2011-12-06_REPORT - P2009025 (2)

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Therefore... Volume of VWP Cement required Cement height = 550 ft [ -] 0 ft = 550 ft Volume to be Cemented = Pi * (0.15833 ft) * 550 ft Volume to be Cemented = 43.3 ft Number of Portland Cement Bags = Volume to be Cemented / 4.7 ft3 mixed cement Number of Portland Cement Bags = 43.3 / 4.7 Number of Bags = 9.2 = 9 x 100 Ibs bags of cement with 225 Ibs of Bentonite Volume Abandonment Cement required Cement height = 668 ft [ -] 550 ft = 118 ft Volume to be Cemented = n * (0.15833 ft) * 118 ft Volume to be Cemented = 9.3 ft Number of Portland Cement Bags = Volume to be Cemented / 1.4 ft mixed cement Number of Portland Cement Bags = 9.3 / 1.4 Number of Bags = 6.6 = 7 100 Ibs bags of cement with 35 Ibs of Bentonite Process In holes where VWPs are installed a one and one quarter -inch "sacrificial" steel pipe is lowered to the bottom of the hole through the drill rod. During the lowering process, the VWP instruments are secured to the sacrificial pipe according to their assigned depths. Once the sacrificial pipe is sitting on the bottom of the drill hole, the drill rod is removed from the hole and the cementing process begins. Because the hole is imperfect and the rock poorly consolidated, the calculated volume of VWP mixture is not adequate to fill the volume of the drill hole. Calculated volumes of VWP mixture are doubled and the injection starts from the surface and is pumped down through the sacrificial pipe, continuing until all the mixed VWP cement is injected. The doubled cement volume ensures that the VWP mixture is observed returning to the surface, flowing out of the drill hole on the outside of the sacrificial pipe, therefore the entire hole and VWPs are fully cemented. Once the VWP mixture is completely injected and there is return of the injected cement at surface, the calculated abandonment cement mix is injected. Because the abandonment grout mix is injected last, and because the sacrificial pipe is still sitting on the bottom of the hole, the lowest portion of the hole is filled with thicker abandonment cement, and the upper instrumented portion of the hole is filled with VWP cement. The sacrificial steel pipe stays cemented in place. All non -VWP holes are abandoned entirely with the abandonment mixture from the bottom to the top of the hole. The drillers lowered a one -inch pipe to the bottom of the hole and start pumping the Abandonment Cement. As they pumped the cement mixture they continually pull out the grouting pipe until the hole is completely filled with the abandonment cement and the one inch pipe was out of the ground. 110 N. Rubey Drive Suite 201, Golden Colorado, 80403 PO Box 18041, Golden Colorado, 80402 Ph: (303) 279 4946 Fax: (303) 279 4934 www.blackrangeminerals.com