Mass Mining using Room and Pillar Methods at Estonia Oil Shale Mine

摘要

The Estonia Mine, operated by Eesti Energia Kaevandused AS (EEK), the mining division of thernEstonian Government’s energy company, Eesti Energia AS, is a large room and pillar mine located inrnEastern Estonia. It supplied approximately 4.9 Mt/a of oil shale in fi nancial year ending 2010, whichrnis used for electricity and shale oil generation. Due to the Estonian climate and the power station’srnneed for a dry product, Estonia Mine has developed a planning system where short-term demandsrnof the power stations dictate the schedule. Such an arrangement requires maximising fl exibility andrnconsequently the mine only operated for 199 days in 2010.rnThe footprint plays a key role in achieving mass mining rates as the 12 km × 12 km lease area allowsrnthe mine to split into mining districts that act independently of each other and maximise the numberrnof work areas available. Coupled with this, the geology of the mine is relatively homogenous over thernmining lease, simplifying the mine design and production methods.rnDuring the last five years, EEK has commissioned a comprehensive conveyor network.rnConsequently, material handling only requires loaders to dump oil shale direct from thernproduction face onto a chain conveyor that feeds the conveyor network that ultimately suppliesrnthe enrichment plant. Dewatering is also of critical importance, with 90 Mm3 of water dischargedrnannually. EEK uses large trenches up to 3.5 m deep and 1.2 m wide to channel groundwater.rnTrack mounted mechanical saws are used to cut slots in the floor, to control overbreak in blastingrnthese trenches.rnEEK has introduced Salzgitter Machinenbau GB 280S auger drills that drill three 280 mm diameterrnholes simultaneously. This has improved void hole drilling times and reduced the drilling requiredrnfor each face, reducing the overall production cycle time. Blasting activities have also been decoupledrnfrom other mining activities negating the need for fi ring times through the use of small independentrnfi rings, required to control vibrations.