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By Thomas E. Shufflebarger

Glass sand is a virtually pure, fine- to medium-grained, quartz sand. It is produced in 25 states from a variety of chemically different source rocks. Deriving their raw material largely from either friable sandstones or loosely consolidated sands, 59 operations produced 14.9 million tons of melting sand in 1976. About one-third of this tonnage was obtained from the Oriskany and St. Peter Sandstones. Glass-sand prospects are discussed in this paper with regard to chemistry, environment, transportation, and costs. Demand for a quality product will range from 36 million to 46 million short tons in 1995.

Jan 1, 1978

By Qun Wang, Elena A. Alonso, Janusz S. Laskowski

Primary normal long-chain amines are insoluble in saturated brine. Their colloidal solubility (dispersion) in concentrated electrolyte solutions is strongly affected by the presence of surfactants (frothers). This paper shows that a better usage of alcohol type surfactants, which are commonly used in potash ore flotation as frothers, can significantly improve the flotation of both coarse and fine sylvite particles. A new process of potash ore flotation is developed, which includes premixing an effective frother with an aqueous solution of amine or emulsion of extender oil containing amine. With such a combination of flotation reagents, KC1 particles up to 5 mm in size float very well in the short flotation column, and particles up to 2 mm float in a mechanical cell; when used to treat fine fraction-containing sample, this method may as well provide an improved concentrate grade.

Jan 1, 1995

By S. Veeramasuneni, Qingxia Liu, Susan Dichter

Gypsum (CaSO4-2H2O) is an abundant and naturally occurring mineral. Under elevated temperatures (250 to 300°F) gypsum loses its crystalline water and is converted to hemihydrate (CaSO4 -0.5H2O). The hemihydrate form is also called plaster that is widely used in wall- board, joint compound, and many other industrial applications. At temperatures higher than 450°F (up to 1,200°F), gypsum loses all crystalline water and is converted to anhydrite form (CaSO4). The loss of crystalline water at elevated temperatures is an endothermic reaction. This property makes gypsum an attractive filler and fire retardant in certain thermosetting plastics. The applications of gypsum in plastics, food, pharmaceutical, and paper coatings will be reviewed in this paper. The future of synthetic gypsum, a by product of various industrial processes, will also be discussed.

Jan 1, 2003

By I. Iwasaki, J. N. Orlich

The effect of slurry rheology and ball coating characteristics on the abrasive wear of grinding media and the rate of grinding were studied using -10 mesh quartzite in laboratory marked ball wear tests. Pulp viscosity was found to be closely related with both the thickness and physical characteristics of the coating affecting abrasive wear. The packing density of particles at the ball surface was the primary determinant of wear while the grinding rate was more dependent on viscosity and thus the ball coating thickness. The optimum grinding rate was achieved when the coating thickness was about twice the largest particle size.

Jan 1, 1988

By Alexander B. Ikonnikov

All known bauxite deposits in China occur in its eastern half, and almost all of them are found in the Carboniferous and the Permian. They are of platform origin, but contain diaspore as the major ore mineral. There is only one known deposit composed of gibbsite. The most valuable deposits are sedimentary ones formed in local depressions on the edges of platforms during marine transgressions. They lie on Upper Cambrian or Middle Ordovician limestone that was weathered for a long period of geological time. Generally, Chinese bauxites are low in iron, and have a rather low alumina/silica ratio.

Jan 1, 1984

By S. N. Mukherjee

Maintenance of equipment in Longwall faces plays a vital role in face performance. This is more prominent when shortage of spare parts and trained personnel occurs. A study was made in an operating Indian Longwall face for identifying the types and meantime between failures. Though the duration was not enough and study was not very elaborate, it revealed certain interesting facts. The machine availability was found to be poor, though a maintenance schedule was followed. Failure of simple parts like AFC chain connectors even resulted in loss of production of 10 times the complete chain cost. This pinpoints that a proper maintenance schedule is to be developed considering the human factors and local conditions existing in the particular country. Operations research techniques could be used in the process.

Jan 1, 1989

The new generation of computer environment provides mineral processing plants with convenient tools to store and retrieve or to analyze on-line process variable values as given along time by the various sensors installed in the plant. The paper describes the application of classical tools, such as time series analysis, to retrieve the hidden information contained is such data. The concepts used in single signal processing (autocorrelogram, power spectrum, ARIMA descriptors) and multi-signal processing (cross-correlogram, cross-spectrum) are briefly reviewed. Some examples are given to illustrate their application (sampling, data filtering, process behaviour prediction, process evaluation, data synchronisation). Examples are taken from mixing, flotation and leaching processes.

Jan 1, 1990

By Stanislaw Wasilewski, Zdzislaw Krzystanek, Boleslaw Firganek

The experimental system for mine venti1ation control in Staszic colliery has two - level structure. In the lower - measuring 1evel the existing computer - based early fire detection system has been used completed with a number of additional sensors needed for ventilation parameters monitoring. The higher 1evel is a secondary computer equipped with a suitab1e dedicated software performing data processing according to the control a1gorithm. Direct control of air flow in a selected mine district is performed by means of a remotely controlled automatic regulator. Apart from functional tests of the system and its elements some research work has been carrying out in the colliery based on observations of transient effects caused by changes in air flow distribution.

Jan 1, 1989

By Victor F. Hollister

This report summarizes data available on the Fort Knox gold deposit to the end of 1989. It is presented courtesy of Fairbanks Gold, operator of the Fort Knox mine. The ore body and the data base are being expanded in 1990, but this summary is pertinent for inclusion in a case history volume that, in part, stresses porphyry-type deposits. Fort Knox is a pluton-hosted gold deposit 22.5 km (14 miles) northeast of Fairbanks, AK. It is easily accessible from Fairbanks, and ultimately it will be the largest open pit gold mine in Alaska. The Fort Knox pluton has an interesting historical record, and it has been discovered at least twice. Fig. 1 shows the geology and location of major plutons in the Fairbanks mining district.

Jan 1, 1991

By Paul Grisley

Air-supported belt conveyors-conveying systems that replace troughing idlers with a film of air-were a revolutionary concept when introduced in the 1970s. But high installation and operating costs limited their application. Now, system refinements have led to successful applications, even under the challenging conditions of mines and process plants. In this presentation the author will discuss the latest developments in the engineering of these systems, including the ability to retrofit existing transfer points with modular air conveyor components. Air conveyor applications and limitations in mineral-handling operations will also be examined.

Jan 1, 2002

By S. Pignolet-Brandom, E. Fregeau-Wu, I. Iwasaki

To recycle steelmaking slags for their iron, manganese and lime contents, removal of the phosphorus-bearing dicalcium silicate and calcium phosphate is essential. Slow-cooling of slags was necessary to promote sufficient grain growth to achieve liberation. In situ grain size distribution determination showed that a high soaking temperature, a long soaking time, a very slow cooling rate and the addition of fluorspar promoted grain growth. High gradient magnetic separation on slow-cooled slags removed much of the dicalcium silicate. Liberation modeling was used to discuss the breakage and beneficiation characteristics of the slow-cooled slags.

Jan 1, 1993

By Oliver Gutsche

High-pressure roll mill comminution of heterogeneous multicomponent feeds was simulated with artificial limestone-quartzite mixtures using a piston-die press. The influence of heterogeneous interactions between components of the mixture on grinding path, energy utilization and energy split have been examined. Primary fractures are governed by differential fracture strength and attrition resistance of the components at heterogeneous contacts; subsequent secondary and tertiary fracture events are governed by coarse-fine interactions in the particle-bed. The weaker component is preferentially ground out of the feed size fraction and concentrates in the fines. Energy split among the components in the mixture is a function of their relative fracture strengths. It doubles for limestone and decreases by a factor of 5 for quartzite over the entire range of the mixing ratio.

Jan 1, 1995

By Timothy M. Dyhr, Marie Garrett

The Cannon Mine gold project has been perceived as unique for being developed in an area characterized by orchards and suburban residences. The Cannon Mine was permitted and developed successfully in this setting. However, the ability of companies to permit, develop and operate mines in mated areas is becoming more difficult as a result of opposition by residents and increasingly stringent regulation. The challenge to the mining operator in the future on otherwise economically attractive mineral deposits will be the ability to explore and develop these types of projects successfully and cost- effectively

Jan 1, 1987

By Y. Topkaya, R. E. Johnson, B. R. Palmer, R. B. Bhappu, Ronald J. Roman

The hydrodynamics of the leaching solution in leach heaps is known to be one of the important variables in the performance of the heap. The solution hydrodynamics are also important in the decommissioning of a heap where the aim is to flush out the residual dissolved metals and the remaining reagents. Chemical engineers have studied the hydrodynamics of "trickle bed" reactors for 40 years in an attempt to relate the performance of trickle bed reactors to flow conditions. Their work is reviewed with emphases on areas of similarity to heap leaching.

Jan 1, 1993

By Ali Soltani, Scott Santti

The Gold Quarry Mine is a large scale open pit mine located 11.3 km (7 miles) north of Carlin, Nevada. The operation consists of an open pit mine, two milling facilities, a leach crushing plant, and three dump leach pads. Gold Quarry is operated by Newmont Gold Company, which is 90.1% owned by Newmont Mining Corporation, a Denver based company. The property is the largest of the three gold producing properties operated by Newmont Gold Company on the famous Carlin Trend. This paper will give a general overview of the Gold Quarry mining facilities and detail mine operating practices. Specifics on cost saving ideas being implemented and those under investigation will be discussed.

Jan 1, 1989

By David Royston

Conventional straight-radial SAG mill pulp lifters suffer from incomplete discharge of the rock portion of the charge. The resulting backflow of undischarged rock limits pulp lifter performance and is the major source of wear in pulp lifters. Backflow is increased in pulp discharge cone systems where multiple channels converge towards the central diversion cone. This paper covers recent experience with pulp lifter and discharge cone design supported by a single particle motion model that illustrates the discharge and backflow characteristics of pulp lifters, including the impact of discharge cone configuration.

Jan 1, 2005

By Fred D. Wright

In this paper the principal theories used to design roof bolting systems are presented and discussed. Then the characteristics of various types of roof bolts are presented and finally the interaction between rock and roof bolt characteristics on choice of roof bolts is discussed. Theories can be considered design tools which may or may not be appropriate for a specific situation. It is good for a design engineer to have a number of such tools available and also important that he understand their good features as well as their limitations. Hence, some of the principal theories and classification systems used for design of roof bolting systems are discussed first.

Jan 1, 1982

By A. Maréchal

It has been shown since a few years that the problem of estimating recoverable reserves should be solved by using specialized statistical techniques : whenever the selected blocks are chosen without any other constraint than a cut-off grade criterion, the problem of estimating the corresponding tonnage-grade curve is resolved by estimating the local histogram of block grades. Two major statistical techniques are currently used by geostatisticians to estimate local histograms : the "average conditional distribution" technique (Parker, Journel, Dixon 1979) and the disjunctive kriging technique. (Matheron, 1976, Jackson, Maréchal, 1979). Both have proved to be applicable in practice, with their pros and conconcerning their practibility and versatility.

Jan 1, 1982

By G. G. O. O. Uwadiale

A number of Nigerian iron ore deposits have been upgraded to the specifications of concentrates for the blast furnace and the direct reduction iron- and steel-making plants. Depending on the mineralogy of the ore deposits, the techniques of oil agglomeration, magnetizing reduction, washing and scrubbing, gravity concentration, and reverse froth flotation have been utilized. A mode of distributive management of the deposits, in the direction of their technoeconomic utilization in the country's developing iron and steel plants, is presented.

Jan 1, 1990

By R. Costa, A. Kozak, B. Fukuhara

Introduction The Jacobina mine is located in the state of Bahia in northeastern Brazil approximately 330 km northwest of the state capital city of Salvador and 9 km from the town of Jacobina. The Jacobina Mine (Figure 1) is owned by Jacobina Mineração e Comércio, a wholly owned subsidiary of Yamana Gold Inc. The gold mineralization of the Jacobina mine is hosted within quartz pebble conglomerate reefs of the Serra do Córrego Formation which together with the Rio do Ouro Formation forms the Serra do Jacobina mountain chain. The Serra do Jacobina mountains have been mined for gold since the late 17th century. Since the 1970’s, the Jacobina mined has been operated by Anglo American, Williams Resources Inc., Desert Sun Mining Inc. and now Yamana Gold Inc.

Jan 1, 2007