Fifty years go I was working with a road construction crew. At the gravel pit I noticed empty sacks of ammonium nitrate fertilizer and asked about it.
They told me they would drill the holes deep, place one stick of dynamite in the bottom, then fill the hole with the fertilizer.
That was the first time I learned about the explosive properties of fertilizer.
We used an igniter at the bottom of the hole. The igniter was about the size of a hockey puck with a blasting cap wired into it.
Drop a rock in the hole to check for water. If none, then fill with ANFO to about 2 feet from the top. Fill remaining column with drill cuttings.
Wire everything to the blasting machine, blow the horn, then duck !