The use of air decking techniques for improving surface mine blasting

The improvement of the blasting pattern aims to maximize the use of explosive energy for better fragmentation and also reduce explosive material consumption and decrease the blasting’s undesirable effects. The power deck method is one of the new technologies in blast efficiency enhancement and cost reduction in surface mine blasts. For this purpose, firstly, the current blasts in the Anguran lead and zinc surface mine were analyzed. Then, the classification of rock zones was performed based on geotechnical properties. Also, new blasting patterns were designed based on different air deck shipments in blast holes. After calculating power deck placement parameters, six experimental blasts were carried out in the eastern and southern zones of mine as current conventional blasts (without power deck), single or double decks. For the next step, the rock fragmentation results of each blast were analyzed by Split Desktop software. Also, the analysis of power deck blasts was performed based on rock pile displacement, fly rock, specific charge, and specific drilling factors. As a result, the power deck implementation in surface mine blasts causes better fragmentation and uniformity of crushed rocks, with decreasing the bench throwing and toes, better rock pile displacement, and decreasing of fly rocks. From the financial point of view, using single and double power decks reduces the unit cost of rock volume up to 10.7% and 16.8%, respectively, compared to conventional mine blasts. Accordingly, a single power deck blasting with a 4.2 * 5 m pattern is proposed for the eastern and southern zones.