The Omai mine is one of the largest gold mines in the Guyana and in the world. The mine is located in the north-west of the country in Cuyuni-Mazaruni. The mine has estimated reserves of 3.7 million oz of gold.
On 19 August 1995 a tailings dam broke and leaked tailings into the Essequibo River. 351 fish were killed. A class action tried to sue the mining company for 2 billion dollars, but the case was dismissed.