Metso Mining and Construction’s new Megaliner shell liner has been designed to reduce downtime for large grinding mills to a minimum, employing an innovative design that allows faster replacement. According to the company, it also improves worker safety during maintenance, as the liners are bolted into position from the outside of the mill and workers are not required to stand within the ‘drop-zone’ area of the liners.
Mill availability is improved through faster liner replacement. Megaliner, said Metso, uses larger than average liners yet these can still be placed with the same 6- to 8-axis liner handlers commonly used with large AG mills. Using larger liners means mills require fewer of them and Megaliner also has fewer attachment points compared with conventional liners, speeding up installation even further. Liners are easily and accurately positioned before bolting with the aid of highly visible, colored guiding markers.
Metso said it designed the system to make removal and replacement of liners as quick, safe and easy as installation. Bolting and unbolting is straightforward, as the threaded portion of the standard hex-head liner bolts is protected from dust, corrosion and general mechanical damage. Once loosened, it is often possible to remove the liner bolts simply by hand-turning them. Pneumatic or recoilless hydraulic hammers are not needed to dislodge worn Megaliners, as gravity alone is generally sufficient.
The Megaliner is suitable for large AG mills with large trunnions and where modern liner handlers are available. Each Megaliner element integrates multiple lifter and shell plate rows, and covers an area up to 4 m2 (43 ft2).
The rubber-and-metal composite liner weighs 30% to 60% less than metallic liners of a similar size.
Overall, said Metso, installing and replacing mill liners with the Megaliner system creates a much safer and less stressful environment for the liner handler operator and the installation team.
