2015-02-18_INSPECTION - C1981028

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February 5, 2015 C- 1981 - 028 /Keenesburg Strip Mine JLE The bond release areas encompass a portion of B -Pit. The surrounding topography is relatively flat with very small rolling hills and drainages. The reclaimed area blends in well with the surrounding topography and has been backfilled and graded to create a very small hill with gentle slopes. The top of the hill is near the center of the bond release parcels. Runoff from the parcels drain to the east and west. The area is very sandy and water tends to percolate into the soil, however any water will runoff as sheet flow on the eastern side of the reclamation parcels. On the western side of the bond release parcels water runs off into a small drainage that transports the water north. In accordance with the "Guideline Regarding Selected Coal Mine Bond Release Issues," dated April 18, 1995 the Division evaluates the following items during a Phase I bond release inspection to determine compliance with Rule 3.03.1(2)(a). 1. Hillslope and drainage channel gradient and general design compliance. 2. Performance of the reconstructed topography. Symptoms of failures or instabilities such as slumping or exposed highwalls will be examined. 3. Hillslope design /function with regards to erosion. 4. Swales and depressions with regard to number of such features and effect on the post mine land use. 5. Blending of regraded land to undisturbed areas. 6. The functioning of drainages with regard to knickpoints, blending at disturbance boundaries and channel erosion. 7. Erosional Features. 8. Drainage control for the reclaimed area. In order to evaluate item #1 listed above, the Division creates cross sections of the reclaimed parcels and drainage features. For each reclaimed parcel, I walked a transect and collected GPS points every 18 paces along the transect. At each point, the location of the point is recorded and the elevation using a Trimble YUMA GPS unit. Starting at area 32, an east to west transect was walked. For area 31, a west to east transect was walked. For area 30, an east to west transect was walked. A south to north transect was walked along the west drainage and four points were collected every 36 paces along this transect. Also, there are a number of points at the site where the elevation of those points have been surveyed. I collected GPS points at three of these points known as 1 -W, 2 -W and the AMW -1 well. The location of each of the GPS points collected in the field are depicted on the enclosed inspection maps (Sheet 1 and 2). I was able to Georeference the Q -1 map depicting the approved post mine topography and the SL7 bond release Figure 2 Map that depicts the actual topography. At each of the GPS points collected, the Division recorded the elevations measured in the field, the approved elevations interpolated from the Q -1 map and the actual elevations interpolated from the SL7; Figure 2 bond release map. When using a GPS unit to measure elevation, there is a general error in the elevations collected. This error is generally consistent throughout a site. To address this issue, I calculated a correction factor. At each of the three known survey points, the Division collected a GPS point and found the difference in elevation measured in the field versus the known elevation. The average difference between what the known elevations to the measured elevation for these three points was .77208 feet. For each of the GPS points collected along each of the transects, the correction factor of .77208 feet was added to the measured elevations. Attachment 1 of this report, provides summary tables of this data and cross sections that depict the approved post mine topography, the actual topography based on the SL7, Number of Partial Inspection this Fiscal Year: 5 Number of Complete Inspections this Fiscal Year: 2 Page 3 of 9