And if Curdie worked hard to get her a petticoat, she worked hard every day to get him comforts which he would have missed much more than she would a new petticoat even in winter.

Not that she and Curdie ever thought of how much they worked for each other: that would have spoiled everything.
When left alone in the mine Curdie always worked on for an hour or two at first, following the lode which, according to Glump, would lead at last into the deserted habitation.

After that, he would set out on a reconnoitring expedition.

In order to manage this, or rather the return from it, better than the first time, he had bought a huge ball of fine string, having learned the trick from Hop-o'-my-Thumb, whose history his mother had often told him.

Not that Hop-o'-my-Thumb had ever used a ball of string--I should be sorry to be supposed so far out in my classics--but the principle was the same as that of the pebbles.
The end of this string he fastened to his pickaxe, which figured no bad anchor, and then, with the ball in his hand, unrolling it as he went, set out in the dark through the natural gangs of the goblins' territory.