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By J. L. Collins

"Une recherche debutee en 1987 tente de cerner divers éléments ayant un impact sur la productivite miniére, de facon à améliorer la planification des operations souterraines. II a été possible de recueillir jusqu'à trente variables dans sept opérations minières differentes du Nord-Ouest québécois. Cette présentation rend compte de quelques résultats préliminaires obtenus à l’une d'entre elle. Entre autres, elle montre comment une association entre une analyse de régression multiple et un logiciel d'optimisation (OPTIMUL) peut servir à une application particulière de la planification d'une opération minière du Québec. Plus spécifiquement, la présentation montre comment une quantité appropriée de ANFO et de TOVEX peut maximiser la quantilé de minerai cassé, minimiser les couts de sautage ou encore minimiser les coûts d'explosifs par tonne de roche cassée, en se basant sur une série de contraintes réalistes provenant de la mine.ABSTRACTA study, underway since 1987, tries to evaluate factors affecting mines' productivity. Information has been collected from seven underground mines in Quebec and this paper shows preliminary results from one. In particular, it shows how a combination of multiple regression analysis, mathematical programming and a set of realistic mine constraints can be used for a particular application of mine planning. More specifically, the paper shows a parallel between maximizing production of tons of broken are, minimizing explosives costs or minimizing the costs of explosives per ton of broken are by an appropriate selection of ANFO and TOVEX quantity of explosives. Finally, the paper shows that minimizing the costs of explosives per ton of broken are is the best alternative to follow providing a special optimization program can be set up."

Jan 1, 1990

By Donald J. Hallbom

"While pipeline hydrotransport is often the most economical way to transport large volumes of mineral concentrate, tailings, or fine ore slurry over long distances, it is in mountainous terrain that pipelining becomes particularly attractive. These areas are often remote, with limited existing infrastructure and few potential users willing to share in the cost of new infrastructure. The rugged terrain makes the construction of railways or roads suitable for haul trucks difficult and expensive. The elevation difference between the mine and the terminal means that the empty trains or haul trucks need to return up-hill, resulting in high fuel costs. With pipelines, this elevation difference may reduce or even eliminate the need for pumping. As a result, numerous pipelines have been built, or are being considered, in mountainous regions around the world including: Tasmania, New Guinea, China, Madagascar, the Rockies of North America, and the Andes of South America. However, there are technical difficulties that need to be overcome in the design and operation of mountain pipelines that do not affect pipelines on more level terrain. This presentation reviews some of these difficulties and methods used to overcome them.INTRODUCTIONPipeline transport of solid-liquid slurry (“hydrotransport”) is an important and cost-effective means of transporting large volumes of solids over long distances, especially from a single supplier to a single user (e.g., a concentrator to a port, a concentrator to a tailings dam, or a coal mine to a power plant). Pipelines are generally found to be more economically attractive than alternate transportation methods (e.g. trucking, rail, conveyors, shipping, or some combination) over the life of a project (Aude et al. 1974).Hydrotransport systems have been built in a variety of terrains, but it is in mountainous regions that pipelining becomes particularly attractive. These regions are often remote and generally do not have existing transportation infrastructure (roads, railways, navigable rivers). There are few potential users (e.g., farmers, other mines, forestry companies, etc.) who may be willing to share in the cost of new infrastructure. The rugged terrain makes the construction and maintenance of railways or all weather roads suitable for large haul trucks difficult and expensive. Mines tend to be higher than the receiving terminal (e.g. a port). This means that the empty trains or haul trucks need to return up-hill, resulting in high fuel costs. With pipelines, this elevation difference may reduce or even eliminate the need for pumping. Pipelines are easier to construct than roads and railroads in these areas for several reasons, including:"

Jan 1, 2006

By Garnsey R. G T, Wenk G. J, Toop A, Sowerby B. D

A bulk mineral analyser (BMA) suitable for the determination of Cu or Ni in bulk ore samples has been developed at the Lucas Heights Research Laboratories. This analyser, which uses the nuclear resonance scattering technique, is highly specific to the wanted element. The technique has previously been extensively field tested for copper at Mount Isa, Queensland.The present paper discusses the field trial in 1982 of a commercial prototype BMA for nickel. The trial was undertaken at the lateritic nickel mine at Greenvale, Queensland. The BMA and its shielding, together with a laboratory spectrum analyser, were sited in the sample shed adjacent to the workings. Two hundred and thirty-eight ore samples taken directly from the mine blastholes were assayed by the BMA. The average mass of sample was 12 kg, metal contents varied from 0.2 to 3.5 wt/per cent Ni and 4 to 43 wt/per cent Fe and free moisture varied from 11 to 55 wt/per cent. A measurement took 10 min to complete, although this time could have been reduced at the higher nickel grades. The r.m.s. deviation between BMA and chemical assays was 0.09 wt/per cent nickel. Iron and bulk density were also determined by the BMA, r.m.s. deviations being 1.7 wt/per cent and 0.03 g/cmJ respectively. Similar results could be expected from a BMA in routine industrial use at other nickel mines.

Jan 1, 1983

By S M. Iveson, K P. Galvin, D Kumar

Dry separation of iron ore fines and other heavy minerals has previously been achieved using one of two main approaches. The first is an inclined table with an upward airflow via small holes to help form an autogenous dense medium. The second is based on fluidised beds comprising a dense medium formed by fine particles suspended in an upward flow of air. In either case, vibration can be introduced. This paper describes recent findings using a novel system referred to as the Sink-Hole Fluidiser, which utilises elements of both these two former approaches. This device consists of a conventional gas-fluidised bed of fine medium with a 1 mm aperture mesh located at the surface. This mesh contains relatively large holes that act as sink-holes. The fluidised media flows upwards through the sink-holes and then falls back into the fluidised bed via the fine apertures in the mesh. The particles being separated, which are much larger than the fine media, pass over these sink-holes, where they either sink or float. The sink-holes offer a more precise balance of forces, applied on a single particle basis, resulting in robust density separation.Experiments have been performed using 2.0–4.0 mm tracer particles of density varying from 2.4 to 4.8 relative densities (RD) separated in a 200 mm diameter Sink-Hole Fluidiser with a single 13 mm diameter centrally-located sink-hole. In this preliminary semi-batch work, it was found that the Sink-Hole Fluidiser was able to achieve sharp separations (Ep as low as 0.20). This work underpins the development of a new continuous steady-state Sink-Hole Fluidiser, applicable to the dry separation of iron ore fines.CITATION:Kumar, D, Iveson, S M and Galvin, K P, 2017. A novel sink-hole fluidisation method for dry separation of iron ore fines, in Proceedings Iron Ore 2017, pp 221–226 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By Gartrell H. W

During investigations of the treatment methods for ore from the Bird-in-Hand gold mine carried out at Kalgoorlie and at these laboratories, it was found that excess alkali caused a lowering of extraction by cyanide, the cause of this being attrIbuted to the presence of a small amount of oxidised lead compounds in the ore. The subject has been discussed by various writers,3 but no satisfactory explanation of existing facts has been put forward. The experiments described in this report have been carried out with the object of obtaining some insight into the chemical reactions underlying the effect of lead salts and alkalis in cyanidation.The formation of cyanide-insoluble coatings on gold during roasting with lead compounds is well known, but the adverse effect of alkalis in cyanidation of ore is *This paper represents work done under a co-operative agreement between the Commonwealth Council for Scientific and Industrial Research and the South Australian School of Mines and Industries.Published by permission of the Mining Advisory Committee, Commonwealth Council for Scientific and Industrial Research.

Jan 1, 1935

By S. K. Mitterecker, T. Hofbauer, F. Baerhold

"Acid regeneration is a very important process step in each acid leach circuit. It is required to recover dissolved metals and HCl from spent leaching acid. Andritz Metals presents its recently commissioned spray roast pilot plant. The facility is now available for testing and demonstrating acid recovery or metal oxide production which is a requirement in several flow sheets under development for the mining and specialized oxides industries. Results from pilot test campaigns are reported here. We are currently focusing on a nickel ore leaching process, which requires both a feasible iron control and acid regeneration step. In addition, we disclose the results of a magnesium ore and aluminium recycling test campaign conducted in our pilot plant facility.INTRODUCTION Hydrochloric acid regeneration is widely used in the steel industry to regenerate spent pickle liquors into hydrochloric acid at a typical concentration of 18 wt.%. Andritz Metals (formerly known as Ruthner) has built more than 200 acid regeneration plants worldwide (Andritz Metals brochure). As technology leaders Andritz also has vast experience with specialty metal oxide plants, producing metal oxides such as aluminium oxide (Al2O3), magnesium oxide (MgO), nickel oxide (NiO), cobalt oxide (Co3O4) and mixed oxides from metal chloride solutions (Baerhold F., Lebl A., Starcevic J., 2006), (Jedlicka, H., n.d.), (Ruthner M.J., Krischner H., 1973), (Ruthner Ind. Planungs AG, 1967). Hydrochloric acid leach circuits have been developed and proven in the industry for many years. Examples of industrial applications are: synthetic rutile production (TiO2) (Walpole E.A., Winter J.D., 2002), Quebec Iron and Titanium’s UGS process (Patoine M.-C., De Mori A., Borowiec K., Coscia C., 2002), magnesium and potassium production (Priemer H., 1973) and Goro Nickel (Vahed A., Colton D.F., Duterque J.P., Karner W., Baerhold F., 2004), (Taylor A., 2013). One of the critical process steps in developing a hydrometallurgical process is acid regeneration, as it is an economic requirement to recover both the dissolved metals and acid (commonly HCl) from the spent leaching solution."

Jan 1, 2016

The re-use of waste water from coal preparation plant tailings is always desirable, but is generally problematic in terms of solid-liquid separation. Dewatering and disposal of coal slurry at a high percentage of moisture poses a major technological and environmental challenge to mining and mineral processing industries world-wide. Characterization and flocculation of these coal tailings reveals that the separation of fine coal tailings depends on factors such as size distribution, slurry viscosity, zeta potential, pulp density, circuit design, plant operating parameters, and the behaviour of solid particles in an aqueous medium. The present study was carried out on -600 mm coal tailings collected from a coking coal preparation plant of Jharia Coalfield, India, using anionic flocculent. Characterization studies revealed that the zeta potential was highest (-44 mV) at a pH of 9.0, the size range of the particles was 1.1?700 m, and the average ash content was 62.57%. Flocculation studies were performed at different solid concentrations, pH values, and polymer dosages. The results indicated an efficient settling rate of 178.15 mm/min at 8% solid (w/w) at a flocculent dosage of 32.50 g/t solid. The turbidity of the clear liquid obtained was 7.42 NTU.

Jan 1, 2014

By James McKelvey, Larry Drolet, Jason Swartz

INTRODUCTION When divers discovered that sections of a tunnel housing the pipeline that conveys wastewater from the Charleston Peninsula to the Plum Island Wastewater Treatment Facility had caved in, the Charleston Commissioners of Public Works(CPW) moved quickly to determine a long term solution for the city’s collection system, immediately focusing on the Ashley River sewer tunnel along the western boundary of the peninsula. Working with the Charleston community, as well as federal, state, and local officials, CPW developed a fast track yet long life design that can be used as a model for underground construction of tunnels in urban areas. The paper that follows summarizes key aspects of the Ashley River sewer tunnel project. HISTORICAL CHARLESTON Charleston, South Carolina is a culturally significant and historic city that was originally settled in 1670. There are over 100 buildings on the National Register of Historic Places within the Charleston area. Additionally, the first shots of the American Civil War were fired at Fort Sumter in the Charleston Harbor in 1861. As one can imagine, tourism generates significant business for the area with over 1.5 million people visiting Charleston each year. No project, especially one that requires digging, is done within the old city on the Charleston peninsula without careful planning. Many precautions are necessary to prevent damage or disruption to the historical properties. The Ashley River sewer tunnel project is exclusively in the old city. A lot of work was done during the design phase to minimize the impact to historical properties. Some of this work included: an archeological study (where pre-digs were monitored at all shaft sites by an archeologist); a building/structure assessment study (where structures near a shaft site were completely surveyed and cataloged); and an environmental study.

Jan 1, 2005

By L. F. Ruppert, P. A. Freeman, R. C. Milici, S. J. Tewalt, L. J. Bragg

The U.S. Geological Survey has completed a dig-ital coal resource assessment of six of the top-producing coal beds and coal zones in the northern and central Appalachian Basin coal regions. These include the Pennsylvanian-aged Pittsburgh, Upper Freeport, Lower Kittanning, Fire Clay, Pond Creek, and Pocahontas No. 3 coal beds and coal zones. Resources were calculated on all of the coalbeds/zones, with the exception of the Lower Kittanning coal bed. Preliminary original resources are estimated at about 93 billion short tons (84 billion tonnes), of which about 66 billion short tons (60billion tonnes) remain. Much of the remaining coal in all five coal beds/zones is thinner [<3.5 ft (1.07m)] and deeper [>1,000 ft (305 m)] than the coal that has been mined, but economic resources are still available and mining in each coal bed/zones will continue throughout this decade and into the next given current market conditions.

Jan 1, 2001

By J. W. Paul, J. N. Geyer

"GENERAL STATEMENTThe purpose of this report, which is the first of a series of three covering mines in the Fairmont district of West Virginia, is to give the result of a' study conducted in seal mines to ascertain the nature of the safeguards employed to prevent injury to the workmen from falls of roof and coal. In presenting the subject matter, consideration must necessarily be given to factors, features, and conditions such as method of mining, timber regulations and practices, supervision and natural conditions; and, for comparative purposes, a certain amount of statistical matter bearing upon the relation of fatalities and injuries to their causes, tonnage produced, men employed, days worked, and time lost.Those features and practices found to promote safe protection are summarized and suggestions made for such additional safeguards and practices as appear to give greater protection against injury from falls of roof or coal.ACKNOWLEDGMENTSThis study of falls of roof and coal in mines in Harrison County has been conducted by the U. S. Bureau of Mines in cooperation with R. M. Lambie, chief of the Mining Department of the State of West Virginia who assigned L. W. Brown, a district mine inspector, to assist in the field work and in the preparation of individual reports on each mine visited in this study. The writers acknowledge the helpful suggestions and cooperation given by these officials, the latter of whom assisted in the field work and prop red most of these sketches for the individual reports which wore submitted to the operator by the chief of the department. Thin report is a summary of the contents of the individual reports heretofore furnished the individual operator."

Aug 1, 1931

By S. Ilyas

Technical innovation in electrical and electronic equipment with new functions and design, stimulate consumer?s purchasing desire towards the latest equipments and this leads the rapid increase in the production of increased amount of waste materials Treason et al (2006) have reviewed the data on electronic waste generation in different parts of the world. Studies by Bertram et al (2002) have also affirmed that waste electrical and electronic components are the fastest growing waste category; this emphasizes the need for efficient recycling strategies. Recycling of electronic waste is an important subject not only from the point of waste treatment but also from the recovery aspect of valuable materials. However, recycling of electronic scrap is still quite limited due to the heterogeneity of the materials present in the products (Veit et al. 2005). A bioleaching based process offers a number of advantages compared to the conventional pyro or hydrometallurgical methods (Lee et al. 2007; Lee and Pandey, 2012). The advantages include simple, inexpensive (in some cases) and eco-friendly approach besides, generation of less active leach residue then other metallurgical processes. Though, biohydrometallurgical process has been successfully applied for the leaching of metals from ores (Olson et al. 2003; Rawling 2000), data pertaining to its application for the extraction of electronic scrap is still scanty. Recently, a few studies have been undertaken for extraction of metals from electronic scrap/printed circuit boards (Brandl et al. 2001; Faramarzi et al. 2004; Choi et al. 2004, Ilyas et al. 2007; Ilyas et al. 2010). These studies were conducted with mesophilic chemolithotrophic (Acidithiobacillus ferooxidans and Acidithiobacillus thiooxidans) or cyanogenic bacteria (Chromobacterium violaceum) or moderate thermophilic bacteria (Sulfobacillus thermosulfidooxidans). However, compared to bacterial leaching, fungal leaching has the following advantages: (i) ability to grow under higher pH, and thus is more suitable in bioleaching of alkaline solid waste (ii) a generally faster leaching process with shorter lag phase (iii) Chelation of excreted metabolites (e.g. organic acids) with metal ion, thus reduce its toxicity to the biomass (Burgstaller et al. 1993; Aung and Ting 2005). The specific objective of this work was to; ? Collection, isolation and enrichment of fungal strain ? Evaluate the abilities of Penicillium chrysogenum to leach metals from electronic scrap at various leaching modes (one-step bioleaching, two-step bioleaching, spent medium leaching, fresh medium leaching, leaching with deionised water and chemical leaching). ? Comparative study of all leaching modes

Feb 27, 2013

By Jaeheon Lee, Junmo Ahn, Jiajia Wu

In this project, low grade copper ore samples were obtained from two mining sites in the US, and they were chalcopyrite-rich (sample A) and conichalcite-rich (sample B) ore. Copper grades were 0.6% and 0.4% for the two samples, A and B, respectively. Leaching experiments were conducted by bottle roll tests for 24 hours, and various lixiviant systems were applied. Methanesulfonic acid (MSA) and glycine were used as alternative lixiviants to sulfuric acid. Oxidants including ferric ion and hydrogen peroxide were tested. The results showed the copper extraction of sample A increased after adding 1 g/L ferric ion in sulfuric acid and MSA solution, from 20% to 36%, but further increase was not observed with higher ferric ion concentration. The copper recovery increased significantly with H2O2 concentration, and over 80% copper recovery was obtained with 10% H2O2. For sample B, the copper dissolution kinetics were relatively fast and reached the maximum value in five hours. Around 60% copper were extracted in sulfuric acid and MSA solution. Copper recovery slightly increased after adding ferric ion and H2O2. Glycine is a weaker lixiviant for both samples, the copper extractions were 36% and 4% respectively. INTRODUCTION Chalcopyrite is the most abundant copper sulfide mineral on earth, and it is one of the most refractory copper minerals regarding chemical processing. The declining copper grade and depletion of copper oxide deposits stimulate the development of hydrometallurgical process to extract copper from chalcopyrite. The dissolution of chalcopyrite by ferric ion is normally illustrated as Equation (1) and (2) (Dutrizac & MacDonald, 1974): CuFeS2 + 4Fe3+ → Cu2+ + 5Fe2+ + 2S0 (1) CuFeS2 + 4Fe3+ + 3O2 + 2H2O → Cu2+ + 5Fe2+ + 2H2SO4 (2) However, slow kinetics are usually observed from chalcopyrite leaching at ambient temperature and pressure. Researchers attribute the slow kinetics to passivation during chalcopyrite dissolution, and different passivation products are also proposed (Klauber, 2008). In recent years, many efforts have made to develop new methods to extract copper from chalcopyrite, such as utilizing bacteria or stronger oxidant (Zhao et al., 2015; Ruiz-Sánchez & Lapidus, 2017).

Jan 1, 2019

By Vincent Jue

In December 2009, the Italian High Speed Rail Network AV began running over the full 1000 km system length from Turin, at the foothills of the Alps to Salerno, on the seacoast south of the volcano Mt. Vesuvius. It runs through Alpine rivers, highly seismic active zones, mountains, river plains, and through some of the most densely populated areas in Europe as well as some of its most expensive real estate. The Italian High Speed Network?s technical/economic constraints and its regulatory/socio-environmental concerns well may mirror similar obstacles set to confront the nascent California High Speed Rail Program. The two types of constraints must be dealt with together to reach the best construction solution. It is estimated that more than 20% of Italian High Speed Rail Network costs were spent on ground engineering including over 150 km of tunnels, 200 km of viaducts and bridges and 650 km of embankments and trenches. However, it also is estimated that 25% of costs were spent on social and environmental integration of the new rail lines including over 6 square miles of green offsets, 160 km of anti-noise walls, and 300 agreements for socio-environmental work. This paper will look at four examples of innovative ground engineering solutions, each with its own intricate set of constraints: ? Foundation system for viaducts across the ?Po? and ?Ticino? rivers. ? Soil consolidation under railway embankments ? Requirement of short tunnels for physical and environmental reasons ? Construction of railway stations in a confined right of way

Jan 1, 2010

By Joshua Micah Hoffman, Jhon Silva-Castro, Kylie Larson-Robl

A coal mine impoundment failure has the potential to be environmentally devastating and life-threatening. It is well documented that after seismic events slope failures in impoundments can occur. It has been concluded that often the main driven factor of the failure is the increase in excess pore pressure due to ground vibration. A small amount of research has been done regarding the stability of coal mine impoundments under natural seismic events; however no research has been done considering vibrations from mine blasts. If it is taken into account that current environmental restrictions oblige to increase the capacity of coal mine impoundments, thus increasing the hazard of such structures, it is necessary to evaluate the effects of near-by mine blasting on the stability of the coal mine impoundments in order to mitigate and control the potential of slope failures. To study the behavior of excess pore pressure under blasting conditions, scaled simulations of production blasting events were set up inside of a controlled sand tank. The research was divided in two stages. The first one was done, using dry conditions, while in the second part, the same set of tests were performed under saturated conditions. This document shows the partial results for stage one (dry conditions). For the tests, explosive charges were set off within the sand tank at various distances to simulate different blasting distances. Information was collected from geophones, accelerometers, microphones and high speed video camera for dry and saturated scenarios and additionally from piezometers under saturated conditions to assess the behavior of the material under blasting conditions.

Jan 1, 2015

By M Armstrong, S J. Coward, A Galli

Mine management is often expected to make rapid evaluation decisions at different stages of projects based on limited and uncertain data. The challenge is exacerbated by having to distil technical complexity into a financial model that is usually designed to produce only one or two key indicators, eg net present value (NPV), internal rate of return (IRR). Mining is a complex environment with many sources of uncertainty ranging from sampling to economics. In order to optimise investment decision-making, an appropriately structured evaluation framework must be utilised. An evaluation framework should be designed to encapsulate and integrate the complexity across the evaluation cycle, ie sampling, resource estimation, mine planning and treatment, and financial and economic modelling. This complexity is diverse and ranges from sampling support, scale effects to understanding the impact of variability, uncertainty and flexibility on operational efficiency and economic viability. These complexities, combined with time and capital constraints, usually do not allow all facets of evaluation to be integrated into the model. The model must strike a balance between simplified estimation techniques and sufficient incorporation of aspects of the project that will make a material difference to the investment decision. This paper demonstrates the impact of the scale of measurement on the valuation of a mineral project. Comparisons are made between global estimation averages using a top-down approach and local estimates using a bottom-up approach. Three sampling campaigns were conducted on a virtual orebody to compare the relative NPV accuracies. Stochastic forward models were run on foreign exchange rates and are compared with the results from a fixed foreign exchange rate model.

Jan 1, 2006

By T. Weatherwax

As part of a strategic research initiative at UBC to design and evaluate integrated underground mining and mineral processing systems, work has been done to determine how to utilize the coarse rejects of pre-concentration in the underground environment. An amenability study for nine orebodies from four of Xstrata Nickel?s Ontario operations evaluated both processing and waste disposal methods. The utilization of the rejects as a high quality backfill with minimal binder requirements has been identified as the preferred disposal method. Fill mixes utilizing the rejects in combination with classified tailings, full tailings, and cement were developed based on the geotechnical properties of the rejects. The mix designs were examined for both strength and rheological properties. The paper will present the results of the pre-concentration testwork, the design and strength testing of various mix designs for rejects from the nine ores and presents a conceptual design for an underground pre-concentration system based on this test work.

Jan 1, 2008

By NA UMC

Abstract Booklet

Dec 2, 2023

By K Kermanshahi, J Allen, MáHilden, M Powell, S Mwansa, S Palaniandy

Approximately 420 VertiMills« (VTM) have been installed in mineral processing plants throughout the world, mainly in tertiary and regrind applications plus several in secondary grinding duties. Metso Minerals (Metso) and the Julius Kruttschnitt Mineral Research Centre (JKMRC) have commenced a collaborative research program in stirred milling technology focusing on mill performance evaluation, model development and scale-up methodology. Industrial VTMs are being assessed using a consistent circuit survey protocol to evaluate the performance of VTMs in comminution circuits. The survey protocol includes identification and modification of sampling points, appropriate sampling techniques, controlled circuit stability, and best sample analysis practice. To initiate this study four surveys were conducted in the tertiary grind circuit in the Ridgeway Concentrator at Cadia Valley Operations (CVO) that treats the full circuit throughput of over 800 tph. To deal with the high feed rate the site opted to lead the world in the application of stirred mills by installing the largest VTM, at 3000 hp (2240kW) in closed circuit with a hydrocyclone bank. On average the operating work index was 13.1 kWh/t, reducing the secondary grind product by 40 - 50 ¦m to the required 80 to 100 ¦m range. The applied specific energy is relatively low in these low-intensity stirred media mills at 2.7 kWh/t. The size specific energy was 24.2 kWh/t-75¦m. Based on the survey and operating data the VTM circuit is performing well in this high-throughput tertiary grinding application, producing a sub-100¦m product.CITATION:Palaniandy, S, Powell, M, Hilden, M, Kermanshahi, K, Allen, J and Mwansa, S, 2013. VertiMill« - Development of circuit survey and performance evaluation protocols, in Proceedings MetPlant 2013 , pp 162-175 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

By F. Dehghani

The influence of different grinding methods on the shape characteristics of magnetite particles was investigated. Also, the effect of particle shape on the flotation of the magnetite, both alone and in the presence of quartz particles, was investigated. The shape characteristics of the magnetite particles were measured and calculated from images obtained by scanning electron microscopy via an image analysis system. The flotation tests were performed using a laboratory flotation cell. Results showed that in the -250+212 µm and -106+75 µm size fractions, ball mill products have a higher elongation value than rod mill products, while in the -150+125 µm size fraction, rod mill products have a higher elongation value. Particles with higher elongation values and lower roundness values have a higher flotation kinetic constant. Furthermore, the influence of magnetite particle shape on flotation is greater, and the flotation kinetic constant is higher, in the presence of quartz particles than in the flotation of magnetite alone Keywords shape, elongation value, flotation kinetics, magnetite.

Dec 1, 2013

By C. Vipulanandan

It is critical to monitor the ground conditions during excavation and drilling of boreholes during construction to identify possible changes in the soil and rock formations. Drilled shafts are increasingly used as foundations to support structures, bridges and other facilities in geomaterials such as soft-rocks and hard clays. Locating the bottom of the borehole during construction with the required design strength is critical. Hence developing a simple device that could be easily adapted/used with the drilling tool was of interest in this study. Determining the shear strength of the geomaterial in the borehole and at various elevations including the bottom of the borehole can lead to better quality control of construction by identifying the various layers based on strength. In this study, a down-hole penetrometer (DHP-CIGMAT) was designed, built, calibrated and tested in the field to determine its effectiveness in measuring the strength of soil/soft rock in the boreholes. Based on limited field tests, linear correlations between geomaterial strengths and DHP-CIGMAT deflection have been developed. The DHP-CIGMAT can be used to identify soils and soft rocks.