Muthulakshmi, who fell into the improperly closed 900-feet borewell at Suryapalli village at around 7 am, remained stuck within a depth of about 18 feet and was pulled out by rescuers around 11 pm in an unconscious state, police said.
Daughter of farm labourers, the girl was immediately rushed to the Karur Government Hospital, about 50 km from the mishap spot, where doctors attempted in vain to revive her by administering oxygen, police said.
Doctors later declared her dead, as the efforts ended on a tragic note.
The girl had fallen into the borewell, which was closed in a crude method after it failed to yield water. It was to be properly sealed today.
The rescue operations by Fire and Rescue Service personnel and others which began at about 8 am using three earth moving equipment suffered delay due to rocky terrain.
A pit was dug adjacent to the borewell to reach the girl, stuck at a depth of about 18 feet where the diametre was around 12 inches.
The girl was administered oxygen during the rescue operations and her murmurs were heard till 5 pm after which she fell silent.
District Collector S Jayandhi and other top police and district officials oversaw the operations.