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Table T2. Leg 210 operations plan and time estimate for alternate sites.

Site Location
(lat/long)
Water depth
(mbrf)
Operations description Transit
(days)
Drilling
(days)
Logging
(days)
             
NNB-03A 45.3267°N 4553 Two casing strings (reentry cone, 20, and 16 in)      
(2 casings) 44.6317°W   with 10-3/4-in liner as contingency      
             
      Hole A: drill-in 80 m 20-in casing with reentry cone   1.8  
             
      Drill with 22-in underreamer ~80 to 500 mbsf      
      set 475 m 16-in casing, cement   4.8  
             
      RCB 500-1240 mbsf (sediment)   8.2  
      RCB 1240-1340 mbsf (basement at 1240 mbsf)   3.5  
      Log: triple combo/FMS-sonic/WST-VSP     2.2
      SUBTOTAL: 0.0 18.3 2.2
      TOTAL OPERATING DAYS (56 days available): 20.5    
             
      NNB-03A ALTERNATE OPERATIONS:      
NNB-03A   4553 Hole A: underream to 18-in ~525 to 1240 mbsf      
(3 casings)     and set 740 m 10-3/4-in liner @ 1215 mbsf, cement   5.5  
             
      Hole A: RCB basement 1240-1480 mbsf   11.8  
      Log: triple combo/FMS-sonic/WST-VSP     1.7
             
      Hole B: APC to refusal ~250 mbsf, XCB to refusal ~500 mbsf   4.7  
      Log: triple combo/FMS-sonic     1.4
             
NNB-01B 45.3917°N 4563 Three casing strings (reentry cone, 20, 16, and 13-3/8 in)      
(3 casings) 44.7583°W   with 10-3/4-in casing as contingency      
             
      Hole A: drill-in 60 m 20-in casing with reentry cone   1.8  
             
      Drill with 20-in underreamer ~60 to 800 mbsf      
      set 775 m 16-in casing, cement   6.2  
             
      RCB 800-1375 mbsf   7.7  
      Log: triple combo/FMS-sonic/WST-VSP     2.0
             
      Underream with 14-3/4-in tricone bit ~800 to 1375 mbsf      
      and set 725 m 13-3/8-in liner @ 1350 mbsf, cement   6.5  
             
      RCB sediment 1375-2180 mbsf   17.7  
      RCB basement 2180-2280 mbsf   4.3  
      Log: triple combo/FMS-sonic/WST-VSP     2.3
      SUBTOTAL: 0.0 44.2 4.3
      TOTAL OPERATING DAYS (56 days available): 48.5    
NNB-01C 45.4661°N 4412 Three casing strings (reentry cone, 20, 16, and 13-3/8 in)      
(3 casings) 44.9050°W   with 10-3/4-in casing as contingency      
             
      Hole A: drill-in 60 m 20-in casing with reentry cone   1.8  
             
      Drill with 20-in underreamer ~60 to 800 mbsf      
      set 775 m 16-in casing, cement   6.2  
             
      RCB 800-1375 mbsf   7.7  
      Log: triple combo/FMS-sonic/WST-VSP     2.0
             
      Underream with 14-3/4-in tricone bit ~800 to 1375 mbsf      
      and set 725 m 13-3/8in liner @ 1350 mbsf, cement   6.4  
             
      RCB sediment 1375-2360 mbsf   21.8  
      RCB basement 2360-2460 mbsf   4.3  
      Log: triple combo/FMS-sonic/WST-VSP     2.3
      SUBTOTAL: 0.0 48.2 4.3
      TOTAL OPERATING DAYS (56 days available): 52.5    
NNB-04A 45.1967°N 4624 Hole A: RCB 0-135 m (sediment)      
  44.3767°W   RCB 135-235 m (basement at 135 mbsf)   4.7  
      Log: triple combo/FMS-sonic/WST-VSP     1.4
      SUBTOTAL: 0.0 4.7 1.4
      TOTAL OPERATING DAYS (56 days available): 6.1    
NNB-05A 45.1967°N 4695 Hole A: APC to 250 mbsf, XCB to 355 mbsf   3.4  
             
  44.3767°W   Hole B: drill ahead 335 mbsf,      
      RCB 335 to 435 mbsf (basement at 355 mbsf)   4.9  
      Log: triple combo/FMS-sonic/WST     1.7
      SUBTOTAL: 0.0 8.3 1.7
      TOTAL OPERATING DAYS (56 days available): 10.0    
NNB-06B 45.1033°N 4727 Hole A: APC to 250 mbsf, XCB to 500 mbsf   4.6  
             
  44.1967°W   Hole B: drill ahead 490 mbsf,      
      RCB 490 to 858 mbsf (basement at 758 mbsf)   7.5  
      Log: triple combo/FMS-sonic/WST     1.8
      SUBTOTAL: 0.0 12.1 1.8
      TOTAL OPERATING DAYS (56 days available): 13.9    

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