Have ya ever heard of a yarder? they use  em for mining or logging will make short order of this matter . you'll have to remove your slalom course,It has a dragline bucket on it with two dozers one on each side one has pulley on it the other has spool a cable runs between with bucket attached.Let out slack bucket drags bottom pull material to ya spool side then tighten cable and send back to pulley side dig to grade and slowly move dozers down the berm.probably take couple weeks. you'll also need a support loader to haul off all the material.sounds like you guys got some serious cutting to do three to four feet.Going to cost some dough sounds like your lucky no one hasn't gone out front a broke a neck.Or you can use the vacuum cleaner idea.