longwall face वाक्य
"longwall face" हिंदी में longwall face in a sentenceउदाहरण वाक्य
- Three longwall faces in the 3 ft thick seam were commenced, but the ensuing recession appears to have made it uneconomic and production ceased in 1927, all output then being concentrated back in the Top Hard seam, the workings of which were now becoming quite extensive.