Before revision: Technique Rat-Hole Mining technique is a procedure of digging manually wherein the worker involved in extraction can hardly crawl in and out, as the tunnel is dug 3 to 4 feet in depth.
After revision: Technique Rat-Hole Mining technique is a procedure of digging manually wherein a narrow worker involved in extraction can hardly crawl in and out, as the tunnel is dug 3 to 4 feet in depth.