Andy Smith
MIne-action specialist
 

Excavation

 

What follows is the PowerPoint presentation named "Excavating?", formatted as a scrolling webpage.

Humanitarian Demining

Part 4: Excavating

 

Manual demining relies first on detecting a suspect area. This may be done with a metal-detector, a dog, because of a gap in a pattern of known mines or because there are reliable reports that a device is present.

The following are pictures of deminers at work. None of them were taken during demonstrations or are "posed".

Excavation can be broken into three parts, usually performed as a cycle several times in any one excavation:.

      • - Prodding - with a thin probe to loosen ground
      • - Picking/scraping - with a broad tool that may be twisted to break up the ground.
      • - Digging with a trowel-tool to remove soft or loosened spoil.

Many demining groups only issue one tool with which to carry out all three stages - frequently a bayonet.

The picture shows a deminer in the Balkans. Most deminers work in a similar position. He probes to loosen the ground and feel for obstructions, then scoops the loose spoil away. The ground in this area is soft and the anticipated mines would be shallow, but the deminer still uses both hands to push his probe into the ground.

This is because of ground friction on the blade of the tool. The tool should always be inserted at an angle of 30 degrees (or less) to the ground. If you push a probe 14cm into the ground at this angle, the point will only be 7cm deep, so the "search" depth is shallow.

To push the tool 14cm into the ground usually takes more force than is safe, and requires the use of both hands.

The long-handled probe allows two-handed pushing. Clearance with just a probe generally means clearance to a depth of 5cm or less.

When using a metal-detector, the safest way to explore the detector-reading is to excavate.

A marker is placed at the closest point of the reading. Sometimes another marker is placed in what seems to be the centre of the reading. Then the deminer moves back at least 20cm and starts a downward sloping excavation. Usually the area will be prodded first, then loosened spoil is removed. I recommend using anvil root-secateurs to cut any roots encountered, and a long trowel to remove the loose spoil. By prodding into the face of the excavation (working from the bottom upwards) , then removing the spoil before prodding again, the deminer should strike the mine on its side rather than on its pressure plate and so should "feel" where it is.

The hand closest to the ground may be the left or the right hand.

This deminer is leaning forward to prod - and with his visor raised so that he can see clearly. (Sadly, the condition of many visors means that raising the visor at the most dangerous time is common.)

This man is prodding with a needle probe. He uses his left hand to guide the probe.

This deminer in Cambodia is digging with a wood chisel. The deminer is not wearing a huge hat - it is a cotton towel to shield his head from the sun.

This picture shows a deminer in Afghanistan. He loosens the ground by twisting a short bayonet, then scoops the loose spoil away with his left hand.

In this picture the length of the bayonet is clearly visible. Bayonets get shorter over time - as they get blunt and are sharpened using a grind-wheel.

Notice the locally made trowel this man is using to start his excavation.

Notice this locally made prodder in Afghanistan. Its broad blade means that it is also used as a scraping tool or trowel. The deminer wears a glove on his left hand because he scoops loosened spoil away with that hand - and the glove prevents scratches.

This is also in Afghanistan - where the ground is so hard that the deminer starts his excavation using a pick. This pick is more like a thin axe on a long stick. Picks in Afghanistan vary.

This is a more conventional double headed pick on a thin wooden shaft. The deminer swings in from the side to "shave" away the face of the excavation and has often continued right up to the mine without changing tools. Unsurprisingly, there have been frequent accidents when using a pick-axe.

This deminer in Cambodia has a long-handled trowel but is using it in a way that could cost him both hands.

This deminer in Angola is excavating with a very short trowel. The short tool encourages him to lean forward right over any possible detonation.

Excavating with a short, locally-made tool. The tool is so short that his fingers would be almost on top of any detonation.

This deminer in Angola is cutting a root with secateurs. Both hands are very close to the ground.

This is in Cambodia where a deminer is cutting roots with a knife. Both hands are very close to the ground.

Some groups only issue one tool for investigating metal-detector readings. Usually the single tool is a bayonet or thin probe, but sometimes it is a trowel. Clearly, it is not possible to move spoil aside with a thin probe, and it is not possible to probe with a trowel, so the safety of an excavation is compromised. When that happens, severe injuries that require surgical amputation occur.

The user's hands only have to be 30cm away from the blast to avoid the worst of these injuries.

The best way to achieve distance from an excavation is to use long handled rakes designed for the purpose.