At one time, glaciers up to a mile thick covered two-thirds of the state of Ohio. When the last ice age in North America ended around 10,000 years ago, the receding glaciers left behind large deposits of highly permeable sand and gravel, known as glacial outwash. Today, the Great Miami River transports a large amount of this outwash and deposits it where flow conditions change, including in the slower currents running through the city of Hamilton.
The local water authority contracts with Welch Sand & Gravel to remove outwash from a 15-acre section of the river in Hamilton. Welch is only allowed to excavate to a depth of 3-4 feet, to prevent the outwash from moving further downstream and to keep the summer pool area open. The popular pool is used by the local community for recreational activities including fishing, boating, canoeing, and other water sports.
Welch operates the Metso Lokotrack ST3.8 mobile screen at the Black Street Bridge site in Hamilton, where the company has a seasonal permit allowing them to mine river gravel from March through December. They have had the permit for this work since 2004, and the amount of material removed each year varies depending on the weather. “We have done as much as 119,000 tons, with an average of 50-78,000 tons out of the Great Miami River operation,” says Rick Goessling. “It all depends on the amount of rainfall and flooding that takes place.”
Efficiency with new screen
The new ST3.8 mobile screen replaces an older model Metso ST356 screen in operation since 2006. “We ran that ST356 mobile plant for about 10-11 years, and we wore it out,” says Production Manager Rick Goessling, who has been with the company since 1981. “We ran millions of tons of gravel through that thing,” he added, “and we just decided it was time to update, so we called Process Machinery.” Process Machinery, Inc. (PMI) is Metso’s distributor in the states of Ohio, Kentucky, and Indiana. After conferring with PMI Senior Sales Manager Gary Honchell, Welch Sand & Gravel decided to purchase the new Lokotrack ST3.8 screen.
“Our customers want equipment that will last,” says Honchell. “Metso’s new mobile screens are not only built sturdier, but most of the key parts are galvanized for longer life at no additional cost.”