Patents Represented by Attorney Conrad B. Houser
  • Patent number: 5782539
    Abstract: A mining process that consists of a combination of surface mining and underground mining techniques carried out in a novel extraction sequence. The coal seam is first mined by surface-mining stripping methods to produce a highwall. Roadways to a predetermined distance underground from the surface highwall are then developed using continuous mining equipment, so that a panel of coal with a minable underground face or wall is blocked out. A longwall is then set up at the face and the panel is mined in retreat toward the surface highwall to a safety barrier determined by the highwall slope. Adjacent panels are successively developed and extracted by longwall mining, thereby permitting the recovery of substantially all coal reserves between the surface highwall and the predetermined distance at which the underground wall was set up.
    Type: Grant
    Filed: November 16, 1995
    Date of Patent: July 21, 1998
    Inventor: Randall D. Peterson