Diggers

 are a Metalworking, Foraging civilian unit.

Resources Produced

 * +3 Iron from Iron Deposit
 * +3 Stone from Stone Deposit
 * +3 Salt from Salt Deposit
 * +3 Coal from Coal Deposit
 * +2 Coal from Peat Deposit
 * +4 Treasure from Gold Deposit
 * +9 Treasure from Gem Deposit

Upgrades

 * 5 Tools for +1 Iron, Stone, Salt, Coal or +4 Treasure per turn
 * 5 Boards for +1 Iron, Stone, Salt, Coal or +4 Treasure per turn