Completion criteria - Case studies considering bond relinquishment and mine decommissioning: Western Australia

ABSTRACT

The Western Australia Government Agencies controlling environmental bond assessment and land relinquishment after mine decommissioning advocate proactive environmental management. Meeting environmental objectives ensures return of bond monies and facilitates release of the Company from environmental obligations. Completion criteria that confirm establishment of a self-perpetuating and resilient vegetation cover over mine waste are being developed. Post-mining land use generally reverts to maintaining the natural ecosystem or rangeland. Within this climatic zone very distinct vegetation communities are closely linked to soil substrate classification. Matching surface waste characteristics from a mine waste dump with those of surrounding analogue communities is the first step in determining an achievable vegetation cover. Examples of the methodology as applied to one Western Australian mine site, a semi-arid location (annual rainfall 320?mm) (Westonia - 31°18'S, 118°42'E) is presented. There has, at Westonia, been establishment of Eucalypt Woodland on mildly saline waste surfaces. The combination of direct seeding at the appropriate sowing time and good topsoil management, has led to successful revegetation of a suite of species with all life forms represented.     

Mapping of soil nutrients in an abandoned Chinese coal mine and waste disposal site

The present paper attempts to identify the spatial patterns of soil nutrients in the abandoned Haizhou opencast coal mine and waste disposal site, in China. A geostatistical approach was used to overcome problems due to the heterogeneity of the site (some parts have been abandoned for more than 30 years, lack of clean soil, presence of overburden and low-grade ore, co-disposal of wastes from adjacent sites) and the limited number of available samples. One hundred and eight soil samples were collected from an area of 332 ha and analyzed for pH, organic matter (OM), NH₄–N, available phosphorus (AP) and available potassium (AK). The results indicate that nutrients exhibit different spatial distribution and only NH₄–N showed strong spatial dependence and a relatively large nugget effect. Relatively high content of OM, NH₄–N, AP and AK was seen in the northeastern part, whereas pH was higher in central north and southern parts of the site. The determination of the spatial variability and heterogeneity of nutrients in mining and waste disposal sites assesses the need for amendments and assists in the selection of the most feasible revegetation scheme.     

矿山地质环境治理与土地复垦可行性研究

为了使研究内资源得到合理利用,为矿山地质环境保护治理及土地复垦的实施管理提供依据,研究了矿山地质环境治理与土地复垦可行性,对技术可行性和经济可行性进行了分析,复垦区土地利用现状、土地复垦适宜性评价、矿区土地复垦可行性分析等。并对其治理技术进行了研究,生产期对露天采场、矿山道路可剥离表土区域进行表土剥离,在露天采场、工业场地外围设立崩塌、滑坡警示牌,露天采场上游开挖截水沟;在表土场下游设置浆砌石挡土(渣)墙,上游设置排水渠,外围设立滑坡、泥石流警示牌。结束后,在露天采场台阶外侧修筑了浆砌石挡土墙,进行场地平整,植被重建工程;基底平台外侧修筑了浆砌石挡土墙,土壤回覆,植被重建工程;对表土场、工业场地进行了砌体拆除、边坡修整、土壤回覆、植被重建工程;对矿山道路进行了植被重建工程等。     

Assessing various rehabilitation strategies for coarse coal washery reject dumps in the Hunter Valley,Australia. I. Chemical characteristics

At several coal mines in the Hunter Valley (New South Wales, Australia), the use of coarse coal washery reject (chitter) as a top-dressing material has resulted in successful establishment rates of tree and shrub species by direct seeding. However, concerns have arisen about the potential to downgrade the rural capability of the land for grazing, poor understanding of the material's long-term benefits, and spontaneous combustion issues. To ascertain the suitability of chitter as a final landform surface, a revegetation research trial was initiated at United Collieries coal mine in the Hunter Valley of New South Wales. Experimental plots were established in autumn (May 1998) and spring (November 1998) on a freshly shaped stockpile of chitter. The revegetation trials incorporated four substrate treatments, namely a 1?m and 20?cm capping of overburden, a 20?cm topsoil dressing and a treatment of only chitter. Each of the four substrate treatments incorporated five revegetation treatments, namely pasture species and mulch (straw), pasture species and no mulch, native seed (shrub and tree) and mulch, native seed and no mulch, and planted tubestock trees. Chemical characteristics (pH, EC, total N, nitrate-N, available-P, total P, total S, Ca, Na, Mg, K, organic C and soil moisture) across the substrate and vegetation treatments were assessed at 0, 3, 6 and 12 months after establishment.

Laboratory analyses of soil samples from the autumn and spring substrate sowings concluded that the chitter treatment contained a significantly higher concentration of organic carbon (23 – 41%), Na (2.8 – 13 me/100g), total N (2600 – 5300?mg/kg) and S (900 – 4000?mg/kg), and pH was elevated (7.5 – 9.8), relative to the other substrates. The topsoil substrate had significantly greater moisture content and more nitrate-N in comparison to the overburden and chitter materials, and exhibited a significantly lower pH over time. The two overburden treatments showed similar chemical properties and contained significantly higher levels of available P relative to topsoil and chitter. In comparison to recommended levels, all substrates recorded adequate levels of Ca, Mg and K across the autumn and spring assessments and were generally deficient in nitrate-N. In the overburden materials, levels of organic carbon, electrical conductivity, exchangeable bases, total P and available P were generally adequate. However, the pH (8.1 – 8.9) and S (200 – 700?mg/kg) content of overburden was consistently high, and deficiencies in total and available nitrogen were commonly detected. Assessment of substrate samples across vegetation treatments showed few differences with only K, available P and nitrate-N varying significantly between treatments. In both the autumn and spring trials, the concentration of available P in pasture plots was significantly higher in comparison to the other vegetation treatments, while K levels were significantly higher in the pasture and mulch treatment relative to tubestock plots. This probably resulted from greater uptake of these nutrients by trees and shrubs compared to pasture species. In the autumn trials, seeded native tree plots contained significantly more nitrate-N than the other treatments, probably due to N-fixation by Acacia spp. Across both establishment seasons, topsoil provided the best chemical substrate for the establishment of vegetation and chitter was deemed the least hospitable substrate, while the different vegetation treatments appeared to have little effect on the chemical characteristics of the substrates. Vegetation characteristics across the treatments are presented in an accompanying paper (Charnock and Grant, Assessing various rehabilitation strategies for coarse coal washery reject dumps in the Hunter Valley, Australia. II. Vegetation characteristics. International Journal of Surface Mining, Reclamation and Environment, 2005 (in review)).     

洛阳市龙门山废弃露天矿山地质环境影响评价及修复研究

洛阳市龙门山生态修复区位于风景秀丽的龙门石窟景区东,近年来矿山开采活动,对龙门山造成了一系列的矿山地质环境问题。洛阳市坚决贯彻习近平总书记生态文明思想,牢固树立“绿水青山就是金山银山”的理念,开展废弃露天矿山地质环境修复。本文通过对研究区开展矿山地质灾害、含水层破坏、地形地貌景观破坏及土地损毁等矿山地质环境影响评价,划分了矿山地质环境恢复治理分区,讨论了矿山地质环境修复措施。结果表明：研究区矿山地质灾害危害程度小,对含水层影响小,地形地貌景观和土地资源破坏严重;矿山地质环境恢复治理区域划分为重点防治区、次重点防治区和一般防治区,其中重点防治区面积6.47hm2^,次重点防治区9.73hm2^,一般防治区面积20.15hm2^,针对评价成果研究区采用“坡面危岩清理+地形地貌重塑+土壤重构+挡土墙+截排水渠+植被重建”等修复治理措施。研究成果对同类型露天矿山的地质环境影响评价及修复研究具有一定的借鉴意义。     

Analyses of environmental impacts of underground coal mining in an arid region using remote sensing and GIS

The influences of coal mining in an arid environment on vegetation coverage, land-use change, desertification, soil and water loss were discussed. A series of available TM/ETM+ images with no cloud cover from July/August in different years (1990, 1995, 2000 and 2005) were used to analyze the change in various land environmental factors over time. The results show that while mining activity initially had a marked adverse impact on the environment, mine rehabilitation measures have also subsequently played a great role in improving vegetation cover and controlling land desertification and loss of water and soil. The effect of coal mining on vegetation cover is dependent upon the soil type and natural indigenous flora. Results of this investigation imply that mining activity has a greater effect on the vegetation of loess areas than at sandy sites. Although local vegetation coverage was improved by planting in the mining area, the total area of land affected by desertification still increased from 26.81% in 1990 when large-scale mine construction was introduced, to 46.79% in 1995. With continuous efforts at rehabilitation, the vegetation cover in the Shendong coal mining area was increasing, and loss of water and soil were effectively controlled since 1995. Subsequently, the total area of extreme desertification decreased to 23.24% in 2000 and further to 18.68% in 2005. The total area affected by severe loss of water and soil also decreased since the early 1990’s (70.61% in 1990, 71.43% in 1995), to 43.64% in 2000 and 34.93% in 2005, respectively.     

Arsenic in mine tailings - the Chimo Mine case study

ABSTRACT

Arsenic is an element frequently associated with mining operations around the world. Its long-term stability in mine tailings may be a problem due to its particular chemical properties. It has been frequently observed that arsenic goes into dissolution at conditions where other metals are stable. This paper presents a case study of a tailing site where arsenic has been periodically released. Data collected over a three-year period are presented and analysed. The paper identifies the causes underlying the periodic arsenic release and defines the treatment methods in order to correct the situation.     

马圈沟矿区生态环境恢复与治理应注意的问题

新疆现有小型煤矿数量较多，近年来通过整合、关闭了大批小型矿井，为改善区域生态环境、减少水土流失、消除地质灾害，乌鲁木齐县政府通过财政拨款方式对马圈沟矿区关闭小煤矿进行生态恢复治理，根据矿区所处区位，采用“建筑物、硬化层拆除→高危区处理→场地平整→黄土覆盖→沉陷区治理→植被恢复→设围栏和警示牌进行封育→抚育”等措施，对马圈沟矿区进行生态恢复，目前已通过验收，实现矿区生态环境的美化和良性转化的目标。     

The composition of soil fungi occurring on reclaimed areas of the McKinley coal mine

ABSTRACT

The soil fungal community was evaluated on an undisturbed soil and compared to three reclaimed coal mine spoils of varying age. Significantly higher fungal propagules and higher diversity were found in the most recently reclaimed spoil site (1-year-old)than in the two older reclaimed areas (6 and 11 years old) or the undisturbed soil. The markedly higher diversity occurring in the 1-year-old site as compared to the undisturbed soil was attributed to using fresh topsoil during the reclamation procedure, rather than using topsoil that had been stockpiled. On the other hand, the two older reclaimed areas contained fungal populations and diversity equal to the undisturbed soil. Although, populations and diversity in the two older reclaimed areas were equal to the undisturbed soil, the types of fungal groups isolated (mainly secondary species) were vastly different from the undisturbed soil.     

Determination of suitable plant species for reclamation at an abandoned coal mine area

This study was conducted to determine suitable plant species for reclamation of an abandoned coal mine area at Ovacik village within the borders of Yaprakli town in the province of Cankiri, Turkey. The paper comprises three basic parts: (i) sampling and analyses of several chemical–physical properties of the soil; (ii) sampling and identification of the natural plant species; and (iii) determination of topographic features of the study area by spatial analysis tools. Soil samples were taken from 0 to 30?cm depth at 15 sampling sites. Soil textural separates (percent sand, silt and clay), calcium carbonate (CaCO₃), soil pH, electrical conductivity and soil organic matter (SOM) were measured. Soil properties, especially SOM content, pH and textural separates, exhibited significant variations at the sampling site. SOM content was considerably high and pH was low in the coal storage area. The plant composition of the study area was studied based on the plants collected during the period of vegetation from 2010 to 2011. The collected plants were suitably transformed to herbarium materials and identified according to modern systematic techniques. A total of 54 taxa belonging to 23 families were determined in the study area. The average slope of the study area is approximately 24% and the dominant aspect is south-east. By considering all features of the study area, a total of 28 taxa, excluding natural plant species identified on the site, were suggested for reclamation.     

Economic feasibility of introducing trolly assisted haulage to an Australian open pit mine

ABSTRACT

The paper presents results of the study which evaluated feasibility of introducing a trolley assisted haulage system to an Australian open pit mine. The study compared expected performance of the trolley system, an updated version of the systems used in several South African mines, to that of the fleet of mechanical drive trucks used by the mine at present leading to definition of site specific conditions under which the trolley system may become economically feasible.     

关闭矿山生态修复植物选择与施工技术

矿山的过度开采会加速水土流失、降低植被存活率,导致矿山区域生态环境变差,急需进行矿山区域生态环境修复。提出了关闭矿山生态修复植被选择与施工技术,分析矿山区域的地层岩性及水文地质,获取土壤有机物质的性质指标,分析了土壤物质的总体含量会对生态环境修复效果的影响。根据分析结果,选取不同种类的植物指进行调查、筛选测试,得到适应力强、成活率高、覆盖率广的植被,实现生态修复植物的选择。以修复植物选取结果为基础,对矿区的道路、边坡、生产环境等进行治理防护,完成关闭矿山生态修复植物的选择与施工技术研究,改善了矿区生态环境。     

Distribution pattern and limiting factors of vegetation in coal waste pile of Xinzhuangzi coal mine in Huainan

In China, coal mine spoils have traditionally been dumped in cone-shaped heaps that have the potential to pollute air, soil and water environments. The coal waste pile occupies lots of arable land and endangers the ecological system in the coal mine district. Vegetation restoration is an efficient approach for controlling the environment pollution of coal waste pile, and is also a topic of current interest in restoration ecology and degradation system ecology. This study focused on the distribution pattern and limiting factors of vegetation in coal waste pile of Xinzhuangzi Coal Mine in Huainan. The results show that two stable plant communities (Synodon dactylon+Erigeron bonariensis.L+Setaria viridis community and Humulus scanden+ Erigeron bonariensis. L community) exist at the bottom of the pile. Synodon dactylon and Erigeron bonariensis. L have much higher values of summed dominance ratio, which denote that these two species can be used for restoration of coal waste piles. The high levels of pH (8.77) and salinity, low levels of total P and total K in coal mine spoil can be the limiting factors for the residence and growth of vegetation.     

我国矿区生态恢复制度几个问题及改进建议

分析了我国矿区生态恢复制度存在的问题，从恢复生态学的观点重新阐述了矿区复垦和生态恢复的概念、基本原则和主要内容；指出我国矿区复垦土地应从优先用于农业转变为恢复自然生态系统与农业并重，在管理上应从部门交叉管理、重复收费、政府组织复垦的模式转变为政府协调、监督下的企业自行恢复的抵押金制度。     

三友石灰石矿生态重构孔栽植被土壤环境监测系统研究

通过采用传感器技术、数据采集及处理、数据传输等技术手段,对工程重构区域采用的工程措施的植被恢复土壤环境进行数据采集技术设计及应用,并对植被生长情况进行定期采集分析,指导后期山区采矿迹地项目进度安排与规划设计。以三友石灰石矿迹地生态重构地植物生长监测为研究对象,结合燕山地区该矿实际,开展生态重构监测。获取了石灰岩矿山山体断面上不同区域的孔洞内土壤的温度和含水率信息,对促进采矿迹地生态恢复稳定持续、改善整体生态环境有着重要的指导作用。     

Underground placement of coal combustion products in central Illinois: A case study

Abstract

Placement of coal combustion products into abandoned sections of underground coal mines for the purpose of subsidence mitigation has been investigated in Illinois. Several handling and transportation systems have been examined. Prototype pneumatic and hydraulic placement systems have been developed and demonstrated. The demonstration site, Peabody No. 10 mine in Pawnee Illinois, is selected as a case study. It is found that, for a project of 5 years, transporting 150,000 tons of product annually from a power plant located 32 km (20 miles) to the mine would cost $2.00 per ton and placement into underground would cost $3.07 per ton.     

生态学在露天煤矿排土场生态恢复中的应用

以黑岱沟露天煤矿为例,对矿区工程复垦后土地生物复垦中的土壤改良、植被品种的筛选和植被工艺等理论与技术方面的问题进行了研究。明确了复垦区的土壤性质,运用生态学原理,采取了恰当的土壤改良措施,并有选择地种植了合适的物种,快速地恢复了矿区植被,从而有效地控制了水土流失,改善了矿区的生态环境,也促进了矿区农业、林业、畜牧业的平衡发展。     

Assessment of the Impact of Irrigation with Low-quality Mine Water on Virgin and Rehabilitated Soils in the Upper Olifants Basin

Low-quality mine water from collieries may be used in large quantities to irrigate agricultural crops on virgin (unmined) and rehabilitated soils in South Africa. Such a use could enhance crop production and allow environmentally sustainable mine water disposal. In this study, the volume and qualities of the runoff from two centre pivots irrigated with moderately saline mine water, as well as their soil water salinities, were monitored and used to determine water and salt balances, using the modified ACRU agrohydrological model, ACRU2000, and its salinity module, ACRUSalinity. At both sites, much of the water evaporated, while a significant part of the salt input either precipitated or remained with the water in the soil horizons. A higher percentage of drainage water (and salinity) were retained as ground water storage and a lower percentage of runoff occurred in the rehabilitated sandy loam soil, while a higher percentage of salts accompanied runoff in the virgin clayey soils. Simulated salt saturation values indicate that many crops could be successfully irrigated at 100% yield potential at either site. Electrical resistivity surveys were carried out at both sites. A general decrease in resistivities with depth in both the virgin and rehabilitated soils reflected the decreasing influence of the mine water used for irrigation with depth and the precipitation of salts in the soils close to the ground surface. The occurrence of a thicker, low-resistivity, near-surface layer near the exit of each pivot area indicates that the water and salt content of the subsurface increased in the direction that the surface and near-surface irrigation water flowed. An erratum to this article can be found at     

金家渠煤矿多污染物有效处置技术集成及应用

针对推动矿井水利用,金家渠煤矿建立矿井水动态监测机制,应用“高效沉淀澄清+超滤+反渗透”矿井水分级提标处理技术及“A/O生化处理+瓷砂/生物活性炭过滤+二氧化氯消毒”生活污水处理工艺,构建了矿井水资源综合利用体系;针对锅炉烟气多污染物治理,采用“PNCR脱硝+陶瓷多管预除尘+DMCD低压脉冲长布袋除尘+高效喷淋雾化脱硫(氧化镁法脱硫)”工艺,实现了达标排放;针对煤矸石堆积场地,采用煤矸石充填、分层碾压、覆土绿化治理以及“草灌+乔灌+林草”模式进行生态系统植被修复。通过对矿井水、烟气、煤矸石的有效处置,有效修复了矿区生态系统,使当地水源得到涵养,为矿区可持续发展打下了坚实基础。     

Tailings revegetation - on non-ameliorated substrate

ABSTRACT

The Westonia open pit gold mine, 320 km east of Perth, Western Australia (31°18'S, 118°42'E) was decommissioned in July 1991. Normandy Mining Pty Ltd seeded in May-June I993, the entire surface of the tailings storage facility. The rehabilitation objective was to stabilise the tailings structure. Tailings slurry had been pumped into three Cells at different periods throughout mining operations. The near surface layer of tailings is most significant from a rehabilitation perspective, as it is where plants are growing. Vegetated areas have lower salinity than areas lacking vegetation (8.23 compared with 47,39 dS m^?1 ECe). Revegetation density averages 1.734 stems m^?2 in October 1999 and foliage cover is 30%. Nine chenopods were recorded in October 1999 with Maireana brevifolia, Atriplex undulata and A. leniiformis more prevalent. Grasses continue to show accelerated establishment. A cryptogamic cover prevalent over the upper surfaces of ‘raw’ tailings appears to be enhanced under established vegetation where moisture levels and the soil nutrient status are inherently higher. The tailings profile in the centre of the third cell (vegetation absent) showed similar changes in salinity to previous samplings. The surface sample in April 1999 (102 dS m^?1) was less saline than the April 1998 sampling (225 dS m^?1). The layer between 0.1 m and 0.4 m remains extremely saline, i.e. range 83-150 dS m^?1 ECe. Around the perimeter of his cell the tailings is coarser, and sampling of the profile to 0.3 m depth gave salinities from 5 to 20 dS m^?1 ECe.