The Carlton Mill administrative offices of Cripple Creek/Victor Gold Mining Company (CC/V) were served by a septic tank and leach field, both of which were located below a proposed heap-leach pad. Discharge from the wastewater system was expected to cause water table mounding below the leaching pad, which would confuse analysis of pad leakage by becoming tributary to the underdrain system. CC/V concluded that the wastewater treatment system either would need to be moved or be improved to provide an acceptable quality of effluent. WHPacific prepared a pre-design report to provide the basis for the final design of a replacement system for the sanitary wastes. The report consisted of a review of the situation and the effluent quality criteria, which led to two alternative plans. We prepared preliminary and final designs of a wastewater treatment system that would produce an effluent acceptable to the client. The design involved a new septic tank, effluent pump station with submersible pumps and force main, and a deeper than usual leach field. WHPacific was responsible for approving construction materials, and providing periodic inspection of the construction.