露天矿掘沟爆破的爆炸水雾场降尘技术研究

由于露天矿掘沟爆破的孔网参数小、炸药单耗高，与正常台阶爆破相比，露天掘沟爆破产生的粉尘浓度更高、扩散速度更快、污染危害更大。传统爆区地表洒水预浸润的方法仅能湿润浅表岩体，并且受爆破飞石、冲击波等有害效应影响，矿用水炮车等远程喷淋降尘方法无法与爆破产尘同步实施。此外，爆破粉尘扩散后的被动治理难度大、效果差。通过Fluent数值模拟研究露天矿掘沟爆破粉尘的生成及初期扩展特性，提出了在掘沟爆区四周布设爆炸水雾场实施就地降尘的技术方案。通过爆炸水袋及爆炸水雾场定型正交试验，确定了爆炸水袋构成及爆炸水雾场的空间尺度及滞空时间等重要降尘技术参数。在白云鄂博铁矿现场降尘试验中按照“四周拦截、同步生成、就地吸附”的原则布设了爆炸水雾场，现场高速摄影分析表明：爆炸水雾场在爆破蘑菇粉尘云形成初期高速生成，对爆破粉尘实施就地拦截和同步吸附，实现了源头降尘的环保目标。测试结果显示：爆破粉尘的质量浓度降低了40%，为低粉尘掘沟爆破和露天矿山绿色开采提供了一种新的环保型技术。

Study on Dust-settling Technology of Explosive Water Mist Field for Trench Blasting in Open-pit Mine

Due to the small network parameters and high explosive consumption in trench blasting of open-pit mine,compared with normal bench blasting,the blasting dust produced by the trench blasting is higher in concentration,faster in diffusion,and more harmful in pollution.The traditional method of surface sprinkling in the blast area can only wet the superficial rock mass.Affected by the harmful effects of blasting flying rocks and shock waves,remote spraying dust reduction methods such as mine water cannons cannot be implemented simultaneously with blasting dust production.In addition,the passive treatment of blasting dust after diffusion is difficult and ineffective.In this paper,Fluent numerical simulation was used to study the formation and initial expansion characteristics of trench blasting dust in open-pit mine,and the technical scheme of in-situ dustfall was proposed by laying explosive water mist field around excavation trench blasting area.Through the orthogonal test of explosive water bag and explosive water mist field,the important dust-settling technical parameters such as the composition of explosive water bag,the spatial scale and the stagnation time of explosive water mist field were determined.Explosive water mist field was set up based on the principle of "surrounding interception,synchronous generation and in-situ adsorption" in the field dustfall test of Bayan Obo Iron Mine.On-site high-speed photography analysis showed that the explosive water mist field was generated at a high speed in the early stage of mushroom dust cloud formation,the blasting dust was intercepted and adsorbed simultaneously to achieve the environmental protection goal of dust reduction at the source.The test results showed that the mass concentration of blasting dust was reduced by 40%,which provided a new environmental protection technology for low dust trench blasting and green mining of open-pit mines.