Xinhui Gold Mine, The Residual Ore Resources Recovery Plan Optimization And Its Safety Evaluation

Mineral resource is no regeneration. It is greatly signficant for prolonging service life and enhancing mine integrated benefit to efficiently and safely recover residual ore. According to the JinXin gold mine’s engineering geology and residual ore resource survey, the paper adopt gray correlation theory to optimize the project of residual ore recovery, chose stope structure parameter based on mined-out area collapse mechanis, evaluated mined-out area’s stability, and applied comprehensive index classification method, fuzzy comprehensive evaluation and numerical simulation for safety evaluation. The main research achievement is as follow:Residual mineral resources are divided into point pillar, low-grade ore, rib pillar, roof and bottom residual ore, and heap. At the same time the residual ore resources’recovery project are put forward. The substitution method of artificial pillar is adopt for mine point pillar. The artificial pillar’diameter is3.0m in the505sublevel,2.7m in the525sublevel. Common room-and-pillar method is chosen to recover low-grade ore and rib pillar, whose stope strncture is45m×22m, the diameter of stage jamb of the505and525sublevel being respectively2.7m and2.5m, and the pillar space being7m.The comprehensive safety evaluation index classification of the mine gobs is respectinly0.54and0.491before and after residual ore’s mining. The gob’s stability has small variations, comprehensively evaluating the three test residual mining gob’s stability shows that the residual ore’s mining does not change the stability safety level, and the safety degree are III and IV level.The calculation result of FLAC3D for the artificial-column replacing mining method, presents that the mine gobs’strain has small change, the increment of vertical displacement of the roof and the surrounding rock is on the range of30～40mm, the increment of level displacement of the column and the rib pillar is tiny, and the plastic zone increases greatly,with the roof and floor damaging furthely and no failure zone penetrating.The result of simulation also shows that the stress changes little,the residual displacement of empty area decreases15～25mm, the damage of the roof and point pillar’s plastic zone is small, and the safety degree of the pillar reducing to0.5995. It’s obrious that the two residual ore’s mining scheme does not affect the overall stability of the gob’s, but some local roofs falling should be protected, and the safety management of the production process should be strengthen.Through the application of the artificial-column replacing mining method, with the designing of residual ore’s mining preparation, blasting, drawing and hauling, and taking the coesponding security measures of residual ore’s mining based on the safe evaluation of the gob’s, the residual ore’s recovery rate reached95%.