GENERAL44693

• Permit No: C1981020
• IBM Index Class Name: General Documents
• Doc Date: 4/2/1998
• Doc Name: PROPOSED DECISION & FINDINGS OF COMPLIANCE FOR RN3
• Permit Index Doc Type: FINDINGS
• Media Type: D
• Archive: No

Station 72+70' through 75+50'
Station 82+25' through 83+60'
Station 85+75' through 87+25'
Station 88+40' through 95+00'
Station 95+00' through 101+00'
Station 101-00' through 104+30'
The geological mapping included within Exhibit O and the report prepared by Geo-Hydro
Consultants, Inc. indicated that each of the above-listed cut slopes will be excavated in
materials which were mapped on unconsolidated soils. (See geo-technical map, sheets 1,
2 and three, Exhibit 0 of the application.) The applicant proposes to excavate these soils
to finish slopes of roughly ]h:lv. Slope heights will reach 135 feet. Slopes which
exceed 60 feet in vertical height aze designed with a 15-foot-wide intermediate terrace
bench, which will result in overall slope gradients between l.lh:ly and ].2h:ly for the
affected cut slopes.
Pursuant to Rule 4.03.1(3)(c)(I) and in response to Division comment, the applicant
completed a mathematical stability analysis, based upon appropriate material strength
data, to determine the static slope safety factor of the designed cuts. The analysis
considered worst-case situations characteristic of the materials and cut slope
configurations proposed within the plan. Alternatively, the applicant chose to
demonstrate, through appropriate geo-technical analysis, that a safety factor of less than
1.5 would not result in significant environmental harm or harm to the public health and
safety.
The supplemental stability analysis of the haul road cut slopes considered the relative
stability of ttie various cut slopes prior to disturbance, in their present pioneer road
configuration, as reconstructed, and as reclaimed. In response to preliminary results of
this analysis, the application made several design and reclaimed configuration
amendments.. In all cases, the amended designs achieve final reclaimed configurations
which achieve static slope safety factors in excess of the original undisturbed slopes. Due
to this improvement in construction, the haul road will not result in significant
environmental harm or harm to the public health and safety. However, because the static
slope safety factor of the affected azeas is below the normally desired for road cut slopes,
the Division imposed the following stipulation upon the permit during Permit Revision
No. 1 approval:
Stipulation 1`Io. l5
THE DIVISION DIRECTS GRAND VALLEY COAL COMPANY TO INSTALL
SIGNS AT 7'HE PERMIT BOUNDARY AND AT STATION 67+00' ADJOINING THE
HAUL ROAD. THESE SIGNS, LEGIBLE FROM THE HAUL ROAD WHILE
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