Search Documents

By K. Ski

Three series of membranes were prepared by blending polyvinylidene difluoride (PVDF) or poly(vinylidene difluoride-co-hexafluoropropylene) [P(VDF/HFP)] with sulfonated poly(ether ether ketone) (S-PEEK), sulfonated polysulfone (SPU), or sulfonated polystyrene, in order to develop novel PEM membranes suitable for melt processing. By means of incorporating fluorine-containing block copolymer into the blended system, acceptable proton conductivity and low water containing PEM materials were prepared. The effect of sulfonated poly([vinylidene difluoride-co¬hexafluoropropylene]-b-styrene) block copolymers as compatiblizers was investigated: conductivity was enhanced for S-PEEK/fluoropolymer blends. Microstructures for the blends were examined by transmission electron microscope (TEM) and scanning electron microscope (SEM).

Jan 1, 2005

By K. Pienimäki

Boliden Harjavalta Oy has produced copper since 1945. The essential idea has always been continuous development of process efficiency and environmental friendliness by using the Best Available Techniques (BAT). The ongoing development step is to increase the production capacity up to 210 000 tpy of anode copper and 155 000 tpy of copper cathode. One of the focal issues in this action is modernization of the copper refinery to utilize permanent cathode technology. This paper describes the refinery project and the technology used in it.

Jan 1, 2007

By G. Tozsin

A six-stage sequential leaching procedure was used to assess the leachability of heavy metals from waste rock in Antamina Mine. Sequential extractions procedure is well established for fine and small (? 1g) samples. However procedures for coarse and large test samples are lacking. This study presents results of the sequential leaches tests conducted on relatively coarse and large representative samples in terms of the availability and mobility of metals. Selective chemical reagents were used to extract metals from six different fractions where metals released with each subsequent extraction are believed to be bound tighter than those released in prior steps and therefore less likely to be leached.

Aug 1, 2013

Arguably the SMC Test® has become the most popular laboratory hardness test in the world with over 17,000 tests having been completed to date, covering over 650 different ore bodies. It is now routinely used in design, optimisation and orebody profiling projects. The test is unique in that from relatively small amounts of drill core it simultaneously provides parameters that are used in simulation modelling of AG/SAG and crushing circuits as well as work indices that are used in power-based equations for predicting the specific energies of AG/SAG/Crushing and HPGR circuits. The very large data base that has been accumulated has provided the opportunity to study the differences in variability from deposit to deposit. This paper describes and discusses the trends that have become apparent from the study of this data base. Recommendations for appropriate selection of sample numbers are also made which are based on these trends.

Jan 1, 2012

By Michel Gamache

This paper describes a system that manages and assigns vehicles in real-time in an underground mine. Each dispatching decision takes into account the traffic on the road segments of the mine network, whether bi-directional or unidirectional, and ensures that each LHD (Load-Haul-Dump Vehicle) arrives in the right orientation at loading and dumping points. Such systems can be used for two main purposes: 1) as a strategic planning tool and 2) as a real-time managing and optimising system for operations. Using a simulator in conjunction with the fleet management system, it is possible to accurately estimate the impact on productivity of decisions such as the development of waiting areas (bays, sidings), or the addition (elimination) of vehicles to the fleet in operation. Moreover, when used in for real-time dispatching, routing and scheduling of vehicles, the system can optimise production with respect to various assignment criteria such as minimising the cycle time or minimising the deviation from an optimal production plan. Dispatching, routing, and scheduling are handled simultaneously, taking into account the mine status, operational constraints, and all available information.

May 1, 2001

Some Statistics ? Feasibilitystudiescostbetween2% & 3% of capital andrequire8% to15% of total engineering effort ? Feasibilitystudiesusuallytakebetween8 and16 months ? Historically more than80% of projects fail to achieve all their objectives, usually blame the feasibility study ? What is bankable? Means that your promises will long be remembered. ? Poorly executed feasibility studies ? Driven by inexperience, unrealistic expectations, time constraints, financial constraints, lack of objectivity, front end loading activities incomplete or poorly done ? lack of minimum standard to provide a consistent approach Trend to improve???

May 1, 2010

By Marc Bétournay

This article examines how fuel cell technology and related power distribution system fits within mine operating requirements. Considerations for improvement of power plant architecture and functions to yield production advantages are presented. Improvements to conventional mining approaches are also discussed.

May 1, 2007

By Chuck Crowell

ISO Standards ?Provide Information to Address Commercial and Safety Needs for Standardization: ?Definitions and Terminology ?Test Methods ?Performance Criteria ?Conformity Assessment Process ?Developed by Global Experts ?Promote Global Harmonization

May 1, 2013

By S. A. Beeson, C. Poole

"This paper reports on the development of selective flocculation processes for the direct recovery of KCl values from low-grade Canadian sylvinite and carnallite potash ores.Two reagent suites, consisting of either a non-selective cationic or selective non-ionic flocculant, together with the same selective anionic dispersant, were evaluated. Initial data from component mineral behaviour investigations, reagent adsorption studies and selective flocculation tests on a synthetic potash ore were used in the successful development of processes capable of recovering KCl values without the necessity for desliming to remove water-insolubles.Enhanced multi-stage treatment (involving redispersion and reflocculation) and subsequent floc recovery techniques (including sedimentation, hydrocyclones and froth flotation) were examined, and in all cases the influence of process parameters such as reagent dosages, conditioning times, solids concentration, particle size and other physical design criteria were investigated.The data reported clearly demonstrate the scale-up potential of these processes and possible applications in potash operations."

Jan 1, 2000

By Andreea Catalina Gluhoi

Oxidation and reduction reactions of N-containing molecules have been studied over different types of gold-based catalysts, Au/MOx/Al2O3 and Au/MIOx/MIIOx/Al2O3 (M, MI, MII=Li, Rb, Mg, Ce, Zr, Mn, Cu) prepared by deposition precipitation with urea. In general, all the catalysts were already active at low temperatures. NH3 oxidation was effectively catalyzed by Au/CuO/Al2O3, a catalyst which also gives the highest yield in N2. NO reduction by H2 performed over gold-based catalysts produced N2O, N2 and NH3 and N2O reduction resulted in the formation of dinitrogen. For all the reactions, large synergistic effects have been obtained by addition of different kind of additives.

Oct 1, 2003

By U. Martin

Advanced copper materials for conducting applications require an optimal combination of high mechanical strength at ambient and moderately elevated temperatures together with superior electrical and thermal conductivity. Mechanical alloying under repeated cooling of the milling vials in liquid nitrogen has been applied to produce ultra-fine grained (UFG) oxide dispersion strengthened (ODS) copper with a high yield strength at ambient temperature. In the present study ODS copper was manufactured by mechanical alloying of copper powder and 3% by volume of incoherent oxide dispersoids. During the high-energy milling a homogeneous distribution of fine dispersoid particles (diameter nearly 100 nm) can be achieved in the powder. Samples with a density of more then 97% of theoretical value were produced by uniaxial hot pressing under 650 MPa at 600°C for 20 minutes. The high yield strength at ambient temperature can be described by a linear superposition of the Orowan stress for particle hardening and of ultra-fine grain strengthening according to the Hall-Petch mechanism. Simultaneously, a best value of 75% IACS could be obtained for the electrical conductivity. The creep behaviour of ODS copper in the temperature range from 500°C to 700°C is described within the frame of diffusional creep deformation.

Jan 1, 2007

By Stephan Day

Comments on Robust M3 to Protect Water Quality ?Regulatory and philosophical thinking have tended to evolve at decade scale since 1970s. ?Mines typically last more than a decade. ?Robustness is defined by the ability to adapt to new realities. Managing Water Quality in BC ?1973 ?BC Pollution Control Objectives ?1977 ?Federal Metal Mine Liquid Effluent Regulation (Fisheries Act) ?Late 1980s ?Philosophy of ?Designing for Closure? ?1990s ?Designing for Acid Rock Drainage Management ?2000s ?Awareness of need for water quality management in general, regardless of acidity

May 1, 2010

By W. M. Silva, PAP. Miotto, M. A. P. Silva, V. P. Ramos, L. R. M. Bittencourt

The major cause of breakdown of anode baking furnace fluewalls is chemical corrosion, which leads to deterioration of the properties of the bricks. Subsequent deformation of the fluewalls occurs, and also extensive cracking of the lining is observed. The present work studies the major changes of the brick during the operation of the furnace, after 22, 60 and 90 cycles of baking; in two different regions: upper and lower. Due to excellent cleaning conditions of the butts, negligible amounts of fluorine were found in the bricks. The major contaminants found were carbon, sulfur and alkali compounds, all of them present in the anode baked during the process.

Jan 1, 2004

By J. Zinck

The management of mine wastes generated by both active and inactive mining is an ever more challenging issue. The cost to manage and treat mine wastes, including tailings, waste rock, treatment sludge and slag, is estimated at over $50B in Canada and the United States alone. Cost-effective technologies are required to meet both short and long term challenges and increasing environmental standards. This paper will provide an overview of novel and conventional technologies to manage mine waste particularly in the areas of waste stabilization, treatment and disposal technologies.

Jan 1, 2004

By A. Fischersworring-Bunk

The new inline six spark-ignition engine is the realization of BMW's concept of efficient dynamics at high technological level to achieve the attributes of low weight and high efficiency, The paper presents different aspects of the development and manufacturing of BMW's inline six-cylinder engine magnesium-aluminium composite crankcase, Reference will be made on the AJ magnesium alloy optimization approach to balance between mechanical properties and the high pressure die cast ability requirements, Next to this aspect some mechanical design issues will be covered, with CAE methods playing an instrumental role in the early project stage for the assessment of the compound concept, Due to the compound design chosen, the interface posed challenges to both design and productions, A set of novel techniques has been used to cope with these tasks.

Jan 1, 2006

By M. Özer, F. Boylu, G. Önal

In this study, the fine coal waste subjected to the experiments is taken from the waste stockpile of Soma Coal Plant. The possibilities of its evaluation and the production of clean coal were investigated. For this purpose, Reichert Coal Spiral and Shaking Table are used. The minus 1 mm coal waste includes 60.43% ash and 50% minus 38 micron material by weight. The microscopic observations of the screen fractions were shown that the clay minerals are in fine sizes and the coarser size fractions contain silica and carbonate minerals as ash forming materials. The tests were conducted after desliming. The commercial grade clean coal product containing 29-35% ash with a calorific value of 3800-4200 kcal/kg (15.91-17.58 MJ/kg) was obtained by gravity methods.

Jan 1, 2004

Cameco Corporation is in the process of revitalizing the Key Lake mill. As part of this process, the company is considering installing the Rabbit Lake style strong acid stripping in solvent extraction. This would lead to using hydrogen peroxide for uranium precipitation. The process currently employs ammonia stripping and ammonia precipitation. As part of the process evaluation, an indirect fired drier pilot plant test was conducted. This paper will discuss the results of that test work, including the relationships between the following: ? Drying temperature and product grade ? Drying temperature and product colour ? Drying temperature and product reactivity with water ? Drying temperature and energy input requirements ? Drying temperature and shipping costs

Aug 1, 2010

By G. E. Joe

"This is a panel discussion on the milling experience with large volume flotation machines in Canada. Over the past ten years, the Canadian milling industry has been characterized by treatment of ever increasing tonnages of lower grade ores. In order to treat these ores efficiently, mineral processors have been employing increasingly larger volume flotation machines. In older established mills, standard flotation cells have been replaced by the larger volume models with very apparent savings in mill floor space as noted in the Opemiska copper mill.We are pleased to hear from four mill operators with extensive experience on large volume flotation machines. They are:1. I. E. Wahn, metallurgist with Falconbridge-Manibridge, who will describe their mill experiences with the Tank cell and the Maxwell cell.2. G. M. Hughes, mill superintendent of Sherritt Gordon-Ruttan, will detail recent experience with the Agitair cell.3. J. R. Maxwell, mill superintendent of Opemiska Copper, will report on their Maxwell cell installation and operation.4. A. H. Winckers, superintendent of Development and Technical Control, Sullivan Mill, will present a paper written by H. J. Chalmers describing Cominco's past experiences with large volume flotation machine installations including Denvers, Wemcos and Maxwells."

Jan 1, 1974

By H. Nakano

The codeposition behavior of impurities such as Ag, Bi, Fe, Ni, Pb and Sb with Cu was investigated galvanostatically at 5-3000 A/m2 using a Pt cathode at 60 °C in acidic copper (I) chloride (cuprous chloride) solution at pH1-2 containing 1.0 mol/L of Cu+ and 4.9 mol/L of Cl-. The impurities were classified into two groups: Group I (Ag, Bi) which codeposits with Cu as a metal, and Group II (Fe, Ni, Pb, Sb) which is slightly involved in the deposited Cu in nonmetal form from the electrolyte. Silver and Bi in Group I behaved as more noble metals than Cu, and significantly codeposited with Cu, showing typical features of regular-type codeposition. When Cu was deposited dendritically, the Ag and Bi content in the deposit increased with increased duration of electrolysis as a result of decreased net current density caused by increased cathode area. The current efficiency for Cu deposition in impurity-free solution was 95-100% over 100-1000 A/m2, but it abruptly decreased at above 1000 A/m2 when the limiting current density of Cu was attained. Although Fe, Ni, Pb and Sb in Group II were involved to 0.01-0.02 mass% in the deposit, they had no influence on the current efficiency or morphology of Cu.

Jan 1, 2007

By L. Mercier, A. El-Hsaeri, L. Amaratunga

Laboratory scale studies of the development and application of high capacity heavy metal ion adsorbents with uniform nanoscale porosity (denoted MP-HMS, mercaptopropyl - hexagonal mesoporous structure) to extract gold from solutions is described. The adsorbents are selective towards gold ions. The adsorption capacities of these materials are also among the highest reported. MP-HMS has shown the capability to adsorb 330-mg gold per gram adsorbent (up to 30% of their weight). Gold uptake by the adsorbent was found to increase dramatically with solution agitation. The adsorbent was found to be extremely effective in adsorbing gold ions from ultra- low concentrations, like those found in mine effluents. Experimental studies indicated that MP-HMS maximum adsorption of gold (99.9%) occurred under all solution concentrations. Another promising attribute of these materials is their favorable adsorption kinetics. The contact time required for 80% adsorption of gold was found to be less than 60 seconds. The efficiency of these nanoporous materials for the recovery of gold from mining effluent is evaluated and their prospect for application in the mining industry discussed. The process thus has the prospect of becoming an efficient and environmental friendly method to recover gold from aqueous solutions, such as gold mill effluents.

Jan 1, 2004