❤❤❤ J & V Drywall Construction Case Study
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This will cause the above three stages to be recurring, and the time crosses each other, making the dam break process more complicated. There is currently no suitable model to simulate the above process during the situation of overtopping, mainly due to flood erosion of the tailings dam until instability. Worldwide, there are few studies on the mechanism of damage to tailings dams in flood situations. However, the research results of earth-rock dams can be used for reference to analyze tailings dams. The erosion mechanism can be attributed to hydraulic erosion and gravity erosion. When the flood top flows through the slope of the tailings dam, the incoming flow intensity is greater than the osmotic strength of the tailings sand, and runoff is formed on the dam surface.
The runoff causes the trench on the surface of the tailing dam, resulting in hydraulic erosion. After the overtopping situation occurs, part of the water seeps into the tailings dam, causing the tailings sand to saturate, increasing the dead weight of the tailings dam and causing gravity erosion. At the same time, the tailings sand is saturated to reduce the strength of the tailings sand, further reducing the stability of the tailings dam. Examples of dam break events caused by overtopping are briefly described and listed in Table 4. The tailings dam broke after a few hours of thundershowers [ ].
It is worth mentioning that this tailings pond is basically an upstream structure with less freeboard length and less reservoir area. When the flow rate of the overtopping water flow was greater than the starting flow rate of the tailings, the tailings dam continued to cause downward and bilateral erosion [ 23 , 65 ]. The hydraulic erosion caused the breach of the tailings dam to expand, and the slope became steep, which caused the tailings dam to collapse locally and completely. Wanger et al. At the early stages of flooding over the dam, the dam break process can be divided into the following 5 steps. They are 1 a small gully appeared on the tailings dam after a rainstorm, 2 erosion of loose tailings in the lower slope, 3 local instability of the lower slope tailings butter , 4 the water level in the tailings pond is high and the flood erosion tailings dam, and 5 local instability on a central slope, the failed material is washed away.
At the later stages of flooding over the dam, the dam break process can be divided into the following 3 steps, they are as follows: 1 after the erosion, the tailings dam slope began to be unstable overall, and the tailings sand was taken away by the water, 2 the tailings dam slope continues to be unstable under the domino effect, and the tailings sand is taken away, and 3 a large amount of tailings flow causes the slope to be unstable. In September , the Zijin tailings pond dam in Guangdong, China, collapsed suddenly. The crop area affected was The collapse of the tailings pond dam was due to the heavy rains brought on by the Fanapi typhoon and neglectful work of the mining department [ ].
The main cause of flooding and tailings reservoir collapse was that the height of the tailings reservoir drainage well entrance did not meet established standards, and the management and operation of the tailings pond were not in compliance with regulations. The indirect cause of the dam collapse was that the hydrogeological parameters of the tailings pond design were not suitable, resulting in low flood control standards for the tailings pond dam. The negligence of the design, supervision, and construction departments also led to the incident [ ]. Another reason for the tailings dam breakage was the lack of effective management of the tailings facilities which is a key factor for ensuring the safety and stability of tailings dams [ ].
Effective management of mine tailings includes not only controlling environmental impacts but also need to be subject to the legal document [ ]. The mechanism of earthquake-induced dam breakages in tailings ponds is mainly caused by the liquefaction of the tailings sand which is triggered by earthquakes that weaken the strength of the tailings material, causing large permanent deformation and destabilized the tailings dam [ ]. The main factors affecting the liquefaction of tailings are the composition, shape, size, gradation, arrangement, compactness, depth of the wetting line, and seismic intensity.
The study on the seismic performance of the tailings dam started late, and the dam structure has more significant anisotropy and heterogeneity, coupled with the shallow groundwater burial in the dam. Compared with similar earth-rock dams, the research and understanding of the seismic response and failure mechanism of tailings dams are low. In order to recognize the possibility of damage to the tailings pond after the earthquake, the analysis of the postearthquake stability of the tailings pond is increasingly incorporated into the design and evaluation process. Seismic performance of tailings dams should include seismic liquefaction analysis, seismic stability analysis, and seismic permanent deformation analysis.
Some research has been done on the study of the dynamic response of tailings dams. Finn et al. Xin and Finn analyzed the dynamic response of the damaged Dashihe tailings dam in the Tangshan earthquake and obtained the simulation results consistent with the postearthquake macroscopic survey results [ ]. Psarropoulos and Tsompanakis [ ] used the equivalent viscoelastic model to consider the nonlinear characteristics of foundation soil and tailings and simulated the dynamic response of different types of tailings dam under earthquake action. Liu et al. Liquefaction is the main cause of damage to high tailings dams; the influence of seismic inertial force on the seismic stability of high dams is secondary.
Ferdosi et al. The effects of different waste rock reinforcement methods on the seismic performance of tailings dams are analyzed under simulated seismic waves with different frequencies. Compared to high-frequency waves, low frequencies tend to produce larger deformations and larger critical displacement volumes of tailings. Ozcan et al. The effects of various factors under different conditions were evaluated, including the density and rigidity of the tailings and the presence of drainage inclusions, and focused on the introduction and discussion of the development of excess pore water pressure.
It is concluded that inclusions have a significant effect on the dynamic response of tailings and the occurrence of liquefaction. Moreover, the horizontal deformation is greater than the vertical deformation. Certain scholars have analyzed the stability mechanism of the tailings dam earthquake loss. It is considered that the stacking material of the tailings dam is relatively loose, and the tailings dam body below the surface is saturated sand. Under the seismic load, the dam body material may be subject to the vibration liquefaction phenomenon [ ].
Due to the inhomogeneity of the soil properties and the inconsistent pore pressure development of the entire dam, liquefaction starts from the local areas, and local liquefaction causes stress and deformation, resulting in a rise in nonliquefied soil pore pressure and reduction in strength, ultimately leading to a damaged dam [ ]. Before the tailings dam slippage damage, the internal stress of the dam body is diffused by flow slip and a large weak layer may form inside. As the seismic load and liquefaction increase, the weak layer eventually penetrates until the tailings dam losses stability [ 6 , 11 , ]. Under this mechanism, the impact of earthquakes on the stability of tailings dams is mainly manifested in the liquefaction of tailings.
When liquefaction begins to appear in the tailings dam, it is easy for a fissure seepage channel to form and cause local collapse. Simultaneously, the earthquake increases the sliding force or torque of the dam, causing it to slip and break [ 13 ]. At present, global seismic activity is becoming more and more active, and the distribution of mineral resources has a certain relationship with the distribution of seismic belts. Therefore, how to accurately evaluate the seismic performance of tailings dams is still a challenging problem to be solved. Various dam breakage events caused by earthquakes are briefly described and listed in Table 5. More than people died during the destruction of the El Cobre town [ 6 , 31 , 33 , 34 ].
This tailings dam failure was mainly caused by earthquake liquefaction and flow failure [ ]. The majority of breakage events are related to dams that were built using the upstream method. The following four main factors contributed to the instability of this Chilean tailings dam: 1 the construction method of tailings dam; 2 a low degree of compaction; 3 fine particle size of tailings sand; and 4 high saturation of tailings sand [ 6 , ].
Another reason was that the designer did not design the dam according to the established criterion. In earthquake-prone areas, downstream or centerline methods should be used to build dams to reduce accidents [ ]. The most serious damage caused by the earthquake was the failure of the Tapo Canyon tailings dam [ — ]. Although the tailings pond was filled two years prior, the tailings and dam sections were already saturated at the time of the earthquake. After the tailings pond closed, there was a lack of management which led to the accumulation of large amounts of water in the deep reservoir area and the tailings were kept in a saturated state for a long time. In general, if the water in the reservoir area is discharged in time, the damage of the earthquake to the dam can be minimized [ 50 ].
An earthquake occurred in eastern Japan in , and the Kayakari dam at the Ohya mine liquefied because of the tailings material, releasing a large amount of clay and causing damage to the downstream environment [ 60 , ]. Studies have shown that liquefaction leads to a significant reduction in the safety factors of tailings dams [ ]. In addition, the construction method of the dam body, the particle size of the tailings, and the magnitude of the earthquake all affects the stability of the tailings dam during an earthquake [ ]. In fact, the data on the failure of the tailings dam are incomplete. The information collected in this paper forms only part of the actual number of tailings dam accidents in the world as small accidents tend to occur frequently [ 28 , 29 , , ].
In addition, many accidents are not reported to the government in time because managers are afraid of taking legal responsibility [ 81 ]. This article presents as much of the basic information as possible about selected tailings dam breakages including location, cause, dam construction method, and dam height. The relationship between these data and the safety and stability of tailings dams is also summarized and listed in Table 1 and depicted in Figures 3 — 8. Figure 3 demonstrates that tailings dam failure has remained at a relatively high number for decades. From the beginning of the twentieth century to the s, the number of tailings dam breaks was small, and the occurrence was mainly concentrated in the United States, Chile, and other countries.
Chile is rich in mineral resources and has been mining mineral resources early. Chile is located at the plate junction, causing frequent earthquakes. In addition, the construction requirements of the tailings dam are low, resulting in the occurrence of the tailings dam failure. In the last sixty years, with the rapid development of industry, the number of tailings dams has gradually increased, but there are poor inspection and maintenance practices in place.
The unreasonable disposal of tailings dam has caused about large-scale tailings dam collapses every year, causing irreversible damage to the ecological environment and life safety. Tailings dam failure events usually occur in developing countries with rapid economic development e. In the next few decades, this paper speculates that a high ratio of tailings dam failures will remain. In order to solve this problem, it is necessary for the state to improve the construction specifications of tailings dams and strengthen the safety management of tailings dams. In the process of industrial development, it is also necessary to ensure engineering safety and protect the environment. The proportion of accidents in South America, Asia, and Europe is relatively small, after comparison with North America.
In South America, the number of tailings dam accidents in Chile, Brazil, and Peru is high, and the damage is serious. In Asia, China, and Japan are also countries with frequent tailings dam accidents. In Europe, the number of tailings dam breakouts in the United Kingdom is the highest. The situation described above is consistent with its economic development. Most of the tailings dam failures in developed countries occurred before the twenty-first century, which corresponds to the period of rapid economic development, such as in the United States, the United Kingdom, and Canada.
Conversely, the majority of the tailings dam failures in developing countries occurred after the twenty-first century. Developing countries, such as Brazil, China, and Chile, need to pay attention to the safety and stability of tailings dams as their economies develop, whilst simultaneously improving the building standards of tailings dams. If necessary, developing countries can learn from the latest building standards of developed countries on tailings dams. One scholar divided the causes of tailings dam breakage into 11 categories, namely, seepage or piping, foundation failure, overtopping, seismic liquefaction earthquake , mine subsidence, unusual rain, snowmelt, structural, slope instability, maintenance, and unknown cause.
But many accidents are the result of a combination of multiple causes, and this classification has some overlapping parts, such as unusual rain, snowmelt, and overtopping. According to the main cause of tailings dam failure, the accident percentage of seepage, foundation failure, overtopping, earthquake, and others, are respectively, It can be seen from the collected data that extreme weather causes serious damage to the safety and stability of tailings dams. As human activities cause climate warming, the tailings dam failure ratio caused by extreme weather may gradually increase.
This distribution is generally similar for many countries although there are some differences. Considering the fast-growing economy of the United States, this phenomenon is reasonable. From the statistical data, we can draw a conclusion that most of these dams were established in the s and s. The dam failures frequently occurred due to the lack of management or disposal of small dams and old dams by managers. The height of the tailings dam can increase the storage of tailings, but it also increases the safety risk. Researchers need to conduct more systematic research, such as phreatic line and slope stability, to contribute to the safety and stability of the tailings dam.
The upstream constructed dams require fewer construction materials, but their dams have a high phreatic line and poor stability. Before the establishment of the tailings dam, it is necessary to evaluate the geological conditions and environmental factors comprehensively. A safe method of centerline construction method and downstream construction method is chosen to build a dam, thus reducing the number of dams built by upstream construction methods. In countries such as South Africa and China, tailing dam failures related to abnormal rainfall have occurred. Rain-rich countries should design suitable drainage systems and choose stable central and downstream construction techniques.
The reliable flood discharge system is conducive to the treatment of excess water in the reservoir area, thus ensuring safe and stable operation of the tailings dam. In countries with frequent earthquakes, such as Japan and Chile, the dangers caused by earthquakes to tailings dams should be fully considered. The foundation needs to be reinforced to ensure the safe operation of tailings dams. As in the cases described in this article, although many accidents are related to natural events, such as heavy rain and earthquakes, there are also technical defects, such as overtopping and seepage.
However, poorly constructed buildings and human activities near the tailings dam may cause settlement which can be monitored and effectively controlled. Several studies have shown that timely and effective management of tailings storage facilities, monitoring the factors that endanger the safety and stability of tailings dams, and detecting problems and repairing in time can effectively reduce the probability of accidents.
This paper collects newspapers, technical reports, scientific papers, and other electronic data to sort out the database of tailings dam failures in the world and then summarizes the main causes including seepage, foundation failure, overtopping, and earthquakes, as well as mechanisms of the classic examples for tailings dam failures. In order to understand the reason for the failure of the tailings dam, failure height, building type, geographical location, and time distribution, a brief discussion of the collected data was carried out. On a global scale, the following conclusions are drawn about tailings dam failure: i Based on the main cause of tailings dam failure, the accident percentage of seepage, foundation failure, overtopping, earthquake, and others is, respectively, The government can improve the building codes of small- and medium-sized dams, improve the safety and stability of dams, and reduce the number of dam breaks in future tailings dams.
Developing countries should learn from the experience and lessons of developed countries, and they should also try to use centerline or upstream construction methods. Downstream and centerline dams have good stability and less dam failure events. Downstream or centerline dam construction method is recommended to build the tailings dam. For the established upstream tailings dam, it is necessary to give sufficient supervision and management to care about the operation of the tailings dam, thereby reducing the risk of tailings dam breakage and ensuring project safety and property safety.
It is not difficult to infer that each tailing dam failures involve engineering and human factors and that these factors can be avoided. A human being should prevent the occurrence of tailings dam damage events, instead of repairing after the accident. For example, tailings dams should design with special attention given to important factors that have a major impact on the stability of the dam including site conditions hydrological conditions, geological conditions, and climate , choice of the embankment, and risk prediction heavy rains and typhoons.
In the operation and maintenance stage of the tailings dam, the medium and low tailings dam should be given more attention, and problems should be dealt quickly. Finally, the review of global dam failure information is beneficial to the management of tailings storage facilities and can effectively reduce the probability of tailings dam failures. The safety and stability of tailings dams require the joint effort of the government, design units, construction units, and supervision units. These previous studies and datasets are cited at relevant places within the text as reference [ 67 ].
The authors declare that there are no conflicts of interest regarding the publication of this paper. This is an open access article distributed under the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Article of the Year Award: Outstanding research contributions of , as selected by our Chief Editors.
Read the winning articles. Journal overview. Special Issues. Academic Editor: Hossein Moayedi. Received 19 Jan Revised 27 Apr Accepted 07 May Published 20 Jun Abstract On a global scale, the demand for mineral products has increased substantially with economic development. Introduction The mining industry has a significant impact on modern life, and its products are widely used in computers, airplanes, ships, and jewellery. Reasons and Mechanisms for the Current Tailings Dam Failures On a global scale, there have been many severe accidents related to tailings dams. Table 1. Basic information regarding tailings impoundment failures.
Figure 1. Number and types of tailings dam failures in several countries. Table 2. Table 3. Example of tailings dam failures caused by foundation failure. Table 4. Example of tailings dam failure caused by overtopping. Figure 2. Table 5. Example of tailings dam failure caused by earthquakes. Figure 3. Figure 4. Figure 5. Figure 6. Figure 7. Figure 8. References M. Bashwira, J. Cuvelier, D. Hilhorst, and G. Lghoul, A. Maqsoud, R. Hakkou, and A. Seccatore, M. Veiga, C. Origliasso, T. Marin, and G. Lyu, J. Chai, Z. Xu, and Y. Kossoff, W. Dubbin, M. Alfredsson, S. Edwards, M. Macklin, and K. Villavicencio, R. Espinace, J. Palma, A. Fourie, and P. Ozcan, R. Ulusay, and N.
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Your e-mail won't be published. Skip to content.Retrieved October 10, Planning is essential. The load J & V Drywall Construction Case Study by J & V Drywall Construction Case Study dam exceeded the J & V Drywall Construction Case Study capacity of the dam foundation material, causing shear damage to the A & F Vs. The Homeless Case Study foundation material.