SUMITOMO MINING <SMIT.T> RAISES NICKEL OUTPUT Sumitomo Metal Mining Co said it will raise its monthly nickel output to around 1,750 tonnes from April 1 from 1,650 now because of increased domestic demand, mainly from stainless steel makers. Sumitomo produced 1,800 tonnes of a nickel a month until end-1986, but cut output in January because of stagnant demand, a company official said. Calendar 1987 production is likely to fall to around 20,000 tonnes from 22,000 in 1986 as a result of the first quarter reduction, he said. Sumitomo is Japan's only nickel producer.