May 10 (Reuters) - South32 Ltd S32.AX :
* Advises production at Illawarra Metallurgical Coal in FY17 is expected to be at least 10 percent below prior guidance of 7.9Mt
* Revised production forecast for FY17 to be provided, with decrease expected to translate directly to sales given low inventory levels
* "A commensurate increase in unit costs is also anticipated"
* On 7 May 2017, elevated gas concentrations were recorded at Appin Area 7; all personnel were safely evacuated
* Production at Area 7 and Area 9 longwalls has been suspended until our investigation into incident is completed Source text for Eikon: Further company coverage: S32.AX