Part I

The proposed drilling plan addresses the minimum requirements to evaluate the potential of a hammer drill-in casing system. No coring is specifically planned; however, should time allow, at least two cores may be recovered through the established boreholes. Based on time available, one of the established holes may be deepened. Successful completion of all testing will result in at least two cased boreholes with reentry structures that may be used for future scientific exploration.

The drilling plan will proceed as follows:

Contingency Drilling Plan
In the event that there is operational time remaining after the conclusion of all hammer drill-in casing system tests, our drilling plan is to reenter one of the existing cased holes and core ahead until it is time to depart for the NERO site. If there are four or more days remaining in the operations schedule and there is no viable reentry site, our primary contingency plan is to deploy a new hard-rock guide base either near Site HDS 1 or adjacent to the existing guidebase at Hole 735B. Four days is the minimum time required to deploy the guidebase and drill, case, and cement a large diameter casing. Any residual time will be devoted to conventional rotary coring at this site.

If there is insufficient operational time to set a new guidebase, several short-term options remain as contingencies. These include milling and fishing operations in Hole 735B (+24 hr per attempt); additional logging with the formation microscanner (FMS) in the open part of Hole 735B with fresh water mud to reduce the resistivity contrast in the borehole, or depart early for operations at Ninetyeast Ridge.

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