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Advances in stonedustingAdvances in stonedusting

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I will talk about and show footage relating to I will talk about and show footage relating to

the basics about Stonedustthe basics about Stonedust

methane and coal dust explosionsmethane and coal dust explosions

why previous wet dusting attempts failedwhy previous wet dusting attempts failed

ACARP project C16014 - Advances in wet slurry dusting ACARP project C16014 - Advances in wet slurry dusting

how the slurry additive process workshow the slurry additive process works

and look at the equipment involved in the processand look at the equipment involved in the process

Some information within this presentation is well known by the Some information within this presentation is well known by the coal industry. It has been included to provide a summary of coal industry. It has been included to provide a summary of how various elements interact. how various elements interact.

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Stone dustStone dust Stone dust or calcium carbonate is used in underground coal mines as Stone dust or calcium carbonate is used in underground coal mines as

a primary inerting agent, in the prevention of coal dust explosions.a primary inerting agent, in the prevention of coal dust explosions.

The application of dry stone dust creates large quantities of airborne The application of dry stone dust creates large quantities of airborne dust along the ventilation circuit, requiring the extraction of inbye dust along the ventilation circuit, requiring the extraction of inbye personnel.personnel.

In a methane explosion, a pressure pulse travels through the In a methane explosion, a pressure pulse travels through the immediate area of the mine.immediate area of the mine.

This wave raises any dust into suspension, both coal and stonedust.This wave raises any dust into suspension, both coal and stonedust.

Areas treated with adequate quantities of stone dust, will render the Areas treated with adequate quantities of stone dust, will render the dust cloud inert and a coal dust explosion will not occur. dust cloud inert and a coal dust explosion will not occur.

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MethaneMethane

The ignition of methane in an underground mine is not common The ignition of methane in an underground mine is not common but does occur.but does occur.

Friction sparks from continuous miner and shearer drum picks Friction sparks from continuous miner and shearer drum picks have provided ignition sources for methane gas.have provided ignition sources for methane gas.

Other potential sources are cable flashes, belt friction, heating Other potential sources are cable flashes, belt friction, heating and open fires.and open fires.

Given the right conditions a methane explosion itself is most Given the right conditions a methane explosion itself is most explosive at 9% general body and has deadly consequences. explosive at 9% general body and has deadly consequences.

The following footage is a weaker explosion that compares to a The following footage is a weaker explosion that compares to a typical 10 metre overdrive allowed to accumulate a methane typical 10 metre overdrive allowed to accumulate a methane concentration of only 7.5%.concentration of only 7.5%.

If an ignition source is present………….If an ignition source is present………….

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7.5% Methane 7.5% Methane ExplosionExplosion

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7.5% Methane 7.5% Methane ExplosionExplosion

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7.5% Methane 7.5% Methane ExplosionExplosion

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Coal dustCoal dust Minimising the make of coal dust and reducing float dust is an Minimising the make of coal dust and reducing float dust is an

ongoing challenge for all coal operations.ongoing challenge for all coal operations.

Areas that were stone dusted once, if left unmaintained, Areas that were stone dusted once, if left unmaintained, accumulate coal dust deposits providing fuel for an explosion to accumulate coal dust deposits providing fuel for an explosion to propagate.propagate.

Only 4-5mm of dry dust will be lifted in a weak methane Only 4-5mm of dry dust will be lifted in a weak methane explosion. The more float dust accumulated, the less of the explosion. The more float dust accumulated, the less of the underlying stone dust will be lifted.underlying stone dust will be lifted.

We saw that a methane explosion creates a fire ball that travels We saw that a methane explosion creates a fire ball that travels behind the shock wave and hits the dust cloud. behind the shock wave and hits the dust cloud.

Insufficient quantities of stonedust in suspension will allow the Insufficient quantities of stonedust in suspension will allow the coal dust to ignite will obvious catastrophic consequences.coal dust to ignite will obvious catastrophic consequences.

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Coal dust explosionCoal dust explosion1 kg1 kg

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Coal dust explosionCoal dust explosion75kg75kg

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Coal dust explosionCoal dust explosion75kg75kg

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Wet stone dustingWet stone dusting Wet dusting was always viewed as an opportunity to help Wet dusting was always viewed as an opportunity to help

overcome reductions in cutting times due to stoppages caused overcome reductions in cutting times due to stoppages caused by stone dusting.by stone dusting.

The onset of 7 day operations compounded the problem and The onset of 7 day operations compounded the problem and attempts were made to apply stone dust as a slurry.attempts were made to apply stone dust as a slurry.

This allowed crews to continue production while wet dusting This allowed crews to continue production while wet dusting was carried out in the ventilation intakes of the panels.was carried out in the ventilation intakes of the panels.

Wet dusting is a process of creating a stone dust / water slurry Wet dusting is a process of creating a stone dust / water slurry and pumping it onto the mines walls.and pumping it onto the mines walls.

The intent was to replicate the conventional dry dusting without The intent was to replicate the conventional dry dusting without the need to withdraw inbye personnel.the need to withdraw inbye personnel.

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Wet stone dustingWet stone dusting

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Why wet dusting does Why wet dusting does not worknot work

The application of wet dusting was proven however the final The application of wet dusting was proven however the final product failed to provide adequate inerting qualities.product failed to provide adequate inerting qualities.

When stone dust comes in contact with water the particles When stone dust comes in contact with water the particles partly dissolve.partly dissolve.

As the slurry dries, the dissolved solution moves between the As the slurry dries, the dissolved solution moves between the stonedust particles forming a bonding bridge that locks the stonedust particles forming a bonding bridge that locks the particles together.particles together.

This is referred to as “The Caking Effect”.This is referred to as “The Caking Effect”.

This caking reduces the amount of stone dust raised into This caking reduces the amount of stone dust raised into suspension, creating enough doubt on its effectiveness as an suspension, creating enough doubt on its effectiveness as an inerting agent.inerting agent.

Inspectors in NSW and Qld rightfully issued directives Inspectors in NSW and Qld rightfully issued directives restricting the use of slurry dusting restricting the use of slurry dusting

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ACARP project C16014ACARP project C16014

Australian Coal Association Research Program (ACARP) contracted Australian Coal Association Research Program (ACARP) contracted Mining Attachments to research and develop a wet slurry treatment Mining Attachments to research and develop a wet slurry treatment process that could overcome the caking effect. process that could overcome the caking effect.

Applied Australia were requested to engineer an additive that would Applied Australia were requested to engineer an additive that would work but had to be end user friendly.work but had to be end user friendly.

In 2006 the additive was ready to be trialled and tested on large scale.In 2006 the additive was ready to be trialled and tested on large scale.

The 3 stage project spanned over two years.The 3 stage project spanned over two years. Surface full scale spray trialsSurface full scale spray trials Underground spraying trialsUnderground spraying trials Full scale explosion testingFull scale explosion testing

Industry monitors were required to assess each stage objectives were Industry monitors were required to assess each stage objectives were achieved, before advancing onto the next.achieved, before advancing onto the next.

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Airo-Dust™ AdditiveAiro-Dust™ Additive Airo-Dust™Airo-Dust™ Additive has been designed with the primary focus of Additive has been designed with the primary focus of

providing a safe product for use in the underground mining providing a safe product for use in the underground mining environmentenvironment

The MSDS outlines all the health and safety requirements.The MSDS outlines all the health and safety requirements. Non-combustible Non-combustible Operators wear standard PPE Classified Non-dangerous goodsClassified Non-dangerous goods Warnings in regards to skin, eyes, inhalation and ingestion are Warnings in regards to skin, eyes, inhalation and ingestion are

similar to those of concentrated household dishwashing similar to those of concentrated household dishwashing detergentdetergent

pH of the additive is between 6-8 (water 7.0 neutral)pH of the additive is between 6-8 (water 7.0 neutral)

The required dosage of 10 litres of additive is required to treat one The required dosage of 10 litres of additive is required to treat one tonne of stone dust.tonne of stone dust.

Airo-Dust™ Additive is a trademark of Illinois Tool Works Inc.

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Surface full scale Surface full scale trialstrials

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Surface full scale Surface full scale trialstrials

Samples were taken during the surface spraying trials and sent Samples were taken during the surface spraying trials and sent for particle size distribution.for particle size distribution.

Results showed little change to the original particle sizes, Results showed little change to the original particle sizes, supporting the anti caking ability of the process. supporting the anti caking ability of the process.

A simulated explosion demonstrated that the treated wet dust A simulated explosion demonstrated that the treated wet dust could be put into suspension.could be put into suspension.

The project moved to Cook Colliery, one of many operations The project moved to Cook Colliery, one of many operations that supported the project. that supported the project.

Mining Attachments fit for purpose equipment was mobilised Mining Attachments fit for purpose equipment was mobilised onsite and the first underground trials began.onsite and the first underground trials began.

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Underground TrialsUnderground Trials

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Underground TrialsUnderground Trials The experience gathered from the 6 months of trials allowed The experience gathered from the 6 months of trials allowed

the necessary time to refine the process with dedicated the necessary time to refine the process with dedicated personnel allowed to focus on achieving the projects aims.personnel allowed to focus on achieving the projects aims.

Industry monitors evaluated the underground trials, operating Industry monitors evaluated the underground trials, operating the equipment and viewing other areas of the mine previously the equipment and viewing other areas of the mine previously dusted using the new slurry additive process.dusted using the new slurry additive process.

The project then moved into the final stages of conducting full The project then moved into the final stages of conducting full scale explosion testing by third parties.scale explosion testing by third parties.

The new slurry additive process was named Airo-Dust.The new slurry additive process was named Airo-Dust.

The CSIR explosion testing facility in Kloppersbos South Africa, The CSIR explosion testing facility in Kloppersbos South Africa, hosted comparative Dry v’s Airo-Dust testing, facilitated by hosted comparative Dry v’s Airo-Dust testing, facilitated by Skillpro Services. Skillpro Services.

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Explosion TestingExplosion Testing The testing facility comprises of a 200m steel pipe tunnel that The testing facility comprises of a 200m steel pipe tunnel that

has a methane mixing station and ignition centre one end and has a methane mixing station and ignition centre one end and the other end is open. the other end is open.

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ExplosionExplosion Testing Testing

Trays were prepared Trays were prepared prior to testing.prior to testing.

Prior to each test Prior to each test explosion, trays were explosion, trays were weighed and secured weighed and secured into the tunnel.into the tunnel.

After the blast the loss After the blast the loss of stone dust from each of stone dust from each tray was recorded.tray was recorded.

High and low speed High and low speed video footage captured video footage captured each blast.each blast.

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Explosion Testing Explosion Testing

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Explosion TestingExplosion Testing

On average 40% more stonedust was lifted from the Airo-Dust On average 40% more stonedust was lifted from the Airo-Dust trays compared to the stonedust lifted from the Dry dust trays.trays compared to the stonedust lifted from the Dry dust trays.

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62

17

54

17

55

20

75

18

10

18

45

82

0

32

18

28

55

14

85

30

35

23

00 3

31

5

14

20

0

500

1000

1500

2000

2500

3000

3500

4000

Explosion test number

Lo

ss o

f sto

ne d

ust

(g)

Dry stone dust trays 3462 1754 1755 2075 1810 1845 820

Slurry additive process trays 3218 2855 1485 3035 2300 3315 1420

6 10 11 12 13 14

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Explosion TestingExplosion Testing On average the depth of dust lifted by the explosions also On average the depth of dust lifted by the explosions also

varied.varied.4-5mm in the case of the Dry dust trays4-5mm in the case of the Dry dust traysin most cases the Airo-Dust trays were empty (30mm)in most cases the Airo-Dust trays were empty (30mm)

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Explosion TestingExplosion Testing

Full details of this project including all the results from the Full details of this project including all the results from the explosion and underground testing can be obtained on line by explosion and underground testing can be obtained on line by visiting visiting

www.acarp.com.auwww.acarp.com.au Project number C16014 Project number C16014

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How the Airo-Dusting How the Airo-Dusting process worksprocess works

Stonedust slurry is made by mixing two parts stonedust with 1 Stonedust slurry is made by mixing two parts stonedust with 1 part water.part water.

The Airo-Dust additive is dosed into the pump out line which The Airo-Dust additive is dosed into the pump out line which provides a protection barrier around the stone dust particles, provides a protection barrier around the stone dust particles, minimising the caking effect.minimising the caking effect.

Air is entrained into the line to create a foam. The product is Air is entrained into the line to create a foam. The product is highly vesicular, trapping millions of tiny air pockets or voids in highly vesicular, trapping millions of tiny air pockets or voids in the product as it dries.the product as it dries.

From the explosion testing it was evident that a methane From the explosion testing it was evident that a methane pressure wave is able to penetrate these voids, smashing pressure wave is able to penetrate these voids, smashing through the surface and raising the stonedust into suspension. through the surface and raising the stonedust into suspension.

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How the Airo-Dusting How the Airo-Dusting process worksprocess works

The equipment consists of a mixing tank and paddle, slurry The equipment consists of a mixing tank and paddle, slurry pumps, additive pumps and the foam generation equipment.pumps, additive pumps and the foam generation equipment.

The system is non adjustable making the process less The system is non adjustable making the process less complicated and simple to use.complicated and simple to use.

The additive is accurately dosed into the pump out line and The additive is accurately dosed into the pump out line and delivers a steady stream of shaving cream like slurry to either a delivers a steady stream of shaving cream like slurry to either a hand held nossel or machine spray bars.hand held nossel or machine spray bars.

Existing equipment can be modified or new custom made Airo-Existing equipment can be modified or new custom made Airo-Dusters can be supplied.Dusters can be supplied.

The Airo-Dust additive is supplied and serviced Australia wide The Airo-Dust additive is supplied and serviced Australia wide by ITW’s Applied Australia or nominated overseas agent.by ITW’s Applied Australia or nominated overseas agent.

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EquipmentEquipment

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EquipmentEquipment

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Getting startedGetting started

A copy of the final ACARP report has been sent to A copy of the final ACARP report has been sent to both NSW and Queensland inspectors for review.both NSW and Queensland inspectors for review.

The NSW DPI have assembled a review committee The NSW DPI have assembled a review committee to firstly review the ACARP report and secondly to firstly review the ACARP report and secondly participate in the initial underground trials in NSW.participate in the initial underground trials in NSW.

This will allow the Airo-Dusting process to be viewed This will allow the Airo-Dusting process to be viewed from both a technical and practical perspective.from both a technical and practical perspective.

Operations can now make application to the NSW Operations can now make application to the NSW DPI to use the Airo-Dusting process underground.DPI to use the Airo-Dusting process underground.

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Current participating Current participating sitessites

Grasstree MineGrasstree Mine 1 x existing wet duster modified into an Airo-Duster1 x existing wet duster modified into an Airo-Duster 2 x new Airo-dusters2 x new Airo-dusters

Greenside Colliery (South Africa)Greenside Colliery (South Africa) 1 x new Airo-Duster1 x new Airo-Duster

North GoonyellaNorth Goonyella 1 x Hire Airo-Duster1 x Hire Airo-Duster

Centennial Coal (Mandalong, Clarence, Springvale)Centennial Coal (Mandalong, Clarence, Springvale) DPI application pendingDPI application pending

Vale (Integra Coal)Vale (Integra Coal) DPI application pendingDPI application pending

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Airo-DustingAiro-Dusting