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By V. I. Ryaboy, V. P. Kretov, S. E. Levkovets, I. V. Ryaboy

"Using the flotation of a gold-containing ore from a deposit in Kazakhstan as an example, we have conducted a study designing dialkyldithiophosphate collectors, in addition to xanthates, for the flotation of hard-toenrich gold-containing ores to increase gold recovery.The increased flotational ability of the dialkyldithiophosphates was determined by their surface activity at the liquid-gas interface and their hydrophobic ability, the changing of which allowed us to control the collecting power and selective ability of the dialkyldithiophosphates. The studying of the surface activity of aqueous solutions was done using the stalagmometric method and the evaluation of the hydrophobic ability was done in percentage of the relative value of the zinc ion binding in the solution in standard conditions.Studying the influence of surface activity in our designed dialkyldithiophosphate collectors, with their close hydrophobic ability, showed that even with a small increase in surface activity in their aqueous solutions, gold recovery increased by 2-3% in laboratory conditions. Using this enabled us first to apply the dialkyldithiophosphate collector BTF-161 at a plant in Kazakhstan, and then to introduce the specially designed dialkyldithiophosphate collector BTF-163, which has been in use since. Further study of dialkyldithiophosphate activity based on this concept showed us that for the range of short-chain dialkyldithiophosphate collectors with a chain length of up to ?5, the effectiveness of ore processing became lower the higher their surface activity got, with relatively small differences in their hydrophobic ability. For long-chain dialkyldithiophosphates with a chain length of over ?5, ore processing effectiveness increased with the increase of their hydrophobic ability.Based on these studies, a new effective dialkyldithiophosphate collector, BTF-1517, was designed. Using this reagent in continuous gold recovery tests allowed us to reach an 84.21% recovery with a concentrate quality of 15.66 g/t, while using the applied collector BTF-163 in similar conditions led to the recovery of 82.87% with a concentrate quality of 15.65%. As a result, the Kazakhstan processing plant decided to conduct industrial tests with the BTF-1517 collector."

Jan 1, 2018

By Ghislain Bournival, Seher Ata, Yesenia Saavedra Moreno

"In froth flotation, frothers are commonly added to the pulp to modify the interfacial properties of bubbles. These properties may be modelled using commercial software packages. The volume of fluid (VOF) method was used to track the interface motion during the post-rupture oscillation of the newly formed bubble. The aim of this research was to provide an insight into the modelling of viscoelastic phenomena through the coalescence dynamics of two bubbles in solutions of various surface tensions using a three-dimensional computational study. Different surface tensions were used to simulate changes in methyl isobutyl carbinol (MIBC) concentration. The computational results were evaluated by comparing the oscillatory motion of the newly formed bubble for the different MIBC concentrations. For known MIBC concentrations, the deviations of the computational damping constants from the experiments were quantified, revealing possible deviations in the VOF surface tension model. In addition, the analysis provided insight into the flow patterns of the fluids and the effect of frother concentration on the velocity magnitude in the liquid and air phases. This analysis provided a further understanding of coalescence dynamic and post-rupture oscillation in froth flotation. Such a process is believed to affect the stability of particles at the interface due to the release of surface energy when the bubble surface is reduced.INTRODUCTIONIn froth flotation, bubble coalescence is an important phenomenon that is highly dependent on the interfacial properties of the liquid film between bubbles. It is known that the frother adsorption at the liquid-air interface changes the interfacial properties, resulting in an increase of surface elasticity and reduction of surface energy (Pugh, 2016). However, in a two-phase system, it is the frother type, concentration, frother molecule conformation at the interface and viscoelasticity properties that dictate film stability (Pugh, 2016). The viscoelasticity phenomena can be explained in terms of surface viscosity, which quantifies the energy dissipation at the interface and surface elasticity that represents the energy absorbed at the interface as result of bubble oscillation (Pugh, 2016). In the case of systems stabilized by nonionic frothers, it has been shown that surface forces alone do not account for film stability, but the viscoelasticity represents the ability to damp external disturbances in the thin film separating the bubbles and prevent coalescence (Santini et al., 2007)."

Jan 1, 2018

By Andreas Kaede

INTRODUCTION Due both to the political history of UNCLOS and the sensitivity of the ocean floor and environment to man made impacts, both the Convention (including also the 1994 Amendment) and subsequent codification (such as the ISA draft code on Exploitation of Mineral Resources in the Area) put a focus on information about, and conveyance of, technology employed by interested deepsea mining companies, to inter alia the Authority and developing countries. In contrast, companies usually are (or by their nature should be) interested in safeguarding their technology and business secrets in order to secure unique selling propositions in a competitive environment. On the background of the meanwhile maturing regulatory régimes on deep sea mining, the presentation will look into some of the key regulatory provisions mirroring these apparently antagonistic interests, how the players involved could deal with them, and how they might in some cases be reconciled. Progress of Presentation The presentation will start by briefly examining some classical methods of protection of technology, such as patents, copyrights, and (not the least) secrecy. It will be found that some of the statutory means of protection due to their territorial character may face problems in being implemented in areas outside national jurisdiction, such as the Area, but that, thinking globally, they nevertheless retain much of their value for the purpose of protection. Depending on available presentation time, a model case may be used to illustrate the above – and also some of the following – findings.

Jan 1, 2018

By M. Reza Saberi, T. Ted Miyake

Driven piles are a common tool in any engineer’s toolbox for supporting large structures over very soft ground, especially in high seismic risk zones. Challenges include achieving sufficient vertical and lateral load capacities within the constraints of pile spacing and geologic conditions. This was the case for a project in Orange County, California with a state-of-the-art, $180 million plant for biosolids processing, biogas management and energy recovery located in marshland next to an existing waste water treatment plant. The new construction for the Irvine Ranch Water District included a 70-foot (21 m) tall building and three closely spaced, 90-foot (27 m) high, 65-foot (20 m) diameter, egg-shaped steel digester tanks. The lower 35-feet (11 m) of the tanks were constructed below ground level. The site was underlain by up to 45 feet (14 m) of highly compressible peat and organic clays with standard penetration test (SPT) blows as low as 2 blows/ft (30 cm). Some of the peat layers had measured in-situ dry densities of less than 30 pcf (480 kg/m3) with moisture contents of over 250 percent. The soft clays and peat were underlain by a dense layer of sand and gravel at depth. Groundwater was very shallow. While nearby sites were designated by others as seismic site class “D”, this site was clearly class “F” (SF) which required site specific seismic hazard and time history analyses. Six recorded time histories were selected from the 1994 Northridge, 1989 Loma Prieta (California) and 1999 Chi Chi (Taiwan) earthquakes for the ground motion analysis considering the magnitude of the earthquake, distance to the source, characteristics of the earthquake source (i.e. type of fault displacement), peak ground acceleration, local site geology, station type (i.e. free-field or small structure stations), and spectral content that was similar to the period range of interest. Following ASCE’s Guideline Document 7-05, a site-specific horizontal acceleration response spectra (ARS) was developed for the maximum credible earthquake (MCE) associated with the site.

Jan 1, 2018

By S. Banisi, A. Ghasemi, S. Zare, F. Ghorbani, E. Nematollahi

"Comminution is the most energy intensive operation which constitutes the major portion of operating and capital costs of the mineral processing plants. Working at the maximum operating capacity of comminution equipment plays a significant role in the efficiency of the circuit. Appropriate design of cone crusher feed box could result in the choked crushing which is known as a vital factor in achieving target performance. In this research, the non-uniform cone crusher feeding at the Sarcheshmeh copper complex was studied and appropriate measures were taken to solve the problem. The problem resulted in non-uniform and high wear rate of crusher liners and high fluctuations of power draw. In recent decades, the discrete element method (DEM) has been applied successfully to study the effect of different factors on the behavior of particles flow. In this work, various designs for feed box were tested using an in-house developed DEM software called KMPCDEM©. The best feed box design obtained from the simulations was selected, constructed and installed in of the cone crushers. The new feed box design resulted in more uniform feed distribution on the distributor plate of crusher indicated by a reduction of the standard deviation of power draw measurements from 13 to 3 kWh. The better control of the crusher, 49% increase in the crusher throughput and finer and narrower product size distribution were the main outcomes of the installation of the new feed box. Furthermore, the wear rate on mantle and liners of crusher not only decreased but it also became uniform.INTRODUCTION Comminution is the most energy intensive operation which constitutes the major portion of operating and capital costs of the mineral processing plants. Reaching the maximum operating capacity in comminution equipment is a key sign of approaching the nominal productivity of the process. Due to the effect of crusher efficiency on the downstream circuit performance, optimization of the crushing circuits has received considerable attention (Herbst, & Potapov, 2004; Quist, & Evertsson, 2010; Li, Huiqi, McDowell, Glenn R, Lowndes and Ian, 2014; Cleary, Sinnott, Morrison, Cummins, & Delaney, 2017). Improving the performance of crushing circuits not only decreases the capital and operating costs but also increases the efficiency of downstream grinding circuits (Jacobson, Janssen, & Urbinatti, 2010). In cone crushers particles can be subjected to two different modes of compressive breakage; single particle breakage (free feeding) and inter-particle breakage (choked feeding). The maximum efficiency of the cone crusher directly depends on the type of feeding arrangement (Operation Manual, 1977). An appropriate feeding must lead to choked feeding the cone crusher. If the rate and method of feeding the crushers are correctly be executed, the maximum efficiency of the crushers could be available (Jacobson et al., 2010)."

Jan 1, 2018

By M. Kalicinski, M. Lyssyy

"Access to information is a key component for making improvements to any process. This is particularly true for all aspects of the iron mining and steelmaking process. The ability to make rapid control decisions can significantly influence process outcomes, including ensuring product specification, mining quality, transportation limits, upgrade factors, waste bypass and direct shipping, among many others. While traditional laboratory methods provide feedback for such processes, having access to analysis results in real-time can lead to positive reactive and predictive control decisions to be made rapidly, leading to significant improvements throughout the process. Scantech has been designing, manufacturing and supplying technological products to the minerals industry since 2002 to enable the availability of such real-time information to a mine or plant, with the benefits being enjoyed by a wide range of operators. This paper provides a summary of the available technologies used in the iron ore and steel industries, as well as providing case studies of their use in African and Australian iron ore and European steel, as well as a description of the potential benefits of a range of analysis equipment.INTRODUCTION Access to information is critical for any process, and is a fundamental component for making process control decisions. In order to yield effective processing outcomes, it is important for that information to be readily available, preferably as quickly as possible, and to be as accurate as possible. While speed and accuracy are often traded off against each other, there are numerous technologies available in a processing environment that allow for both rapid flow of information and a high level of accuracy. The use of on-belt analysis equipment has a long trusted history of use in a number of mining and processing environments and industries, providing information such as elemental composition and grade of conveyed materials, moisture content, waste proportion and energy information. Australian company Scantech has been a provider of such equipment since 1981, and has become an industry leader in both the supply and development of on-belt analysers across a range of industries."

Jan 1, 2018

By M. Saghaeian, R. Hejazi, M. Farahani, M. Dehghani, A. Tohry

"Wet tailing dams of iron ore processing plants typically contain a significant amount of valuable minerals. In more recent years, due to the increase in iron’s prices and technological innovations, as well as the low energy consumption which required for processing of materials from tailings, dams can consider as potential valuable deposits. However, the production of iron concentrate from tailings is usually complicated where the high moisture content of the material, the high clay content and the presence of chemicals of processing such as flocculants, acids and flotation reagents, all make materials highly sticky which can be easily swollen. In the present paper, the optimization of operational parameters to recover ultrafine hematite iron ore from the wet tailings dams of the Chador-malu iron ore mine was investigated. The optimization of operational parameters, showed that with modification of the washing unit components for slurry making, the challenge of constraints from feeding the plant could be overcome. To decrease the magnetite content in the tail stream of the medium intensity magnetic separation (MIMS) and subsequently increase the efficiency, the orifice of the cleaner tail flow exit pipe was changed from 7 inches to 3 inch and yoke angle changed from 14 to 8 degrees. These changes increased mass yield by 3% and decreased the magnetite content in the final tailings to 1.2%. By recirculating the cleaner SLons of final tailings within the circuit, the solid percentage of the feed to rougher SLons decreased to around 15%, and as a result the matrices were not overloaded that easily, and mass yield increased to about 13% from 7%. All the above mentioned optimizations were achieved without significantly affecting the concentrate Fe grade."

Jan 1, 2018

By J. Raatikainen, I. Auranen

"INTRODUCTION Sorting technology has advanced rapidly recently. Of the two possibilities particle sorting has advanced especially in introducing new sensors and the use of multiple sensors. The analyzing and computing lead times have also shortened. This has made it a viable technology option for many applications but not for the most important sorting task at a mine; the run-of mine ore. Bulk sorting, however, has advanced in smaller steps, even if the technology has the capability to tackle the run-of-mine ore and offers a high potential to bring mines substantial economic benefits. The sensors, which are useful are restricted by the difficult operating conditions or by the ore characteristics. One of the important features of run-of-mine sorting technology is the major material handling infrastructure required. The capital expenditure can be substantial requiring good understanding of the sortability curve (grade-recovery curve) behavior of the ore. This paper discusses one industrial case, where substantial amount of data measured from the ore feed belt has been obtained. This data was then analyzed for the grade recovery curves obtainable from that ore with sorting. EXPERIMENTAL The XRF measurement used was the FCA device from IMA Engineering (Fig.1). It is a specially built version of XRF designed to operate with coarse material. The measurement was situated at the main belt conveyor taking ore from the primary crusher to the stockpile. The crushed ore was about 80% -300 mm at a capacity of 1100-1200 tph (Fig.2). Measurement times were varied from 30 seconds to a minute. Measurements were obtained over several months.As the XRF is a surface distribution measuring technique, the measurement was first tested upon accuracy and reproducibility against plant daily wet chemical assays and against on-line Courier feed analysis. As there is a varying delay in the ore stockpile, the delay time was used as a variant in the validation. Different measurement times were tested for accuracy. A one minute measurement time gave a total measurement relative standard error, which was both for Cu and Ni below 3%. The results showed also very robust correlations; for Cu, the correlation coefficient was R > 0,94 for one minute measurements over three months and R > 0,86 for Ni respectively. Fig 3. Shows a measurement period of two hours showing substantial feed grade variations (given as relative value; 1.0 represents the mean value during the measurement month)."

Jan 1, 2018

By A. M. Amdur, A. N. Matushkina, G. I. Gazaleeva

"The article highlights results of theoretical and practical studies on the enlargement of fine gold in the process of heat treatment. The object of research is refractory gold silicate-carbonate ores of Vorontsovskoe Deposit (Northern Ural), containing fine gold. For setting up experiments and analyzing the results were used the methods of applied mathematics, mathematical statistics, mathematical and physical modeling. Modeling and calculations were performed using the software package HSC Chemistry 6.0, MatLab, setting up a full factorial experiment and other modern modeling methods. Using a scanning electron microscope, the distribution of fine-dispersed ore gold particles by size was studied. It was found that gold particles smaller than 0,4 µm smoothed the vertices and edges, i.e. they are of globules with an amorphous structure. Amorphous materials are nonequilibrium phases with high thermodynamic activity. The physicochemical properties such as melting temperature, diffusion coefficients, the content of metal impurities differ from the properties of the solid phases. In the course of the research were formulated the following scientific bases of the mechanism of enlargement of the gold particles: - the movement of dispersed droplets of gold in the process of external heat to the surface of the ore particles in the pore occurs under the action of thermocapillary pressure; - after melting of the host rock occurs flotation of molten droplets by the bubbles of gases and coagulation of fine gold; - the conditions of flotation drops of gold in oxide melts; floated drops of radius R = 1-100 µm. Analysis of the equilibrium at the perimeter of wetting a drop of gold-oxide melt-gas showed that the scheme of the tension will not significantly differ from the case of solid gold, while the radius of the gas bubbles should be at least 2 times greater than the radius of drops of gold. The proposed method of predicting the results of the enrichment of the proposed scheme, including heat treatment and gravitational centrifugal concentration of crushed ore. Experimental verification of the proposed scheme in the laboratory showed a satisfactory convergence of experiment and prediction. Gold recovery in the concentrate was 33,84 against 33,7 percent forecast. The increase in overall gold recovery to a gravity concentrate after heat treatment is more than 20 %."

Jan 1, 2018

By Shi Shuaixing Zhang Yuejun, Fan Xuesai Zhangming

"For the traditional principle of flotation cell design, or in the perspective of some researchers, the mixing effect of impeller for flotation cell is not only to suspend the particles off the bottom, but also to mix slurry well to achieve a uniform system. But for some special processing conditions, the depth profile of slurry concentration and particle size demonstrates an obvious difference. In the part around of the impeller in the cell, the slurry concentration is much higher than the part below the lip.For the vanadium titano-magnetite flotation process, distinguished with high concentration and large coarse particle size fraction, even though the concentration is very high, it can reach good gas dispersion, which is a fundamental principle for flotation cell design and application. The gas dispersion is not a challenge in the high slurry concentration environment, not only in the vertical direction, but in the cross section. Different levels (the distance from the lip is 400mm, 700mm, 1200mm, 1700mm, 2200mm, 2700mm) slurry in the flotation cell is sampled and analyzed. The slurry concentration of the 3 levels(1700mm, 2200mm, 2700mm) is about 55%, but the slurry concentration decreases from 55% to 25% sharply towards the lip.Therefore, a new understanding and viewpoint is presented, that the uniform system of slurry is not always reasonable for all of the flotation process. For some special process, if the coarse particles are needed to agitated well and transported to the upper cell, the quiescent zone in the upper cell will be destroyed and enhance the detachment probability for the coarse particles. The difference of slurry concentration and particle size fraction benefits the air dispersion and coarse mineral particles recovery.1.INTRODUCTIONNowadays, flotation is the most widely used separation process in the mineral processing industry. The importance of flotation technology in the global economy is significant. A rough estimate of the quantity of crushed ore treated by flotation is about nine billion tons per year, and the portion of base metals processed using this method is approximately 95% (Brewis, 1996)."

Jan 1, 2018

By Takanori Kokubo, Kenta Suzuki, Tomohiro Sasaki, Toshiya Anami

"Previous work has shown that the strengthening Al-Mn alloys with copper leads to the formation of an undesirable reduction in recrystallized grain size. In this study the mechanisms of strengthening and recrystallization behavior in a continuously cast automotive heat exchanger fin stockof Al-1.1wt%Mn-0.5wt%Fe-0.3wt%Si with a0.3wt%Cu addition were investigated. Metallurgical analysis revealed that the Cu strengthening was dominated by the formation of dispersoid particles, while solid solution strengthening decreased with the Cu additions. This result is attributed to the decrease in the amount of Mn solid solution. The post brazing recrystallized grain size was reduced compared to that not containing Cu. It is postulated that the Cu addition leads to a decrease in the amount of Mn in solid solution which leads to a finer grain size. This effect is attributed to Mn in the aluminum matrix inhibiting boundary migration but allowing other grains to grow during heat treatment. The results are rationalized based on particle stimulated nucleation (PSN), wherein dispersoid particles are more likely to become active recrystallization nuclei during the heat treatment. The increase in the number of active dispersoid particles with Cu addition is correlated to the recrystallized grain structure.INTRODUCTIONImprovements in properties such as strength, braze ability and corrosion resistance in thermal fin stock alloys are all means to gain improved efficiency in heat exchangers particularly in automotive applications. While Al-Mn alloys dominate automotive heat exchanger fin stock alloy, even small chemical compositional changes can profoundly influence these properties (Kawaharaet al., 2004; Yoshino et al., 2009). The microstructure (particularly the grain size and shape) also plays a key role in determining the product performance and hence the thermo-mechanical processing (TMP) must also be considered. The casting method (typically conventional direct chill, DC, or continuous casting) significantly influences the properties in no small part due to the very different TMP routes that are used. Continuous casting is generally favored for fin stock applications as its higher cooling rate (which can be 2 to 3 orders of magnitude higher than DC casting) leads to finer as-solidified intermetallic particles and an increase in super-saturated solid solution elements (such as Mn)that are known to improve fin stock performance such as strength, braze ability(Okiet al., 2008)."

Jan 1, 2018

By J. Noll, C. DeGennaro, C. Zhou, J. Srednicki

"The personal dust monitor (PDM) (model PDM3700), as well as other electronic devices, can cause electromagnetic interference (EMI) which can disrupt the operation of some proximity detection systems (PDSs). A 15 cm (6 inch) minimum separation distance between the miner-wearable component (MWC) of the PDS and the electronic device usually avoids these disruptions, but due to the amount of equipment on a miner’s belt and the method of wearing the PDM in some situations, this distance can be difficult to always reliably maintain. Another method of reducing EMI effects is utilizing magnetic field shielding. The shielding capability of several different materials was investigated by surrounding the PDM with the material and quantifying the EMI. A copper mesh pouch reduced the EMI from a PDM3700, allowing a minimum separation distance of 10 cm (4 inches) instead of 15 cm (6 inches) as shown in a previous study for an unshielded PDM. A MU-metal box had a better shielding effectiveness, as it further reduced the minimum separation distance to less than 7 cm (2.8 inches). Shielding reduced the EMI of the PDM with MU-metal providing better results than the copper mesh. These materials may be beneficial for shielding individual components of the PDM or for constructing a shielded pouch. However, before the advantages of a shielded pouch can be determined, the effects of just the shielding material (metal) on the PDS needs to be quantified. INTRODUCTION According to statistics from the Mine Safety and Health Administration (MSHA), 43 miners have been fatally struck or pinned by a continuous mining machine (CMM) since 1984. In an effort to prevent future striking and pinning fatalities from occurring, proximity detection systems (PDSs) have been developed and are required on all operating CMMs in underground coal mines, with the exception of full-face CMMs, by 2018 (MSHA, 2015)."

Jan 1, 2018

By V. M. Bystritsky, M. G. Sapozhnikov, G. M. Nikitin, A. B. Sadovsky, Yu. N. Rogov

"At present kimberlite ore is processed in crushers or grinding rolls with subsequent grinding in wet mills down to a size of 0.2 mm. The basic disadvantage of the standard diamond processing technology is that crushing kimberlite ore can damage the most valuable large diamonds of few carats. Tagged neutron method offers a possible solution to this problem. It allows detecting diamond inside kimberlite ore without its disruption. The results of the tests of the neutron separator prototype carried out at the Lomonosov processing factory of PJSC Severalmaz are discussed. The possibility to detect the diamond in the rock whose size is 10 times larger than the size of the diamond is demonstrated.INTRODUCTION At present standard diamond processing technology implies disintegration of kimberlite ore in crushers or grinding rolls down to a size of 0.2 mm. It inevitably leads to high probability that large and most valuable diamonds could be damaged. The fraction of diamonds which lost integrity in the process of ore enrichment could be as large as 35-65% [1]. Tagged neutron method (TNM) [2] offers a possible solution to this problem. It allows detecting diamond inside kimberlite ore without its disruption. The main idea of the TNM is irradiation of an object by fast 14.1 MeV neutrons from binary nuclear reaction d + 3H ?4He + n (1) and detecting (tagging) the 4He (a-particle) that accompanies neutron. That gives possibility to determine direction of the neutron momentum. Those tagged neutrons irradiate kimberlite ore under investigation and produce gamma rays via inelastic scattering reactions with nuclei"

Jan 1, 2018

By A. Singh

"Considering the dominant role of fertilizers in global phosphate production, it is evident that with the ever increasing development in agriculture there will be a growing demand for phosphate beneficiation. With the rapid depletion of high quality reserves, investigations into more complex and lower grade ore bodies are required. The Minerals Processing Division at Mintek has been involved in process development and flowsheet design projects on phosphate resources since 2003. This paper will discuss the processes that Mintek has explored and employed to upgrade various phosphate ore bodies (>30% Phosphorous Pentoxide (P2O5)) in preparation for end user application. These are aimed at an improved understanding of ores in terms of their varying mineralogy and the development of appropriate process routes to meet product specification. OVERVIEW OF MINTEK Mintek is a state owned science council that undertakes R&D, consulting and sells products and services into the minerals beneficiation industry. Mintek has been in existence for 83 years with a current permanent staff complement of 750 of which 300 are professionals with a tertiary education. Being a non-profit organisation, the majority of funding comes from state grant and earmarked funding. All research is needs-driven exploring innovation through technology and process optimisation trends. Owing to a solid base of expertise, extensive laboratory and pilot facilities, and a historical database of knowledge, Mintek is well positioned and equipped to execute projects on a scoping, feasibility, prefeasibility and bankable level. USES OF PHOSPHATE Phosphate is the component in fertilizer essential for root and stem development in plants as well as rejuvenation of harshly depleted soil for which there is no agricultural substitute. Phosphate rock is essential for global food security with 87% used in the production of fertilizers. In agriculture as fertilizer, phosphate is one of the three primary plant nutrients in addition to nitrogen and potassium. In former times, it was simply crushed and used as is, but the crude form is now only used in organic farming. Normally it is chemically treated to make Single superphosphate (SSP), Triple superphosphate (TSP), or Mono-ammonium phosphates (MAP) and Di-ammonium phosphates (DAP), which has a higher concentration of phosphate and is more soluble, thus more suitable for plant absorption."

Jan 1, 2018

By A. Y. Senchenko, S. G. Rybkin, A. V. Aksenov

"Oxidized nickel ores are important source for nickel production in Russia. Considerable explored reserves of oxidized nickel ores with relatively low nickel content, about 0.6-1.4%, are concentrated in the Ural region of Russia. Conventional process flowsheet with the use of blast matte smelting, applied in particularly by JSC “Ufaleynickel”, proves itself as extremely low-margin technology. This paper will examine development of a new more cost-efficient process involving integrated treatment of oxidized nickel ores using the ore from Serovskoye deposit as an example. Target products of this process are hydrate residues containing up to 15 % of nickel and 0.3 % of cobalt, as well as saleable salts of magnesium sulphate and ammonium suplphate. This innovative process includes roasting of a mixture composed of ground ore and sulphuric acid at 650 °?. Sulphate roasted product is then leached in a weak sulphuric acid solution with the following separation of liquid from insoluble solids. Sulphate solution is neutralized by aqua ammonia in two stages until media pH is 3.0-3.5 and 7.5-8.0 with detachment of iron- and nickel-bearing hydrate residues respectively. The mother solution is boiled out resulting in salt crystals which are then dried and roasted at 500-600 °? to obtain magnesium sulphate. The gases generated during salts roasting are captured with production of ammonium sulphate. The developed technology demonstrates higher potential in terms of its economics and eco-efficiency comparing with the conventional process. This innovative technology for integrated process of oxidized nickel ores was patented in Russia.INTRODUCTION Development and industrial implementation of efficient technologies to process oxidized nickel ores is a very important task for non-ferrous metallurgy of Russia. The main reasons for the required technical upgrade of the plants processing oxidized nickel ores is depletion of rich ores, increase of energy resources costs, amplification of environmental and production standards. Due to this, transition from conventional pyrometallurgy to cost-effective hydrometallurgical technologies of ore liberation and solutions processing is logical and corresponds to the worldwide practice of Ni production from oxidized nickel ores."

Jan 1, 2018

"The Circular Economy (CE) will play an important role in shaping a resource-efficient society. Enabling this transformation from a linear to a CE requires precise quantification of resource efficiency and thus the economic viability of the system. Based on the development of simulation tools of classical minerals processing and process metallurgy, the Outotec (2018) HSC simulation platform could be further developed (gleaning from many academically published works of the author listed below), permitting the simulation of the CE system and to subsequently calculate its resource efficiency. It enables the estimation of a simulation-based Recycling Index (RI) from a product’s Bill of Material (BoM) and Full Material Declaration (FMD). It is a unique methodology for Design for Recycling (DfR) based on minerals engineering linked to a deep understanding of minerals and metallurgical process engineering. A key to this simulation is a detailed understanding of the mineralogy (both geological and designed) of the CE system and its many products, materials and systems, both in a geological mineral and a product-designer-mineral sense. In addition, a detailed understanding and quantification of the thermodynamic properties of the system (both energy and exergy/entropy) is key to understanding its economics and its limitations. With this approach, the actual losses of the CE system are shown and thus highlights the limits of the CE as defined by minerals and metallurgical process engineering principles. INTRODUCTION From the dawn of the industrial era up to today, many of our products have been created according to the principles of a linear economy: we find resources, make a product, and then dispose of it when we are done using it. But in recent years, there has been a growing awareness of the need to move to a Circular Economy (CE), an approach that aims to maximize the usefulness of products, components and materials across the entire lifecycle. In terms of recycling, this means achieving maximum recovery of materials once products reach the end of their usable life while also maximizing resource efficiency. Of importance is therefore also not only the recovery of critical technology elements that make the CE system run, but also the criticality of the metallurgical infrastructure that must be present to recover these elements economically. Ellen Macarthur (2017) defines the CE as “Looking beyond the current ""take, make and dispose” extractive industrial model, the circular economy is restorative and regenerative by design. Relying on system-wide innovation, it aims to redefine products and services to design waste out, while minimising negative impacts. Underpinned by a transition to renewable energy sources, the circular model builds economic, natural and social capital.” However, when translating this significant message to images, it is striking that the key extractive industry is not depicted in the Ellen Macarthur as well as EU depiction of a CE (EU 2015). Other CE discussions are also wanting in their fundamental detail and description e.g. Accenture (2015) and Beaulieu et al. (2016)."

Jan 1, 2018

By J. A. Rusnak, K. M. Mohamed, M. A. Van Dyke, M. M. Sears, G. Rashed

"Researchers from the National Institute for Occupational Safety and Health (NIOSH) recently developed a coal-mass model to realistically simulate the deformation and loading behaviors of the ribs of coal pillars in underground coal mines. The scale-dependent properties (stiffness and strength) of coal material were considered in the coal-mass model. In this paper the orientation of face cleat with respect to driving direction was integrated in the coal-mass model. The controlling parameters (dimensionless coal-mass scale and fracture strains) of the modified coal-mass model were calibrated using a published case study of coal pillar strength. Numerical models with wide ranges of controlling parameters were conducted to simulate the test pillar. The best match between the numerical modeling results and the measured stresses and deformations was achieved by using a coal-mass scale of 30 and fracture plastic shear and tensile strains of 3.25% and 0.325 %, respectively. INTRODUCTION The failure of coal pillar ribs by itself are a major hazard in underground coal mines. Furthermore, failing ribs can indirectly contribute to roof and floor instability by increasing opening widths across intersections and entryways. Over the past decade, rib failures have resulted in 12 fatalities, representing 28% of the ground-fall fatalities in U.S. underground coal mines. Mining depth has always played a very important role in assessing rib stability. Gauna and Mark (2010) completed an analysis of rib fatalities that occurred between 1996 and 2010. One of their most prominent and influential findings was the identification of a relationship among fatalities, depth, and mining height. Therefore, Coal rib stability will continue to be a challenge for future deeper mines in U.S. coal basins. In the past several decades, research efforts have focused on roof support. The current rib control practice in U.S. coal mines is to select rib bolts through a trial-and-error approach (Mohamed et al., 2015a). Rib failure incidents can be can be substantially reduced or even eliminated by adopting an engineering-based coal rib design approach. The factors affecting rib stability in coal mines are numerous and mutually dependent. These factors include but not limited to mining height and overburden depth, interburden thickness for multiple-seam mining, coal strength, cleat density, entry direction with respect to cleat orientation, existence or absence of partings in the coal, percentage of extracted roof and/or floor rock, density of rib bolt support (Mohamed et al., 2015a). Moreover, it is difficult to isolate the particular effect of a specific factor on the overall rib stability. Therefore, a reliable empirical rib design approach is not achievable because it requires a significant number of case histories to be collected in order to have a reasonable range of all of the critical parameters. However, numerical modeling can be a practical tool to assist with rib support design if the modeling is realistic, which can only be achieved through calibration and validation of the numerical model against field data."

Jan 1, 2018

By A. R. Videla, P. R. Brito-Parada, I. Mackay

"Linking results from laboratory scale experiments to industrial flotation behaviour is challenging. Typically, such experiments involve batch tests in which the system does not operate at steady-state, making it difficult to infer the effects that operating conditions have on flotation performance. In order to overcome this limitation a 4-litre recirculating tank was previously developed at Imperial College London. This tank is capable of reaching, and operating at, steady-state by recycling overflowing concentrate back into the feed. As well as instruments to control operating conditions, it is fitted with a system of sensors that allow the surface of the froth to be dynamically monitored. From this information, it is possible to measure the air recovery—a proxy for froth stability. Thus, this bench-scale tank can be used to understand the effect of differing operating conditions on flotation performance at steady state. However, so far, this cell has only been used to investigate idealised systems with only one or two species.Reprocessing of tailings dams is not only environmentally desirable but also increasingly economically feasible due to the declining head grades of primary deposits. There is also the added benefit of no further milling being required prior to flotation. However, the effects of fine and ultrafine particles on froth stability are not yet fully understood. In this work, the bench-scale continuous tank has been used for the first time to determine the flotation response of a complex feed, consisting of samples from a copper tailings dam, to changes in operating conditions. It was shown that the froth stability in the system is comparable to that of previous work and industrial tests, with a peak in air recovery being found at a superficial gas velocity of 1.13 cm/s. There is scope to optimize the froth stability of tailings flotation for enhanced metallurgical performance."

Jan 1, 2018

By M. Scaggs, K. Phillips

"Coal Worker’s Pneumoconiosis (CWP) is an occupational lung disease caused by chronic exposure to respirable mine dust. After decades of steady decline, CWP incidence appears to be on the rise since the mid-1990s, particularly in some regions of Appalachia. Alarmingly, many of these cases have rapidly progressed to the most advanced form of CWP, referred to as Progressive Massive Fibrosis (PMF). Most of what is currently understood about respirable mine dust has been gleaned from routine regulatory monitoring, which tracks total mass concentration of respirable dust (mg/m3) and, less frequently, silica mass content. This paper focuses on the use of thermogravimetric analysis (TGA) as a way to provide basic characterization of the whole composition of the dust, allowing it to be classified into three mass fractions – coal, carbonate, and non-carbonate minerals. TGA was conducted on 59 dust samples collected by miners from eight coal mines in central Appalachia, and the results are discussed in terms of differences between mines, regions, and primary occupations. Consistent with prior results on area dust samples from some of the same mines, results of the personal samples generally show that the coal mass fraction of the dust is relatively low. Carbonate and non-carbonate minerals thus tend to make up the bulk of the dust mass, and vary across occupations and specific mines. INTRODUCTION After nearly four decades of decline, the prevalence of Coal Workers’ Pneumoconiosis (CWP, or “black lung”) in the US has been on the rise since the mid-1990s (Laney et al., 2014; Laney et al., 2010; Suarthana et al., 2011; Pollock et al., 2010; Antao et al., 2005; Blackley et al., 2016). Particularly alarming is the number of cases of progressive massive fibrosis (PMF), which is the most advanced form of the disease (Pollock et al., 2010; Antao et al., 2005; Blackley et al., 2016; Laney et al., 2017). A recent study by Laney et al. (2017) observed 192 US coal miners participating in the Coal Workers’ Health Surveillance Program (CWHSP) who had been diagnosed with PMF since 2000. Of the 163 (85%) that had a normal radiograph on file to use as a baseline, 27 (17%) of these individuals had progressed from a normal radiograph to PMF diagnosis in less than 10 years. Moreover, 162 (84%) of the individuals in that study worked in KY, WV or VA, and 169 (88%) had only ever mined underground. Blackley et al. (2016) also reported on a group of 60 PMF cases that were discovered by a single black lung clinic in eastern KY. Since seeking care at such clinics and participation in the CWHSP are voluntary, and could be influenced by a number of factors, these recent reports may well overestimate the degree of resurgence in severe disease (i.e., versus disease that was previously under-reported). Even so, they highlight a critical need to better understand the cause(s) of disease development and progression – such that effective interventions can be devised."

Jan 1, 2018

By Rolf B. Pedersen, Filipa Marques

The extension of the Mid-Atlantic Ridge north of Iceland has collectively been referred to as the Arctic Mid-Ocean Ridges (AMOR). The AMOR extends from the northern shelf of Iceland, to the Siberian shelf in the Laptev Sea, passing en route through the Norwegian- Greenland Sea, the narrow gateway of the Fram Strait, and across the Eurasia Basin. The AMOR is 4000 km long and is divided into six super segments: 1) the Kolbeinsey Ridge, 2) the Mohns Ridge, 3) the Knipovich Ridge, 4) the Molloy Ridge, 5) the Lena Trough, and 6) the Gakkel Ridge. After continental rifting at 60-50 million years ago, around 2.5 million km2 of oceanic seafloor has formed by seafloor spreading - resulting in the formation of the Norwegian- Greenland Sea and the Eurasian Basin. This northernmost part of the global ridge system is anomalous in several ways: The seafloor spreading takes place at an ultraslow rate (less than 2 cm/y) with spreading rates decreasing northward to around 1 cm/y at the Gakkel Ridge - which is the most slow-spreading ridge on Earth. As a result, the volcanic activity along the northern part of the AMOR is low, the oceanic crust is unusually thin (around 3,5 km at the Knipovich Ridge, Kandilarov et al.2010), and the rift valley is deep (average water depth > 3 km). In the southern part of the AMOR, the ridge system is affected by the Icelandic plume and a hot spot below Jan Mayen. The ridge-plume interaction results in higher volcanic productivity, unusually thick oceanic crust (9-11 km, Kandilarov et al. 2012) and shallow ridge segments (1500-100 m). The AMOR also display contrasting spreading regimes, whereas some super segments are dominated by orthogonal spreading (Kolbeinsey and Gakkel Ridge) others are characterized by highly oblique spreading (Mohns and Knipovich ridges). Some ridge segment displays asymmetric spreading, like the Mohns Ridge where core complexes preferentially form along the northwestern flank. Together these variations in ridge characteristics results in large diversity of hydrothermal systems and associated mineral deposits.

Jan 1, 2018