Mine Closure Research Articles

Economic Transitions in South Africa’s Secondary Cities: Governing Mine Closures

Many South African secondary cities depend on a single economic sector, often mining or manufacturing. This makes them vulnerable to economic change and national decision-making. We describe change in three secondary cities—Emalahleni, Matjhabeng and Newcastle—all at different phases of economic transition due to imminent mine closure. We investigate the way local governance and planning are dealing with the change. We draw on concepts from institutional economics and evolutionary governance theory, material from strategic planning documents, and approximately 50 key informant interviews. We show how difficult it is to steer economic planning during economic transitions, and we demonstrate how both economic change and governance are path-dependent. Path dependency in South Africa’s mining towns has several causes: the colonial influence, which emphasised extraction and neglected beneficiation; the dominance of a single sector; the long-term problems created by mining; and the lack of the skills needed to bring about economic change. The local governments’ continuing reliance on the New Public Management paradigm, which focuses on steering as opposed to building networks, compounds the problem, along with poor governance, inadequate local capacity and inappropriate intergovernmental relations. Of the three towns, only Newcastle has shown signs of taking a new path.

Forecasting Underground Water Dynamics within the Technogenic Environment of a Mine Field. Case Study

The objective is to analyze the dynamics of the underground water of a mine field based on the study of the geofiltration process of the rock mass disturbed by mining to achieve safe extraction operations as well as subsurface territories at the stage of the mining enterprise closure. Numerical modeling, based on a finite difference method under the conditions of multifactority and definite uncertainty of processes of transformation of technogenic environment of a mine field, helps solve a problem concerning underground water dynamics forecasting. A hydrodynamic model of the M.I. Stashkov mine was developed while solving option series of epignosis problems in terms of the chronology of mine field stoping. The abovementioned made it possible to identify regularities of the history of filtration, the capacity parameters of rock mass and the expansion of areas of heightened hydraulic conductivity as well as to evaluate qualitatively the water balance components of a carbonic watered formation and an overlying one. The stage of mining closure helped obtain the forecasting hydrodynamic solutions. The efficiency of measures, concerning reduction of water ingress into mine workings and the mitigation of surface ecological effects of mine flooding was evaluated quantitatively. It was determined that implementation of the water control procedures makes it possible to perform a 10–38% decrease in water ingress. In this context, they may be applied both independently and simultaneously. In terms of mine closure and flooding, a period of complete underground water recovery takes three years; in the process, surface zones of potential waterlogging and swamping are developed within the floodplain of Samara River, located at the territory of Western Donbas (Ukraine). The scientific novelty is to define regularities of hydraulic conductivity transformation of the rock mass of a mine field starting from the mine working roof fall, up to its compaction during the mine operation period. To do that, nonstationary identification problems were solved, using numerical modeling. The abovementioned makes it possible to improve the reliability of hydrodynamic prognoses and develop technological schemes to control water at the state of the mine closure.

Indigenous forest livelihoods and bauxite mining: A case-study from northern Australia

Bauxite mining operations are increasingly sited on Indigenous-owned land, particularly in tropical areas, including northern Australia. The environmental impacts of bauxite mining are significant. Native vegetation, including commercially valuable forests, is cleared and typically windrowed and burnt. For many Indigenous Australians, mining of their land creates much concern about biocultural, community health and livelihood impacts from the loss of access to traditional lands and resources, and the ability to ‘care for country’. Improved pre-mining utilisation of forest resources and effective mine rehabilitation can mitigate some of these impacts and it is important to Indigenous communities that they are engaged in these processes. But Indigenous peoples' expectations are rarely considered or adequately addressed in site clearing activities or mine completion criteria, and there is limited guidance on how their expected outcomes can be monitored and evaluated for mine closure and relinquishment. This paper reports on a case-study of the Western Cape York Peninsula bauxite mining region in northern Australia. The paper reviews mine rehabilitation in the case-study region, including related Indigenous forest livelihoods initiatives, presents local Indigenous peoples' expectations for pre- and post-mining forest and landscape management as an integrated mining-community forestry ‘vision’, and discusses implications for mine completion criteria, mine closure and relinquishment. The findings highlight the need for Indigenous peoples' full and transparent free, prior and informed consent participation in all aspects of mine closure planning, and for further research to trial the development and assessment of mine completion criteria linked to local biocultural landscape restoration and Indigenous livelihoods. The findings can inform mining policymakers, regulators and industry professionals on the design, implementation and monitoring of mine completion criteria and associated pre- and post-mining management that will improve environmental outcomes and socio-cultural benefits for Indigenous communities impacted by mining.

Determinants of place attachment among mineworkers: Evidence from South Africa

The authors argue that, given (i) the unpredictability of the mining lifecycle and (ii) global pressure to transition out of coal, researchers must take a more critical perspective on place attachment and its consequences. Research generally depicts place attachment in a positive light. The conventional understanding is that place attachment brings stability, creates assets and helps society to take on and complete long-term projects. We use evidence from case studies to question the appropriateness of this conventional wisdom and whether it should be applied blindly in the mining industry. A policy of encouraging place attachment will be counterproductive if living standards and access to quality service provision cannot be maintained. Unchecked, place attachments can create financial lock-ins that lead to long-term economic damage. The likelihood of eventual mine closure means that policies that aim to induce place attachment to encourage stability, long-range planning and asset development may not be appropriate for all mining communities. While we agree that some measure of place attachment should be encouraged through social policy throughout the mine's lifecycle, we do not agree that place attachment should be constructed as an outcome in its own right.

Comprehensive method of assessing the flood threat of artificially drained mine subsidence areas for identification and sustainable repair of mining damage to the aquatic environment

The effects of mining, apart from surface subsidences and deformations, are forced flows of surface and underground waters, lasting many decades in the mining areas. Natural water flows should be restored by mining entities and/or their legal successors in the process of the mine closures. Such action is tantamount to a restoration of the previous state in the sense of repair of damage to the environment and surface infrastructure. Then, under natural water flows conditions, such mining areas may become flooded, often quite extensively. This paper describes a comprehensive method for flood threat assessment of artificially drained mining and post-mining areas after the restoration of natural water flows. The subject of this research is the surface of a single mine subsidence area. The term mine subsidence area (MSA) is defined as that part of the rock mass containing solid mineral deposits and the above surface affected by continuous and discountinuous deformation (as currently legally defined in terms of range and intensity). This method, together with simultaneous measurements of water levels at outflow places at the MSA boundary allows for an useful way of mapping the MSA surface. This has been developed to fully identify the true extent of mining-induced damage to the MSA aquatic environment. It introduces innovative hydromorphological elements of the MSA. These allow zoning of the MSA surface while taking into consideration future drainage works and/or projected mining subsidences inside the MSA. These spatial hydromorphological maps of the MSA identify the framework of permanent and occasional flooding and constitute the final result of this method. It is an universal tool for sustainable water management and quantitative evaluation for extraction of minerals.

Abandoned Mine Lands Reclamation by Plant Remediation Technologies

Abandoned mine lands (AMLs), which are considered some of the most dangerous anthropogenic activities in the world, are a source of hazards relating to potentially toxic elements (PTEs). Traditional reclamation techniques, which are expensive, time-consuming and not well accepted by the general public, cannot be used on a large scale. However, plant-based techniques have gained acceptance as an environmentally friendly alternative over the last 20 years. Plants can be used in AMLs for PTE phytoextraction, phytostabilization, and phytovolatilization. We reviewed these phytoremediation techniques, paying particular attention to the selection of appropriate plants in each case. In order to assess the suitability of plants for phytoremediation purposes, the accumulation capacity and tolerance mechanisms of PTEs was described. We also compiled a collection of interesting actual examples of AML phytoremediation. On-site studies have shown positive results in terms of soil quality improvement, reduced PTE bioavailability, and increased biodiversity. However, phytoremediation strategies need to better characterize potential plant candidates in order to improve PTE extraction and to reduce the negative impact on AMLs.

330-OR: Geographic Disparities and Community Context: Associations of Abandoned Coal Mine Lands with New-Onset Type 2 Diabetes in Pennsylvania

Differences in community features could help explain the geographic disparities found in type 2 diabetes (T2D). A growing literature documents that communities with abandoned industrial infrastructure, including coal mine lands with hazards such as spoil piles, open pits, and acid mine drainage, can adversely affect health through impacts on health-related behaviors and stress. We investigated the association between living near abandoned coal mine lands (AML) and new onset T2D through a case-control analysis using electronic health records from a health system in Pennsylvania. We identified cases as persons with new onset T2D (n = 15,888) and frequency-matched controls (5:1, n = 79,435) on sex, age and year of encounter. Residential addresses were geocoded using ArcGIS. We used the Abandoned Mine Land Inventory System database to obtain AML data in Pennsylvania and created variables to represent metrics of AML type and density. We performed logistic regression for each AML variable, adjusting for age, sex, race (white vs. non-white), ethnicity (Hispanic vs. non-Hispanic), and Medical Assistance (≥ 50% of time). The highest quartile (vs. the lowest) of multiple AML variables were associated (odds ratio, 95% confidence interval) with new onset T2D, including the density of physical hazards (1.20, 1.11-1.29), toxic contamination sites (1.17, 1.09-1.26), acid mine drainage impacted streams (1.12, 1.04-1.22), and the density of total mined area (1.18, 1.11-1.25). These findings contribute to the growing literature on geographic disparities in T2D. Further research is needed to investigate the physiologic mechanisms through which these associations may occur. Disclosure E. Brown: None. J. S. Pollak: None. A. G. Hirsch: None. B. S. Schwartz: None. Funding Centers for Disease Control and Prevention (DP006299); National Institutes of Health (T32HP10025)

The future of coal investment, trade, and stranded assets

The future of coal investment, trade, and stranded assets

Mining as a temporary land use: A global stocktake of post-mining transitions and repurposing

Post-mining land use and associated economies have become a priority issue in mine lifecycle planning amongst many major companies. Ensuring the post-mining landscape is returned to a safe and stable condition is usually the first order priority in mine closure, though achieving this is often a challenge. The drive for industry to do more than rehabilitation is also growing. One of the many drivers for this expectation is the scale of mines, with many mining leases occupying thousands of hectares. Some of this land may be used for other purposes with relatively little intervention. For the mine footprint itself, it is often not possible or feasible to return the landscape to the prior condition, although creative repurposing of mine features and elements of mine infrastructure may be an option. At the same time, these large-scale mines employ hundreds, sometimes thousands of people and consideration of economic transitions for mining workforces, notably local dependant populations, is increasingly expected of industry post closure, as employment is often positioned at the “heart” of development. In this article, we reframe mining as a temporary land use. This approach positions post-mining land use as intrinsic to the mine lifecycle, including the planning and operational phases. We developed a global database of repurposing cases building on the S&P Global Market Intelligence database, relevant literature and other publicly available information. We provide an overview of the findings and the themes to emerge from this global repurposing database of 141 cases. Our findings include: our general observations on the research process; an analysis of the most common repurposing land uses; factors influencing repurposing, including factors internal and external to the company; initial observations about industry approaches to repurposing. Finally, we argue that reconceptualising mine ‘closure’ and the associated mining legacies is an essential operational shift the extractives industry, notably the major companies, will need to make to keep pace with societal and local community expectation.

Using data-driven analysis of geochemical environmental information to infer the environmental impact of closed mines

River sediments have the effect of aggregating geochemical environmental information, such as that related to geological and artificial pollution resulting from mine closure. This information comprises high-dimensional data and is related to the distribution and quantities of elements in river sediments. However, accessing and interpreting this geochemical information can be difficult. This study employed a data-driven analysis that can be mathematically and statistically reduced in dimension. Using high-dimensional geochemical and environmental information on river sediments, this study evaluated the environmental impact of closed mines. Sample for analysis were collected from three rivers. There are differences in the existence of mines and mine wastewater treatment methods in this river. A total of 33 elements were measured in river sediments. Frequency distribution analysis and Principal component analysis revealed that the elements had unique distribution and frequency characteristics in each river catchment. Four environmental factors could be extracted from the relationship of elements due to lower dimension. PC1 was influenced by the land use in the river area. PC2 captured the geological background. PC3 captured the mixing-diluting effect that occurs in rivers. PC4 effectively captured the effects of domestic wastewater and the effects of closed mines. The effects of the closed mines could be confirmed using the PC4 score for the Okawa River and the Akagawa River. By examining the elemental relationships obtained using these mathematical methods, it is possible to infer the effect of geological features and mines on sediment physiochemistry using existing data on river sediments.

Sinkhole Hazard Caused by Inactive Mining Shafts as Illustrated by a Selected Example

Loss of stability of shafts liquidated in the past is a frequent cause of sinkhole creation on the surface. This manuscript presents such a case study. The sinkhole was created shortly after intense rainfall, so it can be assumed that displacement of the rock material in the shaft took place, i.e. the phenomenon of suffusion. One of the research aims was to confirm the assumption about the displacement of rock material filling the shaft on the basis of selected methods of sinking forecasting. Ex post forecast sinkhole creation was conducted using two methods (Bell and finite element method). It was assumed that the material filling the shaft lowered itself to a height determined on the basis of the sinkhole and shaft dimensions. Both methods gave the same results, consistent with the literature . The manuscript also presents a short overview of technologies used for decommissioning shafts and assesses their effectiveness in terms of preventing sinkhole creation. These methods have been used since the nineteenth century until present times. Considering the suffusion phenomenon, the paper proposes a way to drain rainwater from the shaft area, which was another purpose of the work. The necessity to find and verify the ways to secure decommissioned shafts from water is indicated as an important future direction of research.

FEM for prediction of surface deformations induced by flooding of steeply inclined mining seams

The closure of coal mines is closely linked to the change in European energy policy regarding the reduction of CO2 emissions. The process of closing underground mines has impacted many mining companies, especially in Europe. Along with the decision to close a mine, a number of steps have to be taken with regard to its liquidation. One of these is the decision to begin flooding the mining excavations with underground water. The process of liquidation of an underground mine brings with it a number of problems and dangers related to, among others, the environment, geomechanics and surface protection.This article aims to present the possibility of forecasting deformation of the land surface as a result of the flooding of underground excavations characterised by steeply inclined seams and to indicate the dangers posed by the liquidation of underground mines to the environment and civil engineering structures. The use of numerical modelling is an innovative approach to the problem of steeply inclined flooded seam induced surface deformations. It is an interdisciplinary area that encompasses mining and environmental protection.The authors present numerical calculations and simulations of land surface uplift resulting from the liquidation process for a case study (Spanish mine). The calculations were made by Finite Element Modelling (FEM). The authors have created numerical models characterised by steeply inclined seams, and based on the authorship methodology they have calculated the surface deformation. The obtained results were verified by measurements. Such analysis was never done before. The authors proved that with numerical modelling and developed methodology, it is possible to successfully forecast surface deformations during the liquidation of mines by flooding. Then, based on the obtained forecast values, a discussion on the possibility of mining damage in the analysed area may begin. Such damages have been observed during the flooding of German mines.The conducted research is interdisciplinary in the field of mining and civil and environmental engineering. Furthermore, the very issue of damage is also important from the socio-economical point of view.

Rendering mine closure governable and constraints to inclusive development in the Andean region

Although the early stages of mining are often associated with promises of socioeconomic development based on economic growth, limited oversight of mine closure practices has tended to deliver lingering social, economic, and environmental problems across the Andean region. New and revised legislation, policies, and regulations that address mine closure in the region demonstrate what I argue are attempts to render mine closure governable—that is, the circumscribing of mine closure as an ‘intelligible’ and strictly technical problem, amenable to state intervention, without challenging existing bureaucratic processes or political economic structures. Such narrow framings of mine closure exclude possibilities for local consultation and participation, and, by extension, hinder the relationship between mine closure and a more socioeconomically inclusive and less environmentally damaging form of post-mine development. I outline discrete attempts to make mine closure more easily governable in the Andean region, with detailed focus on the cases of Colombia and Chile, and show that this process also tends to render local populations invisible. I point to the conspicuous disconnect between high hopes for mining's contribution to Andean states' economic growth and concrete possibilities for post-mine development based on ideas of equity, inclusion, and social justice. I conclude by pointing to the need for legal and regulatory institutions in the Andean region that more actively facilitate the creation and distribution of benefits, services, and livelihood opportunities following mine closure.

Discussion on Some Topical Issues of Water Prevention and Control in Coal Mines

Effective prevention and control of water hazards in China’s coal mines require that several key issues be addressed. The key issues discussed in this paper are the complex and variable water inrush types in mines, uncertainties in calculation of mine inflow, and the primary mechanism of water hazards resulting from mining-induced bedding separation. Challenges encountered in reinforcement and grouting of the seam roof and floor are also discussed, as well as the risks posed by mine closure. We suggest research areas to better predict and understand the impacts of these issues and propose a direction for improvement of coal mine water control.

Application of Water Quality of pH and TSS Monitoring Using Online Monitoring at Settling Pond of Coal Mining Company PT XY

The existence of an Online Monitoring System is very important to know in real time the changes in water quality at Settling Pond so that it can immediately take action to maintain the quality of water from the settling pond always comply with the required environmental quality standards without errors resulting in mine closure and criminal sanctions. To face this challenge, a system needs to be developed that can monitor real time output water settling ponds, so that early warning can be provided if the settling pond requires special handling, to the team in charge. Currently water quality monitoring is still done manually, namely by doing water sampling and quality testing manually. This stage uses at least 12 teams to supervise 18 active, controlled settling ponds 24 hours and 7 days a week. In the implementation there were quite a number of challenges faced, apart from the fact that the Settling Pond location was quite far away so that it took quite a long time to reach the location. The applicable laws and regulations state that mine water management must not exceed the required environmental quality standard (BML) so that fast information is needed to be able to know water quality. Keywords: Online Monitoring System, Water Quality DOI: 10.7176/JIEA/11-2-03 Publication date: April 30 th 2021

Mapping Potentially Acid Generating Material on Abandoned Mine Lands Using Remotely Piloted Aerial Systems

Weathering and transport of potentially acid generating material (PAGM) at abandoned mines can degrade downstream environments and contaminate water resources. Monitoring the thousands of abandoned mine lands (AMLs) for exposed PAGM using field surveys is time intensive. Here, we explore the use of Remotely Piloted Aerial Systems (RPASs) as a complementary remote sensing platform to map the spatial and temporal changes of PAGM across a mine waste rock pile on an AML. We focus on testing the ability of established supervised and unsupervised classification algorithms to map PAGM on imagery with very high spatial resolution, but low spectral sampling. At the Perry Canyon, NV, USA AML, we carried out six flights over a 29-month period, using a RPAS equipped with a 5-band multispectral sensor measuring in the visible to near infrared (400–1000 nm). We built six different 3 cm resolution orthorectified reflectance maps, and our tests using supervised and unsupervised classifications revealed benefits to each approach. Supervised classification schemes allowed accurate mapping of classes that lacked published spectral libraries, such as acid mine drainage (AMD) and efflorescent mineral salts (EMS). The unsupervised method produced similar maps of PAGM, as compared to supervised schemes, but with little user input. Our classified multi-temporal maps, validated with multiple field and lab-based methods, revealed persistent and slowly growing ‘hotspots’ of jarosite on the mine waste rock pile, whereas EMS exhibit more rapid fluctuations in extent. The mapping methods we detail for a RPAS carrying a broadband multispectral sensor can be applied extensively to AMLs. Our methods show promise to increase the spatial and temporal coverage of accurate maps critical for environmental monitoring and reclamation efforts over AMLs.

Women and mine closure: A case study of policy in South Africa

The social aspects of mine closure remain a challenge to the mining industry. Its tendency to deal with problems towards the end of a mine's life cycle, rather than planning for them from the start, is partly responsible for the gendered impact of mine closure. Using documentary evidence, the literature on how mining affects women, and the history of discrimination against black women in South Africa, we examine South African policy on women in mining and how mine closure affects them. The paper contributes towards a more nuanced understanding of the social aspects of mine closure. We recommend a more comprehensive policy focus on the local and regional social consequences of mine closure for women.

Groundwater Risk Assessment in the Context of an Underground Coal Mine Closure and an Economic Evaluation of Proposed Treatments: A Case Study

Mining companies are responsible for the impacts that result from their mining activities even after the mining period has ended. At the same time, at the European and international levels, there is a lack of a detailed operational methodology comprising environmental risks during and after closure of underground coal mines. The environmental risk aspects that need to be considered when planning the closure of an underground coal mine and post closure in the broader environmental context are the following: modification of water flow scheme, surface instability, mine gas emission on the surface, and water and soil pollution. In this study, we focus on assessing groundwater risk in the context of an underground coal mine closure and evaluating the selected risk mitigation strategies in terms of performance and cost. The results from this study could be used for developing a final closure groundwater assessment plan by selecting the most feasible treatment alternatives for different environmental impacts, together with the transitional monitoring that could guarantee a hazard level in compliance with land reuse and the use of natural resources. Finally, the cost-efficient monitoring and treatment programs are used to estimate the financial provisions needed to mitigate groundwater risks during underground coal mine closure contexts.

Identifying industry practice, barriers, and opportunities for mine rehabilitation completion criteria in western Australia

Around the world, the development of acceptable and achievable completion criteria is a necessary part of mine closure planning and fundamental to the successful transition of mined land to a post-mining use. Without adequate completion criteria, a mining company cannot proceed to the process of relinquishment, which is the ultimate goal of most mine closure processes. Despite the central role of completion criteria, there is still a need to build capacity and understanding of how to set targets and develop measurable completion criteria that are accepted by all stakeholders involved.We investigate how completion criteria are currently developed in one of Australia's major mining jurisdictions: Western Australia. Through an industry consultation process that involved interviews and a survey with a total of 102 participants from mining companies, consulting businesses, and relevant regulators, we highlight key challenges and opportunities that the sector faces to successfully define clear, achievable, and agreed completion criteria.This is one of the few industry-wide investigations to capture and analyze the perspectives of stakeholders involved in writing and assessing mine closure completion criteria. Results show that some major challenges included inconsistent coordination within and between stakeholder groups, a lack of knowledge or data about restoration, and an overreliance on status quo practices and post-mining land uses. Our work shows that ongoing research on ecological restoration and technological innovations is necessary, but that additional organizational and regulatory barriers need to be addressed to achieve a consistent, coordinated, multi-stakeholder approach to define completion criteria and to advance successful mine rehabilitation and relinquishment.

Phytostabilization of acidic mine tailings with biochar, biosolids, lime, and locally-sourced microbial inoculum: Do amendment mixtures influence plant growth, tailing chemistry, and microbial composition?

Abandoned mine lands present persistent environmental challenges to ecosystems and economies; reclamation is an important step for overcoming these challenges. Phytostabilization is an elegant and cost-effective reclamation strategy, however, establishing plants on severely degraded soils is problematic, often requiring soil amendments. We evaluated whether amendment mixtures composed of lime, biochar, biosolids, and locally-sourced microbial inoculum (LSM) could alleviate the constraints that hinder phytostabilization success. We hypothesized that 1) plants grown in tailings amended with lime, biochar, and biosolids (LBB) would establish faster and grow larger than plants grown in tailings amended with lime only, and 2) the LSM source would influence microbial community function and structure in amended mine tailings. We conducted a greenhouse study that simulated in situ conditions to measure the influence of LBB-LSM amendment blends on plant growth, plant nutrients, metal concentrations, microbial function, and microbial community structure. Blue wildrye [Elymus glaucus Buckley ssp. Jepsonii (Burtt Davy) Gould] was grown in tailings collected from the Formosa mine site amended with various combinations of LBB-LSM. The above and belowground biomass of plants grown in mine tailings amended with LBB was 3 to 4 times larger than the biomass of plants grown in tailings amended only with lime. Although the LSM addition did not influence immediate plant growth, it did affect nutrient content and altered the rhizosphere community composition. As such, it is not yet clear if LSM-driven alterations in microbial membership will advance mine reclamation strategies by improving long-term growth.