Mount Thorley Warkworth (MTW) is an integrated operation of two adjacent open cast mines in the Hunter Valley region of New South Wales, Australia. It supplies international and domestic markets with semi-soft coking coal and thermal coal.
Rotork plc, Bath, England, has supplied valve actuators for the pipework delivering water to the north and south coal processing (washing) plants from a new 2 Gl dam source. This project has included an actuator for a pipeline supplying water to a new water cart fill point for routine dust suppression operations. Each water cart fill is made up of 120 ton of water, delivered at a pressure high enough to overcome a 10-m rise in the height of the pipework at the point of delivery.
The specification for the actuator to operate the isolation valve on the water cart fill point called for a solar powered, 24 Vdc SIL-rated electric fail-safe actuator, capable of closing a 500-mm butterfly valve in 10 sec. Rotork has been able to satisfy all requirements with a standard Skilmatic Pro electrohydraulic valve actuator.
These self-contained electrically powered actuators are comprised of an integrated control module, hydraulic manifold, and a hydraulic power unit (HPU) consisting of a motor, hydraulic pump and reservoir; and are flexible enough to serve specific applications. The HPU is powered electrically, and an electrical input signal commands the hydraulics to pivot the valve to a control position. An integral spring mechanism moves the valve to a pre-determined safe position in the event of power loss.
The recent incorporation of an intelligent control and monitoring system makes the actuators an ideal solution for two position, safety shutdown or precise modulating control applications.