The answer already exists and works on two fronts: increasing safety in changing mill linings and increasing availability by adopting a technology proven worldwide. We are talking about Metso's Megaliner, a coating with a large area of coverage, as it weighs 40% to 60% less than a conventional metallic coating. As a result, the number of pieces also decreases, because while a common coating would occupy 2m², the Megaliner can replace a 5m² piece.
Differentiated fastening system ensures safety
The Megaliner's safety starts with an inverted fastening system, ie the screws are inserted from outside the mill housing. In this way, they can be easily installed and removed with the aid of the hydraulic manipulator and are protected from ore slurry, corrosion and mechanical damage. When removing, the force of gravity is usually sufficient to loosen the coatings and there is even a specific tool to loosen the first row, complementing the process.
Another safety aspect is the presence of only the manipulator operator inside the mill, as opposed to changing conventional linings. Auxiliary maintenance technicians do not enter the equipment at critical times. They are therefore out of the danger zone while screws and plates are removed and installed. The manipulator operator acts in isolation. Features such as markers and an external camera system make it easy for the manipulator operator to position parts. Because the maintenance team remains outside the mill to remove, install and torque the screws, the technology provides better ergonomics and a better working environment.
Increased productivity with greater mill operational availability
In addition to the proven increase in liner replacement safety, Megaliner technology has up to 80% fewer parts (cladding and fastening components) than traditional systems. It also provides up to a 50% reduction in liner change time, increasing mill availability. In addition, the linings are designed to perfectly fit the curvature of the mill, protecting the equipment housing, preventing pulp penetration and running through the gaps.
Unlike conventional systems, the manipulator operator can visualize his work on the equipment screen and orient himself in relation to the alignment of the coating parts. Traditional technologies, in addition to greater manpower, need to move parts of up to 8 tons when changing coatings. The Megaliner, in turn, has success stories around the world that prove its efficiency in the field.
Commercial applications range from Chile to Sweden
In Latin America, Chile is the most outstanding example of Megaliner use, with a copper miner using the liner since 2013, showing benefits such as less weight, greater filling and use of the mill's installed power. And cumulative earnings of one million dollars per stop due to shorter trading time.
Two other Chilean mines also adopt Metso's technology. The first one has reduced the downtime for changing the coating by 12 hours since 2015 and avoids cutting screws, a common operation in the conventional system. In the second, in addition to all the gains mentioned, the decision to migrate to Megaliner was due to a stricter safety standard.
Outside Latin America, a Swedish mining company reduced the time to change coatings by between 40% and 50% by adopting the Megaliner, in addition to increasing the level of process safety. Another operation, also in Sweden, reduced the number of mill lining pieces by nearly 75% and the downtime for the changeover operation was cut in half.
In Ghana, Africa, a local mining company eliminated one of the annual shutdowns and increased the operational availability of its mill by 36 hours. There are also several cases in Canada, Australia, Finland, Peru and Mexico, among other places.