The Redross orebody averages 1 m wide, has a strike of 50 – 350 m, dips at 55° and has a basalt footwall and an ultramafic hanging wall. The most successful and innovative aspects of mining Redross were:
•ore development innovations, 90 per cent of development was split fired with a shanty back profile to enable larger and more productive equipment to be used and resulted in higher development grades, improved project payback time and improved ore recovery;
•hand held stoping using a multiple level, bottom up ‘V’ shaped hand held stoping method that allowed mining on multiple levels with hand held productivities between 50 and 90 tonnes per shift;
•the use of 1 m cement pillars and 7 m high crown pillars were used to create multiple mining areas that enabled high overall production rates from hand held mining this orebody; and
•the use of vertical cement pillars to enable hand held mining of adjacent stopes without leaving ore pillars.
The Mariners orebody averages 3 m wide, has a strike length of 50 – 250 m and dips at 50° with a basalt footwall and poor ultramafic hanging wall. The most successful innovative ideas of
re-opening Mariners were:
•Dewatering the existing mine workings utilising ‘oilfield’ technology by installing a long submersible pump in on existing pump rising main. This enabled the mine to be dewatered at rates up to 100l/ sec and helped overcome the 45 to 55 L/s inflows.
•Overcoming the technical problems associated with Mining N07 ore blocks which had severely deteriorated from being underwater for five years by using reverse firing techniques to improve extraction rates and reduce dilution.
•Mass firing a large mining block in the N08 with minimal void space because of deteriorating ground conditions.
•Use of a longhole version of the Redross hand held mining method to achieve 100 per cent extraction of the N09 higher grade lenses.
Will, D and
Poepjes, M, 2011. Mining at the
Redross and Mariners nickel mines, in Proceedings 11th AusIMM Underground Operators’
pp 167-178 (The Australasian Institute of Mining and