Robert W. Johns

Follow

Person

Calgary, CA

People

Patents Grantslast 30 patents

Information Patent Grant
Hook plough apparatus for longwall mining
- Patent number 4,013,320
- Issue date Mar 22, 1977
- World Oil Mining Ltd.
- Robert W. Johns
- E21 - EARTH DRILLING MINING
Information Patent Grant
Method for longwall mining with side-by-side arch sections
- Patent number 3,980,340
- Issue date Sep 14, 1976
- World Oil Mining Ltd.
- Robert W. Johns
- E21 - EARTH DRILLING MINING
Information Patent Grant
Tunnel layout for longwall mining using shields
- Patent number 3,960,408
- Issue date Jun 1, 1976
- World Oil Mining Ltd.
- Robert W. Johns
- E21 - EARTH DRILLING MINING
Information Patent Grant
Longwall mining system and archshield for mining tar sands, oil sha...
- Patent number 3,958,830
- Issue date May 25, 1976
- World Oil Mining Ltd.
- Robert W. Johns
- E21 - EARTH DRILLING MINING
Information Patent Grant
Mining machine longwall propulsion means
- Patent number 3,954,300
- Issue date May 4, 1976
- World Oil Mining Ltd.
- Robert W. Johns
- E21 - EARTH DRILLING MINING