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Whetsto/7e <br />ASSOC/ateS Technical Memorandum <br />the pump column (pump, motor, discharge pipe, and electrical wire) as the pump was <br />lowered into the shaft. It is not clear that 10-ft of clearance exists in the old hoist room at the <br />top of the shaft on the Steve Level. If not, 5-ft joints of 3-inch drop pipe could be special <br />ordered. In that case, 100 segments of pipe would need to be connected as the pump was <br />lowered into the shaft and the total weight would be greater (4,100 pounds) due to additional <br />couplings. Each joint or coupling represents a possible failure point. And although the rock <br />in the Schwartzwalder Mine is competent hard rock, there is no guarantee that the shaft has <br />remained (or will remain) open to that depth. <br />The second method would utilize a boom truck to install the pump through a hole drilled <br />vertically into the shaft from the hillside above the mine. The location of the shaft from the <br />hillside would be difficult to determine, and an underground survey would have to be <br />conducted to tie in to the surface features. If the correct location could be identified, a <br />drilling contractor would have to drill through 300 feet of rock and open cavities without <br />deviation to hit the 74-square foot target of the #2 Shaft (Figure 1). Drilling through open <br />cavities is often more difficult than drilling through competent rock, because there is no hole <br />to stabilize the bit and avoid deviation, and no means of flushing the hole to bring up cuttings <br />from around the bit. Without "return" of drill cuttings, a driller would be drilling blind into <br />the rock below the existing voids, with a high potential for getting the bit stuck in the hole. <br />Few drillers may be willing to take on this challenge, due to the high probability of damaging <br />their equipment. If the hole could be successfully drilled, steel casing would have to be set in <br />the hole to keep the hole open and meet the requirements of the Colorado well construction <br />rules (2 CCR 402-2). Without a "bottom" of the hole, sealing the annular space (as required <br />by law) would be difficult. If well casing were successfully installed, the pump could be set <br />vertically from the surface, provided that the shaft remained open to a depth of 500 feet <br />below the Steve Level. Finally, a buried pipeline would have to be installed on the steep <br />hillside leading down to the water treatment plant. <br />4109C.100731 13