The white bags are filled with pelletized gun powder. Not the old black powder but very explosive stuff. The powder charges can not be re-used and must be discarded. There are excess powder charges because you don't shoot every round with a full powder charge.
The powder pellets were poured out along a strip of road where nothing else could catch on fire.
This is a very long strip of excess powder about to be burned. It will not explode when lit by hand, it will explode when hit with an explosive charge, so it was not good to have around when we had mortar attacks where it could be accidently hit and exploded.
That's Lt. What'sHisName and me lighting the powder with cigarettes.
The powder begins to burn. The fire moves along the road getting bigger and bigger.
Here the fire has reached its highest point during the burn.