Laserfiche WebLink
Mr. Andy Rodriguez <br />November 4, 2009 <br />Depletions <br />Page 6 <br />The depletions resulting from evaporation, water lost in product, dust control and concrete batching <br />are shown in Table B below: <br />TABLE B - DEPLETIONS <br /> Water <br /> Evaporation Product Consumed in Dust Total New <br />Site Name Losses Moisture Loss Concrete Control (ac-ft) Permit <br /> (ac-ft) (ac-ft) Batching (ac-ft) Required? <br /> (ac-ft) <br />Firestein/Tigges/ <br />82.47 <br />0.00 8'64 <br />(70,380 cubic <br />1.66 <br />92.77 <br />No <br />Roberts Pit <br /> ards) <br /> 8.64 <br />La Poudre Pit 71.06 0.00 (70,380 cubic 1.66 81.36 No <br /> ards <br />North La Poudre 26.87 0.00 0 0 26.87 Yes <br />Pit <br />Total 180.40 0.00 17.28 3.32 201 <br />The Firestein/Tigges/Roberts Aggregate Mine is comprised of three adjacent properties; the <br />Firestein, Tigges and Roberts parcels. Based on the information provided, the exposed water surface <br />area at the Firestein/Tigges/Roberts site totals 34.46 acres, which includes 1.46 acres of dewatering <br />trenches in the Firestein Pit and 1.77 acres of dewatering trenches in the Tigges Pit. All pits under active <br />mining are dewatered into the Cache La Poudre River. Mining of the Roberts Pit was completed in May <br />2006 and the pit has been reclaimed and a plan for augmentation was approved in case no. <br />2002CW331. Firestein/Tigges will not be actively mined in 2009 however the mining production is <br />anticipated to restart in 2010. <br />Based on the information provided, there are 29.70 acres of groundwater exposed at the La <br />Poudre site and 11.23 acres at the North La Poudre site. Dewatering operations at the La Poudre and <br />North La Poudre sites ceased in 2003. The timing of the lagged depletions from the dewatering <br />operations was determined through a stream depletion model for these two sites. Lagged depletions <br />dues to evaporation and operational losses at the three sites were estimated using the AWAS stream <br />depletion model. <br />The Firestein/Tigges/Roberts site has been continuously dewatered since 2002. Dewatering of <br />the Roberts Pit has stopped. Dewatering of the Tigges Pit commenced in June 2005. The dewatering <br />rate at the Firestein/Tigges/Roberts site is 250 gallons per minute. The timing of the lagged depletions <br />from the dewatering operations was determined through a stream depletion model for the <br />Firestein/Tigges/Roberts site. The model addresses the lagged depletions at the La Poudre and North <br />La Poudre sites by accounting for the net accretion credits at the river that occur due to the dewatering <br />operation at the Firestein/Tigges/Roberts site. These accretions are applied to this plan against <br />depletions from the La Poudre and North La Poudre sites. The attached Table 5 shows a summary of <br />monthly depletions from dewatering.