Dong-Ah Geological Engineering Co., Ltd. engages in the research and construction business. It operates through the following business divisions: Tunnel, Ground Improvement, and Engineering. The Tunnel division provides shield tunnel boring machine and pipe jacking services. The Ground Improvement division improves soil's engineering property and stability. The Engineering division deals with general planning, designing, and construction services. The company was founded on March 26, 1971 and is headquartered in Busan, South Korea.