The ore silo was a cylindrical open-topped structure that was designed to keep superheated excess raw ore for later processing and manufacturing of units. The ore was collected via pipes to the nearest ore refinery, where the raw material was processed, as well as war factory structures, where the smelted ore was utilized.
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This Silo can hold up to 1,500 credits of smelted ore. Guard it carefully. If destroyed or stolen, the amount stored is deducted from your account. - Command & Conquer: Red Alert manual