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Mr. Midve[ Bou/ay/Ms. Sarxha~m Dizisrat of Mvin'als aril Gotlo~ Septa>dn 29, 1999 Pale S r~ L Most of the Valora's hay production (150 tons/year estimated maximum, with a value of approximately $5,625) and grazing occurs on the Yoast property in upper Trout Creek and the Leonazd Yoast 1-Iay meadows on upper Sage Creek. All of the hay produced from the subject hay field (20 tons, approximately 13 percent of the total yield) is used to winter the sheep. The value of the Valora's hay production from the subject hay Geld represents approximately 9 percent of the value of their overall hay production. This figure does not take into account any value Eor sheep production from the Valora's opemtions since no information was available. The Valora's are aware of the proposed Yoast mine expansion and verbally indicated no objection to the project. Their existing hay field along Sage Creek is small in size, produces hay valued at approximately $495 annually, and represents the source of slightly less than 9 percent of the overall value of their annual hay production. The potential for adverse mining-related impacts to the Valora's existing operations from any increase in salinity in Sage Creek is minunal. As shown in Table 6.1, Summary of Projected Lnpacts ro Downstream Irriga[ed Crops on Sage Creek, the potential post-mining crop reduction to the hay Geld in Section 18 due to the maxattwn sl salinity increase in Sage Creek may be as high as 21 percent. However, this value represents a maximum projected reduction of only 2.8 percent to the total annual Valora hay crop. Published crop reduttion variables for the moderately sensitive bluegrass species are not available. Therefore, all available reported variables for moderately sensitive crops were tabulated and summarized in Table 6.2, Summary of Crop Reduction Variables for Moderately Sensitive Crop Species. The mean variable values for these available species were then utilized to calculate potential crop reductions for bluegrass in Table 6.1. TABLE 6.1. SUMMARY OF PROJECTED IMPACTS TO DOWNSTREAM IRRIGATED CROPS ON SAGE CREEK !10 Acre field in Section 18, T5N, R87WI Yield Decrease Predicted Salinity Relative Crop Reduction Conductivity Threshold Yield Rw (Percent/ Ecw Immhos/cm) Aw Immhoslcml Y 1 ercentl /percent/ Smooth Biome IBromus inermisl, Lincoln 13.2 2.9 1.3 79.4 20.6 Bluegrass 13.0 2.9 1.1 76.6 23.4 PROJECTED REDUCTION FOR 10-ACRE FIELD IN SECTION 18 FR: 21.3 PROJECTED TOTAL REDUCTION FOR ENTIRE FARMlRANCH OPERATION TR: 2.8 Notes: 8w =percent yie/d decrease per unit salinity increase ECw =Predicted specilic conductance of irrigation water Aw =Salinity threshold o/irrigation water FR =Projected crop reduction for the Valora field in Section 18 TR =Projected Iota/ crop reduction for the entire Valora farm/ranch operationlbased on the field in Section 18 producing approximate/ 13.3 percent of the hay /or the entire operation/ References: Banta (19881, /ppoliro !1992/, Maas !19861 /see Tab/e 6.2, Summary oI Crop Reduction Variables /or Moderately Sensitive Cio Species/