Effects of Fertilizer and Sewage Sludge Treatments on Germination and Growth of Woody Plants in Metal Mine Tailings

Lee, Sul-Ki,Cho, Do-Soon The Ecological Society of Korea 2000 Journal of Ecology and Environment Vol.23 No.6

The effects of sludge and fertilizer application on germination and seedling growth of woody plants on heavy metal mine tailings were evaluated by greenhouse experiment. Two different mine tailings (Lead-zinc mine tailings from Kwangmyong, Kyonggi-do and tungsten mine tailings from Sangdong. Kangwon-do). four fertilizer treatments (N +P +K: 20, 40, 60, and 80 kg/m$^3$), and four sewage sludge treatments (5.5, 11, 22.5, and 45 Mg/m$^3$) were used in the experiment. Tested plants were Pinus densiflora, Larix leptolepis, Amorpha fruticosa, and Alnus hirsuta. There were three replicates for each treatment. In addition, vermiculite was used instead of mine tailings to determine the effect of physical amendments. Fifty seeds of a species were sown in a pot (upper diameter 13.5 cm, depth 10 cm) and seedling emergence were recorded daily for 30 days. The highest germination rate was 53% for all treatments. Germination rate of Larix leptolepis was lowest among the four species studied. One month later after seeding, seedlings were thinned and only 5 seedling were left in each pot, and fertilizer and sewage sludge were applied once again. Growth of seedlings were determined for 10 weeks since then. Most plants grew very poorly or died within 5 weeks on lead/zinc mine tailings from Kwangmyong. The analysis of heavy metal contents by the total dissolution method showed that heavy metals generally increased in the order of tungsten mine tailings from Sangdong < sewage sludge from Puchon < lead/zinc mine tailings from Kwangmyong. Growth of woody plants was improved significantly by the fertilizer treatments on tungsten mine tailings. In contrast. survival and growth of woody plants were not affected significantly by the sewage sludge treatment on both tailings. This study shows that fertilizer applied to established seeded stands may provide some benefits in terms of increased ground cover in the field. It is suggested that reclamation should be proceeded by the study of the physico-chemical and biological characteristics of mine tailings.

Effects of quartz-based mine tailings on characteristics and leaching behavior of ultra-high performance concrete

Pyo, Sukhoon,Tafesse, Million,Kim, Bong-Ju,Kim, Hyeong-Ki Elsevier 2018 Construction and Building Materials Vol.166 No.-

<P><B>Abstract</B></P> <P>High production cost and scarcity of raw materials may hinder the application and accessibility of ultra-high performance concrete (UHPC). In the present study, mine tailings, mineral waste products from mining sites, were applied to mitigate these problems. Two types of quartz-based mine tailings produced in South Korea were used to substitute silica powder and silica sand by half and fully in UHPC. The characteristics of UHPC with the tailings, including the compressive strength, workability, water absorption, and leachability of toxic elements, were experimentally evaluated. The effects of the tailings on the characteristics of UHPC varied according to the shape and size of particles of the tailings. The leaching of toxic trace elements from the tailings was highly controlled due to the chemical and physical capsulation of UHPC.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Mine tailings could substitute silica powder and sand in UHPC. </LI> <LI> Characteristics of UHPC were varied by the shape and size of tailings. </LI> <LI> Leaching of toxic elements in tailings was highly controlled by UHPC matrix. </LI> </UL> </P>

폐광산 오염원인 분석 및 오염경로, 향후 지속가능성에 대한 평가

김민규 ( Min Gyu Kim ),김기준 ( Ki-joon Kim ),정교철 ( Gyo-cheol Jeong ) 대한지질공학회 2018 지질공학 Vol.28 No.3

대영광산(일명 대마광산)은 함금은석영맥을 주 대상으로 채광한 금·은광산으로, 주 광해유발요인은 광물찌꺼기 적치장, 폐석장, 갱구 등 이다. 광물찌꺼기 적치장의 주 오염원소는 As와 Pb이다. 특히 As의 경우 3,424.41~3,803.61 mg/kg로 1지역 대책기준의 45배 이상으로 As에 의한 오염이 매우 심각한 것으로 파악되었다. 오염원소를 보면 오염원인 광물찌꺼기가 고농도의 As를 함유하고 있으며, 오염원의 영향을 받는 주변의 매체에서도 공통적으로 As 오염이 확인되고 있다. 이러한 As 오염은 광물찌꺼기 적치장과의 지형적 상관성이나 이격거리에 따라 오염정도가 달라지는 특성을 나타낸다. 즉 광물찌꺼기 적치장의 상류지역은 하류지역에 비해 오염정도가 낮으며, 광물찌꺼기 적치장의 하류지역에서는 광물찌꺼기 적치장과의 거리가 멀어질수록 오염도가 낮아지는 경향을 보인다. 특히 광물찌꺼기 적치장 주변에서 고농도 오염이 집중적으로 나타나고 있다. 이러한 특성으로 볼 때, 연구지역의 주 오염경로 중의 하나는 광물찌꺼기의 유실로 볼 수 있다. 광물찌꺼기 적치장 하류수계를 따라 As 오염이 확인되었으며, 이러한 현상은 현 하천보다는 구 하천에서 상대적으로 높게 나타나고 있다. 이는 광물찌꺼기 적치장에 대한 유실방지시설을 설치하기 전에 구 하천으로 다량의 광물찌꺼기가 유실되었음을 의미한다. 또한 광물찌꺼기 적치장의 하류수계 농경지에서 하천 범람 시에 영향을 상대적으로 더 받게 되는 하천변 50 m 이내의 농경지 오염도가 50 m 이상의 농경지에 비해 높게 나타났다. 이러한 특성으로 볼 때, 유실된 광물찌꺼기가 하천을 따라 이동하다가 범람에 의해 농경지로 유입되면서 오염이 발생하는 경로도 주 오염경로로 판단된다. Daeyoung mine (also called “Daema mine”) produced gold and silver from mainly gold- and silver-bearing quartz veins. The mine tailings are a waste hazard, but most of the tailings were swept away or dispersed throughout the area around the mine long before the tailing dump areas were transformed into agricultural land. Soil liner and protection facilities, such as retaining walls, were constructed in the mine area to prevent the loss of tailings. The content of the tailings is 3,424.41~3,803.61 mg/kg, which exceeds the safety standard by a factor of 45. In addition, contamination was detected near agricultural areas and in the sediments in downstream drainage channels. A high level of As contamination was concentrated near the waste tailings yard; comparaable levels were detected in agricultural areas close to streams that ran through the waste dump yard, whereas the levels were much lower in areas far from the streams. The contamination in stream sediments showed a gradual decrease with distance from the mine waste yard. Based on these contamination patterns, we concluded that there are two main paths that affect the spread of contaminants: (1) loss of mine waste, and (2) the introduction of mine waste into agricultural areas by floods after transportation by streams. The agricultural areas contaminated by mass inflow of mine waste can act as contamination sources themselves, affecting other agricultural areas through the diffusion of contaminants. At present, although the measured effect in minimal, sediments in streams are contaminated by exposed mine waste and surface liners. It is possible for contaminants to diffuse or spread into nearby areas if heavy elements trapped in soil grains in contaminated agricultural areas leach out as soil solution or contaminant particles during diffusion into the water supply.

중부지역에 위치한 폐광산 주변의 오염물질 이동성 평가

이종득,김태동,전기석,김휘중,Lee, Jong-Deuk,Kim, Tae-Dong,Jeon, Gee-Seok,Kim, Hee-Joung 한국지하수토양환경학회 2010 지하수토양환경 Vol.15 No.6

Several mines including Namil, Solim and Jungbong which are located in the Gyeonggi and Kangwon province have been abandoned and closed since 1980 due to "The promotion policy of mining industry". An enormous amount of mining wastes was disposed without proper treatment, which caused soil pollution in tailing dam and ore-dressing plant areas. However, any quantitative assessment was not performed about soil and water pollution by transporting mining wastes such as acid mine drainage, mine tailing, and rocky waste. In this research, heavy metals in mining wastes were analyzed according to leaching method which used 0.1 N HCl and total solution method which used Aqua-regia to recognize the ecological effect of distance from hot spot. We sampled tailings, rocky wastes and soils around the abandoned mine. Chemical and physical parameters such as pH, electrical conductivity (EC), total organic carbon (TOC), soil texture and heavy metal concentration were analyzed. The range of soil's pH is between 4.3 and 6.4 in the tailing dam and oredressing plant area due to mining activity. Total concentrations of As, Cu, and Pb in soil near ore dressing plant area are 250.9, 249.3 and 117.2 mg/kg respectively, which are higher than any other ones near tailing dam area. Arsenic concentration in tailing dams is 31.0 mg/kg, which is also considered as heavily polluted condition comparing with the remediation required level(RRL) in "Soil environment conservation Act".

광해오염원 추적을 위한 낙동강 지역 퇴적물 및 하천수의 화학조성 연구

김지윤,최의규,백승한,최혜빈,이정훈 한국지구과학회 2016 한국지구과학회지 Vol.37 No.4

There have been found mine tailings, wastes, and mining drainage scattered in the area of Nakdong River due to the improper maintenance of the abandoned mines. These contaminants can flow into rivers during the heavy rain periods in summer. Along the study area beginning Seokpo-myeon, Bonghwa-gun of Gyeongsangbuk-do untill Dosanmyeon, Andong-si, there are one hundred five mines including sixty metalliferous mines and forty-five nonmetal mines, which can adversely affect the adjacent rivers. To verify the contamination, we collected sediments, seepage water and surface water for a year both in rainy season and dry season. This study found that sediments, containing high concentrations of heavy metals caused by mining activities, are dispersed throughout the entire river basin (68 sample points with pollution index, based on the concentration of trace element, (PI) >10 among the total of 101 samples). The results of river water analysis indicated the increased concentrations of arsenic and cadmium at branches from Seungbu,Sambo, Okbang and Janggun mine, which concerns that the river water may be contaminated by mining drainage and tailing sediments. However, it is difficult to sort out the exact sources of contamination in sediments and waters only by using the chemical compositions. Thus the control of mining pollution is challenging. To prevent water from being contaminated by mining activities, we should be able to divide inflow rates from each origin of the mines. Therefore, there should be a continued study about how to trace the source of contaminants from mining activities by analyzing stable isotopes. 낙동강에는 휴·폐광산의 관리 소홀로 인하여 광미, 광산폐기물, 침출수 등이 산재되어 있으며 여름철 집중 호우기 동안 이 같은 오염물들이 수계에 유입될 수 있다. 경상북도 봉화군 석포면에서 시작해 안동시 안동호 상류에 이르기까지 낙동강에 영향을 미칠 수 있는 광산은 총 105개로 금속광산 60개, 비금속 광산 45개에 달한다. 이를 확인하기 위해서 1년 동안 건기와 우기에 퇴적물, 배출수, 하천수를 채취하였다. 광산의 활동으로 낙동강 주변에 전반적으로 심각한 수준의 중금속 오염을 보이는 퇴적층이 산재해 있음을 확인했다(101개의 시료채취 지점 중 중금속농도를 바탕으로 한 오염지수 10 이상 지점 68개). 하천수 분석 결과에서는 승부, 삼보, 옥방, 장군 광산 등의 지류 시료에서 비소와 카드뮴 농도가 우기 때 증가하는 양상을 보였으며 광산의 배출수와 광미 퇴적층으로 인한 오염이 우려된다. 그러나 광미 퇴적층과 하천수의 화학조성만으로는 오염의 근원이 되는 광산의 유입정도를 분리해 내기 어렵고 이러한 문제는 광해 방지를 어렵게 한다. 광산 활동으로 인한 오염을 효과적으로 방지하기 위해서는 각 오염근원으로부터의 유입비를 분리해 낼 수 있어야 하는데, 그 방법으로써 안정동위원소를 사용하고 이를 통한 오염원 추적 분석 기술 개발에 대한 연구가 필요하다.

생물계면활성제 람노리피드를 이용한 심해저 광업 잔재물 내 중금속 정화

김효진,김경련 대한환경공학회 2019 대한환경공학회지 Vol.41 No.10

Objectives : Rhamnolipid for the remediation of heavy metals in deep-sea mining tailings originated from manganese nodules was mainly focused in this research. As continued development depletes land-based metal resources, deep-sea natural resources such as manganese nodules collected from the Clarion-Clipperton Fracture Zone in the Pacific Ocean are inevitably drawing attention as useful alternative resources. The London protocol 1996 (LP) under International Maritime Organization (IMO) and the International Sea-bed Authority (ISA), however, will come up with the environmental guidelines of deep-sea mining tailings by early 2020s. Accordingly, there are urgently required to develop technologies that remediate heavy metals of deep-sea mining tailings. In this research, rhamnolipids which were known as biosurfactants was used to extracting agent for heavy metals in deep-sea mining tailings. Methods : Sample (20-63 μm, manganese nodules) made of 2% (w/v) liquid using ultrapure water were stirred and mixed with a rhamnolipid solution (0.05%, 0.1%, 0.2%, 0.3%) for various elapsed time, to evaluate the possibility of remediation of heavy metals in deep-sea mining tailings using rhamnolipid. Each mixture was analyzed for heavy metals eluted into the liquid after solid-liquid separation. Results and Discussion : Rhamnolipid was effective in removal of heavy metals and environmentally friendly. The extracted concentration of copper (Cu), zinc (Zn), nickel (Ni), and cadmium (Cd) were correspondingly enhanced with specific elapsed time and rhamnolipid’s concentrations, also. Conclusions : The results of this research should be used as basic data for the actual development of the remediation technology for deep-sea mining tailings using rhamnolipid in the future. 목적 : 본 연구는 생물계면활성제인 람노리피드(rhamnolipid)를 이용한 세척 처리에 의한 심해저 광업 잔재물 내중금속 정화 가능성을 평가하였다. 급격한 개발로 육상의 금속자원이 고갈됨에 따라, 대체자원으로 태평양의 클라리온-클립톤 구역(The Clarion-Clipperton Fracture Zone)의 망간 단괴 등 심해저 광물자원이 주목받고 있다. 하지만 국제해사기구(IMO) 산하 런던의정서(London Protocol 1996; LP)가 국제해저기구(ISA)와 심해저 광물자원 개발을위한 국제환경기준안을 2020년 초까지 수립할 예정이기 때문에, 심해저 광물자원 개발 시 발생하는 잔재물에 대한 정화(Remediation) 기술 또한 개발이 시급하다. Rhamnolipid는 생분해성을 가지는 친환경 생물계면활성제로, 토양 및 광산폐수에서 중금속 제거 효과를 입증한 바 있다. 본 연구에서는 rhamnolipid를 이용하여 심해저 광물자원내 중금속 정화 가능성을 평가하고, 경과시간 및 rhamnolipid 농도에 따른 다양한 조건에서의 중금속 용출 특성을평가하였다. 방법 : Rhamnolipid를 이용한 심해저 광물자원 내 중금속 정화 가능성을 평가하기 위하여, 초순수를 사용하여 2% (w/v)의 액상으로 만든 시료(20-63 μm, 망간 단괴)와 rhamnolipid용액(0.05%, 0.1%, 0.2%, 0.3% (w/v))을 다양한 경과시간 동안 교반・혼합하였다. 각각의 혼합물은 고상과 액상을 분리하여 액상에 용출된 중금속을 분석하였다. 결과 및 토의 : 연구 결과, 우선 처리대상물질로 선정한 구리, 아연, 니켈, 카드뮴에 대하여 용출된 중금속의 농도는경과시간 및 rhamnolipid 농도에 비례하여 증가하는 경향을 보였다. 결론 : 다양한 처리 조건에서 시료의 용출 특성을 기초로, 향후 rhamnolipid를 이용한 실제 심해저 광업 잔재물 정화 기술 개발을 위한 기초 자료로써 활용될 것이다.

폐금속 광산의 유형별 오염특성에 관한 연구

이종득,김태동,김선구,김휘중,Lee, Jong-Deuk,Kim, Tae Dong,Kim, Sun Gu,Kim, Hee-Joung 한국지하수토양환경학회 2013 지하수토양환경 Vol.18 No.3

This study is aimed to prepare the effective detail survey methods(Phase II) of abandoned metal mines through the contamination assessment for mine types and facilities in the abandoned metal mine areas. The study sites of 12 abandoned mines are located in Gyeonggi-do and Gangwon-do and those were chosen among 310 sites that the Phase II survey was conducted from 2007 to 2009 after considering the results of Phase I for abandoned mines scattered all over the country. 12 study sites were classified into four types; Type I sites only have pit mouth. Type II sites have pit mouth and mine-waste field. Type III sites have pit mouth and tailing sorting field. Type IV sites have pit mouth, tailing sorting field and concentrator(s). In forest land, paddy soil and farm land of Type I, As and Cd were showed average concentration, and Cu and Pb were high on the pit mouth area in one mines where the pit mouth was developed within 500 m. In the mines of Type II, Cu and Pb were showed average concentration too, but As and Cd were slightly high in pit mouth and mine-waste field. The mines of Type III which had grinding particle process through physical separation milling or hitting showed similar tendency with Type II. However, mines of Type IV pit mouth, mine-waste field and showed various results depending on defining the contamination sources. For example, if contamination source was pit mouth, the mixed results of Type I, II, II were showed. In tailing sorting field which was regarded as the most important source and having high mobility, however, if there were no facilities or it was difficult to access directly, field sampling was missed occasionally during phase I and phase II survey. For that reason, the assessment for tailing sorting field is missed and it leads to completely different results. In the areas of Type I mines, the concentration of heavy metals exceeded precautionary standards of soil contamination or not within 1,000 meters of pit mouth. Nickel(Ni) was the largest factor of the heavy metal contamination in this type. The heavy metals except Arsenic(As) were shown high levels of concentration in Type II areas, where pit mouth and mine-waste field were operated for making powder in upriver region; therefore, to the areas in the vicinity of midstream and downstream, the high content of heavy metals were shown. The tendency of high level of heavy metals and toxic materials contained in flotation agent used during sorting process were found in soil around sorting and tailing field. In the abandoned-pit-mouth area, drygrinding area and tailing sorting field area, the content of Cupper(Cu) and Zinc(Zn) were higher than other areas. Also, the contaminated area were larger than mine reclamation area(2,000 m) and the location of tailing sorting field was one of the important factors to estimate contaminated area.

폐광산 복구지역 잔류광미로 인한 주변 지하수·토양 오염가능성-시흥광산 사례

정예진,이상훈 대한자원환경지질학회 2001 자원환경지질 Vol.34 No.5

시흥광산은 1973년 폐광되었으며 1990년 초에 선광장 및 광미야적장에 있던 광미들을 제거한 후 그 자리에 소각장을 건설하는 폐광 복원작업을 실시하였다. 그러나 현재에도 광미가 완전히 제거되지 않았으며 광산 가동기간동안많은 양의 광미가 주변 토양 및 논으로 이동, 퇴적된 것이 확인되는 바 광미와 물 반응으로 인한 침출수 형성과 주변 지하수 ·토양의 중금속 오염이 예상된다. 본 연구는 잔류광미와 물 반응에 따른 광산배수의 지구화학적 진화과정을 분석하고 주변 지하수 ·토양 오염 가능성을 평가하고자 하였다 광미에서 추출한 공극수는 깊이에 따라 그 농도가 증가함을 보여 광미-물 반응을 통하여 지속적으로 중금속이 용출됨을 시사한다. 광미 중금속 용출은 공극수뿐 아니라 표면과 심부에서 각각 채취한 광미시료들간의 화학성분 차이에서도 확인된다. 광산 배수 기원지역과 하부 지역의 지하수 시료를 거리에 따라 채취, 분석한 결과 Cd, Pb 및 Zn 등은 국내 및 미국환경청 음용수 기준을 초과하며광산배수의 영향을 받은 결과로 해석된다. 실내 회분식 시험 결과 원소들은 농도가 급격히 감소하는 것과 비교적 일정한 농도를 보이는 두 가지 캉을 보였으며 이는 일부 원소들이 평형농도에 도달하고 있기 때문으로 생각된다. 회분식 시험에 사용한 증류수의 평균 pH는 6.5∼7.0의 범위로 이를 pH 4로 조정한 결과 원소들의 용출량이 급격히 증가하였다. 본 지역의 잔류광미는 지속적으로 주변의 지하수와 토양을 오염시킬 것으로 판단되며 이는 산성비등의 영향으로 인하여 급격히 증가할 것이다. The Shihung mine was restored in the early 90`s after abandonment for 20 years since 1973. Although disposed mine tailings were remoyed and the site was replaced by an incineration plant, still some residual mine tailings remainin the places including the old mine tailing disposal area and the adjacent agricultural area. These residual mine tail-ings are prone to impose an adyerse impact on the soil and groundwater and needs inyestigation for the potential con-tamination. Mine tailing samples were collected from the old tailing disposal area and the rice paddy. The porewaterfrom the mine tailing were exoacted and analysed to inyestigate chemical changes along the reaction path. Batchleaching tests were also cairied out in the laboratory to find any supporting eyidence ffund in the field anlysis. Eyi-dence of elemental leaching was confirmed both by the mine tailing and the porewater chemistry in them. The ele-ment concentrations of Cu, Cd, Pb, Zn in the porewater exceed the standard ffr drinking water of Korean goyeinmentand US EPA. Leaching of heavy metals from the mine tailing seem to be responsible ffr the contamination. In batchleaching test, heavy metals were either continuously released or declined rapidly. Eombining the inffimation withporewater Yariation with depths and the geochemical modeling results, most of elements are controlled by dissolutionanHor precipitation processes, with some solubility controlling solid phases (Cu, Pb, Fe and Zn). Batch leaching testconducted at fixed pH 4 showed much higher releases ffr the heavy metals up to 400 times (Zn) and this area isbecoming more vulnerable to soil and groundwater pollution as precipitation pH shills to acidic condition.

광물찌꺼기 적치장 붕괴 및 관리기준 해외 사례 조사

김세진,민기복,최용근,김지혜,이진수 한국자원공학회 2020 한국자원공학회지 Vol.57 No.6

A tailings dam is a facility for the deposition of remaining byproducts in the form of a dammed impoundment after the extraction of useful minerals in mines. If an accident occurs, such as collapse or spillage of a tailings dam, environmental pollution, human health effects, and property damage are anticipated. In particular, large-scale failures of tailings dams have occurred overseas recently. This study analyzed these cases and international management standards for tailings dams. The factors affecting the stability of a tailings dam include geometric conditions, geology, groundwater level, pore water pressure, the strength of tailings, and external conditions such as earthquakes and weather. Liquefaction was indicated as the most important mechanism of large-scale failure. Currently, there are no international management standards for tailings dams. However, there are management standards from Canada, Australia, and the International Council on Mining and Metals, which were reviewed in this study. 광물찌꺼기 적치장은 유용광물을 추출한 후 남은 부산물들을 댐 형태로 적치해둔 시설이다. 광물찌꺼기 적치장 붕괴 혹은유출과 같은 사고가 일어나면 인명, 재산피해 및 환경오염이 예상된다. 특히 최근 들어 큰 규모의 적치장 붕괴사건이 해외에서 일어나고 있고, 본 연구는 그에 따라 이러한 붕괴사례와 해외의 적치장 관리기준을 분석하였다. 광물찌꺼기 적치장 안정성에 영향을 끼치는인자로는 기하학적 조건, 지질, 지하수면, 간극수압, 강도 그리고 지진, 날씨와 같은 외부조건 등이 있다. 피해규모가 큰 붕괴사례들은액상화에 의한 붕괴가 가장 중요한 메커니즘으로 지목되었다. 적치장 관리기준에 대한 국제표준은 현재 없으나 캐나다, 호주 및 국제광업금속위원회(ICMM)에서 제시한 기준이 있어 본 연구에서 소개하였다.

Bioleaching of arsenic from highly contaminated mine tailings using Acidithiobacillus thiooxidans

Lee, E.,Han, Y.,Park, J.,Hong, J.,Silva, R.A.,Kim, S.,Kim, H. Academic Press 2015 Journal of environmental management Vol.147 No.-

The behavior of arsenic (As) bioleaching from mine tailings containing high amount of As (ca. 34,000 mg/kg) was investigated using Acidithiobacillus thiooxidans to get an insight on the optimal conditions that would be applied to practical heap and/or tank bioleaching tests. Initial pH (1.8-2.2), temperature (25-40 <SUP>o</SUP>C), and solid concentration (0.5-4.0%) were employed as experimental parameters. Complementary characterization experiments (e.g., XRD, SEM-EDS, electrophoretic mobility, cell density, and sulfate production) were also carried out to better understand the mechanism of As bioleaching. The results showed that final As leaching efficiency was similar regardless of initial pH. However, greater initial As leaching rate was observed at initial pH 1.8 than other conditions, which could be attributed to greater initial cell attachment to mine tailings. Unlike the trend observed when varying the initial pH, the final As leaching efficiency varied with the changes in temperature and solid concentration. Specifically, As leaching efficiency tended to decrease with increasing temperature due to the decrease in the bacterial growth rate at higher temperature. Meanwhile, As leaching efficiency tended to increase with decreasing solid concentration. The results for jarosite contents in mine tailings residue after bioleaching revealed that much greater amount of the jarosite was formed during the bioleaching reaction at higher solid concentration, suggesting that the coverage of the surface of the mine tailings by jarosite and/or the co-precipitation of the leached As with jarosite could be a dominant factor reducing As leaching efficiency.