Previous studies on blast fumes (carbon monoxide and nitrogen dioxide) clearance and workplace reentry time have overlooked the effects of toxic gases trapped in the muck pile. The currently available models for calculating the mine reentry times assume that all post-blast fumes are emitted upon detonation. However, recent studies reported that as much as 60 to 70% [1–5] of the fumes or gases produced during an underground development blasting could remain trapped in the adjacent rock mass or in the muck pile. Trapped fumes are slowly released [1–5], and when disturbed, high concentrations are released, representing a possible risk during the loading and transportation of the muck pile. In this study, mathematical models were developed using computational fluid dynamics to understand the behavior of the trapped fumes and their effect on mine reentry time. The three scenarios considered for this study include (i) gas emission source with no muck pile volume, (ii) gas emission source with non-porous muck pile volume, and (iii) gas emission source with porous muck pile volume. The estimated reentry times in all three scenarios were compared to see how porous media affects dilution time. It was observed that scenario 3, with fumes trapped in the muck pile, took a significantly longer clearance time (more than double) as compared to scenarios 1 and 2.

以前关于爆炸烟雾（一氧化碳和二氧化氮）清除和工作场所再入时间的研究忽略了被困在渣土堆中的有毒气体的影响。当前可用的用于计算矿井再入时间的模型假设所有爆炸后的烟雾在爆炸时排放。然而，最近的研究报告称，在地下开发爆破过程中产生的烟雾或气体中，多达 60% 到 70% [1-5] 可能仍被困在邻近的岩体或渣土堆中。截留的烟雾会缓慢释放[1-5]，当受到干扰时会释放出高浓度的烟雾，这意味着在渣土堆的装载和运输过程中可能存在风险。在这项研究中，使用计算流体动力学开发了数学模型，以了解捕获烟雾的行为及其对矿井再入时间的影响。本研究考虑的三种情景包括 (i) 无渣堆体积的气体排放源，(ii) 无孔渣堆体积的气体排放源，以及 (iii) 带有多孔渣堆体积的气体排放源。比较了所有三种情况下估计的再入时间，以了解多孔介质如何影响稀释时间。据观察，与场景 1 和 2 相比，场景 3（烟尘被困在渣土堆中）需要更长的清除时间（超过两倍）。(iii) 具有多孔渣土体积的气体排放源。比较了所有三种情况下估计的再入时间，以了解多孔介质如何影响稀释时间。据观察，与场景 1 和 2 相比，场景 3（烟尘被困在渣土堆中）需要更长的清除时间（超过两倍）。(iii) 具有多孔渣土体积的气体排放源。比较了所有三种情况下估计的再入时间，以了解多孔介质如何影响稀释时间。据观察，与场景 1 和 2 相比，场景 3（烟尘被困在渣土堆中）需要更长的清除时间（超过两倍）。