Lovat Cutterhead, Main Drive System Headed to Virginia

Lovat recently announced that the sale of a new hard rock cutterhead and main drive system to The Kassouf Co. The equipment will be used for the Fairfax (Va.) Water Corbalis to Fox Mill Water Main Project. The project is designed to serve the growing demand for water supply needs by providing facilities to treat, transmit and distribute a safe and adequate potable water supply.

The new components will be manufactured and mated to the existing Lovat RM99 Series 9000 TBM currently owned by Kassouf. This gripper-type TBM will excavate a total length of 8,400 ft, starting at Shaft A and excavating south to Shaft B. The new components consist of a mono-directional hard rock cutterhead, a forward shell and main drive system.

The cutterhead will be equipped with 15.5-in. diameter Lovat single tip disc cutters with replaceable rings. Caterpillar technology will be used in the manufacturing of the steel for the rings.

The forward shell will house the main drive system comprised of a new triple roller main bearing, new motor plate structure and new hydraulic main drive motors, Powered by two 250-hp water cooled electric motors, providing a total of 500 hp to the cutterhead.

Ground conditions anticipated along the tunnel alignment consist primarily of bedrock, mostly diabase with an Unconfied Compressive Strength (UCS) that ranges from 1,750 to 54,700 psi. The Cerchar Abrasivity Index (CAI) of the diabase ranges from 2.2 to 5.5. The expected rock type at the southwestern end of tunnel A is hornfels formation, consisting of altered sandstone, shale and siltstone. The UCS of the hornfels ranges from 13,000 to 21,000 psi. The CAI of the hornfels ranges from 1.3 to 3.1.

The components are scheduled for delivery in early March 2010.