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Mr. Vern Pfannenstiel <br />February 11, 2010 <br />10. Comment 10 in our letter of August 28, 2009 noted concern with calculations of <br />geometric means of hydraulic properties that combined data from two different types <br />of tests, constant head tests and slug tests. The Division cannot accept the grouping <br />of constant head and slug test data in the calculation of geometric means for <br />transmissivity and hydraulic conductivity of the Wadge overburden and <br />underburden, given the wide range of results from the small sample size obtained in <br />two types of tests. Please revise the permit application in accordance with either <br />Alternative "A" or "B", below. <br />Alternative A <br />Revise Table 2.04.7-T2 as follows: <br />a) Include only slug test data in the calculation of geometric means for the <br />Wadge overburden and underburden, <br />b) Show constant head data in the table separate from slug test data, <br />c) Identify data by test type (slug or constant head), and <br />d) Delete the overall geometric mean. <br />Remove the wording from the first paragraph on page 2.04-49 that begins with "The <br />grouping of wells...." and ends with "....consequences of the proposed mining," as <br />this wording will be made obsolete by excluding constant head data from the <br />geometric means in Table 2.04.7-T2. <br />Change analyses and references elsewhere in the permit to reflect the different <br />values determined from the slug tests and constant head tests for transmissivity and <br />hydraulic conductivity. These changes will require two analyses in some cases, one <br />using the slug test geometric mean and one using the constant head value. <br />Alternative B <br />Replace the geometric means for the Wadge overburden and underburden in Table <br />2.04.7-T2 with arithmetic means and identify the data by test type, slug or constant <br />head. <br />Remove the wording from the first paragraph on page 2.04-49 that begins with "The <br />grouping of wells...." and ends with "....consequences of the proposed mining," as <br />this wording will be made obsolete by eliminating the geometric means for the <br />Wadge overburden and underburden. <br />Change analyses and references elsewhere in the permit to reflect the new arithmetic <br />means. <br />Page 2 <br />11. Please add to the description of aquifer test methods the following information: <br />identification of the drilling fluid used (for example air, mud, water) for drilling the