Chris Ryde, a senior maintenance planner at BHP Billiton’s Area C iron ore mine, was recently recognised at the company’s in-house Oscars for his development of a safer and faster way of changing belts on the mine’s ROM conveyors. ABHR editor Charles Macdonald spoke to Chris.
Located 92 kilometres north west of Newman, Area C is one of BHP Billiton’s seven Pilbara iron ore mines.
Chris Ryde has been at the fly-in fly-out site for 4.5 years and in his current role of senior maintenance planner for fixed plant maintenance looks after all conveyor-related repairs and maintenance on site.
Chris said that on an average day he would conduct “optimisation and shutdown meetings to see the shutdowns we have ahead of us, what work we have in there, and that we have the right parts and labour for shutdowns going forward. We also check interactions if there’s a part of the plant that’s going to interact with another.”
Safety is the top priority for Chris and the 15 maintenance planners that he supervises. Every day, at a 6am meeting, the team discusses field leadership in the plant and any hazards that have cropped up. More generally, every meeting starts with a safety share.
At Area C, full plant shutdowns are held every 12 weeks, with up to 800 contractors on site.
Belts are changed on the site’s three main run of mine (ROM) primary belts every 2.5 to 3 years and on “regular” fines belts at intervals of six months to a year.
The primary belts are 600 metres in length and thicker than the faster running fines belts.
As a maintenance planner, Chris and his team have to be well prepared before shutdowns.
“We have to make sure that we have belt onsite well before the shutdown and that our consumables, our splice kits are in date and on site, as well as everything that goes along with it skirt liners, scraper parts,” he explained. “Pretty much everything is replaced when you change a belt out; we give the conveyor a birthday.”
Changing a belt on one of the 600 metre ROM conveyors is challenging, with the belt weighing 60 tonnes and access impossible at the tail of the conveyor. The old changing method was unsafe.
“We used to have two large floats, like big trailers, a Mack truck with a big, long float on the back. We used to put belt winders on the back of those and reverse them under the conveyor system, because we had no access at the tail as it’s the ROM,” said Chris. “So you have a 60t tonne roll spinning around with an operator on the winder on the back of the float. I’ve operated it myself and it’s not really a good feeling.”
Chris’ concerns alluded to the fact that two operators had to work on the back of the floats in order to operate the hydraulic controls of the two belt winders. Further risk was introduced as a result of the two winders having controls that were not coupled in any way, so that if either winder was being rotated the other would remain fixed and did not spin until directed to do so by its operator.
Simultaneous control of the two winders relied upon communication between the two operators managing each of the two winding mechanisms. If this control failed, then there was a risk of one or both belt winders becoming unstable, toppling over and falling off the float since the winders were only held in place by chains and the winder footprint was larger than that of the float. In addition, the floats tended to sway under the motion of the winders, not only making the job uncomfortable for the two workers but adding to the risk of the winders toppling.
Chris drew inspiration for a safer change-out method from the practice employed on Area C’s 14km overland conveyor. It, like other overlands, used turning frames. These devices incorporate large rollers. Angled at 45 degrees, they allow the belt to fold over the roller and change the belt’s direction to 90 degrees, or other angles, if desired.
“We were replacing (the belt on) our overland conveyor last year and we were using these turning frames. When the belts are all flaked out and joined together on the ground, they are turned on through a 90 degree turning frame,” explained Chris.
The new system sees two conveyor belt winders positioned on the ground at 90 degrees to the conveyor system and in line with turning frames. The latter items are mounted on stands that are bolted to the conveyor structure.
“We thought there must be a way to bolt them down to a conveyor system if we made up some sort of frame, that we can remove the frames at the rollers and bolt down into their holes, so we can actually fix it on top of the structure.”
With a concept in mind, Chris provided a quick sketch to his engineering department. This then initiated a “Management of Change” procedure addressing risks to the structure.
“From there we engaged a contractor, Belle Banne, to help us fabricate a frame that can bolt on to these turning frames,” said Chris. “We trialled it on one of our ROM belts at the beginning of the year and it delivered straight away – the frame lined up to the idler holes perfectly, there were no hiccups at all. That job went from a 60 hour change-out job to 48 hours.”
In practice, the new system works as follows: in advance of the shutdown, the two conveyor belt winders are positioned on the ground (new belt reel and empty reel for old belt to reel on), at 90 degrees to the conveyor system. These are aligned with the turning frames as they are positioned on the conveyor module. This step is executed weeks before the shutdown to reduce the time required throughout a shutdown.
During the shutdown, the conveyor belt is clamped and cut and belt ends are moved away from the structure by crane. The turning frame mounting stands are then fixed to the system.
The new conveyor belt is then attached by a pulling plate to one of the old conveyor belt ends through the turning frame. The second conveyor end of the old belt is then put through the second turning frame and attached to the remaining belt winder. The conveyor belt replacement can now commence. The new belt is fed off the winder through the turning frame and onto the conveyor system while the other winder is pulling off the old belt.
Looking back on his initiative, Chris is happy with the support that he received from management. “Being a planner, I was able to project manage this initiative right through to the end,” he said. “Management lets you drive these initiatives yourself and gives you any support you need to make these things happen.”
Looking to the future, Chris says the improved belt changing method has branched off into several other initiatives. “We’re eliminating having any work at all from the back of a float or truck and also any home-made or un-engineered equipment. All these should be completely eliminated,” he said.