Kd-based transport modeling of uranium in groundwater at an acid leaching uranium mine

doi:10.13745/j.esf.sf.2023.2.69

Abstract

Abstract:

Uranium (U) contamination of groundwater at in-situ leaching uranium mines is a global environmental geological problem. Accurately predicting the transport range of U in the groundwater outside the in-situ leaching mining areas is crucial to radiation risk assessment. In this study, the migration range of groundwater U at different production times was quantitatively simulated and predicted by numerical simulation method from an acid in-situ leaching uranium mine. The numerical simulation results showed that the mining activities of in-situ leaching uranium significantly changed the groundwater flow field in the mining area, and depression cones were induced by the high ratio of pumping to injection inside the mining area. On the basis of flow modeling, the transport model of groundwater U without considering adsorption and the retardation transport model based on K_d value were established. According to the groundwater pH of production well and monitoring wells at different distances outside the mining area, different K_d value was assigned by regions. By comparing the simulation results of the two models, it could be found that when considering the adsorption-retardation effect of aqueous medium on groundwater U, the simulation results could be better fitted with the field monitoring data, indicating that the migration of U in groundwater was significantly retarded by the aqueous medium. The U reactive transport model showed that the migration distance and range were reduced by 53% and 41%, respectively. Besides, the model predicted that the migration distance of groundwater U in the mining area was 50 m after 5 years of mining, which was consistent with the monitoring results. It was proven that the numerical simulation method, as an effective tool, could be successfully used to predict the impact of in-situ mining on groundwater environment at the uranium mining site.

Key words: in-situ leaching uranium mine, groundwater environment, numerical simulation, reactive transport

CLC Number:

X523

YANG Bing, MENG Tong, GUO Huaming, LIAN Guoxi, CHEN Shuaiyao, YANG Xi. K_d-based transport modeling of uranium in groundwater at an acid leaching uranium mine[J]. Earth Science Frontiers, 2024, 31(3): 381-391.

Figures/Tables 19

Fig.1 The monitoring well sites of C1-C9 mining areas

Fig.2 The range of models

Table 1 Main input parameters

序号	参数及其单位	数值
1	渗透系数,m/d	5.76
2	垂直各向异性系数	10
3	孔隙度,%	30
4	纵向弥散度,m	2
5	横向弥散度,m	20
6	弹性释水率,m^-1	10^-5

Fig.3 The conceptualization flow rate of production and injection wells

Fig.4 The horizontal spatial discretization

Fig.5 The vertical spatial discretization

Table 2 The pH value of groundwater in different wells

井编号	井类型	位置	pH
KC9502	抽液井	采区内	1.19
6034-1	监测井	采区边界外10 m	2.15
6034-2	监测井	采区边界外30 m	7.38
6034-3	监测井	采区边界外50 m	7.45
6034-4	监测井	采区边界外100 m	7.35
6034-5	监测井	采区边界外150 m	7.27

Fig.6 The Kd Model partition diagram

Table 3 The fitted parameters

序号	观测/拟合日期	(X_obs)_max	(X_obs)_min	n	$1 n ∑ i = 1 n R i 2$	误差/ %	备注
1	2018-11-06	940.65	938.51		0.32	15.15	模型识别
2	2019-05-10	940.84	938.77		0.33	15.95
3	2019-07-21	941.51	938.00	21	0.47	13.48
4	2019-11-17	941.37	939.15		0.46	20.60	模型验证

Table 3 The fitted parameters

序号	观测/拟合日期	(X_obs)_max	(X_obs)_min	n	$1 n ∑ i = 1 n R i 2$	误差/ %	备注
1	2018-11-06	940.65	938.51		0.32	15.15	模型识别
2	2019-05-10	940.84	938.77		0.33	15.95
3	2019-07-21	941.51	938.00	21	0.47	13.48
4	2019-11-17	941.37	939.15		0.46	20.60	模型验证

Table 4 The fitting distribution of absolute mean errors

观测/拟合日期	平均绝对误差范围	观测井个数	各误差范围观测井个数占总数的比例/%
2018-11-06	<0.5 m	18	85.71
	0.5~1 m	3	14.29
	0 m	0	0
2019-05-10	<0.5 m	18	85.71
	0.5~1 m	3	14.29
	0 m	0	0
2019-07-21	<0.5 m	15	71.43
	0.5~1 m	6	28.57
	0 m	0	0
2019-11-17	<0.5 m	13	61.91
	0.5~1 m	7	33.33
	0 m	1	4.76

Fig.7 The fitting of waterhead in monitoring wells in 2018-2019 (A—in November 2018; B—in May 2019; C—in July 2019; D—in November 2019)

Fig.8 The flow field diagram at different simulation time

Fig.9 Diagram of falling funnel in mining area

Fig.10 The fitting results of U concentration distribution in groundwater from C8 mining area

Fig.11 Comparison of simulated and measured groundwater U concentration

Fig.12 The U migration range when the retardation was considered

Fig.13 The fitting results of U(IV) concentration in 6034-1 monitoring well

Fig.14 The distribution of U concentrations in C8 mining area groundwater at the end of the simulation period when the adsorbent retardation was not considered

Fig.15 The distribution of U concentrations in C8 mining area groundwater at the end of the simulation period when the adsorbent retardation was considered

References 33

[1]	张金带, 李子颖, 苏学斌, 等. 核能矿产资源发展战略研究[J]. 中国工程科学, 2019, 21(1): 113-118.
[2]	BRINER W. The toxicity of depleted uranium[J]. International Journal of Environmental Research and Public Health, 2010, 7(1): 303-313. DOI PMID
[3]	CORLIN L, ROCK T, CORDOVA J, et al. Health effects and environmental justice concerns of exposure to uranium in drinking water[J]. Current Environmental Health Reports, 2016, 3(4): 434-442. DOI PMID
[4]	FAA A, GEROSA C, FANNI D, et al. Depleted uranium and human health[J]. Current Medicinal Chemistry, 2018, 25(1): 49-64. DOI PMID
[5]	LAGNEAU V, REGNAULT O, DESCOSTES M. Industrial deployment of reactive transport simulation: an application to uranium in situ recovery[J]. Reviews in Mineralogy and Geochemistry, 2019, 85(1): 499-528.
[6]	孙占学, 刘媛媛, 马文洁, 等. 铀矿区地下水及其生态安全研究进展[J]. 地学前缘, 2014, 21(4): 158-167.
[7]	薛禹群. 中国地下水数值模拟的现状与展望[J]. 高校地质学报, 2010, 16(1): 1-6.
[8]	黄群英. 某砂岩铀矿酸法地浸溶质运移与酸化进程分析[J]. 有色金属(冶炼部分), 2015(6): 50-54.
[9]	张学礼, 徐乐昌. 地浸采铀地下水污染防治措施探讨[J]. 中国人口资源与环境, 2015, 25(增刊2): 360-364.
[10]	POST V, VASSOLO S, TIBERGHIEN C, et al. Weathering and evaporation controls on dissolved uranium concentrations in groundwater: a case study from northern Burundi[J]. Science of the Total Environment, 2017, 607/608: 281-293.
[11]	COUTELOT F M, SEAMAN J C, BAKER M. Uranium(VI) adsorption and surface complexation modeling onto vadose sediments from the Savannah River Site[J]. Environmental Earth Sciences, 2018, 77(4): 148.
[12]	WANG Z M, ZACHARA J M, BOILY J F, et al. Determining individual mineral contributions to U(VI) adsorption in a contaminated aquifer sediment: a fluorescence spectroscopy study[J]. Geochimica et Cosmochimica Acta, 2011, 75(10): 2965-2979.
[13]	JOHNSON R H, TUTU H. Predictive reactive transport modeling at a proposed uranium in situ recovery site with a general data collection guide[J]. Mine Water and the Environment, 2016, 35(3): 369-380.
[14]	BEN SIMON R, THIRY M, SCHMITT J M, et al. Kinetic reactive transport modelling of column tests for uranium in Situ Recovery (ISR) mining[J]. Applied Geochemistry, 2014, 51: 116-129.
[15]	CHENG T, BARNETT M O, RODEN E E, et al. Effects of solid-to-solution ratio on uranium(VI) adsorption and its implications[J]. Environmental Science & Technology, 2006, 40(10): 3243-3247.
[16]	靳强. UVI、Th(IV)、Eu(III)/Am(III)在北山花岗岩和高庙子膨润土上的吸附作用: 温度和腐殖质的效应[D]. 兰州: 兰州大学, 2017.
[17]	DITTRICH T M, REIMUS P W. Uranium transport in a crushed granodiorite: experiments and reactive transport modeling[J]. Journal of Contaminant Hydrology, 2015, 175/176: 44-59.
[18]	ZHU C. A case against K_d-based transport models: natural attenuation at a mill tailings site[J]. Computers & Geosciences, 2003, 29(3): 351-359.
[19]	MILLER A W, RODRIGUEZ D R, HONEYMAN B D. Upscaling sorption/desorption processes in reactive transport models to describe metal/radionuclide transport: a critical review[J]. Environmental Science & Technology, 2010, 44(21): 7996-8007.
[20]	易树平, 马海毅, 郑春苗. 放射性废物处置研究进展[J]. 地球学报, 2011, 32(5): 592-600.
[21]	PAYNE T E, BRENDLER V, OCHS M, et al. Guidelines for thermodynamic sorption modelling in the context of radioactive waste disposal[J]. Environmental Modelling & Software, 2013, 42: 143-156.
[22]	段青梅. 西辽河平原三维地质建模及地下水数值模拟研究[D]. 北京: 中国地质大学(北京), 2006.
[23]	ERÖSS A, CSONDOR K, IZSÁK B, et al. Uranium in groundwater: the importance of hydraulic regime and groundwater flow system’s understanding[J]. Journal of Environmental Radioactivity, 2018, 195: 90-96.
[24]	CURTIS G P, DAVIS J A, NAFTZ D L. Simulation of reactive transport of uranium(VI) in groundwater with variable chemical conditions[J]. Water Resources Research, 2006, 42(4): 336-338.
[25]	DAVIS J A, MEECE D E, KOHLER M, et al. Approaches to surface complexation modeling of Uranium(VI) adsorption on aquifer sediments[J]. Geochimica et Cosmochimica Acta, 2004, 68(18): 3621-3641.
[26]	霍传英, 朱瑾, 魏文慧, 等. 乌鲁木齐河流域北部平原地下水流模拟[J]. 水文地质工程地质, 2009, 36(3): 8-15.
[27]	邵景力, 赵宗壮, 崔亚莉, 等. 华北平原地下水流模拟及地下水资源评价[J]. 资源科学, 2009, 31(3): 361-367.
[28]	徐映雪, 邵景力, 崔亚莉, 等. 银川平原地下水流模拟与地下水资源评价[J]. 水文地质工程地质, 2015, 42(3): 7-12.
[29]	陈昌亮, 肖长来, 赵琳琳, 等. GMS在团结镇地下水流数值模拟中的应用[J]. 节水灌溉, 2014(8): 34-37.
[30]	李玲. 华北平原大型区域地下水流数值模型的构建与应用[D]. 北京: 中国地质大学(北京), 2013.
[31]	BHARGAVA S K, RAM R, POWNCEBY M, et al. A review of acid leaching of uraninite[J]. Hydrometallurgy, 2015, 151: 10-24.
[32]	KAKSONEN A H, LAKANIEMI A M, TUOVINEN O H. Acid and ferric sulfate bioleaching of uranium ores: a review[J]. Journal of Cleaner Production, 2020, 264: 121586.
[33]	DE BOISSEZON H, LEVY L, JAKYMIW C, et al. Modeling uranium and ²²⁶Ra mobility during and after an acidic in situ recovery test (Dulaan Uul, Mongolia)[J]. Journal of Contaminant Hydrology, 2020, 235: 103711.