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to remediate. Proper consideration of the technical setting before <br /> initiating inappropriate decommissioning activities should provide <br /> for preventing such occurrences. <br /> Miscellaneous Criteria <br /> Regardless of the type of well or borehole to be decommissioned, <br /> specific recipes of grout should be established for anticipated <br /> conditions and not changed unless new conditions warrant. In <br /> addition, the volume of grout needed for decommissioning should be <br /> calculated and always compared with the amount actually used. <br /> Injection pressures needed to achieve effective seals should be <br /> calculated using specific gravity of the sealant and hydrostatic <br /> head of the grout column above the packered off zone. Usually, <br /> injection pressure should be as low as possible to prevent <br /> hydrofracturing natural geologic seals. Pressures that induce <br /> hydrofracturing complicate the decommissioning activity and provide <br /> for injecting excessive amounts of grout. The duration that <br /> injection pressures are maintained and any other conditions that <br /> arise during the process should be rigorously monitored. All <br /> decommissioning activities specified in approved workplans should <br /> followed as much as possible. Major deviations from technical <br /> specifications presented in the workplan should only be performed <br /> upon obtaining formal approval from individuals in charge of the <br /> project. All activities should be fully and accurately documented <br /> in a field log book. <br /> 6 <br />