Loading Considerations

© 2000 Dr. B. C. Paul revisions 2009Note These slides include screen shots from the Caterpillar Performance ManualEdition 29.

Field Loading Configurations

Depends on the type of equipment used

On the space available Shovels and Hydraulic Excavators

tend to load in one set of ways Backhoes have some variations FEL have some unique ones

Single Truck Loading

Loader near the face

Truck backs up next to the loader on the drivers side(Gives the loader operator abetter view

Loader working into cut in thefaceLoader swings about 120degrees to dump

Advantages of Single Truck Loading

Simple Truck doesn’t have to back tires

into the rockiest areas The shovel faces armor of the

tracks into the dig face Shovel operator has optimized

view of truck bed target

Disadvantages of Single Truck Loading

Backing into place can take around 1 minute and may require a spotter• Loaders expensive and idle• Back time is an unproductive bottleneck• Can form large ques because trucks tend to

bunch

120 degree swing angle can be slow• Manufactures often rate on 90 degree

More Disadvantages Limited Space Available for Oversize

Material• Can set to side• Do a bowling ball drop into truck

• Hydraulic shovels can set - but cable shovels drop bucket bottom open

Extension cord problems with electric equipment• Cord has to cut across truck path• Putting on poles can cost time

Double Truck Loading

Same Arrangement as single truck loading onlythe trucks pull up on bothside

Advantages of Double Truck Loading

Second Loading Spot Allows a second truck to spot during loading operations• Avoids dead time on the loader• Doesn’t help the truck cycle time

other than eliminating some queing

Disadvantages of Double Truck Loading

Still have extension cord problems on electric units

Oversize boulder problem is now even more severe

Forces Loader operator to load on the blind side (most big loaders put the cab to one side of equipment)

Drive By Truck Loading

Shovel Lines up Alongthe face

Trucks pull forward andstop beside the loader

Shovel Swings 90 to 180degrees to dump

Advantages to Truck Drive-By

Greatly Reduced Spotting Time - no backing cycle

Cable doesn’t cross the Trucks Path Can Set Oversize Beside and out of

the way Machine marches on a steady

forward advance Can do in a narrower space

Disadvantages of Drive -By

Often have problems with dipper swinging over the top of the drivers cab• Loader gets revenge for the truck

running over its extension cord• If the dipper comes open your truck

driver can get dead Trucks get to drive those

expensive tires through spills

More Disadvantages

Lack of spotting makes it a one shot that can lead to long swings

Tracks are broadside to long face area

Modified Drive-By (Or Getting Fancy)

Shovel in Drive-By Position Truck Drives up to Shovel as if it

was a drive-by• Loading drops onto a moving target

While the Loading goes for the next bite the truck backs into a single load like position• Shortens swing distance

Advantages

Get most of the positioning advantages of single truck load without the idle spot time

Disadvantages

Dump onto a Moving Target• With swinging over cab can be a real

adventurous feeling for driver Gets the tires into some real rocky

conditions

Backhoe Loading Methods

Backhoe works below grade• Can allow work to be kept off wet pit

floor• can also provide multi-level loading

Backhoes generally need good size machine relative to bucket. Doesn’t wear as well - generally used for special conditions

Can Work Double and Single Truck Loads

Can also Load on Multiple Levels

Multilevel Loading

Double Loading configuration• has extra room for oversize and still

two trucks• Because truck has to come in on right

level does require some additional advance data to send truck to right spot

Can also get 3 position loading• often a bit of overkill

Front End Loader Configurations

FELs are less expensive than the trucks and are mobile

Makes practical to consider more than one loader providing loading service

Limited lift heights make truck match more critical

Tires can tear up bad underfoot

Single Truck Loading

Common Loading Arrangements

Tandom Loading• This time there are two loaders and

the truck backs between Drive By Loading

Chain Loading

Staggered Tandom Loading

My Consideration – What Kind of Turning Radius is

Needed

Turning Radius for Single TruckLoading

How Big a Truck can I Use?

About 15 feet for berm and edge clearance

About ½ truck width

Truck Length

Turning Radius

Checking Out Cat 793(Our biggest option)

43 ft 4 inches long

26 ft 8 inches width

99 ft 2 inches full circleTurn clearance(effect 50 ft turn radius)

Plugging In

About 15 feet for berm and edge clearance

About ½ truck width

Truck Length

Turning Radius

15 feet

43 feet

50 feet

13 feet

121 Feet – I don’t have that

Try 777 (789 was similar to 793 in dimensions)

Turn Radius 43 feet

Width 18 feet Length 32 feet

Checking Out the 777

About 15 feet for berm and edge clearance

About ½ truck width

Truck Length

Turning Radius

9 feet

43 feet

32 feet

15 feet

99 ft < 100 ftJust Works(smaller trucks ok)

For Single Truck Load

Cat 777 is the largest that will work• One of our two smaller would leave us

a little more room for comfort We could look into drive by but we

might want to consider our loader options more