Hawk Measurement Systems of Australia has announced an order for 18 Orca Sonar units for the $2.5 billion Ambatovy nickel mine in Madagascar.Hawk Measurement received an order to provide interface level detectors for all 18 thickeners at the Ambatovy mine. SNC Lavalin in Toronto, Canada, performed the engineering for this phase of the project. They ordered the interface level detectors from Hawk based on successful installations at other mine sites. SNC Lavalin found that the Hawk units were the only equipment available which could meet the temperature specifications, chemical compatibility, EX certification and performance requirements.The Orca systems are based on fourth-generation sonar technology. The transducers selected for this application, will be high-powered, three-crystal array versions, and will require special materials for high-temperature operation and chemical resistance. Each transducer array produces a very high-powered acoustic pulse, allowing the sonar signal to penetrate deeply into the liquid and suspended solids in the tank. The signal is then returned by the change in density at the selected interface level. The Orca control unit processes the raw signal using advanced software. Each unit can monitor two separate interface levels, or one interface level and clarity. Because the outputs from the Orca system are stable, they can be used to control other process functions.