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By Vanessa M. Torres, Lafayette C. L. Freitas, Evandeo C. Silva

This paper shows two applications of artificial intelligence models in process development. In the first application, a heuristic fuzzy correlation can predict flotation behavior in bench scale based on feed characteristics for a high variability copper ore, as well as to predict plant performance for a feasibility project evaluation, minimizing its risk. The second case study shows the use of neural networks to model the iron ore sintering, correlating ore characteristics and operational parameters with sinter properties. With this application, CVRD aims to establish a new step on iron ore product evaluation and customer support.

Jan 1, 1998

Geopolymerization is a process by which Al-Si minerals undergo dissolution and polymerization in an alkaline solution to form a monolithic material with a high mechanical strength (Davidovits, 1991, 1994). In this study, the factors affecting the geopolymerization of Na feldspar (albite) and K -feldspar (microcline) were investigated. It was found that both Na feldspar and K -feldspar are reactive in geopolymerization with the resultant geopolymers showing a high compressive strength. The leaching ability, the proper molar ratio of Si/Al in the geopolymeric gel phase and the higher average hardness of the undissolved particles remaining in the geopolymers are found to greatly affect the ultimate compressive strength of the formed geopolymers. Key words: Geopolymerization, Mineralogy, Albite, Microcline

Jan 1, 2003

By J. Mark Richardson

Modern mining operations are increasingly affected by complex economic factors. Broad and rapid fluctuations in metal prices, rising operating costs, socio-political trends and the inherent technical difficulties encountered in most operations, all can combine to quickly change once-profitable ventures into money-losing propositions. Accurate knowledge of metal inventories during all phases of an operation has become essential to wise management decision-making. This paper reviews key elements of metallurgical accounting: sampling theory, measurement technology and computerized data adjustment. Application of current technology to the reconciliation of a hypothetical operation is discussed.

Jan 1, 1991

By F. L. Jackson

When using perlite as an insulation, it is important to determine the requirements for different applications as this influences the processing of the perlite. In cryogenic application, perlite properties of low density and fine particle size are desirable, while loose fill insulation applications require similar properties and water repellency. However, in perlite insulating concrete applications, a coarser particle, of higher density, is required to provide improved compression strength. The essential properties of perlite including particle size, density, and surface treatment are discussed in relation to the various insulation applications. Also, typical mineral processing and manufacturing techniques are reviewed.

Jan 1, 1987

By S. K. Kawatra, T. C. Eisle

In froth flotation of phosphate, it is important that the flotation be as selective as possible in order to maximize grade and recovery without adding additional stages of flotation. Flotation columns provide a means for improving the selectivity compared to conventional flotation machines and are of considerable interest for phosphate processing. The selectivity of a flotation column is largely limited by the degree of back mixing of tailings into the froth zone, and its recovery is limited by the degree of short-circuiting of feed to the tailings. The horizontally baffled flotation column was therefore developed to minimize back mixing and short-circuiting without introducing problems with plugging or reduced capacity. The introduction of horizontal baffles to a column reduces both entrainment of feed water into the froth and short-circuiting of feed to the tailings, which improves the column selectivity. The results of horizontally baffled column flotation of phosphate are presented for fatty acid flotation of phosphate, with comparison to conventional flotation using the same reagents.

Jan 1, 1999

By P. C. Thakur

The history of coal mining in the United States of America and the rest of the world is replete with mine explosions and consequent loss of lives. Serious efforts in the USA to recover methane prior to mining and post mining started about forty years ago. CONSOL Energy Inc. and government agencies, e.g., the erstwhile US Bureau of Mines developed several techniques of methane drainage, such as in-mine horizontal drilling, vertical gob wells, hydrofracing of vertical wells and horizontal drilling from surface. With the current technology, thirty to sixty percent of total methane emissions from a mine can be captured making the mines much safer and more productive. Drained methane is often marketed to defray the cost of methane drainage. This paper is an anthology of these developments and describes how coalbed methane, which used to be a bane, has become a boon for the coalmining industry.

Jan 1, 2003

By M. A. S. Martins, J. C. Guillaneau

Steady-state simulation has been proving its usefulness and efficiency in process design and optimization for many years. Steady-state simulation is a very effective approach for plant design since it enables a great number of hypotheses to be considered regarding flowsheet, equipment etc., the processing equipment and material handling equipment to be sized, and the configuration of almost optimal industrial plant to be attained in a very short time. This paper will present the basic principles of mineral process simulation methodology and some real case applications of their capabilities in several complex ores in Brazil.

Jan 1, 1998

By R. F. Hüttl

World-wide Germany is the leading lignite mining nation. Most of the lignite is produced in opencast operations. However, opencast mining causes enormous impacts on natural ecosystems and even on entire landscapes. The extensive production of lignite particularly in eastern Germany results in large devastated areas, which so far have been reclaimed only to some part. For the restoration of the post-mining area of more than 80,000 ha the major land use option is the reestablishment of forest ecosystems. However, adverse site conditions of the post-mining landscape such as extreme soil acidification and salt concentrations call for specific recultivation practices. Therefore, after the German reunification new reclamation and reforestation concepts have been developed for these brown coal areas of eastern Germany by the Collaborative Research Center (SFB 565) at the Brandenburg University of Technology at Cottbus (Germany). As a case study our comprehensive investigations into forest ecosystem development on terra nova in the Lusatian lignite mining district, south-east of Berlin, will be presented.

Jan 1, 2003

By Lynn B. Hales, Randy A. Ynchausti

Object-oriented technologies have been developed to more closely model the way we think about the world and our natural approach to solving problems. Higher levels of abstraction, generalization and classification are benefits of an object-oriented approach. Object-oriented programming, design, and expert systems are part of this technology which is shaping the future of real-time supervisory control. Goals of real-time supervisory control systems include: minimizing variations in process operations, improving efficiency, maximizing production, and implementing procedures for starting and stopping the process. Incorporating object-oriented technology in design, development and implementation of real-time supervisory control systems provides new opportunities for these tasks. This paper discusses some of the opportunities and challenges of implementing real- time supervisory control using an object-oriented expert system for a rougher flotation circuit

Jan 1, 1993

By Ed Van Eeckhout

The rockburst monitoring system at the Sunshine Mine has recently been improved to increase the certainty of burst locations and to output location results in a manner amenable to easy interpretation. Three methods of location calculation were used: a computer code provided with the hardware in-place (the MP-2501, a code based on the least-squares method (Blake et a1, 19741, and a nonlinear iterative code written by the principal author. The more accurate locations are given by the latter two codes, but still are only correct to within about 100 ft. This error is due to uncertainties introduced by the geologic and mining variations versus the assumptions made in the location codes. Software was then written to make two-dimensional plots of burst location by level, so management could monitor problems easily.

Jan 1, 1986

Projections of coal reserves in Central Appalachia are essential for long-term planning in the region. Annual production is declining in states such as Virginia. And minable reserves for the Central Appalachian coalfield are challenged by difficult geological, mining and market conditions. To project coal mining longevity in this region, interviews with mining companies were conducted to determine and assess technical and economic factors that affect coal seam minability. This information was ap- plied to seam and coal reserve data developed by state and federal governments. The results were analyzed to determine the effects of various factors on the overall minable coal reserve base.

Jan 1, 1998

By Vas Choudhry, Randhir Sehgal

Conventional clean coal technologies which consist of coarse coal cleaning by gravity methods and treatment of natural fines by flotation can only remove a portion of the pyritic sulfur and ash in the coal. Higher (+90%) pyritic sulfur rejection is attainable when coals are ground to ultrafine sizes to enhance liberation of the mineral matter and then cleaned. However, cleaning of coal at very fine sizes poses a number of unsolved problems, the chief one being the loss of cleaning efficiency. This, of course, means that liberation of pyrites does not always equal its rejection. In addition, the dewatering of fine- cleaned coal, and its handling, transportation, and acceptability to the utility industry a1 so pose considerable technical and economic problems, especially when compared to the FGD alternative. This paper addresses some of the critical issues involved in the cleaning of ultrafine coal s.

Jan 1, 1989

By J. Cassells, N. Chrisman, R. Arnold, P. Rusin, L. Quintana

Toxic substances in On solutions can retard biological leaching of sulfide dump ores. On solutions were ana1yzed for metals, organics and chloride and showed inhibitory concentrations of aluminum, manganese and chloride. Inhibition of bacterial activity by the solid fraction of On solution with and without the organic constituents, was evaluated. Bacterial toxicity was evaluated by monitoring bacterial numbers, pH, Eh, and rates of iron oxidation. The On solution solids were toxic at 50% to 60% of their field concentration. Most of the toxicity of the On solution was due to the organic fraction. Different solvent extraction (SX) reagents show varying degrees of inhibition of T. ferrooxidans. Bacterial inhibitory effects of carriers and lixiviants used in the SX plant should be determined so that entrained SX reagents do not retard biological dump leach systems. The reagents used should be the most cost-effective and the least toxic.

Jan 1, 1996

By A. J. Surtees, M. P. Evans

This paper discusses the development and application of sophisticated monitoring equipment used to measure the operating parameters of conveyor systems. With the radical reduction in price of computer hard- ware and software during the last decade and an associated increase in memory capacity, the concept of continuous conveyor monitor is now a reality. With this tool, the various problems normally encountered in large conveyor installations can now be avoided at an early stage. • The four main areas of application are: • Design verification • Hand-over certification • Preventative maintenance and increase of system availability Failure analysis The paper introduces the techniques used and gives examples where the service has been used.

Jan 1, 1996

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 Xinyang Xu, Jirun Xu, Changlie Deng, Kang Yan, Luo Qian

Cake filtration is a complex process and the cake constructure is very difficult to describe in theory. Cake constructure parameters, such as the cake prosity, pore size shape and even its distribution, are main factors influencing the filtration results but have not been thoroughly understood yet. In this paper the fractal theory, an effective mathematical method in describing the self-similar phenomenon is used to investigate the filter cake constructure, and the scanning electron microscope and automatic image analyzer are used to measure the cake constructure. Cakes which formed in different condition are examined and the fractal dimension of the cake are calculated. The study shows that the constructure of the filter cake can be approximated by Sierpinski fractal geometry and that the fractal dimension of filter cake, related to the particle characteristics, slurry concentration and filtration pressure is a good parameter to describe the pore size distribution and the cake penetrability.

Jan 1, 1995

By R. H. King, R. E. Cameron

Mine managers need better information to locate new opportunities and then to assess the effect of their decisions. We are developing the Intelligent Decision Support System (IDSS) and its two major modules, the Pattern Recognition System (PRS) and the Knowledge Representation Subsystem (KRS) to automatically provide the information from monitoring system sensors. This paper focuses on the KRS Algorithms that extract key information from lists of time-study type event sequences. Because a static system cannot operate effectively in a dynamic mining environment, we are prototyping an index- based technique that allows the system to adapt itself to this dynamic environment.

Jan 1, 1991

The definition of sustainable development is often taken from the so-called “Brundtland” report, requiring that activities of the current generation not detract from the potential welfare of future generations. Mining is often held up as unsustainable in this regard, since the extracted resource is non-renewable. Yet Brundtland’s definition of sustainable development also requires that the current generation address the disparity in welfare across the globe, a facet of Brundtland’s report that most have ignored. This paper examines the impact of mining on the welfare of the poor, empirically assessing mining’s contribution to this second facet of sustainable development.

Jan 1, 2004

By Richard Hogg, Heechan Cho

Investigations of long-time grinding of fine quartz (to about 80% passing 0.35 pm) in a 0.6 liter stirred-media mill are described. Breakage rates and primary breakage distributions have been determined based on extensive characterization of the ground products by laser scattering/diffraction and gas adsorption. The results indicate that, while there is qualitative similarity between the breakage parameters for ultrafine and conventional (coarse) grinding, there are important, quantitative differences. In particular, it is found that primary breakage distributions become significantly narrower in the submicron sizes. The trend can be described using double-truncated log-normal distributions in which both a maximum (breaking) size and a grind limit are specified. The breakage distributions become progressively narrower as the size being broken becomes finer. Breakage rates follow a typical, consistent pattern in which the rate decreases with size according to a simple power law. Further decrease in the rates seems to occur after very long grinding times when the entire mill contents become finer than about 1µm. The effect is explained as a result of changes in the rate/size relationship in the submicron range.

Jan 1, 1995

By Keith G. Wallace, Malcolm J. McPherson

In order to model accurately a mine ventilation system in an existing mine, it is necessary to determine the resistance to airflow in all main airways. This is accomplished by measuring the airflow and pressure differential in each airway. Gauge and tube methods have been used to determine pressure drops in ramps and level airways. However, it has rarely been used in evaluating the frictional pressure drop in shafts. Because shafts commonly have the highest pressure loss in mines, it is critical that the resistance of these airways be determined accurately. This paper describes the theory and practice of using the gauge and tube method for determining the pressure drop in shafts. The pros and cons of using this method are discussed as well as a comparison between the gauge and tube and barometer measurement techniques. Case studies showing the accuracy of shaft gauge and tube measurements are also presented.

Jan 1, 1991