Group 1 - The company Erdos City Guoyuan Mining Development Co., Ltd. has obtained a patent for a "5G-based underground communication signal testing method" with authorization announcement number CN 119676753 B, applied for on December 2024 [1] - Erdos City Guoyuan Mining Development Co., Ltd. was established in 2005 and is primarily engaged in coal mining and washing [1] - The company has a registered capital of 1,477.2745098 million RMB and has participated in 5,000 bidding projects, holding 116 patents and 34 administrative licenses [1]