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Nov 24 (Reuters) - Brazilian iron ore miner Vale SA VALE5.SA says:
* To extend $115 million in credit to joint venture Samarco in first-half 2017
* Samarco partner BHP Billiton (LON:BLT) Ltd BHP.AX to extend short-term lines of credit to joint venture in a similar manner
* Vale estimates will have to pay $181 million in first-half 2017 for Samarco environmental liabilities after tailings dam collapse
* Expected environmental liabilities payouts to be discounted from 3.7 billion reais in provisions set aside by Vale in second quarter of 2016 Further company coverage: VALE5.SA BHP.AX