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• Subsidence Monitoring -3- November 1994 <br />elevation of this station will probably decrease a measurable <br />amount. However, there are no structures or renewable resource <br />lands within the area of influence of station U1. Therefore, <br />monitoring of subsidence station U1 will be suspended. <br />Station U2 <br />Change in elevation July 1986 - July 1994 -0.72 feet. The <br />influence area for monitoring station U2 lies above the main <br />entries, panel 1 and unmined panel 12. The graph of station U2 <br />shows a relatively constant decrease in elevation. Within the area <br />of influence panel 1 was mined last in March 1990 and the main <br />entries were mined last in January 1992. The influence area of <br />station U2 is no longer over any active mining areas. If and when <br />the main entries are pillared and panel 20 is mined, the elevation <br />of this station will probably decrease a measurable amount. <br />However, there are no structures or renewable resource lands within <br />the area of influence of station U2. Therefore, monitoring of <br />subsidence station U2 will be suspended. <br />• Station U3 <br />Change in elevation July 1986 - July 1994 -0.34 feet. The <br />influence area for monitoring station U3 lies above the main <br />entries, panel 8 and unmined panel 20. The graph of station U3 <br />shows a relatively constant decrease in elevation. The area of <br />influence was mined last in April 1993. The influence area of <br />station U3 is not over any active mining areas. If and when the <br />main entries are pillared and panel 12 is mined, the elevation of <br />this station will probably decrease a measurable amount. However, <br />there are no structures or renewable resource lands within the area <br />of influence of station U3. Therefore, monitoring of subsidence <br />station U3 will be suspended. <br />Station U4 <br />Change in elevation July 1986 - July 1994 -2.96 feet. The <br />influence area for monitoring station U4 lies above the first west <br />mains and panels 8, 9 & 10. The graph of station U4 shows a <br />noticeable dip after the pillars were extracted from the panels. <br />• The area was mined last in March 1993. The influence area of <br />station U4 is no longer over any active mining areas. There are no <br />