2007-06-06_REVISION - C1996083 - Laserfiche WebLink

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subsidence control plan for the Bruce Park Dam and the Terror Creek Reservoir be included under Rule 2.05.6(6)(f). Therefore, the original statement that BRL will repair any mine-related damage and be responsible for damage to injured parties as it relates to the Bruce Park Dam needs to be put back into the permit application under Rule 2.05.6(6)(f)(iv). In addition, the USDA-Forest Service is requesting, in their letter dated February 22, 2007 which is attached, that BRL add a statement on page 2.05-103 concerning the USDA-Forest Service Special Use Authorization to the Terror Ditch and Reservoir Company for the Bruce Park Dam. 24. Under Rule 2.05.6(6) (f)(v) (A) on revised page 2.05-114, it is stated that the pre-subsidence survey for the Terror Creek Reservoir dam structures can be found in Volume X. However, the information in this volume is quite extensive. Please revise page 2.05-114 to reference the exact reports and page numbers in Volume X that pertain to the pre-subsidence survey mentioned on revised page 2.05-114. The information contained in the pre-subsidence survey must be detailed enough to determine the degree of material damage or diminution of value of the dam structures should it occur. In their December 28, 2006 response, BRL stated that the two geotechnical reports in Volume X are the pre-subsidence survey. However, the Division believes that the information that is presented in Volume X is not adequate. The information in Volume X defines the general geometry and geology, as well as the subsurface geotechnical characteristics, of the dam structure, but it does not define and document the present condition of the dam. If damage, such as cracks, bulges or slumps, should be discovered on the dam after mining has passed, BRL will not be able to show that the defects were pre-existing. A pre-subsidence survey would document if such damage currently exists. Please consider submitting a pre-subsidence survey for the Bruce Park Dam. 25. On revised page 2.05-117, under Rule 2.05.6(6)(f)(v)(B), mention is made ofthe seismic monitoring program. However, the purpose of this monitoring program is to measure the strength ofthe seismic wave at various points, not to measure whether there has been an effect of the seismic wave, or of subsidence for that matter, on the two dam structures. In support of the Rule 2.05.6(6)(0(v) requirement for a description of the measures to be taken to determine material damage or diminution of value, please propose a monitoring program that will demonstrate baseline conditions and measure the structural effects ofsubsidence and seismicity on the Bruce Park main dam and saddle dam. BRL responded that the seismic monitoring program that BRL has set up has a different approach than what the Division had described. BRL's plan is to measure the magnitudes of the mining-induced seismic events and compare them to the seismic event limitations determined by the GEI Consultants report for the Bruce Park Dam and saddle dam and adjacent landslide. Please provide a detailed description of the exact plan BRL intends to use to show that mining can occur within one mile of the Bruce Park dam and saddle dam. The description should include the overall methodology framework, what parameters will be measured in the field, how those parameters will be converted into useable data for analysis, how the analysis will be performed, how the data and analysis will be presented in the seismic reports and how conclusions will be drawn from the analysis. 26. The Division understands that the seismic data currently being gathered at the Bowie No. 2 Mine will be provided to the Division as part of the PR-10 adequacy review. The Division would like to receive the preliminary seismic data as soon as possible to see what magnitudes are being generated by the mine. The adequacy review will progress more smoothly and more efficiently if BRL, the Division and 7