The two Koreas will wrap up working-level talks on Friday on trading raw materials from the South for natural resources in the North.

An official from the Unification Ministry said that minor differences have made it uncertain whether the two sides will reach an agreement on the issue.

South Korea hopes to gain exclusive rights to developing at least two mines in North Korea’s Hamgyeong Province, while offering Pyongyang raw materials for light industry products such as shoes and clothing.

The country proposed a joint survey of the two mines Wednesday on the first day of talks held in the North Korean border city of Gaesong.

The South Korean delegation is led by Lee Ung-hui, chief of inter-Korean economic cooperation at the Unification Ministry.

The talks were launched as part of an agreement to carry out cross-border railway tests. The South agreed to provide 80 million dollars worth of raw materials in exchange for natural resources and development rights from the North.