The deal values Sapa at 27bn krone (US$3.23bn) and is in line with Hydro's strategy of becoming an integrated aluminium company involved in everything from mining to end-user products
China's overcapacity and US protectionism are likely to be prominent steel issues at the G20 summit in Germany.
The steelmaker reverts to an earlier decision to shut down its Cerro de Mercardo iron ore mine after union negotiations aimed at restarting operations fail.
The long-running saga of the bankrupt La Oroya zinc-smelter has no end in sight, as a fourth attempt at an auction drew no bids.
Shipments of iron ore pellets and unalloyed cast iron to the US also performed well in 1H17.