Aye,that's right Peter.The length of the Manriding tunnel after the bend was driven through the old T'bone and Wigan 4ft workings on the downthrow side of the "60yd fault".This used to be the boundary of the pit until the late 1950's when the "new" Loco Tunnel was driven through it as part of the pit's development into the South Area. I can't recall any stories of oil seepages where you say but they would,as I say,be coming from the Wigan 4ft which has a reputation for oil throughout Lancs and at Golborne is about 15-20 yds above the T'bone.
The incline as you call it would be the "1 in 3".This again was in the old workings of the T'bone/Wigan 4ft and served the purpose of a dual return for the pit.As with any old workings there's always water involved and what you heard would carry on running downhill into the old workings below the manrider tunnel to be pumped out at the old pump station near the bend you mention.
As for the water in C9,that would be coming from the old C7 face to the rise and making it's way there through a sandstone bed about 10yds above the Crombouke seam.
Incidentally,the "old C7 face" was just starting to be developed in 1972 when I was starting my mining career and was the first working I went to down Golborne when I went to help set out C7 Return.The 2nd place I went to was on C5 face,which was right under the East Lancs,and where the joke used to be that when it was quiet, you could hear the Scammell trucks going past.