February 15, 2017 - As one of the world’s biggest copper ore operations, the Chilean mining company Compañía Minera Doña Inés de Collahuasi SCM based in Las Condes/Chile commissioned Siemens to modernize the drive system of four of its ore mills. The mine is located in the North of Chile, around 180 kilometers southeast of the port of Iquique. The contract required Siemens to supply drive systems comprising new motors and Flender couplings with torque limiting shear pin as well as Sinamics SL150 cycloconverters with thyristor stacks from its portfolio. The new drive systems are designed to boost reliability and consequently also the throughput of the mills. The contract is valued in the double-digit million range.
The modernization project includes two 8 MW SAG (semi-autogenous) mills and two 1.7 MW ball mills with dual pinion drives. The drive systems are replacing the existing synchronous motors and direct converters for the SAG mills and the drive systems of the ball mills, which were installed by a different manufacturer. The standardized system design now offers all the benefits of controllable drives also for the ball mills.
When implementing this project, to prevent costly standstill periods and also to minimize risk it was vital for the new motors to fit on the foundations constructed for their predecessors. Also with a view to minimizing any risks associated with the conversion, a decision was taken to replace the entire mill automation system by modern technology rather than endeavor the laborious task of adapting the hardware and software.
The direct converter and the automation systems were installed in ready- assembled new “E-Houses” which were completely developed, produced and pre- tested in the plant in Santiago/Chile, to be subsequently connected and commissioned on site.
The location of the mine at an altitude of over 4,200 meters meant that particular care had to be taken with the electrical and thermal dimensioning of components.