TEMPO.CO, Jakarta - Freeport Indonesia has started producing copper from its Grasberg block cave underground mine in 2019. The US-based mining company has set a target to produce 240,000 tons of copper ores each day, increasing from last year’s 140,000 tons per day.

However, the increased productivity is expected to raise mining waste or tailings. According to Budi Santoso, the director of the Center for Indonesia Resources Strategic Studies, such waste is a consequence that cannot be avoided.

“An increase in production will eventually lead to the rising volume of waste,” said Budi on Tuesday, May 8.

Read: Freeport to Close Grasberg Mine Operation

Furthermore, Budi said that the copper content that will be mined in this location is only 2 or 3 percent per ton. Based on that initial calculation, Freeport’s underground mine production will reach 233,000 tons per day. The mine currently produces 240,000 tons of waste each day.

Budi urged Freeport to renew its environmental permit to improve its waste management. The company’s mine tailings are currently being flowed from the Aghawagon River to the Otomona River, which reaches its final destination at the Ajkwa Deposition Area. Budi claims that the river can no longer accommodate the ever increasing waste volume.

Freeport has actually proposed changes in its waste management in the 2015 environmental evaluation document. A year later, the company applies for a revision to the environmental impact assessment.

Read: Govt Set to Sue Freeport Indonesia for Environmental Woes

However, before the permit was officially granted, Freeport expanded its deposition area from 230 square meters to 450 square meters in 2015. This move that was considered illegal was questioned during the Supreme Audit Agency (BPK) examination last year, as BPK auditors saw that Freeport’s mine tailings had overflowed to land areas, river, up to the ocean. The BPK concluded that it is caused by an improper pool shelter.

However, Freeport McMoran CEO said that the company was forced to expand its pool shelter since the permit issuance was sluggish.

ROBBY IRFANI