Haul roads are primarily used for the transportation of mined raw materials to processing plants and sometimes to waste dumps. The crucial elements of road engineering should be incorporated when designing haul roads. A Haul Road Development Program sets the benchmark for what a good haul road should entail and how to go about the process of construction. When haul roads are properly maintained, there is efficiency in operations. A mining company doesn’t have to worry about expensive repairs which could jeopardize the operation. When designing haul roads, there are a couple of factors that will need to be taken into consideration.
The parameters of the road will be limited with the agility of the largest vehicle on the construction site. Haul trucks will be the heaviest and slowest vehicles on site. When designing the road, the haul truck size, turning angles, and braking capabilities should all be taken into consideration. Speed is an important factor when looking at the design of a haul road. Some of the main design parameters will include:
· Mining area surface roads
· Ramps
· Plant site and administration
· Workshops
These parameters will also be applicable in the case of temporary haul roads.
Stopping Distance
This can be defined as the minimum distance that will be required for a vehicle to stop. This factors in the design speed even if it is a sudden stop in case of a hazard. The driver’s reaction time and the slowing action will be taken into account when determining the stopping speed. The stopping distance will vary depending on the vehicle in question. The vehicles with the lowest braking capacity will form the baseline when coming up with the recommended braking distance for site.
Sight Distance
This is the distance between the object and the carriageway. It could also be the distance between two drivers and the carriageway. There is a strong correlation between stopping distance and sight distance. This is because, in both instances, the distance between the driver and the hazard ahead should be more than enough to bring the vehicle to a sudden stop. The sight distance will be defined by:
· The lowest vehicle using the haul road
· Stopping distance for the largest vehicle on the site
· Design speed for the haul road
Sight distance will come in handy for vertical, horizontal curves, and also at the intersections. If it is a horizontal curve, the sight distance could be interfered with by trees, structures, and even rocks. Too sharp of verticals could also create the same kind of problems. An easy solution to this predicament would be to smooth the crests which ultimately increases the sight distance. When it comes to the intersection, the solution would be to maximize the distance for traffic coming from all sides. There shouldn’t be a lot of restrictions where there are bends. If it has to happen, the restrictions should be kept to a bare minimum.
Road Width
The width will also play an important role when designing a haul road. There should be ample space for even the largest vehicle on the site to easily maneuver around. This is a simple design consideration that will not only increase efficiency in operations but also improve safety on the site.
Narrow roadways can create uncomfortable driving situations which can sometimes lead to mistakes from the truck drivers. This could potentially slow the traffic on the site thus leading to an increase in production cycle times. There should be adequate clearance between vehicles to minimize the risks of accidents happening. The reason why road widths are specified is so that such risks can be mitigated.
Those areas that have curves need to be widened to take into account the largest vehicle on site.
The same considerations will be applied even when designing a temporary haul road. The number one priority is safety on the site. The roads should be able to promote efficiency in the production line. Another aspect that is often overlooked is monitoring and maintenance. This can be a challenge, especially when dealing with a large mining site. Relying on humans can be a tad too challenging as it will be hard to spot all the issues. As a mining company, you should be investing in haul road monitoring systems. This will ensure that the vehicles are moving at the recommended speeds and the potential issues are uncovered before they become a hazard. Getting the design right from the onset will ensure that there are not a lot of issues when it comes to monitoring and maintenance.
