Detail Extended Abstract

SIGNS OF ACID MINE DRAINAGE AND DISTRIBUTION OF HEAVY METAL INTO THE ENVIRONMENT AT BAN PHUC NICKEL MINE

MeetingVIWC2026
TopicOS3: Water Environment and Mining
AuthorPham Van Chung | Nguyen Van Pho | Nguyen Thi Thuc Anh
OrganizationHanoi University of Natural Resources and Environment | Vietnam Geochemistry Association | Vietnam Geochemistry Association
ID2022.1670001964

Content

  1. INTRODUCTION
Environmental pollution in mineral mines is a very serious problem, in which metallic mineral deposits have mineral compositions including sulfides, which, when oxidized, will form acid mine drainage and disperse metals, seriously pollute the environment. Mineral activities are the main cause of the formation of acid mine drainage and the dispersion of heavy metals into the environment [3,4,5]. The way to disperse heavy metals into the environment is mainly surface water, then into the soil environment, groundwater environment. The process of polluting can take place for hundreds of years, it does not only take place during mining but after the end of mining. Ban Phuc nickel mine is one of the typical nickel sulfide mines in Vietnam, the main mineral compositions are: pyrotin, chalcopyrite, penlandite, ... the mine has many potential risks forming acid mine drainage waste streams and metal heavy on the environment. However, Ban Phuc nickel mine has done a good job of protecting the environment, so the pollution is effectively controlled.
  1. RESEARCH METHODS
II.1. Methods of synthesizing and analyzing documents Research documents on geology, geochemistry and related environment are synthesized, analyzed, and selected by the authors as a basis and research orientation. The research works of many authors are important sources of literature. In this work, the author has collected materials on geology, lithology, geochemistry, environmental impact assessment reports, environmental monitoring documents at Ban Phuc Nickel mine area. II.2. Field survey method Field survey is a very effective and indispensable method when studying geology and geochemistry of the environment. During the research process, the authors conducted field surveys to collect information about factors that can affect the environment and signs of environmental pollution in the study area. During the fieldwork, samples of primary and secondary ores, surrounding rock samples, bottom mud samples, water samples, tail ore samples will be taken, and environmental indicators such as pH, Eh, and temperature will be measured. to assess the environmental quality of mineral deposits and surrounding areas. II.4. Atomic absorption method AAS Atomic Absorption Spectrophotometric (AAS) method is a very sensitive analytical technique to measure the concentration and content of elements. Atoms are in a free state in the form of clouds of atomic vapors, where they absorb and radiate energy. Each atom absorbs only certain radiations that correspond to the radiations they can give off during their emission. When atoms receive energy, they move to a higher energy level called an excited state. That process is called the process of absorbing the energy of a free atom in the vapor state and generating the spectrum of that atom. The spectrum produced in this process is called the atomic absorption spectrum. The AAS atomic absorption spectroscopy method allows the determination of almost all the major elements (except P) that can be determined and the detection limits of Na, K and Ca are extremely low. In this study, we use atomic adsorption method to determine the content of heavy metal elements present in water and soil environment. The samples were conducted at the Center for Analysis of Geological Experiments using a PinAAcle 900T atomic absorption spectrometer, manufactured by PerkinElmer of the US in 2019. III. RESULTS AND DISCUSSION III.1. Overview of Ban Phuc Nickel Mine Ban Phuc Nickel Mine is located in Muong Khoa Commune, Bac Yen District, Son La Province. The mine is located right next to Highway 37 and about 2km from the Da River. The terrain is high, steep, strongly dissected, and dangerous. The lowest altitude is 100m, the highest is 1969m, usually +700m. In the Ban Phuc Nickel mine, there is Phuc stream flowing through the selection plant area and Dam stream flowing through the tailings lake area, these two streams flow into Khoa stream before flowing into the Da river. Mineral composition mainly includes pyrotin: 66 - 90%, pentlandite: 3 - 35%, chalcopyrite: 5 - 16%. Chemical composition of sulfide Nickel ore - Condensed copper with an average content of 1.44% Ni; 0.69% Cu; 0.05% Co; 25 ppb Au; 64 ppb Pt; 30 ppb Pd; 14.42% S; 2.28% Mg; 26.7% Fe [1,2]. Ban Phuc nickel mine has finished exploiting the dense ore body and is conducting exploration to exploit the diffuse ore body. In the mine area, has been built factory nickel ore flotation III.2. Environmental characteristics of surface water Pollution of surface water is one of the common signs appearing in mineral deposits. For nickel-copper sulfide mineral deposits, the surface water environment often has low pH and high heavy metal content. To assess the current state of the surface water environment of the Ban Phuc nickel mine, we took water samples from streams and quickly measured environmental indicators, sent for analysis to determine the content of heavy metals. Figure 1: Water sampling map of Ban Phuc Nickel mine area. Table 1. Analytical results of surface water samples at Ban Phuc nickel mine area
  No   Model number Coordinate system VN2000 Thành phần (mg/l)
X Y pH Eh (mV) T Cu Ni Fe As Cd Total
1 NBP.01 2343814 429071 4,2 450 32 1,223 1,578 5,4 0,0106 0,0032 8,2148
2 NBP.02 2343738 429151 3,9 560 32 1,425 1,778 5,2 0,0102 0,0034 8,4166
3 NBP.03 2343642 429262 4,1 475 32 1,235 1,678 5,6 0,011 0,0031 8,5271
4 NBP.04 2343526 429376 4,3 482 32 1,239 1,612 5,2 0,0116 0,0035 8,0661
5 NBP.05 2343420 429487 4,2 467 32 1,258 1,571 5,8 0,0112 0,0034 8,6436
6 NBP.06 2343309 429537 4,1 454 32 1,346 1,672 5,2 0,0104 0,0036 8,232
7 NBP.07 2343219 429614 4,4 485 32 1,313 1,634 5,3 0,0126 0,0033 8,2629
8 NBP.08 2343386 429675 3,8 538 31 1,449 1,598 5,3 0,0112 0,0032 8,3614
9 NBP.09 2344219 430338 3,6 547 31 1,623 1,545 5,6 0,0102 0,0023 8,7805
10 NBP.10 2344079 430487 3,7 638 31 1,682 1,605 5,5 0,0112 0,0031 8,8013
11 NBP.11 2343873 430370 4,6 372 31 1,92 1,705 5,8 0,0114 0,0034 9,4398
12 NBP.12 2343693 430148 4,9 335 30 1,97 1,813 5,7 0,0102 0,0035 9,4967
13 NBP.13 2344002 430706 3,8 645 31 1,98 1,856 5,4 0,011 0,0037 9,2507
14 NBP.14 2343902 430698 4,1 678 30 1,87 1,801 4,5 0,0048 0,0019 8,1777
15 NBP.15 2343785 430619 4,2 656 30 0,612 0,836 3,3 0,0024 0,0014 4,7518
16 NBP.16 2343568 430648 4,1 634 30 1,523 1,645 4,3 0,0048 0,0021 7,4749
17 NBP.17 2343346 430772 5,2 435 30 1,282 1,405 4,2 0,0058 0,0011 6,8939
18 NBP.29 2344354 430156 3,8 537 34 0,262 0,246 1,2 0,0004 0,0003 1,7087
19 NBP.30 2344507 429989 3,9 538 30 0,122 0,143 1,5 0,0002 0,0006 1,7658
20 NBP.31 2344896 429960 6,7 255 30 1,082 1,105 3,2 0,0072 0,0014 5,3956
21 NBP.32 2345277 429995 6,7 213 30 1,082 1,105 3,4 0,0064 0,0024 5,5958
22 NBP.33 2344584 429550 4,3 521 30 0,736 0,846 3,7 0,0054 0,0017 5,2891
23 NBP.38 2344502 429307 3,9 542 30 0,687 0,812 3,5 0,0042 0,0013 5,0045
24 NBP.39 2344328 429159 4,5 322 30 0,723 0,887 3,5 0,0044 0,0015 5,1159
25 NBP.40 2344198 428952 5,4 298 30 1,223 1,578 5,4 0,0106 0,0032 8,2148
26 NBP.41 2344023 429087 5,1 308 30 1,425 1,778 5,2 0,0102 0,0034 8,4166
QCVN 08-MT:2015/BTNMT cột B1 5,5 - 9     0,5 0,1 1,5 0,05 0,01  
Measurement results of pH, Eh and analysis of heavy metal content showed that surface water in Ban Phuc nickel mine area showed signs of pollution, namely low pH, high content of heavy metals. To simulate the results of measuring pH and content of heavy metals in surface water of Ban Phuc nickel mine, we use simulation software acrgis as follows: Figure 2: Simulation diagram of pH on streams in Ban Phuc nickel mine area Figure 3: Simulation diagram of heavy metal concentrations in surface water Ban Phuc nickel mine III.3. Đặc điểm môi trường đất Figure 4: Soil sampling map of Ban Phuc Nickel mine area Table 2. Analysis results of soil samples in Ban Phuc Nickel mine area
  No   Model number Coordinate system VN2000 Ingredients (mg/kg dry soil)
X Y Cu Ni Fe As Cd Total
1 SBP.01 429140 2343910 142 187 34514 8,5 1,72 34853,22
2 SBP.02 429225 2343836 133 202 36842 6,4 1,04 37184,44
3 SBP.03 429129 2343697 145 231 42047 9,2 1,56 42433,76
4 SBP.04 429298 2343599 153 214 40232 9,7 1,94 40610,64
5 SBP.05 429420 2343504 189 223 41824 8,1 1,87 42245,97
6 SBP.06 429461 2343437 217 243 42124 11,1 1,76 42596,86
7 SBP.07 429574 2343264 223 256 45678 10,3 2,12 46169,42
8 SBP.08 429709 2343203 236 253 44389 10,5 2,23 44890,73
9 SBP.10 429769 2343095 242 261 43945 11,2 2,23 44461,43
10 SBP.11 429618 2343103 259 267 44715 11,8 2,18 45254,98
11 SBP.17 429069 2344219 143 166 36114 6,4 1,05 36430,45
12 SBP.25 429172 2344470 143 164 37245 6,4 1,05 37559,45
13 SBP.26 429489 2344544 152 167 37376 6,7 1,02 37702,72
14 SBP.30 429672 2344764 156 172 37745 6,5 1,04 38080,54
15 SBP.31 429876 2344666 174 183 38912 6,2 1,12 39276,32
16 SBP.32 429994 2344566 194 213 40125 9,3 2,12 40543,42
17 SBP.33 430086 2344441 213 242 45641 9,8 2,23 46108,03
18 SBP.34 430283 2344236 245 276 47463 11,3 2,25 47997,55
19 SBP.35 430531 2344103 248 281 47852 11,6 2,31 48394,91
20 SBP.36 430609 2343994 253 286 48212 11,8 2,26 48765,06
21 SBP.37 430676 2343796 264 282 47642 11,1 2,14 48201,24
22 SBP.38 430613 2343655 275 292 48523 12,1 2,34 49104,44
23 SBP.39 430777 2343420 242 283 47878 11,7 2,33 48417,03
24 SBP.41 430042 2345073 184 189 38945 6,2 1,12 39325,32
25 SBP.42 430346 2344581 111 117 29263 5,5 1,03 29497,53
26 SBP.45 430710 2344071 216 251 45647 9,8 2,23 46126,03
QCVN 03-MT:2015/BTNMT 150 - - 20 3  
From the research results on the content of heavy metal elements in the soil environment of Ban Phuc nickel mine area, heavy metal elements are found in the areas of tailing ore waste lake, ore storage yard, high industrial yard. To simulate the dispersion of heavy metals into the soil environment, we use arcgis software as follows: Figure 5. Simulation diagram of heavy metal content in soil environment Ban Phuc nickel mine III.4. Forecast of potential environmental problems III.4.1. Environmental pollution due to tailing ore discharge lake The tailing ore waste lake is an area of tailed ore that has a lot of potential for environmental pollution because the composition of tail ore contains secondary sulfide minerals, so it will be oxidized to form mine acid discharge and disperse metals heavy. Figure 6. Ban Phuc nickel mine tailings tailings pond III.4.2. Pollution due to solid waste In the areas of waste dumps, dumps, and industrial yards, there is always the potential for environmental pollution because the composition of the waste rock contains sulfide minerals, ores left in the dumps and industrial yards. Sulfide minerals will be oxidized and produce mine acids and heavy metals. Rainwater runoff will carry heavy metals into the environment.
Figure 7. Ban Phuc nickel mine waste rock Figure 8. Oxidized ore at the old storage yard of Ban Phuc nickel mine
III.5. Proposing solutions to reduce environmental pollution Stemming from the causes of environmental pollution and potential risks of environmental pollution in the future, we propose some solutions to reduce environmental pollution at Ban Phuc nickel mine as follows: For tailings ore tailing ponds, the dam must first be kept safe to avoid dam failure by regularly checking the dam\'s safety. Carrying out pumping to cover the surface of mud after mining. Periodic monitoring of the waste lake environment to monitor the environment. For underground wastewater, rainwater flowing through industrial yards, intra-mine transportation roads, ore storage yards, it is necessary to build water collection systems to concentrate treatment before being discharged into the environment. - For solid waste in the form of piles generated in the process of mining, it is necessary to plan and design the landfill to be built with walls of acid-neutralizing materials.
  1. CONCLUDE
The research results in surface water and soil in the Ban Phuc nickel mine area showed that the pH in surface water was low, the content of heavy metals was high, and in some samples exceeded the permissible standards. The sulfide minerals in the tailing ore, solid waste, when weathered, will produce acid mine discharge and disperse heavy metals into the environment. To minimize environmental pollution, it is necessary to carry out synchronous solutions to prevent mine acid discharge and collect and treat before discharging into the environment.
  1. THANK YOU
We would like to thank the management of the project \"Research and build models of heavy metal dispersion in the environment in areas with sulfur minerals\", code: TNMT.2021.562.01 of the \"Development Program\" basic science in the field of Earth Science according to Decision No. 562/QD-TTg dated April 25, 2017 of the Prime Minister. Program number: 562” provided us with the research data.
  1. REFERENCES
[1]. Dinh Huu Minh (2003). \"Geological structure and characteristics of Nickel sulfide ore mineralization - Ban Phuc Son La copper mine\". Doctoral Thesis - Library of Mining and Geology University, Hanoi. [2] Dinh Huu Minh, Nguyen Ngoc Hai and al (2006). “Report of Nickel Mine Exploration - Ban Phuc”. Geospatial Information Center, Hanoi. [3]. Nguyen Van Pho, Pham Tich Xuan (2011). \"Geo-environmental model of mineral mines and general significance in assessing the environmental impact of mining\". Journal of Earth Sciences, No. 33(4) 661-668. [4]. Nguyen Van Pho (2013) “Vietnam humid tropical weathering”. Publishing House of Natural Science and Technology. [5]. Plumlee G.S: The environmental geology of mineral deposits, in Plumlee, G.S., and Logsdon, M.J., eds., Environmental Geochemistry of Mineral Deposits, Part A: Processes, Techniques, and Health Issues: Reviews in Economic Geology, v. 6A, (1999) p. 71-116.

acid mine drainage, heavy metal pollution, Ban Phuc Nickel mine