REP08161 - Laserfiche WebLink

Home Browse Search

The survey data for the Water nine Monuments indicate that sub- sidence is occurring only at Monument "E" at the rate of 9.14 feet for the reporting period. Total displacement at the point is 1.52 feet to date. It is anticipated that minor subsidence will continue at Monument "E" as ground conditions continue to consolidate above the retreat mining area. This report also contains the first data obtained from four new water line monu- ments, "F" through "I", established as required in the 4m acre Incidental Boundary Change permit addition. The new monuments, as shown on Table 2, do not indicate any subsidence. Newlin Creek Monument Survey data for Newlin Creek Monument are presented on Table 3, Subsidence Monitoring Data Summary. There was no mining activity to impact this monument during this reporting period. No additional subsidence was detected at the Newlin Creek Monu- ment for the period of this report. Total subsidence to date is 0.62 feet, and continued subsidence is expected to be minimal. Thompson Ranch Structures All survey data pertaining to the Thompson Ranch Structures for the period of record is shown on Table 3, Subsidence Monitoring Data Summary. No subsidence was detected on the three structures for the re- porting period. This condition is consistent with information provided in previous semi-annual reports. It is anticipated that there will be only minor additional subsidence at the site of the structures. Conclusions The required subsidence monitoring program continues to provide information necessary to evaluate the magnitude of subsidence on structures and the high-resolution monitoring grid. No structur- al damage has been observed on the monitored structures. It is anticipated that continued subsidence at monitored structures and at the high-resolution grid will be minor, and total subsidence will be within maximum worst cast values predicted in the mining permit.