1. Mineral Resources and Mine Development AIMS 2013 Pavlides A. Hristopulos D.T. Galetakis M. Roumpos Ch. GEOSTATISTICAL ANALYSIS OF THE CALORIFIC VALUE AND ENERGY CONTENT OF THE MAVROPIGI MULTI-SEAM LIGNITE DEPOSIT IN NORTHERN GREECE

2. AIMS 2013 PRESENTATION Description of Mavropigi mine Description of Mavropigi mine Lignite energy content and geological lignite Lignite energy content and geological lignite Estimation of Lower Calorific Value (LCV) with a geochemical equation Estimation of Lower Calorific Value (LCV) with a geochemical equation Estimation of LCV with a regression linear model Estimation of LCV with a regression linear model Spatial estimation of the geological lignite energy content Spatial estimation of the geological lignite energy content Conclusions – suggestions for further study Conclusions – suggestions for further study

3. AIMS 2013 MAVROPIGI MINE

4. AIMS 2013 MAVROPIGI MINE Area 11 km 2 with extensive fault system Area 11 km 2 with extensive fault system Multi-Seam mine Multi-Seam mine The mine is in operation since 2002 and has produced 51.8 Μt of lignite till the end of 2012 The mine is in operation since 2002 and has produced 51.8 Μt of lignite till the end of 2012 Average lignite production: 8 Mt/Y Average lignite production: 8 Mt/Y Estimated exploitable lignite reserves: 198 Mt, 146 Mt remaining Estimated exploitable lignite reserves: 198 Mt, 146 Mt remaining Estimated energy content: 350∙10 6 MWh Estimated energy content: 350∙10 6 MWh

5. AIMS 2013 GEOLOGICAL LIGNITE The Criteria used to determine if a layer is considered a geological lignite layer for this study are: LCV greater than 900 kcal/kg LCV greater than 900 kcal/kg Maximum contents in ash and CO 2 up to 55% Maximum contents in ash and CO 2 up to 55% No constraints on layer thickness No constraints on layer thickness The criteria of geological lignite layers differ from the criteria of exploitable lignite layers The criteria of geological lignite layers differ from the criteria of exploitable lignite layers The criteria used are simplified in comparison with the PPC criteria The criteria used are simplified in comparison with the PPC criteria

6. AIMS 2013 LOWER CALORIFIC VALUE AND LIGNITE ENERGY CONTENT Lignite is mainly used as fuel for power stations Lignite is mainly used as fuel for power stations For such use the LCV (heat released/mass burned) is the dominant quality parameter For such use the LCV (heat released/mass burned) is the dominant quality parameter LCV shows intense variability within the deposit LCV shows intense variability within the deposit The LCV variability means that the quantity of the reserves can serve only as an indicator for the amount of contained energy The LCV variability means that the quantity of the reserves can serve only as an indicator for the amount of contained energy the lignite energy content (LEC) of a quantity of lignite is the LCV of the quantity multiplied by the mass of the lignite the lignite energy content (LEC) of a quantity of lignite is the LCV of the quantity multiplied by the mass of the lignite

7. AIMS 2013 ESTIMATION OF LCV To estimate the LEC for all or part of the mine, LCV must be known for the whole area investigated To estimate the LEC for all or part of the mine, LCV must be known for the whole area investigated LCV is not measured for all core samples. Only 4416 core samples have an LCV measurement out of 10208 core samples LCV is not measured for all core samples. Only 4416 core samples have an LCV measurement out of 10208 core samples The LCV for the remaining 5792 samples must be estimated The LCV for the remaining 5792 samples must be estimated The first method is based on a geochemical equation The first method is based on a geochemical equation The second method is based on a regression model that links LCV with measured quality parameters of the core samples The second method is based on a regression model that links LCV with measured quality parameters of the core samples Results are compared with the measured values of LCV Results are compared with the measured values of LCV

8. AIMS 2013 GEOCHEMICAL EQUATION Equation by Rheinbraun Equation by Rheinbraun Parameters of the equation Parameters of the equation Comparison of estimated and measured LCV ccal kcal/kg w%w% α % ca kcal/kg le % cw kcal/kg5800measuredmeasured-43727.5-583 Pearson's ρ Mean error (kcal/kg) Mean abs error (kcal/kg) Mean absolute relative error 0.8657-71.54104.380.085

9. AIMS 2013 MULTIPLE LINEAR REGRESSION It is assumed that the LCV can be estimated from a linear equation It is assumed that the LCV can be estimated from a linear equation Parameters of the equation (kcal/kg) Parameters of the equation (kcal/kg) Comparison of estimated and measured LCV The LCV for the 5792 samples that miss it are estimated using the linear regression model The LCV for the 5792 samples that miss it are estimated using the linear regression model Pearson's ρ Mean error (kcal/kg) Mean abs error (kcal/kg) Mean absolute relative error 0.93320.0061.00.045 α1α1 α2α2 α3α3 α4α4 -4114-2470-27274590

10. AIMS 2013 LEC DENSITY To make easy estimations of the LEC for parts or the whole mine, a map of the estimated LEC per unit of surface area (m 2 ) or LEC density will be created To make easy estimations of the LEC for parts or the whole mine, a map of the estimated LEC per unit of surface area (m 2 ) or LEC density will be created LEC density (Gcal/ m 2 ) is the total energy content that would be gained if all the geological lignite below a unit of surface area is mined LEC density (Gcal/ m 2 ) is the total energy content that would be gained if all the geological lignite below a unit of surface area is mined LEC density changes from part to part of the mine, based on the total lignite thickness and the LCV of the various lignite seams below the investigated unit of surface area LEC density changes from part to part of the mine, based on the total lignite thickness and the LCV of the various lignite seams below the investigated unit of surface area

11. AIMS 2013 DRILL-HOLE DATA Data comprise of the LEC density in 343 drill-holes calculated from the LCV of all the 10208 core samples of the drill-holes and the lignite thickness Data comprise of the LEC density in 343 drill-holes calculated from the LCV of all the 10208 core samples of the drill-holes and the lignite thickness

12. AIMS 2013 DATA STATISTICS Mean (Gcal/m2) Minimum (Gcal/m2) Maximum (Gcal/m2) 40.52.6123.3

13. AIMS 2013SEMIVARIOGRAM Experimental omnidirectional semivariogram fitted with the exponential theoretical model with nugget effect. Distances are normalized and a linear trend has been removed (ρ = 69.7%) Experimental omnidirectional semivariogram fitted with the exponential theoretical model with nugget effect. Distances are normalized and a linear trend has been removed (ρ = 69.7%) c 0 (Gcal/m 2 ) 2 σ 2 (Gcal/m 2 ) 2 ξ 60.2345.00.81

14. AIMS 2013 OK OF LEC DENSITY 28 ∙10 6 MWh

15. AIMS 2013 OK OF LEC DENSITY

16. AIMS 2013 OK OF LEC DENSITY To validate the results, leave-one-out cross-validation was used To validate the results, leave-one-out cross-validation was used LEC density (Gcal/ m 2 ) estimated in a 30m x 30m grid LEC density (Gcal/ m 2 ) estimated in a 30m x 30m grid LEC is greater in parts of the mine that have greater lignite thickness LEC is greater in parts of the mine that have greater lignite thickness Using the estimated LEC density of the OK, the LEC for Mavropigi mine is estimated at 300.4∙10 6 Gcal or 349.1∙10 6 MWh Using the estimated LEC density of the OK, the LEC for Mavropigi mine is estimated at 300.4∙10 6 Gcal or 349.1∙10 6 MWh Pearson's ρ Spearman's r Mean error (Gcal/m 2 ) Mean abs error (Gcal/m 2 ) Max abs error (Gcal/m 2 ) 0.860.87-0.1549.75262.10

17. AIMS 2013 CONCLUSIONS - SUGGESTIONS The energy content of the geological lignite of Mavropigi mine is estimated at 349.1∙10 6 MWh The energy content of the geological lignite of Mavropigi mine is estimated at 349.1∙10 6 MWh The LCV for drill holes that miss such a measurement is estimated from other parameters using Rheinbraun’s geochemical equation and a multiple linear regression model The LCV for drill holes that miss such a measurement is estimated from other parameters using Rheinbraun’s geochemical equation and a multiple linear regression model While both methods give good estimations of the LCV, the linear regression model gives a better estimation While both methods give good estimations of the LCV, the linear regression model gives a better estimation The effect of the depth as an independent parameter was investigated. It was concluded that its effects were already incorporated in the other parameters The effect of the depth as an independent parameter was investigated. It was concluded that its effects were already incorporated in the other parameters

18. AIMS 2013 SUGGESTIONS FOR FURTHER STUDY The estimated LCV along with other lignite parameters could be used to make three-dimensional kriging estimate of the location of waste seams and geological lignite seams. The estimated LCV along with other lignite parameters could be used to make three-dimensional kriging estimate of the location of waste seams and geological lignite seams. The LEC density of three dimensional cells (Gcal/ m 3 ) could be estimated, further assisting in the mid-term planning for individual sectors of the mine The LEC density of three dimensional cells (Gcal/ m 3 ) could be estimated, further assisting in the mid-term planning for individual sectors of the mine

19. AIMS 2013 THANK YOU ! ! !