Laserfiche WebLink
6.4.7 EXHIBIT G — WATER INFORMATION <br />Groundwater <br />The gravel layer to be mined is an alluvial aquifer with an average saturated <br />thickness of 23-25 ft. Groundwater occurs at an average depth of 7-9 ft. below <br />ground surface in the local area. The direction of groundwater flow is generally <br />from the southeast to northwest but can more closely parallel the flow of the river <br />during high-flow periods in the spring and summer. Groundwater discharges to <br />the South Platte River. <br />The proposed mining project will have a constructed slurry wall around the <br />perimeter for the purpose of hydraulically isolating the mine from the local aquifer <br />and therefore protect injury to the river and associated water rights. Initial <br />dewatering of pore water within the slurry wall will occur, which is expected to <br />last several months. All depletions to the river have been accounted for in the <br />Temporary Substitute Water Supply Plan (TSSP), which was filed with the <br />Colorado Office of the State Engineer (OSE) in April of 2008. Initial comments <br />were received by the reviewing consultant for the OSE, but this plan was <br />withdrawn from further consideration in 2009 and will have to be re -submitted. <br />All process water needs for dust control, washing of aggregate, etc. were <br />accounted for in the TSSP. <br />Small amounts of process water required for a wash plant (if one is to be used in <br />this operation) will be obtained from an existing alluvial well located near the <br />southeast corner of Cell 1 (to the exterior of the slurry wall). This well is currently <br />permitted with the OSE. <br />The slurry -wall lined pit will create an impediment of sorts to the current <br />unrestricted flow of groundwater in the immediate area. However, there are no <br />alluvial wells or below -grade structures nearby that would be negatively impacted <br />by groundwater effects caused by the slurry wall. This would mean drying -up of <br />an alluvial well in the groundwater "shadow" of the slurry wall or flooding of <br />basements by "mounding" of groundwater in the up -gradient area of the slurry <br />wall. The Lupton Lakes Pit operated by Martin -Marietta Materials to the east of <br />the proposed Chavers Mining Resource is an extremely large sand and gravel <br />mining operation which currently has approximately 1/3 of it's circumference <br />enclosed by a clay -liner and upon completion will have a complete clay liner <br />placed around the pit and will block groundwater coming onto the Chavers site <br />from the east and somewhat from the southeast. The property to the south is <br />vacant and is owned by the City of Aurora for future expansion of large alluvial <br />wells as part of their Prairie Waters project. If mounding were to occur upgradient <br />from the Chavers slurry wall, Aurora's alluvial well pumping would not be <br />negatively impacted and in fact, would probably enhance their pumping needs. <br />The land to the north and west would not be impacted at all. <br />July 2015 Chavers Mining Resource <br />Regular 112 Permit Application <br />