The basics of blasting and requirements explained.
All mining operations require blasting at one stage or another. Blast hole drilling is used in mining where a hole is drilled into the surface rock, packed with explosives and detonated. The aim of this technique is to induce cracks in the inner geology of the surrounding rock, making deeper mining possible. The drilling of blast holes is traditionally used when the mine would like to explore the mineral composition or potential mineral yield of an area that is considered for future mining. Blast holes can be considered a fundamental step in the exploration process, but also as in the extraction of coal.
Blast hole drilling is specifically utilized in coal mining to break up the rock and hard minerals in order to extract the coal. But when it comes to coal mining, all seams are considered gassy and the degree of the gas present may vary from I to III. Methane gas is released during the coal mining process. And in underground coal mines, like the coal mines in Emalahleni, there is an increased risk as the coal dust can explode as a direct result of the ignition of flammable gases such as methane or operation induced by either blasting, machinery or faulty equipment.
“Ignition is caused by either one of the following- direct action or indirect action from the shockwaves created by the blasting itself, hot gassy products of the detonation mixing with the methane and air mixture and/or hot reaching solid particles of the explosives getting ejected into the methane gas mixture, “explains Johan Venter, Managing Director of CTC.
For coal mining, specifically designed explosives and detonators are required in order to ensure a safe blasting process. There are three types of permitted explosives, each group being designed for a particular type of operation for maximum safety. Detonators in conjunction with permitted explosives only approved detonators may be used for coal mine blasting. Blasting is done in a blasting sequence as well, as it breaks the rock surface evenly.
The Colliery Training College (CTC) in Emalahleni offers an internationally recognized Underground and Surface blasting qualification. The minimum requirements for this qualification are Gr11 with mathematics and English as subjects. When the basic training is completed, the student will receive a logbook to finish on the mine that the student is from, and for private students, CTC will arrange access to a mine for the student. When all modules are completed, a Board Preparation will be booked and a final practical assessment underground. After the learner has completed all of the following, the student will be allowed to make a booking for the DMR Blasting Board Exam.
To find out more about the basics of blasting, click here: https://ctctraining.org/coal-mining/blasting/
The basics about basting and the requirements explained