A first person account of mine longwall dewatering solutions
When mining companies in Alabama have problems, they look to Jim House & Associates (JH&A) for solutions.
Such was the case when a large mining company needed to keep water off of the longwall face underground and they looked toward Jim House & Associates to provide them with a solution.
JH&A has been in business since 1957 and is a premier solution provider in the Waste Water and the Mining/Industrial business. They have offices and full service shops in Birmingham and the Gulf Coast region in Alabama.
Mark Hall, a team member with JH&A, is a 25 year underground coal mining veteran and mining dewatering expert. He has been with JH&A for the last five years providing consulting, service and solutions for the mining and industrial sectors.
When Mark first called Cornell Pump with the application, it sounded easy enough. As he began to describe the application, confidence began to fade. He said “can’t is not an option” so Cornell had to figure something out.
The project required the ability to pump water from a sump that was located 1800’ from the longwall tailgate. This meant an 1850’ suction line with a very shallow low spot or sump as the water source. The elevation of the sump was 675’ and the elevation of the pump was 670’. The problem was not only the length of the suction line, but also the fact that line had multiple dips and rises along its length which kept the water from free flowing due to entrapped air.
Cornell, working with the JH&A team, found a viable solution. We proposed a 6NNT-F16 Redi-Prime® pump to remove the water and keep it off the long wall face once the longwall mined past the location. Based on the flow conditions, an appropriate line size for the suction was recommended that would minimize friction loss thus allowing Cornell to select a pump with the sufficient NPSHR to do the job. Cornell’s engineers calculated that a 12” suction line along with the 6NNT Redi-Prime®.
Another one of Mark’s favorite sayings is “Plan your work, and then work your plan. ” According to Mark, it was imperative that we keep as much water off the longwall face as possible. As they mine past these sumps, the electric MSHA submersibles pumps have to be pulled when the face reaches them. Mark explained that if Cornell Pump could provide an end suction pump to handle the water out of the tail gate entry then we could add a value for our customers that would be unprecedented. After we received all of the parameters we started to “work our plan.”
Cornell’s Redi-Prime® pumps are designed and engineered for the most rugged and demanding industries. Cornell’s Redi-Prime® system is also designed with the environment in mind. Cornell’s Redi-Prime® system utilizes a positive sealing float box and a mechanically driven low maintenance, high volume vacuum pump for rapid priming. This design allows absolutely no water carry-over from the priming system into the environment. Cornell Redi-Prime® pumps are also equipped with Cornell’s patented Cycloseal® and our Run Dry™ feature which extend seal life and protect the mechanical seal from damage caused by running dry.
Another issue faced was a very shallow sump, only 3’ deep. Engineering was concerned that once the suction started the application would experience vortex and introduce air into the system. Mark said “I can fix that.” He made a 5’ long strainer made out of 12”PVC pipe and drilled quarter inch holes in the bottom half of the pipe. Then he put a cap on the end of it and there was zero vortexing once the pump started. Mark, along with the mining company planned and ran the suction line down the #2 entry before there were any issues with falls of roof. Once we had everything in place and started the system we walked the suction line to listen for air leaks. We found multiple locations where the PVC suction pipe was introducing air into the system. Mark pulled out another trick and used clear shrink wrap to wrap around the couplings to stop the leaks. Once Mark controlled the leaks the Cornell 6NNT End Suction pump took 50 minutes to evacuate all the air from the 1850’ 12” suction line allowing the water to be transferred to another sump. This application kept water off the long wall face as they passed by the water. The long wall is 1600’ past the installation point and the Cornell is still pumping and the long wall face is dry with absolutely no loss of production due to water issues on the face!
JH&A’s willingness to trust Cornell with this tough application allowed us to take another step forward in our endeavors to increase our presence in underground mining applications, not only in Alabama, but across the world.