Serbia mining: Rough start at the largest pit of copper mine Bor

9. February 2016. / Mining


In real winter, between planned objectives and lack of spare parts, miners from Krivelj will manage to deliver the projected 860.000 tons of ore with 2.100 tons of copper while trying to compensate for the set back in stripping, according to Milan Delić the manager of the pit.

-We have to be diligent and modest, and find the right ratio between restrictions and production needs in order to get the maximum – Delić says. –The machines are having malfunctions but thanks to a good fleet of additional machinery there were no accidents or  injuries.

Krivelj pit – The plan for January this year at Krivelj pit was similar to last year’s monthly plans. It was 860.000 tons of ore and 2.1 million tons of overburden. The projected content of metal was 0.256 percent so that delivery of the above mentioned quantity of ore would result in 2.137 tons of copper. According to Milan Delić, the holidays and winetr weather impacted the work of miners so the results are somewhat worse than for the same period in December. Still, they can be considered solid if we have in mind that there were set backs in the floatation and transport system. In 21 days they delivered 550.130 tons of ore with 1.370 tons of copper and if there are no more ste backs by the end of the month it is realistic to expect them to reach the projected quantities. Unfortunately the same cannot be said for overburden, there was a huge set back.

-We did not do good with the overburden due to the overhaul of the transport system – Delić said – But we hope that if there will be an adequate delivery of system parts for the grinder and the trucks in the next few months we will significantly improve our results. People are aware of the graveness of the situation, the restrictions and the responsibility for the large job they are doing on expensive machinery. I think that those people that handle the machines as well as those maintaining them are trying hard to conduct restriction measures. And we have to save every penny – for the explosives, oils, dumper tracks even bolts and electrodes… Because of the large drop in the price of copper it is the only formula for the preservation of the company and reaching more stabile ground. We have to be diligent and modest, and find the right ratio between restrictions and production needs in order to get the maximum.

It is good that after a while the transport system with replaced chains started operating as well as the first overhauled grinder for the overburden. By January 18, all the overburden was driven away from the mountain, and since the roads were covered in snow the results had to be worse – In the next few monts we will organize production so that the biggest part of the overburden will be transported by the transport system. With reducing the lenght of the road the trucks need to pass it will reduce the consumption of gas, and with increasing the tempo of stripping we will have the continuity of ore delivery. The temperatures at the pit dropped to minus 20 degrees, so we had malfunctions, but there were no accidents or truck accidents. Because all the time we had a good fleet of mechanization: two grinders, two dredges and one power shovel. We used them to maintain the large transport network of the pit including the road to Cerova and bypass for the delivery of fuel, so we passed that test too.

Low temperatures redirected the attention of the miners to the sector of deflooding the pit, since there is a significant inflow of water both from Kriveljska river which flows alog the line of the pit and the melting snow. In order to avoid icing, the handlers of pumps changed shifts at the very spot since evrything would freeze if the pumps stopped for an hour or two and it would take a couple of days the put the system back in order.

Last year 25.615 tons of copper in the ore

The second half of last year, is the best example that they are capable of opearting well if there are no major set backs. The plan for 2015 was 10.53 million tons of ore, while 9.41 was dug out which is 89 percent. However due to a better content of metal instead of the planned 25.174 tons of copper in the ore there was 25.615 tons or a percent and a half more. As for the overburden, the plan was optimistic and the beginning of the year was weak like this year (also due to the number of available trucks, decreased operating of the transport system, frequent problems with the conveyer at the edge of the old Bor pit), It was not until July that they noted the increase in stripped quantities (to 1.3 million tons). In August they dug out a record 1.708 million tons of overburden (almost 85 percent of the plan), in September 1.528 million tons and in October 1.475 million tons. The November balance was 1.376 and in December 1.300 million tons, transmits

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