John Henry No.1 Mine 2014
Cumulative Hydrologic Impact Assessment (CHIA)
As the regulatory authority for Peabody Western Coal Company (PWCC) surface coal mining and reclamation operations at the Kayenta Complex, the Office of Surface Mining Reclamation and Enforcement (OSMRE) is required by regulation 30 CFR 780.21(g) to complete a cumulative hydrologic impact assessment (CHIA). The CHIA assesses whether the mining operation has been designed to prevent material damage to the hydrologic balance outside the permit area. The CHIA is not updated at a specified interval. 30 CFR 780.21(g)(2) states "an application for permit revision shall be reviewed by the regulatory authority to determine whether a new or updated CHIA shall be required." A revision to PWCC's permit application package was submitted to OSMRE in September, 2010, and OSMRE subsequently determined the CHIA should be updated. This most current update to the CHIA (2011) replaces the 2008 updated CHIA and the original CHIA written in 1989.