Acid Rock Drainage _ARD_ by gjjur4356



                                                                             Issue No. sol-030e

     Acid Rock Drainage (ARD)
     Determining the Quality of Drainage Water

     ARD, what is it?                             Acid Potential (AP) and paste pH. A number
                                                  of procedures are available for both NP and

    N    atural water chemistry is influenced AP. Site conditions and local regulations
         by a variety of natural and man-made should be considered prior to requesting a
    processes. Acid rock drainage (ARD) given analysis procedure.
    results from atmospheric oxidation of
                                                  Neutralization Potential Procedures -
    sulphide bearing minerals (e.g. pyrites)
                                                  These chemical methods are used to establish
    to produce acidic species. Although this
                                                  a value for potential acid consumption. All
    phenomenon can occur naturally, ARD is
                                                  methods involve:
    commonly found in soil or rock that has
    been disturbed by human activity (e.g. • the reaction of a sample with a mineral
    logging, mining and construction activities).     acid of measured quantity
    The acid produced by ARD processes can •         the determination of the base equivalency
    alter water chemistry to the point where         of the acid consumed
    significant environmental impact can be
                                              •      the conversion of measured quantities
    observed. Thiobacillae bacteria are known
                                                     to a Neutralizing Potential in g/kg or
    to accelerate ARD generation processes.1
                                                     kg/tonne or tonne/1000 tonne calcium
                                                     carbonate (CaCO3)
     ARD Prediction Techniques

    The prediction of ARD production is made
    difficult because of the number of factors
    at work (e.g. rain and runoff, conditions for
    bacterial growth and chemical processes).
    Various techniques are commonly used to
    predict whether a material is prone to ARD
    Acid-Base Accounting (ABA) - ABA
    analyses are static tests that include
    Neutralization Potential (NP),

      Please turn over for:                         1)

     ARD Prediction Techniques con’t..., Capabilities, Quality Assurance, How to Contact Us
ARD Prediction Techniques con’t...                        Acid-Base Accounting Parameters:
Acid Potential Procedures - These procedures             •    Net Neutralization Potential (NNP)
involve the determination of theoretical acid
production. Both Total Sulphur and Sulphide              •    Maximum Potential Acidity (MPA)
Sulphur (obtained from the difference between
Total Sulphur and Sulphate Sulphur) may be used          •    Neutralization Potential & Fizz Rating
for this prediction tool.
Sulphur Content - The sulphur content of a               •    Ratio of Neutralization Potential: MPA (Calculation)
solid sample can be measured rapidly using
instrumental methods. This procedure can be used         •    Paste pH
as a screening method to quickly assess samples
and determine whether more intensive assessments         •    Total Sulfur
should be carried out.
                                                         •    Water - Leachable Sulfate

Capabilities                                             •    Sulfide (Calculated: Total S - Sulfate S)
Maxxam routinely performs the following ARD
prediction procedure:
•      Modified Acid Base Accounting Procedure for         Quality Assurance
       Neutralizing Potential (Lawrence)
                                                         Canmet ARD reference materials are analysed with
Other reference procedures can be provided upon
                                                         each batch of samples for Sulphur, NP, AP and Net
request. Please call for availability.
                                                         Neutralization Potential (NNP).

Additional capabilities include:
•      sulphate and sulphide analyses
•      microbiological assessments (e.g. Thiobacillae
•      crushing, grinding and pulverizing equipment
       (e.g. Braun chipmunk crusher; Bico pulverizer;
       large and small Wiley mills)
•      splitting, riffling and sieving equipment

For more information about ARD, please contact one of our Sales and Service Representatives by
calling (800) 440-4808.
British Columbia         Alberta              Ontario                 Quebec                 Atlantic Canada
    Burnaby              Calgary, Edmonton,   Mississauga, Guelph,    Montreal              Bedford & Sydney, NS
    Toll free:           Fort McMurray        Burlington              Toll free:            St. John’s, NL
    (800) 440-4808       Toll free:           Toll free:              (877) 462-9926        Toll free:
                         (800) 386-7247       (800) 563-6266                                (800) 565-7227


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