Risks and Hazards in Drilling and Blasting

There are risks and hazards involved in drilling and blasting operations. Drilling hazards include rotating and moving parts such as drill rods, drill strings and rod handlers. The direct risk factors include exposure to rotating or moving parts which have contributing risk factors such as inadequate or lack of safeguarding and severity of the risk can lead to amputation and scalping.

Compressed air is by far the most dangerous of all fluids used in the drilling industry. To put this into perspective, unlike oil or water, a given volume of air can be reduced by compression, which can be likened to a compressed spring. The uncontrolled release of stored energy can be lethal. An example is debris from blown hoses can travel at speeds such that there is no time to react.

Hazardous substances and dangerous goods such as diesel, petrol, acids, oils, and grease can lead to spills and leaks which present a fire hazard. Exposure to hydrocarbons may result in dermatitis and other illnesses. Contact with acids can cause chemical burns. Spilt or leaking oil and fuel can present a slip hazard to workers. Spilt hydrocarbons can also attract dirt and dust from the drilling operations, which makes detecting and monitoring of leaks difficult.

Manual tasks undertaken during drilling operations include physical work such as lifting, lowering, pushing, and pulling. Repetitive actions like hammering, sustained postures and concurrent exposure to vibration can lead musculoskeletal disorders. Drilling operations generate substantial amounts of dust. Dust results in long-term health effects such as lung disease, systemic toxicity, and irritation of the respiratory tract.

Hazards in the drilling and blasting process includes the presence of some ground structures such as hard rock boulders and voids, heavy seepage of ground water into the blast-holes, blast-holes that have high temperature within them and deviation of blast-holes.

Commonly used explosive ANFO has the AN component that dissolves in water leading to a feeble blast on no blast occurring at all. Hot blast holes create temperature zones which can lead to explosive deflagration or detonation immediately or after some time.

Hazards of the blasting process include misfires, ground vibrations, air blast, fly rocks, air pollution and environmental changes. Misfires occur when a charged blast-hole does not explode or when a part of explosive column in a blast-hole has not exploded along with other blast-holes. A neglected misfire can suddenly explode which presents risks and hazards to the environment and can lead to fatalities.

On blasting an explosive in a blast-hole, the chemical reaction evolves a huge quantity of energy. The ground vibrations radiate out from the blast-hole, the intensity continues to reduce and at long distance it becomes too low to be perceived. At nearby distances the ground vibrations have sufficiently high energy to shatter many structures firmly embedded into ground.

Air blast, often called air overpressure because the rapid movement of rock mass, and the ejection of gases under extremely high pressure. These air blasts can lead hearing loss in humans. Buildup of excessive pressure within the blast-hole exerts a propelling force on the pieces of rock and makes them fly like a projectile. Direction of fly rock is very unpredictable.