MUD CIRCULATING SYSTEM - This site uses a waterbased drilling fluid, commonly known as mud or drilling mud, which is a mixture of water, clay, weighting material (barite), and various chemicals. This fluid is critical to maintaining optimal system performance. After mixing & conditioning, the mud is circulated downhole by large slush pumps to satisfy a number of system requirements including, but not limited to, transportation of drill cuttings (solid materials that are broken down in the borehole as a side product of the drilling process) from downhole back to the surface as well as proper circulation of the weighting material during periods when the drill head is immobile. Competitor expansion joints were failing, on average, within an 8 week period after installation.