In open-pit mining and quarrying, loading and haulage is often one of the largest items in total production cost. Getting blasted material to the crushing plant requires a significant budget covering fuel, tyres, maintenance, operators and road maintenance for loaders and trucks. As the pit deepens and distances grow, this cost rises further.
In this guide we cover loading equipment selection, truck matching, cycle time analysis, the effect of road maintenance, tyre costs, in-pit crushing and conveying alternatives, and fleet management.
Loading Equipment Selection
| Equipment | Advantage | Disadvantage | Suitable Use |
|---|---|---|---|
| Tracked excavator (backhoe) | High breakout force, efficient in hard and coarse material, can sit above the truck | Low mobility | Blasted rock piles, fixed loading points |
| Front shovel | High capacity, efficient on tall piles | Large investment | Large mines |
| Wheel loader | Fast moving, multi-purpose (stockpiles, loading, clean-up) | Tyre wear in hard, coarse material | Stockyards, crusher feeding, flexible operations |
| Direct feeding (loader to crusher) | No trucks needed | Limited to short distances | Piles very close to the crusher, mobile crushers |
Bucket selection also affects productivity: a bucket volume, wear liners and tooth system suited to the material’s density and fragmentation determine fill factor and bucket life. Regular checks of bucket teeth also stop broken teeth entering the crusher (magnetic separator and metal detector guide).
Truck Matching
The match between loader and truck determines fleet productivity. The general principle is that a truck should be filled by the loader in a reasonable number of passes (usually 3–5).
- A truck filled in too few passes: the loader may be oversized; the truck body is damaged by impact.
- A truck filled in too many passes: loading time lengthens and trucks queue.
- Number of trucks: set so that the loader works without waiting but trucks do not form long queues.
- Crusher hopper: truck capacity must suit the crusher hopper volume; otherwise trucks wait to tip.
Cycle Time Analysis
A truck cycle consists of the following components:
| Component | Improvement Opportunity |
|---|---|
| Manoeuvring and waiting at the loading point | Loading area layout, double-sided loading |
| Loading time | Bucket–truck match, operator skill, fragmentation quality |
| Loaded haul | Road gradient, surface quality, distance |
| Waiting and tipping at the dump point | Crusher capacity, hopper volume, bridging at the crusher |
| Empty return | Road quality, traffic arrangement |
Measuring the cycle time and breaking it into its components shows where the bottleneck is. For example, if bridging is frequent at the crusher, the problem may lie not in the loading fleet but in blast quality (drill and blast guide).
Road Maintenance and Tyre Costs
The quality of haul roads is a hidden driver of haulage cost:
- Rolling resistance: Damaged, muddy and loose-surfaced roads increase rolling resistance; fuel consumption rises and speeds fall.
- Tyre life: Sharp rocks, potholes and tight bends cause tyre cuts and premature wear. Large truck tyres are expensive and can have long lead times.
- Road maintenance: Regular grading, clearing spilled rock, drainage and watering (dust control) should be carried out.
- Ramp design: Gradient and bend radius must suit safe and efficient truck operation (quarry planning).
Cost per Tonne-km
A practical way to compare haulage costs is the cost per tonne-kilometre. It is found by dividing the total of fuel, tyre, maintenance, depreciation, operator and road maintenance costs by the product of tonnes hauled and distance. As distance increases, the total cost of truck haulage rises linearly, which makes alternative haulage methods attractive beyond a certain distance.
In-Pit Crushing and Conveying (IPCC)
In-pit crushing and conveying is the approach of crushing material inside the pit and carrying it to the plant by belt conveyor.
| Approach | Description |
|---|---|
| Fully mobile | A mobile (tracked) crusher works next to the loader and discharges directly onto a conveyor; no trucks needed |
| Semi-mobile | The crusher sits in a modular station relocated at intervals; trucks haul short distances |
| Fixed in-pit crusher | The crusher is fixed in the pit; a conveyor carries material to the plant |
Advantages: Lower operating cost (especially for long distances and high tonnages), lower fuel consumption and emissions, fewer trucks and operators, less dust and traffic risk.
Disadvantages: High investment, less flexibility in the mine plan, the need to move and extend the conveyor line, and the whole line stopping if the primary crusher fails.
For conveying see our belt conveyor guide, for mobile crusher selection our mobile or fixed guide, and for maintenance our mobile crusher maintenance guide.
Fuel, Emissions and Electrification
Diesel consumption accounts for a significant share of haulage cost and carbon footprint. To reduce fuel consumption:
- Reduce idling time,
- Train operators in efficient driving,
- Improve road quality,
- Select equipment of appropriate power,
- Where suitable, consider electric equipment, conveyors and electric mobile crushers.
For sustainability approaches see our sustainability in mining guide.
Fleet Management and Tracking Systems
- GPS-based fleet tracking: Truck position, speed, waiting and cycle times are monitored.
- Payload monitoring: Excavator or truck weighing systems prevent overloading and underloading.
- Dispatch systems: In large mines, trucks are assigned to loaders dynamically.
- Maintenance tracking: Maintenance plans based on operating hours and failure records.
- Safety systems: Collision avoidance, fatigue detection, blind-spot cameras (occupational safety guide).
Field Example
Suppose that at a limestone quarry trucks frequently wait at the crusher and the fleet runs below its capacity. Cycle time analysis shows that most of the waiting comes from bridging by large blocks in the crusher hopper. When blast design is improved and a hydraulic rock breaker is installed at the crusher, truck waiting times fall and the same production can be achieved with fewer trucks. This example shows that haulage efficiency depends not only on the number of trucks but on every link in the chain.
Frequently Asked Questions
Excavator or wheel loader?
An excavator is generally better suited to hard, coarse, blasted rock piles; a wheel loader to flexible work, stockyards and short-distance tasks.
How many trucks are needed?
It is calculated from cycle time, truck capacity and target production; the aim is for the loader not to wait and trucks not to queue.
When does conveyor haulage become economical?
It generally becomes economical with high, continuous tonnage, long haul distances and a long pit life; it should be assessed with a feasibility study.
Is road maintenance really that important?
Yes. Road quality directly affects fuel consumption, tyre life, speeds and safety.
Spare Parts Planning Along the Haulage Chain
Each link in the loading and haulage chain has its own wear and maintenance needs. When one link stops, the others have to wait as well.
| Link | Critical Parts | Note |
|---|---|---|
| Loader / excavator | Bucket teeth and adapters, bucket liners, side cutters | Broken teeth must not enter the crusher |
| Truck | Tyres, body liners, brake parts | Road quality determines life |
| Crusher feed hopper | Hopper liners, grizzly | Truck tipping impact (hopper spare parts) |
| Feeder | Grizzly bars, springs, liners | (Feeder spare parts) |
| Primary crusher | Jaw plates, cheek plates, toggle plate | (Jaw crusher spare parts) |
| Pit conveyors | Belt, impact idlers, scrapers, pulleys, gearboxes | (Belt conveyor spare parts) |
For belt and idler selection on primary crusher product conveyors, see our conveyor belt and conveyor idlers guides, and for loading point design our skirt rubber and loading chute guide.
Cycle Time Measurement Form
| Component | Measured Time | Note |
|---|---|---|
| Arrival and manoeuvring at the loading point | min | Is there a queue? |
| Loading | min | Number of passes |
| Loaded haul | min | Distance, gradient |
| Waiting to tip and tipping | min | Crusher status |
| Empty return | min | — |
| Total cycle | min | Trips per hour |
Glossary
- Cycle time: The total time for a truck to load, haul, tip and return.
- Fill factor: The ratio of a bucket’s actual filled volume to its nominal volume.
- Cost per tonne-km: The cost of hauling one tonne one kilometre.
- IPCC: In-pit crushing and conveying.
- Rolling resistance: The road surface’s resistance to vehicle movement.
- Dispatch system: Software that assigns trucks to loaders dynamically.
More Questions
How can truck tyre life be extended?
Through road maintenance, correct tyre pressures, avoiding overloading, clearing spilled rock and operator training.
Is conveyor haulage possible on sloping ground?
Yes. Belt conveyors can carry material up to certain inclines; special belt solutions are used for steeper inclines. A backstop is critical on inclined conveyors.
When is a mobile primary crusher preferred?
If the face is constantly advancing and the haul distance is growing, a combination of mobile crusher and conveyor can reduce the need for trucks.
CSP Mühendislik Support
CSP Mühendislik provides design, fabrication and supply support for in-pit crushing stations, overland and stacking conveyors, feed hoppers and conveyor spare parts. See our belt conveyor spare parts page for conveyor parts and our hopper spare parts page for hoppers, and use our crushing and screening plant set-up guide for plant planning.
