The World, the Flesh and the Devil [1959 - USA] sci fi

Ralph Burton, a young black man, is working underground in central Pennsylvania in examining a long abandoned mine shaft when the tunnel collapses, trapping him inside. When he is eventually able to dig himself out several days later, he discovers a world much different than before his confinement in that a nuclear war has seemingly decimated the globe, at least his surroundings in there being no survivors that he can see. He decides to drive to New York City to see if life, or lack of, is the same there, which it seemingly is so. As he comes to the reality of his existence several weeks later of perhaps being the last person alive, he encounters another survivor, a young white woman named Sarah Crandall, who was well aware of him before he was of her, she not initially showing herself in adjusting to her new reality. Despite their differences in at least the way each copes with this new world, they not only bond in each providing the other with the necessaries of life, both physically and mentally, but they seemingly start to fall in love. Their copacetic world is interrupted when a third survivor enters their midst, middle aged white man Benson Thacker. What Benson's entrance brings to light is the pre-war mentality where the biggest issue for what each wants and/or "deserves" may be based on the color of their skin.