Comprehensive technological solution and successful results
The extensive upgrade of the equipment involved multiple steps. The Metso team first proposed improving the original design capacity by updating components and systems to produce some important benefits. For this, Metso focused on the main problems that were causing the structural misalignment of the filters. In order to solve the structural problems, the filter was completely disassembled and over 80% of its parts were replaced with new parts using a nanocoating technology for corrosive environments. Using this approach would double the lifespan of the key parts and components and reducing potential downtime.
In order to achieve the optimal selection of fabric, a pilot filter was implemented at the worksite to take samples of concentrate. The samples were then used to help define the proper fabric for the filtering process given the specific mineral conditions that Collahuasi was processing. In many situations, these types of tests involve using Metso laboratories located in Brazil and Finland. However, with the pilot filter on site, it was possible to perform all the tests in situ with the client, improving the selection and making it easier and quicker to get the results.
Another technological improvement introduced was the implementation OCS-4D, (an advanced process control solution). The solution assisted in determining the optimal control modes through analyzing the interplay between the selection of fabrics and maintenance events.
Finally, the chute was also examined for possible improvement opportunities. As the VPA filters discharge the filtered material (cake) into the chute, it was subjected to high rates of wear, causing a reduction in performance. Various designs and options were examined to improve ease of maintenance and thus reduce downtime.
“Searching for a design that improved maintainability, we implemented new, modular design upgrades to the chute, so that it could receive maintenance section by section. Thus, when a specific part shows signs of wear, we can disassemble that part and change it quickly. This is also an improvement that was tailored for the client, given that with the original design we had to disassemble the entire equipment to be able to change some parts,” says Alejandro Bravo, manager of Minerals Process Equipment.
Expansion of the project to all VPA filters
Given the success of the project, Minera Doña Inés de Collahuasi SCM is evaluating the implementation of the same upgrade concept in other VPA filters as part of its asset management plan.
“With this solution, we have been able to meet some of the availability goals we set for 2017. The filter today works according to the plans drawn up with Metso, which helps us to continue operating efficiently,” says Cristián Barros, senior engineer for Symptomatic Process at Collahuasi.
*Metso Outotec was formed July 1, 2020 when Metso and Outotec merged into one company. This case study has been written prior to the merger under the old company name.