The request was to design and supply a set of folding stairs for installation on the fixed gantry of a coal stacker.
Stairs such as these are typically installed on fixed gantries to provide access to the top of tankers. However, in this instance, the application was for them to be used to provide a safe access system for one of the coal stackers at the Mt Arthur coal mine.
Treloar Engineering Manager, Paul Walton, said there had been a long-standing challenge with this machinery, due to the uneven floor and varying heights as the equipment travels along the rails.
“The system currently in use means the four fixed steps attached to the stacker’s access platform cannot adjust to the variable height difference from the stacker to the ground on an uneven surface,” explained Paul.
“The conditions can also be highly variable, dependent on things such as rain episodes or track resurfacing.
“The solution was to develop folding stairs which would move with the stacker, which could be deployed in various locations and always make contact with the ground.
“We saw this as a great opportunity to, once again, work with WLT, as they have some unique systems and are always willing to think outside the box.
“After some initial design work, we developed a concept which looked promising. However, there was a degree of scepticism and concern among some of the safety officers regarding the operation and potential for injury when using the stairs in this application.
“We decided the best way to put their minds at ease was to build a test platform, mount the stairs and let them trial it in the comfort of our workshop.
“This was also a great opportunity to have everyone’s contribution to possible design improvements.
“During the visit, the safety officers were surprised that the stairs were fully self-supporting, they expected the solution to be similar to a fire escape.
“They were particularly impressed that the design solution meant the contact bar at the bottom of the stairs always rests on the ground, removing the previous issue of the varying distance to the first step, and significantly reducing any injury risk.
“They were pleased with the design and the material selected for its suitability for use on mine sites. They also liked how sturdy and easy to use the design was, and the attention to detail exhibited.
“The workshop visit enabled the safety officers and the Treloar team to thoroughly analyse and devise improvements.
“Following the initial demonstration, we took their feedback on board and identified some unique features which could be added to the design to take safety to the next level.
“In normal use on tankers, these types of stairs are accessed from the top, so they are always lowered and raised from the top of the staircase. However, in this instance, we had to ensure the lowering and raising mechanism could also be activated from ground level.
“The most important design modification related to this issue. We devised a simple handle that actuates the foot lock at the top of the stairs. The handle has a shroud around it, so the operator is forced to stand to the side of the stairs when lowering. This safety feature ensures they cannot be trapped beneath the lowering stairs. We also incorporated a safety handrail that can be held onto while lowering the stairs.
“The modified stairs have been delivered and are ready to be installed around September this year. BHP will trial them on the first stacker and, if successful, will order a set for the second stacker.
“We are now looking to how this design could be adapted in other situations, including on large earthmoving equipment, such as dump trucks and dozers. It’s a unique solution to an issue which presents in various forms on worksites around the world every day and could enhance workplace safety in many situations,” concluded Paul.