Ann: Investor Presentation, page-23

Whether the leach is CCAL or HPAL, you still put aluminium into solution via the leach process. HPAL drops some of the aluminium out as alunite, whereas CCAL keeps it all in solution. If you push the HPAL autoclave to a shorter residence time, you leave more aluminium in solution. The alunite precipitation process is slow.

Willis has a long history in nickel processing. He has been involved in some way with most of the major nickel laterite projects around the world. He has a significant role with both CLL and PGM and maybe even other consulting work.