Located near Leonora in the Eastern Goldfields of Western Australia, the Sinclair nickel deposit was discovered in 2005 by Jubilee Mines NL. Initial exploration indicated the potential for a significant nickel sulphide system that culminated in the go-ahead for a new mine to be constructed in 2007.
Belmont based GR Engineering Services (GRES) were approached by Jubilee Mines to prepare a proposal for the construction of the mine, and according to GRES Project Manager, Steve Kendrick, time was of the essence. Following acceptance of our proposal GR Engineering Services was appointed to undertake the engineering, design, procurement, construction and commissioning of the new 300,000 tonnes per annum process plant’s facilities and associated infrastructure.
REQUIREMENTS
Flexibility was the key to our proposal as the process plant had to be designed initially to handle a supergene ore blend during open-cut mining and then a primary ore blend when mining moved underground. In essence, the contract called for blended ore to be processed through a conventional crushing and grinding circuit followed by a sequential flotation of the nickel minerals, with the run of mine (ROM) pad managed to get adequate blending of the ore prior to processing. The plant consisted of a ROM ore storage, single stage jaw crushing and crushed ore stockpile, primary grinding using a SAG mill – or semi-autogenous grinding mill, flotation and concentrate re-grinding, concentrate thickening, filtration and storage, tailings thickening, disposal and water return, reagent mixing, storage and distribution, and ancillary services that included water and air.
GRES commenced engineering, design and construction of the process plant facilities in September, 2007 and completed the project on schedule some 13 months later in 2008, despite considerable pressures on labour and equipment supply from high levels of industry activity during this time.
As the contract included substantial performance guarantees, aspects that were critical to the plants performance were evaluated thoroughly – like the transformer / motor / drive package for the SAG mill.
During the planning and design phase we looked at various drive / motor / transformer packages from all the leading suppliers, but ultimately decided on the WEG package as we believed they had the best technical proposal that reflected the approach we wanted to take with the supply of the equipment.
WEG’s ability to supply a 1 Megawatt motor for the SAG Mill in their turn-key package was also an important factor as the motor was a critical part of the overall performance of the plant. At the end of the day, if the SAG Mill didn’t perform on commissioning we would have had serious problems.
During our initial discussions WEG demonstrated a conservative approach in specifying the appropriate package to ensure the mill would perform to the specifications, and while some of the other supplier recommended cheaper solutions WEG’s approach suited us best for optimising the performance of this critical piece of equipment. And following installation the standout feature for us was that the WEG package worked as required, handling the starting load power requirements of a fully loaded SAG mill. So when the mill started smoothly it was a significant milestone in fulfilling our contractual obligations.
Overall WEG’s performance during the entire process was excellent. Feedback from our staff involved during the tender process was that WEG provided the most technically compliant proposal, while their technical support during installation and commissioning assisted with a smooth transition to plant operations, Steve said.
Commenting on the Sinclair nickel project WEG’s Western Australian Sales Manager, Renato Gualda Karavasilis, said that WEG Australia’s ability to provide a complete transformer, motor and drive package in a short timeframe and then support it locally out of Perth was a critical factor in being awarded the contract. WEG Medium Voltage Drives incorporate cutting-edge technology with 6.5kV rated IGBTs and OPP modulation. With the lowest count of Power semiconductors of all drives, it is the most efficient MV inverter available on the market, achieving 99% efficiency and delivering one of the longest mean time between failures. With the WEG package GRES were able to offer the mine’s operator some unique processing innovations which have greatly enhanced productivity and life expectancy. We understood the critical nature the transformer, motor and drive package would play in the overall project from the outset and tailor-made the appropriate turn-key solution that we installed, commissioned and guaranteed, Renato said.
ABOUT GRES
GR Engineering Services is an engineering consulting and contracting organisation providing high quality process engineering, design and construction services to the resource and mineral processing industry. GRES focus on providing integrated, efficient and practical designs to achieve high quality, cost effective solutions, while maintaining a high level of safety and operational performance to successfully deliver projects. GRES personnel have the capability and proven track Record to undertake projects from the initial evaluation and study phase through to design, construction, commissioning and operation support.
