Any combination of 3 mages/melee level 60-65+ should not have a problem trioing this mission. 75BRD 75WAR 75SAM destroyed the first wave and had to wait for the second set.
It is not necessary for other party members to be on the mission, however they will not receive notes for its completion.
Reports indicate that a large battalion of beastmen raiders has been dispatched to Ruhotz Silver-mines. Travel to the mines via the Rolanberry Fields (S) and aid the legionnaires stationed there in defending the location.