DTD drilled and completed one dewatering well at the project site. The well was completed in coal combustion residual (CCR) waste in a lined pond. Most of the material was unconsolidated; however, a compacted zone was encountered, which necessitated the use of a down-hole mud motor for a portion of the drilling.
In addition to the consolidated zone, asbestos waste and a large “magnetic anomaly” were identified during the drilling operations. Two reaming passes were made to enlarge the pilot hole to a diameter of 14”.
The screen and casing materials are composed of 8” diameter, SDR-14, C205 fusible PVC. The well is constructed in a continuous (entry-exit) configuration with 40’ entry riser, 550’ screen (0.040” slot – about 26’ bgs), and 70’ exit riser. Biodegradable drilling fluids were utilized, and well development consisted of jetting a fresh water/enzyme-based breaker solution along with over-pumping. Post well development, a submersible pump was placed in the well, and a sustained flow rate of 25 gpm has been achieved.
