Yes, roads are a key for this development. The stock price will most likely go up significantly this year in spite of this issue, as more positive drill results come in. I guestimate that about 250 km of pretty heavy duty roads have to be built to bring out about 300,000 tonnes of nickel concentrate per year, in order to allow transport to a smelter. If the cost of this is less than 100 million, then thats just peanuts, if significantly more then it is more of an issue. To build such roads(plus bridges) will take a loooong time, which makes it hard for a major to spend money now taking over all the small players while having to wait a long time to start making money.
It is a little 'strange' that a diamond company finds this potentially extremely nickel rich region. It may be that since such companies(as well as gold miners) have such valuable products(diamonds and gold) air shipment is not at all an issue. They may therefore look in regions where traditional base metal companies normally would not look due to head aches with shipping products. This may suggest that there is still lots more in the broader region that has still not yet been discovered.