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February 2013: Tenova TAKRAF Africa (formerly Bateman Engineered Technologies) is putting the final pieces together in completing an order for the supply of a 5.5m x 2.75m, hydraulically-driven SAG mill to Ontario Graphite, operators of the Kearney Mine located in Kearney, Ontario, Canada, about 300 km north of Toronto. This is the largest confirmed graphite resource in North America.
“Tenova’s scope of work includes the engineering, manufacturing, shipping and technical assistance during erection of the SAG mill’s feed end, shell, discharge end, drive and main bearings, as well as all supporting equipment (lubrication and jacking systems),” said Tenova TAKRAF engineer Pieter Van Der Walt. “The main hydraulic motor and rubber shell liners were outside Tenova TAKRAF’s commercial scope of supply, but inside its technical scope of supply,” he said.
The mill is a conventional SAG (semi-autogenous grinding) mill in all ways apart from its drive assembly and, it is centre-driven at the discharge end using a Hagglünds hydraulic motor and powerpack.
A graphic rendering of the SAG Mill that Tenova TAKRAF is supplying to Ontario Graphite’s Kearney Mine in Ontario, Canada.
“To date, this is the largest hydraulic motor installed on a SAG mill, with 950kW of power, torque of 1200 kN.m (start-up) and 650 kN.m (operational), and speed of 13.86 rpm,” said Van Der Walt.
Since the mill had to be retrofitted to an existing foundation, a number of adaptations were required to maintain the mill centreline, as well as feed-end and discharge-end positions. Certain additions were required to anchor the main motor torque arm.
“Centre-driving a mill at the discharge end brings significant challenges where the discharge of ground material is concerned,” Van Der Walt said. “The parts used to connect the motor to the mill trunnion have a dual function – to drive the mill and to discharge ground material. Exposure of structural parts to abrasive material must be avoided to ensure their integrity when exposed to high torsional loads during operation and, a special discharge/drive drum and protective liner were developed to counter possible abrasion,” he said.
“The SAG mill is the final and most valuable piece of the processing puzzle for us,” said Jerry Janik, general manager of Ontario Graphite’s Kearney Mine. “Delivery of the SAG mill marks a significant milestone in our path towards graphite production, and on top of the fact, that we’re reactivating a mine with already-proven resources and infrastructure, it gives us a tremendous advantage over any of our competitors.”
Tenova TAKRAF was awarded the contract to oversee shipping of all components to site. The Kearney Mine is slated to begin production in 2013.
About Ontario Graphite Limited
Ontario Graphite Ltd. is a privately owned Canadian mining company committed to the responsible re-commissioning and operation of the Kearney Mine, the largest confirmed graphite mineral resource in North America and one of the largest individual deposits outside China and North Korea. The Kearney Mine, located in Kearney, Ontario, Canada (approximately 300 km north of Toronto), is slated to begin production in 2013. To learn more about Ontario Graphite and the Kearney Mine, please visit www.ontariographite.com.
Tenova TAKRAF is a key supplier of equipment and systems for open pit mining & underground solutions and bulk handling, having provided hundreds of complete systems, as well as individual machines to clients all over the world in all climatic conditions. Leading-edge comminution systems for milling and crushing requirements in mining and mineral processing are based on a track record in mill supply dating back to the 1920s. Globally sourced air pollution control, specialised handling equipment, and technology for the cement and fly ash industries ensure selection of optimal processing options. A comprehensive after sales service is provided.
Tenova is a worldwide supplier of advanced technologies, products, and engineering services for the iron & steel and mining industries providing innovative, integrated solutions for complete process areas. More information is available at www.tenovagroup.com
