An independent report suggests Newmont Mining Corp. should not cover two existing lakes near the $4.8 billion Conga project in Peru and should increase the amount of water that will be held in artificial reservoirs.

The Conga project, a proposed gold mine would be the biggest investment in the history of Peruvian mining. Newmont Mining has planned to replace a string of alpine lakes with reservoirs, however, this plan fueled protests in the northern Cajamarca region as some townspeople fear the mine would leave local farmers without water supplies.

In a bid to gain confidence from locals, President Ollanta Humala’s government asked three independent European auditors to issue an evaluation of the mine’s environmental impact study, which was approved by the previous government, Reuters reported.

“Alternatives should be evaluated for the relocation of the mine tailings to try to avoid covering the Azul and Chica lakes,” their 260-page report said.

Other recommendations included increasing the capacity of the artificial reservoirs, more secure storage of waste from a water treatment plant, and trying to conserve more soil.

The government will analyze the report before establishing new conditions for the gold and copper project, said Environment Minister Manuel Pulgar. He declined to give a timeline for the process.

Though the report does not give any cost estimates for its recommendations, Pulgar said Newmont would have to increase its investment to meet the new conditions.

Newmont has indicated it is willing to fine-tune its mitigation plan. It has also said the reservoirs as planned would guarantee a year-round water supply for Cajamarca.