Stripping lasted until 1982. A year later, mining of the deposit began. Since 1983 to date, around 194.6 million tonnes of ore with an average copper content of 0.342% have been excavated totalling to about 665,000 tons of copper ore. In order to obtain copper, it was necessary to mine around 178.8 million tonnes of waste (waste coefficient of 0.92).
The remaining verified geological ore reserves amount to over 617 million tons of ore with the average copper content of 0.32%, while the balance reserves amount to 474.3 million tons, with an average content of 0.323%. In total, therefore, the “Veliki Krivelj” deposit with 1,533,821 tons of copper in the ore and an intended increased capacity of up to 10.6 million tonnes of ore per year, is the potential for mining in the next 45 years.
Mine is of a conventional type and mass exploitation is done with the high capacity equipment. Drills of 250 to 310 mm are used for drilling, and for loading the mined ore and overburden excavators of large capacity with a bucket of 15 m3 and 22 m3 capacity are used. Transport to the crushing plant of the ore and waste rock is done by 220 ton trucks.
In the period 2007-2010 the following mining equipment was purchased: five 220 t trucks, five 150 t trucks, one 22 m3 excavator, one 15 m3 excavator, three bulldozers, one drilling rig and one grader. From June 2011 the remaining contractual machinery will be delivered including five 220 t trucks, one 150 t truck, a 22 m3 excavator, one 15 m3 excavator and two drilling rigs.
In the late 2010 the conveyer belt for extended by constructing additional 45 meters for the direct disposal of the waste from the “Veliki Krivelj” mine to the excavated space of the old open pit of Bor.
In the next 10-15 years mining capacity will reach 10.6 million tonnes of ore per year, with an average copper content of 0.28% to 0.38%. Over the next five years, about 20 million tons of overburden will be removed annually, after which the stripping coefficient will be more favourable.
In order to prepare the „Veliki Krivelj” open pit for excavation of 30.5 million tons per year, along with the purchase of new mining equipment, a new development phase will be under way with the investment cycle for the existing deposit.
- Nebojša Videnović – Manager