Laserfiche WebLink
statistical confidence using the equation: y= 0.0173x ^3 - 0.8592x ^2 +14.56x- 47.015, where x is the <br />cumulative value of precipitation from September to July of the following year, and y is the resultant <br />vegetation cover." This cover standard is in agreement with Rule 4.15.8. <br />The Keensburg Mine permit had previously utilized comparison of an approved reference area (Rule <br />4.15.7(3)), known as the Osgood reference area, for revegetation success of the reclaimed areas. <br />Comparison of the Osgood reference area was not ideal due to a successional change of species <br />composition in the reference area to a community heavily dominated by sand sagebrush and a reduction <br />of forage grasses and forb species over the years. A change in surface ownership of the property upon <br />which the reference area was located caused concerns regarding management of the reference area. The <br />permittee proposed revegetation success standards for vegetative cover and herbaceous productivity <br />based on a formula derived from historic data collected on the Osgood reference area and correlation to <br />precipitation records (TR37, approved June 15, 2006). <br />Cover <br />Vegetative cover data was collected in August 2009 and in August of 2010 in accordance with the <br />methodology approved in the permit and Rule 4.15.11(1). Precipitation is measured by CEC at the <br />weather station located near the mine office. Precipitation measurements between September of 2008 <br />and July of 2009 totaled 13.71 inches as reported on page 11 of the 2009 Quantitative Vegetation Study <br />submitted with SL -06 and reported in the 2009 Annual Hydrology Report. Calculation of the required <br />vegetative cover standard for 2009 using 13.71 inches of precipitation resulted in a reclamation success <br />cover value of 35.69 %. Ninety percent of this calculated value is 32.12 %. <br />Total precipitation from September of 2009 to July of 2010 was measured to be 14.65 inches as reported <br />on page 7 of the 2010 Quantitative Vegetation Study submitted in SL -06 and reported on page 12 of the <br />2010 Annual Hydrology Report. Calculation of the required vegetative cover standard for 2010 using <br />14.65 inches or precipitation resulted in a reclamation success cover value of 36.28% Ninety percent of <br />this calculated value is 32.65 %. <br />The permittee sampled nine parcels as one bond release block (BRB) based upon the date of seeding. <br />The block was comprised of parcels seeded between 1998, 1999 and 2000. These parcels consisted of <br />Reclamation Areas 2,5,6,7,9,10,15,16, and 19. CEC reports the mean total vegetative cover for 2009 <br />was 60.96 %. and the mean total cover for 2010 was 51.91%. CEC included cover attributed to annuals <br />and noxious species in the total cover values. The Division is unable to allow plant species listed on the <br />State Noxious Weed list (Department of Agriculture, Conservation Services Division, 8 CCR 1206 -2: <br />Rules Pertaining to the Administration and Enforcement of the Colorado Noxious Weed Actl) to <br />contribute to reclamation success. The Division Guidelines; Guideline Regarding Selected Coal Mine <br />Bond Release issues, April 18, 1995, specifically state that, "under no condition will noxious weeds <br />count towards the success standard. The cover and production component provided by noxious weeds <br />should be deleted from both reference and reclaimed area data prior to success comparison for those <br />parameters. <br />Correction of CEC's data to remove cover contributed by noxious species as defined by Weld County <br />Weed Program and Colorado Department of Agriculture, results in 52.66% live vegetative cover for <br />Page 5 <br />