Estimation of lignite reserve in the Kalburcayiri field, Kangal basin, Sivas, Turkey

This paper addresses a case study on global estimation of lignite reserve i n the Kalburcayiri field from the Sivas-Kangal basin, which is one of the m ost productive lignite basins in eastern Anatolia, Turkey. The two lignite seams, which were developed in a fresh-water lacustrine depositional enviro nment during the Pliocene time, are currently being exploited in the Kalbur cayiri open-cast mine for feed coal to a power plant with 300-MW capacity. Tonnage, thickness and quality parameters (ash yield, total sulphur content , and calorific value) of the lignite are variables considered in this stud y. The global estimates of these variables together with 95% confidence lim its are obtained using the approximation principle of global estimation. A random stratified grid is fitted to available boreholes; the variograms for thickness and lignite quality parameters are estimated and modeled. The mo dels are used in calculating estimation error variances that will later be used in constructing 95% confidence intervals for the true values. (C) 2001 Elsevier Science B.V. All rights reserved.