Historic Shafts and Rescue

Background

 The American author and activist Helen Keller told us that a lush carpet of pine needles on spongy grass is more welcome than the most luxurious Persian rug, but what when that Persian rug disappears with a rush of cold air and the unnerving echo of a scream?

 Far-fetched? Throughout the history of the British Isles people have looked below ground believing in ‘something’ mystical that entices and encourages them to dig for riches, dig for warmth, dig for food – thousands of years of digging forgotten!

The UK Coal Authority has 170,000 records of coal mine shafts and maps going back as far as 1750, but mine owners were not compelled to notify the state of their mine workings before 1872 (1).

"March 2020, Beacon, Camborne, Cornwall – Property damage due to a hole appearing in the ground after a tree falls in bad weather leading to the ground collapsing into 200-year-old mine workings" (2)

The scenario

Envisage a person taking a leisurely walk with their dog oblivious to the bowl-shaped indentation they just stood in. Fellow walkers are horrified at seeing the ground open ‘swallowing’ their companion. 

Why has this happened?

 Historic test pits and shafts were often temporary, and varied in terms of size, depth, and complexity. Few lived up to expectation, so prospectors would simply apply wooden boards and lightly fill them with earth and move on.

Erosion, rotten wood, and stealth!

 As the ground fell away the shaft started to fall in on itself, affected by gravity, friction, directional forces, and changes in air pressure.

 The boards have stood the test of time, but no longer. They have broken and fallen destabilising the ground and sides of the shaft creating loose debris and falling objects, which are landing on the walker.

The dog? She scampered away, but what about the walker?

They could have had a clean fall to the bottom but depending on the width and depth of the shaft they likely made contact with the sides on the way down – your ground is well and truly unstable.

The blunt, twisting and impact forces applied to the dog walker irrespective of distance fallen have now conjoined with the environment to create a potentially challenging scenario.

 Confusion is in abundance and onlookers cannot articulate what they have just witnessed. They attempt to get to the edge and peer down into the deep, cold lonely relic of the industrial past.

 Operating mines have ventilation and extraction, which are designed to ensure that breathable air does not drop below 19%. When all those systems are removed, mother nature takes over.

Oxygen deficiency is not the only worry, gasses of decomposition, such as Hydrogen Sulphide (H2S) are heavily toxic in high concentrations. 

March, 2021 – Quad bike and its rider fall into a 60ft deep sinkhole. Could be mining or nature, but the need is the same – rescue (4)

Considerations for hazard control (non-exhaustive):

ACCESS - prevent unauthorised vehicle movements, which could destabilise or overload the surface. The shaft could be interacting with roadways or other structures, that cannot be seen, but could be equally vulnerable.

GROUND MOVEMENT – is the ground cracked, loose, moving, making sounds? Co-operate with others, agree an exclusion zone.

SPREAD THE LOAD – don’t focus a load in one area, watch out for ‘kit dumps’ and their location. Look at equipment set up; does it rely on the edges of the shaft for support? Consider Artificial High Directional Anchors.

 WORK AT HEIGHT – yes even below ground level. Management of people, equipment, fall arrest and or fall restraint, anchor points, planning and supervision.

 ENVIRONMENTAL – Mine gases are notorious for causing illness and death. Old mining environments without their ventilation can build up harmful gases. Safely checking and monitoring gas levels is vitally important for safety – NO SMOKING!

ATMOSPHERIC PRESSURE – high and low pressure can have an impact on gases within strata.

 DRONE – are blades protected, is the device intrinsically safe (explosive gas), air turbulence and loss of GPS could affect control. Good use of a camera to view without deploying people.

 WATER – consider is the casualty treading water or are they face down? Water is powerful it may be flowing, rising, or washing sides away undermining the structure.

 ENTANGLEMENT – there can be any number of obstructions under the water.

 FALLING OBJECTS – cleanliness is next to godliness. All that Gucci gear needs to be secured or tethered. Do not make their day worse by dropping it on them.

 STRATA – avoid contact with and bouncing of the sides while abseiling or lowering equipment. Lower down the middle to reduce risk of falling debris, or collapse.

 SHAFT INTRUSION – depending on the age of the shaft there may be remnants of its structure. Be aware of snagging, exposed bolts, iron workings, cracked or exposed pipework, wood, splinters, bagging, and cable.

EQUIPMENT CONTROL – anchors, safety devices, stretchers, bags all have the potential to ‘strike’ the shaft if they fall or get away from you.

Conclusion

 Scene safety is essential for all - Mine workings must be respected. Following JESIP principles will help manage the incident.  Co-locating with colleagues near the incident and enabling lines of communication will aid decision making and risk assessment (5).

 Sharing these will enable a safe working strategy to develop, which hopefully culminates in a successful outcome for all involved.

 References:

1.      https://www.gov.uk/government/publications/coal-mining-data-mine-entries/mine-entry-metadata

2.      https://www.bbc.co.uk/news/uk-england-cornwall-25942266

3.      https://www.bbc.co.uk/news/uk-scotland-glasgow-west-15739209

4.      https://www.itv.com/news/granada/2021-03-05/lucky-escape-for-quad-biker-who-fell-down-60ft-sinkhole-in-cumbria

5.     https://www.jesip.org.uk/home