(Adds details on FY results in paragraphs 2-6) Aug 24 (Reuters)...

(Adds details on FY results in paragraphs 2-6)

Aug 24 (Reuters) - Diversified miner South32 Ltd (S32) posted a steep decline in annual profit on Thursday, hurt by easing prices for its key commodities aluminum, coal and manganese.

Prices of South32's crucial commodities - aluminium, coal and manganese - all weakened during the year, as concerns over the economic health of top metals consumer China dampened demand.

Underlying earnings for the year ended June 30 came in at $916 million, lower than the $2.60 billion posted last year. That compares with analysts' estimate of $973 million, according to Refinitiv Eikon.

South32's results come at a time when workers at the diversified miner's Appin mine failed to reach an agreement with the company over a wage-related dispute.

In July, South32 had flagged its Hermosa project would recognize a $1.3 billion non-cash impairment expense, as a result of which it reported statutory loss of $173 million, compared with a profit of $2.67 billion a year ago.

The Perth-based miner, which was spun off from mining giant BHP Group (BHP) in 2015, declared a final dividend of 3.2 cents per share, down from 14 cents in the prior year.