The fact that no other significant deposits have (so far at least) been found near Degrussa doesn't necessarily mean that the Nova style deposit won't be one of a cluster. Likewise for Rocklands, though in that environment you could argue that there are numerous significant deposits (Mary Kathleen, Ernest Henry for a start).
If you hold the view that there won't be any further discoveries in the Fraser Range based on the Degrussa and Rocklands examples, then you won't be holding any of the other players, especially at the current market caps. On the other hand, if you look to the likely type precedent of the Thompson Nickel Belt in Canada you will see that those deposits do occur in clusters with (I think) eight deposits so far having been located - Thompson, Pipe I, Pipe II, Birchtree, Soab, Manibridge, Bucko and Bowden.
With respect to age, it is interesting what Porter Geoconsultancy has to say about Thompson. "The Thompson nickel deposits are located within the Thompson Nickel Belt of northern Manitoba, Canada. This belt lies on the margin of the 1850 Ma Trans-Hudson Orogen, adjacent to the north-western margin of the Archaean Superior province."
1850 Ma is firmly within the Proterozoic age which ranges from 541 Ma to 2500 Ma, Archean being from 2500 Ma to 3800 Ma. Knowledgable geologists might comment, but on my understanding, you could say that the Nova "belt" lies in the Fraser Range mobile zone, adjacent to the south-eastern margin of the Archean greenstone belts in WA.
Porter goes on to say: "The total production plus reserves in the Thompson Belt amounts to approximately 89 Mt @ 2.5% Ni, 0.13% Cu. Proven + probable reserves in 2005 were: 25 Mt @ 1.9% Ni. The total estimated resource (including production) at Thompson is estimated by Naldrett 2004 as 150 Mt @ 2.32% Ni, 0.16% Cu, 0.046% Co."
The Porter Geoconsultancy information is from http://www.portergeo.com.au/database/mineinfo.asp?mineid=mn173.
