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RPS Energy LtdExplosives Engineering

Services

UXO Below:Mitigating Marine UXO Risk

Presented byVictoria Phillips

■ “ To deliver an overview of Unexploded Ordnance (UXO) in the marine environment, the Risks posed

■ during Engineering works, and to consider appropriate strategies for mitigations”

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Aim

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What is Unexploded Ordnance?

United Nations Definition

“Unexploded Ordnance (UXO) are explosive

munitions, which have not yet been set off. UXO may already have been fired,

dropped, or launched, but it has failed to detonate as

intended”.

Other DefinitionsAXO: Abandoned Explosive Ordnance. Explosive ordnance that has not been used during an armed conflict, that has been left behind or dumped by a party to an armed conflict, and which is no longer under control of the party that left it behind or dumped it. Abandoned explosive ordnance may or may not have been primed, fuzed armed or otherwise prepared for use.

ERW: Explosive Remnants of War. Unexploded Ordnance (UXO) and Abandoned Explosive Ordnance (AXO).

MEC: Munitions & Explosives of Concern

From: IMAS 04.10 – Glossary of mine action terms, definitions and abbreviations.

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Contamination Sources

- Conflict / Battle Areas

- Weapons Testing /Training

- Bombing & Firing Ranges

- Aircraft Wrecks

- Ship Wrecks

- Coastal Batteries

- Sea Dumped Munitions & Scuttled Vessels

Numerous historical activities across the world have left a legacy of UXO contamination:

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Conflict – WWII North Sea

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Conflict – WWII North Sea

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Artillery & Bombing Ranges - UK

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Aircraft Wrecks – South Pacific

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Ship Wrecks-Thames Estuary

The Richard Montgomery

- Loaded with 7000 tons of explosives

- If the munitions detonated the consequences could be catastrophic

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Dumped Munitions

- Army secret ocean-dumping program - from 1944 to 1970

- Nerve and mustard gas agent, Chemical filled bombs, landmines, rockets, Radioactive waste

- Operation CHASE (Cut Holes & Sink Em)

- Army cannot say exactly where all weapons were dumped from WWII to 1970

- During WWI munitions were not to be brought into the harbour and were dumped prior to entry

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Ordnance Variants- Air Delivered Bombs

- Land Service Ammunition

- Projectiles

- Small Arms Ammunition

- Land Mines

- Rockets / Missiles

-Sea Mines

-Torpedoes

-Depth Charges

-Chemical Warfare Material

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Air Delivered Bombs

Left: High Explosive Bombs

Below Left: 1000lb HE Bomb

Below Right: 8.5lb Practice Bomb

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Land Service Ammunition

Above: Hand Grenades

Top Left: Bazooka

Bottom Left: 3” Mortar

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Projectiles- Used in the Persian Gulf

155mm French

155mm USSR WWI White Phos

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Landmines

Above: British Mk2 AT Mine

Right: VS 69 Bounding Mine

Torpedoes Naval Artillery Ammo

Naval Weapons

Limpet Mines WWII Buoyant MineGerman Ground Mine

Depth Charges

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Chemical Warfare Material (CWM)

Above: US Munitions dumping program

Top Middle: UK chemical weapons dumping

Bottom Right: US disposal ship

Top Right : Liven Projector WWI

HE ordnance does not generally spontaneously explode. Unfuzed HE requires significant energy to induce initiation.Potential initiation depends on ordnance fuzing and investigation activity. Examples are:■ Drill / piling impact on bomb fuze pocket, which has build up of picric acid crystals■ Cutter dredger strikes percussion fuze on a mortar■ Seabed Plough strikes a sensitive munition

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UXO Risks - Initiation

Water can have a suppressive effect on explosive events

Therefore the safety/danger distances will be significantly reduced in the event of an underwater detonation, dependant on the depth of water.

This affords some protection to personnel and equipment.

This protection is lost once items of ordnance are brought to the surface.

Underwater Explosions

Explosion Underwater Effects

Water is a different consistency and produces extremely effective tamping or cushioning effect

To achieve Target Damage at a distance larger charge weights are used in most underwater weapons.

BUBBLE PULSE EFFECT is often used in mines to advantage.

Differ to explosions in air because:

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Torpedo Testing

Torpedo wearhead - 1200 LB TNT. The warhead detonates below the keel, as opposed to striking it directly. The resulting pressure wave of the explosion "lifts" the ship and can break its keel in the process. As the ship "settles" it is then hit again as the explosion itself rips through the area of the blast.

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UXO Assessment & Mitigation

Desk Based Risk Assessment

Risk Mitigation Strategy

Sign off

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- If possible should be undertaken at the planning Stage- Site scope

- Intertidal &/or Offshore- Water Depths & Seabed Type/ Mobility

- Site History

- Ordnance Records- Detailed Historical Search- Hydrographical Mapping- Accessing Archived Data

- Identify Dumping locations- Weapon Characteristics (NEQ, Fuzing )

- Understanding of Site works- Methods of installation

- Identify Hazard Levels - Identify Appropriate Mitigation

Desk Based Assessment

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Mitigation Strategy

Proactive Measures:- Avoidance- Detection (survey)- Investigation- Disposal

Reactive Measures:- Safety Briefings- UXO Supervision & Management Plans- Screening

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Sub Bottom Profile

Detection - Geophysical Survey

Magnetometry / EM Side Scan Sonar

www.rpsuxo.com

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Geophysical Techniques- Survey Considerations

Ordnance variations:

- ferrous / non-ferrous

- size / weight / shape

Burial/Penetration depths:

- is the ordnance on the sea bed or buried

Sea bed composition

Sediment mobility

Water depths

Detection capability:

- Fish/Array Height

- Line spacing

Positional accuracy

- GPS / USBL

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Anomaly Investigation

Divers – Hand Held Detectors,Air Lifts & Tactile Search

ROV’s – TSS / SmartSearch, Dredge Pumps / Sonar

www.rpsuxo.com

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Disposal

Diver attaching lifting bag

Towing the mine/UXO

Towing the mine/UXO

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Thank you for attending

Any Questions?