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• 2.05.6(6) <br />Monitoring has been performed during early summer and fall of each <br />year. However, future monitoring will be performed in accordance <br />with the subsidence monitoring schedule presented in Exhibit 22. <br />The results of the subsidence survey will be transmitted to the <br />Division semi - annually. All subsidence monitoring results are <br />submitted to the Division for review. The results of the <br />monitoring indicate that the surface elevation has decreased from <br />negligible amounts to about 6 -feet in the case of subsidence <br />monitoring point U21. The subsidence is "high" at this point <br />because it is located where the overburden is only 430 -feet and <br />where both the C and B -Seams were extracted. <br />The area to be mined west of the First North Mains is not covered <br />by any subsidence monitoring stations. The renewable resources in <br />Lone Pine Gulch are protected from the effects of subsidence by a <br />restricted mining area and limited extraction. This prediction <br />will be verified by monitoring three additional subsidence <br />monuments. One is located in Lone Pine Gulch near springs G -26A <br />and CR -12, and two are located on the hillside above the springs. <br />The subsidence monuments located on the hillside are at about <br />elevation 6909 and 7132. The lower monument at elevation 6909 is <br />protected from the effects of subsidence by limited extraction in <br />panel 18. The upper monument at elevation 7132 is not protected <br />from the effects of subsidence. Monitoring of the three new <br />subsidence monuments will be performed four times per year as close <br />to the end of each calendar quarter as possible. The results of <br />the subsidence survey will be transmitted to the Division semi- <br />annually. <br />Subsidence Effects on Landslides <br />A study on the potential effects that subsidence would have on <br />landslides in the area of the new mine plan at the Bear No. 3 Mine <br />resulted in a similar conclusion to that presented by RMG report. <br />The RMG report concludes that subsidence could have small effects <br />on both the existing landslides and new landslides in the area. <br />This effect is caused by tensile ground strain which will occur in <br />the rock mass above the planned undermining of the area. The <br />ground strain will create tension cracks on the surface which will <br />temporally alter the state of stress in the rock and could increase <br />• the amount of moisture present in the near - surface rock and soil <br />2.05 -61 Rev. 11 -17 -94 <br />