Excavation of possible emperor's tomb off XI'AN, China, Feb. 29 (UPI) -- A possible tomb of the last emperor of China's Qin Dynasty won't be excavated until studies are conducted for subsequent protection plans, authorities said. The cultural heritage bureau of Shaanxi province had proposed to excavate the suspected resting place of Ziying, the grandson of Emperor Qinshihuang (259 BC-210 BC), the first person to unify China, but the proposal was rejected by the State Administration of Cultural Heritage, China's state-run Xinhua News Agency reported. The tomb, discovered in 2003, lies about 500 yards northwest of the Qinshihuang Mausoleum near the provincial capital of Xi'an -- site of the famous Terra Cotta Army -- and authorities said they were concerned about new excavation causing damage to the mausoleum. In an official statement, the state administration said thorough research and evaluations should be conducted in order to develop a proper protection plan. Historical records show the young emperor Ziying held the title for just 46 days before the empire was overthrown by rebels and he was killed. His burial site has remained a mystery ever since.