The Bou Craa phosphate mine is located 100 km inland from the capital city of El Aaiun. The Bou Craa area's phosphate resources were discovered by the Spanish in 1947; phosphate deposits are near the surface and are very pure. Phosphate mining, however, did not begin until the 1960s. Since 1974, the Bou Craa mining operation has been growing steadily. In 2000, the mine covered more than 1 225 hectares. In 2001, its output was approximately 1.5 million metric tonnes of phosphate. Morocco controls the area of Western Sahara where the mine is located and jointly operates the mine with Spanish interests. While the mine amounts to only two or three per cent of Morocco's phosphate production, the reserves are valuable because of the uranium that can be extracted from them. The phosphate-containing rock is transported from the Bou Craa mine to the port at El Aaiun via a 100-km-long conveyor belt, which can move 2 000 metric tonnes of rock per hour. The conveyor belt is visible as a straight line from the upper left corner toward the centre of the images. Note the difference of color between the two side of the conveyor belt, due to the drifting sand spreading from the belt's path blowed by main wind.