How about a little and simple arithmetic:
2% nickel = 20Kg/ton(44lb.) of ore @$5/lb = $220.
4% nickel = 40Kg/ton (88lb.) of ore @$10/lb = $880.
Any way you cut it a ton of ore can not cost more that $50 to process so subtract that $50 and what have you got?
A ball park range of about $170 to 800 per ton of ore in value. Reason enough to be excited about.
Even at 2% concentration, if the resource and metal price is not large, you still have a potential mine Because it would be Profitable.

So the question remains - How confident are you that there is at least 2% nickel in that ore?
Do not trust hand held instruments? Ok.
Company says there is no material evidence. Ok also.
Trade volume is based on hype. Very likely.
It makes no sense to quibble over who said what and due to what. Caution is warranted. So don't fret, you will know soon enough. Just do not regret when you eventually do know.

However, if you believe that hand held field instruments are a fair indicator, companies must say the politically correct thing or deliver the goods ( What else can they say when the goods are not ready?) and finally that a large segment of the trading population assumes fire when there is smoke, then you have no choice but assume that there is some substance to the rumours. Just do not get too hung up over the details or lack of.

Stock investing is just another form of gambling ( more socially acceptable and respected than the common variety ) but like any gambler you hedge your bet if you can.