The ornamental design for a grindingelement, as shown and described.
FIG. 1 is a top plan view of a grinding element in accordance with the present invention;
FIG. 2 is a perspective view of the grinding element of FIG. 1;
FIG. 3 is a sectional elevation view of the grinding element taken along line 3-3 of FIG. 1; and,
FIG. 4 is a left side elevation view of the grinding element of FIG. 1.
The evenly dashed broken lines in the drawings depict unclaimed environmental subject matter. The unevenly dashed broken lines in the drawings depict the boundaries of the claimed design and form no part thereof.