Chief Minister Arvind Kejriwal met the rat-hole mining experts from Delhi who participated in the operation to rescue the 41 workers trapped in Silkyara tunnel, officials said on Friday.

The workers were trapped inside the tunnel in Uttarakhand after a portion of it collapsed. They were rescued on Tuesday following 17 days of a multi-agency operation.

The 12-member team of rat-hole mining experts were called to do the drilling after an American auger machine came across hurdles while clearing the rubble.

According to officials, some of them are involved in laying sewer lines and pipelines for the Delhi Jal Board.

"Kejriwal met the miners from Delhi. During the meeting, Water minister Atishi and Urban Development minister Saurabh Bharadwaj were also present in the meeting. The miners returned from Uttarakhand on Thursday," the official added.

Rat-hole mining involves digging of narrow tunnels, usually 3-4 feet high, for workers to enter and extract coal. The horizontal tunnels are often termed "rat holes", as each just about fits one person.

At the Silkyara tunnel, the 12 experts were called by Trenchless Engineering Services Pvt Ltd and Navayuga Engineers Pvt Ltd to deploy the rat-hole mining technique horizontally in the collapsed part of the main structure.

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