2015-01-13_HYDROLOGY - M2012032 - Laserfiche WebLink

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determined that there was no connection between the shallow and deep samples, it appears that for some parameters the worst case well measurement should in fact be taken from the deep wells to account for the application of the same standards to the shallow and deep wells. Originally the value used as the representative well value was taken as the maximum concentration recorded in the shallow well measurements, as these wells were believed to be the best representative of the worst case scenario for parameters of concern. However, further inspection of the water document and its review revealed that this methodology must be altered if the standards are to be applied to both shallow and deep well measurements. There are seven parameters in which the worst case well measurement can be found from a deep well sample, however only two of these parameters have proposed standards affected by this change. This is because for the other five parameters, their proposed standard is listed as "Report" due to a lack of an In-Stream Water Quality Standard as well as a Colorado Ground Water Agricultural-Use Standard. The two parameters that will have altered proposed standards to account for the worse-case deep well measurement are chloride and sulfate. The standard for chloride should thus be changed to 2 mg/L, and the standard for sulfate should be changed to 119.75 mg/L. Please refer to the attached Microsoft Excel file to view the ground water data supporting these changes. The alterations to the proposed standards allow all standards to apply to both shallow and deep well samples moving forward while assuring compliance with all baseline well samples previously taken. In summary, your review of the water document is greatly appreciated. To ensure the most accurate and fair standards moving forward it is requested that the standard for TDS be set to 400 mg/L according to the guidelines set out in the CDPHE Regulation Number 41. It is also requested that this standard for TDS only apply to the well water samples and not the tailings samples. A standard for the tailings samples is not believed to be applicable due to the nature of the SPLP test, and therefore a "Report" standard is requested for future tailings samples. Lastly, to insure compliance of previous shallow and deep well samples under the proposed standards, chloride and sulfate require standard alterations. It is requested that the standard for chloride be changed to 2 mg/L, and the standard for sulfate be changed to 119.75 mg/L. These changes are requested to account for worse case deep well measurements. On behalf of Fortune Revenue Silver Mines, we hope you will consider this feedback. Please don't hesitate to call if you have any questions. Thank you. Sincerely. , • le-eic.e Greg Lewicki, Project Engineer Greg Lewicki and Associates CC: John E. Trujillo Dianna Stoopnikoff Clint Fletcher References [1] Water Quality Control Comission,"Regulation No.41 The Basic Standards for Ground Water,"Colorado Department of Public Health and Environment, Denver,2013.