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By J. Keith Seidler, David R. Lentz, Douglas C. Hall, Nicholas Susak

Abstract - The Ta-Nb-Zr-REE-rich McKeel Lake alkali granite pegmatite-aplite dike swarm is hosted within the late Silurian multiphase alkali granite intrusion (Welsford) near Browns Flats in southwestern New Brunswick. A steep easterly dipping series of pegmatite-aplite dikes trending 170º can be traced 150 m along strike; they are up to 40 cm wide, closely spaced (10-20 cm apart), and interconnected by narrow branching dikelets that generally trend perpendicular to the overall strike direction. The Welsford intrusion has mantle A-type affinities characterized by enrichment of Zr, Ta, Nb, Th, and rare earth elements (REE). Two separate sets of dikes have been identified: (1) an unmineralized fine-grained porphyry, which occurs at depth and seems to be the youngest intrusive phase; and (2) a mineralized pegmatite-aplite dike swarm (419 ± 20 Ma) that crops out at surface. The mineralized pegmatite-aplite dikes likely represent a late magmatic, highly fractionated phase of the Welsford intrusion. XRF and INAA data indicate that the Welsford intrusions and related pegmatite-aplite dikes show elevated levels of Ta (74-220 ppm), Nb (750-3,040 ppm), Zr (1,450-36,000 ppm), Y (540-3,070 ppm), Th (170-870 ppm), U (60-250 ppm), Ce (430-1,950 ppm) and Yb (110-290 ppm). Electron microprobe analysis of two samples identified Ta-Nb- and REE-rich phases: euxenite, fergusonite, aeschynite, (Y)-aeschynite, and a REE carbonate.

Jan 1, 2005

By Gérald Riverin, Bernard Boily, Daniel Bernard

"The Donalda gold deposit is located in the southern part of the Noranda camp, approximately 2 /em east of the Horne deposit. Combined past production and current reserves total over 1.5 Mt grading 6.9 grams of gold per tonne.The deposit consists of two main veins which are both narrow but persistent structures. The No 1 Vein, hosting about 80% of the gold ore, consists of an EW-striking banded quartz vein dipping on average 25° to the south. Although variable in thickness, it averages lessthan1 metre. TheNo2 Vein, located 300 m below the No 1 Vein, is similar to it except that it dips 50° south. Gold occurs mostly as fine native gold disseminated in quartz, with 2-3% pyrite and trace amounts of various sulphides and tellurides. The wall rocks are only weakly altered and mineralized with pyrite, hematite and sericite.Structurally, the Donalda deposit is centered on the Horne Creek fault (HCF) where the HCF is intersected by the ENE-trending DonaldaandCentralfaults.NorthoftheHCF,theNo1Veinishosted by the Quemont Rhyolite, whereas south of the HCF the vein is hosted by magnetic basalts and diorites of the Wilco Andesite Formation. The No 1 Vein extends across the HCF with only minor displacement, whereas the No 2 Vein has not yet been traced south of the HCF.A preliminary structural analysis of the mine shows that the HCF, which strikes 275° and dips 70° north in the mine area, has a reverse movement a lid that the flat dipping No 1 Vein is a tension vein. Both probably developed in response to the same stress conditions. Although the absolute age of the Donalda veins is not known, structural relationships indicate that they formed during the latest movements of the HCF, but prior to the intrusion of the Proterozoic D' Eldona Diabase. The occurrence along the HCF of gold-rich synvolcanic massive sulphides and much younger vein-type gold deposits (such as Donalda) indicates that the HCF was a very long-lived, deep-seated (?)structure which has controlled the circulation of gold-rich fluids over a long period of time."

Jan 1, 1990

By Michael Zurowski

This paper traces the history of International Mogul's assessment program on the Lake Ainslie barite-fluorite deposits of Cape Breton Island. The geology of the area is outlined, and the main vein systems described. The geophysical and geochemical exploration techniques employed are explained, the metallurgy of the ore is covered, and the market prices and economics of operation are described.

Jan 1, 1972

By C. M. Campbell

IN 1934 Newfoundland, after extravagant operation based on exaggerated ideas of what she had to work with, became bankrupt, ceased to be a self-governing Dominion, and passed into the hands of a Commission. Since the days of Dawson, Canadians have been taught that no country in the world is as rich as their own. This idea has become a religion; contrary views are heresy, and are suppressed even by technical organizations and government departments. Following the alleged habit of the ostrich, we have buried our heads in the sand and have refused to face the facts. This policy of "to have today and to hell with tomorrow" is now bearing fruit. After forty years of operation on the basis of unlimited natural wealth, with resulting over-expansion, wholesale depletion of capital assets, and huge borrowings, we are, now that our wealth has been shown to be very limited, face to face with the status of Newfoundland. Already, in this Province, commission government of bankrupt municipalities is not uncommon. The ostrich is referred to as the most foolish bird in the world. That is not the case-no ostrich ever hid his head in the sand. In the clear air of his home on the South African veldt, an area characterized by low bushes, he is a conspicuous object. When danger approaches, he lowers his head; matches his background, the bushes; and danger passes him by. This leaves the Canadian, with his head still in the sand, to fill the r61e cast for the ostrich. Fortunately, a few Canadians never did get their heads covered; others are getting them out far enough to see what is going on. Their comments are very much to the point. "Nowhere in the world," says Mr. Meighen, "has more harm been done to any country by an exaggeration of its resources and potentialities than has been done in Canada'.

Jan 1, 1941

By Judith S. Chan

With the increasing awareness of the need for the reduction of carbon emissions globally, geothermal energy, which offers a potential for cleaner energy generation, is one potential new source. In Alberta, these geothermal resources are likely to be found in the sedimentary basin, or in the deeper crystalline basement rocks. Alberta exhibits a very low geothermal gradient compared to other existing geothermal fields located in areas of volcanic and tectonic activity. To mitigate this effect, the focus in Alberta will involve the development of engineered geothermal systems (EGS) in the target resource. The first goal for EGS research and development is to develop a detailed geological-geophysical characterization of selected sites to delineate potential geothermal reservoirs in Northern Alberta. One of the selected sites is in the Fort McMurray area. The deepest well drilled in the oilsands areas of Northern Alberta is located just west of Fort McMurray. It has a depth of 2363 m and as such can provide details on the physical properties of the rocks, the state of stress, and the existence of fracture porosity toward geothermal investigations. To date, we have acquired temperature logs to study the change in geothermal gradient with depth, and a series of petrophysical logs to study the finer scale structure of the rock formations with vertical resolutions in the range of 0.05 cm to 80 cm. Our aim is to identify geological features such as zones of fractures in the basin and/or basement that could provide an indication of enhanced fluid flow potential ? a necessary component for any geothermal systems to be viable. Zero offset and walkaway vertical seismic profiles (VSP) were also conducted to measure the seismic responses at the borehole. VSP data can be used to delineate the structural and stratigraphic features surrounding the borehole that could not be resolved from surface seismic reflection data that are also available near the borehole. The full integration of well logs, VSP data and surface seismic reflection data are expected to provide a detailed characterization of the sedimentary basin and crystalline basement rocks of the Canadian Shield in Northeastern Alberta and will assist in future planning for drilling.

Jun 1, 2012

By Imane Benhamed, Jaouher Diouani, Laurent Cassayre, Florent Bourgeois, Carine Julcour-Lebigue, Université de Carthage

The attrition-leaching process aims at improving leaching performance when formation of passivation layers at the surface of leached particles is a severe limiting factor, as discussed recently by Julcour and coworkers (Julcour et al., 2015). This paper proposes a geochemistry-based modelling scheme for deriving the window of possible operating conditions for the attrition-leaching process to match the properties of the processed ore. The rationale is that the attrition-leaching process maintains the surface of reacting particles in an unpassivated state by continuous mechanical removal of surface leach layers, so that the process reactions can be modelled from thermodynamic equilibria throughout the duration of the process. The strength of the proposed modelling approach is that it bridges the gap between the properties of the ore and the process operating conditions. The present paper exemplifies the proposed process modelling route for derivation of the attrition-leaching process operating conditions in the context of the leaching of silicate ores, matching model predictions against controlled laboratory experiments. It is shown how thermodynamic modelling, when used in conjunction with a solid knowledge of the phases present in the system, can assist with deciding upon suitable process operating conditions. As an example, this firstprinciple modelling approach predicted that steel grinding medium would be converted into siderite (FeCO3) under a wide range of operating conditions, which led to questioning this initial choice of grinding medium for the attrition-leaching process under mineral carbonation conditions. It is emphasised that the same approach could be applied to ores of greater economic significance.

Jan 1, 2016

By D. R. Lentz, S. H. Mcclenaghan, J. A. Walker

"Abstract - The Orvan Brook deposit is one of several (Zn+Pb>>Cu)-rich sulfide deposits hosted by the Spruce Lake Formation (California Lake Group) in the northwestern part of the Bathurst Mining Camp. This parautochthonous deposit is hosted by a narrow band of highly deformed, locally graphitic shale that appears to conformably overlie felsic volcanic rocks of the Spruce Lake Formation, and is in tectonic contact with overlying mafic volcanic and related sedimentary rocks of the Canoe Landing Lake Formation. The Spruce Lake Formation is dominated by felsic volcanic rocks and subordinate fine-grained sedimentary rocks, and mafic volcanic rocks (Canoe Landing Lake member). The felsic volcanic rocks can be divided into aphyric and feldspar-phyric rock types. The feldspar-phyric rocks and a few of the aphyric varieties have a Zr/TiO2 ratio of 0.06, and fall into the California Lake Group field on a Y/TiO2 versus Zr/TiO2 diagram. In contrast, the aphyric felsic volcanic rocks have Zr/TiO2 ˜ 0.09 and are marked by high Zr and Th, which is consistent with highly fractionated felsic magma of Spruce Lake affinity. Major and trace element analyses of host rocks suggest that weak to moderate hydrothermal alteration developed on the south side (stratigraphic footwall) of the deposit, which is consistent with a north-younging succession. The sulfide lens strikes east-west for approximately 2.3 km, extends down-dip for at least 500 m locally, and has an average thickness of between 0.75 and 1 m, but is locally up to 5.5 m thick. The contacts of the massive sulfide lens with its host rocks are invariably sharp. Host rocks show evidence of intense ductile deformation as well as later brittle deformation. Compositional layering and sulfide breccia textures in the sulfide body are interpreted to result from deformation or tectonic enhancement of original primary layering. The deposit contains an estimated resource of 2.69 Mt grading 1.73% Pb, 5.95% Zn, 0.37% Cu, 72 g/t Ag, and 0.9 g/t Au. Similarities in bulk d34S between the Orvan Brook (+8.6‰) and the nearby Cu-rich McMaster deposit (+8.2‰) suggest a common depositional setting."

Jan 1, 2006

By A. LA. Salama, D. B. Hyma

"The Western Research Centre (WRC) of CANMET located in Devon, Alberta, is a modern research facility offering services ranging from fundamental research to pilot plant investigations. Recently, a 0. 76 metre diameter by 7.9 metre high Flotaire column flotation cell was installed as a demonstration unit for Canadian coal producers. Because the column cell is intended to be used for research, development and demonstration, WRC recognized that additional sensing equipment and improved process control would be required to generate good data for subsequent column scale-up and engineering design.A low cost, personal computer based control system was, therefore, designed and installed. This paper describes the stepwise procedure in developing the control strategies, selection of system software and hardware, and installation and configuration of the system.Preliminary performance data on a western Canadian coal sample are also presented. Future testwork is planned on additional coal samples to expand upon existing database."

Jan 1, 1993

By G. H. Agnew

When water floods are initiated after gas-oil ratios have increased, the transition period from the start of injection until" the gas-oil ratios are returned to the solution gas-oil ratio may be important for either economic or technical reasons. The transition period is longest, and consequently most critical in water floods where injection is equal to withdrawals. This paper describes a theoretical basis for predicting the behavior of such a system and outlines a procedure for making the necessary calculations. The calculation procedure is illustrated for two actual cases: a line drive water flood and a five spot water flood. In each case there is a reasonable similarity between the actual and calculated performance.

Jan 1, 1960

By Hani S. Mitri

Overhand cut-and-fill mining of narrow vein orebodies inevitably leads to the creation of horizontal pillars. As the thickness of the overlying crown pillar diminishes, stresses build up in the pillar. More often than not, this situation causes an increased level of seismicity and possible pillar burst. One well-known strategy to reduce the hazard of crown and sill pillar burst in cut-and-fill vein mining is that of destress blasting. The paper first reviews the methods used for the monitoring and assessment of potential pillar burst in narrow vein cut-and-fill mining. The influence of horizontal stress, mine depth and pillar thickness on stress build-up in the crown pillar is examined through a characteristic narrow vein numerical model. The paper then presents, with reference to three mine case studies, the benefits of destress blasting and the factors affecting its success as a ground control technique.

Oct 1, 2001

By E. Faria

"The Santa Rita mine is located in north eastern part of Bahia in Brazil and is owned and operated by Mirabela Mineração do Brasil Ltda. Typical SABC circuit was designed as the preferred option for the 4.0 mtpa (500tph) to produce a P80 of 125um for flotation. Although the SAG was originally designed to operate with conventional radial pulp lifters, later it was fitted with Outotec’s Turbo Pulp Lifters – TPL (Latchireddi, 2005). The milling circuit commenced commissioning on the 24th of October 2009 and the milling circuit achieved the nameplate capacity within days. with small and relatively simple measures to rectify. Since commissioning, the SAG mill has been working in fully autogenous grinding (FAG) mode with no balls (in contrast to the estimated 10% ball charge) and has been consistently treated up to 650tph.This paper examines the comminution design process, the operating philosophies, start-up experiences, post commissioning optimization and future development works. An evaluation of mill performance relative to the design criteria for the project life to date is also included."

Jan 1, 2012

By B. N. Church, J. J. Barakso, A. F. Bowman

"An evaluation of mineralization in the Goosly- Owen Lake area of central British Columbia is the result of a comprehensive geochemical study of rock samples obtained from a regional geological survey. The dispersion of metals in country rocks about a line of Tertiary intrusions suggests that these igneous bodies may be genetically related to known sulphide replacements, disseminations and vein deposits. The geochemical investigation is based on the determination of 12 elements from samples gathered from more than 800 scattered field stations. To assist processing and interpretation, the data are subjected to a variety of statistical procedures, including correlation of the elements, factor analysis, clustm• analysis and computer contouring of the elements. Some practical applications of rock geochemistry in regional exploration are indicated."

Jan 1, 1976

By C. O. Aksoy, P. M. Ozfirat, M. K. Ozfirat, C. Tatar, C. Pamukcu

"Temporal and other factors contributing to the occurrence of occupational accidents at an underground coal mine in Turkey between 1992 and 2000 have been analyzed. The time period of the study spanned the transition from hand-worked mining methods (1992 to 1996) to hand-worked mining methods and mechanized mining methods (1997 to 2000).The mine selected for the study employed an average of 5,835 men per year on three separate eight-hour production shifts for 302 d/y (Sundays are not worked, and there are 11 holiday days per year). Production on an annual basis averaged 190,000 tons per year between 1992 and 1996, and 300,000 tons per year between 1997 and 2000.The purpose of the study was to determine which, if any, of the factors studied contributed to the occurrence of accidents so that the mine could take the necessary steps to reduce the risk to the workforce. Regression analysis was used to determine the strength of the relationship between each factor studied and the number of occupational accidents.The strongest relationships observed were between the age of the employee, the day of the week, and the total yearly labour."

Jan 1, 2006

By George C. Coupland

"THE PRELIMINARY EVALUATION of the orebodies was computerized for tonnages and grades on a 20- by 20-ft grid. The evaluation was based on drill-core intersections over 40-ft vertical projections coinciding with the proposed bench intervals, taking the deviations of the drill holes into account. The computer print-outs gave an ore distribution and evaluation bench by bench and indicated the areas of varying mineralization. The two orebodies have a combined length of 2,200 ft. and a maximum width of 600 ft. They strike almost due north, dip about 85 degrees east and rake to the north. The computer print-outs were used to design an open pit with an over-all waste to ore ratio of 2.58:1. At the outset, the waste to ore ratio was 4:1. The pit is tear-drop shaped, with the narrow end to the south, and at the surface is 2,600 ft long by 1,800 ft wide. Ramps are 100 ft wide, with a 10% grade. The south ramp is left-handed, starts at the southeast and will continue to the bottom of the pit. A second ramp on the west and north walls runs from surface to join the south ramp at 7 bench. This ramp will handle the total pit production when part of the south ramp, from 4 bench to surface, is lost due to the underground operation. Over-all wall slopes are 53 degrees, and are laid out to avoid prominent protuberances which could relax and become unstable and potentially dangerous (Fig. 1) ."

Jan 1, 1974

Phelps Dodge has recently operated a commercial scale, super fine grinding circuit of copper concentrates for use in a medium-temperature pressure leaching process. Two 355 kW vertical stirred mills were installed in series, targeting a grind of 80% passing 7.5 µm and 98% passing 15 µm as outlined in Phelps Dodge's concentrate leaching patent portfolio. This paper details the operation and results of the test program at Bag dad, as well as some of the operating challenges encountered.

Jan 1, 2007

By W. J. Wolfe

"Quartz Hill is a large, low- to moderate-grade quartz vein stockwork porphyry molybdenum deposit, discovered in 1974 during a regional stream sediment geochemical reconnaissance survey of southeast Alaska conducted by United States Borax and Chemical Corporation. Mineralization is localized in the upper parts of an Upper Oligocene (30 Ma) composite quartz monzonite stock which is emplaced discordantly into older Cretaceous to Early Tertiary terrain of the Coast Range igneous metamorphic complex of the northwest North American Cordillera. Subsequent fault-controlled, complex multi-stage intrusion, concentrated in the core of the Quartz Hill stock, produced successive pulses of hydrothermal alteration and molybdenum mineralization at about 27 Ma. Overall, the deposit is tabular and flat-lying and well suited to open pit mining. The 0.05% MoS2 grade limit covers an area of approximately 1500 m by 2750 m and extends to a maximum depth of 520 m below surface. Details of grade distribution show two separate lobes of higher grade material within the larger low-grade deposit.A ten year program of exploration drilling, underground development, sampling and metallurgical testwork led to a 1983 feasibility study based on a resource of 1600 million tonnes grading 0.127% MoS2 at a 0.08% MoS2 cutoff The large size of the deposit and its homogeneous grade distribution, typically showing gradual outward decrease of grade, makes in pit grade selection practical at several cutoff levels. Cominco Ltd. now reports a Probable Resource of 210 million tonnes averaging 0.22% MoS2 with a further Possible Resource of 1100 million tonnes averaging 0.12% MoS:z. At low molybdenum metal prices which have persisted for 10 years since the molybdenum price spike of the late 1970s and early 1980s, the Quartz Hill deposit is sub-economic."

Jan 1, 1995

By C. T. Harper, B. J. Fryer, R. P. Taylor

"IntroductionThe Maurice Bay deposit is one of a number of uranium deposits that have been found in recent years in the Athabasca Basin of northern Saskatchewan (Tremblay, 1982). This deposit, along with the others, belongs to the unconformity type deposits (Beck, 1977). They are, for the most part, polymetallic, being characterized by a suite of metals which include U, Ni, Co, Cu, Pb, Zn, Mn, V, Ag, Au, Pt-group elements, S, As, Bi, Se, Te, and Mo, some of which, besides U, are present in economic concentrations (Amok, 1974; Ruzicka, 1975; Tapaninen, 1976; Hoeve and Sibbald, 1978; Dahlkamp, 1978). The Maurice Bay deposit was known to be a small low grade deposit in which the ore was essentially monomineralic, consisting mainly of pitchblende (Harper, 1978). However, the occurrence of trace amounts of some of the elements common in the larger polymetallic ore bodies (e.g. Key Lake, Cluff Lake D) was anticipated. Thus a lithogeochemical sampling project was undertaken in 1979 across part of the Maurice Bay deposit (Harper, 1979). Major oxides (SiO2, Al2O3, FeO, Fe2O, MgO, CaO, K2O, Na2O, MnO, P2O5, and TiO2) and a group of the most common trace metals (U, Ni, Co, Cu, Pb, As, Au, V, and Se) were analyzed to determine whether any elemental patterns (halos or depletions) could be detected which would reduce the number of pathfinder elements needed for exploration purposes. In addition to the above metals, Th was also checked because some conglomerate strata in the Maurice Bay area are known to be thorium-enriched (Harper, 1978). Only the trace metal distributions will be discussed in detail in this report.General GeologyThe Maurice Bay area is underlain by three major groups of rocks, the White Lake metamorphic complex, an unnamed granodiorite complex, and the Athabasca Group, described previously (Fig. 1; Harper, 1979). Table 1 summarizes the stratigraphic features as deduced by geological mapping and the examination of drill cores."

Jan 1, 1986

By F. T. Manns, G. Harper

"The Swayze gold mine is an Archean vein deposit in northern Ontario. The veins are superimposed on a conjugate joint system and are contained within an anastomosing alteration envelope in a metadiorite body. Reserves were estimated on the basis of fire assays of channel samples and car load samples from underground mine openings, surface and underground diamond drilling and surface trenching. A semi-variogram constructed from channel samples along one of the drifts yielded a horizontal, regionalized influence of approximately 9.0 m. Common industry practice has been to use 6.1 m for similar deposits in Ontario. Proven ore was defined from underground openings. The maximum extrapolation distance for proven ore along strike and dip from a data point is taken to be 6.1 m. Probable ore is extrapolated 7.6 m from a data point in a mine opening or from a drill intersection. Possible mineralization is based on geological continuity one-half the distance to a neighbouring data point.The mineral inventory estimate of 1.45 million tonnes at a grade of4.8 g Au/tonne gives an excellent outline of the geology of the deposit. The deposit contains 313 000 tonnes of ore reservesat a fully diluted grade of6.9 g Au/tonne. These figures include dilution for several reasons: (I) a 2.1 m mining width is used rather than the more typical 1.5 m width to allow for over break because of the shallow dip of some vein zones; (2) over break is allowed for adjacent to major unmineralized dykes; and (3) grams of gold are deleted from estimates to allow for the mining of unavoidable minor dykes.A personal computer with off-the-shelf software was used to compile 712 geologically defined ore blocks and sort them into a number of revealing categories. The computer was used to perform grade sensitivity tests, as well as to evaluate depth potential. Hopefully, the reiterative aspect of the method has randomized the errors and helped to cancel their effects."

Jan 1, 1987

By F. Habashi

"A short account will be presented on the extraction of rare earths from monazite sand, bastnasite ore, and phosphate rock of igneous origin. This includes mineral beneficiation, leaching methods, fractional crystallization [of historical interest], ion exchange, solvent extraction, precipitation from solution, and reduction to metals. INTRODUCTIONOriginally, the term rare earths was only used for the oxides, R2O3, which are similar to one other in their chemical and physical properties and are therefore difficult to separate. Within the rare earth group, the elements scandium, yttrium, and lanthanum differ in their atomic structure from the elements cerium to lutetium (the lanthanides, Ln). Scandium occupies a special position with respect to this classification and its other properties, and therefore does not belong to either of these groups. The rare earth elements always occur in nature in association with each other. The isolation of groups of rare earth elements or of individual elements requires costly separation and fractionation processes owing to the great similarity of the chemical and physical properties of their compounds, which explains why the history of their discovery has extended over such a long period.The word “rare”, when used to describe this group of elements, originates from the fact it was thought that these elements could only be isolated from very rare minerals. Considering their abundance in the Earth’s crust, the term rare is now inappropriate. These elements are lithophilic and are therefore concentrated in oxidic compounds such as carbonates, silicates, titano-tantalo-niobates, and phosphates.The abundance of the rare earth elements taken together is quite considerable. Cerium, the most common rare earth, is more abundant than cobalt. Yttrium is more abundant than lead, whereas Lu and Tm are as abundant as Sb, Hg, Bi, and Ag. For all practical purposes promethium does not occur in nature. It forms only in nuclear reactors."

Jan 1, 2012

By Gonzalo Díaz, Diego Mesa, Willy Kracht

"It is well known that frothers affect the amount of water that is transferred to the froth, which has an effect on both the froth stability and the water recovery. On the other hand, since non-selective recovery by entrainment is directly related to water recovery, it can be said that frothers have an indirect effect on flotation selectivity. Recent research on this subject has shown that the non-selective recovery by entrainment, which is characterized by the entrainment factor, is frother dependent. In other words, the entrainment factor is not unique, but depends on frother type.Having different entrainment factors implies that for the same water recovery, the amount of undesired particles reporting to the concentrate may vary if one changes the frother type, which suggests, as a possible explanation, that it is not only the amount of water in the froth what is affected by frother type, but also the froth structure.The purpose of the current work is to study the effect of frother type on foam structure (two phase froth). A quasi-2D cell operated with a slot sparger was used to study the foam structure in the presence of three different frothers: Methyl Isobutyl Carbinol (MIBC), OrePrep®549, and Octanol at the same gas flow rate and reagent dosage. The foam structure was studied using image analysis, and an algorithm based on textural analysis was developed to classify the foams. The results show that it is possible to classify foams according to the frother used, which proves that frothers have an effect on the foam structure.INTRODUCTIONFrothers are usually dosed paying attention to froth stability, condition that is commonly estimated by sight, according to the operator's criteria and experience. This happens because there is not an established procedure or technique for frother characterization, generating qualitative descriptions such as “powerful” or “selective” frothers, which lack of scientific thoroughness and remain under subjective factors. Nevertheless, several works have been done in this line of research. Moyo et al. (2007) classified frothers based on their water-carrying capacity, proving that this characteristic is related with gas holdup and frother type. Previously, Trahar (1981) had related water recovery and gangue particles recovery, defining the entrainment value (ENT). Nowadays it is known that entrainment affects both hydrophilic and hydrophobic because it is not a selective process. In the last decade some studies (for example the one of Konopacka and Drzymala (2010)) delved into different entrainment behaviours dependent mainly on the flotation type (batch or continuous, agitated or columnar, etc.), but there were no studies on the effect of frother type regarding entrainment, since Rahal et al. (2001) argued that the ENT factor was independent of the frother type and concentration, and froth height."

Jan 1, 2016