Abstract: Taking the 18^# thin vein of Jinchanggouliang Gold Mine for example， the similar material simulation experiment face-end drawing was conducted under the restraint of the inclined side walls. At the height of 12 and 14m and inclining to the side walls， the widths of the spheroid were measured as 1.7 and 2.1m， respectively， under the flow axial angle of 4°. Thus， the scopes of caving space were determined as 1， 2 and 3m， respectively. Under the optimum experiment between the recovery rate and the dilution rate， the optimum space was determined to be 1m under the height of 12 and 14m. The industrial test at the blasting test area under the space of 1m was accomplished when the 3D laser scanning CMS system was used to scan the tested areas. The results showed that a sound blasting effect was achieved with most part of the bulk ore rocks drawn， the top wall rocks remaining integrated， and the bottom side wall only partially under excavated.

Key words: steeply inclined thin veins, middle-deep hole blasting, caving space optimization, similar material experiment, industrial test