One of the downsides of AW is you end up being told far more than you ever intended to know when you ask a question.
True, but the other side of that is too little info and acknowledgement, as I did.
For instance, your fuse information is vital, and in this case, I only implied the confined aspect of making gunpowder into an explosive agent.
Provided a sufficient amount of gunpowder is available, an eight-pound keg of black powder poured into a small hole of firm soil, properly fused, and mud-capped might produce a sizable "WUMP!"
Off topic: A neighbor farmer I once helped blow out dead cottonwoods when I was a teen put two 40% sticks under roots. The dynamite blast left the tree standing, merely exposing roots like spider legs. Next, he doubled the charge, told me to shovel in mud from the creek, and went to lunch. My mud-cap was a work of art, thickly covering all roots and bottom of the tree. When he touched it off, the tree launched like a Minuteman missle, going at least a dozen feet in the air, before turning on its side and thundering to earth. The blast rattled every window in his house 200 yards away and cracked two. I was thrilled and couldn't wait to launch another tree!