The Pressure Arch Theory. 0.2 kg/ cm2 per metre depth note it. 

Excellent in simple language

🤩Much love from China, kinda sad its not completely in English, but still comprehensible with a bit effort of guessing. Great lecture and research theories specified for both Indian and Chinese coal mines.

Bhut hi acche se samajh aaya sir 🙏🙏🙏🙏

In one place read as horizontal not vertical when I was explaining zone 4

Helpful video

Good efforts sir

Very useful sir 👏

🙏🙏🙏🙏

👍🏻

🙏

Sir dome and arch theory same h kya