ارزیابی ریسک زیست‌محیطی سد باطله معدن مس سونگون با استفاده از روش efmea

هدف اصلی از احداث سدهای باطله، مدیریت، جمع آوری و نگهداری مواد باطله معادن و پساب های حاصل از فعالیت های معدنی است. از طرفی مواد آلاینده خطرناک در پسماندها و زهاب های اسیدی ذخیره شده در سدهای باطله دارای پتانسیل ایجاد آثار سوء بر محیط زیست هستند. در این پژوهش سعی بر آن شده است که با استفاده از روش تجزیه وتحلیل حالات و اثرات شکست زیست محیطی، ریسک های زیست محیطی سد باطله معدن مس سونگون ارزیابی گردد و با پیشنهاد اقدامات مدیریتی مناسب جهت کاهش اثرات ریسک ها از بروز حوادث ناشی از نشت یا شکست سد باطله جلوگیری به عمل آید. در ابتدا خطرات بالقوه موجود در این سد باطله در سه دسته فیزیکی - شیمیایی، بیولوژیکی و اقتصادی - اجتماعی، از طریق بازدید میدانی و به کمک مصاحبه با کارشناسان خبره پروژه، و همچنین در قالب پرسشنامه هایی که توسط 18 نفر از کارشناسان خبره معدن مس سونگون تکمیل گردید، شناسایی شدند. بر اساس آنالیزهای انجام شده در محیط فیزیکی - شیمیایی، ریسک لرزه خیزی منطقه با 16،7 درصد، در محیط بیولوژیکی، ریسک آلودگی صوتی با 14،6 درصد و در محیط اجتماعی- اقتصادی، ریسک اثر بر چشم انداز با 19،3 درصد بالاترین امتیاز ریسک را کسب کردند سپس نتایج تحقیق حاضر با مطالعات پیشین مورد بحث و مقایسه قرار گرفت که از همسویی خوبی برخوردار بودند؛ ازاین رو می توان نتیجه گرفت که روش efmea به خوبی می تواند در ارزیابی ریسک های زیست محیطی سدهای باطله مورد استفاده قرار گیرد. همچنین، به منظور کاهش یا حذف خطرات و عوامل به وجود آورنده ریسک های محیط زیستی پیشنهاد می گردد دوره های بازرسی و پایش، متناسب با ریسک های شناسایی شده، جزء مهم ترین اهداف برنامه های مدیریتی قرار گیرد.

Environmental Risk Assessment of Sungun Copper Mine Tailing Dam Using EFMEA Method

IntroductionNowadays, the key role of mining industry in economic development, technology and urban growth in many countries around the world, including Iran, is not unknown. However, the mining industry is one of the highrisk industries and causes major environmental problems. Despite the positive achievements of mining, which has led to sustainable development in various countries around the world, due to the formation of huge volumes of waste materials from mineral activities, pollution from acidic drains, transfer of hazardous elements to surface and groundwater resources, and natural land and landscape destruction, it is one of the most dangerous industries and is one of the most important environmental problems. For this reason, environmental risk assessment has become particularly important in this industry. The purpose of this study was to evaluate the environmental risks of Sungun copper tailings dam using EFMEA method. The Sungun Dam tailing dam is considered a type of environmental threat because it is located in the upstream of agricultural lands and villages as well as one of the branches of SattarkhaneAhar river. To the best of authors’ knowledge, no study has been conducted on tailing dams risk assessment in the country; hence, the present study has analyzed the risks and threats of the Sungun tailing dam using the new EFMEA method.Study AreaThe tailing dam of the Sungun copper complex of Tabriz and its associated facilities is located on an area of ​​1400 hectares near the copper mine and its average elevation is 2313 meters above sea level and is located 130 km north of Tabriz and 30 km from Varzaghan city. It is a rock fill dam with clay core and has been built for the purpose of storing waste material extracted and processed from various activities of Sungun concentrator plant which is in operation since September 2006. Tailings dam infrastructures include: 1 Primary or initial dam (built for early storage in early years of operation), 2 Seepage or returned water (all foundation and body leakages are collected in this dam’s reservoir and pumped to the tailing dam reservoir station. Moreover, it has a maximum depth of 37.5 meters and length of 130 meters and prevents leakage of seepage water from the tailings dam to downstream) and 3 River diversion system (dam upstream cofferdam, temporary diversion channel, and diversion pipeline). & nbsp;Figure: Location of the Sungun ComplexMaterials and MethodsAt the beginning of the research, the background and history of past studies and the guidelines related to the research problem are identified. Gathering information about the study area will be conducted using library studies (theses related to the studied area, reports of the environment agency, etc.). Then, to determine the risks, a visit to the Sungun complex was carried out to identify the activities and potential risks of the tailing dam. After identifying the risk generating activities, a questionnaire was distributed to 18 environmental, safety and health professionals and personnel of the Sungun tailing dam. In the next step, to prioritize the risks, another questionnaire was again given to the same experts. & nbsp;Finally, based on the opinions expressed by experts, the risk factors in the three accepting environments (physicochemical, biological and socioeconomic) were determined. Due to the fact that the data collected from the questionnaires were qualitative, EFMEA method was used to quantify and analyze them. In this method, to determine the severity and probability of detection and occurrence of any potential risk in the receiving environments, specific tables related to the method of EFMEA were used.Results and DiscussionRisk Priority Number (RPN) was calculated for each of the risks in the physicochemical environment. The results show that seismicity with numerical value of 21.08 has the highest and flooding rate and flood risk with numerical value of 2.45 has the lowest numerical risk value. The results of numerical calculation of risk in biological environment show that noise pollution with numerical value of 18.24 has the highest numerical risk value. The lowest risk priority number was associated with an animal mortality with risk value of 3.99. Furthermore, the results of numerical calculation of the risks identified in the socioeconomic environment show that the highest numerical value of the risk is related to the effect on the landscape with 24.12 and the lowest numerical value of risk is related to the risk of reducing or closing the mine production with 0.81. Comparison of the results of this research with previous studies shows that the results of the present study are in good agreement with previous research.According to the results of the present study, the most important risk in the physiochemical environment was the seismicity of the region. In the literature review, it has been observed that the importance of this risk has been such that several studies have examined the effects of this risk in the field of mining and waste dams as a very important risk and concern of those in charge. Moreover, according to the regulations for designing buildings against earthquakes in Iran (Standard 2800), the main area of the Sungun copper mine tailings dam area is located on a relatively high seismic risk zone, which also confirms the importance of seismic risk in this dam.Furthermore, the present study identified noise pollution as the most important risk in the biological environment of the project under study, which is affected by the sound of explosions in mines and the operation of machinery. According to researchers, for many mining activities, the management of noise emission levels is a very important point in the operational phase of mining. For this reason, the use of noise reduction equipment for employees should be seriously put on the agenda.The risk of destructive effects on the landscape was also obtained as the most severe risk in the socioeconomic environment of the Sungun copper mine tailings dam. Researchers have found that waste dams have a negative impact on the environment, such as the extinction of plant and animal species and the disturbance of the ecosystem 's balance. In another study, ecosystem degradation was identified as the most important environmental risk in the Angoran zinc and lead mineral complex, which is consistent with the results of current research.ConclusionThe main purpose of construction of tailings dams is to manage, collect and maintain tailings waste and effluents from mining activities. On the other hand, hazardous pollutants in acidic waste and scrap stored in tailings dams have the potential to cause adverse effects on the environment. In the present study, the environmental risks of the Sungun copper mine dam were evaluated by using EFMEA method in order to prevent accidental dam leakage or failure. In order to reduce or eliminate the risks and factors that cause environmental risks, inspection and monitoring periods in accordance with the identified risks should be considered as one of the most important objectives of the management programs. Moreover, it can also be concluded from the results of this research and its discussion that the method of analyzing the modes and effects of environmental failure (with regard to the nondetection parameter) is a suitable and efficient method for assessing environmental risks in tailing dams. Applying fuzzy logic as well as assessing environmental opportunities can be considered as topics for future research.