The Kinta Valley, one of the richest tin mining areas in Malaya, accounted for most of the country's tin exports to the United States. To protect it from the communists, on 1 May 1952, the Perak Chinese Tin Mining Association established the Kinta Valley Home Guard (KVHG). Often described as a private Chinese Army, most of the KVHG's Chinese members had links to the Kuomintang. Many of the Kuomintang guerrillas were absorbed from the Lenggong area, where there were also members of Chinese secret societies whose main purpose was to defend Chinese property against the communists. Throughout the first emergency the British authorities and their Malayan collaborators fought against the communists. This continued even after the proclamation of the independence of the Federation of Malaya, on 31 August 1957. As a result, most of the communist guerrillas were successfully pushed across the northern border into Thailand.