Natives wanted a quick entry into the mining services by building an all
year air strip, However they were too quick about it and did so without a
permit. The government slapped their wrists by denying and probably will
just delay the permit. So the natives responded with a blockade of all air
services. This put pressure on the companies and from them onto the
government.
The fack that the blockade also served to get the government more involved
and in a more immediate fashion was also an incentive to block traffic.

As for Noront, of course they could have brought the big drills any time with big helicopters but they cost twice as much as a plane and they did not want to ruffle any native feathers.

I have no facts, just my opinion.