The zinc-lead-silver mineral resource at Lady Loretta ranks amongst the world's richest when measured in terms of in situ metal grades. However, the project remains undeveloped 28 years after its discovery in 1969. The primary obstacle to development has been the fine and complex grain structure of its ores, which make flotation concentration inefficient even with fine grinding. The size and remote location of the deposit have also hindered exploitation._x000D_
BUKA planned to directly fume the volatile target metals from the ore when it acquired the project. Intensive, post-acquisition modeling showed the innovative processing route to be uneconomic, notwithstanding high metals recovery and low waste content in fume product. Progressive modifications and supplements to the underlying fuming process enhanced economics and resulted in a new mine-to-metal processing route for zinc-lead-silver ores._x000D_
The proprietary, three-stage BUKA Zinc Process offers technical, economic and environmental advantages. It is expected to find widespread application in the treatment of ores and residues. However, neither continued R&D nor application to Lady Loretta's currently delineated resource can be justified under prevailing market conditions._x000D_
The objectives and results of each step in the process development sequence are outlined with reference to their impact on the commercial viability of the Lady Loretta project.