Title:
【発明の名称】竪孔掘削工法
Document Type and Number:
Japanese Patent JP2827020
Kind Code:
B2
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Inventors:
YOKOYAMA HIROSUKE
Application Number:
JP26371389A
Publication Date:
November 18, 1998
Filing Date:
October 09, 1989
Export Citation:
Assignee:
YOKOYAMA KISO KOJI KK
International Classes:
E21B11/04; E21B3/06; E21B6/00; E21B6/06; E21B7/20; (IPC1-7): E21B7/20; E21B6/00
Attorney, Agent or Firm:
Denichiro Kido (2 outside)