Andres Oritz - Paterson & Cooke Australia

Current Technologies for the Hydrotransport of Mineral Sands Streams, Perth 2017, Slide 1

www.PatersonCooke.com

Current Technologies for the Hydrotransport of Mineral Sands StreamsAndres Ortiz

17th Mineral Sands Conference, Perth 2017


Formed in 1991

Engineering group specialist in slurry pipeline systems

130+ staff PerthCape

Town

Johannesburg

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Lima

Denver

VancouverCalgary

Sudbury

Cornwall

About Paterson & Cooke

Source: OCP Group - Morocco


Overview of operating pipeline systems

Hydrotransport challenges

Recommendations:

• Test work

• Pipeline design

• Implementation & Commissioning

Where to next?

Outline


Run of Mine pipelines

• From mining areas to process plant

Residue pipelines

• Fines/slimes (only), often with high clay fractions and non-Newtonian

• Co-disposal (slimes + sand)

In-pit disposal / residue storage facility

Underground mine backfill (hydraulic fill)

Concentrate (HMC / HMS) pipelines

• First system commissioned in 1986 (NZ Iron Sands), 20 km pipeline

• Projects ongoing for longer systems

Mineral Sands Pipeline Systems

• Usually short distance (5 km max.)

• High content of fines (-45 µm)

• High rheology

• Solids concentration (40% to 50%m)

• Cost effective solution for +10 km

• Very low fines (-45 µm) content

• Low rheology

• Higher solids conc. (+50% to 65%m)

• Minimising pipeline wear is a

challenge

• Usually short distances with booster

stations or in-line boosters


Mineral Sands Pipelines

Rehabilitation

Mining area – ROM pipelines

Fines waste disposal

Mining Area Outside Mine Boundary to Export Terminal Facilities

or Processing Plant

Water pipelines

Return water

Residue pipeline

Coarse waste material

HMC pipeline


Run-of-Mine (ROM) Pipelines

Technology used for the reclamation of gold tailings in South Africa has been transferred to mineral sands operations

25 to 40 bar water jets cut the face and the slurry is sluiced to the plant


HMS Tailings – Typical Flowsheet

Sand Slimes

23%m

35%m

Source:

Hutcheson (2000)

“Depositional & Geotechnical

Characteristics of Mineral

Sands Thickened/Paste

Tailings”

STACKER

CYCLONE

REHAB

BACKFILLING

WATER TO PROCESS

WATER DAMS

FEL

MAKE-UP

WATER

TRANSFER

SUMPWALL

RAISING

DEWATERING

STOCKPILEMIX

TANK

TO RESIDUE DAM

COARSE SAND

FROM PWP

TO REHAB

DILUTION/

FLUSHING WATER

VSD

FEEDER

SLIMES

FROM PWP

THICKENERS

WATER TO PROCESS

WATER DAMS

AUTO SAMPLER

VSD

VSD

VSD

VSD


Yield stress range for a sand:slimes ratios of 7:3 and 8:2 sample

HMS Tailings – Slurry Characteristics

Slurry Density (t/m³)

Yie

ld S

tress (

Pa

)

1.10 1.20 1.30 1.40 1.50 1.60 1.70

0

40

20

60

80

100

120

Slurry Density (t/m³)

Yie

ld S

tress (

Pa

)

1.10 1.20 1.30 1.40 1.50 1.60 1.70

0

40

20

60

80

100

120

Ketchup 15 Pa

Iron Ore Tailings, 64%m 100 Pa

Crucial to identify the

rheology range for the design


HMS Tailings – Discharge Methods

Co-disposal sand and slime mixture being deposited on slopes for

rehabilitation

Slimes placed in paddocks

Source: J. M. Rusconi, P. Goosen, J. Venter “Co-Disposal Plant and Distribution System to Allow the Proper Closure of Exxaro’s Hillendale Mine Site”, 12th International Seminar on Paste

and Thickened Tailings, Chile


Short haul trucking

• Within mine fence, < 20 km

Long haul trucking

• Beyond mine fence, up to 75 km

Overland conveyor

• Single flight up to 50 km or more

• 10% grade, horizontal radius limits, dusting

Ore trains / rail

• In WA = unlimited distance

• 1% maximum grade when loaded = longer routes, crossings costly

• Continuous power supply along route if electrified

Slurry Pipelines – fine particle transport

• Viable over long distances

• Water, particle preparation (grinding and drying) requirements

• Steep terrain limits (10% to 15% grade)

Bulk commodity transport options and Slurry Pipelines

Haul roads, grade limits, high running costs, flexible, can be contracted


HMC Pipelines – Typical Flow Sheet

HEAD PUMP

STATION

HMC

STOCKPILE

FEED

BINPD

PUMP

PD

PUMP

OVERLAND PIPELINE OVERLAND PIPELINE

WATER

CHARGE

PUMPS

BOOSTER PUMP STATION (?)

(Depending on length and profile)

RECEIVING

TANK

HMC

STOCKPILE

MINE COMPLEX


HMC Pipelines – Typical Flow Sheet – Offshore SBM

AT MINE

seabed

SLURRY

PREP

SHIP

Single Buoy

Mooring (SBM)

overland

HMC STOCKPILE

Process Water

Dam

main seawater pipeline

slurry return water

main seawater intake

Source: www.nzsteel.co.nz/new-zealand-steel/the-story-of-steel/the-mining-operations/taharoa-mine-site/

http://www.nzsteel.co.nz/new-zealand-steel/the-story-of-steel/the-mining-operations/taharoa-mine-site/


Solids SG >4

Round/well graded particles

HMC Pipelines – Slurry Characteristics


Top size <1 mm

Practically no fines (-45 µm)

Samples from two operations both show similar well graded deposits with little variation


0 %

10 %

20 %

30 %

40 %

50 %

60 %

70 %

80 %

90 %

100 %

10 µm 100 µm 1000 µm

Particle Size

Design HMC HMC (Sample 1) HMC (Sample 2)

HMC (Sample 3) HMC (Sample 4)

Cum

ula

tive P

erc

enta

ge P

assin

g b

y M

ass


Settling slurry

Transport velocity typically +3 m/s

Solids concentration >50% by mass (about 20% by vol.)



HMC Pipelines – Settling (visual demonstration)


Hydraulic models available are suitable for determining:

• minimum transport velocity and

• estimate pressure gradients

Challenges are related to implement these findings:

• High operating velocity high wear and discharge pressure

• Pumping equipment PD pumps are required above 5 MPa (50 bar)

• Slurry behaviour Can be restarted if the pipeline shuts down on slurry?

Risk management

• Buried pipeline where possible

• Leak detection systems

• Pigging and wear monitoring

HMC Pipelines – Design Challenges

Pumping technology??Pipe Material??


Pumping equipment requirements

More than one pump station may be needed depending on distance and static head

HMC Pipeline – Implementation Challenges

Supplied by Feluwa pumps


Can it restart after shutting down on slurry?


After 15 h shutdown


Can it restart after shutting down on slurry?



When transporting HMC slurry at 50%m and shutting down the pipeline, in a horizontal pipeline the settled bed occupies approximately 29% of the available flow area.

To re-start the pipeline, the velocity above the settled bed must be sufficiently high to re-suspend the settled bed. As the bed is eroded the pump speed increases to the design flow rate.

Bed concentration and pipeline re-start

AVAILABLE FLOW AREA FOR RE-START

SETTLED BED WHEN SHUTDOWN WHILE TRANSPORTING A 50%M SLURRY

(29% OF FLOW AREA)

40% mass

50% mass

60% mass

68% mass

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0.00 0.02 0.04 0.06 0.08 0.10 0.12

Perc

ent

of

tota

l pip

e a

rea

Height of settled bed (m)

Area of settled bed in a

pipeline transporting

50%m HMC at

shutdown


Minimise pipeline wear

Option of using polyurethane (PU) lining is expensive in most cases

HDPE lining provides good results in specific conditions


Source:

Venton and Cowper (1986)

Hydrotransport 10

The New Zealand Steel

Ironsand Slurry Pipeline

Special coupling designed for PU pipeline

Source:

Thomas (2011)

Slurry Pipelines Conference

Innovations – Improving the

Efficiency of Slurry Transport


HDPE lining technology


Source: United Pipeline Systems


Relative wear tests


P&C Proprietary Accelerated Wear Test Rig


Field wear tests



Where to Next?

Source:

Sivakugan et al (2006)“Geotechnical considerations in mine backfilling

in Australia”

Underground residue disposal, e.g. hydraulic backfill


Where to Next?

Source:

Sivakugan et al (2006)“Geotechnical considerations in mine backfilling

in Australia”

Underground residue disposal, e.g. hydraulic backfill


Slurry pipelines are an accepted alternative to conventional bulk minerals handling and provide opportunities to develop orebodies that are remote from the process plant

Where to Next?

Receiving Station

at Process Plant

Head Pump Station at Mine

Booster Pump

Station 1

Booster Pump

Station 2


Mineral sands operations are reliant on slurry pipeline systems for many process streams:

• Run of Mine from orebody to process plant

• Residue disposal, either fines and coarse as separate streams, or co-disposal

• Opportunities for HMC transport from mine site to process plant

These streams all have different slurry transport requirements:

• Identify rheology design range and optimum solids concentration is crucial for tailings/residue pipeline systems design

• Good experience available in the implementation of these different process flow streams

• Test work is required to determine the material properties and to optimise CAPEX and OPEX

Although HMC is a fast settling slurry, restarting after shutdown on slurry is feasible due to the well graded size distribution and rounded particle shape.

HMC pipeline should be considered as a viable alternative to conventional bulk handling solutions

Conclusions


Thank you

Contact us:

Andres Ortiz

Director, P&C Australia

59 Walters Drive, Osborne Park, WA 6017

[email protected]

+61 4 3911 9031

mailto:[email protected]

Presentations & Public Speaking

Andres Oritz - Paterson & Cooke Australia