6) “Wetland degradation”

“Wetlands within the project area are severely degraded in many areas due to past overgrazing by livestock, and in some cases due to naturally occurring poor quality water (e.g., low pH and elevated iron). Baseline studies rated many of the wetlands as “poor” to “very poor” in terms of habitat biodiversity and ecosystem quality”.

It is unclear how much of the degradation of wetlands is from livestock vs. Yanacocha mining. This highlights the importance of using an appropriate pre-mining baseline for wetlands/biodiversity in comparable socio-ecological systems without mining. Low pH could be natural if soils are acidic, but could also be attributable to acidic tailings/runoff from Yanacocha mining site. By using GIS to model hydrology and map wetlands and farming activities, this can be interrogated. On a more subtle note, the language chosen by the EIA has the appearance of being biased in favor of mining interests, and reluctant to link existing or projected mining to adverse impacts.

7) “Lack of groundwater aquifers”

“No useable groundwater aquifers exist within the strata to be mined”.

Once again this seems biased and misleading from a systems view. Aquifers do not have to be located in mined strata to be impacted by mining up-gradient. Robust hydrogeological modeling would reveal flow fields and impact areas within hydrological basins and sub-basins.

8) “Groundwater contribution to stream flow”

“Groundwater accounts for approximately 3% of base flow in receiving streams. This groundwater contribution represents the low flow conditions in the streams during the dry season”.

It is not unusual for groundwater to contribute a few % to wet season flows, especially in humid tropics – then 100% during dry season.

9) “Natural lake contribution to surface water flows”

“Natural lakes contribute minimally to surface water flows in the vicinity of the project area, especially

during the dry season. The water balance calculations assume a conservative 3% loss to groundwater, which during the dry season would report as surface water. As an example, for Perol Lake this would be equivalent to less than 3% of the current dry season flow rate”.

This may be so: in the comparison between contributions to stream flows from runoff vs. lake outflow, it’s not unusual in the tropics for runoff to dominate strongly. However, lakes are important storage reservoirs in hydrological basins, and they help to stabilize stream flows and trap suspended sediments. The more pressing question this finding may obscure is that runoff from mining lands will have major impacts on the quantity and quality of down-gradient stream flows and lake quality.

10) “EIA recommendations to base flow”

“Base flow replacements committed to in the EIA will equal or exceed current flow conditions during the dry season”.

See above. This mitigation may obscure the more significant impacts from very large-scale contaminated runoff.