Ore feed tonnage through the process plant increased by 2% with total throughput of 914,847t.
The front-end circuit continued to perform well, again achieving record throughput. The scrub efficiency has improved to 92.7% (against a design efficiency of 93%). As reported previously, optimisation work in the screening area in order to further improve performance is ongoing, with the classification section remaining the focal area of the optimisation efforts.
The extraction in the leaching circuit improved in line with expectations. This part of the circuit is now operating close to design parameters and the focus will be on improving throughput consistency to gain further extraction improvements and better management of reagents.
Although the efficiencies in the Counter-Current Decantation (CCD) circuit have been maintained, this area of the plant continues to have the biggest opportunity for further improvements. Additional modifications and improved operating procedures are being implemented, which should lead to further improvements in this area.
Modifications on both of the NimCix circuits have been completed and both circuits are now fully commissioned and operational. With both the NimCix circuits and the old Fixed Bed IX circuits available, further improved performance in this area is also expected.
The overall plant efficiency increased to 87.4% against a design recovery rate of 85%. The most significant contributor to this new record overall recovery rate has been the further improved leach recoveries. The improvement in the scrub efficiency also assisted whilst recoveries in the wash section remained consistent.
The detailed designs for TSF3 (the first full in-pit tailing deposition area) were completed during the quarter and construction work was commenced during this period. Tailings deposition is envisaged to change from TSF2 to TSF3 during the first half of CY2013. Construction of TSF2 and TSF2 extension also continued throughout the quarter.
Production Optimisation
During the quarter, an order was placed with Schauenburg MAB for the delivery of the first Hydrosort unit that will demonstrate the benefits of this technology to the beneficiation of the ore. This first unit is scheduled for commissioning at the end of the June quarter this year. Upon a successful demonstration, it is envisaged that at least one further Hydrosort unit will be installed to further improve ore beneficiation performance, reduce operating costs and increase resource utilisation.
There is also significant effort being directed toward the improvement of operating practice at the site now that the operation is consistently achieving nameplate and is in its post-commissioning phase. Material gains are expected as a consequence of these initiatives over the year.
KAYELEKERA MINE, Malawi (85%)
Production by quarter
---------------------------------------------------------------------------- Mar 2012 Qtr Jun 2012 Qtr Sept 2012 Qtr Dec 2012 Qtr --------------------------------------------------------KMU3O8 Production (lb) 724,552 726,299 638,950 772,280----------------------------------------------------------------------------
Production during the December quarter was a record, exceeding the previous quarter by 20.9%.
Mining
Mining data
------------------------------------ Sept 2012 Qtr Dec 2012 Qtr----------------------------------------------------------------------------Ore mined (t) 193,953 404,261----------------------------------------------------------------------------Grade (ppm) U3O8 1,065 1,814----------------------------------------------------------------------------Additional low grade ore mined (t) 145,328 63,201----------------------------------------------------------------------------Grade (ppm) 523 521----------------------------------------------------------------------------Waste/ore ratio 3.93 1.54----------------------------------------------------------------------------
