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Page 6.2 -Drill Hole Abandonment <br />Drill holes will be abandoned in their entirety upon completion of each drill hole. All drill holes <br />will be completely filled from the end of hole to the collar with abandonite, bentonite and or <br />cement grout or concrete. This will prevent movement of groundwater within the drill hole and <br />prevent the safety hazard of drilling and blasting into an open core hole in future mining <br />activities. The angles of the underground drill holes will range from +45 degrees to -90 degrees. <br />There are various types of plugs or caps used for underground core hole abandonment. For up <br />holes or holes that encounter artesian water: <br />• The drill casing can be set in resin and equipped to accept a screw on cap to seal the <br />hole. The cap has a 1 inch valve that allows abandonite and or concrete gout to be <br />pumped into the hole. <br />• Mechanical Grout Packer — Can be used with or without casing that is set in resin. A <br />grout packer is inserted into the core hole with the drill and is set in place by turning the <br />drill pipe. The grout packer is equipped with a valve that allows abandonite or concrete <br />grout to be pumped into the hole. <br />• Hand Set Packer — This is a rubber plug that is placed near the collar of the hole that <br />expands by turning a bolt to plug the hole. This packer is equipped with a valve that <br />allows abandonite or concrete grout to be pumped into the hole. <br />• A 5 to 10 foot cement plug will cap each up hole and holes that encounter artesian flow. <br />Flat or down angle holes will be abandoned with the same procedures as the surface core <br />holes. The abandonite and or concrete grout will be placed "bottom up" with a 5 to 10 foot <br />cement plug capping each hole. <br />