Effect of layer thickness of rocks on blast fragmentation -- case study in a limestone mine.

The paper discusses the influence of layer thickness of limestone beds on blast fragmentation in different blasting benches of Aditya Limestone Mines of UltraTech Cements Limited. Blast fragmentation analysis was carried out using photographic method to determine the mean fragment sizes. Good correlations were obtained between average layer thicknesses and blast fragment size, power factor (t/kg) and charge factor (kg/m3). Mean fragment sizes less than 100 cm were obtained with the average layer thickness of limestone beds less than 80 cm. The powder factor more than 14 t/kg was achieved with layer thickness less than 200 cm. However, in geologically disturbed limestone strata, blast design patterns and joint parameters had significance in achieving desired fragment size. [ABSTRACT FROM AUTHOR]