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Introduction <br /> The following report presents the results of a hydrogeologic evaluation regarding a proposed dry <br /> mine gravel quarry operation to be operated by Asphalt Specialties Company, Inc., (ASCI) near <br /> Evans,Colorado.ASCI identifies the proposed mine as Evans Mining Resource. <br /> This evaluation consisted of reviewing available hydrogeologic data and inputting those data into a <br /> numerical groundwater flow model. The model was then used to estimate the effects of <br /> dewatering operations on the surrounding groundwater hydrology. This report was prepared as <br /> part of an OMLR 112 permit application.The site location is depicted on Figure 1. <br /> Background Information <br /> The proposed gravel quarry is located in the E1/2, E1/2,SE1/4 of section 35 and a portion of the <br /> SW1/4 of section 36, Township 5 North, Range 66 West of the 6th Principal Meridian. The <br /> property address is identified as 17085 CR 394, Evans, CO. The surrounding land use consists of <br /> agricultural, rural residential and oil and gas gathering. The proposed disturbed mine area <br /> occupies an estimated 149.1 acres. The anticipated extraction depth will vary between 37 and <br /> 45 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 June 2020, 16 soil <br /> borings were drilled from ground surface to bedrock to determine the potential aggregate mass <br /> within the proposed mine boundary. In addition, seven groundwater monitoring wells were <br /> installed in March 2022.Soil boring and well logs are provided as Appendix A. <br /> Bedrock elevations were obtained from mine geotechnical studies, and well records from the <br /> State of Colorado Division of Water Resources (Division). The depth to bedrock within the <br /> proposed mine pit boundaries varied between 35 and 45 feet below ground surface. In general <br /> soil conditions consist of two to four feet of top soil and sandy clay underlain by 30 to 40 feet of <br /> sand and gravel. The coarse alluvial deposits are underlain by bedrock which consists of <br /> siltstone,sandstone and claystone. <br />