The Barco oil concession was one of the main concessions in Colombia during the early development of its petroleum industry, the other being the De Mares concession. Oil was first found in the Norte de Santander department near the border with Venezuela in 1905, but development did not start until 1936. A joint venture between the Texas Corporation and Socony-Vacuum sank the wells and built a 263-mile (423 km) pipeline across the mountains and through swampy jungle to the Caribbean coast at Coveñas. Workers were harassed by Motilone Indians defending their territory, and several died. The concession began operation in 1939 and continued into the 1960s, when it began to be depleted. Other fields in the region are still productive.