A group of South African rescue trainees heave and gasp after crawling through a narrow steel pipe, in a dark, smoke-filled mine shaft -- but commands shouted by an instructor urge them onwards.
"Number four, what is your oxygen reading?" he yells. "170, captain," comes the muffled answer from behind an oxygen mask, the exhausted trainee at pains not to sound weak. Few make it into the elite squad of the Mines Rescue Services (MRS), dedicated to saving lives in a country with the deepest mines in the world.
‘Mines Rescue Services (MRS) members are regularly called out to help in South African mines, a country dotted with gold, platinum, coal and diamond mines. It's a voluntary service that requires fierce fitness and mining expertise.’
The trainees have only one shot at becoming a "brigadesman", as the rescuers are known. There is no second chance if you fail the initial one-week training course. The eight candidates, already down by two men, are linked at the waist by a harness.
They navigate along the claustrophobic, winding pipe on their stomachs, with 14.8 kilogram (32.6 pounds) of breathing apparatus on their backs, testing their tolerance for confined spaces and ability to work in a team.
Other drills involve climbing steep stairs underground in full rescue kit and throwing 25 kilogram sandbags and steel bars over a 1.5 metre (nearly five feet) wall. "We usually start with a group of about 10 or 12 guys, but only about six or seven finish the course," said assistant superintendent Gerrit Beukes.
The gruelling training could be mistaken for army exercises, preparing the recruits for precarious rescue missions underground where they fight fires and retrieve mineworkers trapped by rockfalls and other disasters. "We are working with people's lives, there is no room for mistakes, that is why we cannot lower the training standards," Beukes told AFP.
- In the line of duty -
In a country dotted with gold, platinum, coal and diamond mines, MRS members are regularly called out to help. It's a voluntary service that requires fierce fitness and mining expertise, which is why all brigadesman are required to be active mineworkers and to take regular refresher courses.
There are about 900 of them across the country, ready to be activated at a moment's notice during times of disaster. They are paid a small retainer on top of their miners' salary, plus an hourly rate when on an emergency call-out.
"I never felt like quitting. I could do it a hundred times over," said Pierre Pieterse at the end of a second day of training. "Danger is always there but you have to make a dangerous situation safe before you enter. It's about helping others," the 35-year-old production supervisor said.
Some women have taken the brigadesman test, but none have passed in the rescue service's 92-year history. Chief executive Christo de Klerk said although incidents in South African mines had declined since the early 1990s, emergencies still occur.
"This is one of the toughest professions that you can get," said De Klerk, noting that 37 brigadesman have been killed in the line of duty. "We try not to get emotionally involved, but there is nothing more gratifying than saving a person. We feel like we have accomplished a task and then move on."
- Dangerous illegal mining -
De Klerk said that as South African mines were so deep, the rescue service had its own unique machinery capable of reaching 3,000 metres underground. The drive for better rescue equipment was spurred by South Africa's worst mining disaster, in which 435 workers were killed at the Coalbrook mine in 1960.
The work of the brigadesmen has of late been by stretched by the growing trend of illegal mining, where diggers sift for gold in disused shafts. "At this stage we are more active trying to recover illegal miners than we are on our active mines," De Klerk said.
"It is really a major, major problem." He recalled an incident in May 2012 where the service was called out to a disused mine and saved 22 illegal diggers over a three-day period.
"Unfortunately we have similar incidents where we have to recover dead bodies." According to the Chamber of Mines of South Africa, annual fatalities in the country's mines have dropped from 615 in 1993 to 77 in 2015, with thousands injured.
In a high-profile tragedy in February this year, three mineworkers were trapped underground inside a steel shipping container used as an office after it was swallowed by a sinkhole at a mine in the east of the country. Eighty-seven workers survived, but after desperate attempts to reach the container, rescue efforts were suspended for safety reasons and the three remain buried.