SWCA Environmental Consultants

The purpose of this memorandum is to detail the steps taken between the DEIS and final EIS (FEIS) to further revaluate potential mitigations for the project, leading to the mitigation and monitoring measures included in the revised appendix J of the FEIS.

The purpose of this process memorandum is to detail the process used to evaluate these comments, the decisions made by the Tonto National Forest with respect to addressing the comments, and the rationale for those decisions.

At the public hearings held during the comment period for the DEIS, commenters expressed concern over potential schedule delays and technical complications with the block cave mining technique proposed for use in the underground operation at the Oyu Tolgoi mine.

Comments received on the DEIS, including those from the U.S. Environmental Protection Agency, questioned the appropriateness of stopping the analysis at these locations and not assessing impacts further downstream, particularly to community water supplies. In response, Section 3.7.2 of the FEIS has been modified to discuss further downstream impacts.