Laserfiche WebLink
EXHIBIT G WATER INFORMATION <br /> The North Hangs Mine affected area is located adjacent to the Colorado River. Mining will not <br /> mine closer than 100-ft of the Colorado River. The entire site is within the Federal Emergency <br /> Management Administration (FEMA) Floodplain Zone A (100-YR event). No floodway is <br /> mapped in this area, according to FEMA. Groundwater is roughly four feet below the natural <br /> grade and is the alluvial aquifer of the Colorado River. <br /> This exhibit addresses Rule 3.1.6(1) and demonstrates how the mining and reclamation plans <br /> will minimize any disturbance to the prevailing hydrologic balance of the affected land and <br /> surrounding lands. <br /> 1 . Water Quality Protection <br /> The main concerns regarding water quality are potential impacts to surface or groundwaters <br /> from sediment, hydraulic fluids, or diesel fuel. Sediment will be controlled through the use of <br /> stormwater retention within the disturbance area throughout the life of the mine. All stormwater <br /> runoff and surface water flows from the local drainage area will be collected with control <br /> measures built around the site. This includes mine slopes and the stormwater berms. This will <br /> contain all sediment within the site and prevent its unattended discharge from the site. Hydraulic <br /> fluids and diesel fuels will be contained within any vehicles through the use of best practices of <br /> maintenance and regular inspections of vehicles, hydraulic lines, and any other potential <br /> sources of spills. Diesel is proposed to be stored on-site in double walled tanks, the additional <br /> wall acting as the required secondary containment. Furthermore, the tanks will be located away <br /> from exposed ground water. Inadvertent spills that occur during fueling or refilling operations will <br /> be cleaned up immediately utilizing spill kits located adjacent to all fueling areas. The fuel farm <br /> location can be seen on Exhibit C maps. <br /> During mining, dewatering will take place within the pit. This will be accomplished using a pit <br /> pump installed below the pit floor. This pit pump will be surrounded by a gravel filter berm. Mine <br /> process and stormwater will discharge via the dewatering system under an approved Colorado <br /> Department of Public Health and Environment discharge permit. <br /> 2. Floodplain <br /> The 100-year floodplain is shown on Exhibit C and F maps. The entire disturbance area is within <br /> the floodplain. Temporary stormwater control berms, topsoil, and overburden stockpiles will <br /> exist during mining, but will be removed for reclamation. Additionally, the removal of material <br /> from the site will create storage space below the existing grade and above the groundwater <br /> table, potentially reducing the downstream negative impacts of floods. <br /> In the event of flooding of the site, the pit pump will be disabled, and equipment removed from <br /> the pit floor. The pit will then be allowed to fill with water. Pumping will only resume once the <br /> North Hangs <br /> December 2024 G Lewicki& Associates <br />