Worldguard selection rollback on a timer.

ie. Select area, tell hawkeye to roll it back every x period of time. Voila, instant replenishable mines. Would replace a few plugins.
Probably would have to check to make sure players were in a safe spot, or place them in a safe spot. Possibly with a console warning before the event occurs.

MonsterTKE

This would be the job of a separate plugin really. The API is available in HawkEye for this to happen, someone just needs to code it :p I would but I don't have time at the moment.