Integrated Research on the Mining of Complicated Deposit in Xincheng Gold Mine

1. Brief Introduction
This achievement was made through the key national scientific and technology project of “the Ninth Five Year Plan” jointly by Changchun Gold Research Institute, Shandong Xincheng Gold Mine, Beijing Science and Technology University, Northeast University and Changsha Mines Institute. Based on the complicated mining conditions of Xincheng Gold Mine, panel cut-and-fill mining method of connntinous upwards stoping with high sublevels was creatively applied in its -250m level, which divided the 8 stopes of the panel into two groups with 3 stopes of each group being arranged in triangle, forming pressure free arch which made the distribution of stress surrounding the panel reasonable. By continuous stoping, secondary stoping for pillar recovery may be avioded, enhancing the panel output and mining efficiency, and lowering down mining loss and delution. When using this mechanized horizontal mining, the sublevel height of each stoping was increased from traditional 2.2-3.4m home and abroad to some 4.3m, which improved mining efficiency, cutting filling cost, lowering down mining loss and delution. By applying a test technology with full temperature compensation and taking account of non-linear stress in rock mass, site determination of the ground stress in the mine area was carried out. Through 3D stresse distributions obtained from 17 measuring points in 4 levels, the model of stress distribution in the mine area was established. According to aerodynamic fluid technique, fluidizing jet nozzle for compressed air was invented, which enabled the discharging density of filling sand to increase to 72%-78% from a normal value of 65%.

2. Techno-economic Indices and Benifits
By using this achievement, the integrated panel production capacity reached to 282.4 t/d ,the total loss lowered down to 3.76% from previous 7.2％, the delution decreased to 5.15% from previous 7.3%. The average profit during the testing period was 11,476,700 yuan, and prospecting application profits 191,699,300 yuan.

3. Comments and Application Prospects
This mining method is safe in operation, high in efficiency and outstanding in economic benefit. If it is applied to other gold mines and metal mines with similar deposit conditions, great social benefits would be generated. Therefore, this research not only has positive effect on the development of the whole gold industry, but also made contributions to the development and technical progress of mining. This project won the special prize in advancement of science and technology of gold industry awarded by former National Economic and Trade Committee and the second prize for science and technology progress awarded by the National Committee of Science.