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Y . <br />.MINE ID # OR PROSPECTIN6:ID # M-83-096`" <br />INSPECTION DATE OS~(00 - <br />OSSSRVATIONS <br /> <br />i <br />1 <br />i <br />7 <br /> <br />INSPECTOR'S INITIALS ESC <br />This was an inspection of the La Poudre Sand and Gravel Site conducted by Erica Crosby of the <br />Colorado Division of Minerals and Geology. The operator of the site is Hall-Irwin <br />Construction Company, and no representative was present during the inspection. The Division <br />conducted the inspection in response to issues surrounding the Permit Amendment Application <br />(AM-001) submitted by the operator and concerns expressed by the adjacent landowner regarding <br />the function of the culvert under the Hall-Irwin yard area to adequately drain surface water <br />runoff. <br />On January 21, 2000 Hall-Irwin submitted an amendment to the La Poudre Sand and Gravel Mine <br />Permit No. M-83-090 to change>_ a portion of the post mining land used to developed water <br />resources." A slurry wall had been constructed around Pits #3 and #4 in September 1997 to <br />provide a low permeability liner for a below grade water storage reservoir. The adjacent <br />landowner, Clem McNaney, Eiled two objection letters during the public comment period. The <br />letters expressed concern with the construction of the slurry wall and the possible impacts <br />to the McNaney property from the elevation of the groundwater table and the risk of flooding <br />due to the construction of berms along Weld County Road 13. The Division inspected these two <br />issues on March 10, 2000 with Clem McNaney and Dana Moore of Tuttle Applegate. In addition, <br />the applicant provided additional information regarding the possible impacts to the McNaney <br />property as a result of installation of the slurry wall. A dissuasion of these issues can be <br />found in the Division's docurtient titled, "Rationale for Recommendation for Aooroval. Over <br />Objections-." <br />The Division conducted a second inspection of the site on May 10, 2000 due to Clem McNaney's <br />concerns regarding the culvert installed adjacent to the southeast corner of the McNaney <br />~ property that runs under Che Hall Irwin office and yard area into the "fish pond." The <br />" issue surrounding the function o£ ,the culvert was not included in any of the Letters <br />i. submitted by Clem McNaney to the Division, nor do they appear to be related to the permit <br />amendment addressing installation of the slurry wail. Clem McNaney expressed the concern <br />of the function of the culvert over the phone. The Division believes this issue should be <br />' addressed as a performance standard of the existing permit and handled through the inspection <br />process. <br />The operator installed the cu:Lvert in order to facilitate surface water drainage due to the <br />construction of the cement plaint in the historic drainage area. The location of the cement <br />- plant was approved by the Division in a technical revision to the permit and in a Special Use <br />v Permit from the City of Windsor. The applicant redirected the historic surface water <br />drainage to the south and through a 275-foot long, 12" diameter culvert. The operator <br />measured the fall of the culvert to be 14 inches from the McNaney end to the fish Pond End. <br />while the grade of the culvert is very slight, the operator provided information on the <br />natural Swale that existed prior to mining. The Swale goes from the McKaney property, at an <br />elevation x283 feet, east to elevation 4080 feet within about loo feet, but then remains flat <br />for more than the next 600 feet to the east. This is consistent with measurements taken in <br />the field by the Division. The McNaney house is approximately 3 feet higher than the <br />elevation of the Swale before it enters the culvert. At that point, the culvert grade is <br />approximately a 0.5t slope. A portion of the inlet ditch contains some sediment that may <br />. restrict surface water from entering the culvert. The operator will need to clean the ditch <br />to ensure positive drainage. See page 4 for compliance due dates. <br />On the outlet or "Fish Pond° side of the culvert, contains a standing pool of water. In <br />addition, the culvert was half-plugged with sediment. The ditch leading to the fish }pond <br />also contained some standing water. A slight grade was noted from t4~e outlet of the culvert <br />to the fish pom3. The opeta+:or wilt need to titan out the culvert and ensure the ditch <br />i <br />1 <br />1 <br /> <br />:i <br />~~ <br />