An Assessment of Drilling and Blasting Techniques at 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 were to identify drilling and blasting equipment, find out the drilling pattern and parameters, assess 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. As an introduction, the concept of drilling and blasting activities and how they affect immediate environment were explained. The study assessed quarry activities using field visit and interviews. Equipment identified at the quarry were Wagon drill, Jack hammer, Compressors, Rock breaker, Excavators and tippers, etc. Also, Atlas Copco YT27 Jack Hammer 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. Furthermore, the study identified 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 diameter of 32mm. A total of 7,394 tonnes of granite rock was blasted. Result from immediate blasting at the quarry indicated presence of dust and fumes within the quarry environment and nearby villages, inhalation of which could lead to serious occupational hazards. Conclusively, the explosion sound from blasting and fly-rock fragments have some serious environmental and health effects to both workers and neighbouring communities in terms of noise pollution and vibration to structures. Wetting the environment and crushing process was recommended to minimise dust generation to barest minimum to protect workers from occupational diseases such as silicosis and Pneumoconiosis, also wearing of personal protective equipment, electric blasting method, corporate social responsibilities to the communities were recommended.