The ability of a haul truck to carry a payload is not the only factor which determines efficient hauling operation underground. Underground haul trucks must function inside narrow spatial constraints determined by the geometry of excavations, articulation of equipment, and dynamic movement depending on the speed. The process of choosing equipment should be based on an engineering approach which combines static dimensions of vehicles, cornering, and dynamic vehicle movement in relation to mine drifts (Stantec, 2008; Huayi Heavy, 2026).
The size specifications of subterranean drifts provide the permissible limit of space for haulage trucks. The engineers must calculate the overall width and height of the machinery in relation to the dimensions of the drift, considering the minimum buffer clearance above the operator cabin and machinery body. Clearance height also limits body dumping height, and therefore ejector boxes are required technical solutions in cases of low overhead clearances. Lateral clearance requirements are legally required for pedestrian and utility safety. For instance, Saskatchewan Mines Regulations state that there should be a minimum lateral clearance of 1.5 meters from the drift walls or obstructions, or 2.0 meters where pedestrians move unless safety stations are created every 30 meters (Government of Saskatchewan, 2018). Width formulas include overall width, tire width, and speed of operation.
A center-steering feature allows underground haulage trucks to travel through tight curves underground using a frame angle that is normally between 42.5 and 44 degrees. The travel through the ninety-degree curve will need the measurement of both inner and outer clearance of the path. For example, the Sandvik TH430 has an inner turn radius of 4,544 millimeters and minimum tunnel width of 5,349 millimeters (Sandvik, 2026), while the Caterpillar AD30 needs an outer clearance of 8,571 millimeters (Caterpillar, 2022). Length of the vehicle, wheelbase, and front geometry will determine which part of the truck, nose or tail gate, will clip the wall while making a turn. Superelevation will overcome the centrifugal force to avoid any wheel slip and tire wear (E3S Web of Conferences, 2026).
Static clearance buffers do not consider the dynamics of the motion of vehicles traveling at a very high speed. Motion of the vehicles through the floors causes transverse motion or rolling as well as tilting due to rigid suspension systems. Mathematical modeling reveals that the lateral displacement is equal to the multiplication of the height of the machine by the tangents of the angular displacement. Lateral displacement increases continuously with increasing travel speeds ranging from 0.5 to 5.5 meters per second, significantly reducing the safety margin on the sides of the walls. Construction of pavements on the roadway using high-strength concrete wheel tracks in trenches in the floor reduces oscillations by 12-15% while allowing increased speeds of 25-30% (E3S Web of Conferences, 2026).
The choice of underground haul trucks needs a thorough spatial analysis that goes well beyond the mere ability of hauling a load. It is imperative for achieving balance between the geometry of the static clearance envelopes, dynamics of turning movements, and dynamic movement analysis. The mine planning team has to perform joint spatial analysis in feasibility studies.
References
Caterpillar Inc. (2022). Technical Specifications for AD30 Underground Mining Truck (AEXQ3472). Peoria, IL: Caterpillar Inc.
E3S Web of Conferences. (2026). Haul-Dump Machines in Actual Underground Mining Conditions. CEUMR 2026, Vol. 739, 03002.
Government of Saskatchewan. (2018). The Mines Regulations, 2018. Chapter S-15.1 Reg 8. Regina, SK: Queen’s Printer.
Huayi Heavy Industry. (2026). Underground Dump Truck Selection Guide: Payload, Turning Radius and Profile in Underground Dump Truck Selection. Huayi Heavy Knowledge Hub.
Komatsu Ltd. (2026). HX30 Underground Mining Truck Specifications and Product Guide. Komatsu Mining Corp.
Sandvik Mining. (2026). Toro™ TH430 Underground Truck Technical Specification. Sandvik Mining and Rock Technology.
Stantec Consulting Ltd. (2008). Hard Rock Miner’s Handbook (5th ed.). Developed by Jack de la Vergne. Edmonton, AB: Stantec.
