a. Of a mine: Admitting of being worked or drained by means of a level or levels.
1805. R. Forsyth, Beauties Scotl., III. 411. The mine … is nearly 700 feet above the level of the valley, and must therefore always be level-free.
1883. Gresley, Gloss. Coal-Mining, Level-free, old coal or ironstone workings at the outcrop, worked by means of a day level driven into the hillside.
