SURFACE LOADING
From the very latest news on the latest rope shovel designs, to new electric wheel loaders, Paul Moore gives the lowdown on surface loading technology
Moving more muck
As the mining industry starts to climb out of its depression, open pit mining organisations are striving to improve productivity wherever possible. One area that has large potential optimisation gains is in the excavation load cycle, as inefficient truck spotting while loading and dumping can impact a mine’ s productivity. Modular Mining Systems Inc told IM:“ While this challenge has gone largely unresolved historically, new and emerging operator assist technologies may finally provide the solution that mine operators need to improve productivity while loading and dumping.”
The load cycle plays a critical role in the production process of an open-pit mine, and can dramatically influence a mine’ s overall profitability, making it a key target for optimisation. Modular states:“ Since loading units can directly influence the utilisation of haul trucks, optimising a mine’ s excavation load cycle also optimises its high-cost equipment and minimises total truck wait time at the shovel by maximising material movement, increasing truck utilisation, and decreasing the required fleet size for a given target production.”
An ideal load cycle is one that minimises shovel hang time, optimises shovel swing angle, maximises trucking capacity, and allows for greater compliance to plan.“ But accomplishing this ideal load cycle is not an easy task, as the efficiency and safety of haul truck manoeuvring at shovels, crushers, and dumps varies dramatically with operator skill. Increasing employee turnover and the lack of available and recruit-able skilled operators further
complicates the variability of operator capability across a mine site. As a result, mines often employ standard operating procedures geared towards the lowest level of capability to ensure a safer production; traditional practices such as bucket spotting and single-side loading can reduce the risk of truck-shovel impacts, but at the cost of productivity, as the resulting increase in shovel hang time reduces the productivity of both shovels and trucks.”
Additional challenges that haul truck drivers often face in truck-shovel interactions include the difficulty of determining the correct approach to radial equipment, working in a highly distracting and very dynamic shovel area, and a lacking understanding of the shovel operator’ s preferences( ie desired spot side, location, and heading).
“ Load cycle optimisation is further complicated by siloed approaches by operations, engineering, safety, and training departments within an organisation, who often focus only on specific portions of the load cycle, rather than the cycle as a whole.”
New operator assist technologies
Modular believes that operator assist technologies can help the load cycle optimisation effort by potentially equalising the performance of all operators to a capability close to( or even beyond) that of the most experienced operator.“ An operator assist system that approaches optimisation holistically by considering the load cycle as a whole will provide the aforementioned benefits while also
The hybrid Komatsu Mining P & H 2650CX at ASARCO Mission copper mine, USA. A target to reduce fuel consumption by up to 25 %, in comparison to a 550-700 t hydraulic excavator, has been successfully realised
accounting for such factors as safety, bench design, truck spotting, truck and shovel size, environmental factors, operator skill level, and single- or double-sided loading.”
Modular Mining Systems has recently developed an operator assist technology, called Guided Spotting, that it says has the potential to significantly improve both shovel and truck productivity in open pit mines by improving visibility and efficiently guiding haul truck drivers, while reversing their truck towards the shovel loading position, without guidance from the shovel operator.
“ The Guided Spotting system was built on the success of Modular’ s ProVision ® machine guidance solution for excavators, released nearly 20 years ago, and utilises the ProVision solution’ s same advanced guidance technologies and high-precision GNSS positioning to assist truck operators in efficiently spotting at load and dump locations. The Guided Spotting technology has undergone extensive field trials at a large open-pit copper mine in Utah and will be released later this year.”
The technology has already demonstrated the ability to: n Increase shovel productivity by 4 to 35 %
( 9 % on average) n Contribute 2-8 additional loads per hour
58 International Mining | MARCH 2018