A.煤柱設(shè)計(jì)所采用的參數(shù)及其依據(jù) B.煤柱設(shè)計(jì)的批準(zhǔn)文號(hào) C.圍護(hù)帶及煤柱角點(diǎn)的坐標(biāo) D.受護(hù)對(duì)象及其名稱(chēng)
A.4mm B.3mm C.2mm D.5mm
A.2mm B.4mm C.5mm D.3mm