Our Mining Process
Sibelco Australia is proud of its innovative and environmentally sustainable mining process. The following provides a step-by-step guide to our mining operations on NSI:
Long before any mining activity, we conduct pre-mine surveys, environmental monitoring and community consultation with key stakeholders.
We develop water management plans and vegetation and fauna surveys to monitor any changes to the local environment to ensure endangered wildlife and plant species are protected. Significant species which occur in the mine path must be re-established in the area after mining. Plant species which do not re-establish naturally are grown at our own plant nursery and planted by hand each year.
In addition, we use satellite imagery, aerial photography, ecological indicators and local knowledge to accurately develop complete vegetation profiles of our mine sites. This enables our rehabilitation staff to select the correct seed mixes and plant species for post-mine rehabilitation.
At Sibelco Australia, we also understand the significance of the Island’s Indigenous cultural heritage to the community. We work closely with the Island’s Minjerribah Moorgumpin Elders in Council, the Quandamooka Land Council and specialist archaeological consultants to preserve significant artefacts and community areas for future generations.
As part of the pre-mine studies, soil surveys are undertaken to gain an understanding of the soil’s chemical and physical properties. The findings are used by the company in managing soil resources, including the stripping and stockpiling of topsoil.
Prior to mining, vegetation is cleared and topsoil is stripped and stockpiled for use in rehabilitation or, where possible, soil is directly returned to areas ready for rehabilitation.
Dredging and Dry Mining
A floating dredge on an artificial fresh water pond uses a submerged rotating cutter to loosen the sand. Sand is pumped through pipelines to the floating concentrator at a rate of approximately 3000 tonnes per hour. Dry mining is the process used for supplementary feed to the dredge and for glass sands mining. Dry Mining Units (DMUs) optimise heavy mineral production and were introduced to the mineral sands operation in 2003.
The sand and minerals pass through the trommel which separates and discards large rocks and rubbish. In the concentrator, a gravity separation process using a series of water fed spirals separates the heavy minerals comprising rutile, zircon and ilmenite from the lighter sand. As the ilmenite contains iron, we then separate it from the rutile and zircon using WHIMS (Wet High Intensity Magnetic Separators).
The clean sand, from which the minerals have been extracted, is pumped behind the dredge pond and used to reform the landform as it is reshaped into dunes.
After transportation by barge from NSI to our dry mill located at Pinkenbar, near the mouth of the Brisbane River, the mineral concentrates undergo final separation.
They are passed through spirals and over wet separation tables and then kiln-dried before electrostatically separating the rutile and zircon. High-powered magnets then separate any remaining ilmenite from the rutile. Products are then packaged for transport to our customers.