Antam’s main gold and silver production is sourced from its gold mine at Pongkor, West Java, Indonesia’s only underground gold mine. Located at Mount Halimun National Park, about 90km from Jakarta, it covers a surface area of approximately 4,058 ha.  Indications of gold deposits at Pongkor were discovered by Antam’s Geology Unit in 1981, and production commenced in May 1994 after Antam secured the mining license in 1992.

The Pongkor mine has three primary veins of gold, all of which were mined in 2003: Ciguha, Kubang Cicau and Ciurug. A conventional cut and fill stoping mining method with hydraulic replacement of tailings is used for the first two of these veins with hydraulic placement of tailings as fill. A mechanised cut and fill method, with hydraulic jumbo drill and load haul dump (LHD), was introduced in 2000 for the third vein, Ciurug. The use of mechanised cut and fill is intended not only to assist in meeting the increased production targets but also to lower overall production costs and to improve efficiency.

Pongkor Gold Mine and its facilities

Ball mill in operation at Pongkor gold mine

The processing plant at Pongkor mine was originally designed with a capacity of 182,500 wmt per annum of ore, at grades of 15g/t for gold and 156g/t for silver, with recoveries of 96 per cent. and 79.5 per cent. for gold and silver, respectively.

The ore then went through various process at Pongkor’s facility which include crushing, milling, cyanidation, carbon leaching and stripping, electro winning to melting and casting to produce bullion/ dore.

The waste is processed at Antam’s detoxification plant, consisting of two tanks, to reduce the cyanide content of tailings to below the threshold limit value of 0.5 ppm, so that it can be safely used as a total tailing backfill system in combination with cement.

The dore/bullion is then sent by armored vehicle to Indonesia’s only precious metals refinery, Logam Mulia, located in Jakarta.

Please refer to the section Precious Metal Refining for further information on Antam’s precious metal refining operation.

VIDEO OVERVIEW:
Please view this video have a glimpse on how gold and siver are mined and processed.