“This isn’t our first rodeo” has become a catchphrase among oil-industry executives who are laying off workers and dialing back spending in the wake of tumbling crude-oil prices. But for many sand producers, this is their first time on the bucking bronco that is the cyclical energy business—and not all of them are ready for the wild ride, industry analysts say. Sand is an important ingredient in hydraulic fracturing, or fracking, which has pushed American oil output above 9 million barrels a day, rivaling the production of Saudi Arabia or Russia. Sand companies’ biggest customers used to be golf courses and glass manufacturers, but the oil boom brought energy clients to their door and now roughly 60% […]