Safety has assumed an increasingly important role in South African exploration and mining projects in the past years, and much of the increased focus on safety has been due to very onerous legislation passed by the government that regulates mining operations. All drilling operations and activities in mines are regulated by the Mine Health and Safety Act.
Recently, CTC was approached by a large coal mine close to Secunda to drill four ventilation boreholes at a fully operational mine. The scope of work comprised four 660mm diameter holes, normally used for rescue purposes. Each hole is lined with an 8mm steel casing through the soft overburden. The holes will be equipped with ventilation fans to augment the existing ventilation arrangements of the mine. Work on the boreholes commenced on the 4th of September 2018.
The CTC team worked closely with the Mine Rescue Services team on the drilling of the holes and ensuring that the project’s completion reached a safe stage. The team used reverse circulation drilling. One of the main deciding factors on the use of reverse circulation drilling is that the team would be able to drill through the number 2 seam had it been mined in the past, into the number 4 seam that is currently operational. Conventional drilling is not able to drill through such cavities, whereas using this method makes it possible. Noteworthy achievements of CTC drilling and mining training projects include a record of 16 Lost Time Injury Free years up to date, which was celebrated in August this year.
Equipment deployed on the project by CTC includes a Schramm T130XD Main drill rig as well as a number of trailers that contain ancillary equipment. The unit also employs a T685WS Pilot drill capable of drilling a 220mm hole through the soft overburden after which casing is inserted. A 165mm diameter uncased hole can then be drilled to a depth of 300m. The T130XD is capable of drilling on a larger scale- 750mm simultaneously inserting a 710mm diameter casing to a depth of 300m. All equipment is serviced in a comprehensive workshop by the well-trained team of CTC to ensure operational excellence and adherence to strict safety measures.
Written by Heleen Tshibumbu for the Colliery Training College 2020
