Codelco El Teniente is the first mining company in the world to use Metso’s innovative grinding technology: the next level of Poly-Met discharge grates for SAG mills. Thanks to Metso’s grinding innovation and close cooperation between Metso’s experts and Codelco’s operations and maintenance specialists, in 2015 Codelco El Teniente achieved its all-time record for commercial production with substantially lowered operating costs. In 2010 Codelco El Teniente’s problems with grate piece breakage in their SAG mill resulted in low mill availability and operational instability. Codelco El Teniente worked in close cooperation with Metso to solve the problem. As a result, the next level of Poly-Met discharge grates were taken into use in a SAG mill for the first time. This innovative technology improves the copper production process by increasing the throughput and pebble production while also decreasing wear rate. The results have been impressive. In 2015 Codelco El Teniente achieved record commercial production of over 71 000 t of fine copper at one of the industry’s lowest cost levels. An increase in slot size and operational stability has increased throughput by 7 %. Pebble production increased by 24 % during the first 50 days of operation, while the wear rate decreased from 0.26 mm/day to 0.11 mm/day. Mill availability has increased thanks to the elimination of pinning and breakage. Codelco El Teniente also achieved historical results in safety in 2015 with an accumulated frequency rate of 1.
The Poly-Met discharge grates are made of metal and rubber, which means less weight and greater elasticity. The composite material was identified as the best solution for this type of application after a series of trials with Codelco El Teniente during 2012-2014. Metso is planning a global launch of Poly-Met grates in the later part of 2016.