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By B. M. Moudgill, T. V. Vasudevan

Marine sedimentary deposits account for 80% and igneous deposits 17% of the total world output of phosphate rock. The phosphate mineral is well crystallized and exhibits a greater floatability in the igneous deposits than the sedimentary ores. Both silicates and carbonates contribute the major gangue associated with the sedimentary ores. Although removal of silica from sedimentary phosphates by froth flotation has been in practice for several decades, with the depletion of high-grade reserves, new attempts are being made to improve the efficiency of current silica removal technology and to develop new processes for beneficiation of phosphate ores associated with the carbonate gangue. In this paper, recent developments in processing of sedimentary phosphate ores containing carbonate and silica gangue are discussed.

Jan 1, 1987

By M. Prasad, G. M. Rao, A. K. Majumder, T. C. Rao

Froth flotation was employed to beneficiate a lean-grade siliceous rock-phosphate ore containing fluorapatite, the phosphate-bearing mineral. The main gangue minerals were quartz, iron oxides and aluminum oxides. After the rougher stage, four cleaning stages were required to upgrade the ore. The liberation size of the phosphate mineral was below 200 mesh, The reagent scheme consisted of commercial-grade sodium silicate and sodium oleate. The effect of reagent dosages, number of cleaning stages and pulp density on the efficiences of separation were studied systematically. A flowsheet was proposed for the processing of low-grade siliceous phosphate ore containing 12.1% P2O5, 55.36% SiO2 and 15.45% CaO. The flowsheet provided a useable phosphate concentrate containing 34.18% P2O5 and 14.20% SiO2 with a P2O5 recovery of 70.4% (the weight yield was 25.0%).

Jan 1, 1999

By Michael E. Mcllwain, Lee O. Nelson, Robert D. Rogers, James H. Wolfram

Examination of the economics and environmental consequences associated with phosphate fertilizer production documents the necessity for development of innovative production technologies. Evidence of phosphate ore's susceptibility to microbial alteration indicates that it will be an ideal candidate for industrial-scale bioseparation. There are at least two applications for the biosolu- bilization technology: (1) an industrial-scale bio- process similar to the presently used wet acid process and (2) production of small prills (bio- bead) containing unprocessed rock phosphate and the biological ingredients necessary to promote phosphate solubilization. At the present stage of development, the biobead technology is the preferred application. It is an energy-efficient "green" technology that will dramatically reduce the amount of solid waste and air emissions produced by the phosphate industry.

Jan 1, 1999

By T. V. Vasudevan, J. Blaakmeer

Adsorption experiments were conducted at two different solid loadings to investigate the mechanism of oleate adsorption on apatite. Adsorption density at pH 10 was found to be dependent on solids loading in an oleate concentration region where surface precipitation could occur. Analysis of adsorption isotherms indicated three distinct regions of adsorption. In region I (below the region of calcium oleate precipitation), molecular adsorption was observed. Simultaneous molecular adsorption and surface precipitation occurred in region 11, while surface precipitation was predominant in region I11 along with some bulk precipitation. Correlation between flotation of apatite with sodium oleate and the mode of oleate interaction with the surface is established.

Jan 1, 1988

By Michael J. Rinker, R. V. Nicholson

Waste rock and tailings from a proposed nickel-copper mine were evaluated extensively for potential on-land and under water disposal. Standard humidity cell and column tests were conducted over a two year period and underwater tests were conducted for more than one year. Nickel concentrations or release rates from the waste were consistent with nickel to sulphur ratios in the solids. This relationship provided a tool to assess the risk of metal leaching in wastes using nickel and sulphide assays. Nickel release and mobilization was found to occur for both oxidizing leach tests and under water tests even when pH values exceeded 7.0. Geochemical model calculations showed that iron oxyhydroxide solids can scavenge nickel from leachate and that the nickel inventory can be released from solids at relatively lower, but neutral pH values.

Jan 1, 2000

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

By J. Andersen

The very large quantities of energy used for size reduction in the minerals processing industry necessitate the accurate prediction of comminution machine power draw for optimum plant design. The JKMRC has developed effective models for predicting ball mill, autogenous mill, semi- autogenous mill and crusher power draw. When combined with comminution models they provide a powerful tool for evaluating not only the size reduction performance of a plant design, but its power utilization efficiency as well. This paper describes the structure of the mill and crusher power models. Data from a wide range of equipment types are presented which illustrate the accuracy of these models.

Jan 1, 1992

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 Christopher Haycocks, Randolph Reed, Erik C. Westman

The industrial Source Complex (ISC3) model is the accepted standard used to predict emissions of particulate matter less tan 10µm in diameter (PM10) from industrial operations. This model, however, over-predicts PM10 emissions from surface mining operations, making permits harder to obtain. The over-prediction is likely due to the fact that the model applies emissions from mobile (dynamic) sources to stationary (static) areas. Utilizing a Gaussian dispersion equation, a Dynamic Component Program was created to correct the over-prediction of the model and results in a much more realistic modeling of actual conditions from mobile sources.

Jan 1, 2002

By C. J. Pritchard

Productivity improvements reduced the number of continuous miner sections from seven to three while maintaining full productive capacity. So a decision was made to test an advancing tailgate ventilation system on the shortwall mining section. Having the shortwall mine its own return air system has freed the third mining section for more productive, less costly mining. The advancing tailgate has provided effective ventilation across the face and gob with acceptable pressure losses. The low-productivity, tailgate-development, continuous-miner section has been transformed into to a high-productivity, development-retreat section that is also available for long-term mine development duties, increasing mine planning flexibility.

Jan 1, 1991

By Donald S. Skufca

This chapter focuses attention on major factors pertaining to plant design and general arrangement of equipment. Considered are efficiency of operations, coordination of maintenance and repairs, plant testing of reagents and possible future plant expansions. The design and general arrangement of equipment considers accessibility for maintenance and isolation for repairs, minimum personnel for operations and cleanup, safe working conditions with minimum interruptions to operations. The constant introduction of new reagents requires eventual plant testing and the manner of isolating a “line” or part of the facilities to allow comparisons in the testing of new reagents is discussed. As technology improves and process changes occur, additional equipment or plant expansions are inevitable. Space for these eventualities must be considered while the general arrangement drawings are in the development stages.

Jan 1, 1986

By G. T. Adel

The growing interest in column flotation has created a need for a fundamental scale-up procedure which is capable of meeting the necessary design and control criteria for industrial columns. Unfortunately, most of the avail able scale-up procedures deal with column diameter only and not overall column volume. Current work focuses on the effect of bubble size distribution and air hold-up on the scale- up of column volume. A series of pressure transducers has been used to measure air hold-up along the length of a bench-scale column. These measurements have been used to validate a mathematical model of the air phase. In addition to scale-up, the model appears to have the potential for use in control of air hold-up and bubble size.

Jan 1, 1990

By M. S. Celik, A. Aslanbas, B. Pehlivanoglu, R. Asmatulu

The principal impurities in some feldspar ores are titanium and iron, which impart color and degrade the quality of the ore. Mineralogical investigations indicate that, while titanium originates mainly from rutile with small amounts of sphene, iron originates mainly from mica minerals. Fatty acids, particularly oleic acid, are extensively used, with reasonable success, in the flotation of colored minerals from feldspar ores. In this study, potassium oleate, oleoyl sarcosine and hydroxamate were used to float colored impurities both before and after magnetic separation. Oleoyl sarcosine is found to exhibit better results compared to other reagents. Magnetic separation followed by flotation is found to produce a feldspar concentrate of superior grade.

Jan 1, 2002

By J. H. Tylczak, R. Blickensderfer, D. J. Singleton

As part of its research on wear of mining and mineral processing equipment, the US Bureau of Mines evaluated the erosion-corrosion characteristics of 12 alloys in phosphoric acid waste water. Tests were conducted on 2- and 5-cm-diam specimen8 in 12- and 60-cm-diam ball mills by grinding phosphate rock in gypsum pond water with an initial pH of 1.6. For comparison, grinding tests also were conducted in tap water. Static corrosion tests in gypsum pond water also were carried out. For all alloys tested, the wear by erosion-corrosion was greater than the sum of erosion plus static corrosion. A low-alloy, high-carbon steel and a high-manganese, nitrided stainless steel were the most cost-effective materials

Jan 1, 1987

By Simon D. Handelsman

Technical co-operation activities of the Department of Technical Co-operation for Development of the United Nations Secretariat have included the introduction of electronic data processing techniques in mineral sector projects for several years; computers have been provided to countries in Africa, Asia and Latin America. Advisory services are provided to interested developing countries at their request concerning applications for various uses in mineral sector activities. They include advice on appropriate hardware and software depending upon the requirements of the particular Government. The Department's activities in this area are described. The input from a Group of Experts on this subject convened by the United Nations, and their conclusions and recommendations, are also discussed.

Jan 1, 1986

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 Selamet G. Ercelebi, Mahmut Yavuz

An inherent aspect of longwall mining is moving the equipment from a mined-out panel to a newly developed panel. Moving times may be reduced by detailed preplanning. A very useful tool for planning is MS Project. Using MS Project, one can efficiently plan, manage and coordinate a project from conception to conclusion. The critical path analysis identifies potential critical activities which may cause excessive time delays. Changes to the tasks on the critical path can have significant impact 0.n the completion of a project. Assigning additional resources to these tasks (either moving labor from other tasks to critical tasks or providing labor overtime work) may reduce the move time. Simultaneous activities are the candidates for moving the labor from an activity to another. Each time a change is made, the critical path should be recalculated. MS Project quickly recalculates schedules and lets you see how changes in one part of the project will affect the overall plan. In this fashion it is possible to minimize the longwall move time.

Jan 1, 2002

By R. Larry Grayson

In an interdisciplinary research effort at West Virginia University, the Mine Management Support System (MMSS) is being developed as a window-based shell that may be used for the integration of a myriad of applications software. A number of integral components that focus on enhancing operational decision making are being developed as well. MMSS includes a flexible and robust work scheduling system that assigns the "best," qualified workers to the highest priority jobs on a shift while considering many practical and dynamic parameters affecting the assignments. A consultation system has been developed to help solve operating problems using management-preferred responses and the latest available information on operations.

Jan 1, 1992

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 M. T. Ityokumbul

Flotation columns and their variations are increasingly replacing conventional cells in mineral-processing circuits. While the operational characteristics of columns differ from those of conventional cells, the same scale-up methodologies are being employed. This practice may be attributed to a poor understanding of the factors that control throughput. The use of tall flotation columns is frequently justified because of the need for an increased particle residence time. However, it is shown that longer particle residence times alone do not translate into increased recoveries. In this paper, throughput data from several industrial flotation-column installations is presented. Also, an attempt is made at using dimensional analysis to provide a scale-up methodology for the factors controlling column throughput.

Jan 1, 1997