An Assessment of Drilling and Blasting Techniques at the Granite Quarry of AFDIN Construction Company Limited, Katsina State, Nigeria

Abstract

This research work assessed the Drilling and Blasting Techniques at the Granite Quarry of AFDIN Construction Company Limited, Katsina State, Nigeria. The objectives of the study were to identify drilling and blasting equipment, find out the drilling pattern and parameters, assess the blasting method and its compliance with safety practices in and around the blast site, and review the impact of the blasting operations on the surrounding environment. The concept of drilling and blasting activities and how they affect the immediate environment were examined. The study assessed quarry activities using field visits and interviews. Equipment identified at the quarry were wagon drill, jackhammer, compressors, rock breaker, excavators and tippers, etc. Also, Atlas Copco YT27 jackhammer was the main tool for hole drilling with either square or rectangular drilling pattern being adopted, and drilling dimensions of 4x5ft or 4x4ft (spacing and burden) were frequently used at the quarry. Hole depths used were 6ft, 8ft, 10ft, and 12ft and drilling bit of 1-inch or 2-inch. The study estimated that 2,088.95 kg of explosives (10% high explosive and 90% low explosive) was used to charge 2000 drilled holes with an average hole depth of 3.65metres and a diameter of 32mm respectively. A total of 7,394 tonnes of granite rock was blasted. Results from immediate blasting at the quarry indicated the presence of dust and fumes within the quarry environment and nearby villages, inhalation of which could lead to serious occupational hazards. Conclusively, explosion sound from blasting and fly-rock fragments were found to have some serious environmental and health effects on both workers and neighbouring communities in terms of noise pollution and vibration effects on structures. Dust suppression of the environment by continuous wetting of the ground and crushing process was recommended to minimise dust generation to protect workers from occupational diseases such as silicosis and Pneumoconiosis. Wearing of personal protective equipment, electric blasting method, corporate social responsibilities to the communities were also recommended.