2007-12-17_REPORT - M1977004 - Laserfiche WebLink

Home Browse Search

Homestake Pitch Reclamation Project 2007 Geotechnical Observations Indian Creek and Tie Camp Creek Waste Rock Dumps 1. Indian Creek Waste Rock Dump a) . "10800" Level Site Description: Identical to that of past reports for 1996 through 2006. 2007 Observations: The 2007 observations are similar to those reported for this area __ during the past ten years. Visual inspection of the area has_ revealed no evidence of settling _ __ or slumping of ~tfie rock dump material in 2007. Drainage channels are functioning as designed. b) "10780 - 10650" Level Site Description: Identical to that of past reports for 1996 through 2006. 2007 Observations: The 2007 observations are similar to past observations. Visual inspection of the area has revealed no evidence of settling or slumping of the dump material in 2007. Drainage channels are functioning as designed. c) "10650 - 10600" Level Site Description: Identical to that of past reports for 1996 through 2006. 2007 Observations: In October 2001, an obstruction was removed from Piezometer IC10600, allowing it to be used for the collection of piezometric surface data. In June of 2005, a level fluctuation of 9.0 feet was observed in this piezometer, which was the greatest fluctuation to date in water elevation since the obstruction was removed. In 2006, the water level fluctuation fell back to 1.5 feet. In May 2007, the water level fluctuation once again rose by 9.4 feet and dropped back to its normal range by mid-August. The water level average in Piezometer IC10600 was 251.2 feet below ground surface (bgs), and was consistent with the readings from previous years. This condition is similar to other piezometers in the Indian Creek dump, and deemed as acceptable seasonal variation. The water level increases in 2005 and 2007 were likely a result of very wet spring conditions. "10725 - 10525" Level Site Description: Identical to that of past reports for 1996 through 2006. The minor overlap between this level and other bench designations reflects the original bench configuration. 2007 Observations: Piezometers IC10600 and IC10525 bound this area. The water level in Piezometer IC10525 increased by 9.1 feet in May 2007 and, similar to Piezometer IC10600, dropped back to normal levels in August. This behavior is very similar to that of past reports for 1996 through 2006. The seasonal maximum water level fluctuation observed in IC10525 was 9.1 feet and a water level average through the year of 229.1 feet bgs, in a total dump thickness of approximately 229 feet. "10600 - 10400" Level Site Description: Identical to that of past reports for 1996 through 2006.