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October 11, 2011 <br />4.11.5 Paved Road Subsidence Control Plan <br />Page 25 <br />The only paved road that passes over any planned mine workings is State Highway (SH) <br />12. The allowable levels of horizontal strain for paved roads are 1 -3 millistrain and allowable <br />post - deformation slopes are 0.5% to 1 %: The workings underneath the road need to be <br />development -only with pillars with long -term stability, as estimated using ARMPS. <br />4.11.6 Paved Road Monitoring Plan <br />To ensure that the control plan is effective, AAI recommends the following monitoring <br />plan: <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 />• Annual surveys should be conducted for the service life of the highway. Visual <br />monitoring should be performed on the roads. Any appearance of cracks, heave, slumps <br />or steep gradients in the roads should be noted. <br />• Structural anomalies reported by the State will be investigated. <br />4.11.7 Consequences of Damage to Paved 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 />4.11.8 Paved Road Damage Mitigation Plan <br />In case monitoring indicates the onset of damage or potential for damage to paved roads, <br />the following mitigation plan should be adopted: <br />• Appropriate personnel at mine and regulatory authorities, as well as the owners of the <br />road, should be informed in case anomalies are observed that may indicate an affected <br />road segment. <br />• Re- grading and resurfacing should be applied to affected road segments. <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 />Agapito Associates, Inc. <br />