A Chrono Miner would drop off Ore to the Ore refinery, which would be further refined, or "purified", when there was an Ore Purifier present within the base. A Chrono Miner can only carry so much ore, and ordinarily, some of it is lost in the refinement process. Although this isn't much, the Ore Purifier can further refine the ore, and extract more than if it is simply put through the refining process at the Ore Refinery. This gives more profit to the Allied commanders to build up their armies and defeat the opposing force.