Optimum would be a Char that is already able to fly Expedition Frigates at least he should be able to fly Barges or Exhumers.
Skills like the 14 must have ones for flying all the Sub-Capitals are a must have
Mining 5, Astrology 5, Mining Upgrades at least 4, Mining Drones and relevant Drone skills at least 4, Strip Miner at least 4
Ice Mining at least 4
No Kill rights
No bad history
Transfer fee should be on seller
Price should be between 3-5B