Why hasn't Peng Ji Iron Mine been mined?

The mining cost is low. Peng Ji, now Peng Ji Sub-district Office of Dongping County, is located in the south of Daqing River. Because of the low mining cost, Peng Ji Iron Mine refused to mine for a long time. Iron ore is a mineral aggregate containing simple iron or iron compounds that can be used economically, and it is an important raw material for iron and steel production activities.