look at the website nadl, page-5

Angels, follow the link from Ingles on the NADL site -
http://nadl.com.au/press_clip.html

Scroll down to Broker Research.

I also had a read of this one back in 2006 which explains cinoo's question about reserves when Rio only mined 500k carats. It appears their technique missed a lot:
http://nadl.com.au/pdf/Minesite_NADL.pdf

"The latest work at Merlin, including changes to the way diamonds are sorted, has achieved a remarkable 41 per cent uplift in grade. “What we’re seeing is better liberation of stones, and better recovery in the sort house with nonfluorescing stones being recovered which were not previously caught,” Campbell said.
The enhanced recovery factor is one of the more interesting aspects of the re-awakening of Merlin. Under Rio Tinto management, recovering was largely by relying on the fluorescent property of diamonds under X-rays. “About 19 per cent of the population of diamonds from Merlin have a low fluorescence,” he said. “If they don’t fluoresce then they’re not picked up. What we’re doing is using optical and physical hand sorting to recover the stones which were previously missed.”

Chartwise it's a nice little jump this morning to break the short term down trend line from the 7.2 cents high. Hopefully I can put my edginess behind me now!