The cylindrical object, found on Thursday in Kachin state, is 4.5m long and 1.2m wide. Another piece of metal with Chinese writing on it tore through the roof of a nearby house at about the same time, but no injuries were reported.
It is thought that the incident might be related to the launch of a Chinese satellite. A Chinese Long March 11 rocket lifted off from the Jiuquan Satellite Launch Centre on Wednesday night, carrying an experimental satellite.
Officials from the local Defence Service said it bounced 150ft and landed in a muddy area of the mine, according to the Global New Light of Myanmar newspaper.
"We were all afraid of that explosion," villager Ko Maung Myo told the Myanmar Times. "Initially, we thought it was a battle. The explosion made our houses shake. We saw the smoke from our village."
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