One of the holes on the Mullaperiyar dam was plugged on Tuesday.
Eight holes had been drilled on the dam to check its strength. (Total length of the dam is 1,200 feet.)
While the Public Works Department (PWD) team plugged two holes made in the gallery area of the dam on Monday night, the third hole, drilled 650 feet from the left side of the dam, was filled with concrete mix on Tuesday.
The remaining five holes – four in the dam and one in baby dam – will be plugged in the coming days, according to PWD officials.
A technical team had transported raw material and necessary equipment to the dam site on Monday.
The plugging work was monitored by PWD Chief Engineer M. Sampath Kumar in the presence of Kerala officials.
S. Saravanan, managing director of a Tiruchengode-based firm that has taken up the task, said the work would be completed by June 20.