Job Committees, like shop committees in other industries, emerged in Broken Hill during the height of the Great Depression, thrived in the decade 1935-45, and all but vanished during the Cold War. The committees were a focal point for struggle and contestation between the various competing interest groups and ideologies vying for ascendancy in the local miners’ union, the Workers Industrial Union of Australia. This study of job committees seeks to show that the dynamics of trade union behaviour are forged by a series of complex and contradictory human relationships. The processes associated with the success and eventual isolation of the job committees should not be seen as a failed attempt by the rank and file to democratise a bureaucratic leadership. Rather, they should be seen as an ongoing dialogue between various interest groups within the union whose orientations, expectations and priorities changed with the altered context of wage and employment levels, ideology, occupation, and location within the union hierarchy. In this sense job committees and their activist participants performed an intermediary role between leadership and membership.