Re: the roads in to the drill site and surrounding - there are plenty of roads around the area that heavy vehicles frequent. Towards the north - since the war ended - it’s been a building site, a lot of development. I’ve driven there (15-20km away from Seruwila) as recent as Aug 2019.
I read the site is flat ground - so usually the heavy trucks make in roads within the site. I’ve not seen helicopters used on sites in SL.