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` 8 When will the material so cover the Terry Tunnel refuse trenches come fmaLp <br /> RESPONSE <br /> Suitable material is available at the Terry Tunnel site for covering the refuse and trash to be <br /> buried. Material will be made available primarily by excavating and grading of the pond <br /> areas and embankment sideslopes. Refuse disposal and reclamation is discussed <br /> previously under question D.15 of this document, and more fully in the Consolidated <br /> Permit Application. A main priority for reclamation at the Terry Tunnel site will be to <br /> reclaim the site without further disturbance of undisturbed areas for borrow or plant <br /> materials. Based on analyses of samples collected from the Terry Tunnel site,presented in <br /> Tables D-2, D-4, the mine bench rock debris appears to be suitable material for <br /> reclamation has been identified at the Terry TunneL <br /> 9. A. Please specVy Terry Tunnel and Amerkan Tunnel pond maintenance pfams and sampling sehedula <br /> following reclamadfon. <br /> B. Indefrnfte mine dminagi dreadneat is not acceptable to tnol reclamad m Pkase devise an aAirrrate <br /> reclamation plan, Passive mine dnafiage dradwent dish may be dedr+uAk Please discuss <br /> C. If At Terry Tunnel was dry uniA7 sAor*g f ter the eoAapm of Lake Emma and V Lake Emrws is to <br /> be properly reclaimed then continued fiowhom this tunnel should be mfnlma Additional work <br /> should be done to determine Vthese flows are surface water and wheeler sealing Lake Emma will <br /> effminate flows. The operator should also lnrestigate chauneAting f ows through the American <br /> tunnel to minimize site maintenance Wn reckmadow. <br /> RESPONSES <br /> As discussed with the MLRD staff at the September 18, 1986 mating,it is anticipated that, <br /> to alleviate the need for indefinite mine drainage treatment, a hydraulic seal will be installed <br /> in both the Terry and American Tunnels. The seal will act to prevent any substantial <br /> releases of underground waters from the tunnels to the ground surface. <br /> Portal closure is planned for the American Tunnel and Terry Tunnels. Detailed plans are <br /> not available at the present and will be developed prior to actual construction. Conceptual <br /> plans would be to place a by-pass pipe for the water flows with a valve in it. A rubble or <br /> concrete temporary bulkhead with supports into the bedrock would then be constructed as <br /> necessary. The valve would then be closed and a plug of concrete placed immediately after <br /> closure to provide an adequate factor of safety against blow-out under full head. (Refer to <br /> Appendix 2-F of the Consolidated Peanut Application) The plug would be placed bacVin <br /> the tunnel so additional hydrostatic pressure will have limited effect on the overburden <br /> rock. <br /> Waters that currently discharge from the tunnels are thought to be from near surface <br /> sources,which infiltrate into fraca res,/joints that penetrate the various workings within the <br /> mine. No specific data related to underground waters within the mine or the sources of <br /> these waters exist for the site. However,based on the physical ground conditions that exist <br /> at mining sites similar to the Sunnyside Mine,certain conclusions can be drawn regarding <br /> potential discharges of impacted mine water to the surface. <br /> Obviously,without any form of hydraulic seal,the tunnels will continue to discharge water <br /> from the mine workings. The source of the water in the workings has to be attributed to <br /> water infiltrating(recharging)front the near surface environment. With the hydraulic seals <br /> -43- <br />