Abstract: Disclosed is a method for evaluating thicknesses of cobalt-rich crusts on seamounts, which comprises following steps: dividing a study area of cobalt-rich crusts into geological grid units, assigning crust thickness values to geological grid units; obtaining the crust thicknesses of the geological sampling stations in a preset influence range in the adjacent areas based on geological sampling station information; estimating the crust thicknesses in a certain distance range of the stations by a “distance-slope” spatial interpolation method, and through a spatial similarity of a crusts spatial distribution caused by a relationship between the distance and the slope, assigning values to grid units outside adjacent areas and within an influence range of the spatial similarity relationship; assigning values to the geological grid units that failed to obtain crust thickness value through an expected assignment method, and obtaining the crust thicknesses of the study areas.

Abstract: A drill bit for cutting formation comprises a bit body, a plurality of cutters, a plurality of blades with pockets to accommodate the cutters respectively. Each of the plurality of cutters has an ultra-hard layer, two side facets extending obliquely inward from the substrate to a top surface of the ultra-hard layer, a convex portion between the two side facets. The convex portion comprises a transition surface and the transitional surface is convex as it extends between adjacent the two side facets. The curvature of the transitional surface varies along the cutter axis with the curvature at the cutting edge larger than the curvature of the cutter circumferential surface.