张家洼矿山公司小官庄铁矿北区采场一期工程开采深度为500～550m。上盘是巨厚的第三系粘土质砂岩(红板岩),遇水软化膨胀;局部有石炭系灰岩。下盘闪长岩是成矿母岩,但接触带蚀变严重,破碎且软弱结构面发育。矿体由于石炭纪的风化剥蚀作用,上部形成密集结构裂隙,裂隙间充填有泥状红板岩和风化物。由 Zhangjiawa Mining Company Xiaoguanzhuang Iron Mine North District stope a mining depth of 500 ~ 550m. The upper plate is a thick Tertiary clay sandstone (red slate), water softening expansion; local carboniferous limestone. The lower diorite is a metallogenic parent rock, but the contact zone is seriously altered, broken and weakly developed. Due to the weathering and denudation of the Carboniferous, the ore body formed dense structural fractures in the upper part, and the muddy red slate and weathering material were filled in the fractures. by