A silver liner-ing at a copper mine

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Despite having the world’s sixth largest copper deposit, Compania Minera Dona Ines de Collahuasi is facing the same issues miners are facing the world over: that of ensuring future productivity and overall viability.

As part of this process the operator instituted a new ‘preventive improvement process’, with the objective of detecting potential problems in advance to maximise performance and equipment availability.

Compania Minera Dona Ines de Collahuasi contacted Metso as part of this improvement effort to manufacture and mount of a new chute with four outputs for a 11’ by 11’ semi-autonomous grinding (SAG) mill.

“Pleased with the good results and the fact that all deadlines were met without any accidents, Compania Minera Dona Ines de Collahuasi decided to order three more chutes for the pebble stage,” Metso said.

“As a company we look for suppliers who can provide an integrated service that includes engineering, manufacturing, as well as assembly,” Manuel Vera, Compania Minera Dona Ines de Collahuasi’s asset management and reliability manager, said.

“Metso’s unique ability to offer an integrated solution was one of the key factors in the company’s decision to collaborate with them.”

Metso’s integrated approach consisted of several phases, beginning with the gathering of field data about the existing chutes in operation.

It turned out that the SAG mills needed improvement and that a liner change out was relatively challenging.

Additionally, the chutes were unable to absorb the full impact of the falling ore.

“All this added up to an insufficient flow, as evidenced by the large amounts of ore in the passageways and around the transfer chute,” Metso said.

“This excess material created premature wear in the conveyor belt and its support structure.”

These findings were passed on to the design, where they resulted in proposed improvements that were then validated through HFS simulations.

The design improvements aimed at reducing downtimes for liner change outs, increasing overall availability as less time is needed to schedule maintenance.

In addition, the new design included chute door systems for inspection and maintenance.

The integrated solution also included carrying out the actual liner change out and the assembly of the new chutes, as well as a follow-up on the performance of the liners and a continuous improvement plan for the transfer chutes.

Metso installed its extended wear life Trellex Poly-Cer solution, a modular system of ceramics and rubber, which provides increase resistance to strong abrasives – even with high tonnages at high speeds.

The new design of the chute liners makes maintenance easier by streamlining the change out of the anti-wear plates within each structure.

“Thanks to Trellex Poly-Cer’s greater resistance, it is typically up to ten times more wear-resistant than its steel counterpart,” Metso said.

The plates consist of ceramics (1400 HB) and rubber, providing both wear resistance and elasticity to absorb impacts.

As a result of these new designs, the service life of the chutes at Compania Minera Dona Ines de Collahuasi mine has increased.

“The original design required maintenance every 20 days or so,” Vera said.

“But now the interval is longer, and we know that optimisation of this can continue.”