BLACK HAWK, S.D. — Six years ago, a huge sinkhole opened in a residential neighborhood in this unincorporated town that serves largely as a bedroom community for Rapid City. After all that time, the homeowners directly affected and those put at risk by the sinkhole have received no financial relief for their ongoing or potential losses. Meanwhile, the immediate area around the sinkhole in the northeast end of the Hideaway Hills subdivision — eas…