I worked at Binley Colliery from 1949 to 1954, it was my first job! In the 1940s, I believe, a drift was driven at 1 in 1 down from the pitbottom - about 300 yards from the shafts. It reached the coal measures at about 2000 feet deep. I don't think it was in the thick doal, but was in the seams that make up the Warwickshire Thick coal at Coventry Colliery. The seams were Two Yard, Ell, Ryder and Six feet.
Regards Peter Glenn.