2017-08-16_PERMIT FILE - C2010089A (3)

Home Browse Search

Protection of the Hydrologic Balance This section is divided into discussions: one of the "Protection of the Hydrologic Balance" and the other of the "Probable Hydrologic Consequences of Mining". Significant data have been collected over the years at the New Horizon #1 Mine and the adjacent existing New Horizon 2 Mine which allows making better predictions for both topics. A) Protection of the Hydrologic Balance Introduction Surface mining activities to be conducted at the New Horizon North (NHN) mining area outlined in this permit application have been planned to minimize impacts on the hydrologic balance. Mining, reclamation, and monitoring plans and data reporting have been developed to be consistent with the findings of the Probable Hydrologic Consequences analysis presented at the end of this section. The following discussion addresses mining, reclamation, and monitoring plans, and data reporting in the context of how they relate to ground and surface water protection and monitoring. References to those sections which contain details regarding mining and reclamation plans and practices have been also incorporated. Finally, discussions on water rights are also included. Ground Water Protection The discussion for ground water protection has been divided into three parts: 1) ground water quality; 2) ground water quantity; and 3) ground water monitoring: Ground Water Quality Mining practices that involve replacement of spoil material into mine pits are detailed in Section 2.05.4(2)(c), Backfilling and Grading. Topsoil and overburden handling procedures are detailed in Section 2.05.4(2)(d), Topsoil Redistribution. These handling procedures were developed after reviewing the physical and chemical properties of the overburden and coal in the NHN permit area (see Section 2.04.6, Geology). Extensive testing of the spoil (backfill) water quality (pH of about 7.0) at the New Horizon 1 area has shown that areas that have a higher pyritic content in the shale (which can result in oxidation of the pyrite, resulting in a lowering of the pH and an increase in Total Dissolved Solids) have been neutralized by both the neutralization potential of the majority of the backfill and the higher pH of the irrigation water (pH of 8.0 to 8.5). This process will occur over hundreds of years in the backfill until the water quality gradually approaches that of the typical overburden water, which is high in TDS. In the Probable Hydrologic Consequences Item 5),"potential impacts of replaced spoil on groundwater quality", this oxidation and its impacts are discussed in extensive detail. Overall, the impacts to the groundwater quality and the waters downstream are not significant, although they occur for a lengthy period of time. NHN has developed plans for sampling overburden during mining to identify the quantity and quality of deleterious material (see Section 2.05.4(2)(c), Backfilling and Grading). Section 2.05.6(3) Page 1 April 2016 (PR -01)