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Mogul Mine Bulkhead Certification Report Page 4 Bulkhead pours. The concrete pump was set up downstream of the bulkhead form and outside of the portal to accommodate concrete trucks; and, concrete was pumped approximately 300' to fill the bulkhead form. The concrete was hauled to mine site from the portable batch plant with a travel time of less than 1 hour. Delay set was added at the batch plant and again after trucks arrived at the portal. A set of concrete test cylinders was taken for approximately every 6 cu. yds. placed in the bulkhead form. The test cylinders were cured on-site. Break test;; were performed at 7 days and 28 days to verify that the 3000 psi design strength was-met or exceeded. The average 7 day strength obtained from the break tests was 5467 psi and the average 28 day strength obtained from the break tests was 7325 psi, well in excess of the required 3000 psi. A1128 day samples exceeded the 3000 psi compressive strength required by design, therefore no additional testing was planned or done. The test reports are attached. Low pressure groutinu of the concrete-rock contact After construction of the air-side bulkhead form and placement of rebaz, the form was mazked for drillhole collars by nailing faucet washers to the form. at the selected locations. One ring consisting of nine holes was drilled to intersect the rock contact along the perimeter at approximately the mid-point or center of the bulkhead. The target points were selected and then appropriate corresponding collaz points were selected such that the hole could physically be drilled without hitting the rebaz:mat. Angles and distances were measured so the selected lines could be reproduced after the bulkhead form was stripped. The bulkhead was drilled and the contact was low pressure grout<;d on September 1, 2, 3 and 4. Each hole was pressured to 200+ psi and grout ptunped urdil very little grout take occurred. The pressure applied to the formed bulkhead appeazs to have been adequate to fill the contact fractures. The valve was closed on September 4th to stop the water and allow pressure to start building on the bulkhead to determine if additional grouting might be required. Initial indications were that no pressure grouting was required. Only minor seepage has been observed from fractures downstream of the bulkhead.