The King had a small warehouse in Huika where he kept some stones.
The warehouse was small but because the mining activity in the field was very rampant, every inch of land was quite precious and expensive. Most of the residential areas were mines that had been filled and the houses of the miners were also on such filled land.
However, that warehouse was not in another place. It was in an empty space near the border of the residential area. No mining activity took place beneath the ground. Being able to construct a building in such a place showed how capable its owner was.
Li Du knew that it must be part of the Old King's inheritance. Based on the capabilities of the current King of Hpakant, it would be strange if he could even afford a building like that.