mark macabe - ge industrea mining technology

13th Longwall Conference October 2014

Reduction of Outbursts Through Directional Drilling

Mark MacCabe – Product Manager - Drill Guidance Systems GE Industrea Mining Technology, GE Mining

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History – 1902 (Stuart Piggin and Henry Lee, 1992. “The Mt Kembla Disaster”)

On the 31st of July, 1902 at 14:03, there was an explosion at Mt. Kembla colliery which killed 96 men and boys.

The sound of the explosion could be heard in Wollongong, some 11 kilometres away. At the end of the day 33 women were widows and 120 children were fatherless.

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Rescue Efforts

The hundreds of rescuers were headed by former Keira Mine manager and ex-mayor of Wollongong, Major Henry Osborne MacCabe who had played a vital part in rescue efforts at the Bulli Mine disaster in 1887 which killed 81 miners.

MacCabe, (the eldest son of Francis Peter MacCabe), and Nightshift Deputy, William McMurray were to lose their own lives during the rescue effort to the effect of "overpowering fumes", adding 2 more deaths to the 94 miners.

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Royal Commission

The first official inquiry into the disaster returned a conclusion that Mt. Kembla Mine was both gassy and dusty and that the men "came to their death from carbon monoxide poisoning produced by an explosion of fire-damp ignited by the naked lights in use in the mine, and accelerated by a series of coal-dust explosions.”

A Royal Commission into the disaster held in March, April and May of 1903, confirmed the gas and coal-dust theory accepted by the earlier Coroner’s Jury.

Rather than holding any individual official of the Mt. Kembla Company responsible, the Commission stated that only the substitution of safety lamps for naked lights could have saved the lives of the ninety-six victims.

Outbursts

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What is an Outburst? An ejection of coal and a large volume of noxious or flammable gas from a working face area.

It is associated with an abnormally high release of gas, the volume of which is significantly higher than can be accounted for by the normal gas pressure and content of the coal displaced.

The event occurs over a short period which may extend up to several seconds and will often feature the existence of a remnant conical cavity in the coal.

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Bulli Seam Outbursts (Dr Chris Harvey, R. N. Singh, 1998. “A review of fatal outburst incidents in the Bulli Seam”)

• First reported outburst: Metropolitan Colliery; 30th September 1895

• First fatal outburst: Metropolitan Colliery; 10th June 1896

• Largest outburst: Tahmoor Colliery; 24th June 1985, 400 tonne of coal and 4,500 m3 CO2 (estimated)

• Most Number of outbursts; West Cliff Colliery: over 250 recorded incidents including the only recorded outburst off a Longwall face.

• Last fatal Outburst: West Cliff Colliery; 25th January 1994 - Malcolm Leslie Butt was killed by an outburst of coal and Carbon Dioxide gas.

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Post 1991 Fatalities

A number of working groups were established to: • Understand the Outburst mechanisms. • Define gas content measurement. • Understand gas drainage techniques. • Develop management plan guidelines

• Research work especially by Dr. Ripu Lama CSIRO Probably the most significant single conclusion from Dr Lama’s work was,

“if you remove sufficient of the gas from the coal, an outburst cannot occur”.

A Steering Committee convened with representatives of mining companies & unions.

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Action

• Following the fatal outburst at West Cliff Colliery in 1994 the need for Management Plans and Compliance to specified

Threshold Values were imposed. • 11th May 1994 all Bulli seam mines were issued with a notice

under Section 63 of the Coal Mines Regulation Act 1982 Implement Outburst Management Plans (OMP’s) Take Gas Samples in advance of all Development Roadways Impose Threshold Level for “safe mining” Require training in Outburst warning signs

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Dramatic Results

(Dr Chris Harvey, R. N. Singh, 1998. “A review of fatal outburst incidents in the Bulli Seam”)

I.S. Survey Tool Development The following Survey Tools are Approved for Safe Use in Gassy Underground Coal Mines

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Eastman Single Shot Camera

Film with developed image

• Earliest technique, from 1940’s • Mainly Rotary Drilling, some Directional Drilling • 30m Survey spacing (typ.) • Manual operation or pump down & Wireline retrieval • Develop film then interpret and record survey data.

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Manual Survey Record

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DDM Directional Drill Monitor

• Introduced early 1990’s • Directional Drilling • 6m Survey spacing (typ.) • MWD operation • Sound wave Data transmission • Survey time approx. 2 mins • Data stored for download

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MECCA Drill Rods Modular Electrically Connected Cable Assembly

Developed in 1994 By Advanced Mining Technologies

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DDM – MECCA DDM – Modular Electrically Connected Cable Assembly

• Produced 1995 • Directional Drilling • 6m Survey spacing (typ.) • MWD operation • I.S. Data transmission • Survey time approx. 5 secs. • Data stored for download

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DGS Drill Guidance System

• Produced 1999 • Directional Drilling • 6m Survey spacing (typ.) • MWD operation • I.S. Data transmission • Survey time approx. 5 secs. • Data stored for download • L/R & U/D Graphs & CTF • Full Diagnostics • Keyboard control

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DGS Touch Drill Guidance System (with Touchscreen)

• Produced 2011 • Directional Drilling • 6m Survey spacing (typ.) • MWD operation • I.S. Data transmission • Survey time approx. 5 secs. • Data stored for download • L/R & U/D Graphs & CTF • Full Diagnostics • Touch Screen control

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DGS Touch - Graphic Display

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Survey Time Comparison Su

rvey

Tim

e

Hole Length

DDM Acoustic

2 mins

DDM-MECCA, DGS & DGS Touch

5 secs

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Precision Engineering

Inseam Directional Drill Rigs The following Drill Rigs are Approved for Safe Use in Gassy Underground Coal Mines

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Universal Drill Rigs B20 (JKS Boyles’ agent in Australia)

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Boart Longyear LMC90 (Underground at Metropolitan Colliery)

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GE Industrea IDS90 Crawler

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GE Industrea UDS90 Modular

Underground In Seam (UIS) Directional Drilling

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Downhole motor Assembly

1.25 Deg

Drill rod Diameter = 69.9 mm

Drill Bit Diameter = 96.1 mm

Downhole Motor

Overall Downhole Motor Assembly Length = 3 metres

Bent Sub Drill Bit

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Downhole Motor & Bit

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Hole Methodology

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Hole Examples - Australia

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Hole Examples - China

Gas Drainage

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Routine gas content testing is the prime means of protection against instantaneous outbursts of coal and gas. In applying gas content results to mining, the following elements are important:

• The gas content threshold

• The area around a roadway to which the threshold applies (the “barrier”)

• Taking sufficient samples and in the right localities

• Minimising the chances that an error has been made in the gas content test

Gas content thresholds were initially determined for the Bulli seam on the New South Wales South Coast Lama (1995).

They have been extended to the Hunter Valley, Bowen Basin and New Zealand (Mt Davy Mine) using GeoGAS’s Desorption Rate Index (DRI) approach (Williams and Weissman 1995, Williams 1997).

Gas Drainage – Introduction Ray Williams, 2002. Gas Content Testing For Outburst Management Compliance

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Sample Locations

Gate roads are normally developed after cross block drilling and gas drainage. The regions where gas drainage is least effective is toward the ends of boreholes. Here, gas recharge results in a reduction in gas drainage efficiency toward the end of boreholes as evidenced in gas reservoir modelling and corroborated to varying degrees, by field measurements.

While it is generally accepted that cores need to be taken in areas of suspected worst gas drainage, understanding the borehole end-hole-effect provides a basis for the sample location rationale. In addition to the direct use of core results for compliance, they should significantly aid in the better design of borehole length and spacing combinations.

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Gas Drainage - Canisters

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Gas Drainage Example - Australia

A B

C

D

E

B

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Planned Drilling Actual Drilling

Gas Drainage Example - China

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Summary (Hanes J., 1998. Inseam Drilling for Gas and Exploration - Recent advances)

In-seam drilling is conducted mainly to drain coal of gas and/or water

prior to development or extraction. The requirements of inseam drilling for gas drainage have mainly

surpassed the technical limits of rotary drilling and are mainly being addressed by guided down hole motor drilling, albeit at a higher cost.

There is an increasing application of in-seam drilling to detect geological structures or other hazards or their absence in advance of mining to reduce the risks of underground mining.

Close collaboration between miners, drillers, geologists, researchers and suppliers over the last few years has seen many advances made to improve the accuracy and reliability of inseam drilling.

With such developments will come closer control over the ventilation and safety of future mining under deep gassy conditions, but not without costs.

Bibliography

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Bibliography Piggin S., Lee H., 1992. The Mt Kembla Disaster. Sydney University Press in association with Oxford University Press Australia. MacCabe M., 2011. The Man Behind The Corner Sheldon B., McShane M., 1999. www.illawarracoal.com/mtkembladisaster.htm Mt Kembla Colliery Gas Explosion – 1902 Harvey C. Dr., Singh R. N., 1998. A review of fatal outburst incidents in the Bulli Seam Harvey C. Dr., 2002. History Of Outbursts In Australia And Current Management Controls. 2002 Coal Operators’ Conference

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Bibliography…cont’d

Hanes J., 1998. Inseam Drilling for Gas and Exploration - Recent advances

Hanes J., 2002. Current In-seam Drilling Techniques

Williams R.J., 2008. Application of Gas Content Test Data to the Evaluation of Gas Emission and Hazards During Longwall Development and Extraction.

Williams R.J., 1997. Definition Of Outburst Threshold Limits From Core Testing

Williams R.J., 2002. Gas Content Testing For Outburst Management Compliance

Department of Mineral Resources (NSW), Document No. MDG 1004 – Outburst Mining Guidelines (July 1995).

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THANK YOU.