Jan 20 (Reuters) - Australia's South32 clocked lower second-quarter manganese ore production on Monday, as the shutdown of its Groote Eylandt Mining Co (GEMCO) unit due to a cyclone in March continued to crunch output.

The world's biggest producer of manganese logged 1.1 million wet metric tons (wmt) of the steel additive for the quarter ended Dec. 31, down from 1.3 million wmt from a year earlier.

That compares with a Visible Alpha consensus estimate of about 602,000 wmt.

(Reporting by Adwitiya Srivastava and John Biju in Bengaluru; editing by Diane Craft)

((Adwitiya.Srivastava@thomsonreuters.com;))