This is what we used for heating in the winter over 2013/2014. It is a dump truck load of firewood, approximately 2 cords.
It took about 5-6 person hours to stack inside shelter and this went over two days.

This year we are trying out something drier and packaged better and hopefully better overall:

wood pellets.

This pile took only 2 person hours to stack and was much better on the back and arms. Stacking was also much easier as one did not have to arrange the split wood into specific places and orientations to form a stable pile. Even then the pile was not so stable.

We think this will provide the same amount or more heat than did the pile of firewood this winter.
Oh yes… you are looking at 3 tons. 150 bags of 40 lbs each (or 18kg).
50 bags@40lb=2000lbs=1 ton, 50 bags@18kg=900kg=1 tonne. give or take.