2015-01-20_REVISION - P2009025 (6)

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"Although the diameter of the casing for a monitoring well depends on the purpose of the well, the casing size is generally selected to accommodate downhole equipment. Additional casing diameter selection criteria include: 1) drilling or well installation method used, 2) anticipated depth of the well and associated strength requirements 3) anticipated method of well development, 4) volume of water required to be purged prior to sampling, S) rate of recovery of the well after purging, and 6) anticipated aquifer testing. " "To minimize the volume of contaminated water that must be purged before sampling, Cal EPA recommends the use of either 2 -inch or 4 -inch diameter wells whenever practical (generally to depths less than 200 feet). The use of larger diameter wells may be necessary where dedicated purging or sampling equipment is used or where the well is screened in a deep formation. When considering whether to install larger diameter wells, the investigator should recognize that the quantity of contaminated groundwater that will require proper disposal and, for some hydrogeologic settings (i.e., zones of low hydraulic conductivity), the time required for well recovery will increase with well diameter. "... maximum annular space - S inches. Annular space widths larger than S inches may reduce the ability to develop a well, or may contribute to casing damage from heating during grout curing. "However, where precise geologic or hydrogeologic information is needed from deep boreholes (significantly greater than 200 feet), borehole deviation surveys are recommended. The depth of each monitoring well is determined by site - specific hydrogeologic conditions and monitoring objectives. For example, wells may be designed to monitor the water table, within a water - bearing zone or at the base of an aquifer. http: // www. dtsc. ca. gov/ SiteCleanup/ upload /SMP_Monitoring_Well_Design.pdf 8. Is there proper "site- specific hydrogeologic information " in order to proceed? BLR's Taylor Ranch Project Baseline Hydrologic Monitoring Plan contained 33 pages of hydrologic information. Although it was never performed, it was comprehensive. This monitoring plan is nothing more than a reiteration of the original NOI with a one -page map showing the location of monitoring wells with no hydrologic information whatsoever. Is this monitoring plan comprehensive enough given the method of mining BLR says it will use? 9. Will this monitoring plan be reviewed by a Third Party Expert per rule 1.4.3?