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Conveyors 301John Garrison

John Garrison

▪ Vice President of Sales

▪ Superior Industries

▪ Previous experience

▪ Terex MPS

▪ Motion Industries

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Stockpile Segregation

What is segregation?

▪ Separation of material by particle size

▪ Uneven concentration of coarse and fine

▪ Poor structural and textual characteristics

▪ Shorter life expectancy of final product

Effects of Segregation

▪ Penalties of > 50¢ per ton

▪ Decreased value of product

▪ Rejection of entire stockpile

▪ Labor to rebuild is prohibitive

▪ Degraded company reputation

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Stockpile Segregation

▪ Stockpiling Problems

▪ Causes of Stockpile Segregation

▪ Preventing Segregation

▪ Telescoping Radial Stacking Conveyor

▪ Desegregated Stockpiles

▪ Conveyor Automation

Where does segregation occur?

▪ After product is crushed, screened, blended

▪ Likely locations:

▪ Stockpile

▪ Handling and transport

▪ Storage (bins and hoppers)

▪ During application of final mix

Problems Caused by Segregation

▪ Fluctuating gradation makes it impossible to

produce acceptable asphalt or concrete

▪ Too many fines? Shortage of concrete paste

or asphalt mix (stiff consistency)

▪ Too many large particles? Excess amount of

paste or asphalt (runny consistency)

▪ Roads have poor structural integrity and

shorter lifespan

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Causes of Stockpile Segregation

Degree in Variation of Particle Size

Ratio less than 2:1

Minimal segregation

Ratio greater than 2:1

Higher degree of segregation

Bouncing on Belting

Most stockpiles created by conveyors

Belt bounces when crossing idlers

(Due to belt sag between idlers)

Finer particles settle to bottom

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Separation at Discharge Pulley

▪ At discharge, top particles travel

at greater velocity than bottoms

▪ Larger particles travel further

from conveyor, smaller closer

▪ Fine materials cling to belt and

end up in front side of pile

Effect of Overrun

Fine

Medium

Course

Wind Effect on Falling Material

▪ Wind effects trajectory

▪ Greater effect on fine material

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Preventing Segregation

Building with Trucks

▪ Dump into separate piles...minimize overrun

▪ If loader, raise material to full bucket height

▪ Better blends the material

▪ Never drive on material...degrading

Building with Dozers

▪ Allows layers, minimizes segregation

▪ If material comes by truck, inclined layers

▪ If by conveyor, horizontal layers

▪ Avoid pushing material over pile

▪ This results in overrun

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Disadvantages of Dozers

▪ Heavy equipment compacts and crushes

▪ Degradation and contamination

▪ Dealing with segregation upon reclaim

▪ Extra labor and equipment is costly

Fixed Height Radial Stackers

▪ Moves left to right (radially)

▪ Blended more than conical pile

▪ Discharge height = degree of segregation

▪ Fines separated more as height increases

Telescoping Chute

▪ Minimizes effect of wind

▪ Extends from pulley to pile

▪ Limits free fall of material

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Variable Height Radial Stackers

▪ Distance from head pulley minimized

▪ Reduces free falling material

Windrow Concept

Windrow Concept

▪ Building stockpiles in layers

▪ Each layer consists of series of windrows

▪ Segregation pattern is repeated

▪ When reclaiming, no need to blend

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Conical Stockpile

Fine

Medium

Course

Windrow Stockpile

Fine

Medium

Course

Methods of Building Windrows

Tripper Conveyor Telescopic Stacking Conveyor

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Tripper Conveyor System

▪ Stationary applications

▪ Fixed height

▪ Segregation by wind

Telescoping Conveyors

Telescoping Conveyors

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Telescoping Conveyors

Manual Control

Limit Switch Automation

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PLC Controlled

▪ Computer receives data from inputs

▪ Controls various components

▪ Encoder mounting positions:

▪ Winch cable to monitor stinger

▪ Wheel to monitor radial position

▪ Discharge point to monitor pile height

▪ Everything is customizable

Partially Desegregated Stockpile

▪ Overrun can still be a problem

▪ Ends of piles subject to segregation

▪ 40% of final pile is overrun

▪ Prevent material from rolling over edges

Overrun

No Overrun

Fully Desegregated Stockpile

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Aggregate Industries

▪ Littleton Quarry

▪ 35-miles northeast of Boston

▪ Project to reduce cost per ton

▪ Relocate plants closer to quarry face

▪ (2) 36” x 150’ TeleStacker® Conveyors

▪ Cut footprint by 43%

▪ Eliminate 2,200’ of overland conveyor

Aggregate Industries

▪ “Material handling delivered quick returns

and is the biggest efficiency factor.”

Chad Abramson, Plant Manager

▪ Eliminated:

▪ Double handling of material

▪ Loaders and haul trucks

▪ 8,000 ton capacity fixed stackers

▪ 28¢ per ton savings

Before

Aggregate Industries

▪ Creating fully desegregated, kidney bean

shaped stockpiles

▪ Stockpiling 70,000 tons under each

TeleStacker® Conveyor (+89%)

▪ “Environmentally friendly alternative that

makes our neighbors happy.”

After

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Conveyors vs Rolling Stock

Factors to Consider

▪ Cost benefit

▪ Product quality

▪ Topography

▪ Environmental concerns

Conveyor Advantage

▪ Limited inflationary effect

▪ Improved product quality

▪ Continuous flow

▪ Environmentally friendly

▪ Design flexibility

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CalPortland - Santosh Plant

▪ Material handling from extraction to plant

▪ 2-miles of overland conveyor

▪ Replaced multiple haul trucks

▪ Robert Hostettler, plant manager:

▪ Less harmful chemicals released

▪ Electricity prices more stable than fuel

▪ Smaller operational footprint

▪ Much less manpower required

▪ Components can be reused when finished

Overland Conveyor vs Haul TruckHaul Trucks Conveyors

Capital Purchase Price $300,000 Capital Purchase Price $250,000

Length of Haul 1,050-feet Conveyor Length 1,050-feet

Number of Trucks 2 Trucks Net Elevation Change 40-feet

Load/Truck 40 Tons Belt Width 42-inches

Truck Cycle Time 10 minutes Estimated Horsepower 50 HP

Depreciation Schedule 7 years Number of Sections 1

Expected Life 30,000 hours Site Preparation $10,500

Operation/Days 10 hours Operation/Days 10 hours

Days of Operation/Week 5 days Days of Operation/Week 5 days

Labor w/ Benefits $25.00 per hour Labor w/ Benefits (Per Hour) $25.00 per hour

Maintenance/Fuel $56.00 per hour Electricity Cost per kW $0.08 per hour

Lifetime Capital Maintenance $70,000 per truck Tons Per Hour 480

Overland Conveyor vs Haul Truck

Haul Trucks Conveyors

Cost Per Ton $ 0.43 $ 0.03

Conveyor Savings/Ton $ 0.40

Savings Per Day $ 1,920

Savings Per Week $ 9,600

Savings Per Month $ 41,600

Savings Per Year $ 449,200

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QUESTIONS?