已知矿井工业储量为8200万吨,各种保护煤柱的损失量为工业储量的的10%,设矿井年生产能力为120万吨,C=0.8,K=1.4,试求该矿井的服务年限。()
A campus emergency ______ occur at any time of the day or night, weekend, or holiday, with little or no warning.
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