For years, Mary Drangstveit could feel the shale boom reverberating in her kitchen. This spring, oil prices crashed and the rattling ceased. t brought relief for her and distress for some others in her community. Digging stopped at the sand mine next door in Blair, Wis., which had rumbled since 2015 to supply drillers with silica they blasted into shale to let out oil and gas. The coronavirus pandemic and a switch by drillers to cheaper sand accomplished what locals like Mrs. Drangstveit, 77, couldn’t in their efforts to fight the mine at town meetings and court.

The mine’s owner, Hi-Crush Inc., filed for bankruptcy in July. Rival Covia Holdings Corp. , an Ohio company with Wisconsin mines, did so in June. Other mines have closed or cut hours. “This has been the most peaceful summer of the last six years,” Mrs. Drangstveit said.

The peace has been disquieting for locals like Joshua Brush, who mowed grass at Hi-Crush properties. He lost his top customer and says $6,530.45 of unpaid invoices are “a huge financial hardship for me and my family.”

The collapse in oil prices this year has squeezed energy-centric economies from Russia to Venezuela, idled drilling rigs in the North Sea and Gulf of Mexico, bankrupted U.S. shale producers and helped push Exxon Mobil Corp. out of the Dow Jones Industrial Average.

Wisconsin doesn’t produce a drop of oil or gas, but there has been a bust there, too, as there has been along the entire industrial ecosystem that supported fracking. Dozens of idled open-pit sand mines dot the farmland near where Wisconsin, Minnesota, Iowa and Illinois meet along the Mississippi River. Hundreds of mine workers in the sparsely populated region have lost jobs. Many others, like Mr. Brush, are suffering alongside them.

Companies that supplied trucks, lubricants and drilling tools have been bankrupted. Steelworkers in Youngstown, Ohio, have lost jobs providing pipe to the oil patch. Apartments and hotels hastily built to house roustabouts in North Dakota and remote parts of Texas have emptied.