2018-03-09_ENFORCEMENT - M2004031

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' EXHIBIT 22 ' surface elevation at the well, the Permanent Drain invert elevation (5036.5 feet above mean sea level) and the beginning and end of slurry wall construction (May-August 2005). Water levels in Well HZMW-2, located on the west side of the Orr property, clearly show the impact of the slurry wall and the relocation of the Bull Seep on the hydrologic regime. A sharp water level rise occurred just after slurry wall construction began. Water level data prior to slurry wall construction indicates seasonal variation most ' likely due to relocation of the Bull Seep and periodic releases of water in the Bull Seep. Wells HZMW-11A and HZMW-11 B are about 10 feet apart and located adjacent to the north property line of the Orr property. ' Similar variations and cause and effect are indicated in water levels in Wells HZMW-11A and HZMW-11 B. However, water levels in Well HZMW-11 B returned to pre-slurry wall conditions after November 2005. It is important to note that Well HZMW-11A is screened from 5 to 10 feet below the land surface and Well ' HZMW-11 B is screened just above the bedrock from 27 to 37 feet. These wells are completed in this fashion to evaluate shallow groundwater conditions in the jurisdictional wetlands that are present in the area of the wells. Well HZMW-11A is highly influenced by water in the Bull Seep and other sources of ' water such as the drains under the Fulton Ditch. The return to pre-slurry wall groundwater conditions in Well HZMW-11 B demonstrates that the Bull Seep and Fulton Ditch underdrains have little long-term impact on the deeper groundwater flow regime but have a material impact on the shallow groundwater ' regime. The presence of shallow groundwater prior to the construction of the slurry wall is demonstrated by the shallow water levels in Well HZMW-11A and the mapped occurrence of jurisdictional wetlands on the mine property and inferred wetlands on the Orr property. Surface Water and Jurisdictional Wetlands The Bull Seep and the Fulton Ditch are major surface water features that impact the hydrologic regime at ' the Orr property. The Bull Seep is by far the largest contributors of water to the surface and groundwater regimes. The Fulton Ditch is lined with concrete. Underdrains that discharge adjacent to the Orr property have been installed to control uplift pressures in the ditch when the ditch is not conveying water. These drains also contribute water to the Orr property. The water from the Bull Seep and the Fulton Ditch and upland groundwater have created jurisdiction wetlands on and adjacent to the Orr property. Because these wetlands are jurisdictional they must be maintained. Al has entered into an agreement with the US Corp of Engineers to replace and maintain the wetlands on the Al property. Any plan to maintain the pre- mining hydrologic regime must protect these wetlands. The Permanent Drain invert elevation (5036.5) is shown on the hydrographs. The water level data shows that a drain at this elevation will lower the groundwater level near Well 2 by approximately two to two and one-half feet (see Figure 4) and approximately two and one-half to three feet in the area of Well 11A. An inspection performed by the DRMS on August 19, 2015 indicated that the temporary drain which is completed at higher elevation (5038.8) than the proposed Revised Permanent Drain has begun to lower ' the groundwater in the area of the Orr property. "Based on observations made during the inspection it appears that the temporary plan has begun to mitigate the impacts of the groundwater mounding. The Division believes that it will take several months to completely evaluate the effects of the temporary plan. The Division will continue to work closely with the Operator and the adjacent landowner." 3 Tetra Tech