Outokumpu is one of the world’s largest mill suppliers.Our grinding expertise combines the most advanced design, analysis and testing technologies to help you select the best mill for your grinding needs. A wide variety of designs is available to suit your requirements in either green-field projects or existing operations. As your partner, we provide the first key element of a total minerals processing solution. Grinding technologies stainless | copper | technology All are available in various designs and sizes in order to fully satisfy our customers’ requirements. Rod Mill Work Index (RWI) and Crushing Work Index (CWI) is necessary to determine the optimum mill design for a given application. Our state-of-the-art designs are developed from these years of experience – yesterday’s practical experience is used in today’s designs to produce premium technologies. product and materials behavior are also important considerations. separation. Our grinding mill range includes semiautogenous (SAG) mills. It is a factor our customers rely on to help them overcome even the most demanding challenges. dewatering and automation allows us to supply you with single units of equipment or turn-key deliveries to mining and industrial minerals plants. A deep understanding of parameters such as Ball Mill Work Index (BWI). Optimum mill type and size The correct sizing of grinding mills requires in-depth knowledge and experience in crushing and beneficiation processes. ball mills. we have inherited an established lineage of over 100 years from Morgårdshammar. to exact specifications. Our metallurgists and application engineers are acknowledged experts in these fields. All these brands are now incorporated into the Outokumpu Group. In grinding. 2 . Size distribution in feed.The key to successful concentration The Outokumpu factor The Outokumpu factor is the competitive advantage we give our customers by helping them enhance the performance of their processes. products and services. pebble mills and rod mills. a hidden asset that helps them win. Scanmec and Nordberg. autogenous (AG) mills. Solid grinding experience Outokumpu’s experience and knowhow in grinding. flotation. Spain. Trunnion-supported SAG/Ball mill circuit operating at Rio Narcea. from one size distribution to another.The first part of the sizing process involves standard application calculations. . In cases requiring additional data. Ore testing for that extra edge First-hand knowledge of the material to be processed is essential for the successful design and operation of any mill. Using our combined expertise in grinding and specially-developed sizing programs. we are able to make these calculations and recommend the correct mill type and size for any given application. Outokumpu has test facilities for material mineralogy and liberation analysis as well as complete minerals processing facilities at our own R&D center. we can rely on our close relationships with some of the foremost test centers around the world. at the specified feed rate. The calculations determine the power that must be applied to the mill in order to grind the ore. In grinding. there are dry processing applications for which dry milling is the necessary grinding method. 4 . AG and SAG mills are currently the industry standard for primary milling. Whether wet or dry applications. Rod mills Rod mills are mainly used for the primary grinding of crushed ore in the size range up to –50 mm for soft materials and –20 to 30 mm for harder materials and for the preparation of feed for secondary ball mills. Pebble mills are also used where the ore is capable of forming suitable pebbles. Ball mills are the secondary mills most often used in the preparation of the material for the following concentration process. where minimization of both processed mineral contamination and operating costs are of high importance. AG and SAG mills Autogenous and semi-autogenous mills are designed for primary grinding of run-of-mine ore or primary crushed ore. magnetic separation and leaching – are wet processes. a wet process is the most commonly used. The application range is similar to that of ball mills. we can provide you with the right grinding solution. as most of the downstream operations – flotation. Ball mills Ball mills are usually used for secondary and tertiary grinding. Shell-supported SAG mill operating in Mexico. These two types of primary mills are the most commonly used and we are highly experienced in providing the full size and power range right up to the very largest. Outokumpu can provide you with high-aspect or lowaspect AG/SAG mills to meet any milling requirement. Pebble mills Pebble mills are mostly used for secondary grinding. However.A full range of mills for wet and dry grinding The demands of hard-rock mining and industrial minerals operations require the availability of a wide variety of grinding mills. The journals are easily removable and bearings for both ends of the mill are identical and reversible. Due to the short trunnion. short trunnion length and simple lubrication. Spherical roller bearings are lubricated by means of a small motordriven or air-driven grease pumping system. The systems also deliver low-pressure oil at the edges of the sleeve to provide hydrodynamic lubrication for reliable. the bending moment on the head is small. The journal supports the trunnion surface through 120° of rotation. The journal or bearing sleeve material is either bonded white metal or centrifugally cast bronze. Low and highpressure standby pumps and standby oil filters are standard features of our journal-bearing lube systems. resulting in reduced stress and lower deformation of the head. Our capabilities and expertise cover both trunnion-supported mills and shell-supported mills. continuous. Different applications call for various mechanical configurations and designs. integral with the bearings. which accommodate the thermal expansion of the mill-rotating assembly. The housings (base and cap) are machined from steel plate. Both designs are complemented by an optimized drive solution. We offer mills supported on a variety of bearing arrangements: hydrodynamic and hydrostatic journal. Mill support bearings Journal bearings Journal bearings in Outokumpu’s trunnion-supported mills are hydrostatically lubricated during start-up and stopping as well as hydrodynamically or hydrostatically lubricated during operation. Our hydrodynamic journal-bearing lubrication systems deliver conditioned high-pressure oil at the sleeve center to lift the mill for start-up. Spherical roller bearings Spherical roller bearings can be used for mills with trunnion diameters up to 1. intended duty and environmental conditions at the installation site. Small reservoirs. The free (non-fixed) bearing is mounted on rocker-type pedestals.8 m. bidirectional operation. provide sufficient oil for the mill to be safely stopped in the event of a power failure. making them especially well suited to remote locations and harsh environments where routine maintenance is difficult. spherical roller. 5 .Mill designs for every requirement Our grinding mills are sized. Swivel support allows the bearings to self-align as mill loading changes. The benefits associated with spherical roller bearings are high loadcarrying capacity. hydrodynamic and hydrostatic multipad type bearings. designed and built for rugged duty and operation in the harshest of environments. selected for the exact conditions to be encountered. Mill bearings The type of support bearing is selected on the basis of the mill size. each pad is supported on a pedestal containing an integral hydraulic jacking cylinder and lock ring. and low-pressure oil is delivered to a slot at the ends of each pad to provide hydrodynamic lubrication for operation. These supports are machined from high-strength steel and fitted with a white metal bearing surface specially designed to suit the trunnion or shell diameter. Shell-supported mills Outokumpu’s shell-supported mills are more compact. Several individual pads are mounted onto the trunnions or shell at each end of the mill to provide a very high load-bearing capability and maximum tolerance of trunnion deformations. especially for indoor installations in severe climates and offers considerable cost savings.Multi-pad type bearings Large mills can be supplied with multipad type hydrodynamic or hydrostatic bearings. Each pad is mounted on a hydrostatically lubricated ball and socket support. This is an important advantage. As with our journal bearings. high-pressure oil is delivered to the center of each pad to lift the mill for start-up. occupy less floor space and require simpler foundations than comparable trunnion-supported mills. Shell-supported SAG mill and shell-supported ball mill operating in East Africa. . The jacking cylinder ensures easy alignment and equal load sharing between pads. To allow for rapid erection and alignment. Shell-supported open-ended SAG mill operating at Murrin Murrin in Western Australia. which results in lower forces acting on the mill structure. The overall span of the mill is less. away from the ends. where the journal surface is machined into the specially reinforced end sections of the shell structure. . mounted on to a flange. the feed and discharge openings may be sized to meet process conditions without being limited by bearing diameters. which in turn allows for smaller foundations and lower installation costs. A thrust surface is part of the fixed end journal and special hydrodynamically lubricated shoes are used to resist the axial thrust of the mill-rotating assembly. shell supports are being increasingly specified for very large. centrally located on the mill shell. heavily loaded mills. Because the end plates of the mill do not support the structure.Shell-supported mills are supported by bearings mounted directly to the shell. Our shell-supported mills use multi-pad type bearings. For this reason. The ring gear on shell-supported mills is normally Shell-supported pebble mill operating in Scandinavia. This enables the remaining components of the mill drive train to be brought closer to the mill. thereby yielding substantial advantages. The drive may be mounted at either the feed or the discharge end of the mill. The ring gear casting material is either nodular iron or steel. which makes them reversible. Mill drives Most mills are driven by ring gears. solid rubber. dual pinions are mostly used for mill applications above 6. Wave or lifter bar linings can be supplied. allowing the use of both flanks throughout their operational life. Large mills exceeding 13. High-speed motors require an intermediate gearbox.000 kW.The ring gears on shell-supported mills are placed away from the ends. Both high-speed induction type or low-speed synchronous type drive motors are available. Lining materials include unalloyed or alloyed cast steel. Whilst mills rated up to 10. usually with helical type teeth.500 kW normally use gearless drives. with a 360° fully enclosing guard. Mill linings Outokumpu offers a complete range of mill linings suitable for specific conditions. rubber-steel composites or ceramics. cast iron. depending on the application.000 kW can be driven by a single pinion. Smaller mills up to 500 kW are also available trunnion-driven. 8 . peripheral or open-ended discharge arrangements are generally only used for specific processes. rod and pebble mills are supplied with spout feeders and replaceable liners supported by a wheel-carried steel structure. a feed chute incorporating a “rock box” is usually provided. Ball. rod and pebble mills with This open-end SAG Mill (scrubber) at Murrin Murrin in Australia is lined with rubber. SAG and AG mills with openended discharge arrangements are more efficient than grate discharge arrangements.Feed arrangement For primary mills. such as overflow. to provide access for mill inspection and liner replacement. peripheral. SAG and AG mills typically have grate discharge arrangements with or without trommel screens. rod and pebble mills typically have overflow or grate discharge arrangements with trommel screens. Other available feed arrangements include screw-type. Large feed chutes can be supplied on wheeled carriages. Discharge arrangement We provide a wide variety of discharge arrangements. vibrating drum and scooptype feeders. Ball. grate and open-ended. which roll back away from the mill or roll away laterally on tracks. . Ball. Therefore. integrity and abrasiveness of the material. . costeffective technologies The selection of an appropriate mill configuration depends on the feed size distribution.Advanced design analysis Outokumpu mills are designed using the latest 3D computer-aided design (CAD) and drafting techniques. For mills utilizing journal or pad-type bearings. our lubrication design analysis predicts the minimum thickness of the bearing fluid oil film. effectively balancing capital and operating costs requires an experienced. the desired product size distribution and other physical properties which define the relative hardness. Our aim is to optimize your initial investment costs as well as the life-time operational costs. ensuring the mill operates at speeds away from harmonic frequencies. Designs are fully verified with the latest finite element analysis (FEA) tools and techniques. which predict peak stress levels in the mill structure and the ultimate life of the mill’s structural elements. practical understanding of efficient energy we and optimum mill life-span configuration. Energy-efficient. you contribute to energy saving and environmental protection. By applying our cutting-edge technology and solutions. Torsional analysis of the drive train can also be conducted. South Africa. This plan outlines the critical steps in the design and production process and lists the applicable documentation and physical inspections for each step. ISO 9001 certification. which is also the headquarters of our grinding business. Our specialists ensure that your mill is properly installed prior to commissioning and the process performance is verified after commissioning. USA. Smedjebacken. and Perth. Johannesburg. Once a contract is awarded. or have already received. which we maintain for the life of the installation. manufacture and supply. including complete mill reconditioning Complete process evaluations and performance diagnostics Liner wear measurements and profile development Maintenance inspections Alignment checks Gear reversals Service contracts Additional technical support is provided by our regional Grinding Business Centers. your local Outokumpu office provides: Ongoing support with promptly delivered replacement parts Other mechanical services. Quality assured Outokumpu mills meet the highest quality standards for design. Norway. Australia. We work in close co-operation with our global network of experienced. . Outokumpu mills are backed by our worldwide sales and service network. Regional business centers are either in pursuit of. qualified subsuppliers to produce the mill’s main components as close as possible to the installation site.Worldwide sales and service support To ensure premium quality product service and support. The results are recorded and form a part of the mill installation record. Sweden. After commissioning. Our Grinding Business Centers are located in Denver. a quality assurance plan is raised in the regional Outokumpu Grinding office. Engineers from our international mill business centers perform progress inspections to verify compliance with applicable specifications and standards. and Outokumpu’s global design office in Oslo. metal products. Outokumpu is a dynamic metals and technology group. April 2004. Libris. Finland. copper and technology. E-mail: info. technology and services worldwide. we aim to be leaders in all of our key businesses: stainless steel. Helsinki.outokumpu.com .3011EN. Customers in a wide range of industries use our [email protected] www. Focusing on our core competences. extensive knowledge of metals and metals processing. that is.