The length of the open-pit working line not only has a direct relationship with the production stripping ratio, but also has an impact on the distance of the open-pit and the amount of capital construction, thus affecting the economic benefit of the entire open-pit. At present, the mining of coal seams in large open-pit coal mines mainly uses the semi-continuous process of single-bucket excavation-truck - semi-fixed crusher - belt conveyor, and the length of the working line plays a crucial role in the system. Compared with other mobile crusher semi-continuous process, the longer the working line, the more transportation costs are saved, and the higher the efficiency of its single-bucket excavator. In each link of the semi-continuous process, the equipment is fixed, that is, the annual production capacity of the whole system is certain. When the working line is short, the production capacity of the system will be affected by frequent shifting of the tape; When the working line is long, if the capacity of the feeder breaker semi-continuous process system is less than the advancing speed of the lower step, the inner dump can not follow up, reducing the volume of the inner dump, so the reasonable working line length has a great impact on the capacity of the feeder breaker semi-continuous process system. 1 Principle of determining the length of the working line
The working line length is determined by comparing the efficiency of the single bucket excavator in the feeder breaker semi-continuous process with that of the other moving crusher semi-continuous process. For the same single-bucket excavator, complete the same workload, the same working time, by comparing the non-working time of the two process systems, find the suitable working line length for the application of the semi-continuous process of feeder breaker. The introduction of the feeder breaker is to maximize the capacity of the single bucket excavator, if the non-working time of the semi-continuous process of the feeder breaker is more than the non-working time of the continuous process of the other mobile crusher, it is not suitable to use the feeder breaker semi-continuous process 4.
2 Non-working hours of 2 processes
2.1 Feeder breaker Non-working time of semi-continuous process
The same amount of work in the same mine area means the same number of working strips, minus the same amount of non-working time, compared to the other feeder breaker semi-continuous process: The walking time of the single-bucket excavator, the time of the opening help incision, the time of the finishing work plate and the failure time of the single-bucket mining, etc., in order to simplify the research, the different non-working time only considers the internal factors of the system, and the maintenance time of other equipment is not considered. Therefore, compared with the semi-continuous process of the mobile crusher, the time of the single-bucket excavator is not considered. The non-working time of the semi-continuous process includes: the travel time of the feeder breaker on the working surface and the shift time of the belt conveyor. The travel time of the feeder breaker is mainly determined by the frequency of the feeder breaker, the length of the working line and the number of mining zones.
By analyzing the non-working time of the semi-continuous process of the feeder breaker and the semi-continuous process of other mobile crusher, and comparing the non-working time of the two processes, the relationship between the efficiency of the semi-continuous process of the feeder breaker and the semi-continuous process of other mobile crusher is obtained, and the relationship between the efficiency of the semi-continuous process of the feeder breaker and the reasonable minimum working line length is obtained. To provide the basis for the application of the semi-continuous process of feeder breaker.