GENERAL35570 - Laserfiche WebLink

Home Browse Search

American Soda has collected and analyzed samples from the collection points in the solution mining streams at both the upper and lower well field production gathering lines and the injection stream going into the wells on a monthly basis since commercial operations began. These data represent the constituent concentrations of fluids that would be available to migrate into the overlying aquifers in the event of a cavity breech or mining into a fault or fractured zone. The concentration of the constituents in the solution mining brine shows some key indicators that aze mazkedly greater in concentration when compared to the various concentrations of these same constituents derived from the overlying aquifers. In other words, it is expected that in the event of contact between the brine solution and the overlying aquifers, analysis of these indicator parameters in the ground water system would show evidence and extent of contamination from brine solution as a result of the compazative concentration differences. As monitoring proceeds, the analysis of monitoring data may indicate that further changes to the Water Monitoring Plan are warranted. To allow EPA and American Soda the best opportunity to adapt the monitoring requirements to respond to future monitoring needs and conditions that maybe encountered in the field, American Soda has requested that EPA allow for future modification of the Water Monitoring Plan as a minor modification to the Permit. Specific changes to the monitoring plan that would be accomplished as a minor modification to the Permit would occur only after a review of monitoring data and an assessment the ongoing monitoring needs. Such changes could include: • specific monitoring parameter changes, including the addition, deletion, or substitution of specific parameters • changes to sampling methods that would improve the ability to consistently and reliably obtain representative samples • changes to laboratory analytical methods that would improve the accuracy, reliability, or comparative value of the results • changes to the frequency of monitoring, including an increase or decrease in the frequency of monitoring at any or all monitoring locations • modifications to the location of monitoring points, including the addition, deletion, or substitution of specific monitoring wells or well completion zones Reduction of the current monitoring requirements would be made only after a review of the data demonstrates that the current monitoring requirements are: 1) redundant For example, where other monitoring locations or data already provide adequate monitoring coverage, a reduction in monitoring could be appropriate. 2) not producing reasonable data quality or quantity For example, where a monitoring well appears to be contaminated or does not produce enough water to be consistently sampled, or in a case where data for a specific parameter is not adding any substantive value to the monitoring program, a reduction in monitoring could be appropriate. 3) cannot reasonably be continued due to field conditions or technical considerations For example, in a case where high TDS concentrations in a well continually foul automatic recording equipment installed in the well or where a blockage in a wellbore precludes sampling the well, a reduction or substitution in monitoring could be appropriate. 4) not cost-effective relative to the value of the monitoring information For example, where other less costly methods provide a similaz data quality and monitoring value, a substitution of methods could be appropriate. Draft Addendum to SOB For Modification No. 9, UIC Area Permit No. CO30858-00000 Page 21 of 27