The Ironmaster's Girl by Una Horne
In the poverty-stricken mining town of Winton, Katie Benfield lives with her grandparents to ease the pressure on her own mother's full house. Despite the hardships, Katie achieves her goal of becoming a probationer nurse. She is determined to have a career, and even puts off marrying her childhood sweetheart Billy to achieve her dreams. Then tragedy strikes, and Billy and her grandfather are both killed in a mining accident. Distraught, Katie finds herself vulnerable to the advances of local ironmaster, Matthew Hamilton, a married man. Thrown out by her grandmother, isolated and pregnant, Katie's future is far from certain. And then Matthew Hamilton offers her an alternative to a home for unmarried mothers, but only if she forgoes her principles and becomes his mistress...