2011-05-18_PERMIT FILE - C1981012A ‎(2)‎

• Permit No: C1981012A
• IBM Index Class Name: Permit File
• Doc Date: 5/18/2011
• Doc Name: SUBSIDENCE CONTROL, MONITORING, AND MITIGATION PLAN
• Section_Exhibit Name: Exhibit 24 Subsidence Control, Monitoring, and Mitigation Plan
• Media Type: D
• Archive: Yes

May 11, 2011 Page 19
4.14.3 Worst Possible Consequences of Damage to Alluvial Valley Floor
Although unlikely, subsidence damage to alluvium could alter the river bed morphology
by creating large cracks and craters. This may lead to the onset of river bed erosion and loss of
alluvium from the affected areas.
4.14.4 Alluvial Valley Floor Damage Mitigation Plan
In case monitoring indicates the onset of damage or potential for damage to the alluvium
on Purgatoire River bed, the following mitigation plan should be adopted.
Appropriate personnel at mine and regulatory authorities should be informed in case
anomalies are observed that may indicate the alluvium being affected.
• The underground development plan should be re- evaluated to ensure that operations will
not further damage the river bed alluvium.
Agapito Associates, Inc.