Production
The processing plant continued to produce at nameplate design with production of 927,373lb (nameplate 925,000lb per quarter). The plant has been running consistently at Stage 2 rates since November 2009 and it is now evident the current levels of production can be sustained. All circuits are running to design capacity, with Ion Exchange remaining as the area of the plant with the most opportunity to further expand production. The previously reported low cost improvements in the Ion Exchange circuit were installed during this quarter. These are currently being optimised and improved recoveries are expected in this area of the plant during the coming months.
Production at LHM for the June 2010 quarter of 927,373lb was 34% higher than for the corresponding period in 2009.
Production for FY2010 at LHM was 3,352,251lb (FY2009 - 2,703,550lb), an increase of 24%.
Mining
Mining during this quarter showed some variance from the original mine plan as additional waste rock was required for the construction of the tailings facility TSF 2 wall. Processing was not impacted by this diversion of mining activity as the ROM pad had adequate stockpiles to meet plant requirements. Mining will return to plan upon completion of TSF 2.
Process Plant
Tonnage through the process plant has continued to increase during this quarter with a new record quarterly throughput of 548,018t of ore crushed.
The leaching circuits had a slightly reduced extraction rate of 93.7%. The insulation of the leach tanks is progressing well with 5 of the 8 leach tanks being completed (including the 2 bigger tanks). As a consequence reduced energy consumption is expected for the September quarter, compared to the same period in 2009. The insulation of the remaining 3 tanks should also be completed during the September quarter.
Counter-Current Decantation (CCD) is operating as expected. A campaign is underway to replace the underflow pump gland seals with mechanical sealed units and is continuing to reduce fresh water consumption and improving Ion Exchange performance.
Ion Exchange performance decreased slightly during the quarter, with the wash efficiency reducing from slightly above 80% to 78.9%. Two high priority projects reported previously have been constructed and installed during the quarter. The two projects, namely CO2 injection into the bi-carbonate solution and a system to remove resin from the fixed columns for cleaning to improve wash efficiency, have been installed and initial performance during commissioning has been encouraging. Optimisation of these components is currently underway and the improved performance in the wash efficiency is expected to be evident during the September quarter results.
The new dryer system is running well, with product being produced with very low moisture content.
Tailings
The extension to the TSF 1 was completed during the quarter. At planned production rates this will provide additional storage capacity until at least mid 2011.
The construction work on the first in-pit tailings facility (TSF 2) has commenced and progressed well during the quarter. Construction work on TSF 2 is expected to continue during the quarter and it is scheduled to receive tailings by the March quarter 2011.