With the price of platinum at around $31,000/kg and even rhodium at about $10 000/oz, there is a lot of pressure on production crews in underground PGM mines to minimise dilution & maximise ore production. A poor blast means a shallow advance, uneven faces, over- and underbreaks and even falling rock. All of which takes time to clean and make safe. It could lead to a missed blast during the next shift cycle, at a production loss of nearly $20,000. And the target can be well over panels to be blasted every day.
Johan Bouwer, Head of VR & New Technology at South Africa’s sts3D told IM: “One problem in the industry has been the means to train crews effectively. Taking trainees deep underground takes time, plus it is a challenging and potentially dangerous environment. But how do you pass on decades of practical experience on surface using PowerPoint slides? How do you get the trainees to grasp the true scale, distances and measurements of a stope panel? You can’t build muscle memory on a scaled down, flat, two dimensional surface, plus just how do you assess them to make sure they’re really competent?”
Anglo American Platinum is one major miner that has embraced digitalisation and Industry 4.0 and advanced training is no exception. At its Tumela Training Centre in Amandelbult it has installed a combination of a 2,300 ft3 training space, surrounded by an immersive 800 ft2 rear projection screen – held in place by about 2,000 ft of aluminium tubing. One powerful PC drives 12 digital projectors and another monitors 20 state-of-the-art Vicon tracking cameras. All of this is brought to life by over 4,300ft of electrical and signal cabling. To make the VR project a reality, Anglo approached sts3D, a Pretoria-based company with over 15 years of experience in building safety training solutions for the mining industry. Boasting various Virtual Reality HMD (Head Mount Display) training programs, an immersive VR Cube, seven VR Blast Walls, and a VR Robotics Simulator, sts3D have made it happen.
Bouwer says: “The VR Stope is massive – it has a production face panel of roughly 16.5 ft wide, 5 ft high and 13 ft deep; an Advanced Strike Gully, or ASG, which is 9 ft deep, 9 ft high, and 5 ft wide, and to the right is a siding of 5 ft x 5 ft x 7.5 ft. And the challenge was similarly massive. But although designing and constructing the hardware, building the virtual stope, and coding the functions caused the sts3D team a few headaches, the really tricky part was how to track the users in real time within this multi-dimensional stope. This required breaking new ground, so sts3D, being new to motion capture, turned to the best in the industry for expert assistance. Vicon stood out with the depth of their response and their willingness to engage in an open conversation about how the system would work in the virtual mining environment – they provided clarity and assurance.
Vicon quickly allayed the concern that cameras might not be able to track if markers were occluded by users. When Vicon convinced sts3D that their solution could track the subject accurately as long as a marker was visible to a single camera, the solution was clinched. It was relatively simple to plug the Vicon sample data into the Unity game engine.
“Anglo American trains 1,500 people per year and must be able to operate the system on site without constant external support. Since a single instructor – without any prior experience in motion capture or Virtual Reality – only needs a one-button start to run the blast simulation, the Vicon system more than met the criterion of simplicity. And since the Vicon system can track up to five people at once, this enables team learning, and makes the training of big numbers of trainees possible – a must in the mining environment. This ability to track multiple objects through space provides very realistic training – preparing users for real conditions in the field.”
During entry examination, for example, miners must decide whether a zone is safe for operations. If they get it wrong, they get a realistic simulation of what could happen. A big loud bang and sudden darkness simulate a potential rock fall on the spot where they are standing.
“Make no mistake – this gives the miners a real fright – they’ll remember their error. Since you are fully immersed in the virtual mine, there’s no room for distraction – and the learning sticks. You’re on high alert all the time while marking a pattern on the rock face for the drill operators. And when you detonate the blast, the rock flies – creating a very vivid, a very memorable experience,” says Bouwer.
The VR Stope is a life-sized serious game. It has two modes – a training, and an assessment mode. In training mode users are instructed step by step how and where to mark off the panel using a special virtual paint brush. This builds muscle memory and motor skills, which will be recalled once back in the actual environment. The system provides immediate visual feedback on correct or wrong actions. The added ability to undo and retry allows for effective, short cycle, feedback and learning.
Once the user has completed marking and timing, they experience VR’s ‘art of the impossible.’ When the detonation is set off right in front of them, they see the firing sequence and fragmentation of the rock. It also enables them to inspect the quality of the blast first-hand – again and again, in real time or in slow motion, forward or reverse. The miners can now really understand how and why the correct blasting procedure works best.
After a blast, the cameras track the hard hat position of the trainee, adjusting the perspective of the projections. This creates a 3D depth illusion – showing that the face wall has in fact advanced. Trainees can then study the results of their blast, and immediately see if they have had a good or bad advance – another completely novel experience.
In the assessment mode, trainees mark the blasting pattern and time the detonation sequence of explosives themselves. Once the marking pattern is submitted, the system takes a screenshot of the trainee’s attempt. The image gets saved to their PDF report along with information on number of attempts, accuracy, the time taken and the number of times assistance was requested. Trainees also compete for Top Score Bragging Rights – a level of gamification that goes beyond tricks like badges and achievements and that assists in making learning stick.
In the next phase of instructional design and deployment, sts3D will cover Safe Entry Examination, testing for ventilation and noxious gasses, support installation and rock strata control – resulting in life threatening learning experiences – but again in an environment which is completely safe.
