Two independent studies have already been completed on the water component of US-based Newmont Mining's (NYSE: NEM) Minas Conga gold-copper project in Peru's Cajamarca region, paper La República reported.
The first study was carried out by US geochemist and hydrologist Robert Moran, who was hired by US human rights organizations, and is currently being translated into Spanish, according to the report.
The other study was done in November by Spanish hydro-geologist Javier Lambán in collaboration with the NGO Engineers Without Borders from Barcelona.
"The biggest problem is in the treatment of groundwater. The mining project's EIS [environmental impact study] does not provide a complete inventory of water points, so it is important to assess potential impacts on groundwater," Laura González, a representative from the NGO, was quoted as saying.
On the other hand, Lambán believes that Conga's hydro-geological study lacks structure, development and appropriate content, according to the report.
"There are conceptual mistakes such as talking about potential evaporation and not potential evapotranspiration," Lambán was quoted as saying.
The reports will be presented to authorities and be available to the general public.
Meanwhile, in mid-February the government awarded contracts to three other international experts to review the water component of Conga's EIS. These experts were scheduled to meet with Cajamarca authorities on Thursday to receive a report on water resources in the region before starting their 40-day analysis.
With an estimated capex of US$4.8bn, Conga is the biggest investment project in Peru's US$52.2bn mining portfolio.
Newmont suspended construction at the project last November due to increasingly violent protests against the project. Opposition has mainly centered on water use.
Newmont has 51.35% stake in the project, while local miner Buenaventura (NYSE: BVN) and the World Bank's International Finance Corporation hold 43.65% and 5% stakes, respectively.
Average output over the first five years is estimated at 650,000-750,000oz/y gold and 160M-210Mlb/y (72,575-95,254t) copper at cash costs of US$300-400/oz and US$0.95-1.25/lb, respectively.