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1

Evaluating the post-mining land uses of former mine sites for sustainable purposes in South Africa

Mhlongo Sphiwe E.

Journal of Sustainable Mining

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2023

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Vol. 22. iss. 2

110--127

EN

This paper uses a case study of an abandoned magnesite mine in the Limpopo Province of South Africa to ﬁnd ways of identifying post-mining land used from the current uses of the abandoned mine sites or features. The approach used involved carrying out a ﬁeld characterization of the mine site and documentation of the current uses of the features of the abandoned mine site. The technique used to identify the internal and external factors of the land uses involved analyzing their Strength, Weakness, Opportunities, and Threats. The Analytic Hierarchy Process (AHP) technique was used for further ranking of the land uses to identify the most post-mining or rehabilitation land uses for the different parts of the mine. Lastly, the earthwork requirement in reshaping the terrain of the mine to support the selected land uses was estimated from the 3D-terrain models generated from height data collected using a Real-Time Kinematic Geographical Positioning System. The results of the study identiﬁed land use that needs further surface development as the most appropriate for the abandoned Nyala Mine. These land uses demonstrated the potential of addressing the hazards of the mine with the clear promise of improving the socio-economic status of the host communities.

2

The influence of pressure drop on gas emissions from a mining shaft - an overview

Wrona Paweł, Różański Zenon, Pach Grzegorz, Niewiadomski Adam, Suponik Tomasz

Journal of Sustainable Mining

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2021

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Vol. 20, iss. 1

20--27

EN

Climate change can make an impact on the mining sector and post-mining sites. Among others, extreme weather events are connected with sudden and deep pressure drops which lead to gas emissions from an underground space to the surface through closed shafts. The tests undertaken in the frameworks of TEXMIN project lead to get measuring data of this phenomenon and will allow validating numerical models for further forecasts and mitigation means. Three examples of the results were presented. They showed that the intensity of pressure drop influences strongly on gas emissions from a closed shaft. Although the pressure drop process should be investigated in detail considering hourly or even more frequent variations of pressure. Considering the variation of emitted gases in the vicinity of the closed shaft they remained increased even 20-30 m from the point of emissions.

3

Investigation of Groundwater Flow Using Δ18O and ΔD in a Sulfur Mine in Japan

Matsumoto Shinji, Machida Isao

Inżynieria Mineralna

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2020

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no. 1, vol. 2

115--120

EN

The A sulfur mine is located in the Iwate Prefecture of Japan. This mine has both surface and underground parts and was operated from the late 1800s to the late 1900s. Since the early 1900s, acid mine drainage (AMD) has been reported in this mine, and the waste water has been neutralized in a treatment plant since the mine was closed. Recently, reducing the AMD volume by decreasing water inflow to the underground mine has been considered as a way to reduce the AMD treatment cost. The first step in such an approach is to understand in detail the groundwater flow around the mine. However, part of the study area is covered by lava and comprises crystalline rocks with complicated structures, making it difficult to understand the groundwater flow. Therefore, the present study investigated the groundwater flow around this mine by focusing on water quality, such as pH and electrical conductivity (EC), stable isotopes (i.e. δ18O and δD) and 3H in the surface and ground water. The spatial distributions of pH, Stiff diagrams, and δ18O and δD values in the surface and ground water indicated that the groundwater flow system was divided into three basins in the study area, as predicted from geomorphological information. Moreover, the spatial distribution of δ18O and δD in the surface and ground water suggested that the groundwater recharged at the highest altitudes in the B mountain in the northwest of the mine might flow in the underground mine. Furthermore, the 3H values in the waste water discharged from the underground part of mine implied that the groundwater age was no more than approximately 60 years old.

PL

Kopalnia siarki znajduje się w prefekturze Iwate w Japonii. Kopalnia ma zarówno części naziemne, jak i podziemne i działała od końca 1800 roku do końca XX wieku. Od początku XX wieku odnotowano w tej kopalni kwaśny drenaż kopalniany (AMD), a ścieki były zneutralizowane w oczyszczalni do czasu zamknięcia kopalni. Ostatnio uznano, że zmniejszenie objętości AMD przez zmniejszenie dopływu wody do podziemnej kopalni jest dobrym sposobem na zmniejszenie kosztów neutralizacji AMD. Pierwszym krokiem w takim podejściu jest szczegółowa analiza przepływu wód gruntowych wokół kopalni. Jednak część obszaru objętego badaniem jest pokryta lawą i obejmuje skały krystaliczne o skomplikowanych strukturach, co utrudnia zrozumienie przepływu wód gruntowych. Dlatego w niniejszych badaniach określono przepływ wód podziemnych wokół tej kopalni, koncentrując się na jakości wody, określono parametry takie jak pH i przewodność elektryczna (EC), stabilne izotopy (tj. Δ18O i δD) oraz 3H w wodzie powierzchniowej i gruntowej. Przestrzenne rozkłady odczynu pH, wartości δ18O i δD w wodzie powierzchniowej i gruntowej wskazały, że system przepływu wód podziemnych został podzielony na trzy baseny na badanym obszarze, zgodnie z przewidywaniami z informacji geomorfologicznej. Ponadto rozkład przestrzenny δ18O i δD w wodach powierzchniowych i gruntowych sugerował, że wody gruntowe dopływające na najwyższych wysokościach w północno-zachodniej części kopalni mogą płynąć do części podziemnej kopalni. Co więcej, wartości 3H w ściekach odprowadzanych z podziemnej części kopalni sugerowały, że wiek wód podziemnych wynosił nie więcej niż około 60 lat.

4

Forecast of methane emission from closed underground coal mines exploited by longwall mining - a case study of Anna coal mine

Duda A., Krzemień A.

Journal of Sustainable Mining

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2018

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Vol. 17, iss. 4

184--194

EN

Closure and post-closure periods in underground coal mines present specific risks that have to be handled with sound management practices in order to achieve sustainability within the mining sector. These risks may negatively affect the environment and result in hazards on the surface caused by phenomena occurring in the rock mass after mining operations. One of the hazards that has to be considered in the process of coal mine closure is gas, which is caused by methane emission after mining operations cease. This paper presents a forecast of methane emissions conducted within the framework of the Research Fund for Coal and Steel “MERIDA” project, using a model that was developed by the National Institute for the Environment and Industrial Hazards (INERIS) from France, and the Central Mining Institute (GIG) in Katowice, from Poland. This model enables the estimation of the volume of methane emitted into longwall goafs from relaxed undermined and overmined coal seams in order to assess in a further step the risk of methane emissions into the atmosphere from closed/sealed underground coal mines. For a critical analysis of the forecasted methane emissions into the longwall goafs, the results obtained with this model were compared with a gas decline curve generated for longwall goafs from closed/sealed underground coal mines in Australia, where long term full range data was available. The results of the analysis allowed the forecasted emissions and, thus, the accuracy of the model to be validated. The forecast was developed in the “Anna” coal mine, property of the PGG Company, which is located in the southern part of the Upper Silesian region in the south of Poland, near the border with the Czech Republic, and that is undergoing a closure process.

5

Geochemical analyses of ground air within the hole exploitation of Hard Coal Mine KWK Morcinek

Macuda J., Zawisza L.

Gospodarka Surowcami Mineralnymi

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2008

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T. 24, z. 3/1

343-351

EN

Closing of hard coal mines leads to quantitative and qualitative changes of a number of environmental factors. Water and ground are one of the most endangered environments under the negative impacts of mines' closing operations. Among the most important hazards are methane and carbon dioxide emissions from the coal beds. Intensification of gas flow to the surface area is most frequently caused partial or entire stopping of mine's waters pumping. This results in reconstruction of the Carboniferous aquifer, and consequently, the so-called 'piston effect'. In the closed mined this effect may be considerably intensified after stopping ventilation of the abandoned workings. The results of geochemical analyses within a closed Coal Mine KWK Morcinek are presented in the paper. The investigations were aimed at evaluation of the scale of occurrence of mine's gases in the surface zone and principles of its detailed geochemical monitoring.

PL

Zamknięcie kopalni węgla kamiennego prowadzi do powstania ilościowych i jakościowych zmian pewnej liczby czynników środowiskowych. Woda i grunt należą do środowisk najbardziej zagrożonych przez negatywny wpływ operacji zamknięcia kopalni. Do najważniejszych zagrożeń należą emisje metanu i dwutlenku węgla ze złóż węglowych. Intensyfikacja przepływu gazu na powierzchnię terenu najczęściej wynika z częściowego lub całkowitego zatrzymania pompowania wód w kopalni. Powoduje to zmiany struktury karbonowych formacji wodonośnych, a w efekcie tak zwany 'efekt tłokowy'. W zamkniętych kopalniach efekt ten może być znacznie bardziej nasilony po zatrzymaniu wentylacji w starych wyrobiskach. W opracowaniu podano wyniki analizy geochemicznej w zamkniętej kopalni węgla KWK Morcinek. Badanie miało na celu ocenę skali występowania gazów kopalnianych w strefie powierzchniowej oraz szczegółowe zasady monitorowania geochemicznego.

6

Development of a mineral deposit as a sustainable economic unit

Sinha S. K., Singh A. K.

Gospodarka Surowcami Mineralnymi

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2008

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T. 24, z. 3/1

465-470

EN

Closure of a mine is more certain than starting it. Kamaishi mine of Japan is an example of the development of a mineral deposit as a sustainable economic unit, where revenue earned today is comparable, when the mine was operational. Alternative possible measures to be taken during active mining life have been suggested like Afforestation, Water Harvesting, Tourism etc. to earn the desired revenue during post mining period in the article.

PL

Zamknięcie kopalni jest bardziej pewne niż jej uruchomienie. Kopalnia Kamaishi w Japonii jest przykładem opracowania złoża mineralnego jako jednostki zrównoważonej ekonomicznie, gdzie dochody zarabiane obecnie są porównywalne z tymi z czasu, gdy kopalnia pracowała. Zaproponowano alternatywne środki do podjęcia w czasie aktywności kopalni, takie jak zalesianie, hodowle wodne, turystyka, itp., których celem jest wypracowanie żądanych dochodów w okresie po zakończeniu eksploatacji.