that's about right. There is a side branch to the stream lower down.
the access is via wiers which over-top when the flow reaches a certain level, and discharges into the outfall.
the overflow was once accomodated by a low-lying area which acted as a surge brake, but uncontrolled infilling of the valley to extend the carpark over the years had removed this rather useful local feature....
''the stopes soared beyond the range of our caplamps' - David Bick...... How times change .... oh, I don't know, I've still got a lamp like that.