Zhengzhou Coal Mining Machinery (Group) Co., Ltd (Hereafter referred to as ZMJ) was established in 1958. After over half a centurys development, ZMJ has become the largest company in the world in respect of RD and manufacturing powered roof support used for fully mechanized coal mining. Mar 31, 2021 Type Size MB Record date Results date Speed (days) Report filed Quarterly Report 2021-03-31 2021-04-26 26 Annual Report 19.0 2020-12 Company profile for Zhengzhou Coal Mining Machinery Group Co. Ltd. including key executives, insider trading, ownership, revenue and average growth rates. View detailed 601717.CN description ...