_INSPECTION - C1981010 (44) - Laserfiche WebLink

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October 24,2013 C-1981-010/Trapper Mine JLE measured at each sample point is generally consistent throughout the site. A surveyed elevation point is located near the water tanks adjacent to the mine office. The elevation at this point is measured with the GPS and the difference of that measurement from the know elevation is used as a correction factor. During this inspection the correction factor was 56.2 feet,meaning 56.2 feet was added to each of the GPS measured elevations found at each sample point. Using Microsoft Excel®,the Division can chart the PMT map elevations, SL15 map elevations and the measured elevations to create cross-sections from the transects for each reclamation parcel for an easy comparison. During this inspection the Division walked 8 transects;maps are enclosed with this report that depict the location of each of these transects and the elevation sample points. Attachment A of this report is a summary table of the elevation data collected out in the field and the elevations interpolated at each sample point from the maps discussed above. Attachment A also contains the cross-section created from each transect. Below is a discussion of these results. For all of the elevation sample points measured out in the field,the elevations measured with the GPS unit were on average 16.5 feet higher than the elevations interpolated from the PMT map and 14.4 feet higher than the elevations interpolated from the SL15 bond release maps. Parcel A-B-13 was observed during the inspection. Several rills have begun to form on the eastern side of the parcel that should be monitored. Overall this parcel has a north eastern aspect and blends in well with the adjacent Phase III release area and adjacent graded areas. Large slumps or slides were not observed. Transects 1 and 2 fell within this parcel. For Transect 1,based on the elevation samples points,the elevations interpolated from the SL15 map were on average 1.6 feet lower than the approved post mine topography elevations interpolated from the PMT map. The measured elevations appeared to be on average 20.9 feet higher than the elevations interpolated from PMT map. The cross-section derived from the SL15 map elevations and the PMT map elevations are nearly indistinguishable. Transect 2 measured 4 sample points within this parcel. The elevations interpolated from these sample points from the SL15 map and the PMT map are almost the exact same. The measured elevations points were on average 9.21 feet higher than the approved post mine topography. All of the cross-section lines from Transect 2 are similar in grade and slope. Sample point B of transect 1 appears higher than the elevations derived from the PMT map and the SL15 map. The Division may need to re-sample this transect and or re-evaluate this portion of the parcel. Parcel Z-A-13 was evaluated with Transects 3,4, 5 and 6. This is a large undulating parcel with varying aspects and slopes. Several larger rills and gullies were observed along the transects. The Division marked the general location of the features using the GPS unit and they are depicted on the enclosed maps. Large slumps and slope failures were not observed. Transect 3 is located on the western end of the parcel. On average,the elevations interpolated at the sample points along this transect from the SL15 map were about.5 feet higher than the elevations interpolated from the PMT map. The measured elevation at the sample points along this transect was about 21 feet higher on average than the elevations interpolated from the SL15 map and the PMT map. Transect 4 is also on the western portion of this parcel. The difference in the elevations interpolated from the SL 15 map and the PMT map at the sample points along this transect are negligible. The measured elevations were on average about 10 feet higher than the elevations interpolated from the SL15 and PMT map. Transect 5 is on the eastern Number of Partial Inspection this Fiscal Year: 3 Number of Complete Inspections this Fiscal Year: 1 Page 3 of 8