Coal used for this process is called steaming coal. In 2008 77% of the electricity generated in Australia was produced by coal fired power stations (includes black and brown coals). Some types of black coal are suitable for coke-making.
These symptoms may occur in the back, leg and down to the foot. The most common nerve irritation originating from the lumbar spine is Sciatica. This is an irritation of the sciatic nerve, which can produce pain, numbness, and weakness down the leg along the areas innervated by the sciatic nerve.
I also have sciatic nerve damage. I was told to see a chiropractor or acupuncturist and to do regular stretches to strengthen my back. You MUST follow the chiropractors instructions all the time to reduce your pain and help the sciatic nerve to heal. It can take 3 months or more to feel better depending on the severity.