Laserfiche WebLink
Mr. Hal Simpson • <br /> May 19, 1995 <br /> Page 3 <br /> are not part of this plan and the remainder of the area is not irrigated, the <br /> determination of effective precipitation and net evaporation will be based on non- <br /> irrigated, natural pasture land. During the growing season the effective precipitation is <br /> 90% of total. During the non-growing season, non-frozen months, the effective <br /> precipitation is 20%. Soil moisture credit is taken to offset evaporation in the frozen <br /> months of January and February. Table 1 shows the estimated evaporation depletion <br /> on a monthly basis. <br /> After the first year, the proposed operation will mine approximately 1.6 million tons per <br /> year. Table 2 shows the monthly distribution of mined product. No water will be <br /> used for dust suppression or reclamation. The monthly distribution of evaporation loss <br /> is also shown on Table 2. <br /> The timing of depletions for the Dahlia North Resources Pit is complicated by the <br /> different mining methods and locations on a single site. The two wet mined areas are <br /> at different distances from the river. The slurry wall area is isolated from the river. <br /> The lagged depletions from Areas 1 and 2B were individually calculated using the <br /> Glover technique. The center of Area 1 is located 1000 feet from the river and the <br /> center of Area 2B is located 2000 feet from the river. Lagged depletion factors were <br /> developed for each site by assuming a pumping schedule based on the maximum <br /> amount of monthly depletions. The analysis was run for a ten year period. A monthly <br /> stream depletion multiplier (SDM) was developed by dividing the depletion in the <br /> corresponding month in the ten year by the pumping rate. <br /> The calculation of lagged depletions for Area 1 is computed based on the assumption <br /> that the area will be mined out in about 4 months and filled in within one year. Table <br /> 2 shows the depletions estimated for Area 1. Variations of depletions will be adjusted <br /> by the stream depletion multiplier. Since no depletion will occur in months 11 and 12 <br /> the amount of replacement will be based on the actual depletion, based on Glover. <br /> This amount may need to be adjusted slightly based on the mining. Assuming the <br /> mining is on schedule all the depletions will be replaced within one year. <br /> Table 2 shows the lagged depletions and the stream depletion multiplier for Area 2B <br /> after the depletions have achieved steady state in 10 years. Since the multiplier is <br /> based on a full schedule of mining the actual depletions incurred in a month can be <br /> determined throughout mining. For accounting purposes each month the consumption <br /> will be multiplied by the multiplier to determine the amount of replacement needed. A <br /> Page 9, EXHIBIT G-1 <br />