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<br />f <br />the consequences of rupture are environmentally acceptable and will not <br />result in material damage. Figure 60, entitled "Subsidence Contours - <br />5 Year Mining", depicts 7.5 feet of projected surface lowering above <br />longwall panel No. 1 of the No. 6 (4ine, in the vicinii:y of the <br />pipeline. Subsequent panels will repeatedly expose ttie pipeline to <br />deflection and strain. Analytical techniques are available with which <br />to project the bending moments and strains to which the pipe might be <br />exposed. In turn, the design implications for these mechanical <br />conditions can be determined for the pipeline. AMOCO should be <br />informed of the applicant's proposal to subside the pipeline. It <br />should also be possible, with the cooperation of At40C(l, to project the <br />environmental consequences of a rupture, as well as the necessary <br />cleanup and repair activities required in the event oi' a failure. The <br />applicant will have to complete these steps before permission to <br />subside the structure could be granted. Similar analyses have been <br />completed in relation to other underground mine appli<:ations within <br />Colorado. <br />2. The application states, on page 2.05.6(6)-45, that the applicant <br />proposes to maintain abandoned County Road 107 as necessary for its own <br />use. County Road 107 is proposed to be undermined during the first <br />five year permit period. This will probably be accept;able, if the <br />appropriate steps are taken to control exposure of the public and <br />company personnel to hazard from subsidence damage. Erection of signs <br />warning of the potential hazard, controling access to the road, and <br />periodic visual inspection could be appropriate components of a <br />subsidence control plan for County Road 107. <br />3. The applicant proposes to subside State Highway 13 during the <br />life-of-mine of the Eagle No. 6 mine. No subsidence •is projected to <br />occur during the initial five year permit period. The applicant's <br />proposal to subside State Highway 13 may not approvable under the <br />regulations. Rule 2.07.6(2)(d)(iv) specifically prohibits surface coal <br />mining operations within 100 feet, measured horizontaVly, of the <br />outside right-of-way boundary of any public road, unless the applicant <br />possesses a valid existing right as of February, 1977„ or the applicant <br />proposes to relocate the road. Ground surface subsidence resulting <br />from underground coal mining constitutes a surface coal mining <br />operation. Because the applicant does not propose to relocate State <br />Highway 13 mining which would cause subsidence within 100 feet of the <br />right-of-way boundary cannot be approved, unless the applicant <br />demonstrates a valid preexisting right or proposes an acceptable <br />relocation plan.. <br />Assuming this apparent prohibition could be overcome, significant <br />technical concerns would have to be resolved before any permission <br />could be granted to undermine State Highway 13. The application <br />states, on page 2.05.6(6)-13; "The worst possible consequence of <br />life-of-mine subsidence on State Highway 13 would be a slight lowering <br />of the grade and the development of surface cracking 'in the pavement." <br />However, on page 2.05.6(6)-22, the applicant observes that surface <br />lowering and cracking have been observed above existing longwall panels <br />No. LW-1 8 LW-2 in the No. 5 mine. Surface lowering has reached a <br />maximum vertical magnitude of 4.8 feet, while surface cracks have <br />