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Design, construction and management of tailings storage facilities for surface disposal in China: Case studies of failures


Abstract and Figures

Rapid development of China's economy demands for more mineral resources. At the same time, a vast quantity of mine tailings, as the waste byproduct of mining and mineral processing, is being produced in huge proportions. Tailings impoundments play an important role in the practical surface disposal of these large quantities of mining waste. Historically, tailings were relatively small in quantity and had no commercial value, thus little attention was paid to their disposal. The tailings were preferably discharged near the mines and few tailings storage facilities were constructed in mainland China. This situation has significantly changed since 2000, because the Chinese economy is growing rapidly and Chinese regulations and legislation require that tailings disposal systems must be ready before the mining operation begins. Consequently, data up to 2008 shows that more than 12 000 tailings storage facilities have been built in China. This paper reviews the history of tailings disposal in China, discusses three cases of tailings dam failures and explores failure mechanisms, and the procedures commonly used in China for planning, design, construction and management of tailings impoundments. This paper also discusses the current situation, shortcomings and key weaknesses, as well as future development trends for tailings storage facilities in China.
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Waste Management & Research
31(1) 106 –112
© The Author(s) 2013
Reprints and permission:
DOI: 10.1177/0734242X12462281
China is currently one of the world leaders in both exploitation
and consumption of mineral resources. Billions of tonnes of
metal ores are mined in China every year, and billion of tonnes of
tailings and wastes as byproducts are disposed of on the ground.
In the early 1980s, tailings were considered as residue with no
commercial value. Most of the small and medium-size mines
directly discharged their tailings into the local valleys or rivers
close to the mines. Consequently the mining industry developed
a poor reputation for waste disposal management. With the
enhancement of environmental protection awareness, both regu-
lations and legislation were successively promulgated and imple-
mented in the early 1990s, requiring mine owners to build tailings
disposal facilities and water treatment systems before any com-
mercial mining may commence. The impoundments are regarded
as a major part of the mining facilities and were used to store
tailings and waste water from mineral processing (Kanagasbai
1980; Kwak et al., 2005). With the growth of the mining industry
in China, many tailings impoundments have been built and more
are planned. Up to now, China has achieved success in tailings
disposal and has greatly improved its environmental performance
in relation to mining activities. The authors consider that this
experience and the lessons learned by China’s mine operators
may also be useful to mine operators in other countries. Herein,
the history of tailings disposal in China is discussed and three
examples of tailings dam failures in China are analysed in detail.
The procedures of planning, design and construction of tailings
Design, construction and management
of tailings storage facilities for
surface disposal in China: case
studies of failures
Zuoan Wei1,3,4, Guangzhi Yin1,3,4, J G Wang2, Ling Wan1,4
and Guangzhi Li1,4
Rapid development of China’s economy demands for more mineral resources. At the same time, a vast quantity of mine tailings,
as the waste byproduct of mining and mineral processing, is being produced in huge proportions. Tailings impoundments
play an important role in the practical surface disposal of these large quantities of mining waste. Historically, tailings
were relatively small in quantity and had no commercial value, thus little attention was paid to their disposal. The tailings
were preferably discharged near the mines and few tailings storage facilities were constructed in mainland China. This
situation has significantly changed since 2000, because the Chinese economy is growing rapidly and Chinese regulations
and legislation require that tailings disposal systems must be ready before the mining operation begins. Consequently, data
up to 2008 shows that more than 12 000 tailings storage facilities have been built in China. This paper reviews the history of
tailings disposal in China, discusses three cases of tailings dam failures and explores failure mechanisms, and the procedures
commonly used in China for planning, design, construction and management of tailings impoundments. This paper also
discusses the current situation, shortcomings and key weaknesses, as well as future development trends for tailings storage
facilities in China.
Tailings disposal, tailings management, tailings dam failures, environmental hazards, China tailings dams
1 State Key Laboratory of Coal Mine Disaster Dynamics and Control,
Chongqing University, Chongqing, China
2 School of Mechanical and Chemical Engineering, The University of
Western Australia, Crawley, Western Australia, Australia
3 State and Local Joint Engineering Laboratory of Methane Drainage
in Complex Coal Gas Seam, Chongqing University, Chongqing, China
4 College of Resource and Environmental Science, Chongqing
University, Chongqing, China
Corresponding author:
Zuoan Wei, State Key Laboratory of Coal Mine Disaster Dynamics
and Control, Chongqing University, No. 174 Shapingba Zhengjie,
Chongqing, 400030, China.
462281WMR31110.1177/0734242X12462281Waste Management & ResearchWei et al.
Short Report
Wei et al. 107
impoundments in China are also discussed. Finally the current
situation, key weaknesses, and future development trends for
tailings storage facilities in China are presented.
History of tailings disposal
From 1949 to the present day, the history of tailings disposal in
China can be divided into the following four major phases.
Prior to 1958, mainland China had a few mines and the pro-
duction of minerals by milling was relatively small in quantity.
For example, the steel production in 1949 was only about
158 000 tonnes per year. Such a low production only required a
small amount of mine resources and thus the disposal of the tail-
ings was not considered as a problem.
Between 1958 and 1978, the national mining industry started
a phase of new development and growth. In 1958, the Chinese
government launched a campaign of increased steel-making,
requesting that steel and iron production achieved 10 700 000
tonnes per year. At that time only a few ore mines, such as Hainan
iron ore mine, Anshan iron ore mine, and Yunnan tin mine were
either planned or operating in the whole country. These were
small and medium-sized state-owned mines. During this period,
mineral processing technology was poorly developed and the
production of mineral milling was relatively small. Only some
medium-size mines built specific tailings storage facilities. Most
of the mines had no tailings disposal facilities due to poor envi-
ronmental protection awareness. Their tailings were directly dis-
charged into valleys or rivers near the mines. This situation did
not change much until the late 1980s.
From 1978 to 2000, the number of tailings disposal facilities
steadily increased, and the mine environment slowly changed.
The Chinese government promulgated the first Environmental
Protection Law in 1989 and relevant regulations in 1996, respec-
tively. According to these legislative codes, all mines must con-
struct tailings ponds otherwise the mine may be closed by local
government. Since then the quantity of tailings ponds has dra-
matically increased, reaching more than 6000 by the year 2000.
The planning, construction and operation of tailings storage facil-
ities has become an increasingly important issue for miners.
From 2000 to the present, the mining industry has developed
rapidly along with the rapid economic development within China.
The quantities of tailings discharged from mines also increased
considerably. Data show that there were more than 12 000
tailings ponds up to 2008 (Yin et al., 2011). With the increase of
the number of tailings ponds, some disastrous failures of tailings
dams have occasionally occurred. Consequently the issue of
safety of tailings ponds has become an increasing concern for
both local residents and governments.
Three examples of failure of tailing
dams in China
In conjunction with increased mineral production a number of tail-
ings dam failures have occurred in China since 1960. These fail-
ures have had significantly adverse socioeconomic consequences,
resulting in the loss of many lives, property damage and serious
pollution problems in downstream areas. The earliest documented
failure of a tailings dam took place in Yunnan province in 1962. At
that time, people did not fully appreciate the consequences of tail-
ings dam failures. Communications across the country were also
weak and sharing of information on failures was relatively poor.
Many small tailings dam failures were neither recorded nor
reported. Table 1 summarizes the main failures of tailings dams
that have occurred in China. From these limited records, three typi-
cal cases are analysed below.
Huogudu tin tailings pond, Yunnan
Huogudu tailings pond was owned by the Yunnan Tin Company
and located near Gejiu, a city in Yunnan province. This tailings
pond was designed in June 1956, constructed in July 1957, and
commissioned in August 1958. The pond was in a valley and the
tailings dam was built by the upstream method. At approximately
0230 to 0300 h on 26 September 1962, the main tailings dam rup-
tured after 3 days of moderate rainfall (see Figure 1). The breach
width was about 113 m on the top and 45 m at the bottom and its
depth was about 14 m. At the time of failure, the pond stored about
5.42 × 106 m3 tailings and the tailings dam reached 19.0 m in
height and 441.0 m in length. The failure released approximately
3.30 × 106 m3 of tailings and 3.8 × 105 m3 of water into down-
stream areas. The tailings flowed as far as 4.5 km from the dam
site. The tailings and water destroyed 11 villages, causing 171
deaths and 92 injuries, and rendered 13 970 persons homeless.
After the event, a forensic analysis was carried out by a specialist
team of professionals. The analysis revealed that the intense
Table 1. Main failures of tailings dams in China.
Name of dam Type of tailings Method of construction Year of failure Consequences of failure
Huogudu, Yunnan Tin Group Co., Yunnan Tin Upstream 1962 171 killed
Niujiaolong, Shizhuyuan Non-ferrous
Metals Co., Hunan
Copper Upstream 1985 49 killed
Longjiaoshan, Daye Iron Ore mine, Hubei Iron Upstream 1994 31 killed
Dachang, Nandan Tin mine, Guangxi Tin Upstream 2000 28 killed
Zhenan Gold mine, Shanxi Gold Upstream 2006 17 killed
Xiangfen tailings pond, Shanxi province Iron Upstream 2008 277 killed
108 Waste Management & Research 31(1)
rainfall was the direct cause of the failure, and the lack of experi-
ence in pond management was identified as an indirect cause.
Niujiaolong tailings pond, Hunan province
Niujiaolong tailings pond was owned by Shizhuyuan Zinc Mine
Company and located in a valley near the mine site. The tailings
dam was constructed by the upstream method. The system of tail-
ings ponds was commissioned in 1971 and the design operational
lifetime was 13 years. At that time the design height was 57 m,
and the design capacity was 2.15 × 106 m3.
A typhoon caused heavy rainstorms at the mine from 22 to 24
August 1985. In the early morning of 25 August the strong rain-
storms triggered some flash flooding and mud-debris flows
around the mine area. The debris flowed down the mountain and
entered into the Niujiaolong tailings pond from locations 1# to
5#, as shown in Figure 2. The debris flows forced the pond water
to overtop the tailings dam resulting in failure. At the time of
failure the tailings pond stored about 1.1 × 106 m3 tailings to a
height of 40 m. This failure released approximately 7.3 × 105 m3
tailings. The tailings flowed as far as 4.2 km from the dam site,
destroyed many houses, caused 49 deaths, and resulted in about
US$ 1.6 × 106 in direct losses. The failure also resulted in signifi-
cant pollution of the affected area. The cause of failure was
mainly attributed to meteorological conditions.
Xiangfen tailings pond, Shanxi province
Xiangfen tailings pond was built in a valley near an iron ore mine
in 1977. At that time, the iron ore mine was owned by a large
state-owned steel company. With the mining industry downturn
in the 1980s, the mine was shut down and tailings deposition was
suspended. In 2005, this mine was reopened by a local private
company. In September 2007, the tailings pond was illegally
reused by this company. Due to lack of proper tailings pond man-
agement, the tailings pond was simultaneously used for tailings
depositions and as a water reservoir for the concentrator mill. The
pond was also used to hold extracted groundwater.
At 0758 h on 8 September 2008 the tailings dam failed. At
that time, the tailings pond held about 2.9 × 105 m3 tailings
Figure 1. Plan view of Huogudu tailings pond.
Figure 2. Plan view of Niujiaolong tailings pond.
Wei et al. 109
and the dam was 50.7 m high. This failure released approxi-
mately 1.9 × 105 m3 tailings. The tailings flowed as far as 2.5 km
downstream and covered about 35 hectares of land. Figure 3
shows a photograph at the failure and a sketch of the extent of
the tailings slurry. The tailings destroyed many houses, caused
277 deaths, 33 injuries, and caused about US$ 1.3 × 107 in
direct losses. The failure also resulted in very serious social
The failure was mainly attributed to poor impoundment
management. First, in order to store more tailings, the slope of
the dam wall was built to a vertical (V): horizontal (H) ratio of
V 1 : H 1.4 (see Figure 4(a) and (b)) after the pond was ille-
gally reused, which is significantly steeper than the V 1 : H 4.0
to V 1 : H 5.0 as required by the applicable technical stand-
ards. Second, this tailings pond was incorrectly used as a
water reservoir to store water for the concentrator mill with
the supernatant pond kept at a high level. This combination
produced a relatively short tailings bench and a high phreatic
surface (Figure 4(b)) and resulted in significant seepage
through the dam wall. Finally, a loess wall 4.0 m wide was
built on the tailings dam wall (see Figure 4 (c)) in an attempt
to solve seepage and slope stability problems. The fine loess
material reduced seepage but this resulted in the saturation
zone inside the dam continually extending with the rising
water level, with a corresponding reduction in dam stability.
The tailings dam eventually failed under these worsening con-
ditions (see Figure 4(d)). This failure was therefore due to
human factors.
Cause analysis of tailings dam failures
In China, over 95% of tailings pond incidents occurred in opera-
tions. Tailings dam failures rarely occurred in abandoned or inac-
tive tailings ponds. Accidents were normally triggered by either
natural or human factors. Investigations show that the most com-
mon cause of tailings dam failure is related to heavy rainfall or
snowmelt events. Engineering design did not have a demon-
strated capability to cope with extreme-event climatic conditions
because of a lack of climatic data. This is despite a flood capacity
assessment being undertaken during design. Consequently, the
ponds did not have enough volume to store the flood water from
the surrounding areas and tailings dam failures occurred.
The second important cause is related to human factors, such
as poor design and construction of initial dyke and drainage cul-
verts, or poor management and inadequate maintenance activities
at the tailings dam sites. For example, the cause of failure of the
Shuanghe vanadium mine tailings pond in Shanxi province in
2008 was due to failure of the drainage culvert under the tailings
dam. This accident caused 3000 m3 tailings and waste water to
flow into downstream rivers. Illegal and extended use of tailings
ponds by some private miners are also a common human cause
for failures. Table 2 summarizes the proportional distributions of
the causes of tailings dam failures.
Procedure of design and construction
of tailings ponds
Prior to 1990, China was relatively lacking in technical standards
and guidelines for tailings storage facilities. Design, construc-
tion, and subsequent operational management of tailings ponds
were essentially carried out according to conventional water stor-
age specifications and experiences. In 1990, the first specific
design standard for tailings disposal, termed the Code for Design
of Tailings Disposal Facilities of Concentration Plant (ZBJ1-90),
was promulgated and implementation began in January 1991.
Since then, the design level of tailings ponds has been greatly
improved with the increasing number of tailings ponds built. By
March of 2006, a standard for safety management of tailings
ponds, termed the Safety Technical Regulations for the Tailings
Pond (AQ 2006-2005), was promulgated and implemented.
These safety regulations provide guidance to mine owners on
how to safely and environmentally manage tailings facilities.
Currently mine owners select professional design firms for tail-
ings dam design to ensure project success. The design procedure
is divided into the three main steps listed here, based on the
1. Collect data and information. The information mainly com-
prises the capacity per year of the concentration plant, ore
type, processing type, tailings characteristics, local meteoro-
logical and hydrological data for the mine, and so on.
2. Determine the site of tailings pond. Several possible sites are
chosen based on a topographic map of the mine area. Then
each possible site is evaluated based on field investigations,
Figure 3. Failure of Xiangfen tailings dam: (a) picture of the
tailings pond after failure; (b) sketch plan of the tailings slurry
flowing downstream.
110 Waste Management & Research 31(1)
analysis and calculations. Their advantages and disadvan-
tages are assessed to determine the most suitable site.
3. Produce drawings and documents describing the tailings disposal
facility. After the site of the tailings pond is determined, the pri-
mary design document is formed by the design firm according to
related national standards. The primary design is then examined
officially by a specialist group organized by the local government
and detailed construction drawings are created by the design firm.
At this step, two most important calculations have to be carried
out according to the ZBJ1-90: the stability analysis of the tailings
dam, in which the limit equilibrium method is recommended, and
the flood control capacity analysis (maximum probable flood) of
tailings pond and drainage system.
Once all the construction drawings of the tailings pond have been
completed, tenders or bids are requested from the mine owner to
select a construction company for the project construction. The
construction project typically includes the starter dyke, transportation
system of the tailings slurry from the mill to the pond, the drainage
system of the pond and other facilities. Once the construction project
is completed and officially credited, the project is handed over to the
mine owner. The project starts the operation and the mine owner
takes responsibility for the project management and operation.
Based on Chinese laws, the design firm and the construction
company must have their professional licences and certificates
for design and construction of tailings storage facilities.
Otherwise, these facilities are illegal and companies may be pros-
ecuted under law.
Current situation and further
development in China
Characteristics of tailings ponds
At the end of 2008, there were 12 655 tailings ponds in China.
Their distribution is summarized in Table 3, and their character-
istics are summarized in the following list.
1. The quantity of tailings ponds is very large and widely dis-
tributed across China. Only a few provinces such as Shanghai
and Tianjin do not have tailings ponds. About 200 additional
tailings ponds are constructed each year (Yin et al., 2004).
2. Most tailings ponds are small in size. Among all the tailings
ponds, 12 122 tailings ponds are classified as small,
accounting for 95.8% of the total volume. In this context
small represents less than 60 m in dam height. Furthermore,
over 60% of the tailings dams are less than 10-30 m in
height. Most of these small tailings ponds belong to private
3. Ninety-five percent of the tailings dams were constructed by
the upstream method, the simplest and most economical con-
struction method that is generally available. Unfortunately,
these tailings dams are also inherently weaker and less stable
than those dams constructed using other methods.
Main issues for safety enhancement
Although great advances have been made in the safety manage-
ment of tailings ponds, the following issues in design, construction
and management of tailings ponds still require improvement.
1. Outdated technology and poor management. The upstream
method is the oldest construction method and still the main
Figure 4. Construction procedure of tailings dam and failure
model: (a) the section of the tailings dam not reused until
2005; (b) the section of the tailings dam after reuse in 2007; (c)
the section of the tailings dam before the failure; (d) the failure
caused sliding.
Table 2. Statistical distribution of tailings dam failure causes
in China.
Main causes of dam failure Rate (%)
Start dyke seepage 5.1
Raised dyke break 9.0
Slope seepage 14.1
Drainage facilities damage 28.2
Flood overtopping/overflow 25.6
Dam slope instability 1.3
Landslide around tailings pond 14.1
Seismic liquefaction 2.6
Wei et al. 111
method for tailings dam construction in China. The only
design technical standard of tailings disposal (ZBJ 1-90) has
not been revised since it was implemented in 1990. Most of
the operators at the site are unskilled workers and most mines
are lacking professional advice or good tailings pond man-
agement. These situations frequently lead to accidents.
2. The equipment and technology for the safety monitoring of
tailings pond are of low standard and lag behind the current
development of the mining industry. Up to now, most tailings
dam safety management is based on experience due to lack of
effective monitoring tools. In some mines, monitoring facili-
ties were not of sufficient accuracy to act as an effective
3. Backfilling of underground mines is limited necessitating
storage of large volumes of tailings ponds and dams.
Future development
Statistically tailings ponds are one of the main sources of risk for
the mining industry. The safe management of tailings facilities is
of increasing concern for both local governments and local com-
munities. Consequently technical standards for design, construc-
tion and management of tailings ponds require urgent revision.
The government and the national societies of mines should
increase investment to support application research and technical
innovation in line with the rate of increase in mining. At present,
the following main development trends are envisaged.
Table 3. Distribution of tailings ponds in mainland China (in 2008).
No. Province Total tailings ponds Active Inactive Closed Constructing
1 Jiangsu 19 13 0 5 1
2 Beijing 37 9 0 28 0
3 Qinghai 57 10 44 1 2
4 Heilongjiang 62 45 3 0 14
5 Zhejiang 78 44 8 25 1
6 Xinjiang 103 47 0 11 45
7 Sichuan 137 87 6 7 37
8 Jilin 167 112 2 22 31
9 Gansu 183 107 24 8 44
10 Guizhou 219 103 36 50 30
11 Guangdong 226 63 101 47 15
12 Hubei 236 54 149 3 30
13 Fujian 247 136 0 36 75
14 Shanxi 269 125 25 49 70
15 Anhui 341 263 6 27 45
16 Jiangxi 380 234 45 26 75
17 Shandong 494 252 25 136 81
18 Guangxi 504 184 136 116 68
19 Hunan 651 356 109 160 26
20 Henan 681 275 281 5 120
21 Inner Mongolia 685 449 118 14 104
22 Yunnan 692 457 54 104 77
23 Liaoning 1475 1091 90 120 174
24 Shanxi 1735 602 247 330 556
25 Hebei 2888 1773 343 614 158
1. Strengthen the application of research and technical innova-
tion. It is suggested that the centerline construction method
be considered for use. Some new methods such as the rein-
forced terraced fields method (RTFM) (Wei et al., 2006;
2008) can be also used. Furthermore, the government and
related agencies should carry out new research on engineered
tailings disposal, such as thickened discharge, paste fill, fil-
tered tailings and dry stacking. This may result in new depo-
sition methods and eliminate the need for tailings ponds.
2. Enhance safety management. The emphasis should be put on
pre-failure prevention rather than post-failure repair (Rico
et al., 2008a; 2008b).
3. Reutilization of tailings. For example, tailings can be reused
to produce building materials. This also prolongs the life of
storage facilities.
Conclusions and recommendation
Currently China has more than 12 000 tailings ponds, 95% of
which use the upstream method to construct their tailings dam.
The small size tailings ponds account for 95.8%, and most of
these belong to private miners. Whereas the design and construc-
tion of tailings storage facilities are in accordance with Chinese
regulations the level of operational management is lower in com-
parison with developed countries. This results in most of the tail-
ings ponds having one or more deficiencies. Monitoring
technology for tailings dam is also relatively poor. Although
112 Waste Management & Research 31(1)
assessment of flood capacity of the tailings impoundment is
undertaken during design, floods due to extreme climatic condi-
tions remain a direct cause of tailings dam failures. Another
direct cause of tailings dam failures is the low level of operation
management and lack of professional advice. The future develop-
ment trend is to carry out new engineering research and innova-
tion for tailings disposal, such as thickened discharge, paste fill,
filtered tailings and dry stack, as well as increased reutilization of
The authors are very grateful to Dr Allen L. Li (URS Australia Pty
Ltd., Australia) and Dr Shen Jiayi and anonymous reviewers for their
very useful comments and reviews.
This research has been funded by the National Natural Science
Foundation of China (No. 51074199).
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... Heavy metals can affect plants, trees, aquatic organisms, and wildlife, and poses the danger of human exposure through ingestion, inhalation, and skin contact (Demková et al. 2017;Ali et al. 2021;Liu et al. 2021). In the case of tailings dam failure, a tragedy will occur and the structures in the downstream of the tailings dam will be destroyed and human lives will be in danger, and it will cause a large amount of water and soil pollution and the loss of plant species on a large scale (Wei et al. 2013;Burritt and Christ 2018;do Carmo et al. 2017;Du et al. 2020;Islam and Murakami 2021;Lin et al. 2022;Otieno and Shukla 2023;). For example, the failure of the Jagersfontein tailings dam in South Africa occurred in September 2022, resulting in a mudslide through the town and surrounding farmland (Islam and Murakami 2021;Lin et al. 2022;Otieno and Shukla 2023). ...
Full-text available
In iron ore processing plants, different tailing streams are usually transferred to the tailings thickener for partial dewatering and finally transferred to the tailings dam as a single stream. Therefore, the mixing of different tailings streams happens. This way can challenge the process of reprocessing the tailings in the tailings dam since the mixing of different tailings streams causes more complexity in the mineralogical composition as well as the chemical composition of the tailings in the tailings dam. To solve this problem, the idea of separate characterization and separate upgradation of different tailings streams of an iron ore processing plant was carried out and a comparison was made between the results of magnetic upgradation of each tailings streams with the total tailings (i.e., the tailings in the tailings dam, which is a mixture of different tailings streams of the plant). Hence, the different tailings streams of an iron ore processing plant were sampled and characterize for total iron, FeO content, particle size distribution, mineralogical composition by X-ray diffraction (XRD), magnetic behavior by Davis tube tests, and dry solid tonnage rate. The characterization results showed that the iron grade and dominant iron ore mineral vary from one stream to another tailings stream of the iron ore processing plant. For instance, the total iron content of different tailings streams varies in the range of 18.46 to 64.68% and the dominate iron ore mineral in the Cobber tailings was hematite, but in the other tailings streams it was magnetite. The magnetic upgradation of the Cobber and Rougher tailings and also the total tailings were performed separately by the wet magnetic separation at different magnetic field intensities of 2000, 3500, 5000, and 15,000 Gauss. A concentrate with the highest iron grade of 61.79% and yield of 52.15% was produced from magnetic upgradation of the Rougher tailings, but magnetic upgradation of the total tailings produced a concentrate with the iron grade of 37% and yield of 15.2%. A comparison between the magnetic upgradation of the total tailings and the Cobber and Rougher tailings revealed that the upgradation of Rougher tailings results in a concentrate with higher iron grade and yield than the total tailings.
... In addition, there is an increasing concern with the reuse and conscious consumption of water, which has come to be seen as a high value-added good. Accidents involving tailings dams around the world, as exposed by Van Niekerk and Viljoen [2], Rico et al. [3] and Wei et al. [4], have increased the visibility for these structures. Brazilian legislation is also more restricted regarding dams in operation and inactive. ...
... The conventional way of stockpiling tailings materials in surface storage facilities may damage the mine site geotechnical stability and the local environment and cause economic problems. TSF has substantial security risks, and some significant tailings dam failures that occurred recently have resulted in disastrous environmental and human tragedies (Rico et al., 2008;Wei et al., 2013;Concha Larrauri and Lall, 2018;Piciullo et al., 2022). In 2019, the Brumadinho dam failure happened in Mina Córrego do Feijão, Minas Gerais, Brazil had released around 10 million cubic meters of mine tailings, and 270 people were killed (Rotta et al., 2020;Cheng et al., 2021;Grebby et al., 2021). ...
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The mining industry provides essential mineral resources for human society's development. However, this industry generates a large quantity of waste material while rapidly extracting valuable elements from ore, such as processed tailings. The existence of mined voids will cause surface subsidence, and the surface stockpiling of tailings and waste rocks occupy a large amount of land and the risk of Tailings Storage Facility (TSF) failure. This paper proposes tailings backfill technology to mitigate surface subsidence and provides an alternative disposal method for tailings generated during ore extraction. Tailings backfill technology prepares the slurry by adding a certain amount of cementitious material into the tailings and transporting it to the underground goaf through a pipeline. The backfill slurry could then gradually build up its strength during the hydration of. Cementitious material. A case study of a lead-zinc mine in the Inner Mongolia Autonomous Region of China using tailings backfill technology was introduced in detail to solve the problems of grassland collapse caused by mine excavation and environmental damage due to tailings disposal. Spread test and rheological test were carried out to study the flow characteristics of filling slurry and the uniaxial compressive strength (UCS) of backfill was tested as well. The result illustrates that the spread of the filling slurry with a solid content between 72% and 76% and cement-tailings ratio between 1:4 and 1:8 is greater than 14 cm, and the UCS of backfill is above 1 MPa. The research shows that the tailings backfill technology recycles tailings waste while mitigating surface grassland subsidence and land occupation of waste disposal. Tailings backfill technology can significantly reduce tailings discharge or even achieve no discharge. A leaching test for heavy metal element classification of the backfill sample was carried out. The results show that the heavy metal detection indicators meet the environmental protection standard requirements and will not cause secondary environmental pollution. Therefore, tailings backfill technology can realize green and efficient management of mine waste and has great application and promotion prospects.
... Large-scale mining and mineral processing generate large amounts of tailings as solid waste and sludge [4,5]. Tailings storage is the main method of solid waste disposal in China; by 2009, more than 12,000 tailings ponds had been built in China, and the number is increasing [6]. As artificial landfill slopes with high potential energy and large volume, tailings ponds are a major source of danger because they may form mudflows or large landslide disasters in the case of dam failure [7]. ...
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Tailings dams are built to safely store tailings and to protect the natural environment from damage. However, tailings dam accidents occur frequently, endangering the safety of life and property, and causing pollution to the environment. Many tailings dam accidents are caused by seepage. As such, this study takes the No. II tailings dam of Ledong Baolun Gold Mine in Hainan Province as an example and builds a two-dimensional finite element model to simulate the seepage field. The effects of normal-water-level and high-water-level conditions on the total head, pressure head, and wetting line of the main and auxiliary dams were compared. The results show that higher water levels in both the main dam and the auxiliary dam lead to a higher pressure head at the top of the dam, lower pressure head at the bottom of the dam, higher total pressure head, and at the same time, a higher wetting line, and greater destabilization. In this study, the seepage deformation failure of the main dam and the auxiliary dam, in both cases, does not occur.
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A number of high-profile industrial accidents occurred at sludge and tailings storage facilities in different countries of the world are considered. The problem of ecological and technogenic danger of operating such objects, which leads to significant casualties among the civilian population, serious economic losses and harms the surrounding natural environment, is illustrated. The main causes of emergency situations have been established and analysed, it will help to reduce the risk of accidents and to minimize negative environmental consequences for similar facilities in Ukraine. The retrospective review covers the period from 1960 to 2022. During this time, about 150 cases of soil dams’ destruction in waste storage facilities were recorded. The different tendency in the frequency of accidents is noted. In particular, during the period from 1960 to 2009, there were 98 accidents with an average frequency of nearly two (1.98) per year. Over the last decade (2010-2020), the number of accidents reached 36 cases, and their frequency almost doubled to 3.6 accidents per year. Over the past two years, from the beginning of 2021 to December 2022, 10 accidents have already been registered. The vast majority of accidents during this period occurred in 34 countries of the world. The largest number of them was noted in the USA (22.4%), China (10.4%), Brazil (7.5%), Chile (6.7%), the Philippines (6.0%), Canada (5.2 %), Great Britain (4.5%) and other countries. Studies note jumps in the increase of accidents that have ten-year trends (1975, 1985, 1995, 2005). The general tendency of mass accidents since the beginning of 2015 is shown, which is substantiated by the expired terms of operation of many mining and ore enterprises (mines) and significant (exceeding normative) terms of operation of tailings storage facilities, which in some places were left without proper supervision and care. It was established that a violation of the dam slope stability (37%), an overflow of the designed capacity of the tailings storage facility (12%), seismic activity (11%), etc., are the main causes of accidents. A review of modern approaches to the management of dangerous anthropogenic objects and methods of diagnosing the technical condition of such structures was conducted. The use of a complex of organizational and technical solutions about the implementing the modern methods of assessment and control the technical condition of waste storage facilities at various levels of their operation and stages of the life cycle is proposed.
The potential breach of the tailings dams has caused the loss of many lives, considerable property damage, and irreversible pollution in downstream areas. Therefore, understanding the after-breach processes is a crucial step when performing a hazard analysis and response planning. In this investigation, the Yangtianqing tailings pond with possible fatality as a result of this dam failure might be classified as extreme failure consequence classification and was selected as a case study. Model tests and the corresponding numerical simulations were conducted to investigate the potential consequence of the runout of the tailings with respect to the hypothetical tailings dam breach. The results demonstrate the high risks of this typical “overhead tailings pond.” Downstream communities and other important facilities can be submerged in an extremely short period of time, thus, leaving very limited time to evacuate the residents and conduct a further emergency response. The potentially destructive power of the tailings slurry was emphasized by the high flow depth, impact force, and velocity of the tailings slurry that was 800 m downstream where the communities were located. A slurry-resisting barrier dam is proposed as a form of mitigation to protect the communities. The barrier dam can effectively reduce the mobility of the runout slurry. The results can serve as evidence for disaster mitigation and emergency management plan optimization.
Electrolytic Manganese Residue (EMR) is a solid waste containing soluble sulfate, discharged by electrolytic manganese industries. The accumulation of EMR in ponds poses a significant hazard to both safety and the environment. This study utilized innovative geotechnical test techniques to conduct a series of tests, investigating the effect of soluble salts on the geotechnical characteristics of EMR. The results revealed that soluble sulfates had a significant impact on the geotechnical characteristics of the EMR. In particular, the infiltration of water leached away the soluble salts, causing a non-uniform particle size distribution and decreasing the shear strength, stiffness, and liquefaction resistance of the EMR. Nevertheless, an increase in the stacking density of EMR could improve its mechanical characteristics and inhibited the dissolution of soluble salts. Therefore, increasing the density of stacked EMR, ensuring the effectiveness and non-obstruction of the water interception facilities, and reducing rainwater infiltration could be effective measures to enhance the safety and reduce the environmental hazard of EMR ponds.
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A tailings dam is normally constructed through self-consolidation with minimum compaction effort. Accordingly, special attention to the ultimate limit design in assessing the tailings dam instability condition is of primary importance. Furthermore, the existence of pore fluid chemical contaminants with high concentrations makes soil hydraulic and shear resistance properties subject to considerable changes.Therefore, this study aims to investigate the stability of a tailing dam using saturated-unsaturated flow analysis under 0.2 and 0.6 M sodium chloride solutions and pure water as a benchmark. To make the analyses as realistic as possible, recently developed solute-dependent hydraulic conductivity and water retention models are embedded into the numerical software. The results show that the saline-based model has higher pore water pressure than the pure water model due to more rainfall penetration by increasing the pore fluid salt concentration. Furthermore, increasing salt solution concentration enhances the tailing dam's drainagecondition, which leads to an increase in the dam's shear strength and, consequently, the factor of safety. Therefore, the stability of the tailings dam is improved by the combined impact of salt on both the flow and strength.
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A detailed search and re-evaluation of the known historical cases of tailings dam failure was carried out. A corpus of 147 cases of worldwide tailings dam disasters, from which 26 located in Europe, was compiled in a database. This contains six sections, including dam location, its physical and constructive characteristics, actual and putative failure cause, sludge hydrodynamics, socio-economical consequences and environmental impacts. Europe ranks in second place in reported accidents (18%), more than one third of them in dams 10-20 m high. In Europe, the most common cause of failure is related to unusual rain, whereas there is a lack of occurrences associated with seismic liquefaction, which is the second cause of tailings dam breakage elsewhere in the world. Moreover, over 90% of incidents occurred in active mines, and only 10% refer to abandoned ponds. The results reached by this preliminary analysis show an urgent need for EU regulations regarding technical standards of tailings disposal.
Surface disposition of mine tailings in paste form is a new disposal technique, and to achieve a desired depositional geometry, it is necessary to characterize the paste's flow properties. This study investigates how water content affects the flow behaviour and depositional geometry of tailings and kaolinite pastes, which are shear-thinning, high solids content, mineral pastes. A stress-controlled rheometer and a strain-controlled viscometer with vane fixtures were used to characterize the yield behaviour of the pastes, and three types of yield stress were determined. A flume apparatus was used to simulate paste deposition under laboratory conditions. The depositional angle, determined from the flume tests, and the yield stresses, determined from the rheometers, decreased as the water content increased. For each type of yield stress, a linear relationship was found between the depositional angle and the Sofra–Boger dimensionless group (τy′Fr/Re), with the linear coefficient depending on paste type.
The upstream method is a popular method for raising tailings dams. Currently in China there are more than 12,000 tailings impoundments and almost 95% of them use the upstream method for the construction of the dam. Statistical data has shown that the tailings impoundment is one of the main sources of risk in the mining industry. Failures of tailings impoundments have resulted in the loss of many lives, considerable property damage, and irreversible pollution in downstream areas. Therefore, the safety of tailings management facilities has been of increasing concern to governments and local communities. The management of a conventional tailings storage facility requires the maintenance of a high level of structural stability. Therefore, according to the relevant mine Acts, the mine operators are required to conduct stability analyses for all types of tailings facilities, whether they are new, active, or decommissioned. For the stability analysis of tailings dams, the accurate profile of the tailings dam is very important. The profiles are easily obtained for both active and decommissioned tailings facilities because their data can be collected through field investigations. However, collecting basic data from newly constructed tailings facilities is difficult. In this paper, a laboratory physical model test has been performed. The construction process for new tailings impoundment has been physically simulated in the laboratory, where the tailings particle composition and distribution below a beach, the change of phreatic surface of the dam, and the engineering properties of the tailings of the dam profiles have been measured. A new tailings facility, Yangtianqin tailings impoundment, owned by Tongchang copper mine of Yuxi Mine Co., was used as a case study to illustrate the physical modeling of the tailings dam. In the model test, the geometrical model of pond area was constructed according to the scale factor, λL, of 1:200 (model:prototype), and the tailings discharge system was also established, the tailings slurry then being discharged based on the design data. Finally, on the basis of the model test results on profiles, the stability analysis of the tailings dam at different heights was conducted under different conditions. The model test results and stability analysis show that the height of the tailings dam should be less than that originally planned. The original design of Yangtianqing tailings impoundment should therefore be revised for the safety of the tailings impoundment.
A characteristic common to most tailings dam failures is that the mine tailings tend to liquefy and flow over substantial distances, with potential for extensive damage to property and life. In order to be able to assess the potential for damage in case of such failure, it is necessary to be able to predict the characteristics of the flow and the possible extent of flood movement. This paper presents analytical procedures for making such evaluations. The behavior of tailings materials during flow is represented by a Bingham plastic rheological model in these analysis procedures. It is apparent from the analyses that the flow of phosphate tailings would be expected to be turbulent but flows for other types of tailings would be expected to be laminar. The procedures described are applicable for flow of tailings on horizontal and sloping planes and in prismatic valleys. The analyses can be performed using dimensionless charts in the case of flow on planes, and a computer program in the case of flow in prismatic valleys.
New mining technologies can exploit low-grade ores but they produce high volumes of waste, such as tailings. Further, current mineral processing techniques produce more and more fine tailings. How to dispose of these tailings is a key issue in the sustainable operation of a mine. A traditional method is to construct a settling or tailings pond for storage. Such a method requires sufficient coarse particles to raise a dam or embankment. However, the fine tailings contain little coarse particles and have poor mechanical properties. The stability of a tailings dam thus becomes a major issue if the traditional method is used. According to statistical data, all fine tailings dams or ponds in China have failed or have failure potential. Therefore, fine tailings disposal is a challenge to mine operators and new disposal methods should be explored for the stability improvement of tailings dams. In this paper, an innovative method of reinforced terraced fields is presented to satisfy the specific requirement of fine tailings disposal. By using an actual mine, this paper reports in detail the design concept and procedures for this method. Its feasibility is evaluated and its fundamental are analyzed.
Thesis (Ph. D.)--University of California, Berkeley, 1980. Includes bibliographical references (leaves 247-256). "8113085." Photocopy.
This paper compiles the available information on historic tailings dam failures with the purpose to establish simple correlations between tailings ponds geometric parameters (e.g., dam height, tailings volume) and the hydraulic characteristics of floods resulting from released tailings. Following the collapse of a mining waste dam, only a part of tailings and polluted water stored at the dam is released, and this outflow volume is difficult to estimate prior the incident. In this study, tailings' volume stored at the time of failure was shown to have a good correlation (r2=0.86) with the tailings outflow volume, and the volume of spilled tailings was correlated with its run-out distance (r2=0.57). An envelope curve was drawn encompassing the majority of data points indicating the potential maximum downstream distance affected by a tailings' spill. The application of the described regression equations for prediction purposes needs to be treated with caution and with support of on-site measurement and observations. However, they may provide a universal baseline approximation on tailing outflow characteristics (even if detailed dam information is unavailable), which is of a great importance for risk analysis purposes.
Fine Tailings and its Dam Stability Analysis
  • G Yin
  • Z Wei
  • J Xu
Yin G, Wei Z and Xu J (2004) Fine Tailings and its Dam Stability Analysis. Chongqing, China: Chongqing University Publishing House, pp. 1-4 [in Chinese].
The Reinforcement Terraced Fields Method
  • Wei Z Li
  • Sh
  • Liu
  • Zhao
Wei Z, Li SH, Liu X and Zhao Y (2006) The Reinforcement Terraced Fields Method. Chinese patent (No. 200610075635.3).
The Reinforcement Terraced Fields Method
  • Z Wei
  • S H Li
  • X Liu
  • Y Zhao
Wei Z, Li SH, Liu X and Zhao Y (2006) The Reinforcement Terraced Fields Method. Chinese patent (No. 200610075635.3).