A laboratory test program has been carried out to evaluate and compare methods to
predict the formation of acid mine drainage (AMD) in mine wastes, to evaluate the
reliability of the methods in predicting actual field behaviour at minesites, and to
recommend prediction methods most suitable ‘ for laboratory and field use. Methods
evaluated included static tests and kinetic tests. The following documented prediction
procedures were studied:
- B.C. Research Initial Test
- Acid Base Accounting
- Alkaline Production Potential : Sulphur Ratio Test
- Hydrogen Peroxide Test for Pyrite Estimation
- B.C. Research Confirmation Test
- Humidity Cell Test
- Shake Flask Weathering Test
- Soxhlet Extraction Test
- Manometric Carbonate Pressure Analysis
In addition, three other tests, modified from the original procedure or developed during
the study were evaluated
- Modified Acid Base Accounting
- Net Acid Production Test
- Modified Biological Confirmation Test
Evaluation of the above tests was carried out by performing each procedure on each of
eight tailing samples and four waste rock samples from Canadian mines. This report
presents all of the data produced in the evaluations and provides discussion on each
method and its performance relative to the other tests of similar procedure and
objective.
From the results of the study it is concluded that confident prediction of acid mine
drainage is not likely to be achieved in a single test. Static tests are recommended for
use for initial screening of samples, followed by some form of kinetic weathering test to
confirm the initial prediction and to provide drainage quality and kinetic data. Several
static and kinetic tests were shown to provide credible prediction Of field AMD
behaviour. Choice of method can be made on the basis of the comparison of simplicity,
time required, equipment required, cost, ease of interpretation and correlation with the
field data. Results indicate that the mode of waste deposition in the field can also affect
the Choice of test used. some tests were shown to be unrealistic in their methodology.
In other cases, data obtained was believed to be unreliable or difficult to interpret.
Changes to established procedures have been suggested and recommended to
facilitate performance and interpretation of certain existing test methods and/or to
improve the accuracy of AMD prediction. in addition’, recommendations have been
made for further research, development, and evaluation of existing and new methods
to provide more reliable procedures and equipment for confident AMD prediction in the
future.
