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Hi Team,

I sent an email to CXY about a week ago, but have not had any response. So hopefully some of you might be able to answer these questions. Thanks in advance.

Dear Dr Len Walker,

I have a few questions, that I was hoping you could please answer for me. I have read various articles about the process, but am unsure about a couple of areas.

1. If the coal is ignited underground, how do you contain the spread of the fire?
2. If the spread of the fire is contained simply because of the coal being compacted underground, what about cracks that the fire may creep into?
3. If the fire can get through via cracks, is this fire now running out of control?
4. Because we don't have fences underground, how can you control the burn so that it does not spread into someone else's land? I guess it is a bit like drilling for oil, and drill your hole in your area deeper than your neighbours oil deposit and let gravity take care of the rest.
5. As the coal burns away, this of course will leave a hole underground (a bit like a cave), can the ground become unstable?
6. As the hole/cave becomes larger, does the coal burn faster, or is this managed by how much oxygen is pumped into the bed?
7. I have read some people say the process could contaminate the water. When you extract the gas produced, does it come up through a water tight tube?
8. If it does have to come up through a water table, how do you stop the water from running down the hole drilled to extract the gas and putting out the fire?

Cheers