The Missing Place by Sophie Littlefield

What they say....  The booming North Dakota oil business is spawning “man camps,” shantytowns full of men hired to work on the rigs, in towns without enough housing to accommodate them. In such twilight spaces, it’s easy for a person to vanish. And when two young men in their first year on the job disappear without a trace, only their mothers believe there’s hope of finding them. Despite reassurances that the police are on the case, the two women think the oil company is covering up the disappearances—and maybe something more.

Colleen, used to her decorous life in a wealthy Massachusetts suburb, is determined to find her son. And hard-bitten Shay, from the wrong side of the California tracks, is the only person in town even willing to deal with her—because she’s on the same mission. Overtaxed by worry, exhaustion, and fear, these two unlikely partners question each other’s methods and motivations, but must work together against the town of strangers if they want any chance of finding their lost boys. But what they uncover could destroy them both...

What I say.... This was a hard book for me to read, as my daughter's boyfriend currently works on an oil rig in North Dakota.  So it was a little stressful to read about the environment there, although the book is probably a lot closer to the truth than I care to know.
The difference between the way the two mothers lived was a common theme, although as you read it, you realized anytime there are two mothers who love their children, there are more commonalities than differences.
It was a pretty intense book, and I found myself staying up to finish it.  What I liked was that once the mystery was solved didn't mean the end of the story, Colleen didn't suddenly understand what she'd been doing wrong all along, Shay didn't have an ending tied up with a bow, and they didn't end up best friends forever.  I like a book that is more like real life, warts and all.