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Second Submittal <br /> 7.0 MONITORING PLAN <br /> This modeling effort was completed prior to implementation of the mining process. It is <br /> calibrated to the early summer timeframe. As time goes by and more data are collected, <br /> the model will be updated and verified. The updated model will provide more accurate <br /> predictions and therefore will provide more confidence in the predictive results. The model <br /> can be used as a tool to evaluate water supply and other groundwater related issues during <br /> operations. The model, however, is only as good as the data on which it is based. Thus, <br /> ongoing monitoring of the groundwater is essential. <br /> 7.1 Monitoring Plan <br /> The mining plan for the Pit assumes a ten-year mine life during which the active pit <br /> excavations will be dewatered: Upon closure, a compacted backfill liner with perimeter <br /> drain will exist around the perimeter of the mined area. The backfill liner and perimeter <br /> drain will be constructed congruent to mining. Concerns have been raised as to the <br /> potential for mining activities ancrthe perimeter drain to mobilize selenium. Taking a very <br /> conservative approach(Appendix;F show an example for the southern drain)that selenium <br /> is present everywhere that the Oerimeter drain is installed and it has not leached from the <br /> top 1 cm of the Pierre shale, the resulting concentration in the collected drain water is <br /> estimated at 0.0006 mg/L, which is below the laboratory reporting limit of 0.006 mg/L. A <br /> more reasonable assumption is that the depth to the first selenium is 2.5 feet (depth of <br /> sample). This results in a concentration of 0.000008 mg/L. Regardless, LRM is <br /> committing to monitoring for selenium as described herein. <br /> In addition to this preliminary water quality sampling, LRM has initiated a pre-mining <br /> groundwater monitoring program. The monitoring program consists of monthly depth to <br /> ground water measurements of the 14 on-site monitoring wells. Depth monitoring of on- <br /> site monitoring wells will shift to quarterly schedule after one-years' worth of data are <br /> collected and until active operations are completed. One round of neighborhood well depth <br /> to groundwater measurements were taken. LRM is reaching out to inquire about a February <br /> neighborhood round of depth measurements. <br /> Loveland Ready-Mix Concrete 24 Telesto Solutions,Inc. <br /> 20180112 grrowiawat—twly_21KJ%ubwwnld­ Januarv2018 <br />