Blogs
Air Classification of Fly Ash
Fly ash is classified as a natural pozzolan and finds significant use as a cement additive. It has been found to increase the plasticity of the cement mixture while lowering the amount of mix water needed. In addition to improving leveling and finishing properties, fly ash improves pumpability as well as decreases the heat of hydration of the concrete mix
Particle Segregation in Hydrocyclones
Table of ContentsModel of Cyclone Behaviour under Ideal ConditionsCyclone Behaviour under Real ConditionsDensity partition curve Size partition curve for δ=p (CD line)Dynamic lifting effect on particlesExperimental Data In mineral processing, segregation means a non-uniform distribution of particles with different size, shape and density among the various streams exiting a process plant or a generic operation unit. This term is generally applied
Improve Performance of Copper Solvent Extraction Process
Table of ContentsR320 Development Research PhilosophyHead-Flow OptimizationDroplet CharacterizationShear Gradients50:50 DispersionsFull Scale VerificationOptimizing Design & Operation of your Pumper and Auxiliary Impellers LIGHTNIN pioneered impeller developments in the early 1980’s that allowed axial flow impellers (A310) in the auxiliary mix boxes of SX plants to reduce shear and entrainment while providing good contacting of the aqueous and organic phases. However, the
Distribution of Gold and Sulfides
Table of ContentsControls of Gold and Sulfide Distribution at Lupin NWTRegional SettingGeologyDeformationPlutonismGeology of the DepositStratigraphyMetamorphismStructureMineralogy of the Amphibolitic Iron FormationsGarnet AmphiboliteSulfide-Poor Iron FormationSulfide-Rich Iron FormationQuartz Veins and MineralizationSampling MethodologyDistribution of Gold and SulfidesDeposit-Scale Zonation of Gold Values Lupin is located on the shores of Contwoyto Lake at lat. 65° 48’N, Long. 111° 15’W and lies about 80 kilometres south of
Integrating Plant Wide Control of Supervisory Expert System
Table of ContentsPlant-Wide Control ConceptsPlant-Wide Control System ArchitectureProcess Control StrategiesKnowledge Base OrganizationSag MillRecycle Crusher ControlBall MillRougher FlotationCleaner Column FlotationIntegration of Unit OperationsPractical Aspects of ImplementationPersonnelBenefits of Supervisory ControlFlotation Control Opportunities for maximizing corporate revenues through plant-wide process control strategies are being sought in virtually all industries. The mining industry, in particular, can realize tremendous benefits through implementation of systems that
The Start Up of Cerro Colorado Mine
Table of ContentsExploration HistoryGeologyMiningCrushingAgglomerationHeap Leach PadConveying and Stacking SystemSolvent Extraction/Electrowinning (SX/EW) Location Cerro Colorado lies on the eastern edge of the Atacama desert in the foothills of the Andean Cordillera of northern Chile. One hundred and twenty kilometers east of the port city of Iquique, the mine site is accessed by 30 km of paved highway and 70 km of
Gold and Silver in Eddy Current Separator Processed Electronic Scrap
Table of ContentsGeneral Avionic ScrapBaghouse LightsWire BundlesMagneticsEddy-Current Precleaner MagneticsEddy-Current AluminumEddy-Current MiddlesEddy-Current RejectsHigh-Tension MetalHigh-Tension RejectsKnockout Box ContentsPrinted Circuit CardsElectrical Plugs and ConnectorsEconomicsRecommendationsConclusions The Bureau of Mines investigated the concentration and distribution of precious metals in the various fractions produced from mechanical processing of obsolete military electronic scrap. Whole avionic units, printed circuit cards, and electrical connectors were processed and analyzed. Materials
Batch Thickening Theory
Kynch showed that a constant concentration layer propogates upward at constant rate in batch thickening tests under the assumption that settling velocity is a function of only the concentration, as described earlier under Continuous Thickening Theory. His conclusion can be expressed as: Where Ci is the concentration of solids in the layer, and Vi is the settling velocity of the
Selecting Thickener Depth Determination
Table of ContentsThickener Compression TestsTest Results without CompressionTest Results with Compression Where there is little significant effect of compression factors, the bed depth can be selected based upon operating characteristics of the thickener installation. In this case, information must be available (or assumed) concerning the normal fluctuations in feed rate and concentration. Also, sludge storage requirements should be considered. For
Flocculation
Table of ContentsEffect of pH and Ionic StrengthEffect of Molecular Weight The flocculation behavior of coal, quartz and clay was studied by measuring the turbidity of the supernatant liquid after one hour of settling. Figure 14 is a plot of turbidity and adsorption density against equilibrium concentration. The turbidity of the supernatant liquid decreases until a minimum is reached and
Rheology of Polymer Solutions
Viscosity measurement represents one of the simplest experimental techniques for characterizing polymers. In general, the viscosity of a polymer solution depends on the molecular weight of the polymer and on the configuration of the molecules. For essentially linear polymers such as the polyacrylamide flocculants, coiling of the molecule in response to changes in its environment leads to changes in viscosity
Continuous Thickening Theory
In a continuous thickener the downward solids velocity with respect to the thickener wall is the sum of the settling velocity of the solids by gravity alone, Vi, plus the downward velocity caused by removal of the thickener underflow, U. The rate at which solids move downward by gravity alone is expressed as the product of the concentration of the
Polymer Adsorption
Table of ContentsEffect of Surface AreaEffect of Solid AdsorbateEffect of pH and Ionic StrengthEffect of Molecular Weight Adsorption measurements on all the solids were carried out by the methods described above. Figure 2 shows a typical isotherm for the adsorption of polymer A on coal. The adsorption density rises monotonically until an apparent plateau is reached. For the case shown
Assaying Reagents
Table of ContentsReagents used in Fire AssayingREDUCING POWERSOXIDISERSFLUXESDESULPHURISERS AND SULPHURISERSWET REAGENTS USED IN FIRE-ASSAYING It is essential for the assayer to be assured of the fact that his reagents are pure, or at least to know to what extent they are impure and what the impurity consists of. For this reason it is necessary to examine lots of reagents from
Geotechnical & Construction Aspects of ON OFF Leach Pad
Table of ContentsGeotechnical ConsiderationsLeach Pad Design and ConstructionFill Construction ConsiderationsSelection of Fill MaterialsDesign and Construction ApproachInstrumentation and TestingLiner SystemDesign Criteria and Geomembrane MaterialsTensile and Seam PropertiesInterface Shear StrengthLiner System Cross-Section Project Description Exploration and development of the project by Rio Algom Ltd. began in 1981. Feasibility and design studies were ongoing in the 1980’s culminating in a decision to develop
Air Sparged Hydrocyclone Flotation & Bubble Generation
Table of ContentsResults and DiscussionSurfactant ConcentrationShear ForcePore size Air-sparged hydrocyclone (ASH) flotation is one of the new promising technologies. Numerous applications have been successfully tested since its conception; nevertheless, research and development efforts have continued to provide for further improvements with respect to operating conditions and design considerations. Bubble size is always of interest in the analysis of flotation separations.
Controlled Blasting
Table of ContentsBlast DamagePropagation of VibrationsControlled Blasting TechniquesControlled Blasting DesignControlled Blasting ExperimentsAnalysis of ResultsExplosives Malfunctions Rock fragmentation by explosives is presently the most inexpensive process available to the hardrock mining industry. The challenge remains, however, to control the explosive energy to optimize fragmentation produced by blasting and minimize the deleterious effects associated with the use of explosives. These harmful effects
Centrifugal Modeling
The centrifuge modeling technique is a powerful tool for geotechnical engineering in general. It has been used for over sixty years to model soil behavior. Regarding phosphatic clays, centrifuge research has been actively conducted in the last decade by several investigators to predict the field consolidation of these clays. In this technique, a physical model is built with an at-rest
Caro’s Acid Cyanide Oxidant Detoxification Destruction Process
Table of ContentsProcess DescriptionEffect of Caro’s Acid On pH This powerful CN- detoxification agent is prepared by mixing concentrated sulfuric acid and concentrated H2O2. H2O2 + H2SO4 → H2SO5 + H2O The formation of Caro’s acid is instantaneous and is accompanied by the evolution of heat, primarily due to the heat of dilution of sulfuric acid. Because of it’s tendency to
Solvent Extraction Stripping Methods
Table of ContentsExperimental Materials Equipment and ProceduresGeneral SX and stripping proceduresParticle size analysisCopper ore LeachateHydrolytic iron strippingZirconium precipitation stripping To remain competitive, the domestic metals industry must not only make advances in mining methods, but also in ore processing. One processing advancement under investigation is the development of nonconventional solvent extraction (SX) stripping techniques such as hydrogen, hydrolytic, and precipitation
Pressure Oxidation Leaching Process
Batch Autoclave Laboratory Procedures: The vessel used for the laboratory pressure oxidation process was a two-liter Parr titanium autoclave with dual impellers. It was heated and cooled externally and was pressurized with commercial-grade oxygen. A positive bleed of offgas was maintained in each test; the rate was measured in the offgas after the steam was removed with a condenser and desiccant.
Infill Drilling Program Design
An exploration process is normally consisted of four major phases: regional reconnaissance, detailed mapping, sparse drilling, and infill drilling. Regional reconnaissance focuses on promising areas for a given type of ore deposit by using geological, geochemical, and geophysical data. Once one or more areas are selected, a detailed mapping program will be enacted in order to delineate drilling targets. This
In Situ Mining Well Construction
Table of ContentsOrder of Well Design SpecificationWell Construction Materials and EquipmentWell Completion DiscussionINJECTION WELLRECOVERY WELLSummary of Costs for Well Construction and Completion The objective for this U.S. Bureau of Mines (USBM) research is to evaluate construction and completion methods and costs for vertical in situ copper mining wells to depths of up to 1100 m (3600 ft). Appropriate construction materials
Magnetic Separation of Clay
Conventional Magnetic Separator: An Eriez conventional high gradient magnetic separator (HGMS), model EL 20-4, with a 0.058 m canister diameter and a total volume of 1030 cm³ was used. The matrix was a fine grade stainless steel wool. The canister was packed to a 6 percent density with the matrix. The tests followed the recommended Eriez procedures. Procedure: Crude kaolin samples