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Each of the footings of the metal structures within the active panel will be surveyed daily. If the subsidence <br />exceeds 1 inch, it will be forwarded to the representative of the joint owners of the line. Presently, it is planned <br />to use a robotic device for the survey work, and if so, it can be programmed to obtain more than one shot per <br />day. The final decision to use this device will depend upon finding a satisfactory location for the instrument, <br />which is outside the subsided area and close enough to differentiate between the targets on the four footers. The <br />survey schedule will follow that given for the above visual inspection program. <br />Wolcott Tap- Wolcott Line <br />Wolcott Tap - Wolcott 230 KV Transmission line - Twentymile will notify Public Services company prior to <br />undermining a structure on this line. The affected structures will be inspected prior to undermining to identify <br />structural deficits, missing or damaged components, loose bolts, and anything else that may affect the integrity <br />of the structures during subsidence. Survey targets will be installed on the structure to monitor subsidence and to <br />record displacement. A PSC patrolman will inspect the structures frequently during the subsidence period. <br />Additionally, Twentymile will be conducting daily visual inspections per the schedule detailed for the <br />Hayden -Gore Pass line. After subsidence and horizontal displacement are essentially completed, the structure <br />will be inspected and repaired as necessary. Per PSC's request, targets will be placed on each leg of the <br />impacted structures and surveyed per the following: <br />1) Begin surveying when the face is 300' from the structures, <br />2) Perform survey every two days until the longwall face is under the structure, <br />3) Survey daily until the subsidence rate decreases to one inch per day, <br />4) Survey weekly until the face is 1,400 feet past the structure. <br />After the longwall is past the required distance and subsidence has ceased, which shows subsidence has <br />decreased to one inch or less since the last survey, the surveying will be terminated. <br />Once the face has progressed 1,500 feet past the structure, monitoring activities will be reduced. For the next 3 <br />months after installation of the reduced monitoring program, visual and instrument surveys will be done on a <br />weekly frequency. Upon completion of this segment of the program, monitoring will be reduced to a monthly <br />frequency for the next six months. After this period expires and two quarterly visual inspections and instrument <br />surveys show no further subsidence, the monitoring program for that panel will end. <br />Western Area Power Administration Line <br />The line will be visually inspected to determine impacts to the line. The visual monitoring program will be <br />conducted on a daily basis when the active longwall face is within 500 feet of the structure. The monitoring will <br />end when the face is 1,500 feet past the structure. <br />Yampa Valley Electric Association Line <br />The line parallels County Road 33 and will be visually inspected on a daily basis. The inspection will <br />commence when longwall mining begins under the structures and will terminate when the longwall face is 1,500 <br />feet past the structures. <br />PR 97 -04 <br />2.05 -191.2 <br />04/15/98 <br />