REV13408 - Laserfiche WebLink

Home Browse Search

ACID BASE ACCOUNTING FOR VLF SAMPLES: McClellantl Laboramries ABA SWO AG. ANP. NNP Imes CaCO,/1000 mwl Sample Pule pH S, 5 SO, AGP ANP NNP Rmio Cresson Phue 1 ~ ws !9 mesh ].]] ) 6 10 T d IJ Crcswn Phsse 11 - minus IA mesh 9.SB 5 ] 13 ].l :.) 4. In our discussions, it was explained that the Cresson valley leach facility samples had not been treated with hydrogen peroxide (HZOZ) prior to testing. That is because the samples had not been leached with the sodium cyanide solution. Therefore, the question arose as to whether oxidation products were accounted for. A hydrogen peroxide treatment of spent ore is conducted to oxidize the less-stable carbon nitrogen compounds to carbon and nitrogen oxides. It is quite possible that, during this application of Hz02, metallic compounds that are present in the solution also will be oxidized. The concentrations measured for water-quality evaluations will not change as a result of the HZOZ application. Whether or not these metallic compounds are oxidized, the metal will be detected. The oxidation process will not remove metals from the rock and will not, therefore, decrease or increase the metal concentrations. The humidity-cell generated data is an indicator of the quality of the water after cyanide removal. Review of the water quality data collected at a location downstream of the Carlton Mill (AG-1.5), in particular prior to relocation of the Carlton Mill Tailing, demonstrates that concentrations of regulated parameters, including trace metals, are low. Financial Warranty Releases: As stated in CC&V's letter dated November 11, 1998, it is understood that until the quality of the water contained in the spent ore of the valley leach facility is suitable for release, adequate financial warranty for incremental reapplication of chemical amendments such as hydrogen peroxide will be maintained by CC&V. The applicable regulations provide for partial releases of the financial warranty. For example, financial warranties for reclamation of overburden storage areas will be judged for release separate from reclamation of the valley leach facility. Testing -Environmental: A question arose about the adequacy of the proposed testing of the soil liner fill ("SLF"). When CC&V responded to this question in its letter of November I1, 1998, CC&V assumed that the OMLR was not aware of the testing frequency of one permeability test every 5,000 yd' in accord with ASTM D5084/2434 and, therefore, we clarified that frequency. This is a high testing frequency. Further, the source of SLF is scheduled to be that same general deposit area used for 1996 SLF and density tests are routinely performed. Because CC&V has simplified the grain size distribution specification, the OMLR wishes to increase the permeability testing if the standard frequency testing shows either non-compliance with the specified permeability limit or approaches that limit. If the permeability of the SLF is higher than 9.Ox 10-' cm/sec, CC&V will conduct a extra permeability test on a sample collected within a 10-foot radius of the first sample. The extra "10-foot radius" permeability test must meet the specifications of <_ 1x10.6 cm/sec. If a test on any 5,000 yd3 test interval fails (i.e., ti