Mobile plant pleases iron ore producers

Territory Resources? Frances Creek mine is located 220km south of Darwin, near the township of Pine Creek. The mine is located just 13km from the Adelaide-to-Darwin railway line, allowing easy access to the port of Darwin, Australia?s closest port to China.

A number of iron ore pits operated from 1966 until 1974 at the old Frances Creek mining centre, but were closed after flooding and the damage to infrastructure caused by Cyclone Tracy. Production at Frances Creek recommenced in May 2007. In September 2007, the first iron ore shipment for more than 30 years from Frances Creek left the Port of Darwin.

The global demand for iron ore remains strong, driven by steel production from China and improving demand from other major economies, including the emerging markets in the Indian sub-continent. Frances Creek Mine provides Territory Resources with a high quality product, quality exporting infrastructure and close proximity to China through the Port of Darwin.

In 2008, Territory Resources decided to increase its existing supplementary mobile crushing plant. The age and condition of the existing plant meant maintenance issues were all too common.

Territory Resources contracted Barminco Limited, a large Australian underground mining contractor and contract crushing company, to carry out this work. Barminco was selected for the project on the basis of being able to fulfil the large demands of the contract. Barminco offered the Metso mobile crushing plant on the basis of reliability and the ability to handle the density of the product. The selection of these machines required a lot of discussion between Barminco, Screenmasters (Metso?s Australian dealer) and the original equipment manufacturer, Metso (Australia) Limited, who were able to supply the equipment required. The product support offered was critical to the selection of the equipment.

In March 2010, the crushing plant began operation. The Metso plant, purchased through Screenmasters, consists of a Lokotrack LT3054 mobile jaw crushing plant, two Lokotrack ST620F mobile screens, each equipped with a FS303 triple deck horizontal screen, and a Lokotrack LT300GPS mobile cone plant.  

Barminco is operating under a two year, two million tonne plus per annum contract. The demand for product to satisfy the contract requires maximum plant availability. ?Currently all crushed product being produced is sold, so minimising downtime and maximising output is vital,? states site manager Peter Stewart.

The iron ore source, although hard, is not abrasive but, due to the tropical conditions, the moisture content in the ore varies greatly. This affects daily production as different grades of the feed are required to fulfil the requirements of the contract.

The feed to the LT3054 mobile jaw crushing plant is minus 700mm, and is reduced to minus 150mm, with scalps of minus 8mm taken from under the jaw screen. The ST620F mobile screen follows the LT3054 with screen meshes of 40mm on the top deck, 25mm on the middle deck and 8mm on the bottom deck. The LT300GPS mobile cone plant follows with a close side setting of 32mm. The two final products are a lump (minus 40mm to 8mm) and a fines product at minus 8mm, both of which are exported to China. ?The minus 40mm and minus 8mm product specification grading is critical and the end customer requirements are such that out of specification product would be not accepted,? says Peter.

Production at the site can be higher than 400 tonnes per hour. The plant has the potential to produce more than 8000 tonnes per day, with consideration to maintenance. At times, the plant operates 20 hours per day, over two shifts, with four staff on each shift. Two hours are allocated daily for general maintenance and start-up. On-site servicing is available, and is carried out between shifts when required.

The plant had been running for three months at the time of the visit. ?Things have been going well, producing a quality product; we are very happy with the plant capacity and capabilities. Wear on parts has been minimal, considering the product weight factor, the crusher parts are still pretty new,? Peter adds.

The new mobile plant has many significant benefits over the old fixed plant. The LT3054 jaw plant has a VG527-2V and PF525-2V pan feeder which has helped in separating the wet scalping fines from the feed material. This had caused problems in the past. The scalper feature of the Lokotrack LT3054 reduces the fines going through the circuit. The coarser product has helped increase production. Achieving the correct reduction and final product size is very important. Depending on the screen settings, any material over 40mm is recirculated. The LT300GPS cone crusher has its own screen and oversize belt, allowing it to separate its own oversize feed.

?The auto stop feature for the feed control on the cone is very useful. If the cone stops, the rest of the plant stops as well,? says Nksona Danai, who is responsible for service and maintenance of the plant.

The working platforms on the crushers have also received positive comments. All service points on the LT3054 are easy to access, and a service platform is located below the vibrating grizzly for easy screen mesh replacement.

?Changing side belts is also easy, because they are movable. There is flexibility to move belts and conveyors to suit the set-up of the plant,? explains Nksona.

Peter Small is the Metso dealer business manager. Scott Parsonage is a member of Metso?s marketing support team.

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