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By E. F. Schnitzer, S. R. Mamoyac, P. J. Wampler

During 1996 and 1997, Oregon experienced flooding on a scale not seen in many years. Some gravel pits located near rivers experienced erosion and, in several cases, breaches between the gravel pit and the river. Initial evaluation of several sites that experienced breaches indicates that impacts to the river system are complex and vary significantly from site to site. The impacts to the adjacent river system may be viewed as both positive and negative. Several floodplain-mining sites in Oregon located in areas of historic river flow have reverted to active riverbed. In many cases, state and federal fisheries biologists and university researchers see the resulting increase in channel complexity and habitat as favorable. The Oregon Department of Geology and Mineral Industries – Mined Land Reclamation Program (DOGAMI-MLR) is performing additional studies of the impacts to the off-channel areas that resulted from the 1996 floods. More data is needed to make sound floodplain decisions regarding mining.

Jan 1, 1999

By E. F. Schnitzer, P. J. Wampler

During 1996 and 1997, Oregon experienced flooding on a scale not seen in many years. Some gravel pits located near rivers experienced erosion and, in several cases, breaches between the gravel pit and the river. Initial evaluation of several sites that experienced breaches indicates that impacts to the river system are complex and vary significantly from site to site. The impacts to the adjacent river system may be viewed as both positive and negative. Several floodplain-mining sites in Oregon located in areas of historic river flow have reverted to active riverbed. In many cases, state and federal fisheries biologists and university researchers see the resulting increase in channel complexity and habitat as favorable. The Oregon Department of Geology and Mineral Industries – Mined Land Reclamation Program (DOGAMI-MLR) is performing additional studies of the impacts to the off-channel areas that resulted from the 1996 floods. More data is needed to make sound floodplain decisions regarding mining.

Jan 1, 1999

By J. C. Stankus

Many coal seams are associated with soft floor strata and during mine development if coal pillars are not properly designed, floor heave occurs and causes interruption of coal production. In the severe cases, the section or mine is abandoned. One of the methods for controlling floor heave is floor bolting. This paper describes the demonstration of floor bolting methods in a West Virginia coal mine. Three methods were used: (1) vertical full resin bolting, (2) floor truss bolting, and (3) floor truss bolting plus a floor cut at the center of the entry. The design of each method and the experimental results are discussed in detail.

Jan 1, 1993

By Chuang Sun, Feng Luo, Guo‑dong Li, Xue‑qing Li, Tuan He

The mining-induced failure of the coal seam floor is essential for water inrush. The mining disturbance to the floor, especially in the thick coal seam, is severe, and the water inrush risk is also higher than that in regular thick coal seam excavation. The superposition of many stresses, including in situ stress, mining-induced stress, and confined water pressure, must be considered in the prediction of the floor failure depth. This study adopted the elasticity analysis, FLAC3D numerical simulation, and on-site acoustic wave test comprehensively. The thick coal seam working face of the Zhong-Yu coal mine affected by confined water was selected as the engineering background to study the characteristics of the floor failure. Based on elastic foundation theory and the superposition principle, the mechanical model and the failure depth criterion of the floor were established, respectively. The distribution and evolution of mining-induced stress and the plastic zone in surrounding rock during the mining process are obtained by FLAC3D. In addition, the changes in the P-wave wave velocity in the floor before and after mining were compared and studied by the acoustic wave test method. The range of floor damage depth is determined on the basis of the above research.

Jun 8, 2022

By Joel Bradley, Kot Unrug, Kyle Perry, Mark Klimek

"A West Kentucky mine operation in No. 11 seam, encountered floor heave, due to the localized increase of the thickness in the fireclay mine floor. Floor heave has overridden seals installed in two mined out panels. The third seal’s location was planned for isolating that area from the Mains. A plan of support has been developed to prevent repetition of the floor heave and related problems outby the seals. The applied ground control measures were successful. An attempt of a 3D numerical modeling was made, that it would match the observed behavior of the mine floor and could be used as a design tool in similar conditions. In the paper described are sequence of events, a mitigation ground control system applied, and the first stage of numerical modeling.IntroductionWest Kentucky coal mine operation in the No. 11 seam has approached an area where the fireclay floor thickness increases to about 5 ft. Delayed floor heave has been observed. In the first sealed area (Panel KK), floor heave has overridden the seals and has begun to progress outby. This could not be allowed at the new seal location PP described in this paper because such override would affect the mains. Previously numbers of standing support systems were used, but their effectiveness was not satisfactory as is illustrated in Figure 1, Figure 2, and Figure 3. Therefore, with sealing of the next area approaching, mine management was looking for a better solution that would eliminate the problem. In that stage, our team looked closely at the geology and strength of roof and floor, as well as the characteristics of ground failure around the seal at the first site. The technical literature has been searched as well Haramy et al. 1986 Hsiung and Peng 1987, Peng 2008, Santos & Bieniawski 1987. This led to the identification of factors responsible for the ground failure. It has been determined that increased fireclay thickness from typically less than 2 ft to about 5 ft, when compared to the previously mined parts of reserve, and the strong limestone strata just above the immediate roof composed of 2 ft of black shale, created conditions of failure. It appeared that, when pillars were punching into the mine floor, the strong roof did not break but was bending, exerting high pressure on outby pillars, causing rib failures and closure. This is a similar mechanism to a strong roof affecting longwall shields. The remedial action planned was additional support."

Jan 1, 2015

By Russell E. Clemons

Coarse-crystalline granite, quartz syenite, syenite, meladiorite, and anorthosite in the Florida Mountains, southeast of Deming, New Mexico, were originally mapped as Precambrian. They were remapped in 1971 and some of them described as Mesozoic intrusives. Several subsequent papers presented Precambrian and Ordovician ages. Zinc, lead, copper, silver, gold, manganese, fluorite, and barite mineralization in the Florida Mountains invite more extensive exploration. Clarification of ages of rocks and periods of alteration and mineralization are necessary for efficient exploration. Field observations combined with petrographic studies strongly suggest that all the coarse plutonic rocks are Precambrian and most were altered extensively by late Tertiary hydrothermal activity.

Jan 1, 1982

By Carl Henrich

In the planning and erection of smelting-works, especially of such as contain the modern large water-jacketed blast-furnaces, we are often confronted with an insufficiency in the watersupply. It may be impossible to find in the immediate neighborhood of the selected site a sufficient supply to furnish the jackets with cold water. Or there may be enough water for this purpose, but it may be highly charged with scale-forming minerals held in solution. Or, the main water-supply, if pumped from the workings of a mine, may carry iron- or copper-salts, or even some free acid in solution, all of these substances being derivable from the oxidation of sulphuret-ores in the mine. Moreover, such mine-waters sometimes contaminate the waters of the creeks, so that these become unavailable, and we have to fall back on an inadequate supply of pure water furnished by some spring or springs, entirely too small in

Jan 1, 1896

By Richard F. McFarlin

INTRODUCTION Phosphate, one of the three major elements essential for all living plants and animals, has been mined in Florida for over a hundred years. Comprising roughly 80% of the U.S. total and 25% of the world's supply, the bulk of the 35 to 40 million annual ton output is converted to chemical fertilizers. With the exception of one mine in north Florida near the Georgia state line, today's mining activities are centered in the middle of the peninsula just east/southeast of Tampa in Polk, Hillsborough and Hardee counties. These "bone valley" deposits extend into Manatee and DeSoto counties, but there is little active mining there as yet. Because strip mining is, perhaps, the ultimate environmental insult and because Florida has a proactive environmental community, it is not surprising that the mining of phosphate rock has become increasingly controversial. This paper describes how phosphate rock is currently mined, the environmental problems presented by mining and processing the rock, and some mitigating technologies being employed to answer such problems. THE PHOSPHATE DEPOSIT AND ITS EXTRACTION Florida's phosphate deposits containing the calcium phosphate mineral, carbonate-fluorapatite, are between ten and fifteen million years old. The typical "bone valley" matrix is 15 feet thick and lies under 20 to 30 feet of overburden.(Fig. 1) Both the sandy overburden and matrix are unconsolidated and can be removed with standard 45 to 65 cubic yard, walking electric draglines. After removing the overburden, which is windrowed nearby, the dragline operator casts the matrix into a "slurry" pit where it is broken up by high pressure water monitors. Pit pumps (with boosters where necessary) transport the matrix slurry through 16 to 20 inch pipelines to a washer where the three components of the matrix (sand, clay and apatite) are separated. The phosphates contained in central Florida matrix are approximately half pebble/half flotation feed, through the pebble ratio decreases as the industry mines southward. Again, the matrix is roughly equally divided among sand, clays and apatite. The phosphatic clays, 75% of which are less than one micron in size, leave the washer as a 3 to 5% colloidal suspension. The impoundment of these waste clays is one of the environmental challenges to be discussed later. The sand (silica) is separated from the similarly sized phosphate particles by a double float process (fatty acid followed by a reverse mine or cleaner float), and the sand tailings are then pumped to disposal or reclamation sites. The apatite flotation product is combined with the screened phosphate pebbles and stacked to dewater before shipping.

Jan 1, 1992

By P. G. Claridge, G. P. Holmes, M. A. Redfearn

"IntroductionThe purpose of this chapter is to describe current practices in operation and maintenance of flotation circuits in Canadian mineral processing plants. The chapter consists of five sections covering description of equipment, typical flow diagrams, operating practice, instrumentation and maintenance. The approach to this subject matter is intended to be practical in nature, hence no deeply technical treatment of flotation theory will be included.Flotation is an extremely common method of beneficiation of ores. Reasons are the relatively low cost of flotation compared to many other processes, the wide range of minerals to which flotation may be applied and the high efficiency of separation which can usually be achieved. The flotation process as we know it today has been developed within this century and it has had a major impact on the mining industry. While flotation is commonly considered to be important because it provides a relatively simple method of separating minerals in complex ores, the availability of flotation has also made a multitude of mineral deposits in Canada into economically viable mining operations because it allowed production of a concentrate of valuable minerals from the ore. These concentrates could then be transported from geographically remote locations to centraHzed plants for further processing, although the existence of the remote and perhaps small ore body alone would not have justified installation of metallurgical processing plants on site and the grade of ore would not have justified direct shipment of ore.Some of the more common minerals concentrated by flotation are sulphides of copper, nickel, cobalt, iron, zinc, molybdenum, lead and arsenic, as well as non-sulphides such as sodium chloride, potassium chloride, phosphates, silicates, chromite, fluorite, limestone and coal. Precious metals are also recovered by flotation, generally in association with another sulphide mineral."

Jan 1, 1989

By W. D. Guo, Y. M. Zhu, B. B. Luo

The main chemical constituents of waste cooking oil are higher fatty acid glycerides, which can be used to produce anionic fatty acids for most non-sulfide flotation. However, using the mixed fatty acids (MFA) produced by waste cooking oil as collectors directly, the flotation effect is usually not satisfactory, especially at lower temperature or room temperature. There are very rare systematic studies about the reason for poor flotation performance of waste cooking oil. This study aims to investigate the flotation and adsorption characteristic of different types of fatty acids in waste cooking oil to find out what kind of fatty acids results in the poor flotation performance. This will provide technical supports and theoretical guidance for the waste cooking oil application in the field of mineral processing. In this study, MFA were produced from the waste cooking oil, and then separated into saturated fatty acids (SFA) as well as unsaturated fatty acids (UFA), which possessing different flotation properties. The properties of the MFA, SFA and UFA were analyzed by iodine value, melting point measurement, Fourier transform infrared (FT-IR) spectroscopy and quartz micro-flotation tests. The results showed that UFA was composed of fatty acids containing group—(CH=CH—CH2)n—, having an iodine value of up to 162.90, a melting point as low as -17.3 ? and stronger low-temperature floatability. In contrast, the SFA was made up with saturated fatty acids and a few oleic acids, with an iodine value of 48.97 and a melting point of 38.8 ?. SFA had shown poor collectability and required a flotation temperature higher than 35 ?. The results of zeta potential measurements, solution chemistry calculation and FT-IR spectra revealed that both UFA and SFA can be adsorbed on the quartz surface activated by CaCl2 via the chemical and hydrogen bonding. The reason MFA having a poor flotation performance is the SFA has an extremely high melting point which affecting the dissolution of the dispersion.

Jan 1, 2018

By D. Lascelles, J. A. Finch, E. El-Ammouri

Flotation separation is expected to be related to the degree of dispersion of the pulp. For instance, highly aggregated systems may show reduced selectivity, reduced entrainment and increased flotation rate. In an attempt to test the impact of aggregation on flotation, we have taken advantage of the effect of Mg ions. Using combinations of Mg2+ and pH gave a wide variation in aggregation of several Cu-Zn ores (measured by settling rate) and corresponding flotation response was determined by batch tests. The trials were conducted on-site at Louvicourt and Agnico-Eagle. In a majority of cases a similar trend in aggregation and flotation selectivity (grade at given recovery) was observed. At Louvicourt, improved selectivity with increasing aggregation at pH 10.5 was found. At Agnico-Eagle, an analogous association between aggregation and selectivity was observed at pH 11.5. It is suggested that aggregation influences particle entrainment, the increased effective particle size reducing gangue recovery and hence improving selectivity.

Jan 1, 2004

By Willis Forsling, Prabhakar Swarna, Hanumantha Rao Kota

The solubility of wollastonite and its Hallimond flotation behavior as a function of dodecylamine concentration and pH are examined. The flotation response is characterized by adsorption and surface energy in the presence of amine. The methods of UV-Visible and FT-IR spectroscopy for adsorption and sessile-drop contact angle for surface energy estimation are employed. The results of wollastonite dissolution clearly showed its non uniform dissolution. The surfaces are depleted with calcium ions and became rich in silicon within 10 min of flotation time. Maximum flotation of wollastonite corresponds to a half monolayer coverage of amine, which is substantiated by the surface energy parameters. A good correlation between flotation, adsorption and surface energy as a function of amine concentration and pH was observed. The sudden increase in wollastonite flotation and amine adsorption at and above 5x10-5 M initial amine concentration is thought to be due to two-dimensional precipitation of amine on surface in accordance with the recent 2D-3D precipitation model of amine adsorption on silicate minerals.

Jan 1, 2003

By Yongjie Bu, Wei Sun, Zhiyong Gao, Yuehua Hu, Hongbiao Tao, Runqing Liu, Central South University

"The flotation behavior of O-isopropyl-N-ethyl thionocarbamate (IPETC) and pH for chalcopyrite and galena was studied through pure mineral test, adsorption quantity determination, solution chemistry calculation and Materials Studio simulation. The results show that the recovery differential value of chalcopyrite and galena is about 20% when pH of the pulp 9.5 and IPETC is 7×10-4 mol/L, the flotability differences of the two minerals is significant. There is competitive adsorption between OH? and IPETC on mineral surfaces, it lead to galena flotability is lower than chalcopyrite flotability. IPETC can remove the hydration layer on mineral surface and adsorb on active sites for collector adsorption, minerals have a better hydrophobicity.INTRODUCTIONCopper and lead are two of the most widely used metals in industrial and living, their applications include building construction, various metal alloys, heat and electricity, machine manufacturing (Zhang et al., 2014). Chalcopyrite and galena are the major source of copper and lead, normally they associated with each other. With the growing use of these resources, high grade and dissemination large particle sizes minerals are less and less, the use of low grade and complex dissemination minerals have to be paid more attention (Chen, Ye, & Li, 2010; Liu, Sun, Hu, & Wang, 2009). As the special properties and complex composition of copper-lead sulfide ore, flotation separation of chalcopyrite from galena effective is a research emphasis and difficulty point in mineral processing (Bruckard, Sparrow, & Woodcock, 2011).In the separation process of chalcopyrite and galena, it is rather important to choose effective collector (Huang, Wang, & Liu, 2014). Enlarging and using the two mineral flotability will be a good basis and start in flotation (Reyes-Bozo et al., 2014). Qin et al. (2013) made a great deal of research on flotation separation of copper/lead concentrate, collector O-isopropyl-N-ethyl thionocarbamate (IPETC), butyl xanthate (BX) and ammonium dibutyl dithiophosphate (ADTP) were investigated, BX and ADTP floated both chalcopyrite and galena well, specific adsorption appeared in the surface of mineral, the problem was the collectors were not selective enough, however IPETC showed better selective."

Jan 1, 2016

By G J JAMESON

The flotation cell has undergone a number of changes since the process was first introduced in Broken Hill in the early years of this century. The development of the mechanical flotation cell is reviewed, followed by a discussion of more recent developments such as the flotation column, the air-sparged hydrocyclone, the Wemco-Leeds cell, the Bahr and Deister columns and the Jameson cell.

Jan 1, 1992

By Saeed Farrokhpay

It is known that the grinding condition has a major effect on the beneficiation characteristics of the minerals in subsequent processing, in particular, flotation. In the flotation process, particles surface and their condition can significantly influence collector adsorption and flotation performance. For example, particle shape and its surface roughness occurred during grinding may influence flotation characteristics of a specific ore. In fact, adsorption of different cationic and anionic species on mineral surfaces can be varied depending on the selected comminution procedure. The flotation performance of sulphide minerals can be detrimentally affected by the surface oxidation. The amount of surface oxidation may reduce the hydrophobicity of the mineral and makes adsorption of collectors less selective. Improved liberation may generally result in improved flotation recovery. However, this may result in finer grinding and slimes, and consequently, reduce the overall flotation recovery. This paper discusses the effect of wet and dry grinding on copper flotation of a complex Cu-Pb-Zn ore. Industrially, wet grinding is preferred due to its higher energy efficiency and owing to downstream processing requirements. In this study, series of flotation tests were conducted,and surface analysis (XPS and ToFSIMS) were performed after wet or dry grinding at two different P80 values. Mineralogical study was also conducted to investigate the liberation of valuable minerals after grinding. A higher copper flotation recovery was found for wet grinding. However, the copper recovery was increased by further grinding in both conditions (wet and dry). The results showed a higher collector adsorption on copper mineral surfaces after wet grinding. The surface analysis also revealed that the ore is slightly more oxidized after dry grinding probably due to higher temperature during dry grinding.

Sep 1, 2012

By M. S. Celik, H. Du, J. D. Miller, F. Cheng, O. Ozdemir

"In this paper, recent progress with respect to the flotation chemistry of soluble salt minerals is reviewed, and some of the more relevant issues including the hydration states of ions, the interfacial phenomena of salt surfaces and the flotation behavior of selected soluble salts are discussed. Due to the high solubility, the flotation of most soluble salts has to be carried out in their saturated brines. Anecdotal evidence has suggested that the hydration states of the ions have significant influence on the physicochemical properties of the solutions, the surface charge and wetting characteristics of the minerals, the collector adsorption states and, further, the flotation behavior of the soluble salts. In this regard, reviewing past research findings, efforts are made to establish a correlation between the ion hydration states with the flotation behavior of the soluble salts. Further, advances in understanding the significance of colloid adsorption involved in the soluble salt flotation process are addressed, and future research efforts to understand the soluble salt flotation chemistry are suggested.IntroductionSoluble salt minerals are essential raw materials for the production of a variety of commodities, fertilizers, potassium hydroxide, soda ash, magnesium compounds and other chemicals. These soluble mineral resources can be processed using flotation technology and, currently, more than 80% percent of the world’s potash is produced by the selective flotation of KCl crystals (sylvite) from other salt crystals, predominately NaCl (halite) and other more complex salts (Searls, 1990). Despite the successful application of flotation technology in the potash industry, the mechanisms for collector adsorption on soluble salts have not yet been fully understood and, therefore, have been of considerable interest to flotation researchers for many decades."

Jan 1, 2015

By P Wigley

New methods of analysing and modelling flotation circuits have been developed as part of the AMIRA P9 mineral processing research project. A study using these techniques was conducted on the Olympic Dam copper flotation circuit to provide the following outcomes: an estimate of the flotation cell hydrodynamic properties and froth performance characteristics, and identification of potential areas for improvement; an estimate of the feed floatability parameters for basic model development; and identification of potential flotation circuit improvement opportunities. A flotation circuit model of the Olympic Dam copper concentrator was developed using the data collected from mass balanced site surveys, along with hydrodynamic data, froth performance data and numerous laboratory batch flotation tests. The simulator that has been developed from the model has the ability to estimate the influence of selected changes (such as circuit changes) on flotation circuit performance. Several stream destination simulations were conducted to provide guidance for further testwork and possible circuit improvements. The results from these simulations are presented.

Jan 1, 2003

By Dan Alexander, Ivan Crnkovic, Sarah Schwarz

"Several plant studies have been conducted at the Zinifex Century Mine over the past 5 years. For each of the plant studies, surveys of the zinc primary circuit were conducted, characterisation measurements for each operating cell taken, and the floatability components of the ore mapped to develop a model of the circuit. The floatability components and machine parameters were then used to simulate changes in circuit configuration and operating conditions, enabling further potential improvements in circuit performance to be identified.This paper reviews the current flotation practice at the mine, as well as various circuit changes and developments implemented by site. The application of the methodology and the evolution of the standard procedure are also discussed.INTRODUCTIONBase metals were first discovered in the Lawn Hill region of Queensland’s North West in 1869 and the first mining lease in this area was pegged in 1887 over what is now known as the Silver King vein deposit. The area encompassing these veins, which includes the Century deposit, was proclaimed the Burketown Mining Field in 1899. Exploration titles were granted to CRA in 1987, precisely 100 years after the initial discovery at Silver King, hence the name ‘Century’.Century was commissioned by Pasminco in late 1999, with the mine becoming fully operational on 1 March 2000 and the official opening taking place in April. Pasminco had bought the Century and Dugald River deposits from CRA in 1997 for A$345 million, and invested some A$710 million in bringing Century into production. Today, Century is the world’s second-largest zinc mine in terms of its output, having reached full capacity in 2003.The Zinifex Century Limited (“ZCL”) lead-zinc-silver deposit is located approximately 250 kms north-north west of Mt Isa in north-western Queensland. The deposit is a large flat-lying ore body covering an area of some 1.2 by 1.4 km, the 45 m-thick stratabound sulphide orebody is hosted within an 850 m-thick sequence of Proterozoic siltstone, shales and sandstone, amenable to open-cut mining methods. The mine has ramped up to full production delivering five and a half million tonnes of ore per annum, yielding approximately 900,000 tonnes of zinc concentrate and 90,000 tonnes of lead concentrate. Mine life is expected to be about 8 years"

Jan 1, 2008

By A Nugraha, H Thanasekaran, K Tatetdagat

The Kanowna Belle gold mine is located in the Eastern Goldfields of Western Australia, approximately 18 km north-east of Kalgoorlie. The processing plant is designed to process 2 Mt/y and has the capability to treat both refractory and free milling ore from the Kanowna Belle and Kundana mining operations.The Kanowna Belle ore is refractory with the gold mineralisation occurring mostly as fine-grained inclusions in pyrite or as very fine-grained gold located in pyritic arsenic rich growth zones. The Kanowna Belle refractory process includes flotation, roasting of the flotation concentrate, and calcine leaching to extract the gold from the ore.Mineralogical analysis of feed and tailings streams from the flotation circuit have shown that the gold bearing minerals are well liberated and confirmed they are mainly associated with pyrite. Nearly 40% of the flotation circuit losses are in the -38 µm size fraction. To improve the flotation circuit recovery, the fine particle gold recovery was targeted. A Cavitation Tube column was selected for the site-based pilot test work program. This paper presents data generated from the on-site test work, and the benefits of the Cavitation Tube column to improve fine particle flotation.CITATION:Nugraha, A, Tatetdagat, K and Thanasekaran, H, 2018. Flotation circuit efficiency improvement at Northern Star Resources Limited’s Kanowna Belle gold mine, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 403–412 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By Patrick Pelletier, Pierre-Alexandre Bossé, Julie Fournier, Gianni Bartolacci, Jayson Tessier, Ahmed Bouajila, Carl Duchesne

"This paper summarizes research into the study of the control of flotation processes based on froth images. The use of numerical image analysis techniques for the extraction of significant patterns (froth structure and colour) from industrial flotation froths is discussed.First, the froth was analysed by the use of the Multivariate Image Analysis (MIA) method to extract the spectral variation contained in a RBG image. The Partial Least Squares (PLS) was applied to develop the empirical model for the prediction of froth grade. The results of this application are illustrated using one industrial case study.Second, the froth was also analysed by Gray Level Co-occurrence Matrix (GLCM) and Wavelet Transform Analysis (WTA) to extract features related more to morphological aspects. Since there is useful information hidden in froth texture, these methods are used as texture descriptor to classify different types of froths.Third, a control strategy based on a froth structure indicator was developed and implemented on an industrial zinc flotation circuit. The feedback controller uses a reagent flow-rate in order to maintain the froth structure at its set point. Process improvements obtained with the implemented control strategy are highlighted.Finally, the feasibility to implement a hybrid control strategy consisting in a froth structure supervision controller based on the froth concentrate grade estimated by MIA and recovery inferred by image analysis is discussed.INTRODUCTIONThe development of control strategies to achieve satisfactory control performance has always been a great challenge for engineers and the need for improved process diagnosis, control and optimization has become more and more evident for the mineral processing industry in the last decades. That is why new process variables need to be measured particularly in highly multivariable processes such as flotation. This industrial process is subject to a wide variety of disturbances mainly generated by frequent and sometimes abrupt changes in physical and/or chemical ore characteristics and also, due to some irregularities in manual process operating procedures. A flotation circuit scheme is always a complex network of more than two dozens slurry streams. Information about those streams (% solid, metal content analysis and flow rates) is important for process diagnosis performance evaluation and control. Also, because of the grade decrease and increasing complexity of the new processed ores, more instrumentation outputs and more powerful and significant pr"

Jan 1, 2005