Laserfiche WebLink
• <br />- Material will be compacted to a minimum dry density of 90% of the <br />maximum dry density of the material. <br />- Quarterly inspections for stability by a registered professional engineer <br />will be completed throughout construction. A copy of the inspection <br />reports will be retained at the mine office and a copy will be forwarded to <br />the Division. <br />• <br />The use of CRDA-1 was suspended in 1988 due to stability questions relating <br />to higher than anticipated water levels on piezometer CRDA-01. Additional <br />stability analysis was conducted in the spring of 1994 to answer this question. <br />Western Engineers of Grand Junction, Colorado did pump testing on existing <br />piezometers and installed 30 additional piezometers to evaluate phreatic <br />surfaces and pore pressures. The results of the study showed a complicated <br />series of isolated and interconnected permeable zones, some of which carried <br />water. The end results, using information gathered in the research, showed the <br />pile to be stable as designed. They defined critical water levels in the 30 <br />piezometers which would be grounds for reevaluation of the stability. <br />Monitoring of piezometers is discussed in Tab Section 18 of this application. <br />The use of CRDA-1 resumed in 1994. In the event that water level <br />measurements on the 30 piezometers indicated that any have reached the <br />Critical Target Depth listed on Table 18-4, the stability of the pile will be <br />reevaluated and corrective action taken if necessary. <br />Sediment control calculations are given for CRDA-1, 2 and 3 in Appendix 13-2. <br />Collection ditches installed during the construction of the pile may not be in their <br />final location. Temporary and permanent collection ditches will be equipped <br />with energy dissipators and/or riprap as necessary to insure stability. <br />. 13-22 (Rev. 12/16/96) <br />