The (haul) road to success

Haul roads are used by the world’s largest and heaviest trucks and vehicles to transport bulk materials from mining sites to processing plants and other facilities. Properly designed, these roads reduce maintenance costs, increase site safety, and have a significant effect on the clients’ bottom line.

How important are haul roads? Well, entire books have been written about their design, construction, and management. Experts such as Roger Thompson, who co-authored “Mining Haul Roads – Theory and Practice,” give workshops on the subject. In short, it’s an ever-evolving, highly specialized area of design that carries its own weight and then some.

When designing a haul road, every component is important, down to the smallest detail. For example, a compact, smooth road can decrease rolling resistance (RR) – the force that resists the motion of a vehicle – while increasing productivity. Ensuring that roads aren’t soft, and therefore prone to ruts or gullies, can:

• improve fuel consumption up to 1,000 liters per day
• improve vehicle speed on surface haul roads (a 1% reduction in RR can increase truck speed capability by 16%-to-25%)
• improve speed on ramps (a 1% reduction in RR can increase truck speed capability by 6% to 10%)

Additionally, keeping up with new technology – such as automated vehicles (AVs) – allows clients to plan for tomorrow’s innovations today. For example, the lane widths on a recent haul road project exceeded the standard dimensions to accommodate AVs that, while not in use yet, will be in the future. By acting like owners, Hatch was able to anticipate its clients’ needs, and design a future-ready road.

There are, of course, haul road components that remain constant regardless of the types of vehicles using them, including:

• ramps
• drainage
• elevation and slope
• paving material
• vehicles type and volume
• vehicular weight
• curves in the road
• signage
• width of the road

A well-planned and well-maintained haul road translates into greater productivity and prolongs the life of equipment (e.g., the cost of one tire on a CAT97 dump truck is $100,000 so reducing the wear and tear on a fleet adds up). Currently, truck haulage expenditures can account for up to 50 percent of surface mining operational costs. Those costs increase exponentially when a haul road is poorly designed and/or maintained. There have been instances where clients have wanted to replicate an old haul road by using the same inexpensive materials and approach to build a new one. Clients will sometimes request to ‘copy and paste’ an existing road pavement that’s been performing for a couple of years (possibly short of the design life). Their thinking is that the old road withstood the test of time so why not reproduce it? Considering all pavement inputs are highly variable based on use and location, it is prudent to ask the following key questions:

• How long has the older haul road paving been in service? Has this been compared with the design life of the proposed pavement?
• Are the vehicle types, payloads, and volume of traffic going to be the same on the new road as they were on the old?
• What was the existing ground bearing capacity or strength vs. the new site’s ground capacity?
• Can the same quality pavement material be sourced from site, or does it need to be imported?

Getting any of these questions wrong can result in over- or under-designed roads that require higher maintenance costs.

The “secret” to a successful haul road project is to provide honest answers to tough questions. At Hatch, we pride ourselves on being unconditionally honest, so give us a call before undertaking your next haul road project. Our clients benefit from years of expertise and experience that results in a strong partnership and paves the way for a successful project – over the long haul.