Australia-based Newcrest Mining has halted operations at Gosowong’s Kencana underground mine on Halmahera Island in Indonesia after the site’s underground section was damaged by a rock fall, leaving one worker trapped.

The company said a geotechnical event that occurred at the mine caused damage to a number of mining levels.

Newcrest Mining said in a statement: "The Kencana mine was evacuated immediately after the event and all personnel have been accounted for, except for one employee who is believed to be trapped approximately 300m underground.

"Our priority is to contact and rescue the trapped employee."

"At this time, our priority is to contact and rescue the trapped employee and provide all support necessary to the employee’s family and the Gosowong workforce."

The company was unclear whether the incident was caused by seismic activity or due to any fault in Kencana mine.

The Kencana project is the third development at Gosowong obtained development approval with first mining in March 2006.

Gosowong is owned and operated by PT Nusa Halmahera Minerals, which is 75% owned by Newcrest.

The operation is located on Halmahera Island, in the North Maluku Province of the Republic of Indonesia and produces gold and silver doré.

Gosowong houses a processing plant which has a capacity of up to 800,000t per year and consists of a primary jaw crusher, a SAG and ball mill circuit, and Vertimill circuit.