeopardized by coal handling problems, the Electric Power Research Institute's (EPRI) Coal Quality Development Center (CQDC) developed a research program aimed at addressing utility coal handling problems. The program has identified key areas, and is investigating the cost and cause of coal handling problems as well as the solutions to these problems. The ultimate goal of the program is to develop a "handleability index" that utilities can use in their coal specifications or hardware for a utility's sampling system to predict handleability and determine if a coal shipment should be accepted.

Jan 1, 1993

By Yehia M. Eyssa

A "straight wire" flow through magnetic ore separator has been designed, built and successfully used to separate magnetite from typical slurries. The purpose of these experiments was to simulate the high field profile of a "straight wire" superconducting magnetic separator which would be capable of separating weakly magnetic hematite ore from typical slurries. Magnetite was used as the test mineral because it experinces the same magnetic forces at low field as does hematite at high field. The present separator concept is based on the fact that there is a particle concentration profile due to the gravity field for low velocity turbulent flow. When a magnetic field force of -g is applied the concentration profile of the magnetic particles will be reversed leaving the nonmagnetic particles flowing alone at the bottom of the channel. By means of a divider at the end of the channel the concentrate is separated from the tailings. It is shown that the time needed to deflect hematite particles in a narrow cylindrical channel concentric with the superconducting wire is small enough so that high throughputs in the turbulent flow region are possible. In the case of a high field superconducting separator the centrifugal force could replace gravity by rotating the flow around the straight wire conductor.

Jan 1, 1974