[1]Hebei Provincial Academy of Environmental Sciences Shijiazhuang 050031 China;
[2]Institute of Hydrogeology and Environmental Geology CAGS Shijiazhuang 050061 China;
[3]Geophysical Exploration Academy of China Metallurgical Geology Bureau Baoding Hebei Province 071051 China;
Manzhouli; High-precision magnetic measurement; Middle-gradient method; IP field prospecting; Controlled source audio-frequency magnetotellurics; Polymetallic ores;