Prediction of mechanical behaviour from mineralogical composition of Sakesar limestone, Central Salt Range, Pakistan

Petrographic and mechanical properties of early Eocene Sakesar limestone have been investigated to establish the relationship between these parameters. Microscopic study revealed the presence of micrite (51.38%), sparite (12.90%), dolomite (12.95%), and allochems (20.88%) in the limestone samples. The strength parameters such as unconfined compressive strength (UCS), point load test (PLT), and Schmidt rebound hammer values (R n ) were determined in the rock mechanics laboratory. Regression analyses were carried out to establish correlation between limestone constituents and the strength parameters. The UCS and other mechanical properties showed moderate inverse relationship with sparite and allochems, whereas micrite and dolomite indicate a positive correlation with UCS. To get significant correlations for cumulative micrite + dolomite and sparite + allochems, percentages and strength parameters were arranged in decreasing order. The fixed threshold for the cumulative values of micrite and dolomite were ≥80, 70–80, 60–70, 50–60 and <50%. Percentage of these constituents and the corresponding mechanical parameters were arranged on these thresholds. The cumulative modal constituents of the limestone were plotted against the mechanical parameters. Correlation among these values allowed developing equations for prediction of mechanical behaviour from mineralogical composition of Sakesar Limestone with more than 95% accuracy.