...supporting the mine structure at Winsford
Since 1844 rock salt has been extracted via the room and pillar method of mining, which means that pillars of rock salt are left behind to support the roof. It is such an effective method that we don't have to use roof bolting, metal mesh or pillar supports.
Typically the 'rooms' are 20m wide and 8m high with pillars of 20m². These now make up the connecting tunnels. There are now over 137 miles of them!
Rock research holds up
In the 19th and early 20th Century mining was high with almost 90% of the salt being extracted. As rock salt tends to move over time, much research in the 1950s was carried out to establish the extraction rate of between 68 and 75%.
This research was carried out by the Mining Department at Newcastle University. They investigated rock mechanics and, as a result, developed new instruments to measure rock creep and strata deformation. The information the research provided, together with other measurements, then gave us the knowledge to determine extraction rates for new areas of mining.
