Here are experiments with a Conte a Paris charcoal stick, on various surfaces, rough 100% cotton rag and smooth paper and with various layers of dampening to catch the lines. Some have 2B charcoal over this or a touch of colour from Conte crayons. Some are from my recent photos and others outdoors. Above a disused aquaduct across a river, below the view down a gully to the sea.
Here I was trying to capture the lines made by fast flowing water down stream of a weir and the smooth deep welling as it reached the stones. There is a bit of Paynes grey watercolour used to wet the paper.
Here a small sketch of the trees on the opposite side of the railway line, waiting for a train.
The next three are all from the same vantage point on a bridge looking at the trees and woods stretching behind the bank of the canal, in the order of drawing. It shows I have to draw and draw again to see something, which is that the composition is not made by the trees but by the three enclosed fields.
This last was done with stick willow charcoal outdoors and later reworked in brush pen, leaving the charcoal layer intact.
kestrelart 
I enjoy the way you continue to explore your materials. I think the combination of charcoal and brush pen in the last sketch works really well and is something that I would not have thought of to try.
Mmm. I’ve kind of got stuck so experimenting again.
I particularly like the three from the bridge – a really nice use of line. Great experiments!
I like the ethereal effect on the viaduct sketch and on some of the foliage sketches and they contrast well with your final piece which I find effective also. Some productive experiments.
Superb!