It was not that he was afraid of the goblins, but that he was afraid of their finding out that they were watched, which might have prevented the discovery at which he aimed.

Sometimes his haste had to be such that, when he reached home towards morning, his string, for lack of time to wind it up as he 'dodged the cobs', would be in what seemed most hopeless entanglement; but after a good sleep, though a short one, he always found his mother had got it right again.

There it was, wound in a most respectable ball, ready for use the moment he should want it! 'I can't think how you do it, mother,' he would say.
'I follow the thread,' she would answer--'just as you do in the mine.' She never had more to say about it; but the less clever she was with her words, the more clever she was with her hands; and the less his mother said, the more Curdie believed she had to say.

But still he had made no discovery as to what the goblin miners were about..