Blogs
Best Air Sparging System for Column Flotation
Table of ContentsTest ResultsBenefits Objective: Provide a low-maintenance, reliable means of generating bubbles and controlling bubble size for column flotation. Approach: Commercial sparger systems used in flotation columns to process minerals provide only limited means of controlling the size of bubbles generated and the rate of air injection. Generally, these limitations are a detriment to flotation performance, particularly in recovering coarse or
Water Jet Cutting to Reduce Dust
Table of ContentsHow it WorksLongwall shearerLarge-diameter boring machineRoadheader Objective: Use water-jet-assisted cutting technology to reduce the exposure of mine workers’ to respirable dust. Approach: Install water-jet-assist on mining machines and evaluate its impact on respirable dust. How it Works Water-jet-assisted cutting involves a mechanical cutting bit working in combination with a moderate pressure (generally up to 10,000 psi) water jet directed just
Cutting Rock by Water Jet
Table of ContentsTheories of Water Jet AssistanceLubricationStress Corrosion CrackingSuppression of Secondary ChippingHydraulic WedgingErosion of Crushed Rock The use of water jets to augment mechanical rock cutting has advanced greatly since the discovery a decade ago that water jets diminish the forces acting upon drag bits cutting in strong rock. Other research workers cutting in a wide variety of rock types
Monorail Bridge Conveyor System
Table of ContentsDescription of Monorail Bridge Conveyor SystemConveyor UnitsPower and ControlTramming and Support SystemInby SupportOutby SupportSurface TestingTest Rig InstallationInitial CheckoutPower ConsumptionDisabled Brake TestHaulage RateMiner Loading TrialsReliabilitySystem Compatibility with Low-Belt StructureSuspension of Monorail Track by Chain HangersSystem Compatibility with Hopper-FeederSummary of Surface Test FindingsModificationsMining Plans The Bureau of Mines has sponsored numerous high-risk research programs over the past decade to improve
Stop Mining Method
Table of ContentsStop Mining Flat DepositStop Mining Inclined Deposit Stop Mining Flat Deposit In the previous topic you were introduced to the different methods adapted to mine underground deposits. Well the basic elements are common to most underground mining operations, there are many variations in the theme. In the next three topics we will see how these methods can be
Zeolite – Natural and Synthetic
Table of ContentsDefinitionsStructure and ClassificationFormation Processes and Geologic OccurrenceSaline Alkaline LakesSaline Alkaline SoilsMarine SedimentsOpen Hydrologic SystemsHydrothermal SystemsBurial Diagenetic SystemsMagmatic SystemsImpact CratersExplorationSynthesisChemical and Physical ModificationDehydration and RehydrationStructural Hydroxyl GroupsSorption and DiffusionMolecular SievingDiffusionPore VolumeZeolites and CatalysisEconomic ConsiderationsApplicationsSummary Zeolites are crystalline aluminosilicates of the alkaline and alkaline-earth metals. They possess many desirable ion- exchange, molecular sieving, and catalytic properties, which make them valuable
Water Filtration by MgO Magnesium Oxide
Table of ContentsFiltration MechanismsTransient BehaviorFiltration IndicesContact Filtration of Asbestos FibersGranular Bed FiltrationSynthetic SuspensionsFiltration of KaolinFiltration of Milled SandUse of Polymer FlocculantsKaolin FiltrationFiltration of Metal PrecipitatesFiltration With Mixed MgO-Sand BedsApplicationsSteel Mill Cooling WaterProcess Water from Magnetite BeneficiationProcess Water from Flotation of Iron OreProcess Water for Cutting GraniteBackwashing of Mgo FiltersAttrition of MgO Filters during BackwashingPoisoning Of MgO Filters by Heavy MetalsMagnesium
Fuse Wire Arc Tester
Table of ContentsMechanical ApparatusElectrical CircuitExperimental Method When certain insulating materials are decomposed by heat, highly explosive gases can be released. These insulating materials cannot be used within enclosures containing high-voltage circuits because they may be subjected to destructive electrical arcing. The commonly used method in the United States for determining if materials are highly resistant to electrical tracking is the
Grinding Mill Liner & Ball Corrosion Rate
Table of ContentsElectrochemistry of CorrosionLaboratory Test MethodsSynthesis of Ore SlurrySimulation of Abrasive ConditionsDetermination of Potential-Current DataLaboratory Test ResultsCorrosion Rate Measurements in a Copper Ore MillEquipment DesignElectrode AssembliesWiring SystemPotentiostat-Computer for Making Potential-Current ScansCopper Mill Test ResultsComparison of Laboratory and Copper Ore Mill TestsAdvanced Field Test Equipment DesignAnalog-Digital ConversionRadio Transmission of DataData Reception and ProcessingCorrosion Rate Measurements in an Iron Ore MillComparison
Grinding Cement Clinkers
Most Cement Clinkers grinding experiments were carried out in a 29.2 cm diameter laboratory ball mill which had a built-in wavy liner. The ball charge consisted of 1.27, 1.90 and 2.54 cm steel balls mixed in equal proportion by number. The ball load corresponded to 40% filling of the struck volume of the mill (denoted by: J = 0.4), and
Mining Engineering & Mineral Exploration Economics
Table of ContentsMineral ExplorationIs a Mineral Deposit EconomicMining Engineer Tasks & Responsibility Mining Engineering is a lot about applying the knowledge of applied science and Engineering Mechanics to the successful extraction of useful geological resources. So in this first module we will overview the mining process in its entirety and identify those aspects which are the realm of the mining
Rock Mass & Rock Matrix – Discontinuities
In this topic we will discuss what constitutes a rock mass and its relevance for engineering.in this photo, you can see a rock face and what is quite clear is that the rock is not homogeneous. Compare to this specimen of sandstone, which has a uniform color and no clear planes crossing it. In contrast, the photo shows many lines,
Mining Geomechanics – Stress & Strain
Table of ContentsStrain ExperimentStress Experiment We’re going to introduce in this topic the two key variables required to define the fundamental behaviour of materials. These variables are stress and strain. In many engineering applications it is required to assess how a structure deforms or behaves under a load. Making such an assessment requires some knowledge about the material constituting the
Pyrite Oxidation Kinetics – How Fast does Pyrite Oxidize
Pyrite oxidation has been studied extensively, in the past, because of its importance in sulfide mineral separations by flotation, in the generation of acid in mine waters and in leaching of pyrite. The oxidation of pyrite also plays key role in supergene alteration of ore deposits, the formation of acid sulfate soils, etc. Pyrite oxidation is generally recognized as a
Bioleaching Preg Robbing Gold Ore
Refractory precious metal ores in which gold is encapsulated within iron sulfide minerals can be effectively treated by other leaching bacteria in addition to T. ferrooxidans. These include both facultative and obligate thermophiles. Use of thermophilic bacteria for microbial pretreatment of precious metal ores can offer economic advantages over common bioleaching processes in terms of both increased reaction rates and
Borate Leaching – In Situ Recovery of Boric Acid
Figure 3 shows a flowsheet of the patented process which involves injection of acid into the deposit, recovery of boric acid-rich solution from production wells and crystallization of boric acid by solar evaporation. The preferred acid in the Duval process is hydrochloric rather than sulfuric acid. The higher initial cost of hydrochloric acid as compared to sulfuric acid is overcome
Bacteria Leaching of Gold Encapsulated in Pyrite
It is known that many of the gold and silver deposits are often associated with sulfide minerals, specially pyrite. Some of the precious metals in such ores are often found as very finely disseminated particles inside the sulfide crystals. The encapsulation of the precious metals particles in this manner makes their extraction very difficult, as these metals become inaccessible to
Determine Mineral Liberation using Breakage Rate
Table of ContentsCharacterizing Liberation Using Breakage RateCharacterizing Liberation Using the Cumulative Liberation Function It is quite clear from the data shown in the previous section that parameters for a liberation model can be experimentally determined using image analysis techniques, and that these parameters can be used to successfully simulate the liberation process. However, the process of experimentally determining these model
Column Flotation Parameters
Table of ContentsEffect of Column LengthEffect of Feed Injection PointEffect of Froth DepthEffect of Wash Water Addition RateEffect of Tailings RecirculationEffect of Particle Size Fractions Investigation of coarse bubble column flotation resulted in identification of four distinct beneficiation zones of a flotation column. Comparison of average normalised percent mineral upgrading per foot values (zkn) indicated the relative degree to which these zones contribute to overall column mineral grades and recoveries. The
Heap Leaching Practices
Table of ContentsMineralizationOre ProcessingLeach Pad PerformanceRecovery Curves / Summary Gold Fields’ Mesquite mine, located in southeastern California, heap leaches low grade gold ore at an annual rate of 2.7 Mt (3 million st). Ore is crushed in a two stage open circuit and belt agglomerated prior to loading on the leach pads. Since initial heap construction in October of 1985,
Modelling and Control of Ball Mill Grinding
Table of ContentsGrinding mill modellingConstrained minimum variance control Dynamic experiments were performed in a continuous open-circuit 40×40 cm ball mill using a pseudo-random binary sequence of the feed rate and measuring the variations of the discharge particle-size distribution. The impulse response is calculated by a cross- correlation technique. Then a model involving a discrete transfer function and a time-series stochastic
Column Flotation of Copper
Table of ContentsColumn Cell DesignColumn Cell Operation A practical application of recent design concepts makes it possible to design a column cell to fit a specific set of conditions. The design and operating parameters of a column cell installation that replaced a conventional two stage copper flotation cleaning circuit at MAGMA COPPER COMPANY, SAN MANUEL, ARIZONA using these design concepts
Cobalt Mineralization – Cambrian Mississippi Valley Type Rocks
Cobalt-sulfide mineralization can be found in potentially economic quantities where permeable, basal Cambrian formations “pinchout” against Precambrian paleotopographic highs. These environments are common around the Saint Francois Mountains of southeastern Missouri and they share many similarities with the geologic environments of Zambia and Zaire in South Africa. Exploration Philosophy Exploring for cobalt-bearing minerals in southern Missouri’s lead-zinc district, Molycorp made
Mining Exploration Process
How Explorers develop an exploration strategy, how they develop an exploration model and design an exploration program and select the optimal exploration tools to carry out that program. As usual of the talk will end with a series of learning points from this talk. There are two fundamental truths about the exploration industry; the first is that most exploration