Laserfiche WebLink
<br />• Tables 4,5 and 6 present the calculated cmaxd•~~++~nawer soundatd~o .d~ <br />placements <br />~Y for the ,o~gwa~Ifl~and:~+r;oom'~andwjp'•il~.tl~Ya!"mitnYi~ng~p~IanSt <br />~ Since minixyg <br />takes place progressively a tower over multiple longwall panels under virgin <br />ground may be subjected temporarily to the "worst-case" conditions under tensile <br />stain, i.e. the diagonal may initially extend 0.20 ft, and then under compressive <br />strain the diagonal may shorten 0.16 ft inside its initial position, and may <br />eventually even return to its original position. The deformation of the <br />tower footings may stop anywhere along this deformation path. This results <br />from the fact that a tower may be positioned anywhere above a longwall panel. <br />The optimum design for the towers would be for them to tolerate the maxi- <br />mum compressive strain, shortening the diagonal 0.23 ft over a single longwall <br />• panel, the maximum tensile strain, extending the diagonal 0.20 ft when the <br />second panel is mined, and the maximum tilt of 51 minutes. <br />Figure 10 and Table 7 present NCB structure (building) damage prediction <br />with respect to mining induced surface strains. A 57-ft structure could <br />tolerate about 4000,4£ and suffer only "slight" damage. Unfortunately, the <br />available literature provides no guidance for power transmission lines. <br />Tables 8, 9, and 10 present tabular estimates of subsidence damage predictions <br />by various authors for various surface structures, but not power transmission <br />lines. <br />ROADSIDE MINE SUBSIDENCE EXPERIENCE <br />The monitored and observed subsidence experience at Roadside Mine has <br />• been at depths less than 1200 ft. The mining heights have been about six <br />t. <br />