Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, SK S7N 5E2, Canada.
Department of Civil, Geological and Environmental Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, SK S7N 5A9, Canada.
Sci Total Environ. 2017 Dec 15;605-606:915-928. doi: 10.1016/j.scitotenv.2017.05.253. Epub 2017 Jul 6.
The origin, distribution and leaching of nitrate (NO) from coal waste rock dumps in the Elk Valley, British Columbia, Canada were defined using chemical and NO isotope analyses (δN- and δO-NO) of solids samples of pre- and post-blast waste rock and from thick (up to 180m) unsaturated waste rock dump profiles constructed between 1982 and 2012 as well as water samples collected from a rock drain located at the base of one dump and effluent from humidity cell (HC) and leach pad (LP) tests on waste rock. δN- and δO-NO values and NO concentrations of waste rock and rock drain waters confirmed the source of NO in the waste rock to be explosives and that limited to no denitrification occurs in the dump. The average mass of N released during blasting was estimated to be about 3-6% of the N in the explosives. NO concentrations in the fresh-blast waste rock and recently placed waste rock used for the HC and LP experiments were highly variable, ranging from below detection to 241mg/kg. The mean and median concentrations of these samples ranged from 10-30mg/kg. In this range of concentrations, the initial aqueous concentration of fresh-blasted waste rock could range from approximately 200-600mg NO-N/L. Flushing of NO from the HCs, LPs and a deep field profile was simulated using a scale dependent leaching efficiency (f) where f ranged from 5-15% for HCs, to 35-80% for the LPs, to 80-90% for the field profile. Our findings show aqueous phase NO from blasting residuals is present at highly variable initial concentrations in waste rock and the majority of this NO (>75%) should be flushed by recharging water during displacement of the first stored water volume.
利用化学分析和氮同位素（δN- 和 δO-NO）分析对加拿大不列颠哥伦比亚省埃尔克谷（Elk Valley）的煤矸石堆中硝酸盐（NO）的来源、分布和淋滤情况进行了定义，分析对象包括爆破前后矸石的固体样品，以及 1982 年至 2012 年间构建的厚达 180 米的非饱和矸石堆剖面，还包括从一个矸石堆底部的岩渠和湿度计（HC）和淋滤垫（LP）试验流出的废水。矸石和岩渠水中的 δN- 和 δO-NO 值和 NO 浓度证实了矸石中 NO 的来源是炸药，且矸石堆中几乎不存在反硝化作用。爆破过程中释放的 N 质量平均约占炸药中 N 的 3-6%。HC 和 LP 试验所用新鲜爆破矸石和最近放置的矸石中的 NO 浓度变化很大，从低于检测下限到 241mg/kg 不等。这些样品的平均值和中位数浓度范围为 10-30mg/kg。在这个浓度范围内，新鲜爆破矸石的初始水溶液浓度约为 200-600mg NO-N/L。利用与尺度相关的淋滤效率（f）模拟了 HC、LP 和深剖面中从 HC、LP 和深剖面中冲洗 NO 的过程，f 值范围分别为 HC 为 5-15%，LP 为 35-80%，深剖面为 80-90%。我们的研究结果表明，爆破残留的水相 NO 以高度可变的初始浓度存在于矸石中，其中大部分（>75%）NO 应该在第一次储水体积被置换时通过补充水冲洗掉。
