8/13/2019 Step 3 - Determine Haul Distances and Routes

1/2

Step 3 - Determine Haul Distances and Routes

Determine Haul Distances and Routes

(SeeSummaryfor main points)

After production rate, haul distance is the most significant parameter to

be determined. Haul distances and road gradients will be used first to

determine haulage equipment requirements and hours of operation, and

then later to determine road construction and maintenance

requirements and costs.

Begin by dividing the haul roads into segments with obvious gradedifferences. Number the segments in sequence and determine the

gradients of each by determining the elevation gain or loss for each segment divided by its length,

expressed as a percentage. Commonly, a minimum of two segments, and rarely more than six

segments, are required to express haulage gradients in sufficient detail for purposes of determining

haulage productivity and costs.

For an initial estimate, the approximate center of mass of the ore and waste zones can be used as

the starting point for haulage.

Example step 3:

The distances for each road

segment are measured from

the generalized mine plan

map shown inExample step

1.The gradient percentage is

determined by dividing the

elevation change for a segment by the length of the

segment. The distances and gradients for each segment

are listed below. The in-pit haul road gradients are

specified by design to be on gradients of 10%.

More detailed estimates

More preliminary work would be done to define haul road distances and gradients. This might

include detailed pit planning and actual surveying of the haul road routes, or it might simply include

more detailed plotting on a topographic map with more careful measurement of distances and

elevation changes.

Obviously, haul distances, and hence haulage costs, will vary from one part of the pit to another, andfrom one bench to another. Typically, the gradient for the pit haul road will be consistent from the

http://www.edumine.com/xutility/html/documentDisplayEN.htmhttp://www.edumine.com/xutility/html/documentDisplayEN.htmhttp://www.edumine.com/xutility/html/documentDisplayEN.htmhttp://www.edumine.com/xutility/html/documentDisplayEN.htmhttp://www.edumine.com/xutility/html/documentDisplayEN.htmhttp://www.edumine.com/xutility/html/documentDisplayEN.htmhttp://www.edumine.com/xutility/html/documentDisplayEN.htmhttp://parent.loadfigure%28%27../figures/20302.xml');http://parent.loadfigure%28%27../figures/20301.xml');http://www.edumine.com/xutility/html/documentDisplayEN.htmhttp://www.edumine.com/xutility/html/documentDisplayEN.htmhttp://www.edumine.com/xutility/html/documentDisplayEN.htm

8/13/2019 Step 3 - Determine Haul Distances and Routes

2/2

top of the pit to the ultimate bottom, but the total haul distance will increase from bench to bench

as the pit is deepened. The change in haul distance from one bench to another is easily computed

knowing the road gradient and the bench height, e.g. the haul distance differential between two 20

meter benches, assuming a 10% pit road gradient would be 200 meters. The haul distance

differential is the key parameter difference between the cost of mining one block of ore or waste

compared to another. This is a very useful tool for estimating bench by bench costs for pit

optimization procedures, or for life of mine cash flow calculations.

Less detailed estimates

No attempt should be made to estimate mining costs without first making at least a minimal effort

to estimate haulage distances. A rudimentary estimate can be completed without consideration of

road gradients provided haul distances are known. An average truck speed can be assumed for the

hauls, but where actual road gradients are variable, the estimate may be severely in error.

You have covered the following points in Part 2:

Itemized Cost Estimation: Planning.

the advantages of the itemized cost estimatemethod

the twelve steps to an itemized cost estimate how to develop a conceptual mine (step 1) how to determine ore and waste production

rates (step 2)

how to determine haul distances and routes(step 3)