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• Tables 4.6.5.2-1 and 4.6.5.2-2 present maximum predicted subsidence <br />values for the various mine and overburden geometries present in No. 1 <br />Mine and No. 3 Mine, respectively. These values are based on an analy- <br />sts applying NCB data (Fig. 3. 1975) to selected mine and overburden <br />geometries characteristic of the North Thompson Creek mining operation. <br />It is believed that these calculated maximum subsidence values are ton- <br />servative and effectively define the outer envelope of possible subsid- <br />ence that may occur as a result of mining at the North Thompson Creek <br />Mines. Ysrlous researchers have indicated that NCB data produce conser- <br />vative maximum subsidence values when applied to overburden sections <br />containing the thick sandstone beds that are a characteristic of coal <br />fields in the western United States (King, 1980; Abel and Lee, 1980; <br />and. Kapp. 1974). <br />Description of Morst Possible Consequences <br />This discussion of the worst posslbte consequences of subsidence is sub- <br />divided Into two parts. The first part discusses worst posslbte subsid- <br />ence effects for both full extraction mining areas and for areas where <br />the only mining will consist of widely spaced development entries driven <br />in the coal seam. The second part discusses the worst possible conseq- <br />uences of the worst possible subsidence effects on structures and renew- <br />able resource lands 1n the permit and adfacent area. <br />• 18 <br /> <br />