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AWES, LLC <br /> GROUNDWATER MONITORING WORK PLAN <br /> RAPTOR TWO RIVERS MINE PROJECT <br /> WELD COUNTY, COLORADO <br /> 1.0 INTRODUCTION <br /> This Groundwater Monitoring Plan (Plan) has been prepared by AWES, LLC on behalf of Raptor Materials, LLC <br /> (Raptor) for the proposed Two Rivers mine project located in Weld County, Colorado (Figure 1). The current <br /> mining plan includes dry mine gravel extraction from two pits that will encompass approximately 270 acres. <br /> This plan will be submitted to the Division of Reclamation, Mining and Safety (Division) as part of Raptor's <br /> mine permit application. <br /> 1.1 Objectives <br /> The objectives of this Plan are to identify potential liabilities with the extraction of aggregate under semi- <br /> saturated conditions.Specific objectives for the Raptor project are described below. <br /> • To determine the aerial extent of drawdown associated with mine dewatering; <br /> • To determine the effects of dry mine aggregate extraction on local hydrology and water quality; <br /> • To generate predictive models on possible adverse drawdown in adjacent domestic wells;and <br /> • To determine the effects of lined pit reclamation on the local groundwater flow regime. <br /> 1.2 Background Information <br /> The proposed gravel quarry is located in sections 3 and 4 of Township 4 North, Range 66 West and <br /> sections 33 and 34,Township 5 North, Range 66 West of the 6t"Principal Meridian.The surrounding land <br /> use consists of agricultural, rural residential and oil and gas gathering. The proposed mine area occupies <br /> an estimated 380 acres with an extraction area of 270 acres. The anticipated extraction depth will vary <br /> between 12 and 44 feet below grade. <br /> Information provided by geotechnical investigations, monitoring well water level data and water <br /> resource evaluation reports document the local and regional hydrogeology. In January 2015, 12 soil <br /> borings were drilled from ground surface to bedrock to determine the potential aggregate mass within <br /> the proposed mine boundary. These borings were completed as one-inch groundwater monitoring wells <br /> and the well locations are depicted on Figure 2. The depth to bedrock within the proposed mine pit <br /> boundaries varied between 12 and 44 feet below ground surface. In general soil conditions consist of <br /> less than one to six feet of top soil and sandy clay underlain by sand and gravel with occasional clay and <br /> poorly graded sand lenses. The coarse alluvial deposits are underlain by bedrock which consists of <br /> siltstone, sandstone and claystone. <br /> 2.0 GROUNDWATER-MONITORING <br /> 2.1 Monitoring Well Installation <br /> As mentioned in January 2015,WesTest, LLC drilled 12 soil borings from ground surface to bedrock using <br /> hollow stem auger techniques and completed the borings as one-inch groundwater monitoring wells.The <br /> 1 <br />