Mineral processing methods are critical to the profitability of a mine operation, particularly as customers demand higher production, reliability, efficiencyand new features from processing equipment. Some of the most advanced technology in the world for crushing, grinding, washing and separating ores were showcased recently at the CIM Conference and Exhibition, held May 9-12 in Vancouver, Canada.
Among the 418 companies exhibiting at CIM — the most ever in the event’s 27- ear history, according to conference organizers—were some of the industry’s leading mineral processing firms.
In talking to these companies, Mining.com found that a common theme is the need to design equipment that is efficient not only in terms of production rates, but also with respect to power and water usage. Processing companies are also increasingly designing equipment with environmental factors in mind, as regulations around tailings and waste piles become more string Correcent.
These findings are supported by Mineral Engineering Technical Services, an Australia-based consulting group that recently outlined the coming challenges for the mineral processing sector.
The group says that technological innovation will be a major challenge for mineral processing companies as they seek to overcome barriers to profitability, including: tanking base metals prices; tightened access to capital caused by the financial crisis, and the potential for a carbon trading scheme which is expected to add to the cost of processing ore.
The imperative to reduce energy and water consumption is an equally important driver in the push to innovate, according to the group.
“Energy is a major cost for processing minerals and the comminution processes we use are inefficient and large consumers of energy,” says METS. The group forecasts a shift away from pyrometallurgical processing toward hydrometallurgical processing, and points to the long-overdue need for new grinding technologies.
On water inputs, METS also sounds a note of caution.
“Desalination as a water source for processing will become more common for projects… Water is going to become a scarceresource and access is going to be difficult with an emphasis on conservation and re-use.”
All of this points to an increasing emphasis on innovation to overcome the challenges faced by the global mineral processing sector. What follows is a picture of the mineral processing technologies presented at CIM.
W.S. Tyler
Hydro-Clean® is a high-pressure cleaning system from W.S. Tyler that separates fines between 0 and 80 mm from raw dirt material. The system is used primarily in gold, diamondand platinum mining, as well as sand and gravel operations.
The raw material is fed into a vertical drum, then washed by high-pressure (up to 2900 psi) jetsthat are fixed to a rotating washer head. The material is then discharged onto a horizontal vibrating screen with spray pipes, while the dirty water is processed through a water treatment facility or sent to a settling pond.
The system can process up to 400 tons of material per hour.
“We’ve been successful mainly in alluvial gold, diamond and platinum mining,” says Sam Palombo, vibrating screen and washing technology division manger for W.S. Tyler.
He says that with the current up tick in the markets for precious metals, Hydro- Clean is particularly well-positioned, with placer mines reopening and old tailings piles being reworked to recover the metals.
The system uses 75 percent less water than traditional washing methods such as scrubbers, logwashers and screw washers, says Palombo. Hydro- Clean also has a much lower retention time than older methods, with particles spending3-4 seconds in the drum versus 3-4 minutes in a log washer, meaning that less energy is being expended to wash each particle. “There are huge environmental advantages,” he says.
Metso Minerals Industries Inc.
The NORDBERG® MP1250 cone crusher and the SUPERIOR® 60-110E primary gyratory crusher arethe latest innovations from Metso Minerals Industries Inc. The NORDBERG® MP1250 features advanced crushing dynamics to achieve more work per cycle, an increased power draw of 1250hp, meaning up to 30 percent increase in capacity, and a higher power-to-production ratio, resulting in more efficient use of energy. The cone crusher is designed for minimal maintenance and reliability, with a sleeved eccentric machined to reduce wear and protect critical components in overload conditions. Fieldtesting on the MP1250 found that the cone crusher averaged a 29 percent increase in fine ore production over the MP1000, and reduced energy consumption by 10 percent or greater.
TheSUPERIOR® 60-110E primary gyratory crusher was redesigned to improve reliability. The arched Spider helps reduce material bridging. New arm shields and cap, utilizing a Rock Box design,protect the Spider.The redesigned Topshells eliminate vertical rib stress risers while utilizing horizontal bands to protect against concentrated loads. The single-piece Bottomshell reduces installation time, saving the mine operator money.
Xstrata Technology
The IsaMill® by Xstrata Technology is used for grinding in mineral processing including copper, lead, zinc, nickel, gold and platinum operations. It was originally designed for ultra-fine grinding down to 7 microns, but has since expanded to coarser applications. The horizontal configuration separates the fines from the coarse particles using a highly-efficient ceramic media. Due to the size of the ceramic media it has more surface area for grinding compared to steel media, resulting in more efficient fine grinding, explains Greg Rasmussen, Principal Metallurgist, Mineral Processing, with Xstrata Technology. Rasmussen says that IsaMills is replacing secondary grinding mills at an operation in South Africa, and he notes that a mine in Australia recovered 92 percent of 2-micron material.
Xstrata Technology’s Jameson Cell is a well-established flotation technology used in base metal sulphides, coal, industrial minerals, oil sands, solvent extraction and electrowinning applications. Improvements on the cell in recent years include improving wear with rounded components inside the header tank for smoother flow and adding rubber hose to replace metal piping for easier access. The cell has a number of advantages for the mine operator, including ease of maintenance (no moving parts) and high production capacity (3000m3/h) requiring minimal floor area.
“It’s very robust technology. It produces a very fine bubble which is great for fine flotation especially and, for your fast-floating material, it will recover it very fast, very easily, and can take it to final concentration grade in one stage,” says Rasmussen.
The IsaMill® by Xstrata Technology
DownerEDI Mining
Spiral and electrostatic separators, along with a new KAD (Kelsey Axial Displacement) Mill, were among the mineral processing technologies showcased by DownerEDI Mining.
According to the company, the Carrararange of electrostatic separators represents a new generation of separation equipment that includes high tension roll, electrostatic plate, electrostatic screen and tribostatic separators. The machinery separates dry, free flowing materials with particle sizes between 40 and 800 microns that exhibit electrical conductivity differences. Five series of spiral separators offer configurations in single, twin, triple and quad troughs per column to suit capacity requirements. The spiral banks up to 48 starts to maximize capacity and minimize floor space.
RPA Process Technologies
RPA Process Technologies built the firsthorizontal vacuum belt filtersystem, the Filtres Philippe belt filter, in 1948. The liquid filtration technology was born from extremely acidic and corrosive applications requiring long-lasting materials, says Rod Coombs, RPA’s regional sales manager for North America.
The belt filters are used to filter leached discharges from nickel, zinc, copper, lead and potash, as well as tailingsand oil sands. Theyare available in sizes ranging from less than one square metre up to 200m2.
Coombs says a key advantage is the fact that “The factory-spliced belt means it’s fully tested and quality-controlled before it leaves the factory, so there’s no issue of its being at the site having issues that cause delays,” he says. “Replacement times for belts are several months, which could be catastrophic on a plant’s schedule.”
Westpro Machinery Inc.
Westpro Machinery Inc. manufactures a variety of mineral processing equipment, from agglomerators, attrition scrubbers, conveyors and crushing systems, to flotation machines, grinding mills, hopper feeders and thickeners.
The company’s attrition scrubbers are used for mineral grain cleaning and polishing, liberation of minerals from slime coatings and disintegration of clay agglomerates. The equipment’s advantages include high-intensity and baffled zones, efficient impeller design, removable bottom liners and variable speed options. WestPro’s clarifiers are designed for sludge andmine dewatering, effluent and wastewater treatment, slurry and limestone transfer and fines removal. They feature a high-torque drive, variable speeds, forward and reverse, hydraulic or electric drive systems, high-efficiency rake design and a programmable local control system for automatic or semi- automatic operation.
Outotec
Outotec’s flotation and thickening technologies are utilized in mining operations throughout the world.
The company began manufacturing flotation cells in the 1960s under the “OK” brand, and now has specialized designs for various particle sizes. The heart of the cell is the mechanism that creates the bubble-particle interaction, along with its ability to efficiently recover froth. The Free Flow mechanism keeps the slurry in motion without excessive turbulence, while the Multi-Mix mechanism maximizes bubble and particle contact in the shear zone between the rotor and stator. The flotation units feature patented froth crowders to manipulate the froth and keep it in constant motion.
Outotec’s SUPAFLO® thickeners feature engineered feedwells, rake profiles, drive systems and control strategies to meet the challenge of dewatering problematic materials. The patented autodilution system minimizes flocculent consumption, thus lowering operating cost.
Multotec
Johannesburg-based Multotec offers solutions for screening and flotation, process equipment, solid/liquid separation, rubber wear, wear lining and conveyor belt fastening. The company’s HX5 High Capacity Mineral Spiral Concentrators are manufactured in single, twin, triple or quadruple starts. The 1000-mm-diameter units are rated between 5 and 9 tons per hour,and are ideal for treatment of low-grade ore requiring large tonnages for processing.
Multotec’s Two-in-one Sampler is for vertical gravity flow systems up to 4500 cubic metres per hour. It fits slurry lines from 4 to 36 inches, with high sampling frequency possible.
The Permax Wet Drum Magnetic Separator is for dense medium separation (DMS) plants, as well as concentration of magnetite iron ore, removal of magnetite from heavy mineral concentrates and removal of magnetite contaminants before flotation. The separator features a drum with a permanent magnetassembly, tank and drive unit. The drum is driven by a shaft-mounted geared motor, which eliminates maintenance and spare parts requirements associated with conventional chain or belt drives.
WesTech
WesTech’s paste thickening technology thickens a tailings stream to produce a paste, resulting in smaller tailings disposal volumes for mine operators and reduced water consumption.The company’s paste thickeners are most commonly applied to coal and iron ore tailings, as well as tailings from copper, diamond, gold, nickel, phosphate, uranium and aluminum.
WesTech’s thickeners work with various process tailings applications, including paste surface stacking, paste backfill and CCD (counter current decantation) circuits, whichthicken the material to a high density, requiring fewer clarifiers.
The technology can be seen as “an insurance policy against tailings dam failings,” an area that is being more closely watched by the U.S. Environmental Protection Agency, says Michael Gibson, WesTech’s dewatering sales engineer.
TEMA
TEMA Systems offers centrifuges for continuous liquid/solid separation, screens for separations, and mineral processing equipment. The company’s vibrating equipment includes horizontal, inclined and multi-sloped screens, dewatering screens, grizzly feeders, pan feeders, tubular feeders and grease tables. The Conturbex centrifuge is TEMA’s most versatile centrifuge; the solids retained on the screen are dewatered and transported to the largest diameter. TEMA’s horizontal coal centrifuge is designed with drive, gear and bearings away from the product stream, which prevents contamination damage to these parts and facilitates maintenance. The company claims 40 percent more drying power out of the horizontal centrifuge compared to vertical centrifuges.
FLSmidth
Market leader FLSmidth offers a range of equipment and technologies for mineral processing, including testing, design, engineering,crushing,grinding, classifying, flotation, thickening and clarifying, vacuum and pressure filtration, pyroprocessing, material handling, slurry handling, and automation.
As the world’s largest supplier of flotation equipment, FLSmidth is at the forefront of the industry trend to install fewer, larger flotation units rather than multiple smaller cells, which saves the mine operator s pace, power and maintenance.
The company’s 26 x 300m3 WEMCO® cells were the first cells over 300 cubic metres to be installed in a new plant, and the first used in rougher/ scavenger duty. The 350m3 SuperCell® Flotation Machine, the largest flotation cell in the world, will allow for interchangeable mechanisms to suit any application while handling more slurry per hour than normal cells.
ABB
ABB helps mine operators boost productivity and profits by managing operations and information more effectively. ABB’s gearless mill drives for SAG, ball and AG mills drive train components and offer a power range up to 35mw.
The company’s high power converters, variable speed drives, power distribution, process control, instrumentation and process optimization are used in agglomeration processes such as direct reduction of iron ore and refining non-ferrous metals.
Process control systems improve plant efficiency and productivity.
The OPtimizerIT Expert Optimizer increases production through better grind size, increased reagent efficiency and improved recovery.The InformIT Knowledge Manager provides important information for plant operations such as metallurgical accounting, mass balancing, process management and energy optimization.
