Operable Unit I Clause Samples

Operable Unit I. OU I consists of the property of the former Monticello mill (mill site) and the waste disposal facility (repository). Solid wastes were removed from the MVP, mill site, and peripheral properties (OU II) and encapsulated at the repository as a remedial action that was completed in 1999. LM owns and manages the repository; the City of Monticello owns the former mill site and manages it as a public park. Monticello NPL Sites FFA Quarterly Report: January—March 2016 U.S. Department of Energy Doc. No. S14013 April 2016 3.1.1 Repository‌‌ Monthly, quarterly, and annual inspections of the repository ensure that remedy controls remain intact and that the waste remains isolated from the environment. Inspection observations and maintenance activities for the quarter are: • No anomalous surface feature conditions were observed for the disposal cell and Pond 4. Surveillance checklists for this quarter are attached as Appendix A. • The disposal cell LCRS and LDS operated as intended. ⎯ Leachate production from the disposal cell was about 800 gallons per week combined for LCRS sumps LCRS 1 and LCRS 2. This collection rate is typical over the past several years. There is no action level for the disposal cell LCRS. See Appendix B for a graphical depiction of leachate production history. ⎯ The disposal cell LDS continues to receive no water; therefore, the disposal cell LDS action level was not exceeded. See Appendix B for a graphical depiction of leachate production history. • Operation of the groundwater remedy optimization system has resulted in increased water collection in the Pond 4 LCRS and LDS. The Pond 4 LCRS and LDS monitoring and pumping systems are functioning as intended to circulate water back to the pond. ⎯ Water collection at the Pond 4 LCRS slightly exceeded the action level during the quarter (see Appendix B). LM has previously notified EPA and UDEQ of this Pond 4 action level exceedance. ⎯ As in recent reporting periods, the Pond 4 LDS received a small quantity of water during the quarter. Although the quantity of water collected in the Pond 4 LDS is well below the action level (see Appendix B), LM is required to notify EPA and UDEQ of any water collection in the Pond 4 LDS. Water quality in Pond 4 and the LDS is known from OU III and groundwater remedy optimization system monitoring data.