Construction Guidance for Class I ... .gov

When drilling has advanced to a confining rock stratum below the lowest underground source of drinking water (USDW) [30 TAC §331.62(a)(1)(A)], drilling temporarily ceases, the bit and drill pipe are removed from the hole, and open-hole well logging is performed according to rule requirements [30 TAC §331.62(a)(7)]. ................
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