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May 11, 2011 Page 14 <br />of horizontal strain for paved roads are 1 -3 millistrains and allowable slopes are 0.5% to 1 %. <br />These levels of ground disturbance should not affect unpaved roads as intensely. Room -and- <br />pillar development may be performed under unpaved roads without any perceptible impact. <br />4.11.2 Unpaved Road Monitoring Plan <br />plan: <br />To ensure that the control plan is effective, AAI recommends the following monitoring <br />• The structure owner(s) should be informed as mining approaches. <br />• Due to the low probability of perceptible surface deformation, no direct monitoring is <br />required. Structural anomalies reported by the surface owner(s) will be investigated. <br />4.11.3 Worst Possible Consequences of Damage to Unpaved Roads <br />Horizontal strains in excess of the allowable strain levels could create cracks, heave, <br />slumps, significant changes in gradient, etc. All of these factors could deteriorate the road <br />surface, possibly adversely affecting driving conditions or road utility. <br />4.11.4 Unpaved Road Damage Mitigation Plan <br />In case monitoring indicates onset of damage or potential for damage to unpaved roads, <br />the following mitigation plan should be adopted. <br />• Appropriate personnel at mine and regulatory authorities should be informed in case <br />anomalies are observed that may indicate an affected road segment. <br />• The mining plan should be re- evaluated to ensure that operations will not further damage <br />the road segment in question, or an agreement should be reached with the road owner that <br />such damage is acceptable as long as it is repaired. <br />4.11. S Paved Road Subsidence Control Plan <br />The only paved road that passes over any planned mine workings is SH 12 highway. The <br />allowable levels of horizontal strain for paved roads are 1 -3 millistrains and allowable post - <br />deformation slopes are 0.5% to 1 %. The workings underneath the road need to be development - <br />only with pillars with long -term stability, as estimated using ARMPS. <br />4.11.6 Paved Road Monitoring Plan <br />plan: <br />To ensure that the control plan is effective, AAI recommends the following monitoring <br />The State of Colorado should be informed as mining approaches and data generated <br />during monitoring should be shared with the State. <br />Paved road segments overlying the underground workings should be monitored by <br />establishing appropriately located survey points spaced at no less than 500 ft apart. <br />Agapito Associates, Inc. <br />