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9/5/13 State.co.us Executive Branch Mail - Fvvd: Response to Corley Co MW -NW <br />Binns - DNR, Janet <janet.binns @state.co.us> Wed, Sep 4, 2013 at 11:29 AM <br />To: Alysha Hernandez - DNR <alysha.hernandez @state.co.us >, Mary Rodriguez - DNR <br /><mary.rodriguez @state.co.us> <br />Cc: Daniel Hernandez - DNR <daniel.hernandez @state.co.us> <br />Please scan as: <br />Southfield Mine C1981014 <br />TR40 <br />Dr. Corley's response to EFCI's letter dated 8/27/2013 <br />Thank you <br />Janet H Binns <br />Environmental Protection Specialist III <br />Colorado Division of Reclamation, Mining and Safety <br />1313 Sherman Street, Room 215 <br />Denver, CO 80203 <br />office: 303.866.3567 ext. 8107 <br />email: janet.binns @state.co.us <br />George, <br />I have carefully read your letter attached to the email below. Here is my critique of your responses. <br />In paragraph 3 you make references to water levels in MW -65, SF -87 -07 and SF- 87 -09. When were your observations made <br />for each of the SF series holes or where is the report to be found, who made the water level measurements, how and by <br />whomwas the surface or casing top elevation determined, and how was the static water level determined? The reason that <br />I ask these questions is because of the inconsistent use of various vertical datums between various Southfield maps with <br />the random Southfield vertical datum used for subsidence monitoring and then eitherNGVD29 orNAVD88 on other maps. <br />As you know I have asked what vertical datum has been used on Map 17 and for Kent Crofts vegetation maps, neither of <br />which specify the vertical datum used. Without knowing what benchmark was used it is difficult to know how various <br />maps compare. If your reports of water level elevations in MW -65, SF- 87 -07, and SF -87 -09 were determined from the drill <br />log elevations for thosc drill holes, pleas be advised that there are large errors in thosc surface elevations that cannot be <br />explained by subsidence in the event that your elevations are frompre- mining surveys. I did not include MW -23 for two <br />reasons. First, it is not located on ourproperty, and second, it is located about 700 east and is upgradient of the Southfield <br />workings. As for MW -16, I don't think you can compare water level elevation data from many years ago with the current <br />monitoring and open drill hole information. Your clarification letter is very incomplete without the additional information <br />provided by the Corley Mine Well and the surface discharge in Second Alkali Creek. <br />https: / /mai l.g oog le.conVmai 1 /u /0 / ?ui =2 &i Ire29129fcb5 &�iev�-- pt &search =i nbox&th= 140ea06l931 a2742 1/3 <br />