Mining Magazine > Panorama > ABB to deliver three large gearless mill drives for Mauritanian gold mine project

ABB has announced that it recently won a contract from Kinross Gold Corporation for the delivery of three gearless mill drive (GMD) systems to be installed at the Tasiast gold mine. Tasiast is an open-pit operation located in north-western Mauritania, Africa, situated approximately 300 kilometers north of the capital Nouakchott. The three ABB GMDs are part of an expansion project scheduled to go into commercial operation in early 2014.

The Tasiast open-pit mine will feed both an existing 8,000 tons per day plant and a new 60,000 tons per day plant. The existing Tasiast mine began commercial operations in 2008. The expansion plant is a conventional gold cyanidation plant, consisting of primary crushing, grinding, gravity separation, carbon-in-leach cyanidation and cyanide destruction.

ABB’s scope of supply consists of three complete GMD systems including transformers, ring motors and E-house. One 26 megawatt GMD system will be installed for a 40-foot diameter SAG mill, while two 20.5 megawatt GMD systems will be installed to drive two 27-foot diameter ball mills. In addition, Kinross ordered the new ABB GAP-Watch for each system. GAP-Watch is a unique rotating air gap monitoring system for ring motors. This latest ABB GMD innovation is designed to constantly measure the distance between a rotor pole and the stator of the ring motor (air gap) while the mill is rotating. The measurements provide a real-time picture of the air gap along the complete circumference of the motor, leading to increased reliability of the GMD system.

As a variable speed drive, the GMD allows the mill to start smoothly, without any mechanical stress, and fulfills the customer’s requirements for flexibility and adjustability of the process, enabling maximum control over the grinding process. Furthermore, ABB gearless mill drive systems feature several benefits when compared with conventional geared drive systems: superior reliability, availability, extended life span and improved energy efficiency. ABB delivered the world’s first gearless machine drive in 1969, which is still operating at the Ciment Lamberg-Lafarge cement plant in Le Havre, France.