Improving Longwall Hydraulics –Kestrel Coal Case StudyTristan Lovell

22 October 2012

Summary

This presentation will cover:

• Kestrel Location

• Longwall Equipment

• A brief history of Kestrels Longwall Hydraulics

• Improvements

• Lessons Learnt

Kestrel Mine in production

since 2002

Kestrel Mine Extension

production forecast in 2013

Operations are adjacent to

agricultural land use

22 October 2012

Longwall Equipment

Equipment Kestrel Mine

Shearer Cat EL3000

Roof supports 146 x 860t + PM4

AFC 855kw CST P drive M-gate

855kw CST KP drive T-gate

Pump station SES (900 L/min) + Kamat (900 L/min)

Crusher 250 kw drive unit

BSL 400 kw drive unit

Monorail Macquarie system

Nameplate capacity 2500 tonnes per hour

Kestrels Longwall Hydraulics – A brief history

• The Longwall Shield hydraulic arrangement at Kestrel Mine consisted of a

single pump station arrangement being fed by an underground mix of oil

and water to create an emulsion.

• The system used a mechanical mix system and back up venturi style

mixing unit to siphon oil and water together

• The system also utilised an oil pod arrangement that required replenishing

every second or third day.

• This system of supply was logistically inefficient.

Tanker fills

bulk surface

tank with oil

Supply team

fill oil pod on

surface and

transport

underground

Empty pod

swapped with

full pod and

transported to

surface

Kestrels Longwall Hydraulics – A brief history

• The water supply used for Kestrels emulsion mix began as filtered raw

water:

• This system performed adequately for a number of years….

Surface filtration

system

Underground sand

filter pod

Mixed with

oil

Offsite

supply

22 October 2012

Kestrels Longwall Hydraulics – A brief history

• During the 2008 flood event in the Emerald region sediment build-up in

the local water supply increased dramatically.

• The raw water filtration system was inadequate to keep up.

Valve damage from contamination.Raw water filters often overloaded & by passed

Improving the system

• During this flood event – the hydraulic performance of the longwall shields

became diminished and a spotlight on the system was shone.

• An assessment of the system was undertaken and a number of key areas

for improvement were identified:

• Water quality – absolute and minimal variability

• Fluid control – a higher level of consistent ratio Water to oil mix was

required

• Environmental Quality – the impact of the hydraulic component of

the mixed product needed be minimised.

22 October 2012

Improved Water quality

After the flood event of 2008, a dedicated water line run from the onsite

water treatment plant was installed into the underground Longwall panel.

By taking water directly from the water treatment plant, variability in water

quality could be eliminated and high quality clean water could be used to

mix emulsion.

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Usag

e R

ate

(L

/m)

Months

Emulsion Usage Rate

FLOOD EVENT INTRODUCTION OF

TREATED WATER

CLEANING SYSTEM

22 October 2012

Improved Fluid Control

At the beginning of 2010, a Q-mix surface mixing plant was installed.

With the underground mechanical mix on demand system, concentration would vary by up to

75% of target concentration.

The Q-mix PLC controlled system reliably maintains +/- 0.1% accuracy, continuously monitors

the fluids other essential properties, and ensures that the longwall is delivered the highest

quality fluid at all times.

Mixing plant control module Kestrel Citect diagram

22 October 2012

Improvement: Synthetic fluid

Converted to new technology synthetic fluid, Quintolubric with:

• Increased corrosion protection

• Higher lubricity

• Cleaner operation

• Lower operating concentration (2%)

• Higher safety

• Lower environmental impact

Improved Environmental Footprint

No mineral oil from hydraulic leaks

Biodegradable 97% in 28 days

Reduced Chemical Oxygen demand (COD) by 75%

Reduced risk of impact on ground waters

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Improved Cleanliness 1. Reduce filter usage

2. Increase life of HP pumps and reduce seal gland replacement

3. Expand solenoid valve life

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Improved filtration

Emulsion Fluid

Filter

Particles

Synthetic fluid

Oil Particles

Increased Contamination capacity & lifetime• Less oily residues

• No water soap residues

• No antifoam residues

• Higher efficiency through thicker caking

Profile filter use over time

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Nu

mb

er

of

Filte

rs U

sed

Week

Almost complete elimination of

profile filter usage over 4 years

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Improved Pump station performance

Decrease Contamination

• No mineral oil to soften seals

• No particles agglomeration to wear plunger

• No aeration to expand and destroy plunger surface

• Improved pump efficiency through less foaming

Lower Maintenance cost

• Seals change out time decrease by 2 times

• Extend ceramic plunger life

Productivity Improvement

• To replace damage parts for the high pressure pumps

22 October 2012

Improved solenoid performance

Decrease Contamination

• No fatty acid soaps to block the solenoid valves

• No antifoam blocking the solenoids

Lower Maintenance cost

• Solenoid change out decrease significantly

Productivity Improvement

• To replace solenoids

Solenoid Usage Over Time

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Nu

mb

er

of

So

len

oid

s U

sed

Week

Downward trend of solenoid

usage over 4 years

Lessons Learnt

• The longwall shield hydraulic system is key to the assets health

• A set and forget approach to shield fluid systems will eventually lead to significant loss in productivity and an increase in material cost

• Active measurement and management of the use of hydraulic fluid will ensure an operation understands its systems health

• Increased performance, environmental improvement and cost reduction do live happily together – efficient solutions can and will yield all three

• An active interest in the technology advances available will ensure even aging assets can keep up with the latest standards and perform well.