Search Documents

AFRICAN NATIONAL COMMITTEE ON TUNNELLING In 1970, the South African Institution of Civil Engineers, the South African Institute of Mining and Metallurgy, the South African Institute of Mechanical Engineers, and the Geological Society of South Africa held an international conference on tunnelling, known as Tuncon 1970. SUID-AFRIKAANSE NASIONALE TONNELBOUKOMITEE In 1970 het die Suid-Afrikaanse Instituut van Siviele Ingenieurs, die Suid-Afrikaanse Instituut vir Mynbou en Metallurgie, die Suid-Afrikaanse Instituut van Meganiese Ingenieurs en Die Geologiese Vereniging van Suid-Afrika 'n internasionale konferensie in verband met tonnelbou gehou, wat bekend gestaan het as Tonkon 1970.

Jan 5, 1974

By C. J. Lenz

The results of prospecting operations involving geological data and a large number of geochemical determinations of the metal content of soil samples are plotted and evaluated by computer. Anomalous areas are identified in each type of environment by selecting probability or population boundary values from frequency distributions. The anomalies are plotted to permit correlation with geographical or geological features. Ranking of prospecting targets is made using geographic pattern, geology, absolute value and metal ratios. Three short case histories are presented.

Jan 1, 2014

The March General Meeting of the Institute was held in Kelvin House, Johannesburg on 18th March, 1970, at 4.30 p.m. Mr J. K. E. Douglas (President) was in the Chair. There were also present fifteen Fellows, Messrs H. Britten, R. C. J. Goode, Prof D. D. Howat, Mr T. C. A. Meyer, Dr R. E. Robinson, Messrs V. C. Robinson and P. W. J. van Rensburg (Council Members), S. K. de Kok, Dr N. P. Finkelstein, Messrs K. W. Findlay, H. N. Hepker, J. Levin, Dr K. A. Murray and Mr A. H. Mokken. Four Members including Mr D. Ayres, Dr M. I. Britten and Dr A. Granville. One Associate: Mr G. S. Stander. One Student, Mr R. N. Guest. Four Visitors, Messrs S. A. Allison, C. N. Leibb, C. J. Kooij and A. Mavrogordato. Secretary: Mr D. C. Visser. Total present: Twenty-seven. OBITUARY The President: "It is my sad duty to announce the death of Henrik Johannes Van Eck, Honorary Life Member, who joined the Institute in 1929 and passed away on 18th February, 1970. Dr van Eck started life as a chemist and chemical engineer and, as we all know, he rose to become one of our most distinguished leaders of industry in the country. On many important occasions we, in this Institute, have been privileged to have him address us on subjects which were always of great importance and relevance to the developments in this country. He was a man of great vision and imagination and could put across his ideas in a most eloquent and convincing manner. In his important position as chairman of the Industrial Development Corporation and of Iscor, whatever he said carried great weight. Busy as he was he always found time to participate not only in the affairs of this Institute but in many other technical and public bodies. His passing is a great loss to South Africa and we in this Institute wish to associate ourselves with the many other tributes which have been paid to this great man. We extend our sympathy to his wife and family and as a mark of respect I would ask you to rise and observe a few moments silence." MEMBERSHIP The President: "I have much pleasure in announcing that the names of the undermentioned candidates, having been published in accordance with By-Law 5.2.2, Council has elected them to membership of the Institute in the following grades: Fellow: Ian Douglas Bruce Corner, Joachim Bernhard Rolfes. Member: Michael Vernon Nolan. Associate: Karl Franz Wilhelm Eick. MEMBERS TRANSFERRED TO A HIGHER GRADE From Member to Fellow: Nilo Zolezzi. From Graduate to Member: Roger Billingham. I welcome the newly elected members to the Institute and congratulate the members who have been transferred to a higher grade." PAPERS FOR PRESENTATION The President: (i) "Mr Lee, may I call on you to deliver your paper entitled 'A new bubble pick-up technique as a rapid flotation test method'." After the presentation of the paper the President said: "The paper which Mr Lee introduced this afternoon was a short one but was nonetheless important in that it described a new tool for use in flotation test work. Those of us who have experienced the frustration of trying to solve flotation problems by trial and error methods know what this means. I well remember 25 years ago at T.G.M.E. trying to improve the recovery from the flotation plant there by trying various combinations of reagents and then having to wait a couple of days for the assay office to give results. Even then, on the small scale laboratory tests which had to precede full scale tests one could never be sure that the results obtained were reproducible on the full scale. Here it seems we have a relatively simple apparatus which can measure instantly the effectiveness of various reagents under different concentrations and pH values, etc. It is most important, I believe, that developments of this kind be reported in our journal for the benefit of all involved in such work, not only so that we know about it but also in order to provoke constructive discussion which might lead to further developments. I would like to invite members, therefore, to submit papers or notes on important

By Z. Botha

Sheryl Sandberg, the COO of Facebook, published a book titled 'Lean In', where she invites women to sit at the table. In summary, to 'sit at the table' entails not only embracing opportunity, but to actively seek out opportunities in leadership positions. Sandberg points out that, unfortunately, apart from institutional obstacles, a woman's own perceived limitations have a negative impact on her leadership ambitions. To create an environment where diversity will flourish, where everyone has a seat at the table and everyone has a voice, safety must be established first. To establish safety within a diverse team, there is power in relationships and connections. This study will first and foremost review theories in literature as to why diversity and inclusion are so important and the value that diversity brings to our industry. The study also recommends a few focus areas for improving diversity and inclusion in the industry.

Sep 1, 2022

By F. Yang, S. S. Long

Mixed fatty acids, such as oxidised paraffin soap, are frequently used as a substitute for oleic acid in flotation of scheelite in China. Not only because it is cheaper than oleic acid, but also because it is superior in flotation performance to oleic acid. This superiority is generally attributed to the mixed fatty acids' synergistic effect. In this paper, the synergistic effect of oxidised paraffin soap was investigated. We found it mainly consists of a series of saturated fatty acid salts, with six to nineteen carbon atoms. All the contained fatty acids were classified into four groups based on their chain length to make the research work practical. Also, the groups were labelled as 1, 2, 3, and 4 in order. The research was simplified into studying the synergistic effect of four equivalent collectors, instead of fourteen fatty acids. It is justified by the fact that neighbouring fatty acids are expected to have a similar flotation performance. The synergistic effect of the four groups of fatty acids was studied by single-mineral flotation with single groups, binary mixtures, ternary mixtures, and the full component, as collector respectively. The flotation performance index and synergy value were introduced to evaluate flotation performance and synergistic effect of groups, respectively. The results show that the mixture 1+2+3 has the strongest synergy of all followed by the mixtures 1+3 and 2+3. The mixture 3+4 and 1+2, on the other hand, have negative synergy. The synergistic effect of mixtures of groups indicate that being consecutive in length and a broad range of lengths are vital for fatty acids to enhance synergy. Group 3 is fundamental for the collecting action of 733 oxidised paraffin soap in the flotation of scheelite. The fatty acid soap in group 4 is not suitable for flotation due to its low solubility. Keywords: Mixed collectors, synergistic effect, scheelite

Jan 1, 2020

By H. Ogasawara

Information on rock stress is important for safe mining in seismically active ground. On a major gold mine, a few tens of crews are continuously conducting geological drilling with small pneumatic machines. However, stress measurements are not often carried out in South African deep-level gold mines. One of the reasons is the drilling diameter that overcoring requires, which is much larger than the diameters used in regular geological drilling, e.g. Boart Longyear Metre Eater, which drills AQ or BQ holes. Larger diameter holes result in slower drilling advance, more load in transportation and handling at sites, and higher cost. In order to enable overcoring in BX size (60 mm diameter), we modified the compact conical-ended borehole overcoring (CCBO) technique that has been suggested by International Society for Rock Mechanics (ISRM) and was originally designed for NX drilling (76 mm diameter). With a single overcoring, the 3-D stress tensor can be determined. We tested this modified method at a depth of about 3 km at Moab Khotsong mine in South Africa. We worked with drilling crew who usually work at geological drilling with the Metre Eater. In January 2011, we tried using regular geological drilling tools (a sequence of a normal BX bit, reamer, and rod) without success. In August and September 2011, introducing stabilizers and thin BX bits, we succeeded. We could complete a cycle of procedures necessary for an overcoring, including shaping the borehole-end conically, glueing a 16-element strain cell, and overcoring, within 2.5 hours. Only 10 cm overcoring is needed, which increases the chance of successful overcoring in heavily fractured conditions. This modified method is suitable for up-dip holes to depths of 10-15 m from tunnels, and has the potential to be widely used at the initial stage of geological exploration drilling at many localities.

Jan 1, 2012

By D. N. Esfahani, K. Khazen, M. Mohammadi

Electrowinning is one of the nickel recovery processes from solutions obtained from the leaching of nickel sources. Every year significant amounts of nickel products are used in various industrial processes and daily life, such as catalysts or batteries, which are a valuable source of nickel for recovery. Nickel purity is also very important in the electrowinning process, because the amount of impurities in nickel such as sulphur, if greater than 100 ppm, make it unsuitable for use in catalysts and plating. Because sulfur is intrinsic to the sulphate electrowinning system, we needed to investigate parameters that can affect the quality and purity of nickel. In this regard, experiments were performed in static and circulating electrowinning processes. A monitoring and circulation system was designed and built to measure voltage, current and temperature as well as to circulate the solution in the system at a specified rate. It was then observed that nickel ion concentration, pH, using the circulation system and additives, were factors affecting the purity and quality of nickel, and in the best case the amount of sulphur in nickel was below 100 ppm. Keywords: Nickel, electrowinning, sulphur impurity

Jan 1, 2020

By D. Wines

"Slope stability analyses have traditionally been undertaken in two dimensions assuming plane strain conditions. Although three-dimensional analysis techniques are widely available and used routinely for open pits, two-dimensional analyses are still more common due to the relative ease of model construction and the relatively rapid simulation times.Two-dimensional analyses will often produce different results to three-dimensional analyses for the same slope. It is generally thought that two-dimensional analyses will produce more conservative results. The main reason for the differences is the ability of three-dimensional analyses to account for the three-dimensional nature of the various model inputs, including the slope geometry, the distribution of soil and rock mass domains, the orientation of geological structures with respect to the excavation face, the orientation of the in situ stresses, and the distribution of pore pressure. In some cases, for a long, straight slope in basic geological conditions, two-dimensional analyses can provide a reasonable representation of the problem. However, in many cases, the inability of a two-dimensional analysis to represent the true three-dimensional nature of the problem will lead to unrealistic analysis results.This paper discusses the reasons, as detailed above, for the differences in two-dimensional and three-dimensional analysis results. Work by others is summarized, and additional numerical analyses are performed to provide an improved understanding of the effects of slope geometry, structural orientations, and in situ stresses on predicted stability. Case studies are presented for both stable and unstable slopes, and the behaviour of these slopes is related to the three-dimensional nature of the slope geometry and geology.The previous work, the new analyses performed here, and the case studies show that it is often important to provide a realistic representation of the slope in three dimensions in order to obtain reasonable stability analysis results. This is particularly true for hard rock environments where structurally controlled failure mechanisms are most likely. The paper also highlights the fact that back-analysed properties obtained from one analysis technique are not necessarily applicable to forward analyses using another technique."

Jan 1, 2016

By C. B. van den Berg

n this study, silver and palladium nanoparticulate inks with different metal-binder ratios were screen-printed onto a paper substrate. The printed layers comprised the metal nanoparticles and an ethylcellulose binder. The layers are not typical metal composites due to the low concentration of binder and high porosity. The electrical sheet resistivity of each particle concentration was measured, and the data fitted using the scaling law of percolation theory and the general effective media (GEM) equation. The percolation parameters, i.e. the percolation threshold and the critical exponent, for each system were determined from the fits and compared. The percolation threshold for the palladium layer (39.8 wt%) was lower than that found for the silver layer (44.9 wt%). The critical exponents determined for the palladium and silver layers were both lower than the universal value for three-dimensional percolation systems. Microscopy observations indicate that the difference in the percolation threshold for the two layers can be attributed to variations in their microstructure.

Jan 1, 2014

By J .. F. Brownrigg

In the mining method used at O'Okiep Copper Company (OCC), vertical crater retreat, the prime requirement for the fill is that it should be sufficiently strong to be free-standing to a height of 150 m. Other requirements are minimal decant and drainage water, and high pulp density to allow large tonnages to be placed quickly and alleviate transport problems. The excessively high cost of cement precluded the use of a cement-based fill, and after three years of extensive investigations a backfill based on the smelter slag was produced. Currently a fill with a uniaxial compressive strength of greater than 1 000 kPa after one month is being produced. This is in excess of the design specification of 850 kPa after 2 - 3 months. The research and development which went into the slagfill is briefly covered; the production of the fill from the various raw materials is described; and the design and control systems of the backfill plant, the reticulation system and its monitoring are examined. Finally, the implications of this high- quality fill for the mining programme are assessed.

Jan 1, 1988

By H. Jiang, W. Wang, Y. Zhao, Q. Jinpeng, C. Duan

Dry deep screening is an important method of classifying moist fine mineral. The rigid-flexible coupled elastic screening technology can simultaneously solve the problem of traditional screen surface plugging and the low service life of a screen surface in the process of deep screening. In this paper, two kinds of rigid-flexible coupled elastic screen surfaces were introduced. The structural characteristics of a screen surface were studied. The mechanism of a rigid flexible coupled elastic screen surface to overcome hole blockage was revealed. Finally, 3 mm and 6 mm screening experiments were carried out. When the external moisture content was below 12.79% for the 6 mm dry screening experiment of elastic rod screen surface, the screening efficiency was above 81%. When the external moisture content was below 11.31% for the 3 mm dry screening experiment of elastic screen surface based on ball hitting, the screening efficiency was above 83%. Keywords: Moist fine mineral, rigid-fexible coupled, elastic screening

Jan 1, 2020

By G. Song, X. Liu

The global coal industry has changed significantly in recent years. In this paper we analyse the coal production and consumption, imports and exports, and coal prices in China and other major coal-producing countries during the past four decades. The analysis shows that global coal production and consumption have declined over the last three years, in striking contrast to the continuous growth for most of the past 35 years. Australia, Indonesia, and Russia have become the world’s major coal providers, while China, India, and the USA, and Germany are the major coal consumers. The world’s, and China‘s, coal industry can be classified into four stages of development: the stable growth phase, stable phase, rapid growth phase, and high-quality phase. Coal prices rose in the world’s four major coal markets in 2016 after four consecutive years of falling prices. The elimination of overcapacity and production-optimizing operations in China could assist in achieving a demand and supply balance.

Aug 8, 2024

By Mr P. W. J. van Rensburg

SOUTH AFRICAN NATIONAL COMMITTEE ON TUNNELLING In 1970, the South African Institution of Civil Engineers, the South African Institute of Mining and Metallurgy, the South African Institute of Mechanical Engineers, and the Geological Society of South Africa held an international conference on tunnelling, known as Tuncon 1970. SUID-AFRIKAANSE NASIONALE TONNELBOUKOMITEE In 1970 het die Suid-Afrikaanse Instituut van Siviele Ingenieurs, die Suid-Afrikaanse Instituut vir Mynbou en Metallurgie, die Suid-Afrikaanse Instituut van Meganiese Ingenieurs en Die Geologiese Vereniging van Suid-Afrika 'n internasionale konferensie in verband met tonnelbou gehou, wat bekend gestaan het as Tonkon 1970.

Jan 5, 1974

By F. H. Deist, J. P. E. Morris, E. Georgiadis

For some years the Collieries Research Laboratory of the Chamber of Mines of South Africa has been engaged in the development and application of computer programmes to aid in the solution of rock mechanics problems. It is the purpose of this paper to introduce some of the programmes having general applicability. A system capable of predicting stresses and displacements induced by large-scale tabular excavations is discussed. A finite element programme especially designed for handling layered continuum problems, and which is being used extensively has been supplemented by an automatic mesh generation facility that reduces problem preparation times considerably. Some typical applications of these programmes are described. An entirely new approach, potentially capable of performing linear three-dimensional continuum analysis at practical cost is introduced.

By Y. Tanaka, H. Miki, Y. Aoki, H. Okamoto, G. P. W. Suyantar, T. Hirajima

Due to environmental limitations and the scarcity of freshwater, flotation using seawater or desalinated seawater as process water becomes more common for mining operations. On the other hand, seawater has been reported to affect the flotation behavior of sulfide minerals. Few reports are available on influence of pyrite depression, recycled seawater and lime consumption on flotation by using seawater. In this study, the flotation tests were performed using ore sample to investigate the effect of pH with seawater and process water used in plant on the flotation behavior in a laboratory-scale flotation cell and a pilot plant-scale. The results of laboratory scale flotation indicated that copper and molybdenum flotation kinetics decreased with increasing pH. Furthermore, the iron (mainly pyrite) recovery decreased with increasing pH. The pilot plant-scale flotation test showed that water with a higher concentration of magnesium and calcium (plant processes water) consumed a higher amount of lime. Because of low lime consumption and high copper and molybdenum recovery and grade, pH 8 is suitable compared with pH 8.5 for flotation. Keywords: seawater, process water, copper-molybdenum rougher flotation, pH, pilot test

Jan 1, 2020

By Nelson Sánchez

The Los Bronces Development Project (LBDP) was approved in October 2007 by the Anglo American plc Board at a capital cost of some US$1.74B, and is scheduled to be completed by the end of 2010. The project represents a big step forward for the Los Bronces mine since it will increase the treatment rate by 140%, the mining rate by 64% and almost double copper production during the first four years of the project. This economy of scale will also position Los Bronces as a much bigger and efficient mining operation, better prepared to face adverse market scenarios and allowing Anglo to consolidate its position in base metals. The project addressed numerous scope alternatives such as plant capacity vs mine capacity, cut-off grade strategy to maximise value based on the existing flotation and leaching process, cutback strategy, etc. Main infrastructure aspects of the project are as follows: ?Dump area with 2400Mt capacity for waste and low grade material ?Mining equipment: 1 x electric shovel, 12 x 300t trucks, 1 x drill ?Primary crusher: 60? x 89? ?Three new power lines (144MW capacity) ?Grinding plant at 87kt/day nominal capacity (includes a 4.3km tunnel with a regenerative conveyor belt) ?Grinding plant: 1 SAG mill 40? x 25?, 2 ball mills ?Slurry pipeline (52 km from grinding to flotation plant) with five choke stations ?Flotation plant (rougher, cleaning, regrinding circuits and molybdenum flotation). The history of Los Bronces started in 1867 when it was discovered. In 1978 ENAMI (Government company) sold Los Bronces to Exxon for US$112M. The same year a snow avalanche destroyed San Francisco Flotation Plant. In 1979 the plant was rebuilt at 4.9kt/day and from 1979 to 2002 several plant expansions were made up to 54kt/day capacity. In 2002 Anglo acquired Los Bronces for US$1.3B. The 2002 resource and reserve statement showed reserves at 459Mt at 1.02%CuT and resources at 780Mt at 0.80%CuT. The 2007 statement shows reserves at 1,480Mt at 0.67%CuT and resources at 1,644Mt at 0.45%CuT. Defining the size of a plant expansion is the key challenge that any expansionary project faces. The scope of this paper is a general review of the project, describing all the mining techniques that were used to define the best options that maximise value. In this context, a range of plant capacities (from 58 to 230kt/day) combined with a range of mining capacities (from 83 to 166Mt/a) were evaluated in detail, defining for each option a mine plan, Capex and Opex, and cut-off grade strategy for flotation and leaching processes and the associated Net Present Value (NPV) that was used as the selection criteria. The Los Bronces mineral resources potential provides good growth opportunities for the mine beyond LBDP implementation, offering an exciting invitation to continue studying new initiatives that maximise the value of this deposit.

Jan 1, 2008

By J. -M. Milazzo, T. Wallmach, S. B. Blancher, A. Amalric

In a FeNi electric arc furnace, the physical properties of the slag (chemistry, viscosity, liquid/solid/gas ratio) are of crucial importance in controlling the efficiency of the process. In this paper, we studied the slag crystallised on the walls of a semi-industrial furnace (freeze-lining), the slag rising through the burden during foaming phenomena, and the casted slag. The freeze-lining is the layer of oxides that crystallises on the refractory wall of a furnace, protecting it from chemical and mechanical aggression. It records changes in furnace conditions (slag chemistry, temperature, oxygen fugacity), which makes it possible to observe the impact of these elements. In the high reduction test, the freezing lining is composed of magnesian olivine. Switching to a low reduction process increases the Fe content of the olivine and causes orthopyroxene to appear, making the freeze-lining mechanically and thermally weak. Thermal incidents in the furnace cause significant slag foaming. This foaming is produced by a massive crystallisation of the olivine (due to the drop in temperature), and inducing an exponential increase in viscosity, preventing the free circulation of gases. These foaming episodes are also recorded in the freeze lining and form layers rich in gas bubbles, and therefore mechanically fragile. The slag casted and cooled in a ladle allows the first steps of slag crystallisation to be studied. Olivine is the liquidus phase, with a magnesium-rich core and an iron-enriched rim, contemporaneous with the orthopyroxene phase. The habitus of these phases is very similar to that found in komatiites for the same minerals. FeNi slag is therefore an industrial analogue that is easy to study and compare to komatiites. Keywords: Pyrometallurgy, ferronickel, slag, freeze-lining, characterisation, olivine, mineralogy

Jan 1, 2020

Dr H. J. van Eck (Honorary Life Member): "Mr President, I regard it as a signal honour that I was invited to address the South African Institute of Mining and Metallurgy on its 75th Anniversary. I also wish to add my congratulations and good wishes to the many you have already received on this memorable occasion. Seventy-five years is indeed a good age and the achievements of your Institute certainly justify this special celebration. South Africa owes her present prosperity largely to the technological ability and determination of her own people. Members of the Institute contributed in large measure to this great development of our country and through the years have upheld their high reputation for scientific integrity, dynamic enterprise and dedicated service. It was their knowledge which provided the key to unlocking the mineral wealth which lay dormant for countless ages. The history of world mining dates back many centuries. We know of the mercury mines of Spain, the tin mines of Cornwall and the zinc mines of Poland, but it was not until colonization of the western hemisphere started in about 1500 that mining of any consequence began in North America. It is true that the peoples of South America and Mexico had accumulated wealth out of gold and silver, but industrialized mining was not a feature of these agrarian cultures. The mining wealth that eventually developed in North America was based on advances in the technology of processing minerals and served as an incentive to people in other new countries. Big mines were opened elsewhere in the world. From Canada, Mexico, Venezuela, Brazil, Peru, Chile, Bolivia, Rhodesia, Australia, Burma and India, to name but a few, there has been a steadily increasing production of an expanding range of minerals and metals. By the middle of the 20th century the trend was to increase the production and use of such comparatively uncommon metals as cobalt, nickel, titanium, and others, and a great mining rush started to search for, and develop, the deposits of uranium, and related radio-active minerals. It is worth pausing a few minutes to reflect that most of early mining was based on the recovery of virgin metals like gold and silver or easily treated high grade ores of copper, tin and zinc. Today, much of this type of mining would be regarded as picking the eyes out of the mine. With the development of improved ore separating, ore concentration and recovery processes, we developed into bulk mining and bulk treatment and in South Africa we have some very big mines, also outside the gold mining industry at Phalaborwa, for instance. Mining techniques are applied which compare with the best in the world. These large mines could only develop because of the perfection of new concentrating techniques and, of course, because of the development of markets. We have mentioned nickel and cobalt. These names were given to those mischievous mining sprites called nickels and kobolds to whom the suspicious miners ascribed their inability to smelt copper from copper nickel or arsenious copper ores. In South Africa, the presence of minerals was known to the modern Western world as far back as 1497 when Vasco da Gama found the native 'strandlopers' at the St. Helena Bay wearing copper rings. In 1669, after the British East India Company had formed their settlement, they employed miners and assayers in prospecting for minerals and in 1685 found traces of copper in the copper mountain of Namaqualand where some 170 years later a rich deposit of copper was to be opened up. This deposit also had a chequered

By L. S. Bicalho, W. J. Rodrigues, P. M. A. Rollo, P. R. G. Brandão, W. C. da Silva

Quadrilátero Ferrífero is an important mineral province located in Minas Gerais state, responsible for a substantial amount of iron production in Brazil. Among the concentration methods for iron ore practised by the mining companies in this region, the most important is the reverse cationic flotation. Dolomite iron formations, with the presence of hematite, quartz and dolomite, occur in several areas of mining and, with the deepening of the deposits, this type of ore, with low iron content and more complex mineralogy occurs frequently. Carbonaceous minerals, mainly dolomite, present a technological challenge for the concentration of iron ore by flotation. In the present study, the concentration of iron ore with 6% of dolomite content was evaluated. Bench flotation trials indicated that conventional iron ore flotation is not selective to float dolomite, thus compromising the iron content in the final concentrate. Alternative flotation routes were evaluated, and a selective condition was reached to float both quartz and dolomite using the combination of the cationic collector Flotigam 16424 with an anionic collector Flotinor 16551. It was demonstrated that the flotation of dolomite was improved with the combined use of both collectors in the cleaner stage, and by a previous quartz flotation in the rougher stage. Zeta potential analysis indicated specific adsorption as the adsorption mechanism between Flotinor 16551 and dolomite, confirming the high selectivity observed in the bench flotation tests. Keywords: Flotation, iron ore, dolomite

Jan 1, 2020

By R. o. Cretier, L. A. Cisternas, A. López-Valdivieso, F. Valdes, E. Gálvez, G. Gahona

The size of the particle plays an important role in the flotation of minerals. Comminution allows the release of valuable species and their subsequent recovery. Then, the degree of concentration and recovery will depend on the size of the particle. In this work, we investigated the flotation of coarse particles (-850 +150 μm) of copper ores when using the fluidized-bed separator (HydroFloat® cell) and compared it with the process of conventional flotation with medium size particle (-150 μm) (Metso cell) using seawater. The collector concentration was the main variable studied in terms of copper recovery. The results show that the flotation of coarse particles is feasible using seawater without frother

Jan 1, 2020