A Digital Quality Control Audit of Staged Lugeon Tests Using Sparse Field Records

Routine staged Lugeon records often retain one pressure–flow representative per stage. We developed an auditable sequence that recalculates the nominal high-stage index, compares repeated-pressure pairs, screens grade margins and checks the evidence required for each interpretation. Sixteen single-packer intervals from three mudstone boreholes provided 80 stage representatives and 32 repeated-pressure pairs. All 16 project grades were reproduced; the nominal index ranged from 0.45 to 15.15 Lu (median 0.96). Four intervals crossed the 1-Lu boundary under ±10% index scaling. Across nine assumed head and line-loss combinations, zero to four grades changed. With assumed independent ±5% flow and pressure bounds, four grades were ambiguous; 11 of 32 pair-difference signs remained fixed under ±5% flow bounds. These conditional results identify boundary-adjacent records for source checks. An ordinal evidence inventory supports nominal arithmetic and a descriptive comparison and specifies corrected pressure, stable windows, seal-state records and calibration as prerequisites for causal diagnosis or control assessment.