Today, during the global energy crisis caused by the war in Ukraine and the problems with the delivery of Russian gas, coal has regained its importance, even in countries where coal-fired thermal power plants have been shut down.
It is a well-known fact that the energy potential of our country depends on the exploitation and combustion of low-calorie coal that is mined in Kolubara and Kostolac, and that we get over 70% of electricity from our thermal capacities. In recent years, there has been a major campaign against coal as an energy source in favour of renewable energy sources. Such a campaign originates in the European Union, and the goal is to completely replace coal with other environmentally friendly sources. Numerous prerequisites have been put in front of Serbia, which is on the path to the EU accession. The fact is, however, that we do not have a suitable alternative in renewable sources, or not to an adequate extent that we can completely give up coal. The situation is such that Serbia’s energy stability will depend on the exploitation of our lignite for a long time to come, which of course does not mean that the share of renewable sources should not increase year on year. Special emphasis should be placed on the fact that today, during the global energy crisis caused by the war in Ukraine and the problems with the delivery of Russian gas, coal has regained its importance, even in countries where coal-fired thermal power plants have been shut down.
As a mining engineer, I will write about the raw material base and the problems in the exploitation of coal, on which the efficiency of the thermal energy capacities in Serbia depends. What is the quality of coal that is mined in surface mines in Serbia and what can we expect in the long run? All our surface mines in the Kolubara and Kostolac basins share the same predicament – the quality of coal is declining, but other parameters also vary, such as the increasing share of tailings, combustible sulfur content, ash content, etc. For example, in the case of the Tamnava Zapadno Polje surface mine, it’s been projected that the average coal quality has a declining trend, so at the end of exploitation, the average ash content over 18.5% and calorific value (LCV-lower heating value) around and below 7 GJ/t are expected. The same applies to coal from PK Radljevo, where the average ash content is expected to increase to over 17.7% and the LCV to fall below 7 GJ/t in coal. All these facts inevitably impose the need for coal treatment before combustion in thermal power plants.
In the distant future, the exploitation of oil shale should also be considered, which can be a significant resource for the production of electricity and oil.
In addition to intervening in the technology of surface exploitation, in terms of selective excavation, the application of coal homogenization is also required. Furthermore, there is a growing need for coal purification to improve the quality of coal delivered to thermal power plants. One of the important questions to consider is whether the quantities of coal that we are currently exploiting are sufficient to supply our thermal power plants, especially when we take into account that the construction of the Kostolac B3 Thermal Power Plant with a capacity of 350 MW is underway. All these thermal energy capacities are planned based on lignite exploitation in the two aforementioned coal basins. Unfortunately, we are already facing insufficient quantities of quality coal, and even import is being considered.
As for the alternative to the existing surface exploitation of lignite from the Kolubara and Kostolac coal basins, significant exploitation reserves of lignite have been determined in the Kovin basin, close to 200 million tonnes, so this deposit will probably be interesting to consider in the future. As far as underground coal mining is concerned, brown coal is interesting from the aspect of thermal energy raw materials, so the Soko and Štavalj deposits can be appealing given the significant reserves, but significant investments have to be made in the modernization of mines in this area in order to achieve the required capacity increase.
In the distant future, the exploitation of oil shale should also be considered, which can be a significant resource for the production of electricity and crude oil. It has been estimated that the Aleksinac basin alone has geological reserves of about two billion tonnes, while there is a total of 4.5 billion tonnes of oil shale all over Serbia.
SUSTAINABLE MINING AND ENVIRONMENTAL PROTECTION – A POSITIVE EXAMPLE
As an economic branch, mining has recently been criticized by various environmental and other movements and associations, now more than ever, and mining is generally marked as a major threat to the pollution of all environmental media. The question is what is our reality, but also what needs to be done for mining to become environmentally friendly, i.e. sustainable.
Speaking of sustainable mining, whatever that means, we must reconcile the two sides – one is the real need as a prerequisite for modern living and that is the exploitation of minerals and the other is the increasingly developed awareness that we must preserve the environment for future generations. There is a lot to say about this and not everyone will ever agree or share a common view. As a mining engineer, I will always advocate and support the development of mining through new research and potential exploitation of mineral resources. I would not like to go into that in more detail, but I must underline that the state must play a greater role in the profit made by the exploitation of mineral resources and that this should be one of the key prerequisites when launching a new project. This is something that has to be known in advance, namely what financial effects and other benefits are expected, through the collection of all types of taxes, contributions, ore rents and paying out salaries, as well as through the participation of our companies in projects. Special attention should be paid to the best interests of local communities where the mines are located, as their support is very much needed. This is why the sustainability of the project is of great importance, in terms of environmentally acceptable negative impact on the environment.
To achieve that, the latest exploitation technologies, processing of useful substances and safe disposal of mine tailings and mining waste must be applied. The protection of groundwater and waterways, the rational consumption of water resources, the protection of land and, of course, air quality all must be taken into account. Is that possible in practice? I think it is. Although we have a lot of bad examples around us, and there are probably more than we are not even aware of, I would like to cite an encouraging example from our recent practice. After several decades, today we have the opportunity to attend the opening of the copper and gold mine, which is incredibly important for this part of the world.
I am happy to report that the Mining Institute also had its role in that because we inspected the mine’s technical compliance during all three phases of the opening and exploitation of the Čukaru Peki deposit, that is the upper zone, down to 260m underground. This mine fulfilled all its legal obligations regarding environmental protection, and in some segments, it even went up and beyond. I will not go into the project details because it would take up too much time, but I will mention several good solutions such as the technology of filling the excavated pit space with paste backfill, where part of the tailings is returned to the excavated space, whereby the possibility of deformation and subsidence of the terrain on the surface is significantly reduced.
This year, the 8th Balkan Congress will finally be held in Belgrade, organized by the Mining Institute, from September 28 to 30. The Congress was initially postponed due to the coronavirus pandemic.
Also, the treatment of wastewater is environmentally friendly, because wastewater is not discharged into waterways but is treated, purified into the water and returned to the technological cycle of preparation of mineral raw materials primarily. After purification, the residue in the form of neutralized sludge is pumped to the specially designated landfill or flotation tailings. All these facilities are built in line with the highest environmental standards, i.e. they are protected with a waterproof foil so that pollution of the surrounding soil and groundwater is prevented. In terms of treating purified water, I am primarily referring to the treatment of water taken from pyrite concentrate landfills, tailings landfills and drainage water from pyrite concentrate landfills (process wastewater) and the treatment of water extracted from underground mining facilities (mine wastewater).
Of course, these are just some of the solutions that demonstrate the seriousness and determination in reducing the negative impacts to an acceptable level. I would also like to point out here, and this is strongly related to the sustainability of mining exploitation, is monitoring the impact and adequate reaction, through constant monitoring, but also regular inspections and mining and environmental inspections, so that the mine is operational at all times while adhering to all project measures. This is very important because we are witnessing that, in practice, disturbances during mining exploitation are often ignored, which can significantly jeopardize the quality of all environmental media.
Last but not least, I would like to point out that mining has no alternative, that the exploitation of mineral resources can contribute to the economic progress of the country, but also that all possible negative impacts on the environment should be seriously understood and considered, and that through the use of new technologies we can minimize these negative impacts. This is the true meaning of sustainable mining if we can call it that.
ACTIVITIES OF THE MINING INSTITUTE IN SERBIA’S MINING SECTOR
The Mining Institute carries out its activities in line with market principles. The Institute has been utilizing its potential during its decades-long work (founded in 1960), depending on the needs of the mining economy. In addition to the Design Bureaus, the Institute has also developed its own accredited testing laboratories such as the Geomechanics Laboratory, the Environmental and Working Environment Protection Laboratory and the Solid Fuels Laboratory. These are several important projects and services that the Institute is currently working on – with the help of conceptual and construction projects, it provides solutions to the problem of external transport, including ash, slag and gypsum landfills for the Chinese company CMEK in the construction of Kostolac B3 Thermal Power Plant, carries out inspections of technical compliance of mining facilities at the Čukaru Peki Mine, is engaged in the Belgrade Subway project, conducts testing and calibration of automatic measuring systems in Serbian thermal power plants, measures emissions of pollutants, carries out coal quality testing, etc.
This year, the 8th Balkan Congress will finally be held in Belgrade, organized by the Mining Institute, from September 28 to 30. The Congress was initially postponed due to the coronavirus pandemic.
I would also like to mention the publishing activity of the Mining Institute. In addition to the magazine Rudarski Glasnik (The Mining Gazette), which is published regularly, the Institute has recently published a very important monograph, written by a group of authors, and called ‘The Mineral Resources Complex of Kosovo and Metohija’.