The depth of this shaft and its location in the courtyard is very suggestive of one of 18th dynasty date. Back in 1903, Robert Mond excavated in this courtyard and left a sketch plan of two shafts (shown here).
These can, in fact, be tied in with the plans which were produced after the excavation was finished.
What is remarkable, if this is the same shaft, is the amount of subsequent floors and constructions which were put over the shaft between its investigation in 1903 and the eviction of the tomb inhabitants in 1909.
Plan from ASAE 6 (1905), 87 fig. 22.