that the first nationalist guerrilla groups began to form in Tanzania and other African countries. The strong industrial and agricultural development that did occur throughout the 1950s, 1960s and early 1970s was based on Portuguese development plans, and also included British and South African investment. In 1959–60, Mozambique's major exports included cotton, cashew nuts, tea, sugar, copra and sisal. Other major agricultural productions included rice and coconut. The expanding economy of the Portuguese overseas province was fuelled by foreign direct investment, and public investment which included ambitious state-managed development plans. British capital owned two of the large sugar concessions (the third was Portuguese), including the famous Sena states. The Matola Oil Refinery, Procon, was controlled by Britain and the United States. In 1948 the petroleum concession was given to the Mozambique Gulf Oil Company. At Maotize, coal was mined; the industry was chiefly financed by Belgian capital. 60% of the capital of the was held by the , 30% by the Mozambique Company, and the remaining 10% by the Government of the territory. Three banks were in operation, the , Portuguese, Barclays Bank, D.C.O., British, and the (a partnership between Standard Bank of South Africa and mainland's ). Nine out of the twenty-three insurance companies were Portuguese, which included insurance companies related to Fidelidade throughout its history. 80% of life assurance was in the hands of foreign companies which testifies to the openness of the economy. The Portuguese overseas province of Mozambique was the first territory of Portugal, including the European mainland, to distribute Coca-Cola. Lately the Oil Refinery was established by the (SONAREP) — a Franco-Portuguese syndicate. In the sisal plantations Swiss capital was invested, and in copra concerns, a combination of Portuguese, Swiss and French capital was invested. The large availability of capital from both Portuguese and international origin, allied to the wide range of natural resources and the growing urban population, lead to an impressive growth and development of the economy. From the late stages of this notable period of high growth and huge development effort started in the 1950s, was the construction of Cahora Bassa dam by the Portuguese, which started to fill in December 1974 after construction was commenced in 1969. In 1971 construction work of the Massingir Dam began. At independence, Mozambique's industrial base was well-developed by Sub-Saharan Africa standards, thanks to a boom in investment in the 1960s and early 1970s. Indeed, in