In 1972, when Texaco completed construction of a pipeline to funnel oil to the Pacific coast, Ecuador instantly became the second-largest oil exporter in Latin America, after Venezuela.

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Nigeria could funnel its oil revenues into a more efficient financial system that could provide capital to the private sector to build roads and power stations and expand private enterprises, such as farming.

ECONOMIST: Nigeria's prospects

Critics have also accused Sonangol -- which is both concession-granter and regulator of the industry -- of acting as a way to funnel part of the oil revenues to the political elite.

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To make an oil-collecting caisson, such a pile would be used as a collar around a funnel-topped tube that would sit over the leak.

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The dome will resemble an inverted funnel, with a pipe leading up to ships waiting at the surface that would take away the oil.

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