Blogs
Improving Crushing & Grinding Rates and Recovery Efficiency
The crushing section was designed to supply approximately 100 tons per hour of -5/8 in. material to the Fine Ore Bin. Early milling results indicated that the ore was somewhat harder than expected and the 7 ft. x 10 ft. Hardinge Rod Mill was proving to be a bottleneck. The comparatively wet ore, sizing up to 14 in., is fed
Heap Leaching Oxide and Sulfide Copper Ores
Table of ContentsExperimentalOres used in this StudyAssaying of SamplesLaboratory StudiesProcedures Used in Laboratory StudiesExperimental DataDiscussion of Experimental ResultsField StudiesDescription of Leach Column and OperationsExperimental DataExperimental ResultsEstimation of Heap Leaching Results from Laboratory Studies on Crushed OresTime of LeachUltimate Economic Recovery and Acid Consumption at the Ultimate Economic RecoveryConclusionsAcknowledgementsDetermination of Free AcidScopePrincipleEquipment and SuppliesProcedureAccuracy Heap leaching is a simple means of
Grinding Circuits Simulation of Closed-Circuit Grinding
The data acquisition and modeling efforts are described first, followed by discussion of some of the simulation results. Observations pertinent to steady-state operation are presented followed by a description of the application of a dynamic model of the grinding circuit for synthesis and evaluation of grinding-circuit control. Data Acquisition and Reduction Eleven streams are identified. Stream 1, shown as a
Grinding and Classification Control
Table of ContentsDescription of the Grinding-Classification Circuit Instrumentation in the Grinding-Classification Circuit The ore milled from start-up until January, 1968, was mainly massive sulphides, consisting of a complex mixture of iron, copper, zinc and minor amounts of lead sulphides with important associated values in gold, silver and cadmium (average specific gravity 3.8). Description of the Grinding-Classification Circuit The crushing plant product
Fine Dry Grinding of Iron Ore for Pelletizing
Table of ContentsDesign Considerations for Selecting a Grinding SystemOpen vs. Closed Circuit Dry GrindingEffect on Pellet QualityOperating Considerations Screening during the production of high-grade lump ore for blast furnace burden, particularly from recently developed ore deposits in Australia, South America, and Africa, has resulted in large tonnages of fine iron ore. Certain owners have decided to stockpile these fines until
Design of Flotation Cells and Circuits
Table of ContentsPrinciples of Machine DesignDesign Problems for Larger CellsCircuit Design and Operation After almost 60 years of application in this country froth flotation is still by far the most important process for concentrating metallic ores as well as a number of nonmetallic ores including fluorspar, phosphate rock, and potash. Its use on iron ores and coal is increasing. In
Tailing and Mill Process Water System Design Considerations
When the Henderson Project is completed in 1975, it will become one of the Free World’s largest primary molybdenum producers. The Henderson Mine will be located approximately 50 miles west of Denver, Colorado, on the eastern slope of the Continental Divide. Ore reserves are currently estimated to be 303,000,000 tons with a grade of 0.49% MoS2. The mill and tailing
Cyclone Separators for Solvent Extraction in Metallurgy
Solvent extraction as a method of purifying and concentrating metal values from solution has become a standard hydrometallurgical operation for recovery of both uranium and vanadium, and within the past two years it has been put into operation in a commercial plant for recovery of copper from leach solutions. In this first full scale solvent extraction plant for recovery of
Iron Ore Crushing & Grinding Controls
Table of ContentsPrimary CrushingRod Mill – Ball MillWet Autogenous – Ball Mill The Iron Ore Industry has perhaps seen more varied and drastic changes in its approach to crushing and grinding in the last 5 years than any of the other mineral industries. Multimillion ton per year plants have become common place. Centralized control and computers have become an established
Copper Electrolite Solution Filtration
The electrolyte in-between the active electrodes must be purged with higher velocities to maintain a high concentration of the desirable copper ion in the liquid film adjacent to the cathode and the sulfate ion in the liquid film at the anode. This higher velocity also carries away from the cathode the undesirable impurities released from the anode as they are
Grinding Circuit Control – South Africa
Table of ContentsMill ControlsAutomatic Control of the Milling CircuitMilling Control System In a minerals-recovery context, the object of exercising control over milling operations must be threefold. To achieve maximum recovery at minimum operating costs and making maximum use of installed equipment. Milling is one of a sequence of operations which have as their objective the economic recovery of minerals from
Using a Crusher to Control Autogenous Grinding Circuit
Table of ContentsDescription of Pilot PlantDescription of Samples EmployedResults of InvestigationsEffect of the Crusher on the Size Distribution of the Grinding Media In an autogenous grinding circuit in which feed at approximately nine inches top size is reduced to a size suitable for subsequent processing, the build-up of a “critical size” fraction in the media causes problems. A “critical size”
Feed-Forward Control for Grinding Circuits
Feed-forward control ( i.e. the forward flow of information in a control system ) is a simple and flexible approach to over-all control of a ball mill-rake classifier grinding circuit. The system described here uses mill power, feed rate, mill dilution water flow rate, and classifier dilution water flow rate only, to control mill load, throughput, mill solids, and classifier
Large Tonnage Fine Crushing Plants – Trade-Off Study
Table of ContentsFactors Affecting DesignTypical Layout IllustrationsStacked ArrangementLow Profile – Open Circuit Common practice for size reduction of run-of-mine or run-of-pit ore in preparation for subsequent treatment utilizes a three-stage system. First stage, or primary breaking is generally carried out with jaw or gyratory crushers. The usual output from this stage provides a feed for fine crushing in the size
Chromium Electroplating
Electroplating is a widely utilized but little understood process, the fact that the average person is in contact with dozens of plated items daily without even being aware that they are electroplated is evidence of the success of the process, although a complete explanation of electrodeposition involves thermodynamics and modern theories of bonding and catalytic reactions, in its simplest form
Bulk Sampling Method
Table of ContentsThe classical 4-step sampling techniqueMaterial Variability – A Major Consideration in Sampling PlanThe Collection of SamplesEquipment and Component Design Bulk sampling is define as the “process of extracting a small fraction of material from a large bulk sufficiently representative for the intended purpose”. Today’s pressing need for simple, effective and reliable sampling systems is intensified by the growing
Blasting Mechanics
Table of ContentsSummary of Experimental ResultsOne-Shot” Pin Performance The term “powder factor” is almost universally accepted as the measure of the efficiency of a blasting program. It represents the economics of blasting since it designates quantity of explosive (thereby providing quality control in rock fragmentation) in terms of the associated volume broken. It is the wide use of this concept
Conveyor Belt Scale Design
Table of ContentsScale SuspensionLoad Sensing DevicesIntegrators & Totalizers Weight may be defined as the gravitational attraction or earthpull on a body (mass). Thus, from a practical viewpoint, a scale or other form of weighing device is a means for determining mass. Weighing devices fall into two principal categories: (1) gravimetric; and (2) non-gravimetric or nuclear devices. At present, after many
Using Platinum Electrodes to Indicate Redox Potential
Table of ContentsExperimental ProcedureExperimental Results Platinum electrodes are not inert as originally thought to be. The reactivity of platinum electrodes can explain their erratic behavior in many electrochemical measurements of metallurgical interest, e.g., in flotation systems, streaming potential measurements, contact-angle measurements, and in leaching systems. Experimental Procedure A rotating platinum electrode was used in many of the measurements to study
Granulometric Separation of Granular Materials
Table of ContentsPrinciples and Description of the Sieving – PanelIndustrial TestsResults of the tests Classical apparatus for granulometric separation generally have limited applications which are found either in the level of the size of separation or in that of the accuracy and the efficiency of the separation or in that of the rate of feed. Principles and Description of the
Aqua Regia for Total Copper and Zinc Content of Granitic Rocks
One of the analytical problems in exploration geochemistry is the choice of a method of sample attack which would be rapid, simple and reliable in terms of precision and discrimination between different concentration levels of elements sought. The wet sample attacks currently used in analysis of silicate rocks vary from total decomposition to leaching by weak extractants. The total decomposition
Treatment Methods for Mining and Ore Processing Wastewaters
Increased emphasis on industrial pollution control has intensified investigation of waste treatment technology for methods of reducing the amount of pollutants discharged by industry. The mining and mineral processing industry can point to a record of considerable accomplishment in the field of wastewater treatment and reclamation because these operations are so frequently an integral part of the entire operation of
Thickener Design and Theory Problems
Table of ContentsThickening RegimesKynch TheoryLower Conjugate Concentration ZoneCompressionChannelingThe Compression PointWhat Is an Engineer to Do? This paper will review thickening theory, from the study but of the practicing engineer, with particular emphasis on areas of uncertainty or disagreement. It will attempt to outline broadly what we know and what we don’t know. This should serve two purposes. First, it will
Tailings Dam Sealed by Slimes Slurry
In 1965, Monsanto started planning of a new dike (No. 15) for use in disposing of ore tailings at its Columbia, Tennessee phosphorus plant. Generally, in the phosphorus industry only clay tailings are produced making it necessary to borrow fill for construction of a retaining dike. Borrow area investigations indicated that weathered shales and limestones adjacent to the dam site