Study On The Recovery Methods Of Orelayer In The Process Of Lan Jian Lron Mine From Open-pit To Underground

After decades of open-pit mining, Lanjian Iron Mine has been officially turn to underground mining and used the highly efficient and safe sublevel caving. Unlike many open-pit mining in domestic and foreign, Lanjian Iron Mine has adopted measure which caving top segmented manner to form ore mining overburden, recently, Covering layer has been formed. It is a little early to estimate, the value of the ore mining overburden will reach one billion dollars, However, there is no mention that whether and how to recycle ore mine overburden in the mining design. Because Lanjian iron mine bodies are inclined orebody which dip is about 40 to 50. With the mining segment continuou down, if appropriate measures are not taken timely to recovery of ore overburden, the ore overburden will inevitably gradual loss in the footwall of the ore body.According to the different ways to form different regions of mine overburden, it conducted a similar physical experiment in the laboratory. In a clear understanding the shape, thickness and composition of the ore overburden, and puting forward to the method of form a rock overburden which is induced caving method. It design different ways of recovery experiments, include the way of no dilution drawing, low dilution drawing, cut-off grade drawing and step away from the collapse of the amount of ore to 100%. By comparing the different of the experimental data, no dilution drawing mode is the best economic way to the central region of orebody, if calculated in accordance with the recovery of 80.33%, then 1,577,600 tons of ore will be recovered. It made a research to the recovery of footwall ore overburden, studies have shown that if the footwall ore mining in the next segment have no opportunity to recover, It should be used the way of cut-off grade drawing, If the next segment have the chance of recovery, it should be used the way of no dilution drawing, After using these two draw methods in footwall, it will recycle 859,400 tons of ore and bring considerable economic benefits.