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Phil Jensen <br />• 9 Oct 97 <br />Page 9 of 18 Pages <br />Mr. Jensen stated in his letter to the Division of Minerals and Geology, dated September 12, <br />1997, that, "building roads and drill sites made a nice seed bed and the seeds were carried on the <br />machinery and planted." Enron submitted a letter from the Rio Blanco Weed Supervisor ,dated <br />November 16, 1990, into the permit (pages M-12V and Ml2W). In this letter the county weed <br />supervisor states, "I'm sure all these weeds [Leafy spurge, Canada thistle, Houndstongue, <br />Mullein, and Bull thistle] were present prior to mining operations. The 9 Mile area has the <br />largest concentration of Leafy Spurge in the County and as faz as I can tell was introduced into <br />that area in the late 1800's and early 1900's." This statement by the local weed district indicates <br />to the Division that Enron is not the cause for the presence of these weed species on the old <br />exploration roads or reclaimed pads. <br />Investigation into the baseline data (Appendix K) finds noxious weed species presence in the <br />permit area prior to disturbance by the mining operation. This data was collected during July, <br />August and September 1979. Noxious species encountered in the baseline survey include; <br />Canada thistle (Cirsium arvense), and Leafy spurge (Euphorbia esula). These species accounted <br />for an average on 0.5% absolute cover throughout the sampled areas. Although not listed on the <br />Rio Blanco County or State of Colorado noxious weed lists, both "Yellow" thistle (Cirsium <br />ochrocentrum) and Curly-cup gumweed (Grindelia squarrosa) [a.k.a Rosinweed] were <br />encountered in the baseline data. Consequently, a minor presence of these species in the <br />reclaimed areas is not unexpected. <br />Review of the vegetation data collected during 1995 and 1996 for the bond release inspection, <br />finds that noxious weeds, Canada thistle and Leafy spurge, accounted for 0.7% absolute cover <br />and 0.8% absolute cover for the respective yeazs. The cover contributed by these noxious species <br />was not factored into the perennial non-noxious cover value for the reclaimed aeeas. The data <br />from 1995 and 1996 indicate that the weed presence is not significantly increasing. <br />Rule 2.05.4(2)(e)(v) specifies that the revegetation plan contained within the permit application <br />contain description of any "pest and weed control measures" to be employed. Once a noxious <br />weed concern was identified on the reclaimed site, Enron regulazly exercised a weed <br />management program. These measures employed by Enron aze found on permit pages M-13 <br />through M-13B. Enron has further documented their weed control efforts by inclusion of billing <br />receipts from Rio Blanco Weed and Pest Control dating from 6/16/87 through 1995. <br />The Division finds that Enron has performed weed management in agreement with the Division <br />guidelines and Rule 2.05.4(2)(a)(I). Rule 4.18(5)(g) specifies that persistent pesticides not be <br />used unless approved by the Division. In accordance with this Rule, Enron used Banvel and <br />Tordon which are non-persistent in the soil. The Division does not find that Enron would be <br />required to continue weed control beyond the period of liability, based upon vegetated data <br />. Enclosure 3 <br />