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999 <br /> I <br /> � nn /Gf �J 2,7 <br /> JOHN F. ABEL, JR. ,r`- f / 7 / ^ ✓ 4 9 310 LOOKOUT VIEW COURT <br /> MINING ENGINEER GOLDEN,CO 80401 <br /> 303-27"W l <br /> !{ FAX 278-8163 <br /> JFAbe12@Flome cm <br /> August 17, 2000 <br /> Mr. Larry Perino Received <br /> �Sunnyside Gold Corp. <br /> " P.O. Box 177 XW 2 5 2000 <br /> Silverton, CO 81433 <br /> psPurango Field Office Dear Larry: ion of Minerals 8 G <br /> eologj, <br /> This is the letter report you requested for the design of the <br /> near portal Terry Tunnel bulkhead. A 7-ft thick bulkhead is <br /> recommended for installation in the dry solid latite section of <br /> the Terry Tunnel between stations 3+05 and 3+12 from the portal at <br /> a depth of 200 feet, as indicated on Figure 1 . The purposes of <br /> this bulkhead are to: <br /> 1) impound as much of the estimated 50 to 60 gpm of water <br /> entering the Terry Tunnel downstream from the existing <br /> bulkhead, <br /> 2) recharge water back into the water producing fractures <br /> intersecting the tunnel, partially returning the water <br /> table to the its original level before the Terry Tunnel <br /> was driven and <br /> 3) reduce the oxidation rate for sulfide minerals which will <br /> be deprived of the essential oxygen being carried by the <br /> surface water currently descending to the tunnel along the <br /> fractures carrying water from the near surface fracture <br /> zone to the tunnel. <br /> The 66 water inflow, wet and damp locations in the Terry <br /> Tunnel observed during our inspection of the Terry Tunnel on <br /> August 11, 2000 are listed on Table 1 . The water producing <br /> locations are between the Benjamin Franklin vein laterals at <br /> survey station T-9, 15+54, and the portal, shown on Figure 2 . The <br /> largest volume of water inflow, approximately 10 gpm, is from the <br /> Benjamin Franklin vein laterals indicating the high permeability <br /> of that vein structure. There are three additional major, greater <br /> than approximately 3 gpm, water inflow locations in this section <br /> of the Terry Tunnel . Obviously, the higher inflow locations are <br /> being actively recharged from surface water through the fracture <br /> permeability of the latite formation. <br />