Rat Hole Mining: What is Rat Hole Mining, how is digging done?

nationaldesk:
Uttarkashi Tunnel Rescue: Efforts are on to save the workers trapped inside the Silkyara Tunnel in Uttarkashi for the last 16 days.  According to the latest information, the excavation work has been completed and the pipe has passed through the tunnel.  Some NDRF and SDRF personnel have gone inside, some part of the pipe has become sharp and is being rectified.  According to media reports, drilling was done using 'rat hole mining' technique to reach the workers.
Officials said that 12 'rat hole mining' experts were deployed to make a path by digging in the remaining 10 meters of debris in the blocked part of the tunnel under construction on the Chardham Yatra route in Uttarkashi district of Uttarakhand.  Earlier, horizontal drilling was being done in the tunnel with a heavy and powerful American auger machine weighing 25 tonnes, but on Friday, the work was disrupted due to many of its parts getting stuck in the debris.  But before that he had drilled 47 meters inside the debris.
Rat hole mining is a controversial and dangerous process.  It is a method of extracting coal by digging very small pits (not more than 4 feet wide).  Once the miners reach the coal limit, tunnels are made in the side to extract the coal.  The extracted coal is dumped nearby and later transported.
 In rat-hole mining, workers use hand-held tools (chisels and hammers) to dig and scoop up the debris.  This is the most common method of mining in Meghalaya, where the coal layer is very thin.  Due to the small size of the tunnels, even minor teenagers or children are put into it.  Many children even pretend to be adults to get work in such mines.
 Several accidents in Meghalaya have resulted in the deaths of rat-hole miners.  On December 13, 2018, 15 workers, who were extracting coal through 'rat hole mining', died due to water logging in a coal mine in Kasan.