Determination of open pit base boundaries in C and D sectors at Afşin – Elbistan coal basin with indicator kriging

When the lignite coal resources in Turkey are analyzed, Afşin - Elbistan Coal Basin in provincial borders of Kahramanmaras has significant energy generation potential in Turkey with about 4.8 billion tons of coal resources. When the spread of coal seams at Afşin – Elbistan Coal Basin analyzed generally, it is understood that as can be seen in A and B sectors previously put into operation, coal in C and D sectors can be produced economically with open pit coal mining too. With this study, it is aimed to determine suitable regions for production with open pit in C and D sectors at Afşin – Elbistan Coal Basin. To that end, using the existing borehole database of sectors C and D, cumulative stripping ratio in vertical direction was determined at each level that cuts coal for each borehole primarily. These stripping ratio values are added to the database as an attribute. The average of the stripping ratios in the last 10 years at Kışlaköy (Sector A) mine, which was previously commissioned in the basin and has been producing coal with open pit mining for about 35 years, is about 2.8 m3 / ton and this value is accepted as an economic limit value for the design of open pit that will be constituted in C and D sectors. In addition to the stripping ratio values, a second criterion suitable for open pit base inclination is determined by considering the elevations of the coals at the lowest levels in the boreholes. This criterion is defined as the inclination between base coals of the two adjacent boreholes to be less than 4%. For open pit mining, the two-dimensional indicator variable is derived across sectors by binary coding the boreholes which are suitable for open pit mining that meet the above mentioned two criteria as "1" and the non-matching boreholes as "0". The spatial probability distribution of the possible open pit base boundaries across sectors C and D is determined with indicator kriging by using these variables being as is point.