Every open-pit mine and quarry has the same basic problem: material is at the bottom, and the plant, stockpile or loadout is at the top. Trucks on haul roads solve it at a cost in fuel, tires and road maintenance. Conveyors are cheaper per tonne, but a standard conveyor climbs slowly, and in a pit or on a hillside site there often isn’t room for the long, gentle ramp it needs.
That is where steep-angle conveying comes in. This article looks at the question from the site layout side first, then explains when a corrugated sidewall belt is the right tool and when it isn’t.
Start with the terrain, not the belt
Conveyor routes in mines are usually planned on a terrain model: a digital elevation model (DEM), drone survey or laser scan of the pit, benches and surrounding ground. Slope analysis on that model shows where a conveyor can run and how much horizontal space each route would take. In an active pit, that space competes with haul roads, benches that will be mined later, drainage and setback zones.
The key number is the inclination the conveyor can climb. A conventional troughed belt carrying bulk ore or aggregate is typically limited to around 15–18° before material starts rolling back. A chevron (patterned) belt adds a few degrees, usually reaching 25–30°. A corrugated sidewall belt, with flexible side walls and cross cleats forming pockets, can run at 30° up to fully vertical.
The difference in footprint is large. To lift material 30 m:
| Conveyor type | Typical max. angle | Belt length (approx.) | Horizontal footprint (approx.) |
| Conventional troughed belt | 16° | 109 m | 105 m |
| Chevron belt | 28° | 64 m | 56 m |
| Corrugated sidewall belt | 60° | 35 m | 17 m |
| Corrugated sidewall belt | 90° | 30 m | 0 m (vertical) |
Values are geometric, calculated from lift height and angle. Real installations add loading and discharge sections, but the proportions hold. On a GIS layer, a 105 m ramp and a 17 m incline are two very different corridors, and the shorter one may be the only one that fits between benches or inside a crushing plant’s existing boundary.
Fewer transfer points, fewer problems
When a conventional conveyor can’t fit in a straight line, designers break the route into several flights with transfer chutes between them. Each transfer point is a source of spillage, dust, wear and blockages, and each one needs a drive, structure and maintenance access. A sidewall belt can often replace several flights with a single conveyor that runs horizontal, bends up the slope and runs horizontal again at the top, in an L or S profile. For underground-to-surface transfers, pit-floor crushers feeding a plant on the rim, or quarries on hillsides, that simplification is often the main reason to choose one.
Choosing sidewall height and cleat spacing
A corrugated sidewall conveyor belt is specified by three things beyond the base belt itself: sidewall height, cleat type and cleat spacing. Typical rules of thumb:
- Sidewall height sets the pocket depth and therefore capacity. Common heights range from about 60 mm to 300 mm or more. Higher walls carry more per meter but need larger pulleys and more headroom.
- Cleat type depends on the angle. T-shaped cleats suit moderate inclines; TC or TCS cleats, with a curved or reinforced profile, hold material better at 60° and above.
- Cleat spacing is chosen from the lump size and angle. Steeper angles and finer material need closer spacing, so each pocket carries a full load without spilling over the cleat.
- Base belt needs transverse rigidity so it doesn’t sag between the side walls. A cross-rigid carcass, usually EP fabric with a stiff transverse layer, is standard.
The easiest way to get these right is to start from the required capacity in t/h, the lift height and the largest lump size, and let the manufacturer size the pockets from there.
Where sidewall belts fit, and where they don’t
Good fits: crushed ore and aggregate after primary crushing, sand, gravel, coal, limestone and similar free-flowing material; tight sites where footprint matters more than tonnage; vertical lifts out of pits or shafts; and loading ships or bins where a conventional conveyor would need a long boom.
Poor fits: run-of-mine rock with very large lumps before crushing; very sticky, wet clay that packs into the pockets and is hard to discharge; and long overland routes on flat ground, where a conventional belt carries more per meter of width at lower cost. At high tonnage and long distance, a sidewall belt is rarely the economical choice.
In other words, a sidewall belt solves an elevation problem, not a distance problem. Mine planners who use it for the steep section and conventional belts for the rest usually get the best of both. More on how different belt types are used across a mine can be found in this overview of mining conveyor belts.
Conclusion
Steep-angle conveying is a layout decision before it is an equipment decision. When the terrain model shows that a conventional ramp would cross future benches, need several transfer points or simply doesn’t fit, a corrugated sidewall belt can lift the same material in a fraction of the space. Suppliers such as Hongkun Belting, a Qingdao manufacturer of heavy-duty rubber belts, build sidewall belts to the customer’s lift height, angle and capacity. The planning work, though, starts on the map.