Quarrying has long been a part of South Australia’s history.
The Mount Lofty Ranges have been quarried since 1837. For more than 180 years the east coast of South Australia has been providing the nation with rich aggregate materials to build and support the growing need for infrastructure.
Demands for aggregate materials have changed vastly over the past 180 years, differing enormously from the small quarries that supplied stone to build houses for colonial settlers. The quarries that now provide building materials for a much larger and ever-growing population introduce a higher demand for output tonnages, founding a need to increase efficiency and productivity on site.
A large quarry in South Australia was experiencing difficulty equipping its belt conveyor system with the products necessary to handle the increase in tonnages. The quarry was experiencing severe belt wear and spillage around the load zone, with damage to the structure from the impact energy of the large rock being conveyed.
1500-tonne-per-day belt
The most difficult challenge was a critical conveyor, which feeds the secondary crusher, so achieving optimum efficiency was a matter of great importance for the site’s operational managers.
The average rock size that fell onto this conveyor was about 50kg, falling from a height of four metres onto a 19mm thick and 1200mm wide belt running at three metres per second.
This belt saw 1500 tonnes of rock per day. When 1500 tonnes of material hits the same spot every day, from a height of four metres, without the necessary support, it’s no wonder the belt and structure becomes severely damaged.
The impact bed that was originally installed was not strong enough to support the extreme tonnages the load point saw day in, day out. As a result, the idler frames would break every few weeks and the belt quickly became severely damaged – to the point of needing replacement.
{{image2-a:r-w:300}}The idler frames would also have to be replaced every four to six weeks, with shutdowns occurring at the same rate, to replace the frames and repair or replace the belt. The belt was replaced and upgraded multiple times to try to combat this issue.
This constant cycle of maintenance and repair amounted to 24 hours of downtime per month. Not only did the shutdowns occur to replace broken belt conveyor system components, but also to clean up the mass amount of spillage that was occurring – from the overflow of material that could not be contained by the impact bed and skirting system.
The site sought the help of Flexco specialists to source or create a solution to the problems that were placing time, monetary and productivity burdens on the site’s operational managers.
An impact bed based on Flexco’s DRX impact bed range was designed and manufactured in Australia.
Traditionally, DRX impact beds are available in four sizes, dependent on impact energy (200, 750, 1500 and 3000). However, for this application, the impact energy was far greater than the acceptable and safe standard of the largest DRX 3000 bed, so a custom solution was made with extra support in the impact energy absorbers.
DRX models feature velocity reduction technology, which ensures a level of protection like no other, resulting in less belt wear and damage, less rebound and material degradation and two levels of impact absorbing force reduction.
Ease of service is another important factor, as the DRX bed separates in the middle, allowing the two sides to slide apart, providing access to all the bars and bolts for quick, easy and safe maintenance.
Due to the structure, there was not enough room for two impact beds to be installed at the load zone, so Flexco engineer Jan Olwagen created heavy-duty CoreTech impact rollers, which could take on the impact outside the impact bed’s reach.
After the custom DRX 4500 bed was installed, the site experienced a significant improvement in productivity.
The most impressive difference in operation was that the belt could now run 24/7.
Since the product was installed on 28 December, 2017, the site has performed planned maintenance and scheduled shutdowns only. This results not only in higher output tonnages, but also less need for maintenance, meaning maintenance crews can attribute their time and knowledge to other areas of the site, instead of reacting to the same issue repeatedly.
Now the new impact bed is more than adequately supporting the tonnages seen by the belt, there hasn’t been a need to replace the idler frames, impact bed support bars or, most importantly, the belt in more than six months. Not only does this save time for the quarry, but also a huge amount of money, which can be allocated towards funding upgrades for other areas of the site.
Source: Flexco Australia