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By Jorge Misle, Daniel Silva

"This paper addresses the need for advanced control technologies and strategies in the mining industry, its potential and actual impact on mining processes and the best practices for their implementation, operation, and long term sustainability. It is well known that advanced process control (APC) can be a very good source for incremental process improvement for the mining industry, yielding to higher production rates or helping maintain consistent production rates despite ore changes. The application and integration of new technology, process knowledge and innovation are key elements in building such a supporting structure. More specifically, and this cannot be emphasized enough, the correct application and assembly of control tools, the in-time presentation of key data to decision makers and the development of relevant statistics and KPI’s (key performance indicators) can and will make a difference not only in terms of production, but also in plant stability, availability and production costs. In deploying such ideas and aiming at the long-term goal of "Operational Excellence", Minera Los Pelambres (MLP) has developed a number of successful control strategies, best practices and technologies, which are not only the application of state-of-the-art automation and computing tools, but rather the assembly of the above presented structuring factors. This work discusses some of the key tools and ideas implemented for SAG & Ball milling and Flotation areas, their performance results and the roadmap taken for the integration of process knowledge and control tools. Also, cases studies are presented and discussed further to not only show the main areas of improvement, but also to highlight the benefits of such strategy that for the most part, deviate from the traditional mining industry control approach. Also, a word is given on the need for innovating in the design of control strategies and leveraging best practices and process knowledge that ultimately, will contribute to long-term reliable operations, improved mineral processing and, although unmeasured, lead to a superior overall performance and productivity of all mining personnel involved."

Jan 1, 2014

By G. Y. Liu

The structure-activity relationships for four thionocarbamate collectors are discussed in this pa-per. These collector classes are alkyl alkyl thionocarbamates, allyl alkyl thionocarbamates, acyl al-kyl thionocarbamates and alkoxylcarbonyl alkyl thionocarbamates. The main emphasis will be to highlight the differences between collectors and their affinities for copper and iron sulfide minerals on the basis of data on electronic-structure properties obtained by vacuum and solution density functional calculations, flotation experiments and analysis measurements. The mechanism of interaction of these collectors with sulfide minerals is also discussed with perturbation theory. The theoretical study results indicate that acyl alkyl thionocarbamates and alkoxylcarbonyl alkyl thionocarbamates have best performance in these agents as flotation collectors with improved collecting power for copper sulfide minerals and excellent selectivity against iron sulfide minerals, which are consistent with the experimental data reported in the literature.

Jan 1, 2014

By Jilai Xue, Jun Zhu, Liang Liu

"Separation removal of fluorite and calcite from scheelite is a difficult technical operation in current industrial practice with a heating process causing large energy consumption and high production costs. In this work, the floatation separation at room temperature were carried out using two types of skarn scheelite ores. The results showed that CaO and Na203 are better than NaOH as a regulator in pH value. In the rough floatation and first cleaning floatation, CaO (500g/t), Na203 (3000g/t) were used as a pH regulator, waterglass (4000g/t) was as a gangue depressant, oleic acid or sodium oleate were used as a collector. The degree of the obtained W03 concentrate was more than 65% (commercial product).IntroductionThe mainly gangue in scheelite are quartz, calcite, barite and some rare metal ores. There are three main types of scheelite for floatation: scheelite--quartz (silicate minerals) type, scheelite-calcite/ fluorite type, scheelite--calcite/fluorite/barite type. Generally speaking, scheelite--quartz type is separated easily, and others are difficult, on the contrary. The last two kinds of scheelite are always called scheelite--calcite/fluorite (barite) type, because there are similar floatation ability and floatation process between them. Scheelite, calcite and fluorite have same cation - Ca2+, it makes them have close floatation property [1]. Separation removal of fluorite and calcite from scheelite is a difficult technical operation in current industrial practice.The traditional separation method is a heating floatation process (Petrov's process) [2]. It can deal with many kinds of scheelite, and can be obtained stable quality ofW03 concentrate. On the other hand Petrov's process causes large energy consumption, high production costs and bad operational environments. Since 1980s, scheelite ambient temperature floatation has become the mainstream of study [3]. Nowadays more and more studies on scheelite floatation focus on complex reagent system [4, 5], rigid operating rules and at the same time development new regulator [1, 5]. Some research show there are new regulators can concentrate scheelite efficiently, but it may cause high costs, potential pollution and difficulty to spread. Oleic acid and sodium oleate used as collector have high adsorption capacity to scheelite, but same to calcite and fluorite[6]. So, it would not get ideal effect for separation of scheelite. In this work, the floatation separation at room temperature were carried out using two kinds of skarn scheelite ores. Calcium oxide and sodium carbonate was used as a pH value regulator, waterglass was used as a depressant and Oleic acid/sodium oleate was used as a collector. The result of experiment showed that the degree of the obtained W03 concentrate was more than 65% by one time ambient temperature roughing floatation, several times ambient temperature cleaning process."

Jan 1, 2014

By C. Joulian, A. G. Guézennec, A. Chmielarz, Y. Ménard, M. Hanke, P. d’Hugues

"The copper concentrate used in this study is produced by flotation of a black shale organic rich ore. This resource is a carbonate-rich, polymineral concentrate. In the last 5-6 years, ore characteristics changed and the concentrate grades degraded. This study evaluated bioleaching of the concentrate in stirred tank reactors as an alternative to the pyrometallurgical technology that is currently applied, and which may no longer be feasible in future given the concentrate chemistry.The first part of the study focused on testing non-traditional operating conditions during continuous bioleaching experiments: high solids concentration (> 20% solids), reduced agitation and aeration rates. For the same residence time, bioleaching performance at high solids loading (25%) was the same as that reached during previous bioleaching experiments at 15% solids. No mixing or microbial issues were encountered. The bacterial consortium used in the experiments demonstrated a high copper tolerance.The second part of the study was devoted to technology development for metal recovery from copper bearing solutions obtained during bioleaching experiments. Due to the high copper concentration of the leachate, solvent extraction prior to electrowinning was not necessary. After iron removal, high quality copper cathodes (morphology and composition) were obtained from the PLS by electrowinning."

Jan 1, 2014

By Zainelabdin Khalid Zainelabdin Elfaki

The influence of partially replacing cement with marble waste on the workability and compressive strength of concrete bricks was investigated. Three replacement percentages, 10%, 20% and 30% weight marble waste, were used with different curing times of 7, 14 and 28 days. Two specimens were prepared for each percentage and curing time. For this study, marble powder from the Mining House Company in Saudi Arabia was used. It was observed that the replacement of cement in Concrete brick with marble waste enhanced the loading strength and the workability of the prepared concrete bricks. It was also observed that 20% replacement of cement with marble waste was the best replacement percentage compared to the other replacement percentages tested. Marble waste from manufacturing companies, either in powder, sludge or slab form, has negative impacts on the environment. In contrast, reusing marble waste has both economic benefits (i.e., selling the marble waste) and lessening the need for raw resources.

Jan 1, 2014

By A. Bastrzyk

Text The mining and refining of minerals generates large amounts of solid waste. The waste from cleaning operations constitutes up to 90% of the total production. Although some of them can be used in mining, civil enegineering, construction, agriculture, most of them must be disposed in dumps and slurry ponds, causing major economic and enviromental problems (Alonso, 2002; Alon-so, 1999). The refuse from minerals cleaning may have considerable valuable particles content, which can be used in industry. Thus, the recovery of these particles from minerals waste by using a cleaning method effective at fine particle size, may overcome these consequences. Surfactants are used in numerous applications including emulsification and solid surface modification. In the oil agglomeration of minerals, the ionic surfactants (both anionic and cationic) are used for the hydrophobization of mineral surface and the oil-water emulsion preparation. When the cationic surfactant is injected into the oil-water mixture, surfactant molecules adsorb at the oil-water interface, changing droplets? properties. The addition of anionic surfactant to the mineral suspension was found to modify the solid-liquid interface. In this paper, the condition and mechanism of selective separation of magnesite from quartz are presented. A satisfactory was achieved with the amount of anionic collector (sodium oleate) equal to 15.2 mg/gsolid and with the amount of cationic collector 27.9 mg/gsolid for cetyltrimethylammonium bromide (CTAB) and 16.9 mg/gsolid for dodecyloammonium hydrochloride (DDAHCl) at pH 8. At these conditions, the amount of agglomerated carbonates was about 12% for CTAB and 5% for DDAHCl.

Jan 1, 2014

By Q. J. Liu

The flotation circuit and the reagents of the all-sliming flotation about low grade and hard operation on zinc oxide ore are researched in the paper. The results indicated that there are many types of zinc minerals in this ore, and the composition is very complex. They include hemimorphite, smithsonite, hydrozincite and so on. The ore is seriously sliming. In light of the ore properties, three kinds of flowsheets have tested. They are gravity concentration (cleaning tables), flotation, combined process of gravity concentration and flotation. The test showed that the recovery of zinc is only 17.08% in the gravity separation. In combined process of gravity separation and flotation, the recovery of zinc concentrate is close to 70%. But the flow-sheet is complex and hard to control in the production. The floatation circuit is feasible. In the test, it pay attention to investigate the new combined reagent which is used in selective all?sliming flotation process. The effects of slime are eliminated by the multi-loop treatment of middling. In flotation, the final recovery of concentrate is 88.76%; the grade is 29.50%. The recovery of physical ore is 93%; and the recovery of -10mm fraction is more than 65%.

Jan 1, 2014

By Meylin Terrel-Gutierrez

El presente texto muestra un modelo cuasianalítico para predecir la SD (Sechi) en cuerpos de agua claros y turbios. El enfoque está basado en el la relación inversamente lineal entre la SD y las concentraciones de OAS, donde la última ha sido reemplazada por su banda de reflectancia correspondiente o sus combinaciones propuestas por estudios previos de acuerdo con el tipo de cuerpo de agua.

Jan 1, 2014

By A. G. Journel, CH. Huijbregts

"Centre de Morphologie MathématiqueSpecial problems arise in the evaluation of lateritic-type orebodies (Ni-Co, bauxite) or, more generally, orebodies affected by surface weathering. In this type of orebody, the vertical grade distribution shows, from the hangingwall downwards, a systematic increase followed sometimes by a certain decrease, or vice-versa. These trends appear together with irregular variations from one drill bole to the other.The problem is to characterize a vertical structure that is representative not only of the drill hole but of an entire panel or zone of influence, in order to define mineable thicknesses for given cut-off grades. The vertical grade distribution observed on the drillhole is replaced by a new curve, called 'derive' (drift), which is computed by 'universal kriging'.Once the vertical study is completed, new 'service-variables' are defined in the horizontal plane, such as mineable thickness and the corresponding average grade, economical functions (combination of the grades of several minerals). The local and global estimation of these variables can then be performed by a simple bi-dimensional kriging plan. The global estimation is summed up by several tonnage-cut-off grade curves.The practical valuation according to the above scheme of a New Caledonian lateritic nickel orebody is presented."

Jan 1, 2014

By M. Hopf

Numerous developments and improvements have been made to tap-hole designs. On the other hand, there are very specific designs in operation that have endured for many years without any modification. Nobody likes design changes because of risk - the risk of atypical wear, potential hazards, and costly repairs entailing enormous production losses. So the philosophy ‘never touch a running system’ is maintained, because among other things there is no efficient working monitoring technology for tap-holes. In the past few years a couple of new technical solutions have been investigated and developed. Not all theoretical solutions are possible in practice. However, metallurgists are inventive, and the last word regarding efficient working tap-hole monitoring technologies has not yet been spoken.

Jan 1, 2014

By C. Garcia, J. J. Opazo, A. Potulsha, T. Comi

"Sierra Gorda SCM is a joint venture partnership of KGHM International (owned by KGHM SA, Poland), Sumitomo Metal Mining and Sumitomo Corp. (Japan) operating in northern Chile. The Sierra Gorda openpit mine and coppermolybdenum processing plant will become one of the largest mines in the world. The need for optimum production efficiency and sustainability has driven the creation of the most modern, wellinstrumented mine in Chile. This article contains a general review of the project including geology and history.This was a fast-track project going from greenfield site acquisition to mill startup in 10 years. Highly experienced and motivated engineers and technical staff have overcome many significant challenges resulting in a rapid ramp-up of production capacity. A potential expansion to double the production rate in the fourth year of operation has also been intensely studied.The Sierra Gorda property is located in the Atacama Desert of northern Chile, in the District of Sierra Gorda, Region II of Antofagasta, Chile (Fig. 1). There is almost no precipitation in this area. The mine site is generally flat with some rolling hills. The project is located about 5 km (3 miles) from the village of Sierra Gorda at an elevation of approximately 1,700 m (5,600 ft) above mean sea level. The village is near a highway and railway line. The city of Calama, home of the famous Chuquicamata Mine, is located about 60 km (37 miles) northeast of Sierra Gorda. In addition, the SG mine is in the midst of numerous other mines including Spence, Esperanza, Mantos Blancos, El Tesoro, Lomas Bayas, Gabriela Mistral, El Abra, Radomiro Tomic and Escondida, to name a few.The primary organizational value at Sierra Gorda is "Zero Harm." This includes employees, contractors, the environment, the community, plant facilities and mine equipment. A cornerstone of this program is called 5X5S (five by five S), which combines the lean principles of 5S with the safety model of taking five steps back and thinking about the task at hand for five seconds, five minutes, the time it takes to assess and manage the risk. "People caring about people" promotes proactive engagement in the safety of coworkers and others at work and at home."

Jan 1, 2014

By Carlos M. Fontes Vieira, Ruben J. Sanchez Rodriguez, Carlos E. Gomes Ribeiro

"In this study we attempted to model a response surface for the apparent dry density of ternary blends of calcitic marble particles. The crushed marble was divided into three granulometric ranges. Simplex network methodology was used to determine the mathematical relation between granulometric ranges and apparent dry density (ADD) of particle mixtures. A highly significant regression was obtained and the simplex network methodology proved to be able to predict high packing particle compositions.IntroductionProblems with packing and expected porosity of particles are common and widely recognized to be important in terms of both fundamental physics and engineering applications. For example, densification of a powder mass is important in the shaping of solids in ceramics, powder metallurgy or composite synthesis; chemical processes such as solid-liquid separation (sedimentation, thickening and filtration), raw material handling (stockpiling, blending, drying, storage and transportation) and pyrometallurgical processes (agglomeration, coke making, ore sintering, blast furnace iron making and new iron making processes) [1,2].Many factors can affect particle packing, but in practice, there are three main factors: (dimensionless) particle size distribution, particle shape and absolute particle size [2].Geometrical and practical methods were developed to predict properties in mixtures. Zou, Gan and Yu [2] present a paper treating a prediction of the porosity of multi-component mixtures of cohesive (fine) and non-cohesive (coarse) particles. Bahiense et al. [3,4] used a simplex network to determine a mathematical model for obtain the optimal compositions between aggregates to a greater packing of a ternary particles mixture. Despite these techniques for predicting particle packing, some studies in particulate composites production don't present clear criteria for choice of particle distribution [5,6]. As the best particle packaging depends on the size, distribution and shape of these particles, individual models can be constructed for specific combinations of these factors."

Jan 1, 2014

By A. F. Usov

A potential of electric pulse disintegration in benification used for primary deposits ores containing precious metals is shown. Of special significance is that PGM and gold grains, being highly plastic, are easily liberated and are not smeared on the disintegrated rock fragments surface. It al-lows gravity separation, which is less expensive and more efficient, to be used instead of chemical processing, which is expensive and environmentally faulty.

Jan 1, 2014

By S. N. Titkov

Flotation of halite?new, recently begun to be developed method of processing water-soluble minerals. In the paper the results of studies of the new directions of the application of halite flotation are represented. Studies on the flotation separation of halite and sylvite in the salt solutions of different composition, showed the possibility of the halite flotation realization not only in the carnallite brine (content of salts: MgCl2 25.5% ~ 26.0 %, chlorides of potassium and sodium 5.5% ~ 6.0%), but in the sylvinite brine, which contains 10.5% ~ 10.8% KCl and 20.5% ~ 21% NaCl. On the basis obtained results are carried out experiences on the halite flotation from samples of the converted products of sylvinite ores by flotation method and by the method of the electrostatic separation. It is shown that in all cases it is possible to accomplish effective and selective recovery of halite. The halite recovery into the foam product of flotation makes 80% ~ 90% with an increase in the content of KCl in the cell product of flotation in comparison with a composition of flotation feed: - from the product after the electrostatic separation of ore ? from 76% KCl to 95% ~ 97% KCl; - from the small fraction of ore (- 0.25 + 0 mm) ? from 30% KCl to 60% ~ 64% KCl; - from middlings (intermediate products) of sylvite flotation from 16% ~ 31% KCl to 45% ~ 80% KCl. An increase in the molecular weight of alkylmorpholines increases the selectivity of the flotation separation of halite and sylvite. Halite recovery from small size fraction of ore or/and middling of sylvite flotation with the sub-sequent joint filtration halite product and tails of sylvite flotation allows to reduce considerably expenses for manufacture potash chloride from Pilot-industrial tests for the first time confirmed the possibility of the effective halite flotation in the saturated solutions of chlorides of potassium and sodium (sylvinite brine).

Jan 1, 2014

By Alexandra Garcia

A measurement-based ground control management system, commonly employed in coal mines, has been successfully implemented in a UK potash mine operating at a depth of over 800 m. This system includes the routine deployment of telltales in roadways throughout the mine to mitigate against the risk of large-scale roof falls and the deployment of detailed ?design monitoring? instrumentation for ongoing design verification. The routine monitoring systems used in coal mines have not been, to date, commonly applied in potash mines, despite the similar, variable weak geology and associated ground control hazards. Monitoring information from the site indicates that telltales can be deployed to monitor roof conditions, with action levels based on differential rates of strain, as opposed to absolute movement.

Jan 1, 2014

By Anand Bhagwat

Surface control can prevent the falls of ground between primary roof support systems and rib support. Using existing industrial products, and adopting them for mining applications, has historically attained surface control in underground mining. However, the latest innovative solution, a revolutionary wire mesh product, is designed specifically for underground mining applications jointly by Bekaert and Orica. This knotted wire mesh, FlexKnot? 2500 and FlexKnot? 3500, uses smaller gauge, higher tensile strength wires, than a chain link fence or welded wire mesh. The higher tensile wire enables the mesh to achieve greater ultimate load-bearing capacity, with significantly lower overall weight. Test results, obtained at the National Institute for Occupational Safety & Health (NIOSH) Mine Roof Simulator facility, illustrate the comparisons of the new FlexKnot with traditional 8- and 10-gauge welded steel mesh. The FlexKnot is superior in deflection, load-bearing capacity, and stiffness?categories that are critical in achieving safer surface control. It also offers enhanced corrosion resistance because of the galvanized coating applied on the individual wires prior to the knotting process. Case studies from underground coal mine installations confirm that FlexKnot has the ability to significantly reduce installation cycle time and to minimize use and repetitive manual handling of individual mesh panels. An added advantage is the ability to supply FlexKnot in rolls for quick and easy handling for either rib or roof support application. When using rolls, the bolter can install the entire roll with one continuous forward motion, unlike the wasteful back and forth travel for mesh panel.

Jan 1, 2014

By L. C. Zhou

The floatability of andalusite and associated minerals are studied and their action mechanisms of andalusite and associated minerals with collector alkyl benzene sulphonate are also studied. Through the mensuration of electrical potential and the infrared spectroscopy, as well as desorption tests, it is confirmed that the interaction of andalusite with sodium dodecyl benzene sulphonate (SDBS), is in addition to physical adsorption, but also is chemical adsorption. The study results of the pure minerals are used for the flotation of actual andalusite mineral. By flotation from contain-ing 45.68% andalusite ore, the fine andalusite concentrate is gained which Andalusite grade is 85.88%, containing Al2O355.29% and Fe2O3 less than 1.5%.

Jan 1, 2014

By Darryel Boucher, Raymond Langlois, Neil Rowson, Kristian Waters

The Knelson Concentrator is a centrifugal gravity concentrator composed of a high speed rotating bowl into which a mineral slurry is fed. The rotational motion creates a centrifugal acceleration up to an equivalent of 200 G. Under this acceleration, particles enter fluidised riffles along the side of the bowl, with the fluidisation allowing for the substitution of dense material for less dense. The separation mechanism is not fully understood and questions remain on the optimal residence time, slurry feed parameters and bowl surface profile to achieve a better separation. The positron emission particle tracking (PEPT) technique has been applied to record the motion of a -1700+1180 µm particle of a quartz-gold matrix, labelled with 18F radioisotope while it undergoes concentration inside a 3" laboratory scale Knelson Concentrator (KC-MD3) operated at 60 G. The slurry used was composed of quartz and magnetite. Particle trajectories during the first stage of the concentration process where the heavier particles centrifuge through the increasingly dense slurry towards the riffles of the bowl are shown with respect to time. This work reveals new information on particle motion inside the Knelson Concentrator and the results will be used for validation of developed separation model as well as optimisation of a centrifugal concentrator’s performance.

Jan 1, 2014

The molybdenum ores currently utilized in China are mostly molybdenum sulfide ores whereas oxidized molybdenum ores, being finely disseminated and difficult to process, have not been exploited and utilized effectively. In this article the beneficiation process of a molybdenum ore occurred in an oxidized ore zone was investigated in order to provide a new way for the development and utilization of the oxidized molybdenum ores in China. The molybdenum mineral in the ore was mainly wulfenite and the associated minerals included barite, limonite, quartz and small amount of cerusite. Limonite in the ore occurred in a crust and honeycomb-like colloidal state and composed the framework for the formation of the other minerals in the ore, which filled the pores in the framework. Wulfenite was mainly fine-grained and occurred in the fine porous crust and honeycomb-like framework. The finely disseminated ore structure made the separation and recovery of the molybdenum mineral in the ore very difficult. On the basis of the mineralogical study of the ore, experiments were conducted to compare the various mineral processing methods for the beneficiation of the ore, including single gravity concentration, single magnetic separation, single flotation, and a combination of high intensity magnetic separation and gravity concentration. The results indicated that with single gravity concentration a molybdenum concentrate containing 5.85 % Mo with a yield of 11.76 % and a Mo recovery of 43.5 % was produced. With single high intensity magnetic separation it was very hard to obtain a molybdenum concentrate product. With single flotation process a molybdenum concentrate containing 7.06 % Mo with a yield of 15.14 % and a Mo recovery of 62.63 % was produced. With a combination of high intensity magnetic separation and gravity concentration a molybdenum concentrate containing 6.46 % Mo with a yield of 11.81 % and a Mo recovery of 42.11 % was produced. In conclusion, compared to the other methods the flotation process can produce more reasonable technological and economical results and is the best process for the exploitation and utilization of the finely disseminated oxidized molybdenum ore.

Jan 1, 2014

By Lala Zhao, Yuemin Zhao, Guangyuan Xie, Chusheng Liu, Chenlong Duan

"Screening is an important means of size classification used on granular or particulate materials. The vibrating modes of screen separator have a great effect on the screening process. Elliptical vibration mode is a complex motion mode which gets the common characteristics of both linear and circular vibration modes. However, the fundamental motion and screen penetration of the particles on the elliptically vibrating screen deck are still poorly understood. A numerical study of the motion of particulates flow along an elliptically vibrating screen deck is presented by means of a three dimensional Discrete Element Method (3D-DEM). The motion characteristic of the particle flow is analyzed at a particle scale. The effects of vibration amplitude, throwing index, vibration direction angle and screen deck inclination angle on the screening process are discussed. The results show that the particles average velocity increases linearly with the increase of vibration amplitude, throwing index and screen deck inclination angle, but decreases linearly with the increase of vibration direction angle. The screening efficiency is highest when the vibration amplitude, throwing index, vibration direction angle and screen deck inclination angle are 4.5 mm, 3.3, 40° and 6°, respectively. This work is helpful for developing a deep understanding of particle motion on the elliptically vibrating screen and for optimizing screen separator designs."

Jan 1, 2014