ABSTRACT: It is important from the economy point of view to be able to estimate the mean block volume obtainablefrom a rock mass in block stone quarrying operations. In the first stage of this study, the mean blockvolumes likely to be obtainable from the Mesozoic limestone quarries of the Karaburun Peninsula areestimated by analyzing the discontinuity measurements made in these quarries using the equation givenin literature. It has been found that the rock block designation method (BQD) proposed by the authorhas given closer results to the block volume values estimated using the volumetric joint count (Jv) as Vi= 36/Jv3 among the suggested block volume estimation method given in literature. In the second stage,the mean block volume (Vb), the volumetric joint count (Jvb) and the block shape factors (βb) values of2378 blocks produced from the working quarries of Karaburun Peninsula are compared with the meanblock volumes (Vi) and the volumetric joint counts (Jvi) estimated by using the field discontinuity spacingmeasurements. Relations are given for estimating the mean block volume producible from a quarry usingthe field discontinuity spacing measurements and they are presented as a graph for general use.