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-2- (1) Subsidence Monitoring Programs as described in Rule 2.05.6(6)(c> are specifically required by Rule 2.05.6(6>(b)(fi) to confirm the permittee's conclusion that no material damage or diminution of reasonably forseeable use could result from the permittee's operations within the permit area and adjacent area. Failure by Twentymile Coal Company to conduct its Subsidence Monitoring 'mil Program in accordance with the rules and the permit has now created a ,((~-U' situation whereby the permittee's conclusion regarding material damage ~" ,S may be statistically unverifiable. ,4 _ L~S k'`' ~ I find therefore that the event Rule 2.05.6(6)(c)(i)(D) is designed to (_',vJ,~y,~" prevent, namely a permittee's failure to obtain baseline data to prove the permittee's material damage conclusion, has occurred. (2> The duration and extent of actual damage, in terms of area and impact on the public or environment, is not known at this time. It is apparent, however, that the permittee's expectations regarding the subsidence-related draw angles were all underestimated, as empirical data from the permittee's "First Half Subsidence Monitoring Report, 1993" has ~~`~ demonstrated that actual draw angles are anywhere from 2 to 20 degrees greater than expected. ~` L~Jar What is more significant is that Twentymile Coal Company is mining beneath the Fish Creek Alluvial Valley Floor. It is assumed that subsidence of the AVF was granted by the Division pursuant to the 'r operator's conclusions regarding lack of material damage to the AVF F (Rules 4.24.1, 4.24.2, and specifically 4.24,3(3)). ,1~~"~ `r ~~~~ ~~ ~~ However, as the subsidence monitoring program has been conducted J w~, ~~~~ erroneously, the conclusion regarding the lack of material damage may be o ~(',~." unsupportable, and the potential for damage to the Fish Creek AVF now appears to exist. The permittee's comments that "one should ideally complete baseline surveys as close as possible to the start of active subsidence, thus providing a minimal opportunity for other surface activities to impact the subsidence baseline" were considered as unsupportive in justifying the permittee's actions. The permit and the Rules specifically require monitoring to commence one month prior to the commencement of mining beneath established monuments. To provide for both regulatory compliance and the permittee's ideas regarding protection of the subsidence baseline from "other surface activities", the permittee should have monitored the baseline weekly, staring one month prior to mining, and monitored immediately before mining commenced.