Blogs
Medium Circuit Design and Control for Multi-Density Dense Medium Separation Plants
The two-density separation by dense medium cyclones was generally performed using two dense medium plants in sequence. In contrast to the former technology, the multi-density separation can now be performed by using a single medium circuit composed of different interconnected medium sumps. The sumps, one for each density, are fed with different medium streams selected according to their density, size
Paste Backfills Types
The basic rule for a material to have paste fill flow properties is that it has at least 15 wt% of its particles finer than 20 microns. This generally ensures that the material has the required colloidal properties and is not self draining. What this means is that the material, when mixed with sufficient water to produce a 150 mm
Gold Redox ORP Probes used in Flotation Circuit
Three gold sensing electrodes were made from 3 mm gold rod. The rod was cut with a diamond wafering saw into 3 mm lengths, soldered to insulated copper wire, placed inside 9 cm lengths of 1 cm (outside diameter) Plexiglas tubing, and cast inside the tubing with epoxy. After the epoxy was set, the gold was polished with 600 grit
Shaft Sinking and Ramp Excavation
Table of ContentsGround ConditionsHydrological ConditionsCost Estimate General Criteria and AssumptionsRamp Construction Cost Estimate Mine planners and engineers are often faced with the decision of choosing which method of underground access is best suited for their particular requirement. Underground access can be provided by a shaft, ramp, adit, or slope for either exploration and/or actual production operations. The selection of the
Titanium Mineralogy
Table of ContentsOre CharacteristicsExperimental ProceduresMineralogical and Petrographical CharacterizationMineral-Chemical Analyses by Electronic Microprobe The study of minero-petrographical characteristics and the subsequent textural and structural characterization of an ore mineral represents the first step of each industrial processing whose aim is the beneficiation of each valuable mineral phase present inside the ore. Analytical, mineralogical and petrographical, chemical and multispectral image analyses based
Flocculation & Zeta Potential Measurements
Chemicals: Reagent grade H2SO4 and KOH were used for pH adjustment. Aluminum sulfate was used for coagulation and zeta potential studies. Percol 368 a solid grade highly cation flocculant by Allied Colloids Inc. was used for flocculation and zeta potential measurements. Methods: Zeta potential measurements of the slurry as received and/or after treatment with different chemicals, were conducted using Laser
Classification of Ultrafine Magnetite and its Effect on Fine-Coal Dense-Medium Cycloning
Testing was conducted previously to investigate the effects of cyclone geometry and flow rate on the occurrence of apparent bypassing when separating 150×25µm anthracite in a 25mm diameter cyclone. Apparent bypassing indicates that some fraction of the feed coal bypasses or short circuits directly to the clean coal and/or refuse streams, independent of the separating action in the cyclone. The
Optimal Design of Mining Panels for Truck Shovel Operations in Large Open Pit
In the planning phase, the entire surface area is usually divided into mining panels which are later mined and reclaimed with a particular sequence. Panel dimensions and their relative orientations affect in-pit waste haulage distance, stripping ratio, production efficiency, and facility layout. Generally, for the same production rate of coal, reduction of panel width will reduce in-pit waste haulage distance.
Column Flotation of Copper
A column flotation system was designed to conduct release analyses of a very finely disseminated, stratiform, copper ore from the Denali Copper Prospect, Alaska. Chalcopyrite is finely disseminated in a carbonate matrix and pyrite is disseminated in both the chalcopyrite and gangue, requiring grinding to 20 microns for adequate liberation. The ore is almost entirely chalcopyrite and pyrite hosted in
Grinding Circuit Expansion
Table of ContentsFinal circuit configurationSAG mill control Increasing ore hardness led to a gradual reduction of mill throughput rates. This, combined with declining head grades and low gold price, prompted a review of milling practice at Kidston. Plant trials and computer simulation of the grinding circuit indicated the potential to increase mill throughput by up to 45% by reducing SAG
Adsorption Behavior of Oleate
The adsorption behavior of sodium oleate on brucite, Mg(OH)2, has been studied by Fourier transform infrared spectroscopy. Both internal reflection and diffuse reflection (DRIFT) methods were used to characterize the adsorbed oleate on brucite. DRIFT measurements were shown to be quantitative, and an equilibrium adsorption isotherm was obtained. The conformational behavior of the adsorbed oleate was investigated as a function
Linear Systems Copper Heap Leaching
Chile is the world’s largest copper producer and as such sets the standard of practice in copper SX/EW design. The authors summarize the liner systems used at many of Chile’s major copper producers – both operating and planned. The evolution in the state of the art is also discussed, considering both economic factors and Chile’s burgeoning environmentalism. Unique Geo technical
Limestone for Sulfur Removal
Table of ContentsUsage for Flue-Gas DesulfurizatonDistribution of LimestonesPre-Mississippian LimestonesMississippian LimestonesPennsylvanian LimestonesPermian LimestonesMesozoic LimestonesCenozoic LimestonesSan Juan Mountains Southwest ColoradoAcknowledgmentsConclusions Reconnaissance sampling of high calcium (HC) limestones in New Mexico has been reported by Siemers (1982), Jicha (1956), and Kottlowski (1962). Numerous articles describe the limestone units in and near the state, such as Armstrong (1958) for west-central New Mexico, Mississippian and
Plug N Play Plants
Monometallic Flotation Plant Gravity Recovery & Au/Ag Leaching with CCD Merrill Crowe Plant & Refinery Gravity Recovery & Au/Ag Leaching – CIL Stripping & Refinery
Copper Bioleach using Thiobacillus and Nutrient Additions
A new bacterium, Thiobacillus cuprinus, can extract copper from chalcopyrite as rapidly as T. ferrooxidans. On solution with and without nutrient amendments and bacterial growth media were supplemented with T. ferrooxidans or T. cuprinus in shake flask studies. Both species extracted -42% of the copper using growth media. In one case, T. cuprinus solubilized approximately twice as much copper as
Elimination of Toxic Factors in Leachate – Biooxidation of Sulfide Ores
Toxic substances in On solutions can retard biological leaching of copper sulfide dump ores. On solutions were analyzed for metals, organics, and chloride, and showed inhibitory concentrations of aluminum, manganese, and chloride. Inhibition of bacterial activity by the solid fraction of On solution, with and without the organic constituents, was evaluated. Materials and Methods The most probable number (MPN) technique
Nitrate Concentrations Prediction in Tailings Effluent
The disposal of spent ore from cyanide heap-leach processing facilities is of concern to the mining industry, regulatory agencies, and the public. Disposal of several hundred million tons of additional spent ore is planned in the western United States during the next decade, with increased amounts likely if gold prices rise. In the past decade, more than fifteen million tons
Recover Silver by Gravity Concentration
In some cases, silver will recover very well by gravity. In laboratory testing, two kilograms of plant feed was ground to 80µm F80 and passed through a Falcon concentrator. The Falcon concentrate was panned to upgrade the concentrate and reduce the mass recovery to what is typically achieved by plant operations. A flowsheet and summary of results are shown in
Metals in Solutions – Dissolution Kinetic Modeling
Table of ContentsKinetic ModelDissolution Behavior of Cobalt in Iodine Iodide SolutionsTheoretical Approach A kinetic model for batch leaching of various metals with different lixiviants has been developed. Overall material balances for reactants and products at the solid/liquid interface were formulated with various types of heterogeneous reactions in place at the interface. The solutions to these mass balances have been identified
Laboratory Baffled-Column Flotation
Table of ContentsExperimental ProceduresSolids Free Tracer Tests The separating efficiency of a flotation column is largely limited by the degree of backmixing of tailings into the froth zone, and its recovery is limited by the degree of short-circuiting of feed to the tailings. Current columns are typically made very tall, on the order of 30-40 feet, in order to limit the
Gamma Flotation
Flotation is a well known surface chemistry-based particulate materials separation process which utilizes differences in wettabilities of solids. The operating mechanism in the process is that finely divided particles are rendered hydrophobic by the adsorption of suitable flotation reagents, so that they are captured by the rising stream of bubbles which collide with them. Particles adhering to air bubbles are
Remove Selenium from Water
Selenium (Se) is encountered in surface and groundwaters in the United States at concentrations that rarely exceed the drinking water standards (0.01 mg/L). However, in the western United States, leachates from heap-leaching operations at gold mines may contain selenium concentrations as high as 2 mg/L. In the gold heap leaching process, a solution containing sodium cyanide is sprinkled on the
AG & SAG Mill Grinding Circuit Automatic Control
It is obviously well understood that autogenous AG and semi-autogenous SAG mills operate quite differently from conventional rod mill or ball mills. Since these mills are of a grate discharge type, they operate with varying loads, with the power drawn by the mill being dependent upon the volumetric load within the mill and factors that influence the viscosity of the
SAG Mill Availability Targets
Table of ContentsGreat = 94%Exceptional 95% Keeping a SAG mill running well and “all the time” does not come easily nor does it come equally to everyone. “OK” = 90% Good = 92% Great = 94% Exceptional 95% Only one operation, located in Chile, is known to be at 95%. ** Thanks to Alex at SAGmilling.com for this intel.