Extrication of a bucket wheel excavator under the auspices of UNEX

Most February 4 2014 – The inquiry into the emergency incident of the KU 300 bucket wheel excavator in the ČSA quarry is coming to an end. The mining company Severní energetická, on the basis of expert opinions and the conclusions of the emergency committee have established work procedures for the extrication of the bucket wheel excavator. Those will be carried out by the engineering-metallurgical company UNEX from Uničov. The District Mining Office in Most will both inspect the secured operational documentation during the investigation of the reported emergency incident as well as perform head supervision of the extrication of the bucket wheel excavator. The liquidation work will start early next week.

"In Uničov in the second half of the last century more than 120 different types of bucket wheel excavators were produced including the largest machines, capable of independent movement, that man has ever produced. Roughly four dozen of these machines are still in operation, some of them directly in the ČSA quarry. On account of the fact that we are the only legitimate holder of the documentation of the bucket wheel excavators, we still carry out general repairs and reconstruction of these bucket wheel excavators, and because we have an assembly team that has many years of experience with these excavators, we consider it as natural that Severní energetická has chosen us for such a large operation, "said Jiří Mašek, vice president of engineering at UNEX a.s.

"During the extrication of bucket wheel excavator we have mainly two things in mind: the priorities are the safety of people and the need to minimize the damage, or not to allow further damage to be caused to the excavator in such a demanding operation "says Oldřich Vojtek, installation specialist at UNEX a.s. "The exact technique of extrication is determined after ascertaining the actual state of the machine, incl. the functionality of the individual devices. For example we would like to use the hydraulic system of the bucket wheel excavator, at least for its partial lifting. Cranes and various counterweight systems, anchors, supports and the like will certainly come into play as well. We will also draw on the experience of a similar incident that occurred in the ČSA quarry in 1990. Part of the team that worked on the extrication and repair of the bucke wheel excavator back then are still available to us today as well ".

The investigation of the incident has so far shown that difficult geological conditions at the site and the instability of the old mining tunnel are probably responsible for the accident.

"Although we pay the utmost attention to operational safety, and our policies are really the most stringent, similar events may occur. It belongs to the risks of the mining profession, which, although we try to reduce them to a minimum, cannot be 100% eliminated ", explains the managing director of Severní energetické a.s., Ing. Petr Kolman.

His words are confirmed by the fact that the company has received awards for safety in the mining industry several times in the past from the Czech Mining Authority and is again a candidate for the award based on last year's results.