The fact that Governor Fang specially took it out as a congratulatory gift suggests that it is not just any ordinary barren hill, nor is it a small mountain; it is a mine.
This mine is not an iron mine, but a copper mine.
Iron ore can be smelted into pig iron and cast into armor and weapons. The iron pots and shovels used by the common people also come from iron ore.
The importance of a copper mine is no less than that of an iron mine. With a copper mine, it is possible to mint large batches of Copper Coins. Some noble families in the Northern Land have such "industries" in secret. Most of the privately minted coins are slightly lighter than the court-minted Copper Coins, yet they still circulate normally among the populace.
Once such activities are discovered by the court, they are naturally a grave crime punishable by the extermination of the family.
