China imported a record amount of iron ore in September, according to Standard Bank Group Ltd., and notched a slight rise in October that leaves analysts scrambling to revise their price estimates for the coming year, especially when additional data suggest that Asia’s largest economy is back on track for growth, instead of contraction. In response, countries like Australia — whose iron ore exports are directly tied to Chinese demand — have cranked up their production rates. Production has jumped so much that there could be an iron ore surplus by the second half of next year. That will undoubtedly require another round of price estimate revisions from Australia’s Bureau of Resources and Energy Economics. Until then, though, investors in iron-ore commodities will have a chance to recoup some profits that may have evaded them during the last couple of years.