SYDNEY, July 22 (Reuters) - Australia's South32 said on Wednesday it missed June quarter nickel production guidance due to labour unrest at its Cerro Matoso mine in Colombia and a drop in ore grades.
Output of the metal was 40,000 tonnes against guidance of 43,000 tonnes provided in April and down 9 percent year-on-year, the company said in its quarterly operations report.
Production is expected to decline by a similar amount in the 2016 financial year before stabilising the following year, the company said.
South32 inherited the mine from BHP Billiton in a demerger into a separate company finalised in May.
Miners ended a 17-day strike at the Cerro Matoso mine in May after reaching agreement on a dispute that led to a declaration of force majeure.
An 11 percent reduction in the grade of ore that was mined contributed to the shortfall, according to the company.
Commodities analysts said the decline would have little impact on the global nickel market, where a supply glut has helped drive prices to the lowest in six years.
Exchange stockpiles of the metal used to make stainless steel nearly doubled in the 18 months to June.
The three-month London Metal Exchange futures price stood at $11,630 a tonne at 0242 GMT.
South32 also said it would take a $1.9 billion fiscal 2015 impairment on its manganese and coal businesses.
Reporting by James Regan; Editing by Ed Davies