PERMFILE114605 - Laserfiche WebLink

Home Browse Search

Table 72 B, NMD Rechazge Time Estimate, provides the number of days it would take to fill th the additional fracture volume resulting from subsiding the bedrock. Again, it should be recognized that this is a very conservative estimate due to the character of the stream. The data presented assumes that sandstone bedrock can be found for the entire length of Fish Creek overlying the panels and this is not the case. The section in which the sandstone unit is exposed is the approximate 1260 feet of channel in section l0, TSN, R86W. The remainder of the channel is alluvial material overlying the Lewis Shale. Given the nature of the shale it will swell to fill in any cracks that may occur. The amount of time necessary to fill in the additional fracture volume varies from 0.6 days to 17.4 days for panel 13 Right, depending upon the time of year mining and subsequent subsidence occurs. For panel 14 Right the amount of time required to fill the fracture volume varies from 0.3 to 7.9 days, panel 15 Right varies from 0.2 to 6.2 days, panel 16 Righ[ varies from 0.2 to 6.8 days. Twentymile is the immediate downstream user of irrigation water and does not foresee any impacts to its agricultural operations due to the potential loss of water form the system. th the event that significant losses occurred during the irrigation season Twentymile has sufficient water rights to augment and loss. th reference to water quality impacts, the ongoing downstream monitoring at station 900 on Foidel Creek does not show any changes that can be attributed to subsidence over panels 8 and 9 Right. The reader is referred to TCC's 1996, 1997, and 1998 Annual Hydrology Reports to review this data. Table 37A, Foidel Creek Flow Analysis after Subsidence in the EMD, shows that water is not being lost to segments of the Foidel Creek that have been undermined and subsided ta the EMD. This is based on comparing site 800 plus ponds to site 900. The site 8 data is not being used in the comparison due the discrepancy in the data for site 800 and Ponds B, D, E, F, and G. The total flow from site 800 plus the ponds should approximate the flow recorded at site 8. TCC is investigating the discrepancy and will make changes to site 8 as needed. • In order to validate that no impacts will be realized to the AVF located downstream of its operation, TCC will continue to utilize its current downstream surface and alluvial water monitoring stations. These stations are presented on Map I3A, Hydrologic Monitoring Program. The stations will be monitored as per the existing monitoring schedule. These stations are located along Fish Creek th Section 5, TSN, R86W. In addition to the current hydrologic monitoring program, TCC will initiate a program directed at the segment of Fish Creek to be impacted by mining in the NMD. This environmental program is presented in Exhibit 4e-7, NMD- Fish Creek AVF Monitoring Program. The program includes the following components: hydrologic monitoring, vegetation monitoring, and subsidence surveying. • APp~~~~~ JUN 2 ~ 200 PR 99-OS 2.06-25.4 l 1/17/99