Difference between revisions of "Table 5-1"

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===Table 5-1: Methods for Geochemical Characterization===
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'''Return to: [[Chapter_5#5.3.2 Description of Phases|5.3.2 Description of Phases]]'''
 
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<table border="1" cellspacing="0" cellpadding="0" width="1100">
 
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  <tr>
 
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    <td width="137" bgcolor="#dddddd"><p align="center"><strong>Test Type</strong></p></td>
 
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    <td width="240" bgcolor="#dddddd"><p align="center"><strong>Test Methods and Description</strong></p></td>
 
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    <td width="240" bgcolor="#dddddd"><p align="center"><strong>Use in Geochemical  Characterization and Water Quality Prediction</strong></p></td>
 
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    <td width="241" bgcolor="#dddddd"><p align="center"><strong>Advantages</strong></p></td>
 
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    <td width="240" bgcolor="#dddddd"><p align="center"><strong>Limitations</strong></p></td>
 
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  </tr>
 
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    <td width="137" rowspan="3"><p align="center"><strong>Grain Size</strong></p></td>
 
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    <td width="240" valign="top"><p>Sieve</p></td>
 
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    <td width="240" rowspan="3" valign="top"><p>Predict reactivity on basis of available surface area</p></td>
 
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    <td width="241" valign="top"><p>Relatively rapid, less expensive</p></td>
 
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    <td width="240" valign="top"><p>Little information on fine fraction<br />No information on &quot;reactive&quot; fraction</p></td>
 
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  </tr>
 
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    <td width="240" valign="top"><p>Hydrometer</p></td>
 
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    <td width="241" valign="top"><p>Information on fine fraction</p></td>
 
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    <td width="240" valign="top"><p>More time consuming, more expensive<br />No information on &quot;reactive&quot; fraction</p></td>
 
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  </tr>
 
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  <tr>
 
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    <td width="240" valign="top"><p>BET method</p></td>
 
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    <td width="241" valign="top"><p>Sophisticated technique<br />Information on &quot;reactive&quot; fraction through measurement of total and specific surface area</p></td>
 
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    <td width="240" valign="top"><p>Time consuming and expensive<br />Requires specialized equipment and personnel</p></td>
 
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  </tr>
 
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  <tr>
 
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    <td width="137" rowspan="3"><p align="center"><strong>Chemical Composition</strong></p></td>
 
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    <td width="240" valign="top"><p>Digestion using various acids for analysis by multiple quantitative techniques (ICP-AES, ICP-MS, AAS, NAA) </p></td>
 
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    <td width="240" rowspan="3" valign="top"><p>Determines total potential load of constituents to environment.</p></td>
 
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    <td width="241" rowspan="3" valign="top"><p>Comparison against site-specific baseline values and reference geologic materials<br />Surrogate for and confirmation of ABA parameters (e.g., Ca, S)<br />Surrogate for and confirmation of mineralogical composition<br />Evaluation of sample set representativeness</p></td>
 
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    <td width="240" rowspan="3" valign="top"><p>Instrument-specific interferences<br />Volatilization<br />Elevated detection limits due to dilution </p></td>
 
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  </tr>
 
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  <tr>
 
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    <td width="240" valign="top"><p>Preparation of bead/powder sample for semi-quantitative analysis by XRF</p></td>
 
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  </tr>
 
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  <tr>
 
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    <td width="240" valign="top"><p>Portable equipment (XRF)</p></td>
 
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  </tr>
 
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  <tr>
 
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    <td width="137"><p align="center"><strong>Paste pH/Paste Conductivity</strong></p></td>
 
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    <td width="240" valign="top"><p>Mixture of solution and solid in desired ratio (typically 1:1 to 5:1) followed by pH/electrical conductivity measurement</p></td>
 
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    <td width="240" valign="top"><p>Determines potential short-term effect of surficial/soluble salts on water quality</p></td>
 
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    <td width="241" valign="top"><p>Quick, inexpensive, easy to perform in field and laboratory<br />Can be useful monitoring test for operational mine waste management</p></td>
 
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    <td width="240" valign="top"><p>Lack of ability to predict long-term conditions <br />Measures stored acidity </p></td>
 
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  </tr>
 
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  <tr>
 
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    <td width="137" rowspan="12"><p align="center"><strong>Acid Base Accounting (ABA)</strong></p></td>
 
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    <td width="240" valign="top"><p><strong><em>Sobek Method</em></strong><br />AP commonly from total sulphur<br />NP by boiling, HCl to pH 0.8-2.5</p></td>
 
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    <td width="240" valign="top"><p><u>All Methods:</u><br />Establish overall acid generating and acid neutralizing capability of a material through independent determination<br />Identification of the need for and samples that require kinetic testing </p></td>
 
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    <td width="241" valign="top"><p><u>All Methods:</u><br />Most techniques well established<br />Generally relatively fast and inexpensive<br />Provide operational screening criteria for mine waste classification and management </p></td>
 
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    <td width="240" valign="top"><p><u>All Methods:</u><br />Provide no information on relative rates of acid generation and neutralization<br />Assume NP and AG sulfur or minerals are completely available for reaction<br />Can over- or under-estimate AG or NP depending on method used  <br />NPR cannot be calculated in the absence of sulphur and sulphide<br />Acid addition dependent on a subjective fizz test which can affect accuracy</p></td>
 
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  </tr>
 
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  <tr>
 
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    <td width="240" valign="top"><p><strong><em>Modified Sobek (Lawrence Method)</em></strong><br />AP from sulphide sulphur<br />NP at ambient temperature for 24 hours near boiling, HCl to pH 2.0-2.5</p></td>
 
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    <td width="240" valign="top">&nbsp;</td>
 
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    <td width="241" valign="top"><p>Prevent over-estimation of NP or AP relative to Sobek method<br />Widely used</p></td>
 
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    <td width="240">&nbsp;</td>
 
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  </tr>
 
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  <tr>
 
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    <td width="240" valign="top"><p><strong><em>Lapakko</em></strong><br />NP at ambient temperature up to 1 week, H2SO4 to pH 6.0</p></td>
 
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    <td width="240">&nbsp;</td>
 
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    <td width="241">&nbsp;</td>
 
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    <td width="240">&nbsp;</td>
 
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  </tr>
 
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    <td width="240" valign="top"><p><strong><em>BC Research Inc. (BCRI) Initial</em></strong><br />NP at ambient temperature for 16-24 hours, H2SO4 to pH 3.5</p></td>
 
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    <td width="240">&nbsp;</td>
 
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    <td width="241">&nbsp;</td>
 
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    <td width="240">&nbsp;</td>
 
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  </tr>
 
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  <tr>
 
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    <td width="240" valign="top"><p><strong><em>Sobek Siderite Correction</em></strong><br />as Sobek, but with H2O2</p></td>
 
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    <td width="240" valign="top"><p>Accounts for complete oxidation of soluble metals during titration</p></td>
 
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    <td width="241"><p>ASTM draft method uses sulphuric acid  Requires no fizz test<br />Uses pH to determine acid addition requirements<br />Negative values indicate stored acid</p></td>
 
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    <td width="240">&nbsp;</td>
 
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  </tr>
 
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  <tr>
 
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    <td width="240" valign="top"><p><strong><em>Net Carbonate Value (NCV),%CO2</em></strong><br />NCV = ANP + AGP, where<br />AGP = -1.37[(total sulphur) - (residual sulphur after pyrolysis)]<br />ANP = 3.67[(total carbon) - (carb on after HCl digestion)] (=see TIC) </p></td>
 
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    <td width="240" valign="top"><p>Developed by Newmont <br />Negative ANP and positive AGP must be corrected to zero  <br />Negative NCV indicates acid generation potential<br />Confirm NCV classification using BC Research Confirmation on zone composites</p></td>
 
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    <td width="241" valign="top"><p>Standardized as ASTM E-1915  <br />Waste rock composites characterized with metallurgical suite for ores  <br />Several options for sulphide confirmation depending on mineralogy <br />Classification system limits uncertainty</p></td>
 
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    <td width="240" valign="top"><p>Requires carbon-sulphur sophisticated  combustion-infrared instrumentation similar to Sobek <br />Results require conversion for comparison against data from other ABA tests in order to differentiate methods<br />Metal carbonates overestimate ANP<br />Does not account for silicate buffering or stored acidity</p></td>
 
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  </tr>
 
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  <tr>
 
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    <td width="240" valign="top"><p><strong><em>Acid Buffering Characteristic Cu</em></strong><strong><em>rve</em></strong> <strong><em>(ABCC)</em></strong><br />Titration of sample with acid while continuously monitoring pH </p></td>
 
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    <td width="240" valign="top"><p>Provides an indication of the portion of the NP that is readily available for neutralization<br />Used principally in Australia<br />Similar in nature to the BCRI Initial test</p></td>
 
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    <td width="241" valign="top"><p>Can be used to identify minerals responsible for neutralization by comparing against ABCCs for reference minerals<br />Well suited for measuring actual NP vs. total NP<br />Represents a less conservative method of measuring NP</p></td>
 
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    <td width="240" valign="top"><p>Only feasible to do on selected samples due to long test time <br />Limited basis for comparison against results from more &quot;traditional&quot; ABA tests due to limited use to date</p></td>
 
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  </tr>
 
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  <tr>
 
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    <td width="240" valign="top"><p><strong><em>Total Inorganic Carbon (TIC)</em></strong><br />TIC = (total carbon) - (carbon after HCl digestion)</p></td>
 
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    <td width="240">&nbsp;</td>
 
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    <td width="241" valign="top"><p>Measures NP associated with carbonates only</p></td>
 
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    <td width="240" valign="top"><p>Only provides carbonate fraction of NP<br />Can only be used in concert with total NP results<br />Will include carbonates that do not contribute NP (e.g., siderite)<br />Not suitable for materials with low NP</p></td>
 
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  </tr>
 
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  <tr>
 
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    <td width="240"><p><strong><em>Sulphur Analysis</em></strong><br />(total S, pyritic S, sulphide S, organic S, sulphate S, residual S)<br />Analysis requires selective digestion of ground sample and measurement of sulphur by infrared or titration after combustion<br />Removal of non-sulphide and/or targeted sulphide minerals to determine sulphur species</p></td>
 
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    <td width="240" valign="top"><p>Potential of samples to generate acid<br />Used as part of ABA testing</p></td>
 
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    <td width="241" valign="top"><p>Distinguishes between sulphur forms and allows identification of &quot;reactive&quot; sulphur species</p></td>
 
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    <td width="240" valign="top"><p>Does not confirm the identity of the sulphur-bearing mineral(s)<br />Can overestimate or underestimate reactive sulphur content</p></td>
 
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  </tr>
 
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  <tr>
 
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    <td width="240" valign="top"><p><strong><em>Chromium Reducible Sulphur</em></strong><br />Targets acid-volatile sulphur, elemental sulphur and pyrite sulphur through HCl digestion </p></td>
 
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    <td width="240" rowspan="3" valign="top"><p>Used principally in acid sulphate soils investigations. CRS is also useful for sulphide analysis in coal and coal reject materials</p></td>
 
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    <td width="241" valign="top"><p>Considered a very reliable method for measuring low-level sulphur concentrations<br />Only measures sulphide minerals</p></td>
 
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    <td width="240" rowspan="3" valign="top"><p>Limited basis for direct comparison against results from more &quot;traditional&quot; ABA tests</p></td>
 
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  </tr>
 
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  <tr>
 
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    <td width="240" valign="top"><p><strong><em>Total Actual Acidity (TAA)</em></strong><br />Titration of KCl extract to pH 5.5 with NaOH</p></td>
 
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    <td width="241" valign="top"><p>Can define actual acidity in low-pH samples that have oxidized </p></td>
 
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  </tr>
 
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  <tr>
 
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    <td width="240"><p><strong><em>Total Potential Acidity (TPA)</em></strong><br />Heating of KCl extract with H2O2 and titration to pH 5.5 with NaOH</p></td>
 
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    <td width="241">&nbsp;</td>
 
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  </tr>
 
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  <tr>
 
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    <td width="137" rowspan="4"><p align="center"><strong>Net Acid Generating (NAG)</strong></p></td>
 
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    <td width="240" valign="top"><p><strong><em>Single addition NAG</em></strong><br />Reaction with H2O2, measurement of the NAG pH and titration to pH 4.5 and pH 7.0 with NaOH</p></td>
 
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    <td width="240" rowspan="4" valign="top"><p><u>All Methods:</u><br />Establishes overall acid generating capability of a material through simultaneous reaction of acid generating and acid neutralizing components<br />Identification of the need for and samples that require kinetic testing  Used in conjunction with ABA or stand alone field test when calibrated<br />
 
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      </p></td>
 
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    <td width="241" valign="top"><p><u>All Methods:</u><br />Evaluates net acid-base balance<br />Generally relatively fast and inexpensive<br />Provides operational screening criteria for mine waste classification and management <br />Greatly reduces false positive and false negative ABA results <br />Confirmation results for unreactive materials<br />In combination with ABA improves prediction reliability and range of uncertainty </p></td>
 
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    <td width="240" rowspan="4" valign="top"><p><u>All Methods:</u><br />Does not distinguish between AP and NP<br />Potential interferences in presence of organic carbon and copper<br />May underestimate ARD potential in high-sulphide material due to incomplete oxidation (Sequential NAG addresses this limitation)<br />Quality of H2O2 may vary: some H2O2 brands required pre-treatment for NAG test use  </p></td>
 
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  </tr>
 
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  <tr>
 
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    <td width="240" valign="top"><p><strong><em>Sequential NAG</em></strong><br />Multi-stage repeat of single-addition NAG tests until NAG pH is greater than 4.5</p></td>
 
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    <td width="241" valign="top"><p>Overcomes incomplete oxidation in high-sulphur samples<br />Can provide qualitative estimate of approximate lag time to acid generation</p></td>
 
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  </tr>
 
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  <tr>
 
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    <td width="240" valign="top"><p><strong><em>Extended Boil and Calculated NAG</em></strong><br />As single addition NAG, but accounts for potential effect from organic matter<br />Extended boiling and assay of the NAG solution for S, Ca, Mg, Cl, Na and K </p></td>
 
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    <td width="241" valign="top"><p>Accounts for potential effect from organic matter</p></td>
 
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  </tr>
 
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  <tr>
 
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    <td width="240" valign="top"><p><strong><em>Kinetic NAG</em></strong><br />As single addition NAG but with monitoring of temperature and pH during reaction with H2O2</p></td>
 
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    <td width="241" valign="top"><p>Provides qualitative estimate of reaction kinetics and lag time (i.e., weeks, months, years)</p></td>
 
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  </tr>
 
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  <tr>
 
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    <td width="137" rowspan="6"><p align="center"><strong>Mineralogical Composition</strong></p></td>
 
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    <td width="240" valign="top"><p><strong><em>Visual/Optical Microscopy</em></strong><br />Hand lens, binocular microscope</p></td>
 
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    <td width="240" rowspan="6" valign="top"><p><u>All Methods:</u><br />Identify primary and secondary minerals that could affect acid generation potential and contact water quality<br />With increasing sophistication of techniques, also information on texture, mineral composition and morphology to evaluate mineral reactivity and availability for weathering reactions that can affect acid generation and leaching potential </p></td>
 
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    <td width="241" valign="top"><p><u>All Methods:</u><br />Provide information on acid generating potential and NP, availability of minerals for weathering<br />Corroborate lithologic information<br />Essential for understanding of geochemical controls on contact water quality and as inputs to geochemical model simulations </p></td>
 
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    <td width="240" valign="top"><p>Qualitative</p></td>
 
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  </tr>
 
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  <tr>
 
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    <td width="240" valign="top"><p><strong><em>X-ray diffraction (XRD)</em></strong><br />Qualitative or semi-quantitative (Rietveld) analysis</p></td>
 
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    <td width="241" valign="top">&nbsp;</td>
 
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    <td width="240" valign="top"><p>Semi-quantitative at best</p>
 
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      <br clear="all" />
 
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      <p>High detection limit ~1%</p>
 
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      <br clear="all" />
 
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      <p>Capable of identifying crystalline minerals only</p></td>
 
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  </tr>
 
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  <tr>
 
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    <td width="240" valign="top"><p><strong><em>Petrographic analysis</em></strong><br />Reflection or transmission petrographic microscope</p></td>
 
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    <td width="241" valign="top">&nbsp;</td>
 
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    <td width="240" rowspan="3" valign="top"><p>Requires sophisticated instrumentation and specialized personnel for interpretation</p></td>
 
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  </tr>
 
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  <tr>
 
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    <td width="240" valign="top"><p><strong><em>SEM/EDS</em></strong><br />Electron beam scan for mineral identification</p></td>
 
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    <td width="241" valign="top"><p>Surpasses combustion-infrared methods in quantifying trace sulfide mineral concentrations </p></td>
 
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  </tr>
 
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  <tr>
 
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    <td width="240" valign="top"><p><strong><em>Electron microprobe</em></strong><br />Like SEM but optimized for chemical analysis </p></td>
 
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    <td width="241" valign="top">&nbsp;</td>
 
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  </tr>
 
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  <tr>
 
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    <td width="240" valign="top"><p><strong><em>Portable equipment (PIMA)</em></strong><br />Infrared analyzer</p></td>
 
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    <td width="241" valign="top"><p>Portable<br />Particularly suited for hydrated minerals</p></td>
 
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    <td width="240" valign="top"><p>Not capable of identifying all minerals</p></td>
 
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  </tr>
 
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  <tr>
 
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    <td width="137" rowspan="17"><p align="center"><strong>Short-Term Leach Tests</strong></p></td>
 
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    <td width="240" valign="top"><p><strong><em>SPLP (Synthetic Precipitation Leaching Procedure)</em></strong><br />US EPA Method 1312<br />20:1 solution to solid<br />Deionized water or dilute sulphuric/nitric acid to pH 4.2 or 5.0<br />&lt; 9.5 mm<br />18 ± 2 hours<br />Variant: <strong><em>Standard Test Method for Shake Extraction of Mining Waste by the Synthetic Precipitation Leaching Procedure</em></strong><br />ASTM D 6234</p></td>
 
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    <td width="240" valign="top"><p><u>All Methods:</u><br />Measures readily soluble constituents of mine and process wastes</p></td>
 
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    <td width="241" valign="top"><p><u>All Methods:</u><br />Provides indication of short-term leaching of soluble constituents.<br />Identifies readily dissolvable constituents<u></u></p></td>
 
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    <td width="240" valign="top"><p><u>All Methods:</u><br />Provides no information on transient processes and long-term conditions. <br />Only simulates short-term interaction<br />High liquid to solid ratio may underestimate leachability<br />Grain size reduction may increase reactivity</p></td>
 
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  </tr>
 
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  <tr>
 
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    <td width="240" valign="top"><p><strong><em>TCLP (Toxicity Characteristic Le</em></strong><strong><em>aching Procedure)</em></strong><br />US EPA Method 1311<br />20:1 solution to solid ratio<br />acetic acid/acetate buffer<br />&lt; 9.5 mm<br />18 ± 2 hours </p></td>
 
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    <td width="240" valign="top"><p>Used to determine if waste is hazardous under RCRA<br />Intended to simulate municipal landfill containing organic wastes</p></td>
 
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    <td width="241" valign="top"><p>Applicable standards available</p></td>
 
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    <td width="240" valign="top"><p>Use of acetic acid/acetate buffers not appropriate for mining applications, Short list of metals evaluated </p></td>
 
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  </tr>
 
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  <tr>
 
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    <td width="240" valign="top"><p><strong><em>Meteoric Water Mobility Procedure (MWMP)</em></strong><br />1:1 solution to solid ratio<br />reagent-grade water<br />&lt; 2 inch<br />&lt; 48 hours</p></td>
 
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    <td width="240" valign="top"><p>Same as for SPLP<br />Primarily used in Nevada</p></td>
 
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    <td width="241" valign="top"><p>Quasi-dynamic test<br />More realistic than SPLP due to higher solid to solution ratio, longer duration and coarser material<br />Applicable standards available</p></td>
 
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    <td width="240" valign="top"><p>Weaker lixiviant than acidified SPLP</p></td>
 
−
  </tr>
 
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  <tr>
 
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    <td width="240" valign="top"><p><strong><em>California Waste Extraction Test (WET)</em></strong><br />10:1 solution to solid ratio<br />dilute sodium citrate solution<br />&lt; 2 mm<br />48 hours </p></td>
 
−
    <td width="240" valign="top"><p>Intended to simulate municipal landfill containing organic wastes <br />Primarily used in California</p></td>
 
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    <td width="241" valign="top"><p>Lower liquid to solid ratio and longer test duration than SPLP and TCLP<br />Applicable standards available</p></td>
 
−
    <td width="240" valign="top"><p>Use of sodium citrate not appropriate for mining applications</p></td>
 
−
  </tr>
 
−
  <tr>
 
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    <td width="240" valign="top"><p><strong><em>Modified Test for Shake Extraction of Solid Waste with Water</em></strong><br />4:1 solution to solid ratio<br />reagent-grade water adjusted to pH 5.5 with carbonic acid<br />18 hours </p></td>
 
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    <td width="240" valign="top"><p>Same as for SPLP</p></td>
 
−
    <td width="241" valign="top"><p>Lower liquid to solid ratio than SPLP</p></td>
 
−
    <td width="240" valign="top">&nbsp;</td>
 
−
  </tr>
 
−
  <tr>
 
−
    <td width="240" valign="top"><p><strong><em>British Columbia Special Waste Extraction Procedure (BC SWEP)</em></strong><br />20:1 solution to solid ratio<br />acetic acid<br />&lt; 9.5 mm<br />24 hours<br /><strong><em>Modification for mining </em></strong><strong><em>wastes</em></strong> <br />3:1 solution to solid ratio<br />dilute hydrochloric acid </p></td>
 
−
    <td width="240" valign="top"><p>Similar to TCLP for normal procedure<br />Similar to SPLP and ASTM for modified procedure</p></td>
 
−
    <td width="241" valign="top"><p>Modified: lower solution to solid ratio than SPLP and ASTM</p></td>
 
−
    <td width="240" valign="top"><p>Intended to simulate municipal landfill containing organic wastes <br />Same as for SPLP</p></td>
 
−
  </tr>
 
−
  <tr>
 
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    <td width="240" valign="top"><p><strong><em>NAG Test with Leachate Analysis</em></strong><br />100:1 solution to solid ratio<br />15% H2O2 solution<br />&lt; 75 um<br />Until boiling or effervescing ceases</p></td>
 
−
    <td width="240" valign="top"><p>Can be used to determine total potential loading or release of metals after complete oxidation of reactive sulphides</p></td>
 
−
    <td width="241" valign="top"><p>&quot;Short-cut&quot; to conditions representative of complete sulphide oxidation</p></td>
 
−
    <td width="240" valign="top"><p>Leachate contains all reaction products from sulphide oxidation<br />High solution to solid ratio<br />Significant grain size reduction</p></td>
 
−
  </tr>
 
−
  <tr>
 
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    <td width="240" valign="top"><p><strong><em>Characterization of Waste - Leaching - Compliance Test for Leaching of Granular Materials and Sludge</em></strong><br />EN 12457 1<br />One stage test<br />2:1 solution to solid ratio<br />&lt; 4 mm<br />EN 12457-2<br />One stage test<br />10:1 solution to solid ratio<br />&lt; 4 mm<br />EN 12457-3<br />Two stage test<br />2:1 and 8:1 solution to solid ratios<br />&lt; 4 mm<br />EN 12457-4<br />One stage test<br />10:1 solution to solid ratio<br />&lt; 10 mm<br />All Methods:<br />distilled/demineralized/deionized water<br />24 hours</p></td>
 
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    <td width="240" valign="top"><p><u>All European Union (EU) Methods:</u><br />Basic characterization: obtain information on leaching behavior and characteristics<br />Compliance: determine whether waste complies with specific reference values </p></td>
 
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    <td width="241" valign="top"><p><u>All European Union (EU) Methods:</u><br />Test protocol is adjusted based on information needs and site-specific conditions<br />Applicable standards available (expressed as loadings) </p></td>
 
−
    <td width="240" valign="top"><p>Same as for SPLP</p></td>
 
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  </tr>
 
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  <tr>
 
−
    <td width="240" valign="top"><p><strong><em>Characterization of Waste - Leaching </em></strong><strong><em>Behavior</em></strong><strong><em> Tests - Up-flow Percolation Test</em></strong><br />CEN/TS 14405<br />10:1 solution to solid ratio<br />&lt; 10 mm<br />demineralized water<br />duration as needed </p></td>
 
−
    <td width="240" valign="top"><p>Used to determine leachability of a waste under hydraulically dynamic conditions (EU)</p></td>
 
−
    <td width="241" valign="top"><p>Test can be used to establish the distinction between various release mechanisms (e.g., first flush vs. steady state leaching)</p></td>
 
−
    <td width="240" valign="top"><p>Same as for MWMP<br />Test developed for landfills</p></td>
 
−
  </tr>
 
−
  <tr>
 
−
    <td width="240" valign="top"><p><strong><em>Characterization of Waste - Leaching </em></strong><strong><em>Behavior</em></strong><strong><em> Tests - Influence of pH on Leaching with Initial Acid/Base</em></strong> Addition<br />CEN/TS 14429<br />10:1 solution to solid ratio<br />at least 8 individual solutions of different pH using nitric acid or sodium hydroxide covering the range pH 4-12<br />95% &lt; 1 mm<br />48 hours</p></td>
 
−
    <td width="240" valign="top"><p>Used to determine influence of pH on waste leachability and buffering capacity (EU)</p></td>
 
−
    <td width="241" valign="top"><p>Leachate analyzed for inorganic constituents (as opposed to prCEN/TS 15364)<br />pH is allowed to fluctuate after initial addition of acid or base<br />Allows evaluation of buffering capacity</p></td>
 
−
    <td width="240" valign="top"><p>Same as for SPLP<br />Test developed for landfills</p></td>
 
−
  </tr>
 
−
  <tr>
 
−
    <td width="240" valign="top"><p><strong><em>Characterization of Waste - Leaching </em></strong><strong><em>Behavior</em></strong><strong><em> Tests - Influence of pH on Leaching with Continuous pH-Control</em></strong><br />EN 14997<br />10:1 solution to solid ratio<br />at least 8 individual solutions of different pH using nitric acid or sodium hydroxide covering the range pH 4-12<br />95% &lt; 1 mm<br />48 hours</p></td>
 
−
    <td width="240" valign="top"><p>Used to determine influence of pH on waste leachability (EU)</p></td>
 
−
    <td width="241" valign="top"><p>Leachate analyzed for inorganic constituents (as opposed to prCEN/TS 15364)<br />pH is maintained at constant value after initial addition of acid or base<br />Allows evaluation of leachability under constant pH</p></td>
 
−
    <td width="240" valign="top"><p>Same as for SPLP<br clear="all" />
 
−
        Test developed for landfills</p></td>
 
−
  </tr>
 
−
  <tr>
 
−
    <td width="240" valign="top"><p><strong><em>Characterization of Waste - Leaching </em></strong><strong><em>Behavior</em></strong><strong><em> Tests - Acid and Base </em></strong><strong><em>Neutralization</em></strong><strong><em> Capacity Test</em></strong><br />CEN/TS 15364<br />10:1 solution to solid ratio<br />at least 8 individual solutions of different pH using nitric acid or sodium hydroxide covering the range pH 4-12<br />95% &lt; 1 mm<br />48 hours </p></td>
 
−
    <td width="240" valign="top"><p>Used to determine final pH of a waste as well as assess consequences of external influences (carbonation, oxidation) on the final pH (EU)</p></td>
 
−
    <td width="241" valign="top">&nbsp;</td>
 
−
    <td width="240" valign="top"><p>Same as for SPLP<br />Test developed for landfills<br />Leachate only analyzed for pH</p></td>
 
−
  </tr>
 
−
  <tr>
 
−
    <td width="240" valign="top"><p><strong><em>Lixiviação de Resíduos</em></strong><br />NBR 10005<br />16:1 solution to solid ratio<br />acetic acid<br />&lt; 9.5 mm<br />24 hours</p></td>
 
−
    <td width="240" valign="top"><p>Used to determine if mine waste is hazardous under solid waste regulations (Brazil)<br />Intended to simulate municipal landfill containing organic wastes</p></td>
 
−
    <td width="241" valign="top"><p>Applicable standards available</p></td>
 
−
    <td width="240" valign="top"><p>Use of acetic acid not appropriate for mining applications</p></td>
 
−
  </tr>
 
−
  <tr>
 
−
    <td width="240" valign="top"><p><strong><em>Solubilização de Resíduos</em></strong><br />NBR 10006<br />4:1 solution to solid ratio<br />deionized water<br />grain size not specified<br />7 d<strong>ays</strong></p></td>
 
−
    <td width="240" valign="top"><p>Used to evaluate potential for impacts to groundwater by comparison against groundwater quality standards (Brazil)</p></td>
 
−
    <td width="241" valign="top"><p>Applicable standards available<br />Lower solution to solid ratio and longer duration than SPLP</p></td>
 
−
    <td width="240" valign="top"><p>Same as for SPLP</p></td>
 
−
  </tr>
 
−
  <tr>
 
−
    <td width="240" valign="top"><p><strong><em>Test Method Standard for Leaching Toxicity of Solid Wastes - Roll Over Leaching Procedure</em></strong><br />GB5086.1-1997<br />10:1 solution to solid ratio<br />deionized/distilled water<br />&lt; 5 mm<br />18 hours </p></td>
 
−
    <td width="240" valign="top"><p>Used to determine if mine waste is hazardous under solid waste regulations by comparison against Integrated Wastewater Discharge Standards (China)</p></td>
 
−
    <td width="241" valign="top"><p>Applicable standards available</p></td>
 
−
    <td width="240" valign="top"><p>Same as for SPLP</p></td>
 
−
  </tr>
 
−
  <tr>
 
−
    <td width="240" valign="top"><p><strong><em>Test Method Standard for Leaching Toxicity of Solid Wastes - Horizontal Vibration Extraction Proc</em></strong><strong><em>edure</em></strong><br />GB5086.2-1997<br />10:1 solution to solid ratio<br />deionized/distilled water<br />&lt; 3 mm<br />24 hours </p></td>
 
−
    <td width="240" valign="top"><p>Used to determine if mine waste is hazardous under solid waste regulations by comparison against Integrated Wastewater Discharge Standards (China)</p></td>
 
−
    <td width="241" valign="top"><p>Applicable standards available</p></td>
 
−
    <td width="240" valign="top"><p>Same as for SPLP</p></td>
 
−
  </tr>
 
−
  <tr>
 
−
    <td width="240" valign="top"><p><strong><em>Sequential Extraction<br /></em></strong>Variety of methods using different extractants to evaluate leachability from targeted fractions of mine waste<br />Methods may vary depending on analyte of interest and target fraction of interest<strong></strong></p></td>
 
−
    <td width="240" valign="top"><p>To evaluate associations between constituents of interests and different fractions of the solid<br />Allows for determination of the labile portion of the solid phase</p></td>
 
−
    <td width="241" valign="top"><p>Understanding associations of constituents with different fractions of the solid assists in understanding geochemical conditions under which they may be released to the environment</p></td>
 
−
    <td width="240" valign="top"><p>Involved procedure<br />Many reagents<br />Most reagents not uniquely selective to targeted fraction<br />Use of some reagents precludes analysis of certain constituents<br />No applicable standards</p></td>
 
−
  </tr>
 
−
  <tr>
 
−
    <td width="137" rowspan="2"><p align="center"><strong>Long-Term Leach Tests</strong></p></td>
 
−
    <td width="240" valign="top"><p><strong><em>Humidity Cell Test (HCT)</em></strong><br />ASTM D5744-96<br />0.5:1 or 1:1 solution to solid ratio<br />deionized water<br />different dimensions for &lt; 6.3 mm and &lt;150 μm<br />weekly cycle of 3-day alternating dry air and wet air followed by leach<br />generally 20-week minimum but can run longer<br />weekly analysis of diagnostic ARD parameters (e.g., pH, SC, Fe, SO4, Eh, Ca, Mg, alkalinity)<br />generally less-frequent analysis for comprehensive metals and major ions </p></td>
 
−
    <td width="240" valign="top"><p>To determine long-term weathering rates (sulphide oxidation, dissolution of neutralizing minerals, trace metal release) under oxygenated conditions<br />To evaluate lag time to acid generation<br />To provide reaction rates for geochemical modeling</p></td>
 
−
    <td width="241" valign="top"><p>Standardized test<br />Provides kinetic and steady-state leaching information and is recommended test for determination of weathering rates of primary minerals</p></td>
 
−
    <td width="240" valign="top"><p>Not suitable for evaluation of saturated materials<br />Grain size reduction may increase reactivity<br />Potential for channel flow<br />High leaching rate can affect reaction kinetics due to higher pH and undersaturation with secondary minerals </p></td>
 
−
  </tr>
 
−
  <tr>
 
−
    <td width="240" valign="top"><p><strong><em>Column Test</em></strong><br />variable solution to solid ratio<br />generally deionized water, groundwater  or natural precipitation<br />generally &lt; 25 mm<br />variable dimension, but generally larger than HCT<br />leaching cycles can vary and include maintaining water over sample, alternate flooding and draining, and recirculating leachate </p></td>
 
−
    <td width="240" valign="top"><p>As above, but can simulate leaching in variably saturated or oxygen-deficient conditions<br />To simulate environmental performance of amended mine wastes and/or cover designs</p></td>
 
−
    <td width="241" valign="top"><p>Frequently closer to field conditions than HCT<br />Can simulate different degrees of saturation<br />Can simulate remedial alternatives<br />Simulates combined weathering of primary and secondary minerals</p></td>
 
−
    <td width="240" valign="top"><p>Not standardized<br />Potential for channeling through preferential flowpaths<br />Grain size reduction may increase reactivity<br />Without entire load of weathering products from primary minerals, reaction rates for primary minerals and extent of secondary precipitation cannot be measured</p></td>
 
−
  </tr>
 
−
  <tr>
 
−
    <td width="137" rowspan="3"><p align="center"><strong>Field Tests</strong></p></td>
 
−
    <td width="240" valign="top"><p><strong><em>Wall Washing</em></strong><br />1L rinse of 1 × 1 m surface area<br />distilled water</p></td>
 
−
    <td width="240" rowspan="3" valign="top"><p><u>All Methods:</u><br />To estimate short and  long-term potential of mine materials to generate acid and leach metals using on-site materials </p></td>
 
−
    <td width="241" valign="top"><p>Rapid<br />Measures leachate quality from in situ material<br />Can be repeated to obtain temporal component</p></td>
 
−
    <td width="240" valign="top"><p>May be difficult to establish accurate mass balance due to loss of solution</p></td>
 
−
  </tr>
 
−
  <tr>
 
−
    <td width="240" valign="top"><p><strong><em>US Geological Survey Field Leach Test (FLT)</em></strong><br />20:1 solution to solid ratio<br />deionized water<br />&lt; 2 mm<br />5 minutes<br /><u>http://pubs.usgs.gov/tm/2007/05D03/</u></p></td>
 
−
    <td width="241" valign="top"><p>Can be performed in the field<br />Rapid and inexpensive method to characterize chemical reactivity and water-soluble fraction<br />Field screening method that can be used as surrogate for SPLP due to similarity in approach and results</p></td>
 
−
    <td width="240" valign="top"><p>Same as for SPLP</p></td>
 
−
  </tr>
 
−
  <tr>
 
−
    <td width="240" valign="top"><p><strong><em>Field Cells/Test Pads/Mine Facilities</em></strong><br />Monitoring of increasingly larger volumes of mine wastes<br />Ambient precipitation or irrigation<br />Degree of grain size reduction required decreases with increasing size of test<br />Test duration months to years </p></td>
 
−
    <td width="241" valign="top"><p>Test are conducted under actual field conditions<br />Can collect samples after transient events<br />Larger sample size results in enhanced test charge representativeness<br />With increasing test size, effects from grain size reduction, sample heterogeneity and preferential pathways reduced<br />With increasing test size, empirical results increasingly directly applicable to mine facility</p></td>
 
−
    <td width="240" valign="top"><p>Comprehensive characterization of test sample may not be feasible<br />Complete understanding of water balance may not be feasible<br />Complexity of tested system may limit interpretive and predictive value of observations</p></td>
 
−
  </tr>
 
−
</table>
 
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