Laserfiche WebLink
r <br />11~litigation/Contingency Plan for Subsidence of the <br />• Hayden -Gore Pass 230/345-kV Transmission Line <br />On July 13, 1995, the technical committee met at the Western Area Power Administration <br />(Western) Golden Office to finalize a proposed contingency plan to mitigate the mine subsidence <br />across l3 structures of the Hayden-Gore Pass 230/345-kV transmission line. Approximately one <br />tower will be subsiding on this transmission line each year for the next l3 years. This <br />contingency plan affects the 11 structures for which Twentymile Coal Company has superior <br />land rights. There are two structures on the transmission line in which Tri-State Generation and <br />Transmission has superior land rights. The cost of mitigation on these two structures will be <br />borne by the coal company under a separate agreement. The following contingency plan was <br />forwarded to the Engineering and Operations (E&O) Committee by the technical committee. On <br />July 10, 1996, the E&O Committee reviewed and then approved the following plan. <br />1. Western will throughly inspect each tower prior to subsidence to identify: <br />a. Structural defects <br />b. Missing/damaged parts <br />c. Loose bolts <br />• d. Stressed members <br />e. Any other visible condition which might impact the tower response to subsidence <br />2. Westem, Tri-State Generation and Transmission, and Public Service Company of Colorado <br />will have work crews and equipment available to repair [he transmission line, and the <br />following supplies will be on hand: <br />a. Materials for three 230-kV wood H-frame structures and two 3-pole dead-end structures <br />includine insulators and hardware. <br />b. Equipment for installing the 230-kV structures including guys and guy anchors. <br />c. 6,000 feet of 1272 kcmil, 45/7, ACSR, "Bittern" conductor. <br />Western will supply the structures, hazdware, insulators, guys, and guy anchors from the <br />existing maintenance agreement funds. <br />3. The first tower will be subsided and the structural damage accessed. If the damage is limited <br />to minor structural members, i.e., bent, tension pullout, etc., the tower will be repaired <br />through the regular maintenance agreement. If the damage is major, the structure will be <br />• replaced with the wood poles in item 2.a. <br />