When I entered the mines, i put the writ in the box... then I was in....
No i have finished the mines and want to get out. But i have no second writ ?! - what to do ? Is there another way out ? Or a second writ inside the mines ? ..

Check you first character. When you enter or leave the mine, the writ is given back to the first character, but it's unidentified, so it just looks like a regular scroll.

V.