|
Calculation Brief
<br />Evaluation of the Sensitivity of Percolation Estimates through
<br />Mine Rock Stockpiles on the Simulated Precipitation Rate
<br />describes a sensitivity evaluation of the UNSAT-H model completed for the Van 4
<br />Mine to the hourly rate of precipitation. This calculation evaluated simulated
<br />precipitation rates (HPR values) ranging from 0.1 centimeter (cm) per hour to 4 cm
<br />per hour.
<br />2.0 Procedure
<br />¦ Estimate physical and hydrological characteristics of development rock using site
<br />specific sampling and laboratory analyses.
<br />¦ Compile climate data from locations as close as possible to the site.
<br />¦ Estimate percolation through development rock areas using UNSAT-H.
<br />¦ Conduct a series of model runs using varying values for HPR to evaluate the effect
<br />that the precipitation rate has on estimated annual percolation.
<br />3.0 References/Data Sources
<br />Advanced Terra Testing (ATT), 2009, Laboratory data for soil water characteristic curve,
<br />saturated hydraulic conductivity, grain size analyses, and moisture content. These data were
<br />developed from samples collected at the Topaz Mine in August, 2009.
<br />• Benson, C., 2006, An Introduction to Water Balance Modeling, in: Benson, C., Albright, B.,
<br />Rock, S., Valceschini, R., Waugh, J., Alternative Covers for Landfills, Waste
<br />Repositories, and Mine Wastes Workshop, November.
<br />CDM, 2009, Environmental Geochemistry Investigation of Soil and Rock Materials, Van 4
<br />Mine, prepared for Denison Mines (USA) Corp, April
<br />Colorado Division of Reclamation and Mine Safety (DRMS), 2009, Comments received
<br />from the Colorado Division of Reclamation and Mine Safety on the Environmental Protection
<br />Plan for the Denison USA Corp. Van 4 Mine, May 29, 2009.
<br />Fayer, M.J., 2000, UNSAT-H Version 3.0: Unsaturated Soil Water and Heat Flow Model
<br />Theory, User Manual, and Examples.
<br />Ford, R.C., Pierce, S.A., Ankeny, M.D., Kelsey, J., 2000, Evaluation and Management of
<br />Acid Drainage Risk from Spent Ore, El Abra Mine, Chile, in Semi-Arid Mine Waste Issues,
<br />ICARD 2000-Proceedings from the 5th International Conference on Acid Mine
<br />Drainage.
<br />CLIMATEDATA, 2008, Climate data from Uravan, Montrose, and Grand Junction Colorado
<br />weather stations, Volume 19.0, NCDC Summary of the Day-West 1, Hydrosphere Data
<br />Products, 2008
<br />•
<br />F?
<br />2
<br />C:\Nelson_Work\Denlson\UNSAT_H\HPR sensithAtyWan 4 HPR Sensitivity talc brief.doc
|