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<br />COLO. TECH. CENTER <br />CONT'D <br /> <br />between that mine and the very surface of <br />the ground. If you had subsidence, I might <br />mention that we are presently involved in <br />a project in Wyoming where we have sub- <br />sidence where the mine is at a depth of <br />1600 feet. It is a Trona mine, they are <br />mining about 7 to 9 feet of trona and we <br />get a 1 to 5 feet of subsidence at the <br />service over that mine, and we know that <br />this is going to occur and why. It is <br />designed as part of the mining process. <br />We are mining right under a major plant <br />which is worth about 4 or 5 million dollars <br />and that whole plant is going to settle <br />under control conditions with no damage <br />done. <br />These mines here were mined before we <br />had that knowledge and people didn't have <br />that care. <br />But, if we look, just as in Wyoming, we <br />cored that rock if we look at that core, <br />if there is subsidence we see that all <br />through the rock. You see the fact that <br />the rock has been bent, that it has failed. <br />In all of these holes that we drilled, the <br />maximum evidence we have found of any <br />failure in the roof over a mine of 74 feet. <br />For the rest of this whole distance, <br />this is what the numbers amount to here, <br />97% etc., no evidence of any problem or <br />displacement. <br />Here where we show in black is actually <br />where we drilled in coal in order to test <br />pillars. <br />Let me pullout another map. <br />I know most of you people are familiar with <br />Coal mines, but when we appeared before the <br />LUC, the CGS was not sure about how much <br />they knew, so we prepared some simple <br />illustrations to help them understand. <br /> <br />This one simply, well we are talking about <br />the surface. We have a coal seam someway <br />down in depth which is being rotted out. <br />They mined it out left a void in here. <br />There is a load; the load that was carried <br />by the coal in here now has to be carried <br />by the pillars or the rock adjacent that <br />you have in line; otherwise that coal was <br />supporting the rock load above. When you <br />take it out something else has to support <br />it. You may put in timbers leave pillars <br />and in mining business it is fairly well <br /> <br />9. <br />