Performance investigation of aluminised ANFO in limestone blasting operations

Abstract Limestone is an important raw material for the cement and concrete industries. Drilling and blasting are commonly employed in the production of limestone. Ammonium nitrate with fuel oil (ANFO) is an extensively used explosive and aluminium is added to improve the energy output. However, it is important to determine the correct amount of aluminium to add to enhance the blasting process. The optimum composition of aluminised ANFO (ALANFO) has been determined in a limestone deposit where 2 Mt year−1 of limestone is produced for a cement plant in Turkey. Field tests were carried out on the currently applied square drilling pattern of 3 m × 3 m and also the rectangular drilling patterns 3·0 m × 3·5 m, 3·0 m × 4·0 m 3·0 m × 4·5 m and 4·0 m × 4·5 m using ANFO and different compositions of ALANFO together with the other design parameters. Results of the tests shots were analysed in terms of fragmentation and costs. The use of ALANFO prepared with the addition of 15% Al powder on the 4·0 m × 4·5 m pattern resulted in improvements in fragmentation and 28% of savings in specific drilling and blasting costs in the studied quarry.