Limestone reserve calculation for engineering purposes for the Nfayil Formation (middle Miocene) in Bahr Al-Najaf Depression, Iraq

Abstract

      Limestones have considerable commercial importance because they are used as building stones and are widely used for flooring and interior and exterior facings. On the other hand, the reserve calculation reveals the economic effectiveness of the investigation. This study aims to calculate the reserve of the middle Miocene limestone for engineering purposes. The limestone beds of the Nfayil Formation in Central Iraq have been studied over 15 outcrop sections. The Nfayil bed has an average thickness of about 1.64 m, while the overburden has an average of about 0.93 m. The average bulk density of limestone is 2.1 gm/cm³. Kriging and triangulation method has been adopted and used in the calculation and assessment of reserve. The industrial layer was calculated based on the American classification, where the assessment is from the inferred reserve, which is according to the geological characteristics of the industrial layer, as well as the presence of a few wells obtained for the studied area (15 wells). The industrial bed's total reserve (tonnage) is 253,245,195 tons, which is acceptable for accuracy and reliability compared to the American system. These values are acceptable for the number of the studied wells.