dong guo kui meng zhao (2 Ergebnisse)

paperback. Zustand: New. Paperback.Pub Date:2022-12 Pages:148 Language:Chinese Publisher:China University of Mining and Technology Press The western mining areas of my country are rich in thick and extra-thick coal seams. which are suitable for full-thickness mining with large mining height. However. with the increase of mining height. the working face pressure is enhanced. the impact of roof and the frequency of coal wall spalling gradually increase. which puts higher requirements on the key support equipment hydrau.

paperback. Zustand: New. Language:Chinese.Paperback. Pub Date: 2014-12-9 Pages: 192 Publisher: Social Sciences Academic Press book is a microcosm of the sunrise long history and splendid culture. outlined the sunrise from 100.000 years ago. the pigeon hole people. especially from 5000 Hongshan Culture period began many years ago. today's reform and opening up. the whole process of construction and development. focusing on the major events that occur on the sun and typical characters of history. financial history of d.