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OPERATIONS OVERVIEW
MINING Access and Haulage
The mine is access by a 5.5m diameter concrete lined circular steel shaft (Kapitalna Shaft) which is 345m deep (Collar elevation is at 731m ASL). The operations access is on the 405m ASL elevation which handles wagon haulage and hoisting, and also men and materials on rail track. The shaft bottom is 28m below the 405m level.
Hoisting from the Kapitalna Shaft rated at up to 3000 tons per day is via a double deck twin cage system which hoists two 4.2 tons capacity rail wagons per lift to a semi-automated mechanical wagon exchange and weighing arrangement in the headframe which direct feeds ore into primary crushers.
In addition, there is possible hoisting capacity of up to 1000 tons per day from the Zapad Shaft, which is a 3.3m diameter concrete lined skip/counterweight shaft connecting the 405m ASL rail haulage elevation which is normally used to hoist waste.
The mining operation is accessed via two trackless haulage ramps to the eastern and western zones, accessing the orebodies. The truck haulage (using 40 and 50 tonne capacity trucks) ramps connect at the 450m ASL elevation where a double ore pass truck tipping arrangement feeds rock passes down to the 405m ASL rail haulage level. Chutes then load ore or waste into the 4.2 tons capacity rail wagons for haulage to Kapitalna or Zapad shafts.
During 2004, a new decline from surface was commenced, which will link the mine surface with the 450m ASL elevation, and facilitate the movement of men and materials, along with the instant ability to raise to surface higher tonnages of ore than is possible with the existing shaft capacities. Ore Production
The mining method used at Chelopech was sub-level caving (SLC). Sub-level intervals, at 15m vertical distance, were developed with interconnecting longitudinal drifts and drawpoint crosscuts set at 12m centres using electro-hydraulic two boom drill jumbos, and mucked using loaders with between 10 and 17 tons bucket capacities.
Production drilling for blasting with ammonium nitrate/fuel oil (ANFO) is carried out using automated, electro hydraulic drill rigs.
Control of the SLC is critical in order to minimise dilution. Grade control geologists monitor all production mucking from the SLC drawpoints on a continuous shift basis. 
Sub Level Caving
Studies of the geotechnical characteristics of the geological setting have shown that longhole stoping with subsequent fill can be undertaken at Chelopech. Longhole stoping has the potential to extract reserves at low ore losses and provide the high production rates required by the Chelopech operation. In conjunction with longhole stoping, cemented fill made from process tailings will be introduced to ensure stability and allow the mining of adjacent stopes. The other advantage of this mining method is that it allows the operation to arrest further caving to surface – an effect of sub-level caving methods, and thereby stabilising the environment.
The introduction of longhole stoping with fill will allow the operation to increase production to its current target of 1.5 million tons per annum.
The same equipment that is currently used in the operations will be used for open stoping, with the introduction of additional 50 ton capacity trucks, and 17 ton bucket capacity loaders. 
Open Stopping Mine Infrastructure
The two hoisting shafts, Kapitalna and Zapad shafts are air intake airways. Additional circular shafts (Sever and Iztok, 4.0m and 3.1m concrete lined respectively) are exhaust airways.
Chelopech is not a wet mine, and the use of industrial water for drilling, dust suppression etc. is the main contributor to the annual pumping requirements.
Diesel for underground equipment is supplied by a direct supply pipeline from surface to a new refuelling bay close to the centrally located 450 level tip facility.
All main production and development drilling is carried out by conventional electro hydraulic drilling. Underground 30m3/min compressors, permanently located at strategic points, supply the mine compressed air requirements.
Electrical power is provided by a secure ring main from the National Grid at 110kV through two 16 MVA 110/6kV transformers. Distribution into the mine at 6kV is through four parallel feeders with modern protection systems. On each production level transformers supply 380V and 1000V power for the production equipment (the mine is in the process of converting to 1000V distribution).
A steel lined borehole from surface to the 450 level transports high quality road ballast from surface directly underground to the ramp system.
Additional boreholes are currently being installed for the introduction of cemented paste tailings as fill for the new longhole stopes after excavation. A surface batching and mixing facility for the introduction of cemented tailings underground is under construction. |
