Bismarck - Standing Rock Sioux chairperson Dave Archambault, who has been the face and voice of the Dakotas tribe during its long and futile attempt to block the four-state Dakota Access pipeline, has lost his bid for re-election.Unofficial results from the general tribal election showed that Archambault received only 37% of about 1 700 votes cast. His opponent, longtime tribal council representative and wildlife official Mike Faith, received 63%. Archambault conceded defeat in a statement on Thursday."I will continue to advocate for the issues facing our community and look forward to exploring new opportunities," he said. The tribe opposed the $3.8bn pipeline built by Texas-based Energy Transfer Partners over fears it would harm cultural sites and the tribe's Missouri River water supply - claims rejected by ETP. Protests failed to stop the pipeline, and it began moving North Dakota oil through South Dakota and Iowa to a distribution point in Illinois on June 1. The Standing Rock and three other Sioux tribes are still fighting the pipeline in federal court.A protest camp on federal land just north of the reservation and near the area where the pipeline skirted tribal land drew hundreds and sometimes thousands of pipeline opponents, some of whom clashed with police. There were 761 arrests between August and February.