Stalling (mineral, iron, wood, etc., caught in its crushing chamber) and the fact that the units had to go into maintenance for long periods of time without warning; these issues ultimately led to lower production.
The time associated with operational adjustments to the equipment, such as its close setting, which had to be carried out at least twice every shift. This generated complications due to its older configuration, which involved a piston rack and, for each adjustment made, caused a 30-minute interruption (on average) to the process. This interruption added up to 2 hours of lost time a day (corresponding to 8.3%).
Today, after the upgrades were carried out, they are still adjusted twice per shift, but the daily impact is only 20 minutes a day, i.e. an increase of 7% in the equipment’s usage.
The third factor was the scheduled maintenance every 4,500 hours; it was time-consuming due to the fact that these older-generation Symons 7’ units have an outdated spring system that doesn’t allow for quick maintenance and the ready freeing of the crushing chamber.
This problem is common to all mining plants with older-generation equipment. In Chile, there are more than 100 such units operating in different mining plants.
Increased equipment availability and lower exposure to risk for the workers
In light of the above challenges, Metso fully re-engineered and improved the equipment and installed cutting-edge components. “Starting in 2015, a project was carried out to modernize the famous and historic Symons equipment. Its mechanical components and adjustment system were updated, its springs replaced, and the ring adjustment operation automated, which led to the upgrade proposal for the current modernization,” Metso’s Mining Crusher Screens manager Nelson Mella pointed out.
For this particular Symons 7’, modern systems to free up the crushing chamber were used; in terms of securing the chamber, the older Symons technology was upgraded to HP and MP technology.
“By doing this, the advantages include increased equipment availability, lower exposure to risk for the workers, and better product quality control, as the setting can be adjusted more accurately as a result of the motorized setting,” Mella points out.
In addition, a new Hydraulic Power Unit with a PLC was installed, enabling Ethernet connectivity for the existing automation systems belonging to the client or through Metso automation systems (e.g. TC1000, TC2000). This makes it possible to adjust parameters remotely, optimizing the equipment’s efficiency.
The solution was installed by the client over the course of one week in June 2018 under the guidance of Metso professionals. The results:
A 31% increase in availability, thanks to less time needed to adjust the unit’s bowl and Closed Side Settings.
A reduction in maintenance time and, consequently, a reduced risk of injury. This was achieved by replacing the spring system.
The equipment’s setting time was reduced (from 30 minutes to 5 minutes).
The bowl removal time was reduced (from 3 hours to 25 minutes), and the adjustment ring removal time was reduced (from 10 hours to 3 hours).
*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.