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By Anna Marabini

This paper provides a summary of the studies performed over a period of more than fifteen years by the Italian National Research Council's Mineral Processing Institute in Rome to develop applications for the use of chelating reagents in the flotation of metallic minerals. A description is given of the various phases through which the studied progressed, starting with the combined use of commercial chelating reagents and a neutral oil and then moving on to the synthesis of new long-chain chelate collectors for the flotation of sulphide and oxidized Pb, Zn and Cu minerals. After a series of preliminary tests which confirmed the possibility of floating various metallic minerals with commercial reagents containing chelating groups exerting specific action on given cations, the studies were addressed to the development of a theoretical method of choosing chelating groups that exert selective action on one metallic mineral rather than others. The theoretical approach was based on thermodynamic data concerning the chemical equilibria in solution. The validity of the method has been proved in numerous cases by flotation tests on pure minerals. Subsequently the research was directed towards the design and synthesis of reagents with a mixed aliphatic-aromatic structure containing chelating groups for Pb and Zn and an alcoxyl chain of various length, position and configuration. The flotation results obtained on oxidized and mixed Zn-Pb ores provided interesting pointers for designing the nonpolar portion. The structural criteria identified via these studies were interpreted on the basis of chemical and steric considerations. A description is given of a new synthetic chelate collector which is effective in the selective flotation of Cu minerals from complex sulphides. The fact that this reagents is more selective than xanthate is demonstrated by comparative flotation tests on actual ores.

Jan 1, 1994

By A. T. Stroebel

Diatomite deposits, the skeletal remains of tiny aquatic plants called diatoms, are found in many parts of the world. Only a few of these de- posits are of commercial value. Open pit mining is used in nearly all deposits now being worked. Processing methods range from simple drying, crushing, sizing and packaging to carefully controlled and highly sophisticated calcining and air classification procedures, employing the latest control and testing techniques. The major uses of processed diatomite are in filtration as filter aids and fillers and extenders.

Jan 1, 1979

By Ruichen Ren, Xu Han, Caixia Li, Zengchuan Yue

In this paper, the size-density distribution of coarse middling coking coal (CMCC) with different grinding fineness and flotation concentrates was investigated. Then, the flotation behaviors and liberation characteristics of different size-density fractions in ground CMCC were analyzed, and the different size-density fractions were divided into five categories: mostbeneficial, secondary-beneficial, poorly liberated, insignificant-pollution, and serious-pollution. Based on the content of particles with different liberation characteristics, an evaluation index of the liberation characteristic of ground CMCC, namely, the liberation perfection index (LPI), was proposed. The results indicated that grinding changed the size-density composition of CMCC, which affected the flotation performance. Insufficient grinding and overgrinding were not beneficial to flotation. Insufficient grinding caused a higher content of poorly liberated particles and a lower content of most-beneficial particles. Overgrinding increased the content of serious-pollution particles and reduced the content of most-beneficial particles. The size order of the LPI values of different ground CMCC was consistent with the flotation efficiency, and the LPI values of the other two similar samples were overall positively correlated with their flotation performance, suggesting that the method is universal.

Feb 14, 2023

By Norm Greenwald

The Environmental Protection Agency ("EPA") has been attempting to develop a federal regulatory program for mine waste under Subtitle D of the Resource Conservation and Recovery Act since 1986. Recent regulatory and legislative events are now bringing this goal closer to reality. This paper discusses the mining industry's perspective on a number of the issues currently being addressed at EPA's Policy Dialogue Committee and in Congressionally-sponsored negotiating sessions.

Jan 1, 1992

By C. L. Lin

A PC image-based, on-line instrument for the measurement of coarse particle size on a conveyor belt is under development. Both the hardware and software required to implement such a system are discussed, including the interface for the special image acquisition hardware. The system concept is given with examples to illustrate the step-by-step procedure for the implementation of image-processing algorithms.

Jan 1, 1992

By C. E. Jordan

The Bureau of Mines has investigated the fundamentals of fatty acid/fuel oil conditioning for improved flotation selectivity. Both conditioning time and intensity can provide optimum flotation selectivity as well as good recovery. Traditional conditioning seeks to optimize conditioning parameters with subsequent recovery of the hydrophobic mineral. In the fatty acid/fuel oil system many silica gangue particles are also rendered hydrophobic by the flotation collector. Fundamental studies have shown that particle-particle collisions transfer the collector reagents selectively to the mineral surfaces with the highest affinity for the reagent. This mechanism deactivates the gangue particles while increasing the collector reagent loading on the selected mineral. The degree of this transformation is directly related to the number of particle-particle collisions which can be controlled through conditioning time or conditioning mixing intensity.

Jan 1, 1995

By R. Frenette, A. W. Mo, H. A. Hamza

Fine particles present major technical and economic problems to those who deal with solid/liquid separation processes. In the coal industry the problem is compounded by the large amounts of produced fines such as those present in Western Canadian coals. Flocculants in the form of high molecular weight water soluble polymers are commonly considered an effective solution for the enhancement of the separation process. These reagents are relatively expensive especially when considering a low-price commodity such as coal. Optimization of the use of these reagents is therefore an operational necessity. Six polymers were evaluated as to their effectiveness in flocculating a fine coal tailing. Results were compared with those for a reference flocculant, in-use at that time in the washery. It was shown that, in general, flocculants significantly improve the solid/liquid separation process. The ranking of the flocculants as to their effectiveness in settling and filtration indicated that the best flocculants for settling were not necessarily the most effective for filtration. Flocculants that showed the best filtration improvement were generally cationic and those best for settling were anionic.

Jan 1, 1988

By P. Soros

Rich iron ore deposits were discovered during the 1960's in the mountain range of Serra dos Carajas, State of Para, Brazil, near the headwaters of the Tocantins River some 400 miles southwest from the state capital of Belem. (See Fig. 1 and 2). The key to the successful exploitation of this deposit was the development of an efficient an economical transportation system. The rugged terrain, and the dense tropical vegetation of the Amazonian jungle and the irregular coastline with its high tidal range presented severe obstacles to the planning and building of such system. Starting in 1972 extensive surveys and studies were carried out by Soros Associates on behalf of CVRD to determine the optimum way of transporting the ore from the mine site to the markets, most of which are located overseas. Overland transportation to the coast, loading into seagoing vessels and the ocean voyage to the ports of destination was treated as an integrated system in these studies.

Jan 1, 1986

By Q. Yuan, B. Yarar

Steric stabilization is a phenomenon observed when relatively high doses of flocculants are added to fine particle suspensions. Experiments were conducted to establish conditions under which medium viscosity and the sedimentation properties of black sand components in a slurry could be controlled so as to enhance the selective sedimentation of gold grains. It was shown that black sand concentrates containing as low as 2.65 g/mt gold could be upgraded by selectively hindering the sedimentation of non-gold components in an aqueous slurry. This paper presents data describing the theory and practical implementation of this cyanide or mercury-free novel approach where gold could be concentrated by as much as 15 times with relatively high recoveries. The relationships of solids content of slurries, type and dose of polymers with the recovery process are documented. Key words: Gold, black sand, selective flocculation, steric stabilization.

Jan 1, 1993

By Joseph A. Zupanick

Methane drainage is a mature technology, now commonly practiced in many highly productive underground coal mines throughout the world. Universally, the practice of pre-draining methane will continue to grow as near-surface coal seams become depleted and mining operations are forced to exploit deeper reserves. These deeper coal reserves inherently have higher gas contents. In addition, increases in productivity and extraction rates have caused higher methane liberations per unit of time. As the cost of providing ventilation air increases, the economic justification for implementing a methane drainage program becomes apparent.

Jan 1, 2005

By S. T. Hall

The authors have previously described a method of enhancing the magnetic susceptibility of pyrite by a mild alkaline oxidative pressure leach (Hall et al, 1985). This finding was successfully applied to enhance the magnetic desulfurization of an Eastern Canadian coal (Hall and Finch, 1984). This paper reports on enhancement of the magnetic susceptibilities of iron-containing sulfides (arsenopyrite, chalcopyrite and marcasite) upon similar treatment. It also explores the application of this pretreatment in the magnetic separation of fine sulfides from oxides and other sulfide minerals. In the latter case galvanic interference effects have a serious impact on the potential use of this method.

Jan 1, 1985

By Persio de Souza Santos, Ayres Ferrelra Morgado

In this work, a sample (of about 100kg) of an ore considered as smectitic, not yet industrialized, from Lages-SC-Brazil, was tested for evaluation of its industrial applications. First, we characterize them by XRD, DTA, FRX, and CEC analysis. After this, the smectitic clay was changed to sodium form by treatment with sodium carbonate. Then, the homoionic sodium clay was tested for iron ore pelletizing agent, as binder of foundry sands, and drilling mud with good results.

Jan 1, 1998

By A. J. MacKellar

The economic viability of any project is generally assessed on an evaluation of the total capital constructed costs along with operating costs, owner's costs and market conditions. This paper will be directed to the role that Cost Engineering plays in the development of the capital costs and the cost control techniques applied thereto.

Jan 1, 1975

By L. Shwydiuk, A. Chrzanowski, W. Newcomen, G. Bastin, R. Wilkins

Automated monitoring of steep embankments allows the early detection of instability and can be used to avoid or mitigate possible slope failures. A system that uses multiple and different types of sensors has been created and successfully tested at the Highland Valley Copper mine in British Columbia. The system uses robotic total stations (RTSs) as the primary measurement sensor, with surveys repeated at predefined intervals selected to optimize operational efficiency. A methodology has been developed to improve the system’s accuracy and reliability by reducing the effects of systematic errors created by atmospheric refraction and unstable instrument and reference point positions. The inclusion of GPS sensors to monitor the RTS positions creates additional operational flexibility and maintains system integrity when insufficient reference stations are available.

Jan 1, 2003

By W. A. Zingg

Impervious zones in copper waste heaps create a problem in contacting the rock with leaching solutions. These zones are normally associated with compacted layers .formed on the surface of each lift by dump truck traffic and by disintegration of the rock exposed to atmospheric conditions. These layers are usually only a few feet in depth--but, nevertheless, act as barriers to vertical flow causing the leach solution to perch in the heap, Consequently, much of the rock remains untouched and the leach solution breaks out the side of the heap instead of continuing downward to bedrock. One solution to this problem is breaking the hard pans with explosive charges. However, to use explosives means adopting new explosive materials and methods. To use this process successfully requires finding answers to operating conditions inherent to waste heaps. Foremost among these are: (1) type and size of casing that can be used because of limitations brought about by drilling problems, caving and, corrosive conditions; (2) perforating the casing at required levels; (3) an explosive capable of being pumped; (4) obtaining detonation of the, main charges through, the wail of the casing; (5) an explosive with the ability to propagate through the voids of the rubble and one which is not affected by water, acidic solutions, or back pressure conditions from hydrostatic heads; (6) to heave and rupture the compacted zones without chambering or recompressing the waste material.

Jan 1, 1970

By K. A. Natarajan

The utility of yeast, Saccharomyces cerevisiae, in the separation of quartz from hematite is demonstrated. Yeast cells, as well as their metabolites, functioned as flotation collectors, depressants or flocculants and dispersants for hematite and quartz. Interaction between yeast and the above minerals resulted in significant surface chemical changes, rendering quartz surfaces hydrophobic and hematite hydrophilic. Mineral-specific extracellular proteins and exopolysaccharides were secreted by yeast cells when grown in the presence of quartz and hematite, respectively. Quartz could be efficiently separated from hematite through microbially induced flotation and selective flocculation.

May 1, 2012

By Colin D. Jardine

Rapidly increasing energy costs and more rigid customer quality requirements necessitate improved control of pelletizing processes. With the introduction of dedicated microprocessor-based controllers, sophisticated control strategies are now possible. A recent application of this technology at Carol Project has resulted in fuel savings, improved pellet quality, and standardization of operating procedures. This was accomplished with no production loss by the use of a "building block" approach to design and equipment selection. Details of this approach and the results obtained are described.

Jan 1, 1982

By D. A. Barr

The Galore Creek copper deposits lie in the Stikine River district of northwest British Columbia, a largely undeveloped region which possesses rugged mountain terrain with deeply incised valleys which support dense undergrowth. Timberline is normally at about 1300 m (4265 ft) and the higher levels contain glacial systems and large ice fields with peaks rising to 3500 m (I 1,483 ft). A location map of the Galore Creek area is given in Fig. 1. In the late 1920s, field parties under the direction of F.A. Kerr (1948) of the Geological Survey of Canada completed geological surveys of the district. Primary access for this work was provided by riverboats on the Stikine and Iskut Rivers. Kerr's party had to contend with extremely difficult travel conditions that required considerable backpacking, augmented by pack dogs in certain cases. Absence of ground control led Kerr to establish his own topographic maps. Among the geological data established was the recognition [ ] that small bodies of orthoclase porphyry in the district are often well mineralized with base metal sulfides. Copper mineralization in the upper Galore Creek valley, a tributary of Scud River which flows into the Stikine River some 80 km (50 miles) south of the small settlement of Telegraph Creek, was originally discovered during aerial reconnaissance by M. Morrison and W. Buckholz while prospecting for Hudson Bay Exploration and Development Co. Ltd. in 1955. Malachite- and azurite-stained out- crops in several parts of the Galore Creek watershed are clearly visible from distances of 500 m ( 1640 ft) or more. Claims were staked in 1956 and the copper showings were partly mapped, trenched, and investigated by shallow diamond drilling. Because of the remoteness of the area and higher priorities for expenditures elsewhere, no further work was undertaken and most of the claims were allowed to expire.

Jan 1, 1991

By Harold L. Lovell

Problems associated with fines (minus 6 mm, 1/4-inch) production, preparation, and utilization have long plagued the coal industry and are now more acute than ever. Continuous deep mining systems create more fines which have moisture; content greater than natural levels from dust control spraying and often add substantial levels of mineral matter due to mining selectivity constraints. Frequently, during preparation, more -fines are developed to achieve improved component liberation. Coal consumers often specify small sizes whether for carbonization, combustion, or conversion. Wet beneficiation systems process fines by several' types of unit operations, but usually must also incorporate costly and complex dewatering systems to reduce the moisture content of the products. Existing pneumatic preparation systems are constrained between product equality and yield by the sharpness of separation. These limitations become more severe with decreasing particle size and increasing feed moisture content. Control of particulate emissions, both process and fugitive, during pneumatic preparation, can be forbidding. A pneumatic preparation-process which would overcome these constraints, could be most enticing. The DryFlo system is being evaluated to quantify performance characteristics as regards these constraints.

Jan 1, 1976

By Kevin J. Ashley

Coal is deposited at a mine site in several thin seams which outcrop in rolling hills and dip at about 8° to the northeast. The deposit is located in the northeast area of the State of New Mexico in the Southwest of the United States. A drilling program was undertaken and was quite irregular. Not all of the seams appear in all of the drill holes. Some of the holes did not go deep enough, while others were drilled below the outcrop of some seams. Occasionally a seam would pinch out and not be seen in a drill hole. Also, the outcrops of the seams are buried in many places by several feet of alluvium. All of these factors make correlation of the seams between drill holes difficult. The drawing of cross sections in three directions and at many locations across the mining area have been necessary to assure the accuracy of the input data.

Jan 1, 1982