2019-12-13_REVISION - M1980244 (59)

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ERC CC&V water Balance user's Manual November 2019 • Globe-Schlist Pits Area(ftZ)—Input for the area of the Globe-Schlist Pits that would result in runoff for each month of the simulation • Ironclad Pit Area (ftz)— Input for the area of the Ironclad Pit that would result in runoff for each month of the simulation • Cresson Pits Area (ftz)— Input for the area of the Cresson Pits that would result in runoff for each month of the simulation • Non-VLF Pond Demands (gpm)— Input for the water demands at the Dump 4 and Ames Ponds to be used for truck fill, dust suppression, etc. • Grassy Valley Augment(gpm)— Input for the water demands for Grassy Valley augmentation for each month of the simulation • Arequa Gulch Augment(gpm)— Input for the water demands for Arequa Gulch augmentation for each month of the simulation • Available Offsite Water(gpm)—Input for how much water will be available each month for use in augmentation and makeup purposes Results Tabs The water balance model includes six results tabs: "Climate Results", "VLF1 Results", "VLF2 Results", "Other Stochastic Results", "100-Year Results", and "10-Year Results". Each tab contains a series of result graphs for various parameters. Double-clicking on each of these graphs opens up a separate window allowing the user to view the graph in expanded detail, with results presented for the mean, maximum, minimum, 50th percentile, 5th percentile, and 951h percentile values. Figure 5 presents an example result graph taken from the model (showing leach flow rate at one of the PSSAs over the course of a simulation). Once expanded, the user can also change the graphs to a table view in the top left corner of the figures to see the results in tabular form (shown in Figure 5). Figure 6 shows a screenshot of the same result switched to a table view. A summary of the results presented in each tab is described below: • Climate Results — The "Climates Results" tab is broken up into two sections: "Precipitation Results" and "Evaporation Results". There are three graphs under "Precipitation Results", which present the monthly precipitation depth predicted at the mine site throughout the simulation and the 10- and 100-year storm depths (all in inches). The "Evaporation Results" section includes seven graphs, one showing the monthly pond evaporation depth occurring at the site(inches)and six showing the evaporative loss at each PSSA(gpm) over the course of the simulation. • VLF1 Results — The "VLF1 Results" tab presents result graphs at each PSSA for a variety of parameters, including precipitation runoff to the PSSAs, leach application rate, ore and leach absorption, leach drainage, PSSA pond volume and elevation at the end of each month, and the pumping rate modeled at each PSSA. All of these results are presented stochastically, although some of the parameters do not vary based on rainfall so do not show any variability between the different percentile results. • VLF2 Results—The "VLF2 Results" tab presents similar results as those listed for VLF1, but for the Phase 1/2 and Phase 3 facilities at VLF2. 7