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The reactivity of clay minerals and variety of these reactions are greater than any other known colloidal material. While it is acknowledged that clay minerals can cause problems in mineral flotation, the literature contains conflicting evidence, particularly with respect to the effect of clays on froth stability. It is well known that achieving and maintaining optimum froth stability is an influential factor in determining froth flotation performance. However, the presence of clay minerals in the ore is a major challenge to obtaining a stable froth. In fact, clay minerals could reduce froth flotation performance by both decreasing and increasing froth stability. The mechanism by which clay minerals affect froth stability is not fully understood and needs to be investigated further. In order to improve flotation performance, reliable knowledge of the effect of clay minerals on froth stability is essential which is discussed in this paper. Keywords: froth flotation, froth stability, clay, clay minerals

Sep 1, 2012

By J. Y. P. Leite

In the Borborema Pegmatitic Province (Brazil) exploitations of several minerals are conducted by small producers. They use traditional techniques of gravity concentration in small-scale plants as jigs and vibratory tables. During decades the mining activity generated tailings with economic interest in particularly columbite-tantalite. Samples collected in tailing piles of a gravity plant were characterized in mineral composition, which shows in the heavy fraction the minerals spodumene, columbite-tantalite, ilmeno-hematite, garnet and cassiterite. The light fraction presents quartz, feldspar and muscovite. The degree of liberation of spodumene and columbite-tantalite were determined using optical microscopy that presents liberation in 100 µm (90% to columbite-tantalite and 100% to spodumene). Centrifugal concentrator Falcon SB-40 was used for concentration of these minerals and presents 65% recovery in mass to two stages with mass reduction about 85%.

Sep 1, 2012

By G. H. Lind

The Minerals Tertiary Education Council (MTEC), over the past decade, has worked closely with Australian higher education partners in metallurgical education to build capacity in this discipline to deliver high quality graduates for the Australian minerals-industry. This paper explores the benefits of industry engagement through a national innovative collaboration, the Metallurgical Education Partnership (MEP), and specifically the final year Process Design Project (PDP), over the four year period from 2008-2011. Some of the benefits discussed in this paper include outcomes of the student experience during an industry-intensive workshop, collaboration between higher education providers and aligning graduate attributes to meet industry requirements.

Sep 1, 2012

By Sathyaprasad Nanjundaiah

The Paper intends to showcase a framework for spatial data collaboration from multiple sources of data, in order to create a single source of truth across the Organization. The framework is targeted to reduce the data duplicity, re-work, time loss due to search of required data and hindrances to fetch or transfer data from various data sources. The spatial data collaboration will provide a single window view of the entire organization with respect to its operations, management, sales, customers and competitors on a spatial reference across various regions in the World. Large Organizations with cross-country operations can standardize the use of spatial data through this framework for ease of data access, increasing the data reliability / integrity and better / on time decision making. Keywords: spatial data, GIS, collaboration, framework, mining, ESRI, tab files, shape files, ETL, reliability, integrity, interoperability, geo data, geo database, single source of truth

Sep 1, 2012

By M. Etelapaa

A new approach to controlling the process of selective flotation of sulphide minerals from pyrite in a lime environment is covered in the presentation. Advantages of process control based on the electrochemical potential of slurry controlled by ?? ? electrode are proved and compared to conventional methods of ?? ? metering and conductometry. Keywords: flotation, electrochemical potential, automation dosing system, neural network

Sep 1, 2012

Opportunities to monitor and control primary grinding mill performance are strongly sought after in the mineral processing industry. Currently, limited on-line information about mill charge motion and content is available to mill operations for control purposes, leading to periods of lower throughput, instability, variable product size and accelerated mill liner and lifter wear. In response to this need, CSIRO has developed an on-line surface vibration monitor for primary grinding mills which produces data that has been shown to provide new information about the mill charge in terms of toe and shoulder position, as well as potentially key features such as the overall charge level, the distribution between rock and balls in the mill, and the impact of the charge on the mill liners and lifters. This paper outlines the key features of the on-line monitor system, particularly those relating to data transmission, data analysis, and the design of the monitor and its independent power supply. It describes the coupling of single vibration sensor data from the CSIRO on-line monitor to the actual operating conditions of a SAG mill and how the vibration response and hence mill operating conditions vary as a function of time, including during mill equipment failures such as a broken discharge grate. Opportunities for improved mill control based on the data from the on-line monitor are also discussed, as well as the implications in terms of mill processing and maintenance performance. Recently a CSIRO monitor was also installed on a ROM ball mill and analysis of the vibration sensor data from this installation is currently underway. Preliminary findings from this installation will be presented along with comparisons of generic information, such as toe position (measurement precision and operation variability) and vibration signal (intensity, sensitivity and operation variability), between this type of primary grinding mill and AG/SAG mills.

Sep 1, 2012

By Yuri L. Nikolaev

The treatment of placer gold with fine gold, associated with gold-bearing sulfide minerals, heavy minerals and oxidized minerals such as manganowolframite (gubnerite) is not an easy task. In this case, this complex material cannot be treated using physical separation methods such as deep concentration and finishing, magnetic separation and solvent extraction. This technology is usually employed in gold washings finishing plant. The easiest way to recover precious metals in the form of an easy-to-sample saleable product is metallurgical treatment. This paper describes the application of pyrometallurgical processes with oxidative roasting, re-cleaning of cinders (if required) and ore-thermal smelting for producing gold bullion. Hydrometallurgical treatment of slags as an additional operation is recommended in order to maximize recovery of valuable metals. After this treatment, a barren leaching cake rich in PGM can be sold in the market. PGM can be collected as gold-silver alloy during smelting which allows the phase formation of polymetallic matte due to specific composition of fluxes. The PGM are then in the form of saleable gold bullions in the refinery.

Sep 1, 2012

Poor floatability of fine particles is known to be the main cause of the low recovery of ilmenite in Panzhihua, which is the largest titanium mine of China. To get an optimum ilmenite recovery, selective flocculation, and flotation of fine ilmenite was investigated through flotation tests, particle size analysis, zeta potential tests and scanning electron microscopy. The results indicate that carboxymethyl cellulose (CMC) shows flocculation effect for both ilmenite and titanaugite without selectivity, while selective flocculation could be realized by the combination of water glass and CMC. It is because that competitive adsorption would take place on these two kinds of mineral when water glass and CMC are used together. On the surface of ilmenite, the adsorption ability of CMC is stronger than that of water glass, so that CMC can absorb to the same extent irrespective of the presence of a pre-adsorbed layer of water glass and ilmenite particles is flocculated by CMC. The same cannot be said of the titanaugite phase as water glass strongly adsorbs onto the titanaugite, and the adsorption of CMC is hindered. Therefore, the titanaugite particles keep dispersion. Furthermore, the flotation of fine ilmenite particles is feasible as the ilmenite floccules could react with sodium oleate. In the flotation separation of Panzhihua ilmenite ore, the recovery of TiO2 increased from 52.63% to 68.28% by selective flotation. Keywords: ilmenite, flotation, selective flocculation, adsorption

Sep 1, 2012

By M. Vulkov

The paper is focused on the optimal selection of grinding medium for a drum mill. The decision-making is based on the fuzzy multiple attribute approach. One way to optimize the grinding process in a tumbling mill is associated with the development and testing a new shape of grinding body. Family of new grinding bodies ? spheroidal tetrahedrons (tetraballpebs) has been manufactured. Two types of spheroidal tetrahedrons and a classical ball (sphere) with one and the same weight are compared. A fuzzy entropy method to calculate the weight of the attributes is suggested. A grinding body which is the best approximation to the fuzzy formulated technological conditions is selected. Keywords: grinding, spheroidal tetrahedrons (tetraballpebs), balls, fuzzy sets

Sep 1, 2012

By H. G. Hedlund

Tailings in Mining Industry can be handled in different ways. Today tailings disposal is in focus by projecting new plants as well as treating and handling of old Tailings dams.The trend today is to process minerals, detoxify the Tailings and place them as dry surface Deposition or Underground Backfill. This paper will briefly present five different Mining plants in North and Central America, where Tailings have to be dewatered for dry depositing. The Metso-Sala VPA is a filter especially developed for dewatering and drying of Mineral Concentrate and Mineral Tailings. Keywords: tailings disposal, dewatering, drying, mineral tailings

Sep 1, 2012

By John A. Herbst

The Mineral Processing Industry needs accurate Production Simulators for the design of future plants and expansions. To achieve this, these simulators should not only provide an accurate portrayal of the dynamics of individual pieces of equipment they should include the impact of discrete stochastic events such as scheduled and unscheduled maintenance so the relationships between availability, equipment sizes, and plant capacity are understood. To provide such a tool accurate dynamic Population Balance Models need to be combined with solid discrete event modeling. The current paper provides a description of how these two disparate modeling techniques were combined and the associated benefits from this combination. Keywords: dynamic plant simulation, population balance models, discrete event models, prefeasibility and feasibility studies, plant design and expansion

Sep 1, 2012

By P. Matias

The study involved two projects that will produce copper concentrate and may have their operations integrated. Transport by trucks, conveyor belt, and the equipment called RopeCon were evaluated as options for the ore transport between the sites. A rainforest stretch, that Vale S.A. demands to preserve, is situated between the projects. It was suggested to further review RopeCon because it presents minimal interactions with the environment. To design the preliminary system layout, a research was done on the rainforest cover height data, but the information found was scarce and imprecise. For preserving the local forest, the use of this data would conduct to the oversizing of RopeCon towers and, consequently, overestimation of its costs. For the acquisition of reliable information, a method was developed using local data acquired through airborne laser survey. The volume between the digital surface and terrain models was calculated to generate a surface representing the forest cover height. It was revealed, by plotting the points obtained from this surface, that 85% of the vegetation is below 25 m. This height is suggested to review the preliminary project with a more accurate design of the equipment towers, thus reducing its costs estimates. The method permits the precise location of the large trees, making easier to find a pathway, for linear-shaped facilities, that would minimize the creation of vegetation-free zones as a measure to protect equipments against falling trees and forest fires. Keywords: forest cover, mining projects facilities, digital models, airborne laser survey

Sep 1, 2012

By Eberhard Gock

The worldwide implementation of corrosion protection of low alloyed automotive metal sheets by zinc coating has led to supply shortages of zinc free non-alloyed steel scrap in the foundry industry. In a collaboration project, partly financed by the German government, with partners from the automotive industry, zinc metallurgy, scrap trading, foundry industry, and plant construction, a new acid-based pre-dezincification process has been developed, and a pilot plant with throughput of about 100 t/d has been put into operation at the Clausthal Umwelt-Institut GmbH (CUTEC) together with the Clausthal University of Technology in Germany. During the treatment process, acid from a zinc metallurgical plant will be supplied, which can be recycled to the primary zinc extraction process after raising the zinc concentration to more than 130 g/L zinc. This way, the separation of small amounts of iron by precipitation and the electrolytic zinc winning are outsourced and, as a result, the pre-dezincification process runs waste-free. In Germany, the amount of zinc coated ?new scrap? is approx. 3 million t per year with a zinc content of approximately 60,000 t per year. The possible additional incomes for the dezincified steel scrap are in the order of ?40 to ?50 per ton of scrap, the gained zinc content during the acid dezincification defrays the costs of the process, if the throughput is more than 700 t/d. In comparison to conventional dezincification during the electro arc furnace process followed by upgrading in a rotary kiln (Waelz process), the acid dezincification process running at a maximum of 50°C will cut the energy costs by up to 74% and the CO2 emission by up to 88%. In fact, a demonstration plant is being designed right now and will be installed for processing a part of the zinc coated metal scrap from the Volkswagen AG in Wolfsburg, Germany. Keywords: steel scrap, zinc-coated steel, dezincification methods, acid

Sep 1, 2012

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 David Morrow

Fly ash is a by-product from coal-fired power stations that is captured from the exhaust gas stream by electrostatic precipitators (ESPs) or bag houses. It is mainly derived from the inorganic components in coal but also contains residual carbon from unburnt fuel (measured as LOI). In the past, nearly all fly ash was sent to landfills or tailings ponds by power generators but this trend is quickly changing due to landfill costs, sustainability requirements and the inherent value in correctly processed fly ash. The main property that makes fly ash suitable for recycling is its use as a pozzolan. Pozzolans exhibit cementitious properties that make them suitable for partial cement replacement, and that can have beneficial properties for concrete mix designs. Fly ash can be used to replace up to a third of the of the Ordinary Portland Cement (OPC) requirement. Suitable fly ash nearly always requires the removal of the less reactive coarser fraction from the finer fraction. Due to the pozzolanic nature of fly ash, it must be processed dry and separation is normally required at 45 micron. In response to the increasing demand from a range of dry classification applications, Metso purchased an established air classification technology suitable for both mining and construction applications. The classifiers intelligent design efficiently utilizes the air flow which keeps power requirements low whilst including a scrubbing/recirculating function within the classifier that allows extremely efficient separations even at very fine sizes. This technology is of global interest to Fly Ash processors, but should be of particular interest in India which is both the second largest cement producer in the world as well as producing 80% of its power from thermal sources. This paper is intended to give a brief overview of fly ash and requirements for use as a pozzolan, air classification of fly ash and a case study from an established and experienced fly ash producer. Keywords: air classifier, fly ash, pozzolan, fineness, cement, cholla, salt river materials group

Sep 1, 2012

By Ying Gu

Automated mineralogy methods and tools, such as the Mineral Liberation Analyzer (MLA) and the QEMSCAN, are now widely used for ore characterization, process design and optimization. Several case studies published recently demonstrate that large gains can be obtained through grinding and flotation optimization guided by automated mineralogy data. However, since automated mineralogy can only provide the information pointing to where the process gains can be made, it does not directly impact the production gain. Thus, a question is often asked: how to value the contribution of automated mineralogy to process improvement of a particular plant. This appears to be a difficult question. On close examination however, it is found that this is essentially a question of the value of information and it is reasonably well documented in various other industries. Hubbard (2010), in chapter 7 ?Measuring the Value of Information?, dealt with exactly this type of problem. The value of information is the reduced risk of an investment and opportunity loss. The methods Hubbard developed can be applied to estimate the value of automated mineralogy, as well as metallurgical test work, which also produces information that reduces the risk of investment. This paper first introduces Hubbard?s theory on the value of information and how to measure it. It then applies his methods to estimate the value of automated mineralogy, using Anglo Platinum?s fine grinding project as an example. In this case, the value of automated mineralogy includes the reduction in investment risk worth US$ 62.5million, in project rejection worth US$197 million and in opportunity loss worth US$320 million. In the end, a general model is developed to allow the simulation of the value of automated mineralogy in different mining operations constrained by different parameters.

Sep 1, 2012

It is well known that the crushing and grinding steps in the mineral processing of ores represent a substantial proportion of total energy, cost and carbon emission in mining. For instance a recent study calculated that 36% of the energy consumed by gold and copper producing mines in Australia was attributable to comminution (Ballantyne et al, 2012). Understanding this component of a business is essential in a world seeking to lower production costs, improve earnings and reduce its carbon footprint. The issue commands the attention and support of industry leaders in the mining sector, government, equipment manufacture, engineering design and research organizations. Furthermore, several researchers have often stated that globally, comminution processes consume between 3-4% of the world?s electrical energy production (Daniel and Lewis-Gray, 2011). In 2009-10, Australia?s Federal Government Energy Efficiency Opportunity (EEO) participants in the mining sector used 336.5 PJ, representing approximately 6 percent of Australia's total energy use. It is evident that the current practices of breaking rocks in tumbling mills are relatively inefficient (Fuerstenau and Abouzeid, 2002). Research and improved engineering design has established that a range of improved blasting, crushing and grinding techniques and flow sheets may lower project costs and carbon footprint. These include relatively simple process flow sheet strategies such as gangue rejection or pre-concentration prior to size reduction, a better combination of grinding technologies (both current and new systems), and selection of coarser grind sizes where ore and waste mineralogy allow. Yet, despite this systematic and detailed research, the industry remains somewhat reluctant to implement these strategies. CEEC (Coalition for Eco-Efficient Comminution) was established in 2011 to support knowledge sharing and change in an area of high-energy consumption for the global mineral industry. CEEC is a not-for-profit industry company, funded by grants from world wide industry companies, whose mission is to accelerate knowledge and technology transfer in the field of energy-efficient comminution. The key benefit to the mining sector arising from CEEC?s activities will be an increase in the rate at which more energy-efficient comminution data sets, processes, and technologies are developed, demonstrated, shared and applied. This will contribute directly to the industry?s target of reducing operating costs and carbon emissions. CEEC International Ltd and JKTech Pty Ltd teamed together to facilitate the inaugural CEEC Workshop, in June 2012. The purpose of the workshop was to produce a roadmap to provide guidelines for how (1) operations can achieve best EEC practice in the short to medium term, in collaboration with vendors, engineering companies and other service providers, and (2) what R&D is needed to achieve paradigm change in EEC in the medium to long term, e.g. 75% reduction in comminution energy in 10 years.

Sep 1, 2012

By Baidyanath Mandal

Technology in the solid-liquid separation industry has evolved rapidly during the last fifty years and from the beginning, DIEMME Filtration has played a very important role in this evolutionary process by developing innovative solutions, which are used for a diverse range of industrial applications. Since the last decade, we find more and more examples of filter presses employed in the mining & mineral processing field, where high performances in terms of productivity, dewatering capacity and mechanical strength even in extreme working conditions are required. Mainly the requirement of such high quality equipment comes from the Process, however in few cases the reason could be linked with the environment. For stringent process applications like Mineral Concentrates dewatering & leached Slurry Filtration, it requires a high quality & extremely reliable equipment. In these applications, since many years industries are achieving the desired result by using Diemme Filter Presses. Also, recently, due to stringent environment practices are been applied globally, industries needs equipments which could dewater a high amount of residues / tailings with minimal moisture content in the filtered cake. In comparison to all the conventional dewatering equipments, Diemme Filter Presses are most efficient for these kind of product & applications. Diemme Filtration is a highly professional & technological company with several decades of experience in designing equipment for mineral processing. We take up each project as separate & design and manufacture equipment based on individual process or project requirement. This presentation will be focused on the Solid-Liquid separation technologies & equipment Diemme Filtration offers to the mineral processing Industries. It consists of Diemme?s History, Global Network, Technologies & Expertise, R & D Capabilities, Manufacturing Range, Some Applications & results on different mineral processing. Keywords: solid-liquid separation, filtration, dewatering, filter press

Sep 1, 2012

By Rajamani R. K.

The design of tumbling mills has progressed from the Bond work index concept of the 1950s to the population balance concept of the 1980s and then made a quantum leap forward with the discrete element method in the 1990s. The failure of a SAG mill at the Grasberg mine site set in motion the inquiry into the role of shell lifter geometry on the profile of the charge motion within the mill. Quickly, it became evident that this could only be accomplished by tracking individual motion of ore particles and grinding balls and not by study of en masse motion of the charge that had been established previously. The discrete element method (DEM) which was prevalent in the civil engineering literature at that time proved suitable to tackle this simulation problem. In 1991, the two dimensional simulation of laboratory scale mills was validated with the DEM. Later this simulation method evolved into ?MillSoft?? a simulation software package for the design of lifters in ball and SAG mills. MillSoft?simulations proved that cataracting charge motion is not conducive to the life of lifters. The old rule of thumb that the number of shell lifter rows should equal twice the diameter of mill in feet was shattered by simulation results. Instead, the number of rows equal to the diameter of the mill in feet, providing that the lead angle of lifter is around 25 degrees, was established as being more optimal. This bold design change was first implemented and tested by Mark Sherman at Alumbrera Mines in Argentina. Two 36-ft SAG mills responded extremely positively to the design change. This success was immediately repeated at Collahuasi, Pelambres and other mines in South America. The design change has so far exceeded expectation that there is not a single SAG mill around the world today that does not employ a relief angle on its shell lifter. The DEM method has advanced in the hands of the author, mining companies and universities, notably in Australia and South Africa. Today, three-dimensional simulation of charge profile and slurry transport is a standard in the design of mills. There is strong pursuit of a virtual comminution machine with DEM in Australia. In South Africa, an experimental method known as positron emission tracking is emerging as a method for tracking particles in grinding mills. The computational burden of computing with millions of particles in three-dimensional simulations has been eased to less than a day with a technique known as GPU computing. Keywords: DEM method, GPU computing, SAG mill, tumbling mill simulation, discrete element method

Sep 1, 2012

By Carsten Gerold

The paper is giving an overview about successful operating Loesche Vertical ? Roller ? Mills (VRM) installations and summarises the main benefits of the dry compressive Loesche grinding technologies in Airflow- and Overflow-Mode. Some of these benefits are optimised energy efficiency of the grinding - classifying - circuits, increased mineral recoveries and decreased OPEX costs, at a parallel simplification of the process route. Within this paper the process values of the Loesche VRM are compared to existing or planned conventional grinding ? classifying circuits. Further advantages discovered in pilot trials and examples for new more efficient process route alternatives are given. The paper reports about production and pilot trial experiences obtained by crushing and grinding Iron Ore, Iron Ore Concentrates, Copper Shale, Copper Matte, Copper Slag, Titanium Slag, Tin Slag, Steel and Stainless Steel Slag with Loesche VRM.

Sep 1, 2012