The cheapest and easiest way to do a mine effect is as follows:
Take a small board
Make a fulcrum with a rock
Place the board on it
Hide it in some grass or something.
Cover one end of the board with a lot of dirt.
When a guy is running a way and hits a "mine", have him jump on the end not covered in dirt and then jump again to go flying. Dirt flies. He flies. Everyone's happy with no explosions required.
Add an explosion sound in post
The animation at the top of the page is courtesy www.killeranimation.com
