MERSINO's extensive dewatering project had gone into the maintenance stage at Smithland, Kentucky, while the contractor continues work on a $430 million hydroelectric generating facility. Initially, a combination of poor soils and direct proximity to the Ohio River posed a challenge to all. A slurry wall encircles the site, extending from just below ground level to the limestone some 150 ft. below. Just inside the slurry wall, 37 deep wells (drilled to 150 ft.) surround the proposed excavation. As excavation progressed, a circular access road was built approximately fifty ft. below ground level, once again encircling the proposed excavation. 28 wells (drilled to 100 ft. deep) were installed at the lower level, also extending to limestone. This dewatering system was designed to pump as much as 69,000 gallons per minute if needed, in order to keep the excavation dry. Water is discharged through a 12 in. and three each - 24 in. HDPE headers to a sediment pond before being returned to the Ohio River.
As the initial excavation neared completion, some 120 ft. below the adjacent Ohio River, the contractor made plans for approximately 120,000 cubic yards of concrete to be batched for this project. An onsite batch plant was designed to produce the large output with specific mix designs and temperature requirements.
Batching 700 yards of concrete per day would require 20,000 gallons of water per day.In addition, 1500 gallons of water per minute would circulate through aggregate washers and another 650 gallons per minute would be required along wet belts. Making 120,000 yards of concrete requires a lot of water.
MERSINO was contracted to bring the much needed water to the batch plant. Of the 68 dewatering wells, six were discharging through a single 12 in. header that extended to the sediment basin. A tee was cut into this 12 in. header and water was diverted to two 10,000 gallon steel tanks, where multiple pumps and additional piping would direct the water as needed to several different batch plant operations including:
In total, over 4,000 ft. of 1 in. to 12 in. pipe and more than 800 fittings make up the Batch Plant Water Supply System. The system also includes 87 valves & more than two dozen pressure and temperature monitoring gauges. Much of the water system is buried, some within steel casing to protect it from heavy equipment. The 3 in. water supply extends to as high as 54 ft. above ground, where it feeds the concrete batch plant's mixer.
Mersino continues to supply water to this important project. The Smithland hydroelectric facility will add 72 MW of new, renewable generation to the region. Located near Smithland, Ky., the Smithland plant is scheduled to be commercially available in 2015.«Back