Iron smelter not working

[Smurdley]

have 2-level 2 iron smelters. One consistently indicates that it is short of iron ore, yet the storehouse shows an ample amount. I tried "buffing" it, to no avail. Only one square separates the two.

Why does one produce constantly and the other not? Do I have to move the non-working one? I hope not as it would be a BIG loss in hardwood and marble.

[Mistapink]

Did the iron smelter work prior to upgrading the building?

[Smurdley]

I found out that the smelter requires 8 ore and since one is closer to the storehouse, it always gets the first 8 ore that is ready. Once I "buffed" the Iron mines, the other smelter started up again.