深凹露天矿流场分布及粉尘污染预测

A large number of dust is produced by some process such as perforation, blasting, loading and transportation in open-pit mine .Dust remain in stope for a long time because the air convection between mine internal and external almost stops and the complex circulation structure brings on a low wind speed ,especially under the condition of foggy and static wind inversion in the night, as for the deep open pit mine with more than 100m mined depth.. The dust is not only threaten the workers' health and safety, but also affect the mining production when in serious condition . In order to ensure mine safety production and protect the workers' health, It is necessary to evaluate the air quality of stope timely and accurately as well as good pollution forecast by studying the wind field structure of stope , dust diffusion and settlement law.. The method of multiphase flow theory and numerical analysis methods are applied to field test, theory analysis and computer simulation, the structure of the air flow at the stope has been investigated to build and solve models of dust diffusion and dust pollution prediction. From the models, the dust pollution level can be predicted to provide theoretical basis and experimental data for rational arrangement and organization of production, and the development of the discipline of deep open pit ventilation also be promoted.

露天矿内穿孔、爆破、铲装、运输等采矿作业均会产生大量粉尘。对于采深超过100m的深凹露天矿来说，由于存在复环流结构，坑内风速很低，特别在夜晚、多雾、静风逆温条件下，矿内外空气对流几乎停止，粉尘长时间滞留在采场内。这些粉尘不仅威胁职工健康和行车安全，严重时还会导致采矿生产无法正常进行。因此为保证矿山安全生产及保护职工健康，从分析采场风场及温度场结构入手，研究粉尘扩散及沉降规律，及时、准确评价采场大气质量，做好污染预测预报是非常必要的。.本项目通过现场测试、理论分析及计算机模拟研究，运用多相流理论及数值分析方法，对采场风流结构和温度场分布进行研究，建立粉尘扩散及污染预报模型并进行求解，预测粉尘污染程度，为合理安排和组织生产，控制采场粉尘提供理论依据和实验数据，并可以促进深凹露天矿通风学科的发展。

露天采矿进入深凹开采阶段后，采场内风速随着采深加大越来越小，自然通风效果也越来越差，致使采场内粉尘浓度高，严重威胁着采矿作业人员的健康。目前关于深凹露天矿内流场分布、自然通风效果及粉尘污染预测等诸多问题尚需深入研究。本项目紧密围绕深凹露天矿流场分布及粉尘污染预测问题，采用理论分析、现场试验、相似模拟实验及数值模拟相结合的方法，系统研究深凹露天矿流场分布及影响因素、温度场分布及演变规律、开采各环节粉尘产尘量、爆破粉尘扩散规律、采场粉尘浓度预测及自然通风效果等有关内容。.基于现场实测和理论分析的方法，获得试验矿山爆破作业、汽车运输等主要作业环节产尘强度及其贡献率；揭示了深凹露天矿爆破粉尘污染时空分布规律，建立了采场粉尘浓度预测模型。.通过相似模拟及数值模拟实验，研究背风边坡角度、深度及长轴尺寸三个因素对复环流形态分布的影响，获得上述因素对复环流形态分布影响的重要度排序，依次是采深、边坡角及长轴尺寸，并首次提出露天矿复环流发展情况综合性评价参数K，对现有单因素评价参数进行了补充和完善。.采用现场实测及数值模拟方法，揭示了试验矿山采场流场、温度场分布及演变规律。获得试验矿山大气稳定度参数m的取值范围。.采用理论分析、相似模拟实验和数值模拟相结合的方法，研究采场内通风换气效果与风速关系，建立露天矿通风换气系数计算模型。.本课题研究成果不仅可以指导矿山根据气象条件合理组织生产、利用自然通风加强粉尘排除，改善采场作业环境，而且对于深凹露天矿人工强制通风措施提供数据和理论依据，补充完善了深凹露天矿通风基础理论。