Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filedfiledCritical
Publication of BE676178ApublicationCriticalpatent/BE676178A/xx
E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
E21D23/00—Mine roof supports for step- by- step movement, e.g. in combination with provisions for shifting of conveyors, mining machines, or guides therefor
E21D23/0052—Mine roof supports for step- by- step movement, e.g. in combination with provisions for shifting of conveyors, mining machines, or guides therefor with advancing shifting devices connected therewith
Landscapes
Engineering & Computer Science
(AREA)
Mining & Mineral Resources
(AREA)
Life Sciences & Earth Sciences
(AREA)
General Life Sciences & Earth Sciences
(AREA)
Geochemistry & Mineralogy
(AREA)
Geology
(AREA)
Conveying And Assembling Of Building Elements In Situ
(AREA)
