WorldWide Drilling Resource

How Deep Can You Pump? Submitted by Hose Solutions, Inc. I’m sure you can picture a mine shaft with an “ele- vator” that lowers workers and material down where they mine the lateral tunnels at various depths. There is an unnamed copper mine in North America that really likes to dig, and deep. The deepest of these subterranean tunnels is close enough to the bottom that the accumulated drainage water would flood it if left alone. To keep operations moving, the water needs to be pumped. This permanent dewatering has challenges from all directions. First, it’s extremely hot down there. The ambient air temperature is 135ºF (57ºC). The water isn’t exactly like a cool mountain stream either at 185ºF (85ºC). Next, what in the world would we use to hang the massive dewatering pump from? We could use 20-foot sticks of steel, but it would be very cumbersome bringing them all the way down the shaft. And once there, it would be very difficult to connect them together. Additionally, handling steel in these temperatures would be difficult and dangerous, and neither of those options is attractive. And you can forget PVC. Additionally, the drainage water filtering down the shaft and through Mother Earth’s veins becomes very aggressive and corrosive down there. This water would eat through the steel in quick time. So, PVC is out and steel is very challenging. What should we use to hang the pump from? With great success in the past, the pump supplier had recommended flexible drop pipe because it is totally noncorrosive and easy to work with. The pumping level at the bottom of the shaft was 140 vertical feet from the storage tanks which temporarily held the water until it was removed. The flexible drop pipe was ideal because this 8-inch diameter of circular woven polyurethane hose is lightweight and compact. At approximately 2.3 pounds per foot, the 140 feet of hose only weighs about 322 pounds. This “flat packed” roll of hose is only 33 inches in diameter and close to a foot tall. The double-ring clamp stainless steel fittings with male NPT threads were installed. The power cable was attached with straps every 6 feet through a loop in the rib of the hose. The pump was ready to set. A 100-horsepower dewatering pump was suspended from the stout flexible drop pipe. The pump itself weighed 1000 pounds. With a 46,000-pound tensile strength, the pump along with the weight of the power cable, straps, and water were not even close to pushing the limits of the polyurethane hose. The project was a smashing success! Oh, by the way, in answer to the question in the title of this article, the pump was hanging at approximately the 6893-foot level in the shaft. Pretty crazy. " # # # " "# # ! #! % # !! " ! " "# ! & ! % ! # ' ! & !! #' " $!"# " # " ##" " " " " $# " !!! 27 WorldWide Drilling Resource ® DECEMBER 2015 Merry Christmas & Happy New Year! The WWDR office will close at noon December 23 rd , and reopen December 28 th -31 st with minimal staffing. We will be closed January 1 st . We wish you and yours a joyous holiday season!