Serbia energy security report after floods: Serbia battling for Kolubara mines coal supply to TPPs

9. June 2014. / News Serbia Energy

The good news is that Thermal power plants TENT Nikola Tesla “A” is put in operation, and the bad one is that the most productive Kolubara lignite open pit mines have been flooded. The only consolation is that previously shut down mines have been activated and that a fifth of sometime production will be managed to be excavated and that with transitional reserves will provide as much national electricity as possible for the following month or two, and the disturbing news is that getting back “to previous state” will last for a year. How fast will Serbia power utility EPS manage to overcome coal supply and avoid big electricity imports is a million dollar question not only for Serbian government but also for electricity traders.

It is not still known how much water has flown down the Kolubara river those couple of days at that point: according to some unofficial estimates, emphasizing “unofficial” and “estimates”, meaning that this should be taken with caution, the flow reached (almost) 1200 cubic meters per second, and if embankment had not collapsed, if that tremendous amount of water had not rushed into the open pit mine, those 210 million cubic meters of water would have ended up in Obrenovac where the level of water would have been on average two to three meters higher. And those rumors about hundreds/thousands of drowned people would not be spreading false news, but far exact information, leaving aside the fact the Thermal power plant A, and possibly TPP B would have been flooded, and thus material damage would be beyond compare.

This way, two coal mines have been completely flooded: “Tamnava – West Field” – the most productive Kolubara OPM and “Veliki Crljeni” – the youngest mine. In the first OPM – “Tamnava”, a lake has been formed of around/over 15 square kilometers, of average depth of 14 meters, at deepest points 50 and more meters deep, but in most places five and ten meters. “Crljeni” lake is significantly smaller – it is not announced what area it occupies. Its volume is 28 million cubic meters of water. The water rushed into other mines, but not even close as in these two mines. Nine large-scale excavators (some bucket wheel excavators, some draglines) and numerous very expensive pieces of mining equipment are now under water.

THE SIZE OF THE DAMAGE

According to Mr. Milorad Grčić, Director of the Mining Basin “Kolubara”, the damage is roughly estimated at “a couple of hundreds of millions of euros”. What the damage really is will be known after detailed analysis is made, when the state of flooded mining equipment has been established. As soon as the water flow has been stopped, the flooded mines were visited by professional divers of Belgrade company Coda, specializing in underwater operations. ”Under these circumstances, when just a couple of days passed after dramatic events, we can examine whether there exists a minimum of conditions necessary for carrying out underwater activities. Specialized equipment that we have for panoramic and systematic recording of the situation under water can provide more than just clear situation of the state of the equipment and submerged area – but, in order to prevent any harm to the divers, it is required for the underwater visibility to be at least a hundred centimeters”, they explained adding that they participated in evacuation of Obrenovac, and that the taking shots in “Kolubara” depending on the job scope, could be done free of charge.

According to the Director of “Kolubara”, pumping out and recovery of the Crljeni mine, again roughly speaking, will take at least two months, and for the Tamnava mine up to a year and a half.

Only a day before the Peštan and Kolubara river were about to flood the mines, and when Valjevo was already flooded, the Operative emergency team of MB Kolubara made a public announcement saying that “currently none of the four active mines was at risk of floods, and that coal production was being carried out with no major problems, though under difficult conditions”, that 24-hour duty was introduced in all mines, and that it had been agreed “to monitor watercourses of the Peštan and Kolubara river, surrounding the open pit mines”.

Kolubara, Peštan and Turija River overflowed their banks that same night. The next day, in an official statement it was announced that the overflowing of the rivers affected the population, that the water went directly towards the pits “Veliki Crljeni” and “Tamnava West Field”, that the mines could not be approached, thus the production process was halted and would not be continued until the weather conditions were stabilized. Please note: all previously described were happening a day before a sound alarm in Obrenovac was alerted, albeit painfully too late.

Five days later, the Operational Team for the Emergency of MB “Kolubara” informed the public that “after more than two days of uninterruptable superhuman efforts the embankment was built on the river Kolubara and the outflow of the water stream into the Tamnava’s open pit mines was stopped.

In the special edition of the “Newsletter” of this public enterprise, the details have been announced: in just a few hours, Kolubara River has made a gorge of 50m width and 30m depth, the roar of the water could be heard at the distance of five kilometers, in the repair of the embankment the 10,000 cubic meters of soil and stone of coarse granulation were built, two large pumping stations were installed which would first pump out the water from the open pit “Veliki Crljeni”, then from the “West Field”, which has much more water than the first-mentioned.

ONCE UPON A TIME…

Mining Basin, named after Kolubara River, is divided into two parts – East and West. The East part is surrounded by the rivers Turija, Peštan and Kolubara, and the West part is between Kolubara, Tamnava and Ub. At the beginning of this century, the Institute “Jaroslav Černi” made the General Design of relocation of Kolubara’s riverbed, which was the prerequisite for the further development of the long-term coal mining in the central part of the lignite basin in the next 20 to 40 years.

In the “game” were two versions – “East” and “West”, each with numerous subversions. According to the Eastern variant, the capital line system – river Kolubara, Belgrade-Bar railway and Ibar highway, should be grouped into a single corridor, while the Western suggested the relocation of the river on the inner dumpsite, or used mining field. The second one – the Western – has been accepted.

The explanation of the project states that this procedure should ensure the protection of the coastal resources – mining and industrial facilities, roads and agricultural land from the flood water of Kolubara River on the mentioned route. Technical Inspection report was conducted in October 2008, achieving the condition for opening of the, now flooded open pit mine “Veliki Crljeni” and exploitation of almost 29 million tons of coal.

The degree of protection for the left and right bank of the new riverbed of Kolubara River is projected for “one hundred years of great waters” – a flow of 705 cubic meters of water per second, with the reserve overshoot to a level of “one thousand years of great waters” estimated at 940 “cubics” per second.

WATER FLOW

Generally, the average flow of the Kolubara river is 31 cubic meters of water per second, although in some studies it is indicated that the flow is (only) 25 cubic meters per second. However, the Kolubara river with its tributaries is one of the rivers with a rain-snow regime: when it rains and/or when the snow melts, the river swells, when there is no rain, the river is still. Sudden and large variations of water level and flow are important characteristics of its water regime, which is a significant difficulty for the water supply of settlements and industry, protection from torrents, flooding and erosion. Therefore, there is a big difference between the average amount of water and centennial, i.e. millennial “big water.” The dam Stubo-Rovne was built due to these characteristics of the Kolubara. It could have had a key role during this flood, but it hasn’t had it because The Serbian Orthodox Church, in every way, has been successfully blocking by now its putting in operation, because the dam allegedly threatens the church of Arhandjel Mihajlo – the Gračanica of Valjevo.

REALLY A LOT

The amount of water in flooded open pit mines has been estimated to 210 million cubic meters, which is a volume of 42,000 Olympic pools, three and a half accumulations of Stubo-Rovne and nearly “ two Vlasina Lakes“, as it was estimated by the Prime Minister Vučić at the Coordination Meeting of the international donors, it is (only) a quarter larger .

However, it is a huge amount of water: Drina would deliver this amount, at medium flow, for 146 hours to the confluence of the Sava river, the Sava to the confluence of the Danube for 34 hours, and the Danube, at medium flow near Belgrade for 10 hours. According to the announcement of the Emergency response team of MB “Kolubara”, the water rushed in during the night between Wednesday and Thursday and the embankment was definitely rebuilt during the night between Sunday and Monday. For how many hours exactly the Kolubara river was flooding the open pit mines isn’t known, nor do we know anything about the dynamics, but the amount wasn’t the same on the first and last day/hour.

If we assume that all five days, i.e. for 120 hours, water was rushing uniformly, as it did not, the average flow would be 486 cubic meters of water per second, which is equivalent to a double middle water flow of the Velika Morava near Ljubičevo bridge, or “Drina and a quarter” at the confluence of the Sava river.

In the special edition of the “Newsletter“ it is said that the open pit mines were already flooded “the following morning”, let’s say 30 hours after the braking of the embankment: in which case, the Sava with a slightly higher flow was flowing into the open pit mines.

All indicated numbers are the result of relatively easy calculation which is based on “average of the average of the average”, and what really happened and which river was flowing in the Kolubara’s bed and for how long, it could be explained only by the professionals/scientists: something has happened which has never been considered as a possibility and in the future it has to be taken into account.

Computer simulation could answer the question “what happened”, but also “what would have happened if it had happened” – what would have happened to Obrenovac if there had been shutters on Stubo-Rovne dam, if “24 hour duty “ hadn’t been organized on the wrong side of the open pit mine, had the embankment super elevation been built for supposed level of “millennial great waters”, envisaged by the project; had the passage been opened for the torrent to the OMPs which were no longer active, on time, if …

WE ARE MOVING ON

Be that as it may, that is all water under the bridge, and now the priority is what’s coming – sanation: pumping the water out of the OPMs and putting the machinery back into operative state. It is not important how much it will cost, since the entire EPS is, allegedly, insured and reinsured, so the damages will probably be paid from that source, to the extent and under the conditions agreed upon by the contract on insurance and reinsurance.
The overhaul of the equipment should not be a problem: Kolubara has qualified human resources – engineers and craftsmen who maintain the equipment every day and who managed to keep the system vital during sanctions, therefore they will be able to do it now. However, the problem is how the OPMs will be pumped out and how long it is going to take: the professionals who work here have never had such a huge challenge. One thing is for sure: the water must flow out using the same path that led her to the OPMs, and that is Kolubara river bed, and for that to happen there is only one possible way – pumping out.

Apart from the helicopters and boats, the “high capacity pumps” were quite often mentioned as a part of saving equipment: At the dramatic and pathetic government/headquarters meeting, while the Prime Minister Vučić was adressing “our friends”, he kept pointing out that along with helicopters and boats, we also need the pumps. The journalists reporting “from the field” paid special attention to the special “high capacity pumps”, brought by the foreign rescue units, which were able to “pump out 5,000 liters of water per minute”. The Minister of Energy was so excited to describe the pump brought by rescue unit from Czech Republic, the capacity of which was 25,000 l/min,

We shouldn’t be surprised by the amazement the figures caused: many zeros in capacity description in very short term really look great. However, if we introduce seconds instead of minutes and cubic meters instead of liters, we get the result with zeros after the decimal mark.

For example, that “journalists’ pump” (5,000 l/min), which pumps out the water from a basement “in the blink of an eye”, would need 1,000 minutes to pump out the Olympic size pool, which is some 17 hours, and the “minister’s pump” would need five times shorter period. However, the capacities of the pumps do not represent a problem: a great number of small pumps combined make huge capacity, of course depending on their number.

Drainage pumps are the parts of compulsory mining equipment, since water can be found anywhere in the soil, and it has an unpleasant tendency to use every passage to go that way, so the water must be pumped out from the mine all the time.

The pumps which amazed the journalists and the minister are, as a matter of fact, the smallest pumps in the category of “mining equipment”: the large ones have the capacity of 150,000 l/min, which is 2.5 cubic meters per second, which means that they could empty the Olympic size pool in less than half an hour.

For pumping out of the “Tamnava lake”, if the estimated volume of 210 million cubic meters and one year for emptying of the lake are taken for granted, we get the average “outflow” of 6.7 cubic meters per second, which, if they are switched on 24/7, (let’s say) 80 “journalists’ pumps”, or 16 “minister’s pumps”, or two and a half “mega mining” pumps could do. So, it is not “the Bible”: nor do we need countless number of them, nor do they cost “100 golden coins”. Some of them we already got through the donations, some of them we have from the previous period.
Let’s not get confused: this calculation, just like the previous one, is based on “the average of the average of the average” and is in no way relevant. And, whether it takes a year or a year and a half for the new “Kolubara lakes” to be pumped out, and what is the actual price of the process, the answer is (again) to be given by the professionals and scientists. However, none of “the kind” has spoken so far.

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