My recollections after being heavily involved in Aber and Diavik 15 to 20 years ago was that Aber had 3 pipes inside their constructed berm in Lac de Gras that averaged 3.8 carats per tonne.  Aber was so rich that when I got the core results in the fall of 1994 I was hyperventilating and salivating at the same time.  When a geologist does that, you know you have a rich diamond deposit!  But frankly, it does not matter.  Diavik's richness has been heavily depleted for the last 10 years.  Mountain Province and De Beers have currently the richest diamond deposit in Canada at 1.57 carats per tonne (possibly higher based in Tuso results).  1.57 carats per tonne in 3 sizable kimberlite pipes is money in the bank.  De Beers just has to complete the long process of environmental permitting and negotiations with the First Nations.  I believe this process will definitely get done, and everyone's patience will be richly rewarded.