2005-04-12_GENERAL DOCUMENTS - M1999002

Home Browse Search

The original "Ground Water, Surface Water and Process Monitoring Plan" dated December 23, 1999, was adopted as Appendix J of the UIC permit. That plan, referred to as the Water Monitoring Plan, included provisions for baseline monitoring and operations monitoring. Since the implementation of that plan, baseline data collection has been completed and a substantial amount of operational monitoring has been completed. The data collected to date indicate that revisions to the monitoring requirements are warranted to better focus the data collection on meaningful parameters and cost-effective monitoring. The existing data show that some parameters currently measured in the groundwater monitoring program are not useful in determining if mining fluid has migrated into an aquifer. For example, some parameters are not present in the mining fluid at levels that exceed their concentration in the groundwater. Other parameters are consistently non-detectable, and still others are simply unrelated to detecting a migration of mining fluid into an aquifer. Consequently, these parameters are being eliminated from .regular monitoring while retaining those parameters that are present at significant levels in the mining fluid and are useful in identifying an excursion of mining fluid. The current full suite of parameters will continue to be monitored but at a reduced frequency of once per year rather than at each sampling event. The monitoring conducted to date has shown that monitoring water levels (pressure) provides the most direct and timely indication of a cavity leak. Water quality sampling has not shown an immediate response to a leak. Seasonal variation in the water quality data is evident but the month to month variation has been comparatively small: Therefore, during commercial operations, monthly water level monitoring will be maintained while water quality sampling is being reduced to a quarterly frequency. The proposed changes see table 3 which summarizes the wells constituents and freguency of sampling proposed the temporary suspension period) also include modifications to the uses of certain monitoring wells, such as we1120-4 that has shown it is contaminated with cement and should no longer be used for water quality sampling. A monitoring program for temporary cessation periods is also being added to ensure continuous ground-water monitoring even during periods when the permitee is not actively mining. American Soda with input from EPA, BLM and CDMG, developed an updated water monitoring plan that incorporates the above modifications to streamline the monitoring program and focus it on meaningful parameters. American Soda requested that the original Water Monitoring Plan, Appendix J of the permit, be replaced with the updated Ground Water, Surface Water, and Process Monitoring Plan for the Yankee Gulch Sodium Minerals Project, dated September 2004. American Soda L. L. P. began an extensive monitoring program in association with permitting its solution mining project to characterize the ground water of Yankee Gulch in the Piceance Creek drainage.. Baseline monitoring began in 1999, 15 months prior to initiation of Phase I Commercial Production. In cooperation with the EPA, BLM and CDMG, a monitoring network was established that included wells up-gradient, down-gradient, and cross-gradient from the proposed Commercial Production wells located in the 0-5 year mining panel. A chart of relative pump set elevations regarding the monitoring wells is shown in Figure 1, which provides a graphic overview of the various water bearing zones. The wells are grouped according to'the aquifer and zone. Only one alluvial well, Well 19-3, is not represented on this diagram. Well 19-3 is a shallow well down gradient of the proposed site of the evaporation pond. Well 19-3 well is not shown because the pond was never built and the well has never had enough water in it to sample. FINAL Addendum to SOB For Modification No. 9, UIC Area Permit No. C030858-00000 Page 15 of 29