The Coal Industry Nationalisation Act 1946 provided for the complete nationalisation of the coal industry and on 12 July 1946 established the National Coal Board (NCB). This body, appointed on 15 July 1946, was made solely responsible for managing the industry and running it on business lines, except that the Minister of Fuel and Power, after consulting with the board, might give it directions of a general character. The minister appointed the members of the board, numbering nine in 1946, raised to a maximum of eleven of which eight should be full-time in 1949 and to a maximum of fourteen in 1973, and he presented the NCB's reports to Parliament. In October 1969 these general powers passed to the Ministry of Technology, in October 1970 to the Department of Trade and Industry, and in January 1974 to the Department of Energy. The eight departments of the National Coal Board headquarters - Production, Marketing, Finance, Labour Relations, Manpower and Welfare, Scientific, Legal and Secretary's - made up the National Board and formed the top tier of a four tier system. At the lowest level were the coalfields (each colliery had its own manager) which were divided into 48 geographical areas under the control of an area manager. The areas were grouped into 8 geographical divisions under a divisional board which reported to the National Board. On the vesting date, 1 January 1947, the productive assets of the 800 or more private colliery undertakings and the service contracts of their employees were transferred to the National Coal Board, as were the coal deposits and other assets of the Coal Commission and the functions and staff of the district selling schemes. Subsequently the board acquired other responsibilities, notably that for the coal survey from the Department of Scientific and Industrial Research in August 1947, and that for miners' hostels from the Ministry of Labour and National Service in the same year. In 1951 it took over some of the functions of the Miners' Welfare Commission, and in April 1952 it acquired responsibility for opencast coal mining from the Ministry of Fuel and Power. In 1973 it formed two holding companies, NCB (Coal Products) Ltd. and NCB (Ancillaries) Ltd. to handle two major aspects of its work not directly related to deep and opencast mining. The Coal Industry Act 1977 gave the board new powers in respect of the acquisition, treatment and sale of petroleum and of working minerals other than coal or petroleum which were discovered in the course of prospecting for or working coal and petroleum. The NCB was headed by a chairman and deputy chairman; each of the other members took charge of an executive department or research establishment. The main functions of the board as a whole were to decide and set objectives for the industry, to lay down policy directives and the limits within which management must work, to hold management to account and to provide for the future by means of research and development, and the recruitment and training of staff. It was also responsible for promoting the safety, health and welfare of employees. Many of these functions were exercised at the area and colliery level, a chain of command which replaced the previous five-tier system in 1967. The board itself continued to settle national policy, conduct national negotiations, obtain capital and provide common services such as scientific research. Before 1967 the divisional boards also exercised wide discretion in the forming of policy and applying it at area and colliery level. The headquarters departments advised the board on general policy and objectives, provided information and executed policy, and they also operated certain national services, including central workshops and the rescue service; and regional services in non-coalfield areas. On 1 January 1987, the NCB became the British Coal Corporation, which was wound up in 1997.