Laserfiche WebLink
• improvements between observed and calculated values were observed initially using <br />constant subsidence factor and angle of draw. <br />The goodness of fit, as measured by the correlation coefficient, significantly <br />improved only after varying both the subsidence factor and angle of draw with depth. <br />Figures 12 and 13 compare the calculated and measured results for the monuments over <br />the D7, D8, and D9 panels. Regression coefficient is 87%, indicating a good overall <br />linear correlation between measured and calculated values at the monitoring locations. <br />From this modeling exercise, it was apparent that (1) subsidence parameters are depth <br />dependent and (2) there are nonlinear ground movements locally. Since these nonlinear <br />effects are not included in subsidence models, we foresee no additional benefits by <br />changing model input and consider existing models prudent for estimating ground <br />movements in the Dove Gulch study area. <br />The calibrated version of the model was used to make quantitative predictions of the <br />new amount of subsidence resulting from the extraction of the Upper B Seam over the <br />Dove Gulch model area (figure 1). The similarities in geology and geometry (depth of <br />cover, face width, gateroad configuration) between the monitored area over the D Seam <br />and the neighboring project area justify the use of the back-analyzed parameters for the <br />predictive model. <br />Some uncertainty exists for predictions made with the model due to variations in <br />geology, mining history, and mining geometry, including actual mining heights. <br />To evaluate the potential impacts on surface resources, surface strains can be <br />estimated both during the course of mining (i.e., transient behavior) and after mining has <br />been completed (i.e., permanent behavior). The permanent results are presented in this <br />report. Within the Dove Gulch study area, seam thickness varies from 12 to 15.5 ft. We <br />have simulated a maximum extraction height of 12 ft for the entire block considering the <br />Maleki Technologies, Inc. Page 31 <br />