3908389

Information

• Patent Grant
• 3908389

• References
• Source

• Patent Number

  3,908,389

• Date Filed

  Not available

• Date Issued

  Tuesday, September 30, 1975
  49 years ago

• CPC

  • E21D23/0043 - and supported by two or more rows of struts parallel to the working face
  • E21D23/03 - having protective means

• US Classifications

  • 405 - Hydraulic and earth engineering