ABSTRACT
Questions from Mr. A. Armstrong to Mr. S.E. Olesen
have three questions on the issue of ochre:
How did you map pyrite-rich areas which you then identified as potential ochre problem areas? This is something we have found to be very difficult, particularly the chemical measurement of pyrite content, which we have found to be very variable.
It appears that your concern about ochre arises from the pollution aspect, whereas for most of us here, the problem of ochre arises from the blocking of drainage systems. It appears that in the situations you describe, the iron remains in solution until it leaves the drainage system. It is our experience that this happens only when the drainage water is very acid. Is this the case in the situations you describe?
Have you tried using pine bark to absorb iron? This technique has been used by workers in Scotland with considerable success.
