designing and benchmarking mine roads for safe and ... · designing and benchmarking mine roads for...

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Designing and Benchmarking Mine Designing and Benchmarking Mine Roads for Safe and Efficient HaulageRoads for Safe and Efficient Haulage

Roger ThompsonRoger ThompsonAlex Alex VisserVisser

Departments of Mining and Civil & BioDepartments of Mining and Civil & Bio--systems systems EngineeringEngineering

University of Pretoria, South AfricaUniversity of Pretoria, South Africa

Aim of PresentationAim of Presentation

An overview of industry An overview of industry ‘‘bestbest--practicepractice’’in haulin haul-- or roadway designor roadway designAs a basis for reducing accident As a basis for reducing accident potential associated with poorly potential associated with poorly design roadsdesign roads

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Scope of Scope of PresentationPresentation

IntroductionIntroductionMine Road Design CategoriesMine Road Design CategoriesTransport and Mining Accident StatsTransport and Mining Accident StatsMine Haul Road Safety Audit SystemMine Haul Road Safety Audit SystemConclusionsConclusions

Introduction Introduction --application scenarioapplication scenario

Historically, mine road design was empirical, adHistorically, mine road design was empirical, ad--hoc and not always focused on the accident hoc and not always focused on the accident potential of poor design workpotential of poor design workTraffic volumes are low, but highly variable over Traffic volumes are low, but highly variable over an extensive network of unpaved roadsan extensive network of unpaved roads

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Historically, mine road design was Historically, mine road design was empirical, adempirical, ad--hoc and not always focused hoc and not always focused on the accident potential of poor design on the accident potential of poor design workwork

Introduction Introduction --application scenarioapplication scenario

Components of a mine road design Components of a mine road design include;include;

geometric design (alignment)geometric design (alignment)structural design (thickness and strength)structural design (thickness and strength)functional design (surfacing)functional design (surfacing)maintenance management (blading, grading)maintenance management (blading, grading)

Mine Road DesignMine Road DesignCategoriesCategories

Functional design

BA

SIC

DA

TA

Structural design

Maintenance Management

System

Dust Palliative Management

Within limits –no treatment required

Chemicalpalliation

Water-based spraying

Modify wearing courseselection

Dust ModelPalliative

Performance Model

Geometric design

Functional design

BA

SIC

DA

TA

Structural design


System



Chemicalpalliation




Performance Model

Geometric design

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Integrating the Categories of a Haul Integrating the Categories of a Haul Road DesignRoad Design

Functional design

BA

SIC

DA T

A

Structural design


System



Chemicalpalliation




Performance Model

Geometric design

What are the safety critical issues in What are the safety critical issues in road design?road design?

Functional design

BA

SIC

DA T

A

Structural design


System



Chemicalpalliation




Performance Model

Geometric design

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What are the safety critical issues in What are the safety critical issues in road design?road design?

Functional design

Geometric design

Horizontal design and alignment –sight distances

Horizontal design Horizontal design and alignment and alignment ––sight distancessight distances

Vertical design and alignment

Vertical design and Vertical design and alignmentalignment

Berm designBermBerm designdesign Wearing course selection

Wearing course Wearing course selectionselection

Wearing course dust treatments

Wearing course dust Wearing course dust treatmentstreatments

Skid resistance and loose material -

stoniness

Skid resistance and Skid resistance and loose material loose material --

stoninessstoniness

Structural design

Geometric DesignGeometric Design

Use a structured approach to geometric Use a structured approach to geometric design;design;

Firstly, a set of mine geometric design Firstly, a set of mine geometric design standardsstandardsSecondly, the conceptual designSecondly, the conceptual designFinally, the Finally, the ‘‘asas--builtbuilt’’ designdesign

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Conceptual road vertical and horizontal layout

Conceptual Conceptual road vertical road vertical and horizontal layoutand horizontal layout

Truck minimum braking distances (unassisted)Truck typical speeds up- and down-gradeTruck sight distance requirements

Truck minimum braking distances (unassisted)Truck typical speeds up- and down-gradeTruck sight distance requirements

Lay out the road according to 9-11% max sustained gradeAssume initial width of road 4,5x width of truck including berms and drainsHighlight location of

SwitchbacksCurves (horizontal and vertical)Intersections

Lay out the road according to 9-11% max sustained gradeAssume initial width of road 4,5x width of truck including berms and drainsHighlight location of

SwitchbacksCurves (horizontal and vertical)Intersections

Examine conceptual design following vertical and horizontal alignment requirements

Examine conceptual Examine conceptual design following design following vertical and horizontal vertical and horizontal alignment alignment requirementsrequirements

Locate switch-backs on section of road with no vertical gradesLocate switch-backs on section of road with no vertical grades

Intersection designIntersection designIntersection design

Drainage designDrainage designDrainage design

Locate intersections on level with adequate sight, curves and run-out.Locate intersections on level with adequate sight, curves and run-out.

Design drainage system, especially road-side, culvert location, switchback and intersection drainage.

Design drainage system, especially road-side, culvert location, switchback and intersection drainage.

Separate vertical and horizontal curves where possibleSeparate vertical and horizontal curves where possible

Horizontal design and alignment

Horizontal design and Horizontal design and alignmentalignment


Vertical design and Vertical design and alignmentalignment Establish minimum vertical curve lengths

based on change in grade (%) or headlight distance for sag curves, for minimum stopping distance

Establish minimum vertical curve lengths based on change in grade (%) or headlight distance for sag curves, for minimum stopping distance

Establish minimum horizontal curve lay-back based on braking distanceEstablish minimum horizontal curve lay-back based on braking distance

Establish optimum grade 9-11%,.Establish optimum grade 9-11%,.For every 1% increase in rolling resistance over 2%, reduce optimum grade by 1%

For every 1% increase in rolling resistance over 2%, reduce optimum grade by 1%

Establish cross-fall value or camber (2-4%). Laden lane at ‘uphill’ side of cross-fall.


Where pit geometry does not allow for minimum requirements, apply speed limit to each curve not meeting requirements


Establish width of road according to;Truck widthTraffic (1-2 lanes)Safety berm at outslope and centre of road


Establish run-outs based on curve super-elevation, cross-fall and camber.Establish run-outs based on curve super-elevation, cross-fall and camber.

Berm designBermBerm designdesign

Design berms (median and outslope) with largest truck and speed in mind.Design berms (median and outslope) with largest truck and speed in mind.

Establish minimum horizontal curve radius based on speed of truck and super-elevation (5% max)






Final geometric design

Final geometric Final geometric designdesign

Drainage re-evaluationDrainage reDrainage re--evaluationevaluation

Horizontal design and alignment

Horizontal design and Horizontal design and alignmentalignment


Vertical design and Vertical design and alignmentalignment Establish minimum vertical curve lengths

based on change in grade (%) or headlight distance for sag curves, for minimum stopping distance

Establish minimum vertical curve lengths based on change in grade (%) or headlight distance for sag curves, for minimum stopping distance

Establish minimum horizontal curve lay-back based on braking distanceEstablish minimum horizontal curve lay-back based on braking distance

Establish optimum grade 9-11%,.Establish optimum grade 9-11%,.For every 1% increase in rolling resistance over 2%, reduce optimum grade by 1%

For every 1% increase in rolling resistance over 2%, reduce optimum grade by 1%







Establish run-outs based on curve super-elevation, cross-fall and camber.Establish run-outs based on curve super-elevation, cross-fall and camber.

Berm designBermBerm designdesign

Design berms (median and outslope) with largest truck and speed in mind.Design berms (median and outslope) with largest truck and speed in mind.







Final geometric design

Final geometric Final geometric designdesign

Drainage re-evaluationDrainage reDrainage re--evaluationevaluation

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Well documented Well documented –– but take special but take special care with;care with;

Ramps Ramps –– width, junction visibility, spillage width, junction visibility, spillage and drainageand drainage



Ramps Ramps –– width, junction visibility, spillage width, junction visibility, spillage and drainageand drainageSwitchbacks and curves Switchbacks and curves –– larger radius , larger radius , supersuper--elevated and sight / stopping elevated and sight / stopping distancesdistances

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Ramps Ramps –– grade breaks and max productive grade breaks and max productive total resistance (grade + rolling) total resistance (grade + rolling) Switchbacks and curves Switchbacks and curves –– larger radius , larger radius , supersuper--elevated and sight / stopping elevated and sight / stopping distancesdistances


Berms Berms –– especially centre especially centre bermsberms –– large large enough to arrest vehicle enough to arrest vehicle –– but visibility but visibility issues for smaller vehiclesissues for smaller vehicles

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BermsBerms –– especially centre especially centre bermsberms –– large large enough to arrest vehicle enough to arrest vehicle –– but visibility but visibility issues for smaller vehiclesissues for smaller vehiclesDrainage Drainage ––crosscross--fall or camber and fall or camber and roadside drainage ditchesroadside drainage ditches


BermsBerms –– especially centre especially centre bermsberms –– large large enough to arrest vehicle enough to arrest vehicle –– but visibility but visibility issues for smaller vehiclesissues for smaller vehiclesDrainage Drainage ––crosscross--fall or camber and fall or camber and roadside drainage ditchesroadside drainage ditches

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Make sure that what you have Make sure that what you have designeddesigned is is built and maintained correctlybuilt and maintained correctlyMake use of signage to assist grader and Make use of signage to assist grader and truck operators to make maximal use of the truck operators to make maximal use of the roadroad

Structural DesignStructural Design

Load carrying capacity of the road. Design Load carrying capacity of the road. Design for;for;

Better pavement response to applied loadsBetter pavement response to applied loadsReduced deflection on surface and Reduced deflection on surface and deformation in subdeformation in sub--grade or ingrade or in--situsitu

= Better directional stability of truck= Better directional stability of truck

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Structural DesignStructural DesignCase StudyCase Study

Structural design comparisons0

250500750

1000125015001750200022502500

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

Vertical (micro) strain in pavement

New

Des

ign

Laye

r De

pths

(mm

)02505007501000125015001750200022502500

Old Design New Design

Old

Des

ign

Laye

r De

pths

(mm

)

W/course

Fill layer

Layer 3In-situ

Selectedblasted waste

rock

Layer 3In-situ

W/course

Wearing course

Base

In-situ (soft)

Wearing course

Base

In-situ (soft)

Wearing course

Base

In-situ (soft)

Wearing course

Base

In-situ (soft)

Wearing course

Base

In-situ (soft)

Wearing course

Base

In-situ (soft)

Functional DesignFunctional Design

Wearing course material selection. Design Wearing course material selection. Design for;for;

Reduced wearing course Reduced wearing course ‘‘defectsdefects’’ –– especially especially dustiness and loose materialdustiness and loose materialReduced deterioration rates and maintenance Reduced deterioration rates and maintenance frequencyfrequency

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Functional DesignFunctional DesignWearing Course Selection

0

50100

150

200

250300

350

400

0 5 10 15 20 25 30 35 40 45 50

Grading Coefficient

Shr

inka

ge P

rodu

ct

.

Recommended (1) Recommended (2)

Dustiness Slippery when wet

Loose materialLoose stonesTyre damage Corrugates

050

100150200250300350400450500550

0 10 20 30 40 50

Grading coefficient

Shrin

kage

pro

duct

.

DustinessWet skid resistance

Loose stoniness

Corrugations

Loose material

Dry skid resistance

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Practical Practical ApplicationApplication

13

050

100150200250300350400450500550

0 10 20 30 40 50

Grading coefficient

Shrin

kage

pro

duct

.

Dustiness

Loose stoniness

Dry skid resistance

1



Consider the use of dust palliatives to Consider the use of dust palliatives to improve wearing course performance BUT;improve wearing course performance BUT;

Will not Will not ‘‘fixfix’’ an inherently poorly design road an inherently poorly design road (expensive)(expensive)Require dedicated and modified road Require dedicated and modified road management approach management approach –– one product doesnone product doesn’’t t fit all types of applicationsfit all types of applications

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Transport & MiningTransport & MiningAccident StatisticsAccident Statistics

About half of all attributable transport accidents are About half of all attributable transport accidents are roadroad--design related;design related;

Geometric design problemsGeometric design problemsFunctional design problemsFunctional design problemsHuman errorHuman errorNonNon--standard practicesstandard practices

Percentage of road design factors implicated in attributable T&M accidents

Human Error14%

Geometric10%

Functional8%

Practices9%

Not attributable53%

Other issues5%

Road design related accidents

47%

Maintenance1%

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No formal design

Ad-hoc design

Generic design

Formal design

High accident potential –

‘unforgiving’conditions

Heightened safety –

accommodate human error

Human error and non-standard acts 47%

Road design factors 43%

Vehicle mechanical and 'other' factors 10%

19%25%

14%3%

1,5%4%1,5%

Heightened safety –

accommodate human error

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Mine Haul Road Mine Haul Road Safety AuditsSafety Audits

The objectives of using a safety audit systems are;The objectives of using a safety audit systems are;To provide a structured appraisal of potential safety To provide a structured appraisal of potential safety problems for roadproblems for road--users and road operatorsusers and road operatorsTo ensure that suitable measures for the problem elimination To ensure that suitable measures for the problem elimination are fully evaluated and appliedare fully evaluated and applied


The benefits of using a safety audit systems are;The benefits of using a safety audit systems are;A potential reduction in the number and severity of T&M A potential reduction in the number and severity of T&M accidentsaccidentsHaul road safety is given greater prominence in the minds of Haul road safety is given greater prominence in the minds of roadroad--user, operators and designersuser, operators and designersThe need for costly remedial work is reduced (if the audit is The need for costly remedial work is reduced (if the audit is implemented at the design stage)implemented at the design stage)

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Audit StageD

esig

n C

ompo

nent

A

sses

sed

Feasibility

General Topics

General Design Issues

Alignment

Junctions

Environmental

Road Users


Audit Stage

Des

ign

Com

pone

nt

Ass

esse

d

Draft Design

General Topics


Alignment

Junctions

Environmental

Road Users

Signs and lighting

Other

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Audit StageD

esig

n C

ompo

nent

A

sses

sed

Detailed Design

General Topics


Alignment and cross section

Junctions

Environmental

Road Users

Signs and lighting

Physical Objects

Construction

Other


Audit Stage

Des

ign

Com

pone

nt

Ass

esse

d

Pre-Opening

General Topics



Junctions

Road Users

Signs and lighting

Physical Objects

Maintenance

Finishing

Training road-users

Other

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Audit StageD

esig

n C

ompo

nent

A

sses

sed

Existing roads

General Topics



Junctions

Road Users

Signs and lighting

Physical Objects

Maintenance

Training road-users

Road-user feedback

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Practical Practical ApplicationsApplications

ID the ID the ““KPSKPS”” –– KKey ey PPerformance erformance SSegments on egments on your road network;your road network;

SafetySafety--critical segments critical segments –– intersections, ramps, intersections, ramps, switchbacks, etc.switchbacks, etc.High speed high tonnage roadsHigh speed high tonnage roads

Prioritize remediation on these segmentsPrioritize remediation on these segments


Visual inspections Visual inspections –– mark roads where maintenance mark roads where maintenance should be done with red, yellow or green cones should be done with red, yellow or green cones ––prioritize.prioritize.Record maintenance intervention (what done) and Record maintenance intervention (what done) and frequencies (how often) per segment frequencies (how often) per segment –– establish a establish a rehabilitation schedule rehabilitation schedule –– prioritize BUTprioritize BUT……..

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Why does the segment have safetyWhy does the segment have safety--critical issues?critical issues?Poor design and / or build specs;Poor design and / or build specs;

GeometricsGeometricsStructure (layer works and materials)Structure (layer works and materials)Functional (wearing course)Functional (wearing course)

Investigate the rootInvestigate the root--cause of the undercause of the under--performance performance beforebefore deciding on a remediation deciding on a remediation strategystrategy

ConclusionsConclusions

The ProblemThe Problem

Poor or no haulPoor or no haul-- and roadway design often leads and roadway design often leads to otherwise avoidable T&M accidentsto otherwise avoidable T&M accidents

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The ChallengeThe Challenge

How to design a haulHow to design a haul-- or roadway that is more or roadway that is more accommodating for driver error?accommodating for driver error?How to benchmark the suitability of existing How to benchmark the suitability of existing roads?roads?How to remediate haul road problems?How to remediate haul road problems?


The Way AheadThe Way Ahead

Training mine staff in the principles of good road Training mine staff in the principles of good road designdesignThe use of more formal geometric and functional The use of more formal geometric and functional design procedures to assist in eliminating design procedures to assist in eliminating accidentsaccidentsThe use of a haul road design audit system to The use of a haul road design audit system to evaluate proposed or current road design and evaluate proposed or current road design and safety performancesafety performance

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Additional ResourcesAdditional Resources

TechnologyTechnologywww.advminingtech.com.auwww.advminingtech.com.auwww.acumine.comwww.acumine.comhttp://jnbqp1.corporate.aaplc.com/hme (by invitation)http://jnbqp1.corporate.aaplc.com/hme (by invitation)

Road design guidelines and performance Road design guidelines and performance benchmarkingbenchmarking

www.up.ac.za/academic/mining/research/research_frame.htmwww.up.ac.za/academic/mining/research/research_frame.htm

Road design and management training coursesRoad design and management training courseswww.ceatup.comwww.ceatup.com

Acknowledgements Acknowledgements

Parts of the work described in this paper was carried out as parParts of the work described in this paper was carried out as part of the other t of the other mines research program of the Mine Health and Safety Council Safmines research program of the Mine Health and Safety Council Safety in ety in Mines Research Advisory Committee. The authors gratefully acknoMines Research Advisory Committee. The authors gratefully acknowledge the wledge the financial assistance and support received from the SIMRAC and SIfinancial assistance and support received from the SIMRAC and SIMOT MOT committees.committees.

Details may be found from;Details may be found from;www.simrac.co.za/report/Reports/thrust5/oth308/oth308.htm. www.simrac.co.za/report/Reports/thrust5/oth308/oth308.htm.

designing and benchmarking mine roads for safe and ... · designing and benchmarking mine roads for...

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