[3] Mining properties of the area lie in an oval basin surrounded by crystalline rocks.

The bedrock of each of these gravel benches is clay, either red or blue according to exposure, in which are included beds of peat or brown coal.

The third bench, partly submerged, forms the greater portion of the higher dredging ground.

[7] The Mapuri tract on the Nechi River, a few miles below Zaragoza, was exploited by the Colombia Gold Mines Corporation.

[10] In November 1986, a terrorist group bombed a dredge in the river, forcing the temporary cessation to gold production in the area.

[12] The Field Museum of Natural History in Chicago was the recipient of a rare collection of gold ornaments, excavated from the basin of the Nechi River in 1918.

[13] In 1996, 29 archaeological sites, including Brisas Palagua, La Suiza, La Primavera, San Juan Bedout, Barcelona, El Amparo, Cano Regla, Palestina, Montenegro, and Tucuman, were found between the Nechí and Magdalena Rivers.

Their diet consists chiefly of river fish, rice, beans, plantains, meat and a great abundance of panela.