WA – The Roy Hill Iron Ore Mine Development
The development of the Roy Hill Iron Ore Mine is proceeding at a fast pace and is due to commence delivering 55 million tonnes of ore per annum in September 2015. Work on the rail and port facilities is proceeding on schedule.
However, of particular interest to ANCOLD members, the construction of tailings storage facilities, flood levees and diversion structures is proceeding at a rapid pace.
The Tailings Storage Facility (TSF) is required for the deposition of tailings from the ore concentration process. The annual production of tailings is planned to reach 13.3 million dry tonnes per year and the TSF was designed to contain tailings for the first ten years of the mine production. The TSF was designed as a conventional paddock style facility with perimeter tailings deposition and a central decant system, which covered an area of more than 300 ha and included almost 8 km of embankments.
To allow for continuous development of the facility without interrupting the tailings deposition, the TSF was split into two cells. Each cell can be raised independently while the other cell is being used for tailings deposition. There will be seven consecutive raises above the initial TSF embankments, before the ultimate storage capacity of the TSF is reached. The initial TSF embankments contained almost 2 million m3 of fill, borrowed locally from within the footprint of the TSF. The TSF embankments were designed as essentially homogeneous structures allowing for high construction production rates.
The maximum construction rate achieved was almost 20,000 m3/day of placed and compacted fill per day. In order to maintain high construction rates, four construction crews of five or more scrapers and two compactors each, were operated simultaneously. Night shifts were introduced to allow for conditioning of the borrow materials. .The construction of the initial TSF embankments was completed on time in early 2015.
The other civil infrastructure includes over 14 km of levees and drains. The highest of these was the 10 m high levee that diverted the flows from Kulbee Creek into the diversion channel. Designed to pass the 1:1000 Annual Exceedance Probability flood of almost 600 m3/sec down the channel, the levee structure contained almost 50000 m3 of fill.