Laserfiche WebLink
S/h and 0.6 S/h respectively. For a 10 foot mining height, <br />which is the most severe case which will exist, the <br />following maximum strains are predicted, assuming a maximum <br />subsidence of 6.1 feet, for the profile which exists after <br />the completion of mining. <br />Overburden w Maximum Maximum <br />Depth(Feet) h Tensile Strain Compressive Strain <br />500 5.0 0.0073 0.0061 <br />1,000 2.5 0.0037 0.0031 <br />1,500 1.67 0.0029 0.0020 <br />2,000 1.25 0.0018 0.0015 <br />Large strains may also <br />of mining. The following <br />following total extractic <br />panel. <br />Overburden Maximum <br />• Depth(Ft.) Subsidence(Ft.) <br />(From Plate 12) <br />occur during inte <br />maximum strains <br />n from a single, <br />w Maximum <br />h Tensile <br />Strain <br />rmediate stag e_ <br />are predicted <br />900 foot wide <br />Maximum <br />Compressive <br />Strain <br />500 5.2 0.8 0.0068 0.0068 <br />1,000 2.7 0.9 0.0022 0.0096 <br />1,500 1.5 0.27 0,0007 0.0021 <br />2,000 1.0 0.20 0,0003 0.0011 <br />The observation by O'Rourke and Turner (1981) that the <br />maximum tensile strains can be approximately four times <br />larger for U.S. mining conditions (than for S°H predictions) <br />should be considered when using these values. However, their <br />quantitative data are limited to one case, so it would not <br />seem appropriate to consider t:Heir observations as being <br />necessarily accurate for the hlesaverde Formation. <br />Tilt is also sometimes used as a criterion for .damage <br />to structures. This is appropriate for tall structures, such <br />as multi-storied buildings or chimneys, and for structures <br />Sensitive to slight changes in gradient, such as sewer <br />lines. Tilt has not been used as a damage criterion for this <br />project since there are no structures sensitive to tilt <br />above the prooose:3 mining area. <br />• <br />_ 4; _ <br />