QINLING gold ore veins 9 genus warmed liquid filling and replacement gold sulphides quartz veins, as veins, lenticular stratoid output, local expansion, contraction and branching complex phenomena, on the strike and dip It is undulating. The average barrier is 0.74m, the average inclination is 20°, and the average grade is 17.78g/t. The upper and lower plates are mainly pegmatite, mixed rock, and partially biotite granite and gneiss . The rock solidity coefficient f=13～16, the joints are moderately developed, relatively stable, but broken in the fault and near-surface weathering zone. Using the comprehensive method, the stage height is 22m, the length of the nugget is 60m, the width of the bottom column is 3m, and the width of the top column is 2m. Generally, the straight working face is taken along the direction. The mining site is supported by pillars, waste rock shovel or metal anchors. According to the stability of the roof, the thickness and grade of the ore body change. The pillars and sarcophagi are generally irregularly arranged. The size of the pillar is 2×3m, the supporting area is 150-200m2, and the proportion of the pillar reserves is generally less than 15%. It is used to go back to the mining column in order from the top and the bottom, and in the upper stage, after the mining block is completely finished and the powder ore is cleared. The top column is generally first collected, but it needs to be temporarily retained when the upper stage cannot be scrapped along the vein roadway. Finally, the bottom column can be recovered separately, or it can be recovered separately with the top column of the lower stage, and the ore is dropped with shallow holes. With electric shovel mining, the bottom column ore can be directly loaded and transported in the roadway at this stage. According to the condition of the roof, the actual size of the pillar and the grade of the pillar, the pillars are recovered by different methods. When the ore is rich and the roof is good, the column method is used; the top span is not tolerant, and it is replaced by stone shovel. When the economy is cost-effective, the column method is used; between the two, the column method is used, and the column is used. The richer parts are taken (generally about 1/2), as shown in Figure 1. In order to ensure the proper method of selection, safety, high recovery rate, low depletion rate and good economic effect, the stability of the roof should be carefully investigated and the actual parts, specifications and grades of the retained pillars should be checked and checked ( Sometimes it is necessary to re-sample the test); take appropriate safety measures and supervise the construction due to the experience of full-time safety personnel. Using the above methods and measures, good results are obtained. The recovery rate of the pillars is 42% to 60%, and the column of the rich ore is up to 65%, so that the recovery rate of the ore blocks is 93%, and the depletion rate of the pillars is recovered in 1983. It fell to 24.8%, which is lower than the mine depletion rate of 37.2% in the same year (because there is already a working space to facilitate the selection and recovery). The main material consumption is lower than the first step, but the safety measures and wages have increased. Car Cleaning Brush Set,Wheel Cleaning Brush Set,Wheel And Tire Brush Kit,Detail Brush Kit For Cars Ningbo Longyang Auto Products Co., Ltd. , https://www.zjlongyang-manufacturer.com