Laserfiche WebLink
• <br />March 2000 -56- 993-2099.150 <br />A probabilistic model was used in lieu of a simple deterministic model using mean monthly <br />precipitation (and evaporation) values. The probabilistic approach was chosen because <br />precipitation and evaporation vary month by month and from year to year. This variability <br />or uncertainty in the amount of precipitation from month to month was accounted for in the <br />water balance model through the use of a variability-based software program (Crystal Ball) <br />which produces probabilistic simulations that are based upon probability distribution <br />functions. Probability distribution functions were developed using actual historic <br />climatological data, combined with more recent site climatological data from the Cresson <br />Project, and the data was assumed to conform to a gamma distribution (Sanders 1980). <br />The gamma distribution is defined by alpha and beta parameters where: <br />a =(X )' <br />a <br />• and <br />8=(6--X) <br />where: <br />X =Mean <br />a =Standard deviation <br />7.2 System Analysis <br />7 1 Cystem Inflow Evaluation <br />As identified in Section 7.1, fluid inflow to the leaching facility has three components: <br />(1) fluid applied as barren solution, (2) direct precipitation falling onto the VLF, and <br />• (3) moisture contained in the matrix of the ore as it is delivered to the VLF. During <br />I:\99\309riFINAL REPORT3099MAIN2.DOC Golder Associates <br />