1982-08-24_GENERAL DOCUMENTS - C1981013 (5)

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Maxwell Mine File No. C-01 3-81 Response to Draft Findings Document XXIII . SUBSIDENCE - RULES 2 .05 .6(6) AND 4 .20 CF&I will visually monitor the two overhead powerlines, the Colorado & Wyoming Railroad, and the State Highway for any possible subsidence effects on a quarterly basis . The inspections will be made along those reaches of these structures that lie within the area of influence (projected using a 30- degree angle of draw) of all mined areas . Visual observations will be made for variance in alignment, settlement, heaving, cracking, or other visual signs which might indicate subsidence. The buried telephone cable is not amenable to visual inspection. The Purgatoire River and its associated aquifer would produce an immediate effect in the mine if adverse subsidence would occur. Monitoring is continuous on this point in that the mine workings are under constant observation even when the operation is idle. With respect to stipulation No. 2 requesting an additional alluvial monitoring well above the first North Mains , we suggest any affect would be noted in the mine and that this would be observed sooner than periodic well monitoring. Should damage occur to the Trinidad City water supply pipeline due to subsidence affects caused by the underground mining, CF&I will immediately initiate the necessary repairs . Personnel with the necessary skills and the required equipment to do the work are readily available at the Allen and Maxwell mines. This structure lies within the limited extraction area for the mine and subsidence effects if any, will be slight. CF&I would like to point out that the license agreement between "The City of Trinidad" and CF&I for the pipeline includes language protecting CF&I ' s right to "full use" of the land, and "save harmless" for damage for that portion of the pipeline which lies on CF&I ' s ownership. Photocopy of the appropriate sections of this License Agreement are attached. Notwithstanding, CF&I does commit to the plan for immediate repair as stated in the above paragraph. CF&I will take premining photographs of structures 8, 15 , 26 , 29 , and 30. These structures are identified in Table 17 and on Map 17 of the permit application. These photos will be taken before the area of influence of mining extends to include these structures. Subsequently, these structures will be visually inspected on a quarterly basis for changes which may result from subsidence.