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RE: L. G. Everist, Inc., Fort Lupton Sand and Gravel Mine, DMG #M-1999-120; <br />Second Adequacy Response Letter <br />Exhibit G -Water Information <br />3. Geologic information [on] ...bedrock in the area...installation of slurry walls <br />LGE commits to submitting geologic information on bedrock as part of the required slurry wall <br />construction information with each Technical Revision that we will submit prior to bonding for a <br />new phase. Our experience thus far with the original permitted area has shown that the <br />geologic make-up of the bedrock in the area are sufficient for proper slurry wall installation. Our <br />current pit has a slurry wall installed that has been approved by the State Engineer's Office <br />(SEO). <br />4. Commit to measures to be taken if trigger points are reached <br />If a trigger point is reached and either a complaint is received or if monitoring of vegetation <br />indicates a hydrologic imbalance, LGE commits to starting the assessment of the situation <br />immediately. If LGE operations are found to be the cause of the groundwater level change, <br />LGE commits to implementing appropriate mitigation measures to equalize groundwater levels <br />and/or alleviate adverse effects of any groundwater level changes felt off-site within 60 days of <br />reaching a trigger point, except as described below. <br />If there are adverse weather conditions, or if mitigation measures to be implemented are large- <br />scale (i.e. french drain), and require more design and construction time, LGE will propose a <br />mitigation schedule to the Division and affected landowner within 60 days of reaching a trigger <br />point to determine a reasonable completion schedule. If the case is an emergency situation (i.e. <br />domestic well-goes dry), LGE commits to emergency temporary mitigation (i.e. supplying water <br />via a portable tank) while still assessing the cause; and if it is determined that LGE is the cause, <br />more permanent mitigation measures will be completed. <br />To reiterate and add to the list from the WWE report, following are some mitigation measures <br />that LGE will implement if LGE operations have caused groundwater levels to hit a trigger point, <br />as appropriate to the situation: <br />- construction of a pipe/drain to equalize groundwater levels <br />- release of water in ditches/laterals (Note: LGE will get proper agreements with ditch <br />and/or landowners prior to release of any release of water.) <br />- well improvements (i.e. deepening and/or relocation) and/or well replacement <br />- planting of trees, shrubs, vegetation <br />- as mentioned above - in "emergency" situations, prior to full assessment, LGE will <br />supply water via a portable tank or other method <br />Please note that this is not an exhaustive list, and if a situation arises that calls for a different <br />mitigation measure, LGE will work with the injured party and the Division to formulate an <br />appropriate mitigation plan. <br />5. At least a year's worth of groundwater data... <br />LGE commits to gathering and submitting to the Division via a Technical Revision (TR), at least <br />one year of groundwater monitoring data, prior to installation of a slurry wall in the amendment <br />area. <br />LM/FL-Resp2ndAdegRev-dmg KP-012105.doc <br />