Integrated Annual Report 2015
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Business Model 
Operational review – Mimosa

“Steady-state platinum in concentrate production at Mimosa will be maintained at around 100 000 ounces per annum

 

Mimosa – the joint venture shared equally with Aquarius Platinum – remains one of the safest operations in the Implats stable and delivered another excellent operational performance.

Manufactured capital

Mimosa’s total injury frequency rate improved to 0.39 from 1.79 per million man-hours worked in 2014.

Operations at Mimosa remained efficient with steady-state throughput and production exceeding the previous year. Tonnes milled improved by 5.4% to 2.59 million, head grade was steady at 3.93g/t, while concentrator recoveries improved to 78%. The increased throughput together with improved recoveries increased platinum in concentrate production to 117 400 ounces, 6.5% more than the previous year (2014: 110 200 ounces).

Financial capital

Unit costs benefited from the higher volumes as well as a cost rationalisation programme and decreased by 11.0% from US$1 713 per platinum ounce in concentrate to US$1 525. Capital expenditure of US$30 million was spent mainly on underground equipment, conveyor belt extensions and development towards the Mtshingwe block.

The imposition of a 15% export levy on unbeneficiated platinum concentrates in Zimbabwe, which became effective from 1 January 2015, would have had a material impact on the profitability and sustainability of this operation. Active engagement with the government of Zimbabwe was initiated to highlight this risk. The levy has reportedly been suspended for two years to allow mining companies to meet beneficiation requirements in the country. Mimosa is in discussions with other producers with regard to co-funding a smelter in the near term.

Mineral resources and reserves

For more detail refer to the “Mineral resource and mineral reserve statement 2015” available at www.implats.co.za.

The Mimosa Main Sulphide Zone mineral resource statement reflects changes due to additional assay results, updates to the geological model and depletion due to mining over the past 12 months. Notably, a larger part of the mineral resource has now been upgraded into the measured category. The mineral reserve estimate for Mimosa has been materially impacted by the inclusion of a large part of the Mtshingwe resource block in the mineral reserve category, following the approval of the mine plan and capital expenditure.

     Mineral resources inclusive
of reserves  
2015   2014  
       Orebody   Category   Tonnage  
Mt  
6E  
Grade  
Pt  
Moz  
Pt  
Attr  
Moz  
Tonnage  
Mt  
6E  
Grade  
Pt  
Moz  
Pt  
Attr  
Moz  
  Mimosa (50% attributable)     MSZ   Measured   69.2   3.91   4.1   2.0   53.4   3.97   3.1   1.6  
     Indicated   31.2   3.79   1.8   0.9   43.4   3.83   2.5   1.2  
     Inferred   27.1   3.66   1.5   0.8   32.4   3.83   1.9   0.9  
       Total      127.5   3.83   7.4   3.7   129.2   3.89   7.5   3.7  

 

     Mineral reserves   2015   2014  
       Orebody   Category   Tonnage  
Mt  
6E  
Grade  
Pt  
Moz  
Pt  
Attr  
Moz  
Tonnage  
Mt  
6E  
Grade  
Pt  
Moz  
Pt  
Attr  
Moz  
  Mimosa (50% attributable)     MSZ   Proved   22.9   3.79   1.3   0.6   10.5   3.72   0.6   0.3  
     Probable   10.9   3.96   0.6   0.3   12.1   3.50   0.7   0.3  
       Total      33.8   3.84   1.9   1.0   22.6   3.60   1.2   0.6  

The key features of the above updated statements are:

  • The Mimosa Main Sulphide Zone mineral resource estimate decreased by 1.5% to 7.4 million platinum ounces mainly due to mining depletion
  • The Mimosa mineral reserve estimate increased by 55% to 1.9 million ounces due to the conversion of a large portion of the Mtshingwe block to the mineral reserve category.

The updated Mimosa life-of-mine profile includes the two South Hill areas only – Wedza and Mtshingwe shaft blocks. The profile indicates that production output – at some 2.6 million tonnes per annum – can be sustained until the 2029 financial year from the combined infrastructure. The life-of-mine profile excludes the potential increased output by some 30% through a possible future upgrade of the processing capacity. This is the subject of ongoing studies. Additional areas, such as North Hill, could supplement and potentially extend the Mimosa production profile in future years.

Outlook

Mimosa is expected to continue its excellent performance and steady-state platinum in concentrate production will be maintained at around 100 000 ounces per annum.

The mine is in discussions with other producers to co-fund a smelter and studies are currently under way in this regard. A detailed feasibility study to evaluate the potential to increase production will be completed early 2016.