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<br />' Battle Mountain Gold Company <br />January 26, 1989 <br />Page 2 <br />second method derived the solution from an equation. The curve- <br />matching solution was based on a method developed by Ramey, et <br />' al (1975), and incorporated into a computer program by In-Situ, <br />Inc. The equation method used to evaluate the data were <br />developed by Bouwer and Rice (1976) for slug tests conducted in <br />' the unconfined alluvial aquifer, and by Ferris and Knowles (1962) <br />for the slug test conducted in the confined Santa Fe Formation. <br />The results of our slug test analyses for values of hydraulic <br />' conductivity are presented in Table 1 for both methods. As this <br />table shows, the general hydraulic conductivity value in the <br />Santa Fe Formation at well G-1 is estimated to be 10-7 <br />centimeters per second (cm/sec), while the hydraulic <br />conductivities in the alluvial wells (G-2 and G-3) are <br />approximately 10-4 cm/sec. <br />' Based on an approximate pit configuration and how it intersects <br />the Rito Seco alluvium/Santa Fe contact, we have estimated water <br />losses from the Rito Seco to the pit for water rights purposes. <br />' We understand that the currently-proposed south face cif the west <br />pit wall intersects an approximate 40 foot of thickness of the <br />Rito Seco alluvium, 25 feet of which is saturated. Furthermore, <br />' we understand that this contact with the Rito Seco alluvium <br />extends approximately 850 feet along the south face of the west <br />pit wall. The remainder of the south face of the went pit wall <br />contacts Santa Fe Formation. Assuming a hydraulic conductivity <br />in the Santa Fe Formation of approximately 4 x 10-7 cm/sec, a <br />hydraulic conductivity of 4 x 10-4 cm/sec in the Rito Seco <br />alluvium, a pit wall length of approximately 1,500 feet (of which <br />t 850 contacts the Rito Seco alluvium) and a hydraulic giradient of <br />0.63 foot per foot (ft/ft), we estimate the seepage through the <br />south end of the west pit wall to be 125 gallons per minute <br />' (gpm), or approximately 20o ac-ft/yr. <br />It should be noted that these slug test methods are ]oased on a <br />' variety of assumptions that are never entirely met in any field <br />situation. Therefore, these assumptions should be evaluated <br />carefully by any user of the enclosed data. <br />t If you have any questions regarding our slug test data analyses, <br />please feel free to give us a call. <br /> <br />Yours truly, <br />~` ~~~ <br />' Bruce A. Lytle <br />BAL/pa Senior Project Engineer & <br />Enclosure Associate <br />