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B2i 23194 I3: 21 S 702 356 8917 T<Glel lantl Lab BS • tti1cC1_I;LLAND I,A$URATURIES, INC. ___ _ ~~ ~ ~ ~ lulh theF bttcct, 5p;n l.w, N.:vaJa tlY111 -- iP7. / 15h~1100 r,~x ,n: i lse aor METALS MOBILITY TEST PROTOCOLS EXECUTING SUMMARY There arc several test protocols available to evaluate mine waste and process waste with respect to nlohilizatiun of metals by meteoric water. Some states, like Nevada, !rave developed their own lrsting protocol (NDL;P-MWM'T), while other states have adopted one ur more of the IJ.S. F.PA's toxic constitttcnt mobility tests. EPA tests include: CP-Toxicity (Method 1310). Toxicity Characteristic leaching Procedure (-TCLP-Metbod 13] ]), and Synthetic Precipitation Leaching Procedure (SPI,P-Method 1312). An ASTM procedure (Method D 39f;7-g5) designated Sltake Extraction of Solid Waste with Water is also available. That procedure was originally designed to determine buffering capacity of soils for agricultural purposes. The testing protocol seems to indicate that all three IiPA methods were generally patterned al'ler the ASTM method. Nunc of the four methods mentioned above adequtnely simulate metals mobility l>cltelltial resulting from a mercuric event principally because the solids are agitated by rolling at a 20:1 liquid to solid ratio. The rolling period is sufficiently long to establish equilibrium conditions in the dynamic system. L'yuilihrium cunditiuns, depending on pH, • can cause metals like arsenic u, precipitate or chemically react with the solids, and can cause other metals w mobilize more severely than for a percolation (simulated meteoric event) System like the Nevada Meteoric Water Mobility'I'esl (MWMT). In addition, agitation which creates multiple contacts oC solution and solids can cause volatilization and or oxidation of WAD cyanide compounds from processed wastes. Consequently, 1 feel the[ a more static system Jike the NDEP a,lumn percolation MWM'I procedure provides a more reasonable sintulatiun of a meteoric event, as well as providing a more accurate measure of potential for metals mnbilily from hard rock mining waste solids. We as an industry need as accurate data as possible so that we can identify all constituents which may irnpatt project area water quality if nut mitigated or mntmlled. 1:PA method 131() (FiP-'Toxicity) will be described in detail. Modifications to that method (1311, 1312, ASTM) are discussed separately. retailed procedures for all four methods are nut required beultlse protocols arr. essentially the same. The NDEP- MWMT column percolation procedure will also be discussed in detail. Comparative summary sheets fur the five test methods are attached fur your reference. Please keep in mind that proper, common sense, sampling procedures and prescrvatirnt techniques must be employee! before initiating any of the metals ntubility test procedures.