Chilime rescuers switch to rat-hole mining 20 days after Nepal's flood

Rescuers at Nepal's Chilime 22 MW hydropower station have started cutting a rat-hole heading through flood debris to reach six workers last seen in the underground powerhouse on 26 August. Bimal Khadka, deputy manager at Chilime Hydropower Company, said on 14 September that crews had already driven about 35 metres by hand after mechanical boring stalled, taking the total depth to 125 metres. They are now pumping water mixed with oil, a sign they may be close to the station.

Rat-hole mining is a narrow, manual method used in Meghalaya coal seams and, in November 2023, in the last stretch of the Silkyara-Barkot tunnel in Uttarakhand. At Silkyara the miners entered an 800-900 mm pipe and dug the final 10 to 12 metres after a US-made auger jammed at 46.8 metres. All 41 workers there were reached after 17 days. They had been able to speak to rescuers and take food through a drilled pipe. Chilime does not have that link.

Khadka said the hope is that water has left a void in the next 100 metres toward the powerhouse. If the route is open, a breakthrough could come quickly. If the heading is blocked again, the six men remain on the other side of a debris plug that machines have already failed to clear. Arnold Dix, the Australian tunnel specialist who advised at Silkyara, is involved in the Nepal searches. He has described the work as several potential rescues at once, each with a different blockage.

Company data compiled after the 26 August floods list 909 people missing at 11 hydropower sites. Earlier Indian reports put the figure near 900 across 12 projects in Rasuwa and Nuwakot, with about 500 thought to be inside tunnels. Four of those projects were under construction, seven were running, and one was in testing. Mud, boulders and collapsed lining closed sections of heading. The Nepal Army has been running searches across 19 hydropower tunnels.

A Delhi-NCR team of rat miners who worked at Silkyara, and later at the Srisailam Left Bank Canal collapse in Telangana in February 2025, asked in early September to be sent to Nepal. Anand Kansal, their Pune-based coordinator, wrote to the Indian ambassador. Firoz Qureshi said the team could leave at once. As of mid-September they were still waiting on permission from both governments. Several of those miners now dig sewer pits in Delhi for 700 to 800 rupees a day.

The contrast with Silkyara is the part that should stay in the record. There, trapped men could knock and eat. Here, twenty days on, the heading has reached 125 metres and the only encouraging sign is oil in the water. India has already approved 654 MW of power exports to Nepal for 18 hours a day through 31 December because so many plants are down. That export decision and this tunnel are the same flood. One is a grid patch. The other is still a search.