MZI Resources (ASX:MZI) has released an updated ore reserve estimate of 58 million tonnes at 2.3% heavy minerals (compared to 72 million tonnes at 2.2% heavy minerals eighteen months ago). Based on the anticipated 5.25 million tonnes per year operating plan, the reserve-based mine life at Keysbrook is approximately 10-11 years. The total resource (which contains almost 147 million tonnes at a slightly lower average grade of 2%) remains open to the north, west and southwest.
The total reserves are indeed 14 million tonnes lower than the previous reserve estimate, and only 50% of that difference could be explained by mine depletion. Fortunately, MZI has provided a breakdown of the other factors which had a negative impact on the total size of the reserve. The two main factors were the removal of water exclusion zones from the reserve, as well as removing the oversized material. These two issues had a total impact of approximately 6.2 million tonnes.