There are five Bureaus of Engineers in North Korea, and each is in charge of different fields: The first bureau is in charge of building ordinary tunnels such as those for the Pyongyang Subway System; the second, the construction of hydraulic power stations; the fourth, the construction of vertical pits in Anju Coal Mine; and the fifth, the construction of a two-track railway between Pyongyang and Chongjin. The Third Bureau of Engineers [also known as the Third Sappers Bureau] is a military unit under the party Central Committee that specializes in building nuclear facilities.This bureau operates its own trading firm, Puhung Trading Corporation, to procure materials from overseas. The third bureau receives special treatment -- the soldiers of this unit receive 1.2 kg of rice and pork per day. In North Korea, this amount is considered to be a very good supply of materials.