Abstract: One of the technical problems for efficient mining in underground metal mines,is how to achieve mechanized charging in up-hole.Especially when the wall of up-hole is distorted and offset because of blast-hole being squeezed,the conventional charging method may be useless,or the poor charging results in poor blasting quality,and then the normal mining will not be carried out.The paper describes the typical examples for BCJ-charging truck in underground metal mines,and especially new progress in the site-mixing and loading technique in the up-hole（min.borehole diameter 90mm,max.charging length ≥30 m) in Shuangyashan iron mine,has been achieved,which provides the technical support for tight blasting mining of long up-hole.

Key words: Underground mine, Up-hole, Charging truck, Site mixing and loading technology, Blasting