GENERAL42468

• Permit No: C1980007
• IBM Index Class Name: General Documents
• Doc Date: 8/26/1985
• Doc Name: Proposed Decision & Findings of Compliance for PR1
• From: Addition of 1,630 Acres
• Permit Index Doc Type: FINDINGS
• Media Type: D
• Archive: No

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the Division has imposed a stipulation defining the accuracy standards
to be achieved in completing both the field and aerial photogrammetric
pre-subsidence surveys.
Further, the Division believes the photogrammetric subsidence
monitoring technique to represent an interesting potential technical
innovation. However, the technique is unproven for the completion of
subsidence monitoring surveys. Therefore, the Division believes it
prudent to require the applicant to correlate its aerial
photogrammetric monument surveys to traditional ground survey
monitoring of selected triangulation monuments. In order to avoid
misunderstanding, the Division has imposed a stipulation defining the
accuracy standards to be achieved in completing post-subsidence aerial
photogrammetric surveys of the subsidence monumentation grid.
Subsequent to the original submission of exhibit 3.4.8.A, the Division
addressed additional concerns to WECC regarding the possible effects of
subsidence upon landslide deposits neighboring Beaver and Minnesota
Reservoirs. WECC responded in letter form indicating that it desires
that the final designation of possible additional "safe areas" of
limited extraction be tied to the detailed results of the analysis
being performed upon the landslide deposit above the Town of Somerset.
In February of 1985, WECC submitted a permit..revision application
requesting the addition of 1,630 acres to its permit area. This
revision appplication proposed the expansion, of the mine plan, limited
to areas north of the Minnesota Creek surface and ground water divide.
In response to Division adequacy review comments, WECC clarified and
amended the original revision application mine plan, as shown on
Exhibit 3.4.4.8, to retain buffer zones to assure that no disturbance
would cross south of that divide. A 200-foot wide buffer was
delineated between development mined areas and the hydrologic divide,
and a 760-foot wide buffer between panels to be retreat mined and the
hydrologic divide. The Division finds, therefore, that the proposed
1,765 acre permit area increase will not affect areas south of the
Minnesota Creek surface water and ground water divide. Therefore, the
subsidence findings do not require any substantive amendment as a
result of the 1,630 permit area revision.
The Division finds that the following stipulations are necessary for
finding of compliance with subsidence related requirements of Rule
2.05.6(6) and 4.20.
Stipulation No. 15
THE DIVISION DIRECTS WECC TO COMPLETE THE INSTALLATION OF THE
SUBSIDENCE MONITORING NETWORK PRIOR TO THE INITIATION OF EXTRACTION OF
COAL WITHIN THE PANEL DESIGNATED IN APPENDIX A TO THE NOVEMBER, 1984
PERMIT REVISION APPLICATION ENTITLED "APPLICATION TO REVISE