3445139

Information

• Patent Grant
• 3445139

• References
• Source

• Patent Number

  3,445,139

• Date Filed

  Not available

• Date Issued

  Tuesday, May 20, 1969
  55 years ago

• CPC

  • E21C35/16 - by making use of the timbering, filling, or other supports
  • E21C25/14 - with equipment for cleaning the slit
  • E21C27/24 - by milling means acting on the full working face
  • E21C33/00 - Trucks or other devices for transporting machines for slitting or completely freeing the mineral from the seam
  • E21C41/18 - for brown or hard coal

• US Classifications

  • 299 - Mining or in situ disintegration of hard material
  • 198 - Conveyors: power-driven