Research on Ventilation System Optimization and Cooling Technology for Deep Shaft

1. Brief Introduction to the Project
This research achievement was fulfilled jointly by Changchun Gold Research Institute and Xiangxi Gold Mine together under the title of a sub-project of the key national scientific and technology project of the “Ninth Five Year Plan” –“Ventilation System Optimization and Cooling Technology for Deep Shaft”.

According to the features of Xiangxi Gold Mine with deep mining operation, multiple stoping levels, and widely distributed workings, studies on integrated indices of deep mining ventilation system and assessment of heat environment, design and optimization of deep mining ventilation system, and cooling and dust control for deep mining. By these researches, ventilation and cooling technology for deep mining with Chinese characteristics have been developed. Breaking through the traditional shaft ventilation mode, this project uses multistage stations in the sub-sections in deep mine. The major technology features are: the whole ventilation system was divided into different sections according to the underground conditions of the actual operation,with each section consisting a relatively independent sub-system and connecting with the downcast and upcast of the ventilation system. The airflow of each section may be controlled according to the operational requirements, avioding short-current of the foul air, which made the whole system operate reasonably. Meanwhile, by the project, the new technology of integrated cooling is created, where colling is dominated by ventilation, combined with the pre-cooled downcast air from the low temperature rock as well as wet dust control. This technology has the features of low in engineering cost, high effect in cooling and convenient for applications in the mines with shaft.

2.Major Techno-economical Indices and Benefits
A ventilation system with reasonable network structure and complete controlling facilities was built in the underground of Xiangxi Gold Mine, which provided the key technology for heat hazard control in deep mining, the environment in its major deep workings reached the national standards, with its integrated evaluation index for deep mine ventilation system excesses 70％, up to 84.78％.

Based on the principals of reasonable combination and distribution of shaft and drift according to their functions, optimization and engineering of the deep mine ventilation system were carried out, by which more than 5 million yuan of engineering cost was saved and significant economic benefits obtained.

Applying this research achievement, the underground working environment in Xiangxi Gold Mine was greatly improved and occupational diseases and accidents decreased.

3. Comments and Application Prospects
The research result, either in theory or in practical application, is advanced in both domestic and international standards. 32 operational levels and 120 working faces constituted one of the world's most complicated mine ventilation system --- a first case of deep mine ventilation system in China, which system has the advantages of reasonable structure to prevent foul air from short-current, easy airflow control, and low cost operation, providing a new channel to solve deep mine ventilation problems. By combination of the technology of low temperature rock effect and its ventilation cooling technologies, the comprehensive evaluation index of the ventilation system was greatly improved.

A patent has been awarded to the quantitative controllable gas sampler and a comprehensive waterproof rock thermometer developed during the research process.