REV93163 - Laserfiche WebLink

Home Browse Search

criteria for the site be met in at least the last two consecutive years of the extended (ten year) liability period. Cover: The approved cover standard for the mine requires that "Vegetative cover will be restored on the reclaimed area to at least 90% of the vegetative cover as that on the approved reference area." Based on review of the data collected in year nine (1998), the cover standard was achieved. The permittee chose to analyze the vegetative cover data eliminating the annual and biennial species component from both the reference area data and the reclaimed area data. This method is acceptable and is suggested in the Division's "Guideline Regarding Selected Coa! Mine Bond Release /ssnes", dated April I8, 1995. Reference area vegetative cover collected in June 1998 was 25.07 %. Ninety percent of the reference area cover is 22.56%. The reclaimed area cover measured 23.44% during the June 1998 data collection. The permittee successfully demonstrated that the reclaimed area cover is greater than 90% of [he reference area cover with a 90% confidence interval. The cover standard was again achieved for the 1999 (year ten) based on review of the data collected. As done with the 1998 data, the permittee analyzed the vegetative cover data by eliminating the annual and biennial species component from both the reference area data and the reclaimed area data. Vegetation cover data were collected in July 1999 on both the reference area and reclaimed area. The reference area vegetative cover for 1999 was 21.87 %. The reclaimed area cover measured 24.67 %. The permittee successfully demonstrated that the reclaimed area cover was greater than 90% of [he reference area cover for the last two years of the liability period. No additional statistical evaluation was necessary. Productivity: The approved productivity standard for the mine requires that herbaceous productivity be restored to at least 90% of the production of the approved reference area. Herbaceous productivity measured on the reference area was 238 lbs./acre in 1998 (yeaz nine) and 199 lbs./acre in 1999 (year ten). Productivity data on the reclaimed areas was highly variable. Kaiser was not able to achieve sampling adequacy after collection of 50 production quadrats for both 1998 and 1999 data. Kaiser analyzed the productivity data using non-parametric statistical methods. The analysis methodology is acceptable to the Division. These data collected on the reclaimed area in 1998 have anon-normal distribution, as do the 1999 data. Using non-parametric statistical analyses, the operator determined that the median of the