Mynyddislwyn is actually a mountain in between two valleys.
It seperates the Sirhowy valley from Abercarn, Cwmcarn and surrounding areas.
I live in the middle of the Sirhowy Valley at a place called YNYSDDU.That is between Crosskeys and Pontllanfraith. One road into the valley and one road out!!!
There were many collieries around here for many years, but they have now all gone. Within about a five mile radius they were about 20 mines or so. If you can be a bit more specific I may be able to help you.
The place you named, Fleur de Lys is about 4-5 miles away and is a small village. It is very near to Blackwood and on the edge of Cefn Fforest(my inlaws live there) so again I could help.
Please feel free to contact me on: email@example.com