1995-05-16_REVISION - M1977378 (2)

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05/16/1995 13:02 303-782-0390 CDH WQCD WQCC PAGE 04 Mr.William Goodhard May 12, 1995 Page No. 3 Additional information is nocded on the proposal to fill the mine with alkaline water. While it would seem to be appropriate to accelerate the filling of the mine in order to determine what the impacts are in a shorter time frame, our concern is about over long term water quality impacts. Will the water eventually return to acidic conditions thus creating a water quality impact in the future? Will there be pockets of water in the mine which are not filled by the alkaline water? Has this been done anywhere else with success? The Division needs more inf xmation on this process. We would appreciate information on exactly how it will be done and what measures will be taken to ensure that the water is distributed through out the workings. How will SGC determine if it is working and the estimated time for the water quality to reach equilibrium? Permitting General Permit. The Division is willing to draft a permit for the work on all mitigation sites. We have several permits in a draft stage which would provide the coverage and flexibility you desire. It would require that them be no degradation in the water quality from your activities other than transient impacts associated with construction. However,we do not feel that we could finalize and issue such a permit in the time period you requested. We estimate 60+days to get the permit to a stage where it can be public noticed. We would be willing to cover some of the activities,such as some tailings removal, under stormwater general permits. This would provide SGC with the coverage under a permit in less than 30 days and,therefore,allow some remediation to commence. We could also be working on finalizing a permit which duals with the other sites in question. CDPS/NPDES Permit. The current permits for the American Tunnel,Terry Tunnel and Mayflower miU are expired and have been extended. It would be the Division's intent to maintain these permits until it is agreed that the permits no longer are needed. We do feel that they do need to be renewed so that they accurately reflect the current situation and standards. At this time we anticipate that the requirements to meet BAT will be the appropriate limitations,however we must evaluate the discharge and ensure that any permit limitations are in compliance with foderal and state law and regulations. Has SGC evaluated what the quality of the discharge from the combined Cement Creek/Ame ican Tunnel discharge needs to be to meet the expected loading necessary to have no impact from the tunnel plugging? Concerning the inclusion of WET requirements,the Division feels that for the Terry Tunnel and the Mayflower Mill any discharges need to be in compliance with the WET requirements. Once the American Tunnel treatment system begims to treat Cement Crock,then the Division would agree that WET testing is not appropriate of the combined discharge. The atormiwater requirements state that a permit is necessary until bond release and/or stormwatar no longer comes into contact with mining waste. This permit will be needed until the site mats the regulatory requirements for permit termination.