Preparations for the third relocation of a part of the Kolubara river bed26. July 2013. / Mining
Temporary works on the river flow changing are in ful swing,as the project documentation is being completed.
At the end of May,the experts from the Jaroslav Cerni Institute of Belgrade finished the Main Design for the second phase of the project forKolubara riverbed relocation including the Peštan tributary and the Main Designfor the water supply system for the branch “Prerada” (Processing plant) and submitted them to the departments of MB “Kolubara”. The revision of these two major documents being entrusted to the Faculty of Civil Engeneering of Belgrade is expected to be finished these days. The completionof project documentation is very significant for the third relocation of the Kolubara river as one of the biggest construction undertakings dealing with the relocationof big infrastructure structures. These works are part of the so calledpreparations for the opening of the new OPM “Field G”. Regarding the progress of the works on relocation of a part of Kolubara riverbed and what remains to be done, Mr. Goran Marković, the head of Supervision Department, says:
– “Kolubara” in the meantimehave started many operations that will shorten the time of some obligations. We harmonized the amendments of the Main Design by the accelerated procedure as it is currently being revised. It required from us to be constantly in touch with the designers and reviewers and to solve all the issues on the go without waiting for them to send us in writing their comments and amendments. According to this fact the time necessary for the revision will be shorten by 10 to 15 daysfrom the usual and about the same time will be saved on the printing of the documents. In this way, the conditions are acquired to begin preparations for the procedure of announcement an international tender for selection of the most favorable contractor.
The Main Design for the relocation of the Kolubara riverbed in the length of 2.6 km consists of two parts. The first part is about the relocation of the rivers Kolubara and Peštan includingthe bridges,while the second partcontainsan additional mining project which includes the construction of a pumping station as a part of a water supply system for the “Processing Plant”, construction of a pipeline and construction of a bypass road around the Field “G”, about 3 km long, that will also connect villages Skobalj and Vreoci.
Preparatory earthworks for the relocation of Kolubarariverbed started on 5th July last year on the so called native ground and exactly at the junction with the dumpsite. It was necessary in order to monitor theterrain subsidence parametersfor a longer period,because that unconsolidated deposited massis actuallythe most sensitive point of this project.
We worked in this section of the native ground by November last year and then we moved to a similar terrain above the cascade. The first section of about 500 m was finished by October, and the second one 700 long is planned to be finished by the end of July this year. From that point on, we planned to start intensive excavations in the dumpsite area of the corridor. We are supposed to excavate about 250,000 m3 of disposed soil. If everything goes as planned,by May next yearwe expect that all the excavation will be completed and onlythe bridging will remain to be done.The last section of the new riverbed must be worked on together with the Contractor – explains Mr. Goran Marković, adding that the experts of “Kolubara” have already solved many issues and dillemas during these operations, and that they have responded to all the challenges. For example, in this phase, the so called “clay cap” was made of the best clayey materials, as a difference from what was done in the first phase.The operations were carried out very carefully to avoid possibility of the geomembran cracking under the pressure ofthe mass from the upper side, which would subsequently result in water leakage..
The Kolubara riverbed relocation is lead by the expert team of “Kolubara”, and workersfrom the overburden system “Tamnava –East” are involved with three draglines “EŠ“ and complete mechanical and electrical support. Those workers are really experienced and they were also engaged during the first phase of the riverbed relocation. Our interlocutor stresses that it is important to realize that the structure has been built for the needs of mining. Basically, we have here an excavation for a high dam, which is something that requires high precision and caution. The worksarecarried out in three shifts. There are also difficulties caused by the lack of the auxiliarry machinery.
Be as it may, the sight of the new riverbead looming in the field is quite encouring.
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