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Mr. Ross Gubka, P.E. <br />Western Fuels-Colorado <br />December 11, 2007 <br />Page 3 <br />"Cropland-Irrigated Grass with Alfalfa Type (ICG)" beginning on amended page <br />(e)-21. A number of the changes we are requesting with respect to success testing <br />procedures for the ICG type are due to the fact that ICG success testing is based <br />on comparison of reclaimed area production to a technical standard rather than a <br />reference area. Given this fact, discussion of reference area sample size and <br />inclusion of two-sample testing procedures is not appropriate. Please consider <br />the following recommendations, and provide appropriate amendments. <br />a) On page (e)-24, the second paragraph should be amended to clarify that <br />equality is defined as "90% of the approved standard". We would recommend the <br />first two sentences of the paragraph be reworded as follows: <br />For either method, revegetation will be deemed adequate if <br />herbaceous production in the reclaimed block is equal to or <br />greater than (90% oo the standard of 1.84 tons per acre in at least <br />2 of the last 4 years of the liability period, in conformance with <br />DAMS Regulation 4.15.9. If the total harvest measurement method <br />is used, statistical comparison is not appropriate, the reclaimed <br />block production as measured by the total harvest method must <br />equal or exceed 90% of the standard, with no statistical confidence <br />interval. <br />b) On page (e)-25, the first sentence of each paragraph should be amended for <br />clarity. Paragraph 1, Sentence 1, should state: During field sampling for <br />production, at least 15 sample observations will be made within each bond <br />release block Paragraph 2, Sentence 1, should state: Reclaimed area production <br />will be compared to an approved technical standard, as described below. <br />Paragraph 3, Sentence 1, should state: 1) ifsample adequacy exists at the <br />reclaimed site, and the production sample mean is equal to or greater than Q, no <br />statistical comparison is necessary and production at the reclaimed site will be <br />deemed successful. Paragraph 4, Sentence 1, should state: 2) If sample adequacy <br />exists at the reclaimed site, and the production sample mean is less than Q, a <br />"standard null" one-sided t-test with alpha error probability of 0.10 will be used, <br />in conformance with DRMS Regulation 4.15.11(2)(b), using the general form of <br />the one-sided t-test as follows: <br />c) On page (e)-26, a couple changes to the second narrative paragraph are <br />warranted, due to erroneous mention of reference area in the first sentence, and <br />because the wrong West formula is referenced in the final sentence. We <br />recommend the following: 3) If sample adequacy is not achieved, and the <br />following 2 conditions are met: 1) a minimum of 30 sample observations were <br />taken at the reclaimed site and 2) the production sample mean is greater than Q, <br />a "reverse null" hypothesis will be tested using a one-sample, one-sided t-test <br />with alpha error probability of 0.20, in conformance with DAMS Regulation <br />4.15.1](2)(c). The t-testformula used would be the formula listed in Rule