There are many reasons that your mine will encounter hang time, including inexperienced truck operators, site requirements for bucket spotting, night time and adverse weather conditions, “cowboy” operators who are experienced yet don’t always put the truck in the right spot, and more. Regardless of the reason, hang time consumes valuable cycle time that you can’t get back. But what if you could? What does 15 seconds of hang time really mean for your mine, anyway?
Hang time resulting from truck spotting
An ideal load cycle:
- Minimizes shovel hang time
- Optimizes shovel swing angle
- Maximizes trucking capacity
- 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 maneuvering 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 your site.
As a result, your mine probably employs 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 (i.e. desired spot side, location, and heading).
Hang time as a result of bucket spot requirements:
Hang time as a result of truck re-spotting:
Defining the size of the prize
Using a conservative 15-second estimate as an example for hang time at a typical mine, let’s break down the true cost of hang time.
15 seconds of shovel hang time:
x 13 loads per hour
= 3.25 minutes of lost capacity/hour
x 20 hours per day
= 65 minutes of lost capacity/day
x 365 days
= 395 hours of lost capacity/year
x 6,000 tons/hour (shovel production rate)
= 2,372,500 tons/year
Getting to the right spot the first time
So how do you minimize shovel hang time at your mine? Active guidance to help your truck operators get to the right spot, the first time, is a good start. And several systems are available to the mining market today, which promise to do just that.
But before you invest in one of these technologies, you should make sure it will complement your existing practices, rather than seeking to replace them – in other words, don’t force your operators to stare at a camera screen when they’re used to relying on their mirrors and situational awareness.
Expecting a camera system to guide operators at night, or in dusty, rainy, or muddy conditions, is also a risky move, and may end up adding to your hang time, rather than detracting from it. And camera-based systems require yet another display to be mounted in your cab – you don’t really want that additional clutter, do you?
The ProVision® Guided Spotting system, which was recently deployed commercially at a large mine in Africa, 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 system leverages LED light bars, mounted externally near your haul trucks’ side mirrors, to encourage continued mirror use without detracting from your operators’ situational awareness. The displays are both simple and intuitive, providing high-precision, real-time guidance without distracting or requiring analysis, as soon as your truck enters the pre-defined load zone; since your truck operators don’t need to interact with the system whatsoever, they can continue to focus their attention on their mirrors and situational awareness.
Leveraging the ProVision Guided Spotting system:
This latest installation of the Guided Spotting system will help the mine increase productivity by facilitating double-sided loading, reducing the occurrence of truck re-positioning, increasing operators’ situational awareness, optimizing swing angle, and reducing shovel hang time. In the future, mine sites will also be able to use the Guided Spotting technology to optimize crusher dumping, dozer assist truck spotting, paddock dumping, pantograph guidance, lane-keeping guidance, and more.
To learn more about the ProVision Guided Spotting system,
contact your Modular Mining account representative
or click here.