Geochemistry of Mine Tailings from Processing of Siderite–Cu Ores and Mobility of Selected Metals and Metalloids Evaluated by a Pot Leaching Experiment at the Slovinky Impoundment,Eastern Slovakia

This work describes the geochemistry, mineralogy, and mobility of selected metals (Cu, Pb, Zn) and metalloids (As, Sb) in a tailings impoundment in the village of Slovinky (eastern Slovakia). The tailings were covered unevenly by slag from processing of Cu wastes. The tailings and slag both have negligible potential for acid mine drainage formation, thus neutral to alkaline conditions predominate, as shown by high paste pH values of the tailings (7.66–8.83) and neutral drainage, with pH values above 7.50. Weathering of the most abundant primary sulfides (chalcopyrite, pyrite, and arsenopyrite) releases low concentrations of As, Cu, Pb, Sb, and Zn from the tailings impoundment and in leachates from a 150 days pot leaching experiment. This is explained mostly by formation of secondary ferric oxyhydroxides (as weathering rims on the surfaces of primary sulfides or individual grains),which incorporate 4.09 wt% of As, 17.2 wt% of Cu, 1.20 wt% of Pb, 15.0 wt% of Sb, and 1.59 wt% of Zn. Elevated contents of metals and metalloids in weathering rims formed on slag components like glasses, metallic grains, and residues of blast-furnace lining indicate that secondary solid phases are controlling the mobility of the potentially toxic elements. Generally, with the exception of Cu, no separate secondary compounds of the metals or metalloids were found. The potentially toxic elements are mainly immobilized by ferric oxyhydroxides and other iron mineral phases in the tailings impoundment.     

Legacy of Cyanide and ARD at a Low-Scale Gold Mine (Furtei, Italy)

A gold deposit was exploited from 1997 to 2003 at Furtei, Sardinia (Italy). Gold and silver were recovered from oxidized ores by cyanidation; copper concentrates were separated from the sulfide ores by flotation. Following unplanned closure, sulfide-rich materials derived from mining and processing residues were left on site. During operation, cyanide solutions were disposed of in a tailings impoundment. The cyanide underwent natural degradation so that by 2011, cyanide concentrations in the tailings impoundment and seeps were below the Italian limit for industrial effluents. However, during the rainy season, sulfide-rich materials in the waste rock dumps produce extreme acidic solutions and concentrations of some dissolved contaminants, especially ammonium, aluminum, arsenic, copper, iron and manganese, still exceed discharge criteria in the tailings impoundment and seeps. Highly contaminated drainage flows downstream from the mine and poses a hazard to agricultural areas.     

Impact of Sewage Sludge on Groundwater Quality at a Formerly Remediated Tailings Impoundment

Sewage sludge can be a suitable, organic-rich substrate to promote vegetation of sulfide-mine tailings, but it may contain contaminants, that, when oxidized, can adversely affect underlying groundwater systems. The geochemical impact of a surface application of 12,000 metric tons of anaerobically-digested sewage sludge on the groundwater quality of a remediated sulfide-tailings impoundment in northern Sweden was evaluated to determine if sludge-borne metals and nitrate were released to the underlying groundwater system. Two years of data from a field-scale groundwater monitoring programme initiated just before the sludge application was compared to groundwater data from 1998 to 2006. Grass was successfully established within 2 years. However, until that occurred, elevated concentrations of sludge-borne metals (Cu, Ni, Pb, Zn) were released to the underlying groundwater. In addition, the release of nitrate likely exacerbated metal concentrations by providing an oxidant for pyrite in the underlying tailings. The release was periodic due to the establishment of the grass, which immobilized metals and nitrate in the sludge. Metals bound as organo-metallic complexes, due to dissolved organic carbon released from the sludge, migrated across the tailings impoundment. Model simulations indicate that the plume will take 6 years to exit the groundwater environment. Though the impacts are relatively short-term, this type of application should be reconsidered in the future.     

包钢选矿厂尾矿综合利用进展

包钢选矿厂尾矿是选铁、选稀土过程中产生的废弃物,其中含有大量稀土和铌等可利用的矿物组分,如果任其堆存废弃,必然要浪费这些宝贵的资源,而且尾矿堆存对生态环境还会造成极大的危害。因此,开展尾矿利用已成为当今矿业界的重要任务。本文对近年来包钢选矿厂尾矿综合利用取得的某些成果进行了综述,并对包钢选矿厂尾矿综合利用的发展方向提出了一些建议。     

Geochemical Characterisation of Seepage and Drainage Water Quality from Two Sulphide Mine Tailings Impoundments: Acid Mine Drainage versus Neutral Mine Drainage

Seepage water and drainage water geochemistry (pH, EC, O₂, redox, alkalinity, dissolved cations and trace metals, major anions, total element concentrations) were studied at two active sulphide mine tailings impoundments in Finland (the Hitura Ni mine and Luikonlahti Cu mine/talc processing plant). The data were used to assess the factors influencing tailings seepage quality and to identify constraints for water treatment. Changes in seepage water quality after equilibration with atmospheric conditions were evaluated based on geochemical modelling. At Luikonlahti, annual and seasonal changes were also studied. Seepage quality was largely influenced by the tailings mineralogy, and the serpentine-rich, low sulphide Hitura tailings produced neutral mine drainage with high Ni. In contrast, drainage from the high sulphide, multi-metal tailings of Luikonlahti represented typical acid mine drainage with elevated contents of Zn, Ni, Cu, and Co. Other factors affecting the seepage quality included weathering of the tailings along the seepage flow path, process water input, local hydrological settings, and structural changes in the tailings impoundment. Geochemical modelling showed that pH increased and some heavy metals were adsorbed to Fe precipitates after net alkaline waters equilibrated with the atmosphere. In the net acidic waters, pH decreased and no adsorption occurred. A combination of aerobic and anaerobic treatments is proposed for Hitura seepages to decrease the sulphate and metal loading. For Luikonlahti, prolonged monitoring of the seepage quality is suggested instead of treatment, since the water quality is still adjusting to recent modifications to the tailings impoundment.     

特大采空区充填技术

冬瓜山铜矿浅部东、西狮子山矿段开采结束后,形成了2个特大采空区一直没有得到处理,对矿山正常生产及周边环境造成了一定影响。冬瓜山铜矿深部矿体采场于2006年投产,矿山采选生产能力为13 000 t/d,选矿厂所产生尾砂量除正常进行深部采场充填外还略有多余,为了解决多余尾砂排放问题,采用尾砂充填方式对特大采空区进行处理,处理过程中解决了诸如封闭墙设计和滤排水以及尾砂输送与充填控制等问题,从而消除特大采空区存在所带来的安全隐患。     

水质对调军台选矿厂流程浮选影响的研究

鞍钢齐大山和调军台选矿厂的尾矿及调军台灰渣水毕排至同一个尾矿库，研究表明，按照水量平衡设计得出的一定组成的模拟尾矿水，虽含有微量石油磺酸钠捕收剂、聚铁絮凝剂的浮选用水，对调军台选矿厂浮选指标无影响。为该厂建成后使用放库回水提供了科学依据。     

基于浮选过程的液位控制系统研究

浮选控制作为选矿厂生产过程中的一个重要环节,直接影响选矿厂的效益指标,因此必须充分发挥矿山自动化、先进控制、智能仪表以及大数据分析等技术优势,提高浮选过程的生产指标,增加市场竞争力,以保证浮选作业工作的稳定,在保证精矿、尾矿品位合格且标准差稳定的前提下,有效提高精矿金属回收率。液位控制作为浮选生产过程重要的环节,直接影响泡沫的移动速度控制,从而对选矿关键指标品位和回收率产生影响,另外液位控制也是整个浮选控制的难点和重点,因为选矿厂浮选过程通常是长流程、多设备耦合、大滞后、非时变、非线性的生产过程,在液位调节过程必须考虑整个浮选系统的液位协同控制,否则将会给系统带来巨大扰动,导致整个浮选系统不可控,严重影响整个选矿厂的经济指标,因而对浮选过程液位控制系统展开研究。     

Distribution modelling of the nickel assay grades in final tailings at Raglan,Québec

The mining and milling operations at Raglan, northern Québec, treat an ultramafic, pervasively serpentinised nickel ore, and produce a final nickel concentrate by grinding and sulphide flotation. A final tailings stream is discarded. A study was made of the nickel chemical assays of the Raglan final tailings stream, using a data mining technique of operational measurements. A distribution model and probability plot using nickel chemical assays were produced from this study. It was found that the nickel assay values formed a residually lognormal bimodal distribution. By using a lognormal probability plot, this distribution may be semi–quantitatively decomposed into two subordinate distributions by using either visual interpretation or the TRIPOD software. It is proposed that these two subordinate distributions represent two different degrees of nickel mineral liberation. Independent QemSCAN mineral measurement of one of the two tailings studies shows agreement with these graphical interpretations. Repetition of this method after flowsheet changes that produced metallurgical performance improvements shows that this model responds to concentrator performance improvements, and may be used as a monitoring tool to interpret concentrator behaviour. The study opens up potential for further work. This has been identified and will be pursued.     

铜矿峪矿选矿厂工艺流程变革实践

介绍铜矿峪矿选矿厂工艺流程变革及效果。将原破碎 +自磨流程改为常规破碎 +球磨流程 ;磨矿浮选流程随着矿石性质变化而随时改进 ;精矿脱水流程和最终精矿泡沫输送尽量做到节能而又不造成金属流失 ;对碎矿除尘水及尾矿中的磁性铁进行回收。通过不断完善和改进工艺流程 ,取得了显著的经济效益。     

Mobility of Be,Bi, F,Ga, Ge and W in Surface Water and the Water Quality Impact on Epilithic Diatoms Downstream of the Historical Yxsjöberg Mine Site,Sweden

There is a potential risk that the geochemical cycles of several critical metals will be affected when mining of these metals increases to meet the demand of green technology. The geochemistry of Be, Bi, Ga, Ge, and W, herewith called CM5, is lacking, yet is necessary to ensure responsible mine waste and water management. Beryllium, Bi, and W are all considered immobile, but in previous studies of skarn tailings in Yxsjöberg, Sweden, all three elements were mobilized. The tailings are enriched in CM5, together with pyrrhotite, calcite, and fluorite. The mobility and environmental impact of CM5 and F in surface waters downstream of the Yxsjöberg mine site, Sweden, were studied using monthly water samples from seven locations and analysis of diatoms at five of these locations. Bismuth, Ge, and W were present at low concentrations, transported in the particulate phase, and likely settled in the sediments hundreds of meters from the tailings. Beryllium and F were present at high concentrations and dominantly transported in the dissolved phase. At these pH conditions (5.6), Be should form insoluble hydroxides; however, elevated concentrations of dissolved Be were observed more than 5 km from the mine site. Diatoms downstream of the mine site were negatively affected by the mine drainage. The release of low quality neutral mine drainage will continue for hundreds of years if remediation actions are not undertaken since only a small portion of the tailings have weathered during 50–100 years of storage.

     

Column leach study II: Heavy metal dissolution characteristics from selected lead-zinc mine tailings

Metal dissolution from tailings from six lead-zinc mine and milling sites in the western United States was examined by researchers from the Bureau of Mines using a column leaching procedure involving a formulated “western rain” leachant. This 2-year laboratory study included the effects of column waste depth, dry cycles with and without oxygen, and pore water evaporation. The results indicated that leachate metal concentrations gradually decreased with each leaching, but that the degree of enhanced metal mobilization from unsaturated tailings varied widely from waste to waste. Further studies on selected samples from this group of tailings demonstrated that the driving force behind enhanced metal dissolution is the oxidation of sulphide minerals by atmospheric oxygen during the evaporation of pore water from the columns of tailings. Leachates from water-saturated columns of these tailings gave pH values from 6.5 to 8.5; acid production and dissolved metal concentrations were enhanced by alternating wet and dry cycles. All studies to date indicate that maintaining tailings at or near saturation and/or excluding atmospheric oxygen produce leachates of nearly constant to slowly decreasing metal concentrations with each subsequent leaching.     

某钨钼选矿废水水质调研及混凝沉降试验研究

某钨钼选矿厂的选矿废水中含有超微细矿物颗粒和残留的选矿药剂,产生的浊度、悬浮物均较高,影响其直接回用,针对这一问题,首先对该厂的选矿废水水质进行了调研,摸清水质特征,继而进行了混凝沉降药剂探索试验,发现复配的BK-A混凝剂具有较好的沉降效果,随后又进行了现场混凝沉降优化试验研究。试验研究结果表明:BK-A混凝药剂最佳反应条件为:沉降pH值9～10,BK-A药剂投加量20～25mL/L,PAM投加量6mL/L,处理后的尾矿库选矿废水浊度和悬浮物指标基本能达到清水水质指标,尾矿库废水中硅酸根离子能稳定降至100mg/L左右。     

某选铁尾矿浮选锌钼试验

某选铁尾矿中的有用矿物主要为黄铁矿、闪锌矿和辉钼矿,主要脉石矿物有石榴石、石英、方解石等。为高效回收其中的有用矿物,实现资源的高效利用,进行了选矿试验研究。结果表明,锌、钼、硫含量分别为0.86%、0.023%、10.09%的试样采用1粗3精3扫锌钼硫混浮、1粗4精1扫抑硫浮锌钼流程处理,最终获得了锌、钼品位分别为41.53%、0.797%,锌、钼回收率分别为92.87%、67.26%的锌钼混合精矿,以及硫品位为51.75%、回收率为91.51%的硫精矿,实现了有用矿物的充分回收。     

Acid Mine Drainage at the Abandoned Kettara Mine (Morocco): 2. Mine Waste Geochemical Behavior

Weathering and humidity cell tests were used to predict the potential for acid mine drainage (AMD) and to estimate the mineral reaction rates and depletion of fine and coarse tailings from the abandoned Kettara mine, Morocco. The geochemistry of the fine and coarse mine wastes was similar and, as expected by static tests, the wastes produced significant amounts of AMD. The sulfate production rate of both fine and coarse tailings was very high (2,000–8,000 and 2,400–560 mg SO₄/kg/week, respectively) during the first weeks of kinetics tests. After 9 weeks, sulfate release became low, ranging between 600 and 78 mg SO₄/kg/week for fine tailings and 500–120 mg SO₄/kg/week for coarse tailings. Effluent water samples had low pH (2.9–4.2) and elevated concentrations of acidity, sulfate, iron, copper, and zinc. Most or all of the dissolved K, Na, Al, Mg, and Si in the AMD result from the acidic dissolution of silicates (chlorite, talc, muscovite, and albite). Fine tailings produce much higher concentrations of acidity and sulfate than coarse tailings. However, due to greater transport of oxygen and water within the coarse waste, coarse tailings could be of greater environmental significance than fine tailings. The coarse waste continued to release acid after 378 days of leaching, whereas the fine tailings naturally passivates. These laboratory results agree with field observations; the upper profile of the coarse waste rock dam is highly oxidized (75 cm) whereas oxidation in the fine tailings does not extend more than 5–15 cm beneath the surface. A comparison between weathering and humidity cell tests indicated that the general trend of dissolution of metals was essentially similar for both methods. However, sulfate depletion rates were higher for the weathering cell tests. These tests indicate that the Kettara tailings piles and dam will continue to release acid for a long time unless remedial action is taken.     

浓密法处置铀尾矿的试验研究

某铀水冶厂尾矿库,在用常规处置法运行20年后,尾矿堆积标高已达原设计标高。为了尽可能避免新建尾矿库以节省投资,提出了继续使用原尾矿库的建议。对采用常规处置法和浓密处置法延长使用原尾矿库的两种方案进行了对比,后者比前者可延长服务年限12．5年。为了给工程设计提供必要的设计依据,对浓密处置法全过程的主要环节（主要包括：尾矿浆的浓密、固体质量分数高的尾矿浆的管道输送及其排放堆积）进行了全面的现场扩大试验研究,并取得了预期的结果,为在我国铀水冶厂尽快推广应用铀尾矿浓密处置法这一新技术提供了依据。     

内蒙古某铜浮选尾渣工艺矿物学研究

以内蒙古赤峰某铜冶炼企业的铜浮选尾渣为研究对象,利用X射线衍射分析、光学显微镜、MLA矿物自动测量系统对尾渣进行较为系统的工艺矿物学分析,系统研究了冶炼渣中主要矿物物相的嵌布特征和嵌布粒度,并分析了该铜浮选尾渣的综合回收方案。结果表明,铜浮选尾渣中铁和锌的含量分别为39.75%和2.45%,渣的主要矿相为磁铁矿、铁橄榄石及玻璃相,粒度较细,单体解离度仅为32.15%。单独磁选富集磁铁矿获得高品位铁精矿的难度较大,建议采用直接还原磁选工艺进行选铁,磁选尾矿可作为水泥的原料。     

尾矿中有价矿产资源的综合回收与利用

评述有色金属和稀贵金属选矿厂尾矿中伴生矿产资源的综合回收与利用技术的研究及应用，分析尾矿中伴生矿产资源的特点，归纳尾矿综合回收与利用的方法，指出我国的有价矿产资源综合回收与利用的发展趋势。     

白钨选矿回水在高滑石钼矿选矿中的应用研究

河南某高滑石型钼铁矿采用先脱滑石后浮选钼工艺,为综合回用尾矿库白钨选矿回水、缓解该地区选矿用水紧缺的问题,对白钨选矿回水用于钼矿选矿进行了试验研究,结果表明:直接使用白钨选矿回水进行脱泥浮选,造成钼损失过大;使用白钨选矿回水磨矿后将矿浆pH值调至6,对脱泥粗精矿产品添加CF抑制剂进行脱泥精选,最终闭路试验得到钼损失率4.52%、钼粗精矿品位4.23%、回收率75.85%的良好指标,白钨选矿回水得以利用。     

尾矿库回水几种离子对铁矿石反浮选影响的研究

鞍钢齐大山和调军台选矿厂的尾矿调军台灰渣水皆排至同一个尾矿库。进一步研究表明，钙、镁、氟、硫酸根离子和砷在低浓度时对鞍钢调军台选矿厂阴离子反浮选流程选别指标基本没有影响；凤水沟尾矿库中相应组分的含量均处于低浓度范围，尾矿水返回调军台选矿厂使用，反浮选流程可正常运行。该项研究为该厂建成后使用尾矿库回水提供了科学依据。