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<br />COLO. TECH. CENTER <br />CONT'n <br /> <br />We had done the geologic map, and we could <br />not identify from the geologic mapping an <br />examination of the surface. I think we have <br />observed every square foot of this area. <br />We have marked, and we show on the map, some <br />areas that may be subsidence. Otherwise, <br />they are shallow impressions, maybe undrained. <br />They could be the result that the ground has <br />sunk over an old mine. We can't prove it one <br />way or the other from the surface, so, we <br />selected locations for six drill holes in <br />order to see what the conditions were in the <br />depth of the mine. We looked for several <br />things. First, if the mine mapping is accurate <br />that we could identify specific features <br />underground that are shown on the mine maps, <br />such as the pillars; we picked two of those <br />holes. Then we wanted to see, for instance <br />in this hole, this was an area which was <br />recorded totally mined out and all the <br />pillars pulled. In such a case, we would <br />expect complete collapse of the roof; and <br />we would anticipate that there might be <br />subsidence on the surface. We picked this <br />area because it was a smaller area, but there <br />were pillars on either side. We drilled this <br />one to see what the conditions of those <br />pillars were. In this area we are talking <br />about mining that was stopped in 1947 - 1952, <br />which is relatively recent. We came over <br />and put two holes, one in a totally mined <br />out area in the old Nonporeal Mine, which <br />was closed in 1925, which is very old. We <br />did drill a hole that would drill a pillar <br />in this very old mine. We wanted to see <br />what the condition of this pillar was. Whether <br />it was still holding or whether if failed, <br />and so we selected a hole there. Then, we <br />came down into the Centennial Mine and drilled <br />a pillar in that area, to see what the con- <br />dition of that pillar was. I could go into <br />considerable detail, but I will just sum- <br />marize. <br />We have completed all but about 30 feet of <br />this hole. We have drilled five 9/l0ths holes <br />since we had this last meeting. So, we <br />know what we have done in all of these. <br />This one still has probably 30 or 40 feet <br />to go and we couldn't get into the fields <br />last week because of rain. <br />The standard procedure for this, as we have <br />learned, we use a rotary bit, we drill like <br />you drill water wells and get cuttings down <br />to about 40 feet above the mine opening. <br /> <br />-9- <br />