Foundation Coal Holdings Inc. says it has found an unconventional way to cut health costs: Seek out the nation's best care and give workers incentives to use it. About two-thirds of operations have proven to be cheaper at better-rated hospitals out of state, and even when the price was higher, the company saved money by reducing misdiagnoses, complications, and repeat procedures. The experiment could now be a model for politicians and insurers seeking to curb the growth in U.S. healthcare spending.