Abstract: The invention relates to a levelling bar for coking ovens, for levelling the cones of discharged coal which form under the filling holes of the oven chamber during the filling process. The levelling bar consists of two cheeks, such as plates (1), which extend essentially over the entire length of the ranged at a distance from each other depending on the width of the oven chamber, and parallel to each other. They are also interconnected and are essentially vertical. The levelling bar also has transversal coal carriers (2) which are arranged in the intermediate space delimited by the cheeks (1) at a mutual distance, one behind the other and which only extend over part of the cross-sectional surface of the levelling bar formed between he cheeks (1). The height (3) of the coal carriers (2), which take up the entire interval between the cheeks, is less than the height (H) of the cheeks (1) and the cheek form a gas channel (6) above the coal carriers (2) which is essentially free of built-in components.

Abstract: Shifts in rock strata are measured be inserting into a bore hole in the rock a conductive tube in which an insulated conductor runs along the length and the continuity is measured between the conductor and the tube. When conductivity is detected, the shift in the strata amounts to the distance required for the tube wall to break the insulation and create an electrical content between the tube and the conductor.