Loading And Transport: Complete Technical Guide

The loading and the transport is the invisible giant of the cement plant economics: the stone is moved more times than it is machined: from the blasted face to the loader, from the loader to the truck, from the truck to the crusher, from the crusher through the belt galleries to the stockpile, and again from the stockpile to the raw mill: each of these moves carries a cost per ton, and the moves repeat for the 25 years of the plant life: the transport is the tax that the plant pays on every single ton it handles, forever.

The discipline covers the equipment families and the flow sheet: the shovels and the loaders, the haul trucks, the crusher feeding, the belt conveyors with the transfer towers and the chutes, the rail and the barge alternatives, the apron feeders, the storage reclaims, and the dust, the safety and the maintenance of it all: the file of the Complete Cement Technical Package (931 files: the bulk handling handbooks, the conveyor selection spreadsheets, the fleet management courses: $249.99 one-time: instant download via PayPal) documents each with the tables, the formulas and the worked examples, and this article follows its skeleton end to end.

The reader who finishes this page can: compute a haul cycle, size a belt, judge a fleet bid, weigh the conveyor vs the truck decision, and plan the loading of the winter; the article is the class, the file is the text of the class, and the Excel tools of the package are the exercises.

1. The Loading Equipment: From the Face to the Truck

The blasted rock is lifted by the loading machines: the choice depends on the tonnage and the stone size:

• The hydraulic excavators (the backhoe and the face shovel): the backhoe digs below the bench (the bulk), the face shovel loads above: the buckets of 4-12 m3 for the 3000-8000 t/d quarries: the cycle 25-40 s: the penetration in the blasted rock is unmatched;
• The wheel loaders: the flexible companions: the bucket 5-9 m3 on the 45-90 t machines: load the trucks, clean the face, feed the crushers, build the stockpiles: not the primary excavation machine of the deep benches;
• The hydraulic breakers cannot load: they handle the oversize: the breaker on the excavator clears the secondary breakage at the face: the reduction of the oversize is the first stage that avoids the crusher jam;
• The rope shovels: the massive electric excavators of the giant quarries (50 m3 and above): the big mines of the limestone use them when the face height exceeds 15 m and the power is cheap;
• The dozers: the rip and the push of the soft material, the assistance to the loaders, the bench housekeeping: never the primary loaders of the hard rock;

The loading rate is the product: bucket fill factor x the cycle rate: the fill factor of the blasted limestone 0.85-0.95: the cycle of the loader 0.4-0.6 min: a 7 m3 bucket loads 700 t/h of the loose stone: the file’s loader selection Excel sizes the machine from the quarry production rate combined with the number of the trucks.

2. The Haul Trucks: The Cycle Time and the Fleet Math

The haul trucks connect the face to the crusher, and their math is the discipline of the mine:

• The truck classes: the rigid dump (30-100 t) for the short medium hauls: the articulates (25-40 t and the 6-wheel all drive) for the rough and the soft roads: the off-road rigid 200-400 t (the mega of the copper-style) for the distance hauls of the huge pits: the cement quarries mostly live in the 45-100 t class;
• The cycle time: the load time (the 5-8 bucket passes, 3-5 min), the travel loaded at the 8-15% grade, the respective speed 15-30 km/h, the dumping 1-2 min, the travel empty 30-45 km/h, the queues: the cycle formula of the file: T_cycle = T_load + T_loaded + T_dump + T_empty;
• The fleet count: the trucks = the crusher demand x the cycle / the truck payload: the availability 85-92% and the utilization factored: the fleet of the 3000 t/d quarry: 4-6 trucks of the 55 t;
• The Rimpull and the grade: the engine power vs the rolling and the grade resistance: on the 10% rise the 55 t truck carries about half the payload at the speed: the road design (the maximum 8-10% sustained grade) governs the fleet productivity: the calculator of the bounce;
• The fuel and the tires: the hauling is 60-75% of the quarry energy bill: the diesel per ton increases linearly with the distance: the tire cost 8-15% of the hauling: the smooth graded roads extend the lifetimes 40%: the road housekeeping is the invisible profit center;

The transport decision between the trucks and the conveyor is the classical comparison of the file: the trucks are the flexible master; the belt is the efficient slave: the crossover distance for the limestone is typically the 3-7 km depending on the tonnage: the belt capex recovers against the fuel and the tires at the high and the continuous rates: the file’s decision table does the math par line.

3. The Crusher Feed: The Apron, the Sizer and the Rock Breaker Line

The haul trucks dump into the primary crushing: the feeding discipline decides the crusher health:

• The feed hopper: the 150-300 m3 pocket below the dump ramp: the trucks back to the edge, the stone falls into the hard-lining hopper: the level ensured so the falling stones don’t slam the steel floor directly (the “living floor” cushion);
• The apron feeder: the armored flights move the stone at the controlled rate: variable speed 0-1.5 m/s, the depths 1-2.5 m, the capacity 500-3000 t/h: the uniform supply is the first secret of the continuous crusher operation;
• The grizzly: the bar screen at the hopper mouth: the fines (minus 100-150 mm) short-circuit the primary crusher: the bypass saves the energy and the wear: the fines belt joins the circuit below the crusher;
• The crusher types in the line: the jaw (the tough stone, the 300-1500 t/h, the setting 100-250 mm), the gyratory (the highest rates, the 600-6000 t/h, the same setting family), the impactor (the softer stone, cheap, the high reduction, the dust): the file’s crusher chapter compares;
• The metal detection: the tramp iron (the drill bits, the shovel teeth) armored: the belt magnets and the metal detectors upstream of the crusher: one drill bit = one jaws replacement: the detector is cheap;

The crusher station is also the dust problem of the site: the dumping bay with the suppression spray and the vent hood: the file’s emission tables prescribe the pickup covers and the filters: the neighbours that accept the quarry without the noise, the blast and the dust are the neighbors that the quarry keeps for 25 years.

4. The Belt Conveyors: The Arteries of the Material Flow

The belt conveyor is the most repeated machine of the cement plant: its design follows the standard rules:

Parameter	Typical range	Notes
Belt width	800 – 2000 mm	3-4 x the maximum lump
Belt speed	2 – 4.5 m/s	Fines/dust limit; the faster the more the dust
Capacity	300 – 5000 t/h	The cross-section x the speed x the density x k
Roller spacing	1 – 1.6 m (carry)	Tension, the sag
Transfer chutes	velocity control	the chute evens the flow and cuts the dust
Angle of the slope	max 15-18° (raise)	The +90° the pipe conveyor for the steep

The belt sizing formula of the standards (the CEMA method): the cross-sectional load from the surcharge angle (20-30 degrees for the crushed limestone); the file provides the belt selection Excel where the engineer enters the tonnage, the lump size, the length and the lift, and reads the belt width, the powers and the drive:

• The drive: the head (or the dual) pulley with the wrap angle and the snub: the power = the lift power + the friction: the кВт per 100 m at the 1000 t/h: 30-60 kW on the flat, more on the grades:
• The take-up: the gravity take-up maintains the tension: the frame and the counter weight: the belt stretch of the thermal changes absorbed;
• The idlers: the 35-45 degree troughing, the rubber cushion at the loading zone: the idler life 30-80 thickness for the 40 t/h belt as the abrasion governs;
• The maintenance of the gods: skew and the alignment: the training idlers steer the belt: the misalignment kills the belt edges: the weekly patrol and the yearly laser of the frame: the file’s PM tables;

5. The Material with the Reclaim: The Second Transport Leg

From the stockpile and the silo to the mill, the flow is metered and measured: the third leg of the transport:

• The belt scale: the continuous nuclear or the load cell flow measurement on the reclaim belt: the kg per second to the square: the dosage of the bins uses the flow signal with the ±1-2% accuracy: the calibration the chain check weekly;
• The weigh feeders: the loss-in-weight (the whole bunker on the load cells) and the belt-type (the variable gate) for the four-five separate proportioning: the receptivity of the loop is the seconds, so the mill sees the constants;
• The screw conveyors: the short transfers of the fine meal (the 30-100 t/h, the 30 m max) inside the silos and the mills: the energy moderate: the fines the dust tight;
• The bucket elevators: the vertical transfer the classic: the 50-500 t/h with the belts and the chains: the mill feed and the elevate the fines: the head and foot the maintenance:
• The airslides: the inclined air-supported troughs for the fine dry materials (the raw meal connectivity), the 300-1000 t/h, the slope 4-6 degrees, the air rate governed by the fluidization: the perfect interface between the mills and the silo tiles;

The transport system of the raw materials is the “equation of the plant”: each leg it metered, each leg it controlled: the file of the equipment covers the metering and the tracking (the ERP of the material) with the flow sheets: the plant that runs the raw material movement on the discipline of the balances knows its stock, its cost and its production truth.

6. The Rail and the Barge: The Long-Distance Alternatives

When the quarry is far from the plant, the transport leaves the truck learning and goes the rail or the barge:

• The rail: the hopper wagons the 50-100 t, the unit trains of the 100-200 wagons: the cost per ton-km 30-50% below the truck on the long distances: the loading station with the sluice, the unloading with the wagon tippler or the bottom doors: the line of the plant spur: the freight cars roundtrip 2000-4000 t/d easily;
• The sea and the river: the bulkers and the barges: the limestone imported across the water: the 20,000-60,000 t voyages: the handling with the port cranes and the belt unloaders: the moisture and the demurrage are the risks: the season of the river also;
• The overland conveyor: the 5-26 km of the single-flight early belt: the cliffs, the valleys scaled with the vertical towers: the “conveyor economy” (the cost per t flat with the length up to some km) wins the medium distances;
• The hybrid: the truck to the station, the rail to the plant: the silos both ends: the double handling but the flexibility: the typical the Egyptian and the Indian models;
• The cost comparison: the file’s transport matrix: the USD per tonne for the 50 km: truck 4.2, rail 2.1, barge 1.3 (the figures indicative of the file’s price year) – the sensitivity of the distance, the volumes, the fuel:

The choice of the mode is the decision with the decade of the fuel price: the file’s economics include the fuel price scenarios (the 10-year curve) and the speedy dollar per km of each; the reader can run the model of his own numbers: the package is complete with the models.

7. The Dust, the Safety and the Environment of the Transport

The transport of the raw materials is a source of the dust, the noise and the risk: the file’s chapter 8 enforces the practice:

• The dust: the suppression systems at the loading, the transfer and the discharge points: the bag filters at the towers: the water spraying on the haul roads: the fence and the receptor monitoring: the TSP of the quarry boundary the limits of the local standards;
• The truck and the haul safety: the restricted speeds (the 20-25 km/h in the site), the rules of the right of the way by the load, the collision avoidance and the mirrors, the dedicated corridors from the pedestrian: the driver fatigue: the standards;
• The conveyor safety: the lockout-tagout at the start, the pull cords, the emergency stopping, the guards of the rollers: the fires in the long his (the detection with the infrared and the water curtains for the coal):
• The confined spaces: the chutes, the hoppers, the silo the entries: the permit system, the gas tests, the trained rescue teams: the accidents of the industry are mostly here: the training records the file:
• The housekeeping: the spillage is the poison of the transport: the swept collection points, the recycling of the fines: the audits of the monthly:

The safety culture of the transport is like the chain: the weakest link: the file’s checklists of the transport audit traverse the yard, the face and the conveyor galleries; the plants with the disciplined loops herd the incidents and the quality of the delivery: the safety is also the economics: the downtime of an injury costs the tonnage of the whole day.

8. The Worked Example: The Quarry Fleet of the 5000 t/d Plant

The worked case of the file, so the reader has the pattern of his own:

Given: a 5000 t/d clinker plant needs 8000 t/d of the raw + waste: the haul distance from the active bench to the crusher: 2.4 km loaded, the 8% average grade: the excavator 7 m3, the trucks 60 t (55 t payload): the crusher feed required: 1000 t/h:

• The truck cycle: the load 5 x 40 s = 3.3 min, the loaded travel 4.2 km/h 22 = 5.7 min (figure eh), the dump 1.2 min, the empty return 6.2 min, the queue slack 1 min = 17.4 min round: 55 t / 17.4 x 60 = 190 t/h per truck;
• The fleet: 1000/190 = 5.3 -> 6 trucks with the 87% of the mine availability: with the minor road the fleet can do 6.2; the 6 trucks deliver 1100+ t/h max: the crusher 1000 t/h: ok;
• The pit efficiency: the dumper arrival matches the excavator cycle: 6 trucks x 55 t = a truck every 19.8 min vs the 7 m3 load at 5.5 buckets in 3.7 min: the loading stands 30% of the time: the pit manager adds the 7th dumper when the distance rises to 3.7 km;
• The annual fuel: the diesel line: 8000 t/d x the distance x the specific: the file’s fuel table sums 2.1€ M liters at the price year: the single largest variable of the quarry;
• The validation: the file’s fleet calculator returns the same with the allowances: the reader can test the sensitivity: the new truck price, the fuel, the tire: the verdict: keep the trucks, the belt pays at the 5->6 km

The patterns: the fleet doubles with the 1% of the cycle, the truck count is the integer: the oversizing is costly (the idle capital), the undersizing starves the crusher: the file’s table of the mining trucks provides the recommended loads by the bench height and the road class: the worked sheet is the sixth sheet of the file’s transport workbook.

9. The Maintenance of the Transport: The Ships of the Iron

The moved masses wear their machines: the maintenance regimes of the transport family:

• The truck fleet: the hourly inspections, the oil at the makers (250-500 h), the tyres daily press, the brake tests weekly: the scheduled off-line for the 2,000 h: the file’s schedules table by the make:
• The loading machinery: the bucket teeth the replacement cycles, the pins and the bushes the monthly greases, the undercarriage the track adjust: the excavator availability 92-95% with the regime:
• The conveyor: the rollers the sample replacement, the combs…, the belt the joins (the vulcanization 4-6 hours), the take-up the season checks: the belts give 5-15 years by the ampere:
• The crusher: the liners (the jaws 2-6 months by the stone, the gyrbore 6-12), the toggles the setting checks, the lubrication the 24-turn: the wear progression in the CMMS of the file:
• The storage: the reclaimers and the stackers: the track alignment, the scraping the armour: the winter the grease

The maintenance database (the CMMS of the file) tracks the cost per hour, the MTBF and the MTTR per the asset: the plants at the 88-94% availability survive; the ones below bleed: the file’s maintenance KPI dashboards give the targets: the reader who runs the dashboard gets the machine stories of the quarry in one screen.

10. The Frequently Asked Questions

Why don’t they just use the belt from the quarry?

The belt is the energy master, but the quarry moves: the face advances, the benches deepen and the crusher is the fixed: the belt from the moving face requires the mobile or the extensible systems which are feasible above the 5000 t/d: the trucks remain the flexible spine of the face – the belt cleans up from the crusher toward the plant (the fixed paths) and the trucks feed the head; this split is the balance of the file.

The transport and the loading to reduce what?

Reduce the number of the handlings: every movement is a cost: the flowsheet aims for the 3-4 touches from the face to the raw mill: the crushed stone to the pile (1), the pile to the mill (2), plus the corrections: the fewer the touches, the lower the cost and the dust: the file’s flow sheet analysis counts the touches per the plant.

Is the rail better than the truck?

At the high and the constant volumes over the long distance: yes: the rail at the 10+ km at the 2000 t/d beats the truck on the unit cost by 30-50%: under the 3-5 km the truck is hard to beat; the exact cross-over of the file’s calculator: distance x tonnage on the chart decides in the minute.

The transport of the alternative raw materials is the same?

Similar with the accents: the fly ash is pneumatically transferred (the tankers, the 0.2-0.4 bar lines), the slag travels the truck or the rail, the liquids (the by-pass or the sludge) by the tanker: the file’s chapter of the alternative materials covers the specialized receivers: the loading the vessels, the tankers etc.

The most common transport breakdown?

The belt conveyor stoppage has the highest impact (the whole chain stops): the causes: the jam at the transfer to a certain chute, the bearing failure, the belt damage by the foreign matter: the prevention: the chute design, the roll protectors of the tracking, the metal detectors and the housekeeping: the mood in the file’s failure mode analysis.

11. The Conclusion

The loading and the transport of the raw materials is the whipped league of the cement plant: no kiln module, but the whole plant runs at its rhythm: the trucks, the belts and the feeders move the stone at the cost that accumulates into the 1-3% of the cement selling price: the equation of the fleet, the sizing of the belt, the station of the rail and the disciplines of the dust and the maintenance are the set of the work: this article is the summary of the file, and the file is the desk of the transport engineer: the numbers are the language, the Excel the calculator, and the package the library.

The Complete Cement Technical Package (931 files: the transport, the storage, the crusher and the conveyor sections, the entire Excel models and the training: USD 249.99 one-time: the PayPal instant: the button below) delivers the complete transport chapter with the tables, the fleet workbook and this text: the click is the last transport cost you spend on the knowledge: the rest is the tonnage like any gallon of the diesel:

The Transport Planning in the Quarry and the Plant

The transport of the raw material covers the three legs of the material flow: the haul in the quarry, the overland conveyance, and the internal handling of the plant: each leg has its planning parameters:

• The quarry haul: the truck cycle (load, haul, dump, return), the cycle time versus the bench height and the road grades, the number of trucks matching the loader capacity: the rule of the mining: the loader waits never, the truck waits occasionally, the stone flows;
• The overland conveyors: the belt speeds and capacities (t/h at the given belt width), the transfer points and the chute designs, the spillage and the cleaning of the returns: the conveyor legs of the quarry link the crusher to the stockpile;
• The internal handling: the reclaim feeders and the tunnels, the belt scales for the dosage, the diverters at the crossroads: the internal transport is the first step of the proportioning control of the plant;
• The transport economy: the cost per ton-kilometer of each mode (truck, belt, rail), the energy per ton, the maintenance of the fleet and the conveyor components: the transport cost share of the raw material delivered to the mill;

The transport planning of the file closes with the key principle: the raw material flow must be continuous and measured: the continuous belt with the scale gives the plant the real feed while the truck transport gives the flexibility of the peak: the balance between the two is the economic question the file answers with the worked examples of the quarry studies.

The Weight Control and the Material Balance of Transport

The transport of the quarry material is also an accounting problem: the plant must know exactly the tons moved and delivered:

• The weighing stations: the truck weighbridge at the quarry exit and the plant entry, the belt scales of the conveyors, the tare and the gross records per vehicle: the double weighing catches the losses and the misreports of the haul;
• The reconciliation: the monthly reconciliation of the blasted tons, the hauled tons, the crusher feed, the stockpile change: the differences are the losses of the transport: the spillage, the rain washes, the sampling errors: the file gives the reconciliation format;
• The equipment records: the hours and the fuel per truck, the downtime per machine class, the utilization of the fleet: the transport report becomes the input of the maintenance plan of the mobile equipment;
• The shift plan: the daily tonnage target of the quarry versus the trucks dispatched, the waiting queue analysis at the loader, the utilization of the working faces: the planning board of the next shift drawn from the data of the previous one;

The weighing and the reconciliation are the discipline that keeps the quarry honest: without the weights no cost, and without the costs no decision on the transport modes: the file instructs the reader in the transport accounting so that the loading and the transport are not only a mechanical flow but a measurable business of the plant.

The transport meets the plant disciplines at the crusher feed: the haul trucks tip into the hopper, the apron feeder pulls the load to the crusher, and the transport cycle ends where the process begins: the file teaches the reader to observe this handover as the joint of two worlds: the mine schedule of the day and the mill feed of the day are the same tonnage expressed in two languages: the quarry master plans the daily stone in truck terms and the production manager reads it in mill-feed terms: the file’s conversion tables (truck loads to tons, tons to limestone percentage of the feeding) make the handover readable by both: the loading and the transport are the first material discipline of the plant: continuous, weighed, reconciled: the chapter closes with the recommendation to run the transport KPIs weekly, so the deviations of the road are seen before the deviations of the kiln.

This file is part of the Complete Cement Technical Package (931 files) available from cementequipment.org. Respective rights holders; library copy for the licensed single user.