## 2 The Method of Blasting Effect Evaluation  
### Evaluation Parameters  
Bench blasting performance has some undesirable impacts, such as vibration and back break; therefore, effect evaluation for bench blasting is quite complicated. The rationality of the established method for evaluating blasting effect is related to the fact that it could reflect the blasting effect correctly, and then provide information for optimizing the blast design.  
In bench blast design, security issues are the key factors to be considered. In bench blasting performance, fly-rock is one of the most important causes of accidents, and blasting vibration is particularly harmful to buildings; therefore, the blasting safety evaluation is basic for the whole blasting effect evaluation. Blasting quality is the purpose of blast design. Blasting quality can directly affect construction efficiency, which would affect the subsequent operations, such as loading, hauling and crushing. Under the premise of ensuring blasting safety, optimizing the blast design is important for maximizing the blasting efficiency. Additionally, in bench blasting performance, energy and economic waste usually exist; therefore, the effective measures to reduce blasting costs and improve economic efficiency should be taken, which is the main factor that a blast design needs to be considered. Therefore, in this study, the blasting effect is evaluated from three aspects: blasting safety, quality and cost--11 typical parameters are chosen and are divided into these three classes. Eleven typical parameters are used to describe the effect of bench blasting. Fly-rock: the shorter the distance of flying stone, the less harm caused by blasting. Vibration: the smaller the peak value of blasting vibration, the smaller the harm caused by vibration. Boulder yield: the block size meets the engineering requirements, and the block rate is low. Muck pile height: the blasting pile is concentrated and has certain looseness, which should not be too high or too low, so as to meet the requirements of efficient shoveling of equipment. Forward distance: using the slag body reserved from the previous blasting, the forward striking distance of blasting pile body is controlled to make the blasted rock mass collide with the residual slag body, reduce the block rate and improve the energy utilization rate. Back break under excavation, this will cause processing delay or idling, reduce productivity and waste money. Depth of lateral posterior sulcus: in order to avoid the slope collapse, the back gully should be built at an appropriate place outside the slope to remove the water. Bench smoothness: high step flatness is conducive to improve the efficiency of the next drilling and shoveling transportation. Explosive unit consumption: reasonable explosive unit consumption is conducive to improving energy utilization and saving cost. Blasted volume per meter: the higher the blasting quantity, the better the blasting effect. Auxiliary materials: lowering the consumption of auxiliary materials but maintaining the same blasting effect, meaning the cost is lower. Finally, the comprehensive evaluation is given. The parameter classifications are listed in Table 1.