There is a coal layer on the clay of direct roof.This layers is unstable and easy tofall down after mining and enable the gas to gush out.
团溪锰矿的直接顶之上有一煤层,且不稳定,采后容易垮落,造瓦斯涌出。
There is a coal layer on the clay of direct roof.This layers is unstable and easy tofall down after mining and enable the gas to gush out.
团溪锰矿的直接顶之上有一煤层,且不稳定,采后容易垮落,造瓦斯涌出。
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