BEIJING/MANILA, Nov 3 (Reuters) - Chinese coking coal futures rose for the first time in six trading sessions on Wednesday, surging more than 12% in early trade on big backwardation amid tight supplies, while coke prices also jumped. "Steel production costs are very high now. Mills and coking plants are gaming how much room is there left for further adjustment between spot and futures prices," said Wang Yingwu, analyst with Huatai Futures in Beijing, adding that profits at coking plants are also thin now. Current coke prices are around 1,100 yuan ($171.90) per tonne higher than the January futures contract, while spot coking coal prices are also several hundreds yuan higher, according to a Huatai Futures note. The most actively traded coking coal futures on the Dalian Commodity Exchange soared as much as 12.6% to 2,474 yuan ($386.63) per tonne. They were up 11.3% to 2,446 yuan as of 0330 GMT. Coke futures on the Dalian bourse rose 7.3% to 3,195 yuan a tone, after gaining as much as 8.9% earlier during the session. Benchmark iron ore futures on the Dalian exchange dipped 0.4% to 590 yuan a tonne. Spot 62% iron ore for delivery to China declined $5 to $102 per tonne on Tuesday, data from SteelHome consultancy showed. Steel prices on the Shanghai Futures Exchange were mixed. Construction rebar slipped 0.2% to 4,380 yuan a tonne while hot rolled coils used in the manufacturing sector rose 1.0% to 4,752 yuan per tonne. Shanghai stainless steel futures , for December delivery, faltered 1.4% to 18,470 yuan a tonne. ($1 = 6.3989 Chinese yuan) Reporting by Min Zhang and Enrico Dela Cruz; Editing by Rashmi Aich Our Standards: The Thomson Reuters Trust Principles.