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Priority to NL6510418ApriorityCriticalpatent/NL6510418A/xx
Publication of NL6510418ApublicationCriticalpatent/NL6510418A/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
E21D23/04—Structural features of the supporting construction, e.g. linking members between adjacent frames or sets of props; Means for counteracting lateral sliding on inclined floor
E21D23/06—Special mine caps or special tops of pit-props for permitting step-by-step movement
E—FIXED CONSTRUCTIONS
E21—EARTH OR ROCK DRILLING; MINING
E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
E21D17/00—Caps for supporting mine roofs
E21D17/01—Caps for supporting mine roofs characterised by the shape of the cap, e.g. of specified cross-section