Long-term Monitoring and Targeted Assessments to Improve Management of Mine Wastes - the Batu Hijau Project

摘要

The Batu Hijau copper/gold mine/ operated by PT Newmont Nusa Tenggara, is located in the south-western part of Sumbawa Island, Indonesia, and is situated ~10 km from the south coast at an altitude of -450 m above sea level The mine became fully operational by year 2000 and processes approximately 120 000 t of ore per day that contain an average of 0.53 per cent copper and 0.4 per tonne (g/t) gold. Tailings management at the mine includes a. deep-sea tailings placement (DSTP) system, that discharges tailings through a pipeline via an outfall located at a depth of 125 m at the head of the submarine Senimu Canyon (Figure 1),The environmental impact assessment undertaken prior to approval of the DSTP evaluated both on-land tailings storage facility (TSF) and DSTP options for tailings management. Negative attributes of the on-land TSF included removal of approximately 2300 ha of forest/agricultural land, the potential relocation of >2000 people from their communities, the high average annual rainfall (>2500 mm) and. potential for earthquakes presenting challenges for water management and creating a long-term risk of failure. 'The final choice and Indonesian Government's approval of DSTP was also influenced by the close proximity of the deep submarine canyon to the mine. The Batu Hijau mine is one of the larger examples of DSTP in the world and deposits tailings at the greatest depth. The depth of the main canyon increases to >2000 m within 20 km of the coast, and to >3000 m approximately 50 km. from the coast.