Both of them have their advantages, Respectively Speaking, the belt conveyor is more time and effort saving so it saves the costs. however, it is inconvenient to move, which is the advantage of the trucks. ■

Originally Posted by mechanicaldesigner

What are the factors that determining the decision to use trucks or belt conveyors to transport the ore in a new mining.

What advantages and disadvantages have each of these options.

Thanks in advance for your help, if you can not answer at least I hope someone can recommend some books to read about it.

Please refer CEMA 5th/6th edition.

Rgds,

Narayanan Nalinakshan. ■

Originally Posted by mechanicaldesigner

What are the factors that determining the decision to use trucks or belt conveyors to transport the ore in a new mining.

What advantages and disadvantages have each of these options.

Thanks in advance for your help, if you can not answer at least I hope someone can recommend some books to read about it.

The problems with trucks no matter the tonnage class size

is that they are only fifty percent efficient.

Any 100 to four hundred plus ton payload truck will burn 64 gallons

PER HOUR loaded and EMPTY on the return trip per hour.

A basic 100 ton Caterpillar haul truck is $3,000,000 USD

not counting taxes, freight, replacement tires at $720,000

per year for spare parts, a qualified maintenance staff to

maintain them, the truck drivers require extensive driver

training for their operation, A system of haul roads must be

prepared and maintained for them to operate on, and they

will consume 560,000 gallons of diesel fuel per year if

operated 24 hours a day and seven days per week as is

the normal state of things in the Powder River Basin Coal Mines.

If a large enough number of haul trucks is employed an operation

center with radio communications to the truck fleet must also be

maintained as well to reduce the possibility of accidents and injuries from

truck impacts with excavators and crushing other service vehicles which

unfortunately still occurs every year.

Conveyors have a very high cost per foot

of installation in thousands of dollars

per foot and they require replacement

idlers belting, motors, pulleys, gearboxes,

chain drives, high or medium voltage electricity

to power them, emergency stop systems from

end to end and labor to maintain them as well.

as labor to install conveyor extensions.

A conveying system of any type requires

primary and secondary crushing systems

and or conveyor belt feeder/breakers to

load them as well. adding more to the

purchase cost and operational cost. ■

Land and weather are good grounds for eliminating either choice. The question should be "Do you want the stuff or not?" If the answer is yes then the economics is out of the window. You have to have it so be prepared to pay for it. Trucks need good dry ground to travel and plenty of it. Conveyors also need an acceptable right of way and can only negotiate a route within set limits. Truck CAPEX is not so small andthe OPEX is higher than for conveyors, provided you don't slit a belt into 2.

Appreciate that the equipment cost for a long conveyor is dwarfed by the route/road preparation cost of either a conveyor or trucking option. Road maintenance is less for a conveyor.

In essence: do you see more trucks bogged down in wet or soft ground than you see snapped belts?

As bulk handling engineers "Summus semper in faeces est, sole deprofundum variat." Now feel quite free to read CEMA from back to front, upside down and inside out. You'll still have to make your own decision. ■

The study of many overland conveyor (OLC) vs. truck haulage reveal some basic and new facts:

1. Break even point for OLC is a transport circuit that must convey 2 million tons per annum over more than one kilometer or the total multiplier of tons and kilometers . This is further dependent on local fuel costs and terrain difficulty. Some countries subsidize their diesel fuel that artificially lowers the truck penalty - that is now changing.

2. Conveyors can often be routed in a more direct path than the road haulage thereby reducing the kilometer penalty. The path may include bridges over rivers, roads, railroads, etc.

3. Conveyors can negotiate rough terrain to 18 degrees or more making for shorter paths or that would require tunneling by trucks.

4. Conveyor are more efficient with fuel usage than trucks especially with the payload of an empty truck return haul

5. Conveyor designs have become more efficient with new rubber compounds and new design methods, that lower rolling energy by 50% or more than many suppliers of rubbers from 5 years ago. Trucks have not seen such improvements in rolling losses. A case in point is the Curragh 20 km single flight overland that transports 2500 t/h. It is light and fast (7.5 m/s). It is very light for the tons conveyed due to efficient use of sheet metal components for is idler and belt support and wind shielding. IN 2007, it was the fastest operating belt conveyor in Australia. Speed lowers the conveyor system width which is the most capital intensive parameter. Some have disparaged the design and been wrong in their assessment. It's 5 m carry side and 10 m return idler spacing is proven to be appropriate when the plant has been properly operated.

6. New research into more efficient belt conveyor operations is proving that further cost effective gains are possible compared to trucks and trains. More difficult terrain, stronger belts, lower belt strength as measured by the necessary Safety Factor, lower rolling resistance designs, and lower metal mass per km all point to ongoing improvements over truck and trains.

7. New conveyor configurations can be found with better trough shapes, pipe, and semi-pipe designs are now a reality where high lifts and sharp curvatures are required that add to belt conveyor transport efficiency.

8. Studies of +100 km conveyors does demonstrate the ability for long and efficient transport compared wih train haulage. Risk Analysis then becomes an important factor in the "what if" scenarios. ■

The ultimate measure is Total Cost of Ownership per Cost per Ton per Kilometer in Net Present Value terms. Trucks cannot achieve the efficiency when the transport route remains fixed for more than five years and has a transport index of 2 million tons per annum over one kilometer long. Modern transfer chutes eliminate belt wear, puncture risk, dust, and spillage, along with a reduced belt width. Thus, the modern conveyor does not need to carry undesirable belt conveyor cover stock to overcome poor transfer chute design and accelerated belt wear. ■

"There are other more successful means of bulk material handling than conveyors. Rail-Veyor Material Handling Systems - here are the differences:"

Rail-Veyor has been around for quite a while but I have not heard such unrealistic claims before.

Derailment is a big issue with any rail system. I can tell you this because my old company invented the flanged railway wheel and never concealed the fact that trains frequently ran adrift throughout the ages. So you will still need a fleet of trucks to drive along the roadway to reach and clear the disaster area. If there is already a road and trucks then what is the point of any conveyor.

Road access is necessary for all conveyors to be able to deliver a belt reel or clean up the occasional spillage. If a belt gives up the ghost midway along a viaduct there still has to be access for the pull plate and winch.

The civil engineering standpoint is often overlooked. Whether the road should be wide enough for 2-way traffic is debatable. The inescapable point is that the road would be wider by eliminating the conveyor and the far side access. We are in the province of mechanical versus civil engineering preferences, with electrical engineering standing by in a cannot lose situation. Civil engineering will always win whatever the actual reality. Owners just want minimum CAPEX to get approval; funds etc. Their OPEX is governed by the value of the product throughout the workable life of the plant and is therefore unknown. So it reduces to minimising CAPEX on the advice of civil engineering costs and machine merits are irrelevant. FEED Contractors (how I hate that word and all it implies) expect to progress to EPC and will not risk paying for expensive machinery, which they know little about, when they can make their money shifting muck around, which they do know a little about.

Local politics should also be examined. One country, between Oz and Thailand, recently stipulated that all plants must revert to a local nationally controlled stake holding within 10 years of start-up. Staring in the face of a knock down bargain sell off any potential plants will have to examine the replacement issues of any fixed equipment alongside the potential alternative drive through situation. In the light of such nuances and the alarming frequencies of statutory whims it is very surprising that Owners ever consider investment in overland conveying outside N. America and Oz. ■

Dear John,

Your arguments against belt conveyors is very debatable:

1. When a feasibility study is made for a bankable note the study must assess all manner of risks - there are usually many John Gately's at the client's table. The study must be able to defend against such criticisms. The client hires experts from many opportunistic sources - truck, rail, pipe and conveyor experts. Conveyors or other transport methods are not chosen by a gift-of-gab consultant.

2. We have many conveyors that do not need substantial roadways and in some cases the roads are gone after nature takes over.

3. You can see that many conveyors are now elevated and support a self-powered maintenance trolley or two - no roadways

4. I take it you have not made a “cost of ownership” difference between truck and conveyor over long distances? The numbers cannot support a truck over a few kilometers and a few million tons per year, saying nothing of difficult terrain.

5. Cost of ownership is still key, which includes all manner of risk and rewards - roads, bridges, structures, civils, personnel, cost of power, cost of repairs, special crews, weather, flexibility of adding trucks, ......

6. I read with amusement the claims that conveyors have unrealistic cost penalties. Rubbish. A conveyor system must be able to compete against the alternatives during the feasibility phase. Most large consulting firms have experts in each area of ore transport or know where the experts can be drawn from. Each such expert gives proper representation of all costing. Modern large overlands, when properly designed and fitted for mine duty give a good accounting of $$/ton/km especially when compared with trucks. Try making a truck pencil out for a mine that must transport ore over 5km at 2,000 t/h (12 million tons per year) for 20 year life. You can install a conveyor for the same or less capital vs. the truck fleet and maintenance shed. Now look at the operating cost. The truck will cost the owner more than triple in Total Cost of Ownership. Then there is the risk of strikes, lack of tires or inflated cost of diesel. ■

Penalizing the conveyor with ore size reduction, is also a fallacy. The rock is going to be crushed in any case in order to be processed. One can argue about crusher maintenance in remote areas. Still these facts are assessed during the feasibility phase. ■

Arguments for belt conveyors are more debatable.

"Conveyors or other transport methods are not chosen by a gift-of-gab consultant." Oh yes, they very often are!

"......do not need substantial roadways and in some cases the roads are gone after nature takes over." If a user cannot be bothered to look after his access roads I imagine his overall maintenance must be equally shoddy.

"...not made a “cost of ownership” difference ..." No need to: I just have to present the claimed costs to the Client. Contractors will say anything about costs. It is their way of guiding a client toward their own personal cleaners without having to prove their competence. It used to be called cooking the books.

".....the risk of strikes, lack of tires or inflated cost of diesel." Strikes can shut down the whole plant; tyre wear could cost less than a slit belt (or 2) and if the cost of diesel or LPG goes up it is a pound to a pinch of dung that electricity prices will go up accordingly....on a remote site. Besides many mines now have driverless haulage which rather lessens the significance of striking drivers and their wages.

For myself, the adage 'If you bought it: it came on a truck.' holds a lot of truth. Mine owners frequently have downstream processing plants and 'plant' often presumes conveying their own stuff inside as well as off site. So be it. There are plenty of trucks earning a decent living, however inefficiently. Conveyors are regularly seen as ideal for transport between fixed stations and so they are. I have never seen one of these shiftable, overburden stripping and mining conveyors in operation but I think their relocation might not be as easy as the vendors claim. Same for overland conveyors with or without access roads or bridges. Once the overland is built you have to be in for the long haul and, as I tried to say previously, that might not be as long a time as it was thought to be. ■

Originally Posted by mechanicaldesigner

What are the factors that determining the decision to use trucks or belt conveyors to transport the ore in a new mining.

What advantages and disadvantages have each of these options.

Thanks in advance for your help, if you can not answer at least I hope someone can recommend some books to read about it.

feedback Hola

¿podras compartir cmo y por qu razones/parmtetros has resuelto el dilema-camin-faja?

could you share how and based on which reasons you solved the truck-belt-dilema?

gracias, saludos

dak

T +1858 5644045

M +54911 53252311

E bulk.good.solutions@gmail.com ■

I quite appreciate this topic being resurrected.

Mineral processing plants produce a lot of waste which is usually pulp. In cases where hydraulic conveying is used for waste shouldn't is also be examined for carrying ore. I have argued against the folly of amazingly appointed Oil & Gas Contractors who proposed trucking waste uphill while also conveying ore downhill to the plant. That apart, hydraulic conveying deserves mention for economy & route flexibility. A comminution plant is usually necessary to provide a conveyable product to the plant. None is required for waste disposal.

Elsewhere in these replies it is suggested that the power supply for comminution near the mine is a disadvantage for belt conveying. If an energy balance is imperative the addtional comminution effort for hydraulic conveying is insignificant because the infractucture overhead is pretty much the same.

Finally, for now, you should commonise the transport. Sending empty equipment in opposite directions is ecocide.

I can't apologise for turning the thread on its head but I can refer you to Ravensthorpe nickel mine in Western Australia which was saved from extinction by efforts of, amongst others, Mark Lockyer of Wier. Chase it up & get your eyes opened. ■