This story was published in 1989, in the waning years of the apartheid in South Africa. The apartheid was a system of racial segregation in South Africa which lasted from 1948 to 1994. During this time, a white minority controlled and oppressed the country of a black majority. In these waning years, crime and protests were common. In this story, Gordimer (a white South African) reflects fears of crime and violence which many people had under this system and as it headed towards transition.
She awakens to a mysterious sound and fears an intruder is in her house or trying to get in. This fear she illustrates alludes to the uncertain future which South Africa would have after the apartheid would be abolished. However, she comes to her senses and realizes that the noise is simply a creaky house which had been built upon an underground mine. So, the inclusion of the miners actually suggests a moment of logic, reason, and maybe even hope. Realizing her fear was misplaced, Gordimer indirectly suggests that any racial fear of "the other" is likewise misplaced. This is only one interpretation. But, in any case, her realization about the mine under her house dispels her fear of an intruder.