Background  

Imcor’s Barraba Silica Project will be sited at the derelict Woodsreef chrysotile mine, near Barraba in New South Wales. All that remains at the old mine site are abandoned buildings and some 110 million tonnes of waste rock and serpentinite tailings. By using the tailings and the waste rock, Imcor will turn the waste into value-added, specialty products. This will not only derive significant value from the tailings, but will remove the waste from the area and enable the site to be rehabilitated to meet current environmental standards.

The nature and proximity of the feedstock to the plant will allow Imcor to significantly reduce the costs usually associated with feed transportation and mineral processing. Imcor will have access to proven stockpiles of resource and therefore will not be required to mine. These stockpiles are made up of above ground tailings and mine waste. The tailings stockpile alone is sufficient for a project life of well over 100 years on the basis of forecast throughput.

Both the quantity and the composition of the tailings stockpile are known with a high degree of confidence, thereby eliminating the risk normally associated with the determination of mining reserves.

The Barraba Silica Project will produce silica, magnesium metal, ferronickel and magnetite by using commercially proven, Russian technology and other proven silica value adding technologies.

Silica value added products are used in applications such as rubber, tyres, food, healthcare, paints, paper and plastics. Some new specialty silica products such as silane coated precipitated silica are projected to grow at a rapid rate, particularly in the Asia-Pacific region. Magnesium metal has a wide variety of specialist applications including as a light weight “green” metal replacement in automobiles, and demand for the metal continues to grow. Ferronickel will also be produced as an intermediate product. By producing several high value products in one process, Imcor will be able to secure reliable returns.

A Conceptual Study has been produced as a platform on which to base a pre-feasibility study (PFS) which will be the next phase of project development. The PFS of approximately 12 months duration will commence on acquiring appropriate levels of funding. During the PFS stage, a number of engineering consulting organisations and laboratories will be engaged and overseen by Imcor’s engineering partner, WorleyParsons Ltd. A budget of A$3 million has been allowed for the PFS. A bankable feasibility study (BFS) is then scheduled to commence on completion of the PFS. It is estimated that the BFS will be finished within 2 years at a cost of A$18 million.

The Conceptual Study indicates that for a production of 35,200 tpa of silica products and 22,000 tpa magnesium metal, the project will show a robust internal rate of return of 29% and an NPV at 9% discount of A$430 million on an estimated capital cost of A$403 million.

Environmental Considerations

The Project will clean up an old tailings stockpile, process the stockpile materials into saleable products, and place any material remaining after treatment into an environmentally and ecologically safe and stable facility.

Imcor proposes to rehabilitate the site during the course of its operations.  This will involve:

  • Removal of all dump material and processing into saleable, non-hazardous products;
  • Placement of waste into a safe disposal site; and 
  • Removal of all buildings and facilities on the site at the end of operations.