Their job is to turn the material excavated in Quarry Junction into concrete at the nearby refinery. The workers appear only after removing the deathclaws from Quarry Junction. This can done by talking to Chomps Lewis in Sloan who will ask the Courier to solve the deathclaw infestation in Quarry Junction by giving the unmarked quest Claws Out. Until the workers can resume their duties the saloon owner Ike will be complaining about the lack of business.
Claws Out: The Boulder City workers are not present in Boulder City or the Big Horn Saloon in the beginning of the game due to the infestation of Quarry Junction by deathclaws. The concrete production as a result has been stopped since the raw material needed for production is not flowing any more.