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APPENDIX 3.4-A • A test area was chosen for its similarity to the Moffat Area in regards to known pre- and postmining information such as mining methods, topography, geology - stratigraphy and structure and coal seams mined. The mining method used on the test area closely resembles the mining methods for the Moffat Area. The pits were mined approximately parallel to The original contours and progressed in an easterly and upslope direction. The overburden material from each pit was cast downhill into the preceding pit. Both the Moffat Area and test area lie along the same ridge line as shown on Exhibit I. The original and postmining contours for The Test area are shown on Exhibits 2 and 3, respectively. A weight average factor, shown on Tables I and 2, was determined for each of the small planimeter units numbered on these two exhibits. The known totals were Then used to calculate the average original elevation and average postmining elevation for the test area. This is also shown on Tables I and 2, respectively. The geology of the area is consistent with the Moffat Area in respect to siratigraphy and structural patterns. A n overburden isopach was developed from drill hole information in the general area to show varying overburden depth (Exhibit 4). A coal isopach was not developed since the coal is known to be a consistent thickness in the area. As the mining operation progresses upslope, there is a decrease in overburden depth and therefore less material will be placed into the previous pit. To compensate for This, first the original depth to the coal seam was determined using Pit I and Area I shown on Exhibit 4. Then, Pit 2 and Area I, also shown on Exhibit 4, were used To determine the depth of the overburden that will be placed info Pit I and Area I. The weighted average depth factors for Pit I, Pit 2 and Area I can be found on Table 3. The weighted average depth of the original overburden and overburden to be placed into the test ores was calculated from the results on Table 3 and can be found on Table 4. These depths were then used in the formulas shown on Table 5 to calculate overburden and overall swell factors. The final calculations show an overburden swell factor of 31.9% and an overall swell factor of 21.4°.6. These calculations are shown on Table 5. Even though this is a small area, it is believed to be a good check of the anticipated swell factor for the Moffat Area.