this topic has been and is highly investigated, reviewed and cost analogies have been done to confirm the economies of using mining haul truck and the cost of drivers, benefits, etc vs conveying the material from the face.

Generally, any time we can eliminate MAN POWER, we eliminate wages, vacations, benefits, problems with sick days, fluctuating operating costs due to varying degrees of experience, capital cost of new trucks, varying costs of ever changing haul distances due to moving distance of ROM face.

Track mounted primary crushing or screening equipment is the craze now and proven to eliminate much costs at the face and feeding their processed material directling onto a long feed conveyor is becoming and is very popular now.

kind regards......

George Baker ■

The cost comparative analysis is done as per usual rules / methods of cost comparison, which is not necessary to described here. This will be partially affected by locality and country.

The choice of equipment and cost comparison for material transport can be broadly divided into two types of situations.

A) Cross country direct transport from one point to other point

B) Material transport in mining operation, etc.

For serial number A, the owner will just have choice mainly based on cost comparison. However, this will be very much affected by availability of land, disturbance to the environment or surrounding people.

For serial number B, the choice depends upon viability of the transport in the mining / equal situation. So, here apart from the cost, the feasibility of using either type of arrangement will also be dominant.

It has been observed that choice is also affected by the liking of concerned people. For example, in some countries people prefer belt conveyors more whereas at other places there is more tilt towards truck haulage. Thus some people give more weightage to the particular advantage whereas some people give more weightage to the others advantage i.e. sensitivity to particular aspects.

Regards,

Ishwar G Mulani.

Author of Book : Engineering Science and Application Design for Belt Conveyor.

Email : parimul@pn2.vsnl.net.in

Tel.: 0091 (0)20 5882916 ■

A Few Subjective Comments:

There are many conditions that weigh the financial and risk based results. A few points are:

1. Civils:

a) Cut and Fill for overland, incline or decline conveyors will favor belts beyond 1 km in length.

b) Greater the slope (>10%) the more likely the conveyor will beat the truck. Maintenance of roadways can cause significant cost to project.

c) Heavy rains impact road design and maintenance. These point have a small impact on well engineered conveyors. Poor soil favors conveyor over truck. T

d) The class of engieered soil can further favor the belt.

2. Curved Path - routing around obstacles with horizontal radii > 800 m for conventional belting and >200 m radii for pipe conveyors will favor belt conveyors.

3. Tonnage -- > 5MMTpa will usually favor belts.

4. Operating costs - improvements in belt rubber compounds continue to reduce belt operating costs. Thus, power efficiency for belts of all sizes continues to advance, whereas truck efficiency is only seen to increase with larger handling scale (ie greater tons handled).

5. Truck Advantage

a) Greater advantage is seen by trucking when there is a need for increasing dynamic allocation of truck fleet as mine plan changes over time.

b) Breakdown replacements can be contracted and may be of short duration allowing to keep stockpile sizes to a minimum.

A Monte Carlo transportation system simulation would give further evidence to the financial benefit and risk assessment of belt vs truck or visa versa.

Lawrence Nordell

Conveyor Dynamics, Inc.

www.conveyor-dynamics.com ■

In regard to your posting the rule is cost per ton mile to determine overal cost. this means you must determine all costs

in a simulation and divide it by the haulage length. then you can get a good idea of the costs but you must get all of the information first!!!!!!!!!!!!!!!!!!!!!

You do not mention conveyor size as in capacity wanted, length of haul route, length of the return route, electricity costs and labor costs, not to mention cost per hour of overhead- a 36 inch conveyor will run $2,000,000.00 per mile so you must take into account, electricity to run it, installation costs is it cable supported or steel supported? what is the grade of conveyor belt needed?,

are emergency stops required or or they standard equipment?

Transfer points are another issue, a 36 inch belt usually has a transfer point anywhere from 1500 to two thousand feet depending on slope, material weight, run of mine ore size etc.

The big thing is friction, as you are creating huge amounts of friction on both the out bound leg and return legs of a belt line and the electric motors and reduction gears are pulling against all that weight just to run. splicing is another big issue, do I want to use mechanical splicing or vulcanized? the mechanicals cost less

but the vulcanized splices are the best.... I would be glad to help you with this if you like -contact me at lzaharis@lightlink.com ■

In January 2004 a colloquium was held at University of Clausthal, Germany.

One lecture was about the topic: economical comparison of continous and discontinous transportation in open pit mine Eagle Bute, USA.

Lecture was held by Dipl.-Ing. Edmund Köppen and Dipl.-Ing. Michael Schütze, both RAG Coal International AG, Essen, Germany.

I think a copy of the lecture is available from them. ■