A longwall face equipment compatibility test is conducted to make sure the system will work as designed for routine longwall mining production operations. The test involves building a mini longwall with the completed yet to be delivered set of equipment, approximately 30 shields long including the head- and tailgate end shields and drives. Just like the pilot shield test, the longwall compatibility test varies but includes both normal and worst case scenerios. As longwall production increases, production delay of any length becomes very expensive and must be avoided as much as possible. All longwall face equipment have various level of automation with various typegs of sensors to monitor various factors for control purpose. The headgate and tailgate must be kept straight, parallel, and at the correct width. The original equipment manufacturers have contracted with coal mines for equipment maintenance work termed as life cycle management of face equipment.