With your cursor inside the minesweeper window type "XYZZY" then press Shift-Enter and Enter. A white dot should appear in the upper-left corner of the screen. If it turns black, your cursor is resting on a mine.

Slot: Narrow vertical or inclined opening excavated in a deposit at the end of a stope to provide a bench face. Stope: Large exploitation opening, usually inclined or vertical, but may also be horizontal.